Spinal News International 53 - November 2019

November 2019 | Issue 53 Jeffrey Wang: The future direction for NASS

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Margareta Nordin:

Profile

Jay Jagannathan: IONM for complex spinal surgery

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Short-segment TLIF can increase lordosis in fused segments

Image courtesy of ©️EUROSPINE/APACE PLC 2019

Short-segment transforaminal lumbar interbody fusion (TLIF) can increase lordosis within fused segments, and reduce compensatory mechanisms in the unfused lumbar spine. This was the conclusion presented by Markus Loibl (Schulthess Klinik, Zurich, Switzerland) at the EUROSPINE annual meeting (16–18 October, Helsinki, Finland). Loibl and colleagues received the prize for Best-of-Show Paper at the meeting.

Markus Loibl

T

he retrospective study aimed to evaluate the magnitude of change in segmental and regional lordosis in short segment TLIF (1–3 segments) and its effect on spino-pelvic alignment. The study team also sought to determine whether an increase in segmental lordosis can be associated with a better clinical outcome for patients. Loibl and colleagues had initially hypothesised that patients with a better aligned lumbar spine after short-segment TLIF would have a

more favourable clinical outcome at the two- and fiveyear follow-up stages.

Through the local spine registry at Schulthess Klinik, the study team identified 196 patients with no coronal deformity >20 degrees and no previous spine surgery who had undergone TLIF (1–3 segments) for degenerative spinal disorders in 2012, who formed the basis of the study. The cohort comprised 106 patients Continued on page 2

Elective one to three level ACDFs at physician-owned hospitals cost less and have fewer complications The results of a recent study suggest that elective one to three level anterior cervical discectomy with fusion surgeries (ACDFs) at physician-owned hospitals have significant cost savings and lower odds of experiencing 90-day medical complications and readmissions. These findings were presented by first author Azeem Tariq Malik during a Best Paper session at the 34th Annual Meeting of the North American Spine Society (NASS 2019; 25–28 September, Chicago, USA).

THE STUDY TEAM, led by Azeem Tariq Malik and Safdar N Khan, noted that due to concerns regarding higher cost and low quality of case provided in physician-owned hospitals, the Affordable Care Act (ACA) imposed sanctions that prevented the formation of new physician-owned hospitals and limited expansion of current facilities in the USA. They argued that, with the demand for spine care growing, there is a need for re-evaluation and assessment of quality of spine surgical care provided at these physician-owned hospitals.

Malik and colleagues utilised the 2005–2014 Medicare 100% Standard Analytical Files (SAF100) to identify patients undergoing elective one to three level ACDFs at physician-owned and non-physicianowned hospitals. The investigators reported that 6,692 (2.7%) patients received an elective ACDF at a physician-owned hospital (n=45; 2.4%) whereas 249,499 (97.3%) received surgery at non-physicianowned hospitals (n=1,843; 97.6%). The majority Continued on page 2

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November 2019 | Issue 53

Conference coverage

Short-segment TLIF can increase lordosis in fused segments

Elective one to three level ACDFs at physicianowned hospitals cost less and have fewer complications

Continued from page 1

If we increase segmental lordosis by three degrees we find a corresponding significant reduction of lordosis in the remaining segments.”

Editors-in-chief:

Professor Gunnar Andersson (USA) Dr Alexis Kelekis (Greece) Professor Christopher Bono (USA)

Publisher:

Continued from page 1

Image courtesy of ©️EUROSPINE/APACE PLC 2019

who had degenerative spondylolisthesis, 32 with isthmic spondylolisthesis, and 58 with osteochondrosis. The majority of the patients underwent mono-segmental fusion (140) or bi-segmental fusion (50), and six underwent three-segment fusion.

The study team assessed radiological parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL), L4–S1 lordosis, fused segments lordosis (FSL), and remaining unfused segments lordosis (RSL) on standing lumbar spine radiographs taken before and six weeks after surgery.

Based on these measurements, Loibl and colleagues assessed the patients’ spino-pelvic alignment (PI-LL) and lumbar-Global Alignment and Proportion score (L-GAP), and they were then categorised as either balanced, unbalanced, or uncompensated according to PI-LL, and proportioned, moderately disproportioned or severely disproportioned according to L-GAP. The Core Outcome Measures Index (COMI) was used to assess the patient-rated outcome at the pre-operative stage, and at both two and five years post-operatively.

The results presented by Loibl showed that there was no significant difference in the radiological measurements pre-to-post-operatively, except for FSL, which was increased from 21.9±10.4 degrees preoperatively to 23.4±9.2 degrees post-operatively (1.3±4.5 degrees per fused segment) (p<0.01). Loibl and colleagues also found that the proportion of patients in the PI-LL and L-GAP score categories showed no significant differences before to after surgery.

“This was actually quite surprising,” Loibl remarked in his presentation of the findings at the EUROSPINE annual meeting. He went on to explain that the results showed that there was a low but significant correlation between the increase in FSL and the decrease in RSL

Bottom L-R Tamás Fekete, Tim Pigott and Thomas Blattert chaired the EUROSPINE Best-Of-Show session at Messukeskus (top) in Helsinki

(R=-0.285, p<0.01) noted in patients. The COMI improved significantly from 7.2±1.7 at baseline to 2.5±2.5 and 2.8±2.5 at two and five years postoperatively. Patients were more likely to achieve the minimal clinically important change (MCIC) in COMI score at five years postoperatively if the FSL was increased by >three degrees (87.9%) than if it was increased by <three degrees (72.6%) (p=0.03), the study’s authors found.

Turning to compensatory measures, Loibl noted: “If we increase segmental lordosis by three degrees we find a corresponding significant reduction of lordosis in the remaining segments. We also find a significant reduction of the pelvic tilt. It is very small, but it shows the very sensitive system of the spine and the pelvis, and that we can influence this system with these short segment operations.”

Loibl and colleagues concluded that short segment TLIF can increase lordosis within fused segments, and reduce compensatory mechanisms in the unfused lumbar spine. A good clinical outcome is achieved, they noted, for the majority of patients at the five-year follow-up stage independent of spino-pelvic alignment. However, an increase of lordosis in the fused segments of more than three degrees appears to be associated with a better clinical outcome.

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The findings promote the re-introduction of physician-owned facilities in the current value-based healthcare system.” p=0.015), renal complications (OR 0.74 [95% CI 0.64–0.86]; p<0.001) and readmissions (OR 0.83 [95% CI 0.71–0.97]; p=0.019).

They found no significant differences between physician-owned vs. non-physician-owned hospitals with regards to wound complications (p=0.187), pulmonary complications (p=0.241), urinary tract infections (p=0.077), pain complications (p=0.984), dysphagia (p=0.905), and revision surgery (p=0.209).

Although the authors caution readers about possible unseen selection bias, the results of the study show that patients undergoing surgery at physician-owned hospitals do not have a worse outcome. The findings promote the re-introduction of physician-owned facilities in the value-based healthcare system.

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of patients in both the physician-owned hospital cohort and the non-physician-owned hospital group were more than 65 years of age (40.3% and 39.1%, respectively).

After controlling for age, gender, region, hospital factors (including socioeconomic status, urban versus rural location and volume) and Elixhauser Comorbidity Index, they found that undergoing ACDFs at physician-owned hospitals was associated with lower odds of cardiac complications (OR 0.8 [95% CI 0.73–0.86]; p<0.001), septic complications (OR 0.87 [95% CI 0.71–0.96]; p=0.007), deep venous thrombosis (OR 0.71 [95% CI 0.54–0.93];

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November 2019 | Issue 53

Conference coverage

Taking NASS to the global stage Outgoing North American Spine Society (NASS) president Jeffrey Wang (Keck School of Medicine, Los Angeles, USA) talks to Spinal News International about the organisation’s increasing international focus, highlights from the society’s 34th annual meeting (NASS 2019; 25–28 September, Chicago, USA) and the future of robotics in spinal surgery.

As outgoing president of NASS, what have been the main highlights of the year for you?

It has been a great year, very busy. I always encourage people to take a look at all the different things that NASS does, we do so much more than just the annual meeting. And, as president I have got a great appreciation of that. I realise that the meeting has given us credibility as a society within the North American aspect, but internationally it gives us a tremendous amount of credibility, and so we have seen a huge amount of international interest both in our membership and attendees of the meeting.

During my year as president, one of my two main focuses was international. At our recent board meeting, we approved a huge infrastructure of NASS international committees and commissions, and a position on the board for that, so that we now have a dedicated area of NASS that is focused on international issues. Patrick Hsieh is the chair of the international committee, and we also have Michael Picariello who is full time with NASS. We are very serious about our international focus and we have got organised on our

side because we are getting overwhelming talk-type setup in one of the rooms, plus requests, not only to attend meetings, augmented reality, we are doing a tumour but to collaborate in international session. The format has changed but we courses and meetings, and to help set also have all of the great research we up research guidelines and journals. usually present.

There is also demand to set up NASS chapters throughout the world, to help In this increasingly digital with advocacy in other countries. Next age, why is it still important year we are doing our first international that attendees come to these meeting—Summer Spine—in Bangkok. meetings?

There is a huge amount of international Nowadays, we have access to so many Jeffrey Wang collaboration, but at a deep level, not news stories, but it is filtered and there just doing a course at a meeting. We is an influence from the venue that is are bringing all of the societies together, and we are releasing it. If you wait for peer-reviewed publication developing deep relationships internationally. that takes years, and if you are relying on that for information you are years behind. It is better to hear What have been your highlights from it directly from the experts, and to understand the the annual meeting this year? philosophy. Reading about robotics in isolation is I changed the meeting this year to make it completely different than when you go and you see the experts different to how it has been in the past. Previously, demonstrating it. You can understand and get a feel programming was created to reflect the ideal makeup for the philosophy, and that is important for any of the attendees, with just as many surgeons as nonspine practitioner. surgeons, but now the programme makes sense. If you analyse the programme we have better content for What are going to be the biggest the non-operative specialists. In the past there was a developments in spine in the next five to

We are developing deep relationships internationally.” huge amount of tailored content, but it was haphazard throughout the meeting. Now throughout the whole meeting you have enough programming to satisfy.

And, the surgical side has just exploded. Right now, we have surgical demonstrations, with expert surgeons performing the surgery, demonstrating it in a way that allows attendees to ask questions. We have a new TED

Topical steroid reduces dysphagia after ACDF, early RCT results suggest Early postoperative results of a double blind randomised clinical trial demonstrated the benefit of local intraoperative corticosteroids (LIC) delivered with an absorbable haemostatic matrix to prophylactically reduce dysphagia following anterior cervical discectomy and fusion (ACDF) surgery. The findings were superior for the treatment group, especially two-days postoperatively, and were maintained at one month.

A

lthough dysphagia is a common complication in the setting of ACDF surgery, Daniel Stein (Hospital for Special Surgery, New York, USA) note that there is controversy in the literature regarding the effectiveness of LIC in reducing postoperative dysphagia.

The authors therefore conducted the study to determine if the application of an LIC during multilevel ACDF surgery impacts early postoperative dysphagia severity.

Senior investigator Todd J Albert recently presented these early results during a Best Paper session at the 34th Annual Meeting of the North American Spine Society (NASS 2019; 25–28 September, Chicago, USA), concluding that treatment arm had “significantly better” dysphagia scores than the control arm.

A total of 106 adult patients

undergoing primary multilevel ACDF (defined as between two and four levels) at a single institution were enrolled in the study. The patients were randomised in a double blind fashion to either arm S (Steroid) or the control arm (C). Arm S received 1ml (40g) of methylprednisolone acetate delivered with an absorbable haemostatic matrix (vehicle) to the retro-oesophageal space prior to closure. The control arm only received the vehicle prior to closure.

The study group collected dysphagia specific instruments (EAT-10 and the SWAL-QOL) preoperatively, and at day one, day two, and one month postoperatively. Potential randomisation biases were assessed by comparing the preoperative characteristics and surgical treatment of the two arms.

Stein and colleagues comment: “Both arms demonstrated similar preoperative

10 years?

I think robotics and navigation. Navigation has been around for a long time, and when it was first introduced lot of us questioned the cost and whether it was worth it.

Now, it is really integrated into the mainstream practice and, looking back, we are asking why we did not jump on the bandwagon right away. I wonder if robotics is like that. Robotics is sexy right now, and it is a great marketing tool, but what if you fast forward five years and we are looking back to 2019 and saying that this is the bandwagon we should have jumped on then, just like we did with navigation? We need to take the next step.

People know that there is a next step out there and that is why they are so excited.

characteristics and underwent similar surgical procedures.” A Friedman test was used to investigate change over time in patient reported outcomes (PRO); a Mann-Whitney U test was performed to compare the median PRO scores (S versus C) at each time point.

Ninety-five of the patients included in the study—representing 90% of the cohort—had complete datasets and were included in the analysis. Mean age of the patients was 57.6 years, and just under half were female (48.4%). The most common diagnoses were cervical spondylosis (63.2%), radiculopathy

This study […] opens the door for further study on the effect of fusion and longer term swallowing function and health outcomes.”

(48.4%), myeloradiculopathy (30.5%), and myelopathy (24.2%).

Preoperatively, the investigators found no significant difference in PRO scores, with the exception of the EatDesire domain (p=0.049), but medians

were similar. Overall, and for each randomised arm, significant change in dysphagia scores were observed from pre- to postoperatively. Furthermore, the comparison of postoperative PRO across the study arms revealed that the S arm had better SWAL-QOL scores in Food Selection (p=0.049, 87.5 [50–100] vs.

75 [37.5–100]) and Fear (p=0.027, 100 [89–100] vs. 93.7 [75–100]).

At postoperative day two, the S arm had better dysphagia scores in Burden (p=0.02), Eat Duration (p=0.008), Fear (0.017), Fatigue (p=0.047), and modified Eat-10 (p=0.013) categories. Finally, better dysphagia scores were maintained one month postoperatively in terms of Eat Desire (p=0.015), Eat Duration (p=0.046), Fear Swallow (p=0.016), and Fatigue (p=0.003).

The comparison of the control arm (n=47) and the S arm (n=48) revealed no significant difference in the demographics, diagnosis, or surgical information in numbers of levels fused (2.57±0.6 vs. 2.47±0.68, p=0.268), operation time (150min±37 vs.

136min±33, p=0.065), or estimated blood loss (100cc±42 vs. 90cc±52, p=0.358).

Talking to Spinal News International, Albert commented: “This study demonstrates the efficacy of local steroid application in decreasing short-term swallowing difficulty after multilevel ACDFs, and opens the door for further study on the effect of fusion and longer term swallowing function and health outcomes.”

Issue 53 | November 2019

Conference coverage

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Decompressive surgery remains the gold standard for lumbar stenosis compared to interspinous process devices Long-term results demonstrate that, even though implantation of a stand-alone interspinous process device (IPD) can be successful in treating intermittent neurogenic claudication (INC), the high reoperation rate does not justify its use and simple decompression is more effective. This is the finding of a five-year double-blind RCT, results from which were presented at the 2019 EUROSPINE annual meeting (16–18 October, Helsinki, Finland).

SHORT-TERM RESULTS comparing IPD to conventional decompression in patients with INC due to lumbar spinal stenosis provide evidence that clinical outcomes are comparable, but that reoperation rates are higher, Catharina Schenck (University Medical Centre, Leiden, The Netherlands), the study’s lead author told the EUROSPINE audience. Schenck and colleagues focused on long-term, five-year results of this comparison.

Patients with neurogenic claudication due to lumbar spinal stenosis at one or two levels who had failed to respond to conservative treatment between 2008–2011, were randomised to receive either standard bony decompression or standalone implantation of an IPD (Coflex). A total of 159 patients were randomised at the five participating neurosurgical centres, 80 participants received an interspinous process device without bony decompression and 79

participants underwent only spinal bony decompression. Patients and research nurses remained blinded for up to one year after surgery.

The primary outcome at five years was the score for the Zurich Claudication Questionnaire (ZCQ), and secondary outcome measures included Visual Analogue Scores (VAS) for back pain and leg pain. Repeated-measurement analyses were applied to compare outcomes over time.

Schenck said that the recovery rates based on the ZCQ were similar for the two groups, with 68% in the IPD group having experienced successful recovery, compared to 56% in the standard decompression group. Reoperations, because of absence of recovery, remained significantly higher in the IPD group compared to standard decompression with comparable reoperation rates at two and five years, Schenck and colleagues found. Long-term back pain was lower

in the IPD group compared to the bony decompression group. This contrasts with two-year results where the VAS back pain was higher in the IPD group compared to standard bony decompression.

Schenck said: “I think we can conclude that the reoperation rates in the IPD group are higher at two years, and in ongoing analysis we see comparable results at five years, and self-reported back pain seems lower for the IPD group at five years. The reoperation rate in the IPD group is high and the cost for the IPD adds to the disadvantages,

but in spite of this I think we can say that once the IPD works, it works.”

Standard decompression remains the golden standard, Schenck said, since it is effective and lacks the disadvantages of the IPD. The study’s authors note that the difference in VAS back pain between both treatment groups at five years might be statistically significant, but is clinically probably non-relevant.

Implanting an IPD is not unacceptable, but it is a costlier alternative for decompressive surgery carrying a higher reoperation risk, they note.

The reoperation rate in the IPD group is high and the cost adds to the disadvantages, but in spite of this I think we can say that once the IPD works, it works.”

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November 2019 | Issue 53

Advertorial

THIS ADVERTORIAL IS SPONSORED BY B.BRAUN

SpineScan—A key to lean process management of spinal instruments and implants for improved quality, efficiency and significant cost reduction Less is more—The increasing economic burden and complexity in hospital processes forces hospitals to improve their structures and processes to increase treatment quality and patient safety. The implementation of lean projects for an overall increase of efficiency as well as quality improvements seem to be promising key factors. This is where SpineScan, an additional service concept within the Ennovate® platform, comes in. The lean tray management for general and specific instruments such as the Ennovate® platform have an economic impact on all primary and secondary processes in and around the operating theatre. Ennovate® is the platform, based on ONE screw and ONE system for all pathologies with a lean modular instrument set and sterile packed implant line to streamline the sterile goods related processes and increase patient safety.

SpineScan—Ennovate® solutions beyond fusion

Hospitals are facing economic challenges. The operating theatre is of particularly high importance economically as 60–70 % of the turnover of a hospital is achieved there.2 Considering that each operating minute creates costs of about €15,3 each delay or extension of an operation should be avoided.

Furthermore, hygienic aspects, dissatisfaction of employees and the condition of the surgical goods4,5 have additional impact on the processes and costs in the operating theatre.

If we take a closer look at the cost drivers, it can be said that the increasing number and complexity of instrument systems used in the hospital lead to economic challenges.

Less is more— Ennovate® convinces with its lean tray configuration

But how may hospitals detect hidden costs and optimisation potentials in their daily workload, complexity of processes and systems?

This is where the SpineScan for thoracolumbar pedicle screw systems together with the Ennovate® platform comes in. B.Braun has been offering a wide range of service solutions for a number of years to meet the individual needs of a hospital.

The SpineScan for pedicle screw systems provides a trend-setting economical decision base for clinical management, sterile processing departments and material managers. It creates transparency on the usage rates of materials, assets, as well as production insights and example cost Ennovate® supply carts calculations. It reveals for customized implant potentials to increase configuration

and optimise process efficiency in using the Ennovate® platform. The analysis may be extended on basic instrumentation, intra-operative processes, logistics, instrument quality, and the post-operative instrument management.

The key—Sterile goods data analysis

The key of the SpineScan is the analysis of sterile goods data from the instrument management system of sterile processing departments.

Ease of use–For hospitals without digital and professional material management systems, B.Braun offers the tray organizing manager TOM for prospective data analysis. TOM is THE all new digital Tray Organizing Manager – an easy to install app-based platform solution designed to optimize the processes of any sterile processing department which is very easy to handle. It is definitely what your staff in sterile departments will embrace.

The sterile goods data analysis for general instruments gives transparency about the variety of instrument types, different suppliers, production data as well as potentials of reorganisation and standardisation to enhance efficiency and economy of material management.

The sterile goods data analysis for the thoracolumbar pedicle screw systems is an in-depth analysis of the assets, set turns, usage rates, tray structure, reprocessing insights, and cost calculations. It also puts the set turns and related efficiency rates of each set in relation to the performance per intervention.

It shows that one of the major cost drivers in the washing-, cleaning- and sterilization process are nonsterile packed implants. Which always means: using six screws on average but processing often more than 200 screws in the same rack.

Ennovate® captivates with its simplicity. We were able to reduce the number of trays by 50% while improving the efficiency of our whole patient care value-added process.

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A change to sterile packed screws can be a game changer: 100 % safe tracking always ready to use implants no cross-contamination no risks with material questions after 100 or more process cycles Extension modules of the SpineScan may also be: Intra-operative scan Logistic scan Instrument quality scan Post-operative instrument management scan These modules show transparency in the usage rates of instrumentation in the operating theatre as well as possible savings in the time periods between the interventions. Logistic aspects such as current set-up of sterile stocks or case caddies are evaluated.

Concerning the instrument quality scan, findings may be related to the quality of general instruments in a spot scan on site. It categorizes the inventory according to instruments with findings in surface, function or replacements. Also the post-operative instrument management scan analyses possible optimisation potential concerning cleaning, disinfection and sterilisation including packing and training of personnel.

Ennovate® solutions beyond fusion – SpineScan as an additional service concept gives transparency about the status of the hospital and shows optimisation potentials for a trend-setting economical decision base.

The change to a spinal platform like Ennovate® may have considerable optimisation potential concerning costs, processes, employees’ satisfaction and treatment quality.

References 1. Kaplan S, Sadler B, Little K, et al. Can sustainable hospitals help bend the health care cost curve? Issue Brief Commonwealth Fund pub. 1641. 2012 Nov; 29: 1–14 2. Travis Healey et al. Improving Operating Room Efficiency, Part 1; 2015 3. Wilfried von Eiff. Ganzheitliche Prozessoptimierung bei Knie-TEPProzeduren; 2015 4. OP Barometer, 2017 5. Hygieneradar, 2018

Issue 53 | November 2019

Neck disability

Prioritisation of realignment associated with superior clinical outcomes for surgical cervical deformity patients According to new research, certain ratios of correction of cervical parameters contribute to improving neck disability. The study, authored by Katherine E Pierce (NYU Langone Medical Centre, New York, USA) and colleagues, was recently nominated for Best Paper at the 34th Annual Meeting of the North American Spine Society (NASS 2019; 25–28 September, Chicago, USA), where Pierce presented the group’s findings.

SPECIFICALLY, THE AUTHORS— Pierce and colleagues—note that certain cut-offs of radiographic differences from baseline to one-year were found prioritising C2–T3 angle, followed by cervical lordosis, C2 slope, C2–C7 plumb line, and McGregor’s slope, all strongly associated with meeting the minimal, clinically important difference for the neck disability index (NDI) score. They conclude: “Prioritising these radiographic alignment parameters will optimise patient-reported outcomes for patients undergoing cervical deformity surgery.”

The investigators note that many patients are unable to undergo a major cervical deformity corrective surgery due to deformity severity, age, comorbidities, and overall frailty status. Therefore, “in order to optimise quality of life in patients with cervical deformity, there may be alignment targets to prioritise,”

the authors suggest. The purpose of the present study, a retrospective review of a multi-centre prospective cervical deformity database, was to prioritise the cervical parameter targets for alignments.

A total of 77 patients undergoing cervical deformity corrective surgery were included in the study. Outcome measures included cervical regional alignment parameters—namely the cervical sagittal vertical axis (cSVA), cervical lordosis (CL), T1 Slope minus CL (TS–CL), chin brow vertical angle (CBVA), McGregor’s slope (MGS), C2–T3 plumb line (C2–T3 SVA), C2–T3 angle, and C2 slope—as well as healthrelated quality of life measures such as the neck disability index.

A backwards linear regression model, including radiographic differences as predictors from baseline to one-year for meeting the minimal clinically

important difference (MCID) for NDI, demonstrated an R2 of 0.820 (p=0.032).

By primary Ames driver, 67.5% of patients were categorised as C, and 32.5% as CT. Ratios of change in predictors for MCID NDI patients for C driver patients were 260.8% MGS, 140.3% CL, 121.2% C2–T3 angle, 49.6% C2 slope, 41.1% cSVA, 20.5% TS–CL, 3.1% cSVA, 27.5% C2 slope, 24.9% TS–CL, and 13.7% C2–T3 SVA. Summing up the findings, the authors comment: “The ratios were not significant between the two groups [p>0.05].” They note that decision tree analysis determined cut-offs for radiographic change, prioritising in the following order (based upon original regression values): a correction ≤42.5 degrees C2–T3 angle (OR: 5.667 [1.074– 29.891], p=0.041), <35.4 degrees CL (OR: 4.636 [0.857–25.071], p=0.075), >-31.76 degrees C2 slope (OR: 3.2 [0.852–12.026], p=0.085), >-11.57mm cSVA (OR: 3.185 [1.137–8.917], p=0.027), >-2.16 degrees MGS (OR: 2.724 [0.971–7.636], p=0.057).

The investigators included cervical deformity patients with full baseline and one-year radiographic parameters and NDI scores, as well as patients with cervical or cervicothoracic Primary Driver Ames type. Patients with baseline Ames classified as low cervical deformity for both parameters of cSVA and TS–CL were excluded from the results.

The patients included in the study had an average age of 62.1 years and 64% of

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the cohort were female. Average charlson comorbidity index (CCI) was 0.94 and 7% were current smokers. By approach, the majority of cases were posterior (41.6%), followed by a combined approach (39%), and finally anterior (19.4%). The mean number of anterior levels fused was 3.5, while the figure for posterior was 8.3. Average operation time was noted as 553.1 minutes and mean estimated blood loss (EBL) was 1128.1 cubic centimetres (ccs).

The authors comment: “The goal was to establish an order of targeting alignment parameters and [the patients’] projected minimal corrective degree to benefit operative decision-making and inherently improve Health Related Quality of Life (HRQL) management.”

In conclusion, the authors note: “The analysis determined that prioritising regional cervical radiographic alignment parameters in a certain order to a specific degree optimised reaching the minimal clinically important difference in a patient’s self-reported neck disability.

Addressing the intertwined cervical parameters in a specific order to a certain degree of correction can contribute to improved patient-reported neck disability.”

Looking forward, Pierce and colleagues suggest that future studies should investigate the proposed prioritisation and thresholds on a prospective trial with a larger, homogenous population of patients undergoing cervical deformity corrective surgery.

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November 2019 | Issue 53

Artificial intelligence

AI-based classification may guide preoperative decisions in ASD patients

clusters based on the patient characteristics: young coronal patients, with a mean age of 36 years and an average mean coronal deformity of 52 degrees; old primary patients, with a 58-year mean age, a mean average of 39 degrees coronal deformity and with no Hierarchical clustering of patient data using artificial intelligence (AI) can identify patterns revisions; and old revision patients, with a mean age of that may guide preoperative decision-making in adult spinal deformity (ASD) surgery by 62 years, with larger sagittal deformity and less coronal predicting outcomes and major complications, a collaborative study by the International deformity. Around 80% of patients in the old revision Spine Study Group and the European Spine Study Group has indicated. Ferran Pellisé (Vall cluster had previously undergone surgery. d’Hebron Institute of Research, Barcelona, Spain) presented the findings most recently These clusters and surgery types were filtered and at the EUROSPINE annual meeting (16–18 October, Helsinki, Finland), where the paper back-walked to provide decision trees intended to help featured in the Best-of-Show session. The paper was originally presented at the Scoliosis the user identify which cluster that patient and the Research Society annual meeting (18–21 September, Montreal, Canada) by lead author surgery belonged to. Normalised two-year improvement Christopher Ames (UCSF, San Francisco, USA). Miquel Serra-Burriel (UPF, Barcelona, and major complications were computed both for the Spain) was the lead AI data scientist for this work. patient and surgery clusters and were used to create an efficiency grid. Pellisé noted that this n the study, Ames and Pellisé note that AI-based, was to have this information at the helps to identify the treatment patterns unsupervised clustering provides a wide view of point of care without the need for yielding the optimal calculated quality outcomes and complications, and can be used when computer access. of live improvement, with the lower risk outcome calculators are not feasible or available.

To build their classification model, risk major complications. At SRS Ames Cluster-based risk/outcome classification will likely the authors analysed data from a cohort commented: “This same analysis shows us have a significant impact as a decision support tool, of 1,245 ASD patients taken from the that contrary to what most people might Pellisé said at EUROSPINE. Ames noted at SRS ISSG and ESSG databases with baseline, believe, patients with greater complication 2019 that the surgeon of the future will be a ‘chimera’ one-year and two-year health-related risk at the same time have greater benefits, combining human and artificial intelligence to improve quality of life and surgical data queried. so this is something that we have to patient care.

For unsupervised cluster analysis, the take into account. In counterpart, young Through the collaborative analytics study, the US authors fitted dendograms, one with coronal patients with less risk, they also International Spine Study Group (ISSG) and the surgical features, and another with patient Christopher Ames have less functional gain.” This may European Spine Study Group (ESSG) aimed to create a characteristics. Both were built using have significant implications for how risk-benefit adult spinal deformity (ASD) classification Ward distances and optimised with the gap method. government-based healthcare systems with limited or efficiency grid using AI unsupervised cluster analysis Patient characteristics observed included age, sex, height resources spend their healthcare budgets in the future, which is intended to assist surgeons and patients to and weight, and number of previous surgeries. according to Ames. identify treatment options yielding the highest healthBased on the surgical characteristics, the cluster As well as helping to aid decision-making related quality of life improvement, combined with analysis defined five surgical clusters: short fusion preoperatively through predicting outcomes and the lowest risk. In his presentation, Pellisé noted that with single posterior column osteotomy; long posterior major complications, the joint ISSG and ESSG study there are existing, reliable individual models to predict spinal fusions; multiple posterior column osteotomies; concluded that ASD classification pattern identification outcomes, complications, and reintervention following interbody fusion without decompression; interbody could help to facilitate treatment optimisation by spinal deformity surgery, but that there is a need for fusion with decompression, and patients with threeeducating surgeons on which treatment patterns yield computer access to be able to get a prediction. The goal column osteotomies. The analysis identified three optimal improvement with the lowest risk.

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Computer-aided method has potential for measuring Cobb angle on chest X-rays A new study, recently published in the European Spine Journal, suggests that a computer-aided method has the potential for automatic Cobb angle measurement and scoliosis diagnosis on chest X-rays. As the Cobb angle is involved in therapeutic decisions of scoliosis, the authors emphasise the “crucial” nature of the reliability and accuracy of this measurement.

THE INVESTIGATORS, YALING Pan (Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China), Qiaoran Chen (Shenzhen YiYuan Intelligence, Shenzhen, China), and colleagues, used two Mask R-CNN models as the core of a computer-aided method to separately detect and segment the spine and all vertebral bodies on chest X-rays, and the Cobb angle of the spinal curve was measured from the output of the MASK R-CNN model.

To evaluate the reliability and accuracy of the computer-aided method, Pan, Chen, and colleagues measured the Cobb angles on 248 chest X-rays from lung cancer screening using a computeraided method, and two experienced radiologists used a manual method to then separately measure Cobb angles on

the aforementioned chest X-rays.

For manual measurement of the Cobb angle on chest X-rays, the study’s authors note, the intraclass correlation coefficients (ICC) of intra- and interobserver reliability analysis was 0.941 and 0.887, respectively, and the mean absolute differences were less than 3.5 degrees. The ICC between the computeraided and manual methods for Cobb angle measurements was 0.854, and the mean absolute difference was 3.32 degrees. According to the investigators, these results indicate that the computeraided method demonstrated good reliability for Cobb angle measurement from the chest X-rays.

In addition, using the mean value of Cobb angles in manual measurements above 10 degrees as a reference standard

for scoliosis, the investigators found that the computer-aided method had good accuracy for scoliosis diagnosis on chest X-rays.

Pan and colleagues note that a few previous studies have been conducted for measuring the Cobb angle. For example, a contour and angle-function based methodology was proposed by Bonanni et al as an alternative to the classical vertebra endplate method for determining the Cobb angle. The method was less sensitive to noise and image artefacts because of dependence on the overall spine features.

They also mention that recently, several studies have also attempted to develop computer-aided methods using a deep learning technique. Wu et al, for instance, proposed a multi-view

The computer -aided method had good reliability for Cobb angle measurements.” correlation network (MVC-Net) that allowed automatic assessment of the spinal curvature on anteroposterior and lateral X-ray views through joint multiview input feature learning and explicit reinforcement of reciprocal relationships

between the spinal landmark and Cobb angle. However, the MCV-Net might not be ideally suited for elderly patients with scoliosis, say the authors of this study, because the spinal landmark located in the four vertices of each vertebral body would be varied with the formation of marginal osteophytes.

Zhang et al developed a computeraided method using a deep neural network that still requires manual intervention, such as assignment of vertebral patches, and was therefore “not reliable” to measure Cobb angle for in vivo radiographs, remark Pan and colleagues.

The investigators highlight a few limitations of the present study. Firstly, they note that the cobb angle measured by the computer-aided method was the maximum angle between the superior perpendicular of cranial vertebrae and inferior perpendicular of caudal vertebrae at the longitudinal central line of the vertebral body. When the spinal curves were ≥3, the computer-aided method might occasionally produce an incorrect result, the investigators note.

In addition, the whole spine radiographs were considered as the standard images for scoliosis assessment.

The computer-aided method was needed to be trained and tested on the whole spine radiographs, and, finally, this retrospective study was a preliminary evaluation of the computer-aided method, and a prospective evaluation should be performed in further study.

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November 2019 | Issue 53

Interview

Profile

Margareta Nordin

In a career spanning several decades, Margareta Nordin has gained recognition for her evidence-based approach to spine care. She talks to Spinal News International about how her early career and education has shaped her thinking.

When did you know you wanted to go into research, and what drew you to spine research in particular?

From early on, I was interested in receiving an answer and if I did not believe it or understand it, I started looking for facts. After graduating, my first employment was at the Department of Handicap Research, University of Goteborg, under the late Sven Olof Brattgård.

Under his leadership Sweden changed its view on individuals with disability. The aim of the research was to make people with a handicap self-sufficient through technology, education, innovation, and policies. My interest in spine ailments came later when I realised people with back pain could not perform at work, life quality was hampered and a person with chronic back pain was often miserable. Spine pain causes the largest burden of disability in the world today.

You have a background in physical therapy. How has this been important throughout your career?

I am very grateful for my background as a physical therapist, combining the goals of restoring the patient’s function, educating them, and returning them to full activity. A robust education in musculoskeletal disorders, biomechanics, psychosocial factors, pain behaviours, and teaching the patient how to move was essential in my career. My life changed when I was elected as a rotary fellow. I was one of two individuals chosen from Europe for a stipend and chose the University of Washington in Seattle, USA. My topic was biomechanics of the musculoskeletal system and I wrote my first book in collaboration with Victor H Frankel, professor and chairman at the Department of Orthopaedics. This book is now in its fifth edition and has been translated into 10 languages. After two great years in Seattle I returned to Sweden to complete a Doctorate of Medical Science.

Have you had important mentors throughout your career? What have they taught you?

This is a difficult question as I have worked with so many wonderful people and I still learn every day. My first mentor was my mother—a warm, intelligent, very diplomatic woman who always supported me. From her I learned diplomacy, thoughtfulness, kindness, humour, and that a smile can go further than anger. This has served me well during my career. Another mentor was my thesis director the late Alf N Nachemson, professor and chair at the Department of Orthopaedics, Goteborg University, Sweden. Alf was an incredibly innovative, knowledgeable, honest, and demanding, yet supportive, thesis director. Alf was instrumental in changing the perception of physical therapy in Sweden and today there are eight departments of physiotherapy and more than 300 physical therapists that have a doctorate. In 1984, Victor H Frankel offered me a position to start the Occupational and Industrial Orthopedic Center (OIOC) at the Hospital for Joint Diseases Orthopedic Institute in New York, USA, a very exciting offer that was impossible to refuse. Victor is a formidable mentor and is always positive, creative, and supportive. OIOC specialises in people with spine pain, combining clinic, research, and education with a multidisciplinary team. It

was unusual at the time. My friend Christina Wiktorin (Karolinska Institute, Stockholm, Sweden) is another mentor and is a formidable woman who I can always call and discuss things with. She always challenges me.

What is the main focus of your current research?

My main research focus today is education, translation and implementation of evidence-based care for spine ailments. After I left New York in 2012 and moved to France, I worked with EUROSPINE and World Spine Care (WSC). I was supported to create the EUROSPINE Diploma in Interprofessional Spine Care (EDISC), to promote evidence-based care for spine clinicians.

The first EDISC took place in July 2019 and attracted multidisciplinary participants from 13 countries. It is a very exciting project with a great task force representing 10 countries, co-chaired by the esteemed epidemiologist Pierre Côté. WSC establishes low-cost evidence-based care in communities with little access to affordable spine care, currently serving Botswana, India, Dominican Republic, and Ghana. We set up clinics in remote areas, staffed with physiotherapists or chiropractors with training of evidence-based protocols. It is very rewarding and necessary work.

You have participated in several national and international task forces on spine pain. What have been the most significant results to come out of these?

From 1984 to 2017 I participated in six large task forces in the USA, Canada and France: Agency for Healthcare Policy and Research (AHCPR) Clinical Practice Guidelines for Acute Low Back Problems in Adults; the Quebec Task Force on Whiplash Associated Disorders (WAD); the Paris Task Force on Exercises

We must educate women to acquire leadership skills and create more female leaders.”

Low Back Pain; the Bone and Joint Decade 2000–2010 Task Force on Neck Pain and its Associated Disorders (NPTF); Development of Minor Injury Treatment Protocol Project, Ontario Government; and the Global Spine Care Initiative (GSCI). All these task forces have been published and heavily referenced over the years and changed clinical practice. It takes about 10 years to see the fruit of these efforts, so you must be patient. I feel grateful to have participated in all these taskforces and want to thank all my colleagues for a very busy, sometimes difficult but wonderful time.

You have been the president of several societies over the course of your career, most recently EUROSPINE. What did you achieve in this position?

I have always believed in professional associations and their capacity to deliver education and research on the best evidence in spine care. I was elected the first female

president of the International Society for the Study of the Lumbar Spine (ISSLS) for 1999–2000. When my workload diminished a bit and I moved to France, I was asked and elected as the first female EUROSPINE president for 2016–2017 by Everad Munting. There were only men in the executive and I am not sure what they expected from me, nor was I sure what to do, as I did not expect to be given this honourable position.

However, it was one of my best years, and I was pleased to work with a thoughtful and supportive executive committee. I had three major accomplishments which included the creation of Task Force Research (TFR).

This runs research courses and distributes grants to members. Also the creation of EDISC, a continuous education program for all clinical professions interested in the field of spine care. Finally, increasing the interest in spine ailments from larger institutions such as the World Health Organization (WHO), the European community and national governments in spine disorders.

Issue 53 | November 2019

Interview

11

Fact File

Qualifications

1982 Doctor of Medical Science, Gothenburg, Sweden 1969 Physical Therapist, Gothenburg, Sweden

Professional positions (selected)

Director, Occupational and Industrial Orthopaedic Center, Hospital for Joint Diseases, New York, USA Program Director, Program of Ergonomics and Biomechanics, New York University, New York, USA Professor, research, Departments of Orthopaedic Surgery and Department of Environmental Medicine, New York University, USA President, International Society for the Study of the Lumbar Spine (ISSLS) President, EUROSPINE President, World Spine Care Europe

Memberships (selected)

North American Spine Society (NASS) American Academy of Orthopaedic Surgeons (AAOS) EUROSPINE American Occupational Medical Association (AOMA) International Society for the Study of the Lumbar Spine (ISSLS) Orthopaedic Research Society (ORS) World Spine Care

Awards & Prizes (selected)

There is still a gender disparity among the top researchers in spine. How well do you think institutions are doing in assisting women into following a career in spine, and could this be improved?

There are too few women in top positions. Research tells us that women outperform men in emotional intelligence which is a core trait for those in positions of leadership. Men tend to perform better when the focus is on managing tasks, while women tend to perform better when the focus is on managing people. The gender mix is therefore important. The inclusion of women in leadership positions in both healthcare and research sadly seems to be declining. Institutions and societies have to do more to recruit women and to support them in taking up leadership positions. But that will not be enough on its own. We must educate more women to acquire leadership skills as well as creating many more female mentors.

What advice would you give to someone wishing to start their career in spine research?

Communicate that you want to do research with your colleagues and supervisors, attend conferences and visit departments or groups that do research you are attracted to. If you are a clinician start by taking EUROSPINE research courses. You can also be more ambitious and take a master’s in clinical research or methodology.

Some people cannot live without research—I am one of them—as it gives you many problems and sometimes insomnia but you get friends all over the world and you eventually make a change for the better of your patients or the community.

What are your interests and hobbies outside spine?

Outside of spine I enjoy walking and hiking, reading, cooking, and dogs.

1988 The Volvo Award (Biomechanics), International Society for the Study of the Lumbar Spine (ISSLS) 2001 Grammer European Spine Journal Award, Recovery of impaired muscle function in severe sciatica, Gothenburg, Sweden 2004 Junior Faculty Nobel Forum Lecture, Nobel Forum, Factors predicting delayed recovery in back and neck problems

Publications

Peer reviewed articles: 219 Books: Three.

Are respiratory disorders risk factors for troublesome low-back pain?, European Spine Journal 2019 Evidence-based management of spine pain disorders among underserved people in Navi Mumbai, India: A two-year observation report, Critical Reviews in Physical and Rehabilitation Medicine 2019 The Global Spine Care Initiative: model of care and implementation, European Spine Journal 2018

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November 2019 | Issue 53

Vertebroplasty

Percutaneous vertebroplasty safe and effective only in patients with acute fractures A meta-analysis, recently published in Osteoporosis International, has found that the application of percutaneous vertebroplasty is safe and effective only in patients with acute osteoporotic vertebral compression fractures (OVCFs) having persistent and severe pain.

The investigators recorded no benefits among patients with older fractures or those bearing non-severe symptoms.

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ccording to the authors, S Lou (The First Affiliated Hospital of Harbin Medical University, Heilongjiang, China) and colleagues, OVCFs are common in the elderly population and are often treated using percutaneous vertebroplasty. However, the effectiveness of percutaneous vertebroplasty reported by various randomised controlled trials (RCTs) is inconclusive. This study therefore aimed to analyse, from existing published literature, the efficacy and safety of percutaneous vertebroplasty for OVCFs. Lou and colleagues conducted searches in Medline, EMBASE, and Cochrane Libraries since their respective inceptions on 1 January 2019 for RCTs of OVCFs treated with percutaneous vertebroplasty compared with non-operative treatment.

The primary outcomes were pain relief at one to two weeks, one to three months, and six to 12 months. The secondary outcome was the rate of occurrence of new vertebral fractures, and the meta-

analysis was performed using a random effect model.

The investigators included a total of 12 RCTs, comprising 1,624 patients, in the analysis. For the blinded studies, they found statistical differences between percutaneous vertebroplasty and the sham injection group for the three primary outcomes in the subgroup of the Vertebroplasty for acute painful osteoporotic fractures (VAPOUR) trial.

Although pain scores were similar between the percutaneous vertebroplasty group and the sham injection group for the VAPOUR trial at each period, the effect size of percutaneous vertebroplasty increased over time.

They found that in the open label studies, percutaneous vertebroplasty significantly reduced pain at all the time points, and that the risk of the new vertebral fractures was similar between the percutaneous vertebroplasty groups and control groups.

Due to certain limitations of the

Preventive vertebroplasty effective for the long-term consolidation of vertebral metastases

Preventive vertebroplasty is a longterm, effective means of consolidating vertebral metastases, Frédéric Deschamps (Gustave Roussy Cancer Campus, Villejuif, France) told a spinal interventions free paper session at the annual meeting of the Cardiovascular and Interventional Radiological Society of Europe (CIRSE; 7–11 September, Barcelona, Spain). But the quality of injections matters, suggesting techniques that improve the quantity and quality of cement diffusion with vertebral metastases require development, he said.

THE STUDY AIMED to assess the long-term consolidation of the metastases after the procedure, and to report on the risk factors of pathological fractures despite it having been performed. As the spine is the most common site of bone metastases, Deschamps said, pathological fractures can impact quality of life.

meta-analysis, Lou and colleagues warn that the results should be “interpreted cautiously”. They note, for example, methodological limitations in the quality of the original studies, such as the unclear random method, the unclear concealment of the treatment allocation, and the inadequate blinding.

In addition, the possibility of publication bias might exist because of ongoing and unpublished trials, although no statistical evidence for this was detected.

They also note that while the baseline of pain scores and duration of fracture might be key factors affecting the percutaneous vertebroplasty, there may potentially be other clinically relevant but unreported confounding factors to be considered, such as the types of patients, the degree of bone mineral

Followup longer than 12 months is necessary for further studies to demonstrate the long-term therapeutic effects of percutaneous vertebroplasty.”

To measure tumourrelated instability, the team used the spinal instability neoplastic score (SINS), which totals: location of the metastases, mechanical pain, spinal alignment, bone lesion type, vertebral body collapse, and posterolateral involvement.

With a score of six or lower, there is no Frédéric Deschamps instability, Deschamps said; seven to 12 is considered indeterminate, while 13plus indicates high instability, with surgery required.

“Vertebroplasty is a technique that can be used to restore the vertebral body strength in order to prevent pathological fractures, pain and neurological complications,” Deschamps said. “It consists of the injection of cement in the vertebral body, but also within the metastases.”

Deschamps noted that measurement of cement injection quality involved assessing the cement’s contact with both endplates, a vertebral filling score (Saliou score), and the metastases filling.

The team performed a single-centre, retrospective review of patients who underwent vertebroplasty between January 2005 and January 2016. A total of 573 patients were enrolled, with 473 excluded due to follow-up of less than a year, receiving the procedure for palliation of pathological or osteoporosis fractures as well as for consolidation of benign tumours. Of the 100 included, the mean age was 54, with 61 female patients and 39 male, and the primary cancer was breast (35%).

Researchers tallied 215 vertebral metastases at the time of the procedure (T0): 138 were considered at risk of pathological fracture (treated metastases) and 77 were not considered at risk (untreated metastases). The

density, and the types of percutaneous vertebroplasty techniques. Moreover, owing to the limited studies done to date, whether the baseline of pain scores and duration of fracture truly affect the percutaneous vertebroplasty “still needs to be determined by further trials,” they suggest.

Considering the direction of future research in the field, the investigators suggest that any further studies should “focus more on [patients with acute OVCFs and experiencing severe pain] and use more consistent inclusion criteria”. They suggest, for example, that each study should add the confirmation of OVCFs with magnetic resonance imaging (MRI) to the inclusion criteria and use the same threshold of the baseline scores for patient eligibility.

Lou and colleagues also suggest that, since they determined that the baseline information could affect the effect of percutaneous vertebroplasty, further studies “should clearly report the baseline information, such as the duration of back pain, the baseline pain scores, the methods of non-operative therapy, the PMAA volume, and the baseline T-scores, and other clinically relevant factors, to find the association between these factors and percutaneous vertebroplasty.”

Finally, they indicate that a longer follow-up—more than 12 months—with a large enough sample size is “necessary for further studies to determine the long-term therapeutic effects of percutaneous vertebroplasty”.

metastases’ characteristics were compared using SINS at T0 and the rate of pathologic fracture at one, two and three years between treated and untreated metastases.

Outlining the results, he said: “Despite a lower SINS value at T0 (4.5 vs. 5.8; p<0.001), the rates of pathological fracture at one, two and three years were significantly higher among untreated-vertebral metastases compared to the treated-vertebral metastases (p<0.005). Major risk factors of fracture among treatedvertebral metastases were: SINS value ≥8 (OR: 6.3; p=0.012), mechanical pain (OR: 11.295; p=0.001), osteolytic lesion (OR: 8.280; p=0.033), metastatic vertebral body involvement >50% with no collapse

My personal advice is to perform at least bipedicular access if you want to perform good consolidation.”

(OR: 12.325; p<0.001), Saliou-score <9 (OR: 8.334; p=0.008), vertebral metastasis filling with cement <50% (OR: 7.396; p=0.007), and the absence of cement’s contact with vertebral endplates (OR: 4.876; p=0.014).”

The selection of vertebral metastases can be done based on the SINS value: if the score is eight or higher, he said, vertebroplasty should not be performed.

“You can do it for pain but for consolidation it is not appropriate, and you probably have to discuss consolidation through surgery.”

Deschamps added: “My personal advice is to perform at least bipedicular access if you want to perform good consolidation, and also to consider other techniques such as kyphoplasty or stentoplasty for this purpose.”

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November 2019 | Issue 53

Intraoperative neuromonitoring

The relevance of intraoperative neuromonitoring for spine surgery

Intraoperative neuromonitoring (IONM) was introduced several decades ago and is an increasingly favourable option for delicate surgeries. A recent study1 indicates that IONM procedures have risen 296% from 2008–2014. So, what is it and how does it benefit spine surgery? Jay Jagannathan discusses IONM’s relevance to complex spinal surgeries.

much traction. Preservation of SSEP curves have been shown to predict longterm recovery from spinal cord injury in animals (Neurosurgery. 1987 20 [1] 138–42). In another study, Langeloo et al found that an 80% decrease in SSEP amplitude in one of six recordings had 100% sensitivity and 91% specificity for spinal cord injury (Spine, Phila Pa 1976 2003 May 15;28 (10) 1043–50).

Motor evoked potentials (MEPs) test the integrity of motor pathways that start from the brain. These pathways are relayed to the muscles and extremities via nerves in the cortico-spinal tract and subsequently by peripheral nerves.

Motor neurons can be stimulated directly (D-waves), that reflect direct activation of the motor system, or indirectly (I-waves), that reflect indirect activation of motor neurons via other circuits in the brain. When operating in a region at risk of injury (for example, in a spinal cord tumor), measuring D-waves above the location can provide information on whether the level of transmission from the brain is adequate.

More commonly, in degenerative spine

ONM is the practice of using electrophysiological methods, including electroencephalography (EEG), electromyography (EMG), and evoked potentials to scan and monitor the functionality—as well as integrity— of certain neural structures during a surgical procedure. While IONM has multiple purposes, it can be invaluable in the spinal theatre in reducing risk to a patient’s spinal cord or the central nervous system. IONM requires a team of specialists typically consisting of a surgeon, neuromonitoring technologist, neuromonitoring interpreting physician, anaesthesiologist and surgical team to collaborate during a procedure.

IONM has particular relevance for complex spine procedures. Its use in cervical, thoracic or lumbar procedures, especially those that pose any risk to nerves or the spinal cord, provide critical information to assist in achieving a positive surgical outcome. In extreme cases such as tumour removal, deformity correction or an injury to the spinal cord, IONM should be considered a necessity.

In any neurosurgical procedure with a risk of injury to the nervous system or spinal cord, an extra set of eyes and clear guidance is a welcome addition. Collaboration and trust in working with neuromonitoring is key and begins well before any procedure is scheduled. To understand the importance of neuromonitoring in spine surgery, it is critical to recognise the specific importance of what is being monitored.

Somatosensory evoked potentials (SSEPs) monitor the transmission of sensory impulses to the brain. In spine surgery, this is often measured by providing a small electrical stimulus to a peripheral nerve ending. These impulses are then sent via a complex pathway involving the dorsal columns, the thalamus, and the somatosensory cortex, which is the portion of the brain which receives sensory impulses. In general, somatosensory impulses cross over from

surgery, the transmission of signals at the level of the muscle (the M-wave) is important as it demonstrates integrity of the cortico-spinal-peripheral nerve circuit. Unlike SSEP monitoring, which is continuous, MEP potentials are done at the surgeon’s request, when there is suspicion of injury. In patients with severe pathology, MEPs may be decreased prior to the surgery starting, and often a baseline MEP recording is needed before the operation. Profound drops in MEP may be a sign of neurologic injury.

Unlike SSEP and motor potentials, EMG monitoring measures the integrity of peripheral nerve function and the impulses it relays to the muscles–thus it measures nerve function outside the spinal cord. In EMG monitoring, electrodes are placed in the muscles innervated by a given nerve. Stimulation of intact motor nerves will create a compound motor action potential (CMAP) that indicates stimulation of the muscle innervated by the nerve. In

Jay Jagannathan Comment & Analysis

I

There is no doubt that IONM adds expense to already expensive spinal procedures, but many insurers recognise the benefits.” one side of the body to the other, so impulses received in the left side of the brain are from the right side of the body.

From a surgical perspective, continuous SSEP monitoring provides the surgeon with a general assurance of the integrity of the peripheral nerve/ central nervous system circuit. Changes in SSEPs may be seen in a variety of situations—the initial movement of patients in unstable spinal cord injuries, during surgical manipulation around the spinal cord, when an extremity is not positioned properly and during circumstances such as excessive blood loss or drops in blood pressure. Each of these conditions require specific treatments. For example, if SSEP potentials alert when a spinal cord tumour is removed, it is often necessary to raise blood pressure, and in some instances steroid medications may be indicated. In other cases, changes in potentials may be addressed by doing something as simple as repositioning an extremity which may be under too

addition to confirming the presence of a nerve (useful in lateral, transpsoas approaches where the nerve may be hidden in muscle), a train of EMG during decompression or placement of a cage may be a signal of nerve compression or injury and may require the surgeon to reconsider the extent of the decompression or the size of the cage being placed.

Typically, there are two types of EMG recordings, including free-running EMG, which is performed through the duration of an operation and provided second-by-second monitoring of the nerve function. Triggered EMG measures muscle contraction after stimulation on or around a nerve. Triggered EMG has been described in placement of pedicle screws in spinal surgery, although its utility in these cases is controversial.

There is some industry debate among spine surgeons on when to utilise IONM on patients. While it is now widely accepted that there are benefits in achieving positive surgical outcomes, some dismiss the need for this advanced surgical approach among simpler procedures such as routine laminectomies or microdiscectomies.

There is no doubt that IONM adds expense to already expensive spinal procedures, but many insurers recognise the benefits. The reduced surgical injury risk coupled with quicker patient recovery are a bonus, not to mention the avoidance of a potential malpractice claim. IONM’s growing popularity can be noted in the steady increase of cases, which one study2 tracked at 1% of all spine procedures in 2007, to 12% of all cases by 2011.

If IONM is to continue growing in popularity and acceptance in the spine surgery theatre, there will need to be more training on its indications and limitations. The cohesiveness of the IONM team from surgeon to anaesthesia to monitoring is also critical. In the future, it is believed that applications of IONM will have benefits in the operating room, but also in on-site trauma and intensive care units. The potential benefits of applying remote monitoring techniques to the critically injured can greatly impact the level of knowledge and approach to spinal assessment and care prior to the surgical environment.

For further information, research and advocacy, please visit the American Society of Neurophysiological Monitoring (ASNM), a nonprofit dedicated to advancing industry interest in the practice.

Jay Jagannathan is a neurosurgeon specialising in cranial and spinal surgery at Jagannathan Neurosurgery (Michigan, USA).

References 1. Journal of Spine Surgery. (2018). Utilization of intraoperative neuromonitoring throughout the United States over a recent decade: an analysis of the nationwide inpatient sample. Retrieved from: https:// www.ncbi.nlm.nih.gov/pubmed/30069509. Accessed [publishing date] 2. Neurosurgery Focus. (Nov. 2014). A socioeconomic analysis of intraoperative neurophysiological monitoring during spine surgery: national use, regional variation, and patient outcomes. Retrieved from: https://www. ncbi.nlm.nih.gov/pubmed/25363427. Accessed [publishing date]

Issue 53 | November 2019

Oral TXA is as good as IV at reducing blood loss in spinal fusion surgery Intravenous (IV) and oral tranexamic acid (TXA) are equivalent at reducing blood loss following thoracolumbar spinal fusion, a phase II prospective randomised trial has found. Researchers suggest oral administration is a viable and more costeffective alternative to IV in spine surgery.

CHARLES YU (HENRY Ford Hospital, Detroit, USA) presented the findings at the North American Spine Society Annual Meeting (NASS 2019; 25–28 September, Chicago, USA), telling delegates: “Oral TXA is equivalent to IV TXA in preventing blood loss and haemoglobin drop in spinal fusion surgery. We did not find a significant difference in drain output, postoperative transfusion rates, thromboembolic events, or infections when using IV versus oral TXA.” TXA is a synthetic antifibrinolytic agent that prevents fibrin breakdown by binding to plasminogen, stabilising the fibrin clot. Intraoperative use has been shown to reduce blood loss and the need for transfusions after spinal fusion surgery.

Yu explained: “There have been a number of randomised controlled trials in the past comparing IV TXA to placebo. A meta-analysis of 411 patients found a significant reduction in blood loss and blood transfusion rates in patients receiving IV TXA. And none of these patients in this cohort had a postoperative thromboembolic event. TXA has also been proven to be efficacious for patients in the paediatric population.”

Conference coverage TXA can be administered orally, topically, or intravenously. Costs for IV administration vary from US$47–108 per dose, depending on the formulation.

“And that is prior to the fee that the pharmacy charges for formulating the drug,” Yu added. “Oral TXA offers an alternatively cheaper and easier route of administration than intravenous. There are currently no prospective studies investigating the equivalence between IV and oral TXA in patients undergoing spinal fusion surgery, and that is the question that we set out to answer.”

In all, 216 patients were randomised to either IV TXA (n=111), or to oral TXA (n=105). Participants in the oral TXA cohort received 1,950mg as three tablets two hours before incision. Patients on IV TXA received 1g bolus before incision and another 1g before closure.

Two surgeons were involved in the study, one of whom performed 95% of procedures. Fifty three percent of the cases were revisions. No patients in either cohort were lost to follow up, and no interventions were discontinued.

Among the exclusion criteria were a known allergy to TXA, a history of renal failure or kidney transplant, or a history of an antithromboembolic event, such as a myocardial infarction or stroke, in the previous year.

“There were significant differences in weight, BMI [body mass index], number of interbody fusions, and preoperative platelet count between the IV and the oral groups,” Yu pointed out, “with the IV group being significantly lower weight and having lower BMI.” There were no significant differences between the two groups on intraoperative measures, such as anaesthesia, surgical time, estimated blood loss, and IV fluids. There were eight (7%) transfusions in the IV group and three (3%) in the oral cohort.

Yu and colleagues found that haemoglobin decreased by 3.56g/dl

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among the IV cohort compared with 3.19g/dl in the oral group (p=0.002); haematocrit reduction was 10.5% for IV patients versus 9.7% for oral patients (p=0.001). And calculated blood loss was 1,270mls versus 1,206mls for IV and oral patients, respectively.

Yu clarified: “These were calculated using a [Welch] two one-sided test, which is a test of equivalence and, with that test, a p-value of <0.05 signifies equivalence.

Those values are equivalent between the two groups.”

The remainder of the outcomes—drain output, rates of postoperative transfusion, thromboembolic events, infection, and length of hospital stay—were compared using a t-test, “and there was no significant difference in those outcomes between the two groups,” he reported.

“This is the first study to our knowledge comparing oral and IV TXA in thoracolumbar fusion. The use of oral TXA in spinal fusion surgery has the potential for substantial cost savings.”

Limitations of the study include the variety of patient diagnosis and surgical techniques that were used, and that haemoglobin was calculated based on lowest recorded postoperative level which could have been affected by haemodilution. And, as it was assumed that oral TXA was superior to placebo, a placebo group was not included.

Yu confirmed that the trial is ongoing, and investigators are collecting more patients in order to perform adequately powered subgroup analyses, based on the number of levels fused. Current enrolment consists of 140 patients with 1–2 levels fused, 62 with 3–5 levels, and 45 patients with >5 levels fused. “We did a subgroup analysis on the 1–2 level group and we found that oral is equivalent to IV in this group as well.”

Charles Yu

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November 2019 | Issue 53

Market watch

Clinical News DiscGenics announces publication of preclinical data for disc degeneration treatment

DiscGenics recently announced the online publication of a study in The Spine Journal summarising the results of pre-clinical testing for discogenic cells, which are used in DiscGenics’ investigational cell therapy for disc degeneration (IDCT).

The paper, titled “In vitro and in vivo evaluation of discogenic cells, an investigational cell therapy for disc degeneration”, demonstrates that

Discgenics IDCT injection

intradiscal injection of discogenic cells may be a viable treatment for human degenerative disc disease (DDD), citing that the cells produce extracellular matrix that may rebuild the depleting tissue within degenerative discs, and pose no significant safety concerns.

Discogenic cells are biomedically engineered progenitor cells derived from donated adult human intervertebral disc tissue to address the degenerated disc. IDCT is an injectable therapy that utilises discogenic cells, and is seen as a potential non-surgical solution for patients suffering from DDD. The objective of the studies presented was to evaluate the characteristics, mode of action, and in vivo efficacy and safety of discogenic cells before human clinical testing. Discogenic cells generated from different adult human donors were evaluated in vitro for surface marker expression profile, matrix deposition, and tumorigenic potential. Then, in vivo characterisation of discogenic cells was performed through subcutaneous implantation and intradiscal injection of human discogenic cells in nude mice and rabbit disc degeneration models, respectively.

“Our preclinical experience with discogenic cells was very compelling, as it indicated the ability of IDCT to safely normalise disc architecture and restore disc height in animal models,” commented Flagg Flanagan, CEO and chairman of the board of directors for DiscGenics. “If IDCT demonstrates similar results in humans, we believe the outcome could be a reduction in pain and disability, potentially revolutionising the way millions of patients suffering from the debilitating effects of chronic low back pain are treated.”

Product News ControlRad announces first clinical use of Trace radiation reduction technology

ControlRad has announced the first clinical use of the ControlRad Trace system following its clearance by the US Food and Drug Administration.

The initial procedures were performed at Niagara Falls Memorial Medical Center (Niagara Falls, USA) by Andrew Cappuccino, an orthopaedic surgeon specialising in minimally invasive spine surgery.

“The ControlRad Trace system exceeded my expectations in reducing my radiation exposure, as well as the exposure to my patient and to my operating room team,” Cappuccino said. “There was no interruption of my normal workflow and zero loss to my image quality in the area where I was focused. As a surgeon who was diagnosed with leukemia after many years of performing fluoroscopicallyguided, minimally-invasive spine procedures, I believe ControlRad Trace to be groundbreaking and one of the most important safety innovations that has been brought to market during my tenure as a surgeon.”

“We are extremely pleased that the ControlRad Trace system is now being used clinically, seamlessly reducing radiation exposure to the patient and to the operating room team,” Guillaume Bailliard, ControlRad chief executive officer commented. “It is humbling to be able to play a valuable role in providing a safer environment to the medical staff who are day-in, day-out putting themselves in harm’s way in order to treat their patients.”

Fluoroscopically-guided procedures with C-arms have allowed for major advances in treating countless diseases; however, they expose patients and medical staff to ionising radiation, which may increase a person’s lifetime risk of developing cancer.

The ControlRad Trace solution is the only technology that can be integrated into existing mobile C-arms to reduce radiation in any fluoroscopically-guided procedure, ControlRad said in a press release. Additionally, the ControlRad Trace system reduces radiation exposure by up to 89%, protecting patients and medical staff without compromising image quality or workflow, the company added.

With its proprietary semi-transparent filter, tablet, and image processing technology, the ControlRad Trace solution can be retrofitted to an existing C-arm, reducing the barrier to adopting the technology. To use the technology, the medical staff draws a region of interest on a ControlRad tablet, which in real-time optimises image quality in the region of interest as well as reducing exposure to unnecessary radiation in the periphery.

Brainlab introduces Loop-X mobile intraoperative imaging robot

Brainlab unveiled Loop-X, the first mobile intraoperative imaging robot, at NASS 2019 (34th Annual North American Spine Society Meeting; 25–28 September, Chicago, USA).

According to a press release, the Loop-X robotic architecture introduces a new standard in flexibility, adding additional degrees of freedom to any surgical procedure. By automating imaging workflow steps and robotically moving with the procedure and on command, the system is in sync with other devices like robotic arms and with the surgeon and staff.

The non-isocentric movement and collimation capabilities allow for the imaging of structures that are much larger—for example in diameter—and much smaller—reducing radiation exposure—than what is possible with the typical CT or 3D C-arm. The device is designed for 2D and 3D imaging, combining ultra-high resolution with extra-low doses, and proprietary technology to image with interlaced energies for soft-tissue visualisation.

“For Brainlab, Loop-X is a critical milestone in contributing disruptive innovations in spinal surgery,” said Stefan Vilsmeier, president and chief executive officer, Brainlab. “It provides us with an even stronger foundation for leveraging emerging technologies such as artificial intelligence, big data, cloud computing, augmented reality, and spatial computing.”

DePuy Synthes launch 3D printed implant portfolio for spine surgery

DePuy Synthes has launched the Conduit interbody platform with Emerging Implant Technologies’ cellular titanium technology product portfolio, expanding its offering for the treatment of degenerative spine disease.

The 3D-printed titanium interbody implants for spinal fusion surgery are

DePuy Synthes Conduit interbody platform

designed to mimic natural bone and facilitate spinal fusion.

During spinal fusion, a degenerated, collapsed disc is removed and replaced with an interbody spacer along with bone graft with the goal of restoring natural height and alignment between two vertebrae. The concept is to replace the former mobile disc space between two vertebrae with an interbody

spacer so that the segment fuses as a single, solid bone. As they are 3D printed, Conduit implants are 80% porous—bringing a differentiated cellular structure designed to mimic the properties of bone and assist with intraand postoperative visualisation, DePuy Synthes said. The cellular structure has a modulus of elasticity, or change in stiffness, similar to bone. All of these characteristics aim to help facilitate bone fusion.

“Our goal as a spine business is to focus on the areas with the most potential to solve unmet clinical needs, and we are excited to add advanced materials to our interbody portfolio as another option for surgeons,” said Nadav Tomer, worldwide president, Spine, DePuy Synthes.

Synaptive offers Modus V surgical microscope to spine market Synaptive Medical will offer its robotic surgical microscope, Modus V, to the spine market as part of an expanded marketing agreement with Stryker.

Synaptive’s initial product offering, the BrightMatter suite of products, is focused on enabling surgeons to perform less invasive, patient-specific approaches in complex cranial procedures such as tumour or stroke. A high-power visualisation tool, Modus V’s robotic arm moves automatically based on the positions of tracked surgical instruments, which enable surgeons to operate continuously without removing their hands from the operative field to adjust the microscope.

Critical to this push into the spine market is the company’s expansion of a co marketing agreement with Stryker.

Originally focused on Synaptive’s surgical planning technology, BrightMatter Plan, the expansion will provide surgeons with broader access to a tool for visualisation in minimally invasive surgery (MIS) approaches in spinal procedures, Synaptive Medical said in a press release.

Synaptive’s director of surgical product management, Brad Fernald, said: “Modus V lends significant assistance to surgeons as they approach complex procedures through minimally invasive approaches, which lead to faster recovery times and less trauma for patients. The combination of our technology with Stryker’s navigation, instruments, and implants equips surgeons with the tools necessary to perform these complex procedures more efficiently and with greater confidence.

Expanding our comarketing agreement from BrightMatter Plan to include Modus V and our new version of auto segmented tractography software, Modus Plan, allows our team to work with Stryker to make these tools available to a much broader audience of both cranial and spinal surgeons.”

Issue 53 | November 2019

Market watch

Industry News Omar Ishrak to step down as Medtronic CEO next year

Omar Ishrak, Medtronic’s chairman and CEO, is to retire on 26 April 2020, following the end of the company’s current fiscal year. Also, the Medtronic board of directors has announced key leadership appointments as part of its leadership succession planning process.

The board of directors has unanimously appointed Geoff Martha, currently executive vice president (EVP) of the company’s Restorative Therapies Group (RTG), to assume the newly created role of Medtronic president and become a member of the board of directors. He will also succeed Ishrak as Medtronic CEO. As president, Martha will lead Medtronic’s operating groups and regions. Brett Wall, president of Medtronic’s Brain Therapies division, was appointed EVP and group president of RTG, succeeding Martha.

At the start of Medtronic’s next fiscal year, Ishrak will assume a new position of executive chairman. He will provide counsel and guidance to Medtronic’s leadership, oversee CEO succession, and drive the ongoing successful execution of Medtronic’s long-term strategic plan.

Ishrak commented: “We have announced leadership changes that meet both the board’s objective of

executing a thoughtful leadership transition, as well as my personal desire to begin transitioning my duties as CEO to a new leader coinciding with the start of our next fiscal year. This plan and its timing enable Geoff and I to partner on achieving Medtronic’s key financial performance goals, as well as delivering on our critical pipeline milestones, including several important product launches. Leading Medtronic as CEO is an honour and a privilege, and I know that Geoff is the right leader to take Medtronic to the next level of its growth and evolution.

Geoff is a results-oriented, dynamic, and innovative business leader who is passionately committed to our mission, the advancement of our growth strategy and the development and diversity of our people. I am confident he has the right track record, commitment, vision, and judgment to lead our company.”

Stryker completes acquisition of Mobius Imaging

Stryker has completed the acquisition of Mobius Imaging and its sister company, GYS Tech, which trades as Cardan Robotics.

The acquisition was agreed in September as an all cash transaction of

approximately US$370 million upfront and up to US$130 million of contingent payments associated with development and commercial milestones. In a press statement, Stryker said that the deal would give its spine division immediate entry into the intraoperative imaging segment and align with its implant and navigation offerings.

Mobius Imaging was founded in 2008, and develops point-of-care imaging technology, which includes the Airo TruCT mobile CT imaging system.

Cardan Robotics, founded in 2015, is working to develop robotics and navigation technology systems for surgical and interventional radiology procedures.

Spencer Stiles, Stryker’s group president, Orthopaedics and Spine, said: “Mobius Imaging and Cardan Robotics bring expertise in advanced imaging and robotics, as well as a robust product pipeline, that will provide Stryker the opportunity to increase its presence in orthopaedics, spine and neurotechnology.”

GTX Medical and NeuroRecovery Technologies announce merger

GTX Medical and NeuroRecovery Technologies (NRT) have announced a merger. The merged entity will be known as GTX medical BV, and will develop neuromodulation therapies to aid functional recovery in people with spinal cord injuries..

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The merged company is developing targeted epidural spine stimulation (TESS), an implantable spinal cord stimulation system with real-time motion feedback. The system is in late-stage development and has been shown to restore locomotion in a select number of patients with spinal cord injury, the companies said in a press release. A second, non-invasive product offering—transcutaneous spinal cord stimulation (tSCS)—is being developed to restore upper limb movement and hand function.

“People with spinal cord injuries deserve a dedicated and coordinated effort of scientists, clinicians and entrepreneurs to bring to market new therapies and products to improve functional outcomes and quality of life,” said Sjaak Deckers, CEO of GTX. “Neurostimulation represents the single biggest breakthrough ever in creating dramatic functional recovery in patients living with spinal cord injuries,” commented Jay Shepard, board member of NRT. The Christopher & Dana Reeve Foundation, the North American non-profit organisation dedicated to curing spinal cord injury by advancing research and improving quality of life for people living with paralysis, will be a shareholder in the merged company, alongside current investors including LSP, Inkef, Wellington Partners, and GIMV. Ian Curtis, board member of the Reeve Foundation, will join the board of directors.

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November 2019 | Issue 53

Market insights

Medtronic continues to show faith in rhBMP-2 despite past controversies The US Food and Drug Administration (FDA) has approved a new prospective, randomised clinical trial evaluating the use of recombinant human bone morphogenetic protein-2 (rhBMP-2, Infuse, Medtronic) during transforaminal lumbar interbody fusion (TLIF) procedures. The study is part of Medtronic’s long-term, global clinical trial programme evaluating the safety and efficacy of the product in both TLIF and posterolateral fusion (PLF) surgeries. However, previous industry-sponsored studies of Infuse were heavily criticised for, allegedly, under reporting adverse events and for being biased.

A MEDTRONIC PRESS release reports that rhBMP-2, the key ingredient of Infuse, is “a manufactured version of a protein already present in the body that promotes new bone growth”. It adds that the product is applied to an absorbable collagen sponge that is used as a carrier to deliver the rhBMP-2 to the implant site and “acts a scaffold for the formation of new bone and it will resorb, or disappear over time”. FDA approved since 2002, Infuse can be used with certain interbody fusion devices for the management of singlelevel degenerative disc disease. It is designed to eliminate the need for an iliac crest bone graft (ICBG).

On the FDA approval for the trial, the principal investigator Joseph D Smucker (Indiana Spine Group, Carmel, USA) commented: “The potential to expand the indications for use of Infuse in posterior spine procedures may give a broader group of patients access to this novel biologic technology. When considering the patient, site, and procedures, Infuse can be a powerful option in a spine surgeon’s armamentarium. This study has the potential to add to the broader clinical and scientific evidence regarding the use of Infuse, and may allow surgeons to better understand its safe and effective use in TLIF procedures.”

Past criticism

After Infuse received FDA approval, concerns about adverse events (specifically, a possible increased risk of cancer) with the product started to emerge. In 2011, The Spine Journal (the official journal of the North American Spine Society; NASS) dedicated an entire issue to a heavily critical review of the product. In one article, Eugene Carragee (Department of Orthopedic Surgery, Stanford Medicine Outpatient Center, Stanford University School of Medicine, Stanford, USA) and colleagues claimed that the industry-sponsored studies had underestimated adverse events with Infuse. More importantly, they observed that the authors of the industry-sponsored studies had financial interests with Medtronic and these interests may have led to bias.

The criticisms prompted Medtronic to ask the Yale University Open Data (YODA) access project to conduct an independent review of the patientlevel data of Infuse. Speaking at a NASS symposium on biologics, held the day before Medtronic issued a press release about the FDA approval for the TLIF trial, Peter G Whang (Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, USA) reported that the YODA review indicated that “there was no evidence of a clinically significant difference

between rhBMP-2 and ICBG for inducing spinal fusion”. He added that these findings also showed that the rate of complications with Infuse was similar to ICBG for anterior lumbar interbody fusion (ALIF) and PLF but were increased with anterior cervical fusion. Whang, who did not participate in the YODA reviews, said his interpretation of the data was that while Infuse should not be routinely used for anterior cervical fusion (ACF), using it as an alternative to ICBG for ALIF or PLF “may be reasonable”.

Regarding a link to cancer with Infuse, he noted that YODA showed that the “absolute risk is small and no longer apparent at four years”.

Current views on Infuse

At the NASS symposium, Gregory D Schroeder (Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, USA) looked at data for Infuse post YODA, noting that more than 650 studies have been published in the six years since the review (with 80 this year alone). According to Schroeder, a plus and a minus of these studies were that they were predominantly independent. Therefore, he said, the “literature is less tainted by industry but there are lower quality studies”. “I think

rhBMP-2 does get the bones to heal. It is probably not needed in routine cases but should be considered for deformity cases. Post YODA, the data show no real evidence for an increased risk of cancer,” he concluded.

Wellington Hsu (Department of Orthopaedic Surgery, Northwestern University Feinberg School of Medicine, Chicago, USA) also spoke at the symposium, reviewing the use of Infuse in clinical practice today. He said: “Our current level of information [for rhBMP-2] is as good as it gets.

We are not going to have an increase in data that will dramatically help our understanding of what is going on [in terms of overall safety and efficacy rather than the applications of the product].” According Hsu, in future, both zealously and fear should be avoided when looking at new spinal technologies.

The Medtronic press release reports that the TLIF trial could potentially enrol more than 1,000 patients. A Medtronicsponsored PLF study received FDA approval two years ago.

N.B. The NASS symposium was held during the 2019 NASS annual meeting (25–28 September, Chicago, USA).

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Calendar of events 6–7 December 5th Annual International Spinal Deformity Symposium (ISDS) New York, USA broad-water.com/isds2019

23–26 January Spine: Base to Summit Vail, USA www.broadwater.com/event/ spine-base-to-summit-2020/

30 January–1 February Annual Symposium on Current Concepts in Spinal Disorders Las Vegas, USA cedars.cloud-cme.com

26–28 February ISASS20 – 20th Annual Conference San Juan, Puerto Rico, USA

26–29 February Canadian Spine Society Annual Scientific Conference 2020 Whistler, Canada

eventscribe.com/2020/

spinecanada.ca

ISASS20

1–3 April Britspine 2020 Glasgow, UK ukssb.com/glasgow2020

1–4 April IMAST 2020 Athens, Greece srs.org/imast2020

27 April–1 May SpineWeek 2020 Melbourne, Australia www.spineweek.org

30 April–1 May EUROSPINE Spring Speciality Meeting Frankfurt, Germany eurospine.org

29 July–1 August NASS Summer Spine Meeting Bangkok, Thailand spine.org/ssm