Spinal News International 54 – March 2020 US Edition

March 2020 | Issue 54

“Starker than expected” radiation from fluoroscopy in TLIF surgery A study of radiation exposure among patients undergoing transforaminal lateral interbody fusion (TLIF) surgery presents a “starker than expected” difference in dosage between patients having intraoperative fluoroscopy-guided procedures than those aided by imageguided navigation (IGN) or robotic assistance.

T

he findings should raise concerns about the proportion of total radiation dose applied to surgeons and operating staff, the researchers at New York Langone Medical Center (New York, USA) say. Published in the Global Spine Journal, the retrospective study carried out by Erik Wang, Aaron J Buckland, and colleagues sought to assess patient radiation exposure and perioperative outcomes from the use of IGN and robotic assistance in one- or two-level TLIF surgeries. According to the research team, the study is the first to assess this relationship across IGN, robotic assistance, fluoroscopically-guided minimally invasive surgery (fluoro-MIS), and open TLIF. Discussing the findings with Spinal News International, Buckland says: “We were a little surprised at just how much radiation dosage there was just from fluoroscopy. That is only to the patient, let alone what we are seeing as staff. It was a little alarming from that standpoint, especially when a lot of the surgeons doing minimally invasive surgery using fluoroscopy are younger surgeons with their whole career ahead of them, it really does start to raise some serious questions about the way you are going to practice in the next 30 years.”

Writing in the study, Wang and Buckland noted that dosimetry readings during fluoroscopicallyguided spinal surgery have been shown to be 10 to 12 times greater than those in non-spine orthopaedic procedures, based on measured fluoroscopy times.

We were surprised at how much radiation there was just from fluoroscopy.”

Several studies have raised concerns over radiation exposure with both robotic assistance and IGN, particularly in weighing the reduction of intraoperative radiation exposure to operative staff against potentially increased exposure to the patient. The study suggests that radiation exposure for spine surgeons using conventional fluoroscopy may approach or exceed the annual cumulative exposure acceptable for established lifetime dose equivalent limits.

In the study paper, Wang and Buckland write that as rates of lumbar spinal instrumentation and minimally invasive surgery (MIS) continue to increase, methods to improve accuracy and reduce radiation burden have also adapted.

Two-dimensional fluoroscopic navigation has been a mainstay of multiple medical disciplines since gaining popularity in the 1980s, the study team write, adding that technologies such as robotic navigational guidance and intraoperative computed tomography (CT) IGN have increasingly been used to improve the accuracy of pedicle screw positioning and patient safety. However, concern has been raised regarding the potential increased radiation dose to the patient as a result of requiring a CT scan.

Wang, Buckland and colleagues assessed the relative radiation exposure in each of the selected techniques, undertaking a retrospective review of all adult patients (≥18 years) undergoing one- or two-level TLIF at their institution between January– December 2018. Patients were grouped by type of Continued on page 2

Steven Glassman: BMP in spinal surgery

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Alex Vaccaro:

Profile

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ISASS meeting hears results from PEEK cervical disc IDE The use of a polyetheretherketone (PEEK) cervical disc allows for significantly improved visualisation of surrounding spinal and neuro structures on postoperative magnetic resonance imaging (MRI) scans compared to metal implants. This is according to results presented by Domagoj Coric (Carolina Neurosurgery & Spine Associates, Charlotte, USA) at the International Society for the Advancement of Spine Surgery Annual Meeting (ISASS; 26–28 February, Puerto Rico, USA).

CORIC PRESENTED results from the first investigational device exemption (IDE) trial to assess a PEEK-ceramic cervical disc arthroplasty (CDA) implant, the Simplify Disc (Simplify Medical), which compared MRI artefacts from the investigational device to that of four CDA devices that are currently on the market.

Coric said that the presence of significant metallic components in existing CDA devices leads to MRI artefacts which can obstruct important anatomy including the neural foramen and spinal cord, causing potential difficulties in postoperative diagnosis.

Spinal implants comprised of PEEK have gained favour, he said, in part due to the reduced MRI artefacts. The first PEEK/ceramic CDA is currently undergoing US Food and Drug Administration (FDA) Continued on page 3 0

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March 2020 | Issue 54

Top stories

Radiation exposure “starker than expected” from fluoroscopy in TLIF surgery Continued from page 1

guidance used for pedicle screw insertion, which were: intraoperative CT IGN, robotic assistance, fluoro-MIS, and open surgery. Procedures carried out by 19 surgeons were involved in the study.

The robotic guidance system used was the ExcelsiusGPS system (Globus Medical), which was used for open and mini-open cases, as well as MIS cases in lieu of conventional fluoroscopic guidance. The IGN system was an Airo mobile intraoperative CT scanner (BrainLab) which was used for open instrumented cases.

A total of 165 patients underwent one- or two-level TLIF during the study period (51.83% female). The mean age was 59.13±13.18 years, BMI was 29.43±6.72 kg/m2, and CCI 1.20±1.56. Twelve cases utilised intraoperative CT IGN for pedicle screw placement and 62 used robotic assistance.

In all, 56 cases were open and 35 were fluoroscopically-guided MIS. The open (38.18% female) and fluoro-MIS (45.71% female) patient groups had a lower proportion of females compared with the IGN (66.67% female) and robotic (64.52% female) patient groups (p=0.021).

In terms of perioperative outcomes, fluoro-MIS group had the lowest mean posterior levels fused (1.06 levels in MIS vs. 1.42 in IGN, 1.27 in robotic, and 1.32 in open; p=0.015), although estimated blood loss was significantly lower in the MIS group compared with all others (162.14 vs. 441.67mL in IGN, 380.24mL in robotic, and 355.36mL in open, p=0.002). Operative time was found to be highest for IGN patients (303.5 minutes IGN vs. 264.85 minutes robotic, 229.91 minutes open, and 213.43 minutes MIS, p<0.001). There were found to be no significant differences in postoperative complications among any of the groups (p=0.644).

Looking at the total procedure radiation exposure among the different methods, the study team found that this was highest in the fluoro-MIS group (82.02±56.24mGy), followed by the robotics (59.84±32.48mGy), IGN (50.21±22.84mGy) and open (22.56±22.62) groups (p<0.001). Total-procedure radiation per level fused was also highest in the MIS group.

In discussing the findings, Wang and Buckland describe the contrast in radiation dosage exposure between the MIS group and the IGN and robotic groups as “starker than one may expect”. They noted: “Mean total-procedure radiation for the MIS cohort

was 82.02mGy compared with 50.21mGy and 59.84mGy in the IGN and robotic groups, respectively (p<0.001).

The MIS patients also had the fewest number of levels fused on average, so the difference was more Erik Wang apparent when calculating total-procedure radiation per level (79.41mGy for MIS vs. 41.88mGy for IGN and 51.18mGy for robotic; P>0.001). Despite the MIS patients having by far the lowest rate of preoperative CT, which adds approximately 20mGy of radiation to the total-procedure sum, they were still exposed to substantially more radiation overall.”

The study team write that while the aforementioned radiation measurements are for the patient, as this radiation dose total stemmed primarily from intraoperative fluoroscopy in MIS cases, “it raises concerns about the proportion of total radiation dose applied to the surgeon and operating staff, who are performing these surgeries on a regular basis”.

Buckland added, however, that he does not believe the findings suggest robotics and navigation are “definitively the answer” when compared against fluoroscopy in all cases. He said: “It is not just about

What sort of increased cost are we using to reduce radiation dose?” radiation dose, but trying to work out the safety and efficacy of robotics and navigation because that still remains somewhat controversial. There are other tradeoffs with these modern modalities, they take increased time in the operating room, there is extra capital cost associated with it, so it is a difficult formula here to work out where the value lies. What sort of increased cost are we using to reduce radiation dose and what does that mean to patient and OR staff safety? It is still unanswered, certainly the radiation piece seems to be in favour of robotics and navigation for minimally invasive procedures at least, the efficacy and safety of these modalities we are yet to definitively prove.”

The study team acknowledged that the sample size, as well as that the fact that procedures in different groups were not all performed by the same surgical team proved to be limitations of the research, and added that a multicentre study would potentially address these issues.

News in brief

The latest stories from the spinal world

n LAWRENCE LENKE INTERVIEW: Lawrence Lenke, the man behind the Lenke Classification System, talks to Spinal News International about how surgeons are adapting to the evolving influence of technology such as 3D imaging, robotics, and artificial intelligence in the field of spinal surgery. He also discusses the increasing trend towards subspecialisation within spinal surgery and considers how this could impact practice in future.

For more on this story go to page 4. n ALEX VACCARO IN PROFILE: The immediate past president of the Cervical Spine Research Society (CSRS), Alex Vaccaro, looks back at his career in spinal surgery. He reflects on his early years in the field, how it has evolved since he began practicing, and considers how advances in minimally invasive surgery have changed approaches to spine care. Vaccaro also offers his advice to those starting out a career in spinal surgery.

in

For more on this story go to page 8. n HOW TECHNOLOGY WILL IMPACT SPINAL SURGERY THROUGHOUT THE NEXT DECADE: Spinal News International takes a look at some of the developments in technology that are likely to impact spinal surgery throughout the course of the 2020s. This includes advances in robotics, artificial intelligence and 3D navigation, the continued evolution of minimally invasive surgical techniques, and 3D printed spinal implants.

For more on this story go to page 10.

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Issue 54 | March 2020

Top stories

ISASS meeting hears results from PEEK cervical disc IDE Continued from page 1

IDE trials, and comparison of MRI artefacts between different CDA devices has not been previously reported in the literature, Coric noted.

The results indicate that the PEEK devices produce statistically smaller MRI artefacts in comparison to other approved devices composed of titanium and polyurethane, titanium and ultrahigh molecular weight polyethylene (UHWMPE), cobalt-chromium molybdenum (CCM) and UHMWPE, or a Ti-ceramic composite. The study team carried out a retrospective review of patients that received a CDA device at one or two contiguous levels and a postoperative MRI from three centres participating in the PEEK/ceramic CDA device IDE trials.

MRIs were performed on 1.5T MRI machines and included axial T1weighted, axial T2-weighted, sagittal STIR, sagittal T1-weighted, and sagittal T2-weighted views. The artefacts were measured by a radiologist blinded to the CDA device. An artefact was defined as the distance between the device boundary and the fringe of the artefact in the anterior-posterior (AP) direction (ASTM F2119); calculated as half the difference between the maximum measured AP distance of the artefact

minus the AP footprint of the device.

A total of 46 CDA devices comprised of titanium/polyurethane (five levels), titanium/UHMWPE (10 levels), CCM/UHMWPE (15 levels), titanium ceramic composite (five levels), and the investigational PEEK/ ceramic composition (11 levels) were evaluated. The investigational device’s artefacts, Coric said, were statistically significantly smaller (p<0.05) than those of other evaluated devices, measuring at ≤0.8mm compared to a range of 3.2–6.3mm for the other devices.

Richard Guyer

endplates with a plastic core or some metal-on-metal devices. Guyer added that while there are multiple prospective studies reporting on one-level TDR, there is much less prospective data available for two-level procedures.

The results presented by Guyer came from three of the 18 sites in the USA

Spinal implants comprised of PEEK have gained favour due to reduced MRI artefacts.”

Further results from the IDE study were presented at ISASS by Richard Guyer (Texas Back Institute, Plano, USA), who investigated the clinical outcomes of two-level cervical total disc replacement (TDR) using the Simplify cervical disc.

During his presentation, Guyer noted that, to date, good results have been reported for a variety of cervical TDRs, which have comprised of metallic

participating in the IDE study for the PEEK-on-ceramic TDR for two-level cervical disc generation. In total, 62 patients were implanted with the device, and 12-month follow-up data were available for this study sample. Outcome measures assessed included the Neck Disability Index (NDI), visual analogue scales (VAS) separately assessing neck and arm pain, and disc height of the operated segments measured from

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radiographs, analysed by an independent lab specialising in image assessment.

Evaluations were conducted prior to surgery and at six weeks, and three, six, and 12 months after surgery.

Outlining the results, Guyer noted that there were decreases (p<0.01) in NDI at 12 months (n=62). Mean VAS neck pain scores improved significantly (p<0.01) at 12 months. Improvements in mean VAS arm pain scores were also measured; these were 5.3 (right) and 5.1 (left) pre-operatively, and 1.1 (right) and 0.6 (left) at 12 months after surgery.

Disc height at both implanted levels also increased early postoperatively and was maintained to 12-month follow-up, Guyer reported.

Flexion/extension range of motion (ROM) at the inferior level was increased (p<0.05), from 6.1 at the preoperative stage to 7.1 at six weeks, and remained at an improved level through to 12 months (8.7). ROM at the superior level increased, Guyer noted, from 8.4 pre-operatively, measuring 7.6 at six weeks and 9.4 at 12 months.

Guyer said that the early study results suggest that PEEK-on-ceramic TDR devices may be a future consideration for the treatment of symptoms arising from two-level degenerative conditions of the cervical spine, due to the decreases in pain and function scores compared to the pre-operative values, which were maintained through 12-month follow-up.

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March 2020 | Issue 54

Conference coverage

Technology and the changing role of the spinal surgeon

to the patient and figure out exactly what the problem is, what the best treatment is—we need to summarise all of the literature, all of the personal experience we have, to come up with the optimal treatment plan. However, we are going to have devices, tools and robotics that are going to help us with these discussions.

Virtual reality, including 3D imaging, will play an increasing role in planning complex spinal deformity surgery in the near future, according to Lawrence Lenke (Division of Spinal Surgery, New York-Presbyterian Och Spine Hospital, New York, USA). At the 5th Annual International Spinal Deformity Symposium (ISDS 2019; 6–7 December; New York, USA), Lenke demonstrated the use of 360-degree virtual planning for complex spinal deformity correction using software developed by Surgical Theater (Los Angeles, USA). Afterwards, he spoke to Spinal News International about technology, the changing role of the surgeon, and, the increasing prevalence of sub-specialisation within the spinal field.

You have been at the forefront of research on the use of 3D imaging in planning for complex spinal surgery. To what extent do you see this becoming common practice?

One of the main limitations to the evaluation of complex spinal deformity patients is that we have to look at the separate studies; a CT scan to evaluate the bony components of the deformity; an MRI scan to evaluate the neurologic components of the deformity. For many years now, I have been using 3D printed spinal models of complex spinal deformity patients to prepare and perform these spinal reconstructions. Now, using technology that was initially used in complex brain surgery, we can merge the MRI and CT scans together to create a 3D image that has not only the bony elements of a deformity but also the neurologic elements, the vascular elements and other soft tissues. We can thus create a 3D model of all of these elements that we can manipulate in any perspective we want, including not only external visualisation from any angle, but also internal visualisation going down the spinal canal.

From the perspective of planning and understanding the deformity, that is incredibly helpful; even for someone who has been doing deformity surgery for 27 years.

Is there value in employing this technology in simpler surgeries?

Any time you are doing surgery there are adjacent vascular or neurologic structures that have to be understood. In the cervical spine, for example, I think this would be helpful. Even in a “straightforward” cervical spine impingement, I think surgeons will want to know exactly where that spinal cord impingement is, virtually. Also, in the upper cervical spine, knowing precisely where the vertebral arteries are located in relation to the posterior bony elements would be

The more information we have and the more surgeons limit their practice, the more sub-specialisation occurs.

When I started my practice, I was an orthopaedic surgeon specialising in spinal surgery. Now, I do not even consider myself an orthopaedic surgeon, I am currently a spinal surgeon with a spinal deformity sub-specialisation. Thus, within spinal surgery now there are sub-specialisations in spinal deformity surgery, cervical spinal surgery, lumbar degenerative surgery, minimally invasive surgery, just to name a few. Each of those sub-specialisations, I would anticipate, will become a specialisation with its own training programmes and certifications.

beneficial. There is the ability now, not only to visualise various spinal cord and nerve impingements, but there are tools that can take structures away.

Thus, we can do what is called a virtual laminectomy or corpectomy, on a 3D image we can take away the bone to release the spinal cord and we can do that in the planning phase ahead of time.

So from that perspective, even “simple” spinal surgeries could be What have been the takeaway Lawrence Lenke rehearsed, and especially those that are messages and themes from this being done less invasively, where you year’s ISDS meeting? are not seeing the anatomy as well. Seeing this virtually, Our goal of finding the optimal spinal alignment in ahead of time, will help surgeons understand the patients, which has been so elusive, is still problematic. anatomy when there is not as much visualisation during One of the reasons is that, although we have a better the surgery. There is definitely a role for “simple” spinal understanding of what optimal spinal alignment is in surgeries using this technology, which would benefit patients who do not have spinal pathology, things get trainees, as well as practicing spinal surgeons. much more complicated when various spinal pathologies occur.

How do you see technological advances Once we start performing instrumentations and such as robotics, artificial intelligence and fusions and rigidly immobilising various parts of 3D imaging coming together to change the the spine, there is a new normal. Basically everyone role of the spinal surgeon? becomes their own separate database, their own separate A key point is that before someone enters the operating articulated chain of spinal segments. What we can apply room, the physician or surgeon has to decide that the to one patient at a certain age, with a certain fusion level patient requires surgery, and that the type of procedure may not be applicable to another patient who has the to be performed is in their best interests, which we refer same fusion levels, in the same age. It is like your own to as patient-informed decision making and consent. personalised genomic set point of your spinal alignment.

That is the value of still being involved in the We are slowly realising that, and what it means is that discussions with the patients. Having the patients we need big data to help us sort out what type of spinal understand the risk-benefit ratio and having multirealignment we perform on patients. disciplinary clinics that evaluate the risks-benefit ratio We are also going to need this meeting to go on for a of patients considering spinal surgery. Thus, I do not long, long time to help figure out exactly what type of think the physician or surgeon is going away any time surgery we do to best treat patients, to give them the best soon. The surgeon still needs to be in a position to talk outcome.

Opioid use lower in Prestige LP CDA patients The percentage of patients using opioid medication once or more a day after receiving the Prestige LP cervical disc arthroplasty (CDA) (Medtronic) was statistically lower than those using those two drugs after undergoing two-level anterior cervical discectomy and fusion (ACDF), according to 10-year follow-up findings presented at the International Society for the Advancement of Spine Surgery (ISASS) annual meeting (ISASS20; February 26–28, Puerto Rico, USA).

THE FINDINGS WERE presented

by Scott Hodges (Center for Sports Medicine and Orthopaedics, Chattanooga, USA). Hodges explained that previous publications from the US Food and Drug Administration (FDA) Investigational Device Exemption (IDE) randomised study compared two-

When you joined the field, discussion on spine focused on whether spine should become its own distinct section within orthopaedic surgery—has it reached a stage that spinal deformity correction could be considered its own specialty?

level Prestige LP CDA with two-level ACDF and had demonstrated statistical superiority for CDA in overall success, neck disability index (NDI), and neck pain, as well as secondary surgeries at the index and adjacent levels up to 10 years.

The improvements, he said, may lead to less use of pain medications for CDA

patients. He compared opioid medication use between Prestige LP CDA and ACDF patients from that study.

During the initial FDA IDE study, 397 subjects with two-level degenerative disc disease were randomised to receive either CDA (n=209) or ACDF (n=188) treatment. At six weeks, three and six months pre-operatively, and one, two, three, five, seven, and 10 years postoperatively, participants were asked how often during the previous week they had used weak or strong narcotics, respectively, for their neck or arm pain.

Hodges and colleagues found that at the pre-operative Prestige LP implant

stage, the percentages by group—47.8% for CDA and 44.4% for ACDF—were similar (p=0.545). And, while it was found that the percentages decreased substantially for both CDA and ACDF groups after surgery, Hodges and colleagues report that the percentages of CDA patients who used narcotic medications once or more a day were significantly lower.

The study group concluded that the percentage of patients using opioid medications once or more a day after receiving the Prestige LP CDA was statistically lower than those in the ACDF group both overall and at most postoperative time points.

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March 2020 | Issue 54

Biologics

Current evidence and future uses of BMP in spinal surgery Steven Glassman Comment & Analysis Steven Glassman charts the development of bone morphogenetic proteins (BMPs) and their use in spinal procedures, as well as current and future uses.

B

MP was discovered by Marshall Urist, and first reported in Science in 1961. A company named Genetics Institute ultimately isolated the protein, and recombinant BMP was first manufactured in 1989. Over the next 10 years, extensive basic science and animal research was undertaken to determine the appropriate carrier, delivery mechanism, dose and concentration for clinical use in spinal fusion.

The preparatory animal studies were most successful for anterior interbody fusion and a subsequent US Food and Drug Administration (FDA) trial led to the approval of Infuse Bone Graft in combination with LT cages for L5-S1 anterior interbody fusion. Animal models for posterolateral fusion turned out to be more difficult and, in particular, primate studies suggested that posterolateral fusion would require a different carrier and a significantly greater dose and concentration of BMP as compared to anterior interbody fusion.

With the clinical availability of BMP, usage increased rapidly. Not surprisingly, most of the BMP usage was not for anterior interbody fusion, but for the more commonly performed posterior procedures, including posterolateral fusion and TLIF. Within a few years, BMP was used in a very substantial percentage of the lumbar fusion procedures performed across the country.

Despite using the clinically available dose and concentration intended for single level anterior interbody fusion, initial reports indicated acceptable posterior fusion rates, even in multilevel procedures.3 With wider use of BMP, a number of complications were more frequently observed. By and large, these complications reflected the underlying activity of the protein. BMP induces rapid bone turnover, and while this generally results in fusion healing, an initial period of osteolysis was sometimes observed.

This was most frequently problematic with anterior fusion using femoral ring allografts, as the intrinsic stability of the construct was not sufficient to withstand the initial phase of osteolysis. BMP also has chemotactic properties, and thus

complications related to oedema and swelling were noted. The most dramatic example of complications secondary to tissue swelling was in anterior cervical applications, where cases of respiratory distress, re-intubation and even death were reported.4 This resulted in an FDA black box warning against the use of BMP in the cervical spine.

Probably the most common complications were secondary to the intended effect of BMP, that is bone formation. Particularly in TLIF, BMP in and around the foramen or spinal canal occasionally resulted in bony overgrowth and, in some instances, significant neural compression. This appeared to be most common with minimally invasive approaches, where the desire for BMP to avoid bone grafting was greatest, but the very limited space led to concentration of the protein and a higher risk of bony overgrowth. At that time, surgeons seemed to be managing the complication profile effectively, using progressively smaller doses of BMP without obvious deterioration in fusion rate.5 In 2011, after nine years of widespread

June 2011. In peer reviewed articles and editorial comment, this edition of The Spine Journal stated that the complications associated with BMP were orders of magnitude greater then had been previously reported.6 Of particular impact, one article suggested that the use of BMP was associated with the development of cancer.7 These findings were reported widely in the lay press, and BMP use dropped precipitously.

Over subsequent years, extensive resources were dedicated to a reexamination of existing BMP data as well as in-depth study of the known BMP complications.8,9 This work largely confirmed earlier literature, and contradicted the dramatic assertions of an under-reported or inaccurately described complication profile. Large database studies comparing spinal fusion procedures with and without BMP validated the concern for increased complications in the anterior cervical spine, but demonstrated no difference in complication rate for posterior cervical, thoracolumbar, or lumbar applications.10 Further, multiple studies from a variety of large databases, as well as the National Cancer Institute, demonstrated no relationship between BMP and the development of cancer.11,12 Similarly, a large single-center analysis of adult deformity patients treated with very high doses of BMP also found no increase in cancer rates.13 So where are we after what turned out to be largely a false alarm, and then another 10 years of BMP availability?

At present, BMP use has rebounded to approximately 90% of the frequency reported prior to 2011 on a per-case basis, although the dose per case is significantly lower. The most well accepted indications are anterior interbody fusion (the “on-label” indication), adult spinal deformity and pseudarthrosis. For adult spinal deformity, there is some evidence that BMP in modest doses may be cost-effective, based upon the frequency of pseudarthrosis and the high cost of revision in those patients.

At present, BMP use has rebounded to approximately 90% of the frequency reported prior to 2011.” clinical use, BMP was clearly accepted as a treatment option for spinal fusion surgery. Surgeons seemed well aware of the risk profile and, in particular, BMP use in the cervical spine was a controversial topic. There was also an obvious trend toward smaller doses for most applications. The primary concern, however, was cost. There was certainly discussion about the need to better define those procedures for which BMP might be both efficacious and cost-effective, but there was little evidence that surgeons were modulating their BMP usage on that basis.

The landscape around BMP use changed dramatically with the publication of a special edition of The Spine Journal dedicated to BMP in

As has always been the case, BMP is most commonly used for posterior degenerative lumbar indications.

For posterolateral fusion, the risks are low and the literature suggests cost-effectiveness for older patients undergoing multilevel fusion.14 For TLIF, the underlying nonunion rate is lower and the risk for radiculopathy secondary to ectopic bone formation is slightly higher, so demonstrating a cost–benefit advantage will be more difficult. On the flip side, the cost tradeoff may be worthwhile in MIS-TLIF if disc preparation is suboptimal or risk for pseudarthrosis is elevated.

BMP use in the cervical spine is less common. Although the significant complications that led to the FDA black

box warning were essentially all in the anterior cervical spine, the warning covers cervical use in general. This may certainly be a deterrent. Some surgeons are using very small doses of BMP, and also adding a sealant over the disc space for multilevel ACDF. For me, the risk outweighs the benefit. The safety profile for posterior cervical applications appears more benign, and could be weighed against patient specific risk factors and the difficulty of accessing the iliac crest in some instances.

As was the case in 2010, the decisionmaking process around BMP for spinal fusion in 2020 is primarily a cost–benefit analysis. There is mounting experience, and a little bit of evidence, suggesting that smaller doses are effective.15 That would obviously help the cost–benefit equation. Ongoing research into BMP binding proteins and other adjunctive strategies raises the possibility that even smaller doses may be a viable alternative in the future.16 The effectiveness of new alternatives based upon implant materials, surface coatings, or biologic strategies are all under study. It seems a little bit ironic that the question surgeons ask at this point is not “how does the fusion rate compare to iliac crest graft?”, but rather, “how does the fusion rate compare to BMP?” Steven Glassman is the managing director of Orthopaedic Surgery at Norton Healthcare, Louisville, USA, and a former president of the Scoliosis Research Society (SRS).

References 1. Urist MR. Bone: formation by autoinduction. Science.

1965; 150 (3698): 893–9 2. Burkus JK, Transfeldt EE, Kitchel SH, et al. Clinical and radiographic outcomes of anterior lumbar interbody fusion using recombinant human bone morphogenetic protein-2.

Spine 2002; 27(21): 2396–408 3. Glassman SD, Carreon LY, Campbell MJ, et al. The perioperative cost of Infuse bone graft in posterolateral lumbar spine fusion. Spine J. 2008; 8(3): 443–8.

4. Shields LB, Raque GH, Glassman SD, et al. Adverse effects associated with high-dose recombinant human bone morphogenetic protein-2 use in anterior cervical spine fusion. Spine. 2006; 1;31(5): 542–7.

5. Mannion RJ, Nowitzke AM, Wood MJ. Promoting fusion in minimally invasive lumbar interbody stabilization with low-dose bone morphogenic protein-2-but what is the cost? Spine J. 2011; 11(6): 527–33.

6. Carragee EJ, Ghanayem AJ, Weiner BK, et al. A challenge to integrity in spine publications: years of living dangerously with the promotion of bone growth factors.

Spine J. 2011;11(6): 463–8.

7. Carragee EJ, Hurwitz EL, Weiner BK. A critical review of recombinant human bone morphogenetic protein-2 trials in spinal surgery: emerging safety concerns and lessons learned. Spine J. 2011; 11(6): 471–91.

8. Fu R, Selph S, McDonagh M, et al. Effectiveness and harms of recombinant human bone morphogenetic protein-2 in spine fusion: a systematic review and metaanalysis. Ann Intern Med. 2013; 158(12): 890–902.

9. Simmonds MC, Brown JV, Heirs MK, et al. Safety and effectiveness of recombinant human bone morphogenetic protein-2 for spinal fusion: a meta-analysis of individualparticipant data. Ann Intern Med. 2013; 158(12): 877–89.

10. Cahill KS, McCormick PC, Levi AD. A comprehensive assessment of the risk of bone morphogenetic protein use in spinal fusion surgery and postoperative cancer diagnosis. J Neurosurg Spine. 2015; 23(1): 86–93.

11. Beachler DC, Yanik EL, Martin BI, et al. Bone morphogenetic protein use and cancer risk among patients undergoing lumbar arthrodesis: A case-cohort study using the SEER-Medicare database. J Bone Joint Surg Am. 2016; 98(13): 1064–72.

12. Kelly MP, Savage JW, Bentzen SM, et al. Cancer risk from bone morphogenetic protein exposure in spinal arthrodesis. J Bone Joint Surg Am. 2014; 96(17): 1417–22.

Mesfin A, Buchowski JM, Zebala LP, et al. High-dose rhBMP-2 for adults: major and minor complications: a study of 502 spine cases. J Bone Joint Surg Am. 2013; 95(17): 1546–53.

13. Glassman SD, Howard J, Dimar J, et al. Complications with recombinant human bone morphogenic protein-2 in posterolateral spine fusion:a consecutive series of 1,037 cases. Spine. 2011; 36(22): 1849–54.

14. Lytle EJ, Slavnic D, Tong D, et al. Minimally effective dose of bone morphogenetic protein in minimally invasive lumbar interbody fusions: Six hundred ninety patients in a dose-finding longitudinal cohort study. Spine. 2019; 44(14): 989–995.

15. Refaat M, Klineberg EO, Fong MC, et al. Binding to COMP reduces the BMP2 dose for spinal fusion in a rat model. Spine. 2016; 41(14): E829–36.

Issue 54 | March 2020

ABM/P-15 shows superior fusion rates after posterolateral fusion Patients undergoing noninstrumented posterolateral fusion augmented with 15 amino acid residue (ABM/P-15) achieved a 50% fusion rate compared to 20% in those receiving allograft, two-year follow-up results of a European randomised double blind clinical trial have shown. However, the results, published in The Spine Journal, did not translate to better clinical outcomes between the two groups, with longer-term follow-up results expected to provide a more detailed picture of patient outcomes.

T

he research was led by Michael Kjær Jacobsen (Sector for Spine Surgery and Research, Middelfart Hospital, Denmark) and colleagues Mikkel Ø Andersen, Andreas Killerich Andresen, Annette Bennedsgaard

Biologics Jespersen, Christian Støttrup, Leah Y Carreon and Søren Overgård.

The study team write that due to poor bone stock in the elderly, a noninstrumented fusion is commonly performed in Scandinavia when instability is present. Allograft bone is often used as graft extender, with consequent low fusion rates.

The use of ABM/P-15 has shown superior fusion rates in dental and cervical spinal surgery, they add, but no clinical studies have previously been conducted in non-instrumented lumbar fusion surgery.

Through the double-blind randomised clinical trial the study team sought to evaluate patient reported outcomes (PROs) and the intertransverse fusion rate in non-instrumented posterolateral fusion with either ABM/P-15 (i-FACTOR, Cerapedics) or allograft. Patients aged ≥60 years with degenerative spondylolisthesis (DS) undergoing decompression and non-instrumented posterolateral fusion were chosen for inclusion in the trial with the assessed outcomes including visual analogue scales (VAS) for back (BP) and leg pain (LP), Oswestry Disability Index and EuroQoL-5D. One hundred and one patients were enrolled in the study and randomised 1:1 to either ABM/P-15 (mixed 50/50, 5cc/level) or allograft bone (30g/level), both mixed with local bone graft. PROs were collected at baseline and at 12 and 24 months after surgery. The patients underwent one-year postoperative

fine cut CT-scans (0.9 mm) with reconstructions, independently evaluated by three reviewers. Fusion status was concluded by consensus of two of the three as “fusion” or “no fusion.”

A total of 49 patients were available for analysis in both cohorts, and the two groups were similar in terms of sex distribution, age and number of levels fused. The study team found that the fusion rate was significantly higher in the ABM/P-15 group, with 50% fused compared with 20% in the allograft group. PROs at baseline and at all followup timepoints were similar between the two groups, the researchers note.

The researchers conclude that patients undergoing non-instrumented posterolateral fusion augmented

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of allograft, and we needed some sort of substitute. We picked i-Factor because we thought that might be a good alternative.

I would have been happy if we had just obtained the same fusion rates as allograft, so I was surprised that they actually almost doubled the fusion rates.”

He added: “I think it is interesting that we almost doubled the fusion rate, because it is a major problem in elderly persons with poor bone stock. Hopefully down the road it will reflect in better clinical results too, instead of just the better fusion rates.”

Commenting on the ongoing assessment of the long-term followup data, Andersen noted that work is being done to reassess patients from the original trial. He said: “Patients were

It is interesting that we almost doubled the fusion rate, because it is a major problem in elderly people.” with ABM/P-15 had a statistically significantly higher fusion rate compared to allograft when evaluated with postoperative fine cut CT-scans (0.9 mm) with reconstructions.

Speaking to Spinal News International, Andersen said that the study team had been surprised by the improvement in fusion rates seen in patients in the i-FACTOR group compared to allograft.

He said: “The reason why we went into the study was because we were short

operated in 2012 and 2013, and we are now out at five years. We are bringing all of the patients back in for a follow-up study to look into re-operation rates and patient reported outcomes with more than five years follow-up.

“Of the 90 patients alive, I have had about 60 patients in the outpatient clinic and got new CT scans on them.

Slowly we will get through the lot but I think it will be done within the next three months.”

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March 2020 | Issue 54

Interview

Profile

Alex Vaccaro

Alex Vaccaro is the immediate past president of the Cervical Spine Research Society (CSRS) and a member representative for AO Spine. He talks to Spinal News International about his career in spine care, how the field has changed since he began practicing, the increasing importance of cost considerations in the treatment of spinal conditions, and his work as a spine consultant for the Philadelphia Eagles.

Why did you decide to become a doctor and why, in particular, did you decide to specialise in the spine?

I decided to become a doctor when I was eight years old when I developed a close relationship with my family physician, Frank Ferraro, a man of great integrity, wisdom and knowledge. I decided to specialise in spine when I worked with one of my mentors, Jerome Cotler, whom I consider one of the finest and most compassionate spinal physicians I have ever met.

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

I have had several important mentors in my career. Dick Rothman taught me how to think in a logical manner and to provide evidence-based care in a methodical manner to improve the quality of life of those suffering from orthopaedic ailments. Steve Garfin taught me how to manage an extremely busy academic career and how to do complex spinal surgery, and Jerome Cotler taught me the principles of extreme hard work, sacrifice and commitment to excellence in orthopaedics.

How has the field changed since you started your career, and what do you feel has been the most important development?

The most important change that I have noted over my career is the explosion of technology, which has made our ability to provide better care to patients with all sorts of orthopaedic ailments. In spinal surgery, this involved the creation of segmental spinal instrumentation, biologics to improve bony healing, computer-imaged technology to navigate the spine, registries, big data and the appreciation of age-related changes in spinal posture.

Later in my career, I have developed an appreciation of the importance of understanding the business of medicine to improve efficiency and decrease the cost of care, minimise redundancy, and wasted variation in treatment.

What do you think are the main challenges facing spine care at the moment? What are the potential solutions?

The main challenge facing spine care at the present time is cost. We have several unanswered challenges that will cost society a lot of money to better understand.

This includes the optimal management of spinal deformity in ageing, a cure for spinal cord injury and the optimal management of symptomatic degenerative disc disease. Each one of these challenges costs a significant amount of money. Faced with the growing expense of healthcare, which at present uses approximately 19% of gross domestic product (GDP), this will be very challenging unless we shift the cost curve for medical care for our ageing population in the near future.

What are your current research interests, and what are your future priorities for research?

My current research interests lie in trying to discover

the cure for spinal cord injury and the use of advanced technologies to make spinal deformity surgery safer, more efficient and less costly. My institution will continue to look for biological solutions for disc regenerative and novel ways to manage spinal trauma and spinal cord injury.

What is the most interesting piece of research you have read recently?

The most interesting piece of research I have read recently was the use of functional magnetic resonance imaging (MRI) following repetitive head trauma in collision athletes in order to assess for subclinical traumatic brain injury. This has great importance for me as I am the team spine physician of the Philadelphia Eagles football team, and it is obligatory for us to find ways to minimise the long-term effects that repetitive head trauma may pose to young athletes participating in collision sports.

In your opinion, what are the most exciting new developments in spine care that we can expect in the next five to 10 years?

I think the most important development that we can expect in spinal care is the improvement of minimally invasive strategies of accessing the spine through robotic technology, allowing the surgeon to navigate critical neural and vascular structures with the aid of neurophysiological tools to more safely manage complex spinal deformities and minimise the risk of neurologic injury.

The most important development we can expect is the improvement of minimally invasive strategies.â&#x20AC;?

You have been an active member of a number of leading spine organisations; how has this helped to shape your career?

I have been involved in many important organisations. I have developed a great appreciation for the importance of leadership and mentorship training through the American Academy of Orthopaedic Surgery and its mission to train young orthopaedic leaders. I am the past president of the American Spinal Injury Association, and I was recently the president of the Cervical Spine Research Society. I greatly enjoy my attendance at the Scoliosis Research Society, and I have found these meetings to be a wonderful venue to connect and network with academic spine surgeons, and to come up with innovative research programmes that are mutually beneficial to all spinal care providers.

You recently served as the president of the CSRS, what do you feel you were able to accomplish in the role?

Our number one goal was to kick-start a cervical spine registry. The importance of collecting data in a registry format will allow study of treatment trends and complications of cervical spinal care. There is interest in combining the efforts of the orthopaedic and neurologic communities to develop a comprehensive spine registry allowing the CSRS to lead the development of the cervical module. Another major achievement was the seamless transition of changing the management company to Executive Director Incorporated (EDI) which was a monumental task and one that went seamlessly.

You have been elected to serve as member representative for AO Spine in 2020. What are your priorities for the position?

As a member representative of AO Spine, I will have the opportunity to contribute to the worldwide strategy of spine surgeon education, training and research.

Issue 54 | March 2020

Interview

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Fact File

Qualifications

2015 MBA, Temple Fox School of Business 2007 PhD, University of Utrecht, The Netherlands 1993 Spine Fellowship, University of California, San Diego, USA 1992 Resident, Orthopaedic Surgery, Thomas Jefferson University Hospital Affiliated Programs, Philadelphia, USA 1988 Surgical Internship, Cedars-Sinai Medical Center, Los Angeles, USA

Professional positions (Selected)

Chairman of Orthopaedics, Sidney Kimmel Medical College, Thomas Jefferson University Elected president, Rothman Institute Professor of Orthopaedics and Neurosurgery, Thomas Jefferson University Hospital

Memberships (Selected)

Cervical Spine Research Society (Immediate past president) North American Spine Society Scoliosis Research Society American Academy of Orthopaedic Surgery American Orthopaedic Association International Society For The Study Of The Lumbar Spine International Society for the Advancement of Spine Surgery (ISASS)

Publications

In addition to networking, the international board will prioritise research money allocation, topic and location selection for the yearly meeting, and continued educational course development throughout the world.

What is your proudest career achievement to date, and why?

My proudest achievement along with my wife Lauren, is the upbringing of our children Max, Alex, Julianna, Christian, and Mia. Watching them develop with kindness, compassion and curiosity with an interest in sports, academics, and humanity has been our most cherished achievement.

What advice would you give to someone hoping to start a career in spinal surgery?

If someone wanted to start a career in spinal surgery, I would ask them to figure out what area of spinal care has been least explored and developed. I would spend time

developing research protocols and enlisting stakeholders from all areas of science to explore solutions to these unanswered questions. This would include robotic surgery, spinal cord regeneration, and the use of stem cells in intervertebral disk degeneration.

What would you have been if you had not been a medical doctor?

If I had not been a medical doctor, I probably would have become an artist. I used to spend a great deal of time drawing and painting. Now, as a surgeon and father I no longer have the time to enjoy something that was very important to me when I was younger.

Outside of medicine, what are your hobbies and interests?

Outside of medicine I have several hobbies; collecting mint US stamps; travelling; participating in sports and most importantly, raising my children and participating in their activities.

Vaccaro AR, Baron EM, Sanfilippo J, et al: Reliability of a novel classification system for thoracolumbar injuries: The thoracolumbar injury severity score. Spine; 2006; 31(11): S62–69.

Vaccaro AR, Hulbert RJ, Patel AA, et al: Spine Trauma Study Group: The subaxial cervical spine injury classification system: A novel approach to recognize the importance of morphology, neurology, and integrity of the disco-ligamentous complex. Spine; 2007; 23: 65–74.

Vaccaro AR, Lim M, Hulbert RJ, et al: Surgical decision making for unstable thoracolumbar spine injuries. J Spinal Disord Tech; 2006; 19: 1–11.

Vaccaro AR, Sahni D, Pahl MA, et al: Longterm magnetic resonance imaging evaluation of bioresorbable anterior cervical plate resorption following fusion for degenerative disk disruption.

Spine; 2006; 18: 2091–2094.

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March 2020 | Issue 54

Technology

Vision 2020

How will technology shape spinal surgery during the next decade?

The last decade proved to be a turning point in the use of advanced technologies in spinal surgery, with developments in areas such as robotics for screw placement, computerassisted navigation and new techniques for minimally invasive surgery all moving forward at pace. Many believe that further technological development across areas such as augmented and virtual reality, endoscopic surgery and 3D printed implants will continue to change approaches to spinal surgery throughout the course of the next 10 years. Spinal News International spoke to four surgeons who have led research into new technologies to ask their view on the developments that will shape the field of spinal surgery over the coming decade.

surgery (MIS), says that endoscopic spinal surgery, although not new in concept, has only recently become more common practice among surgeons in Europe and the USA. “It looks like MIS surgery is moving quickly into endoscopy and this, in the very near future, will be one of the standard approaches for the spine across the world. Reasons for that are mainly the increasing interest from patients, doctors and companies in minimising the impact of the surgical approach, the great improvements in visualisation, optics and image resolution, and the development of curriculum and teaching activities for endoscopy.”

Expandable technologies, in particular interbody cages, are another area where Parajon believes advances are being made. “They have been in the market for a long time,” he says, “but in recent years the improvement in their design and biomechanical properties, and the increasing interest in minimising complications and improving sagittal balance outcomes, has made them more interesting. In my opinion, the use of expandable interbody cages will be a very common practice in the next few years.”

3D navigation

Parajon comments that 3D nagivation has become the “standard of care” in many major healthcare centres, because of its capacity to increase accuracy of implant placements, decreased exposure to radiation, as well as advantages including better tumour resection and implant selection. “Robots seem to be the next step in this evolution,” he adds. “They can improve accuracy even more and give the opportunity to explore easier positioning of patients—for example, placing screws in LLIF surgeries in a lateral position. Robotics combine ‘normal’ 3D navigation with robotic placement of screws.” Parajon believes that the potential to integrate augmented reality systems into spinal procedures will “definitely be the next step in our spine ORs”.

Finally, and “by no means least”, says Parajon, the use of big data analytics is likely to have a profound impact on spinal surgery in the 2020s. “This will take a little more time to be relevant in our daily clinical practice, but probably will have more impact.

“Nowadays, surgeons are able to put screws and other implants with very high accuracy and morbidity in big spine surgeries has decreased significantly with the aid of less invasive approaches. But, our biggest challenge is still knowing the best indication for each pathology and each single patient case. Being able to

A robot-assisted spine procedure

“I

f you look historically, 10 years ago there was this underlying sense within the spine community that was very depressed,” says Isador Lieberman (Texas Back Institute; Plano, USA), who has been a pioneer in robotic-assisted spinal surgery, having helped to develop SpineAssist (Mazor) the first robotic guidance system to have been employed in spinal surgery. “We had been using pedicle screws for a long time and the biggest technological advance that we saw was the different pitch thread on the pedicle screw, or a different tool configuration. We just didn’t have the excitement. Over the last five years, with the advance and the acceptance of navigation and robotics, all of a sudden, this excitement came back into the spine community.”

Lieberman comments that the spinal surgery field is currently at an “inflection point” regarding the use of automation within the operating theatre. “That is going to continue to grow and continue to be a very important component of what we do surgically,” he says, looking to the near future. He sees augmented reality as the next area for major development. “That is coming and is going to be a huge advantage—a real change in what we are doing,” he told Spinal News International. “When we marry the augmented reality to the navigation and robotics: I can plan an operation,

I can execute the operation, I can validate the operation, all before the patient even gets to the operating room.”

Elsewhere, Lieberman says advances in implants and tool design, bone cutting equipment and soft tissue removal will also lead to improvements in patient outcomes. “There are a lot of implants and new tools that are coming out. We are getting much better with bone cutting and soft tissue removal tools, whether it is high energy lasers or ultrasound, or ultrasonic devices.

When you couple that with augmented reality, with guidance and robotics, it just makes more sense. I can remove bone more precisely, less tissue damage, and it protects the collateral tissue, the nerves and blood vessels. All of those things are really, really important,“ he says.

Minimally invasive surgery

“If I had to say what major technological developments will have the biggest impact on spinal surgery throughout the 2020s,” Avelino Parajon, head of section of neurosurgery at Hospital Universitario Ramón y Cajal (Madrid, Spain) comments, “In order of significance, I believe it will be: endoscopy; expandable technology (interbody cages); robotics and augmented reality; and big data.”

Parajon, who specialises in minimally invasive

The use of expandable interbody cages will be a very common practice in the next few years.” study big collections of data outcomes from different groups of patients with their own characteristics treated by different approaches will probably give us the solution to some of these relevant questions.”

Enrico Tessitore, deputy chairman of the Neurosurgical Unit at Geneva University Hospitals (Geneva, Switzerland), and president elect of the Swiss Spine Society told Spinal News International that the continued development of robotics within the spinal field will be a hallmark of the 2020s. Further evidence of their efficacy will be crucial in advancing this push, Tessitore said. Consequently Geneva University Hospitals is one of a number of European centres to participate in the European Robotic Spinal Instrumentation (EUROSPIN) study, involving patients receiving thoracolumbar pedicle screw placement

Issue 54 | March 2020

for degenerative disease, infections or tumours. The three arms of study will consist of robot-guided (RG), navigated (NV), or freehand (FH) screw insertion to assess the performance of each. “The primary outcome is not the accuracy of the screws but the number of screws that are revised. This may have a clinical impact on patient outcome,” Tessitore said. “We have already started to recruit subjects, and we are pretty convinced that we will find no revised screws in the navigation

I think we are not far from having robots that will be able to drill or remove bone in the way the surgeon has planned.” and robotics cohorts.”

Furthermore, Tessitore comments that he sees the range of surgical applications for which robotic technologies can be employed moving beyond screw placement and into more complex procedures during the course of the next decade.

He says: “I am convinced that screw insertion was the first and most common procedure addressed by companies developing Isador Lieberman robotics, but they have now succeeded. Having the radiation exposure and the screw misplacement drop down to zero, this is a clear success of the technology. Nevertheless, I am not convinced that good technology should be limited to the screw insertion. Putting a screw in the lumbar pedicle, which is 10mm width is not a big problem—you probably don’t need a €1 million device to put such a screw in.

“I would expect further developments in terms of some other steps of the spinal procedures. For example, decompression. We are not that far from having robots that will be able to drill or remove bone in the way the surgeon has planned.”

Technology

and director of the Neurosurgical Spine Center of Johns Hopkins Medicine (Baltimore, USA), “the intersection of engineering and spinal surgery” is the trend he expects to see in the coming decade. Theodore is himself a pioneer in robotics in spinal surgery, having invented the Excelsius (Globus Medical) spinal surgery robot.

“Spinal surgery meets engineering”

He sees the further integration of image guidance technology, alongside robotics as having a major impact in future. “When we look at the data, it is quite clear. If you utilise screws in just freehand, your accuracy rate is about 70%. That increases to the low nineties when you start using X-ray, and the high nineties when you start utilising image guidance. We have this data, so why aren’t people using it? The majority of screws that are not perfectly placed are usually harmless. If it doesn’t cause harm to the patient, then we are not jumping up and down about that. Then you add robotics in and

Avelino Parajon

Enrico Tessitore

that has changed everything now,” he comments. “The whole concept of utilising robotics with image guidance is that we can reliably and quickly get to a point where the robot can take us to any trajectory that would be impossible with X-ray in a very rapid and very precise fashion.”

Despite being a pioneer in the field, Theodore does not see robots replacing the role of the surgeon entirely, although he does concur that increasing applications of the technology will create a further demand for robotics in the OR. “The robot is not going to replace the surgeon,” he says. “It is also not going to take a

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put the drill in, or the bone scalpel and you remove the bone yourself to do that. But in the fraction of the time that we are taking to do it freehand, for instance.”

Patient safety and improving outcomes from robotic-assisted surgery

Although cost is recognised as a barrier to wider adoption of robotics in spinal surgery, Theodore argues that this should be offset by potential benefits in patient safety and outcomes. “First and foremost,” he says, “it is about patient safety. Can we improve our outcomes through the use of this technology? By avoiding one misplaced screw into the spinal canal that causes a neurologic injury, the robot has paid for itself. And, you also have the ability to place hardware more accurately.

If you revise something intraoperatively you have already made the mistake. Prevention is better.”

Beyond robotics, 3D printing is another area that Theodore sees advancing in the spinal surgery arena.

“3D printed implants,” he says, “I think, are very exciting. I don’t know if it is going to change the world, but it is another example of engineering and surgery where we are able to make a device with this 3D printed surface that allows bony ingrowth so that the fusion is easier than having to pack in bone, or to use chemicals like bone morphogenic protein, where you probably eliminate the Nicholas Theodore usage of that through various technologies.”

Theodore also believes that employing data analytics in the spine theatre will create further benefits. He details a project being undertaken at Johns Hopkins, titled Spine Cloud, that is working towards this aim.

“This involves utilising imaging, patients images throughout the course of their disease process, before and after surgery. We will be utlising data from the electronic medical record and then also patient reported outcomes, to predict who is going to do well and what surgeries work and what surgeries don’t.” The outcome from this, Theodore says, will be the ability to specify a set of patient parameters at the beginning of a treatment

3D printing

With regards to spinal implants, Tessitore describes the continued development of 3D printing as showing “great promise” particularly in promoting bone fusion. “Titanium 3D printed cages provide a peculiar geometry which optimises bone ingrowth profile, but this needs to be confirmed by further studies.” He adds that his institution is taking part in a randomised study involving 3D printed interbody cages from the Swiss manufacturer Spineart. “We perform a very early SPECT-CT scan in order to see if there is an early integration of these cages. Compared to PEEK cages, for example. 3D printing technology seems to promote fusion by facilitating ingrowth of bony cells from the endplates into the cage.”

Tessitore also pointed to developments in endoscopic surgery as another area for growth. He said: “There have been big developments in terms of endoscopic devices. Joimax and Richard Wolfe (RIWO) are investing a lot in new endoscopes. I have been really impressed with the improvements in optics and image resolution, amelioration of working channels, and creation of dedicated instruments, like rongeurs and drills, which was not the case with the earlier generation of endoscopes.”

For Nicholas Theodore, professor of neurosurgery at the Johns Hopkins University School of Medicine,

DePuy Synthes’ Conduit Interbody Platform, launched in 2019, features 3D printed titanium interbody implants for spinal fusion surgery

bad surgeon and make them good. But, it certainly could take a good surgeon or an adequate surgeon and make them much better.” On future applications for the technology, he adds: “When we start introducing drills to be able to cut bone and jig bone, that will be the next step. I will go out on a limb and say that will also be able to be planned. In other words, the robot can pick the best site to do the osteotomy, for instance for scoliosis cases. It will take you to that position, you

process, which are input into a software programme.

These parameters can then be measured against data from outcomes of previous surgeries, allowing the software programme to predict how a patient will respond to a particular procedure. Theodore concludes: “This whole ability to predict how we are going to do it all, and also inform us of what might be the best procedure for any given patient is. To me that is mindblowing.”

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March 2020 | Issue 54

Prophylaxis

Researchers push ‘defined’ role for DVT after spinal surgery A review of bleeding and thrombotic complication rates in elective spine surgery patients has suggested that further study is needed to determine optimal thromboprophylaxis strategies for the prevention of complications such as deep vein thrombosis (DVT).

This is the conclusion of Sean Pirkle (Department of Orthopaedic Surgery and Rehabilitation Medicine, University of Chicago Medical Center, Chicago, USA) and colleagues, who carried out the research, published in the Global Spine Journal.

P

irkle and colleagues sought to examine the utilisation rate of postoperative DVT prophylaxis, and compare the incidence and severity of bleeding and thrombotic complications in elective spine surgery patients.

Many surgeons, they note, rely on a patient’s risk profile to advise the administration of chemical prophylaxis postoperatively to limit the risk of venous thromboembolism. The study team found that historically, the incidence of postoperative epidural haematoma has been reported in 0.3% of cases, compared with values ranging from 0.8–15.5% for DVT following elective spinal surgery.

Currently, Pirkle and colleagues report, there are no universally agreed recommendations for anticoagulant administration in spinal surgery patients, although some small studies

have investigated outcomes related to anticoagulant prophylaxis following spinal surgery, documenting a low risk of bleeding complications, including epidural haematomas.

Because of the low incidence of severe bleeding and thrombotic complications, the researchers write, a large data sample is required to assess if one type of complication occurs more frequently than another.

Pirkle and colleagues conducted a retrospective review of the Humana Insurance subset of the Pearl Diver national database—which contains around 25 million patient records.

The patient population was identified for six different spinal procedures, including: anterior cervical fusion, anterior lumbar fusion, posterior cervical fusion, posterior cervical laminectomy/

laminoplasty, posterior lumbar fusion and posterior lumbar laminectomy.

Patients matching the inclusion criteria were required to have active records in the database for at least six months following the procedure.

Two groups of patients were analysed, composed of those who had not received chemoprophylaxis and those who had received chemoprophylaxis within five days of procedure. Complications were limited in these patients from the same day of intervention until three months post-operation. Researchers compared rates of bleeding complication to thrombotic complications in the two patient groups.

Variables assessed by the researchers included patient age and gender, atrial fibrillation, cancer, chronic obstructive pulmonary disease, congestive heart failure, hypertension, number of levels treated, obesity, oral contraceptive use, prior history of bleeds, prior history of thrombosis and tobacco use.

The study team identified a total of 119,888 patients who fulfilled the inclusion criteria. The majority of these patients (118,720) were not administered DVT chemoprophylaxis within the first five days of their procedure. In this group, overall rates of bleeding and thrombotic complications differed significantly (1.96% vs. 2.45%; p<0.001).

Additionally, Pirkle and colleagues note, the rate of patients who underwent surgical intervention for a wound washout procedure was 0.62% compared to 1.05% for a diagnosis of pulmonary

embolism (p<0.001). This trend was consistent and observed for subanalyses of all six spinal procedures..

In contrast, 1,168 patients were placed on anticoagulant therapy following surgical spine procedures, representing 0.97% of all patients who had undergone spinal procedures in the study. Patients in this group experienced much higher rates of overall thrombotic complications compared to bleeding (10.36% vs. 2.65% p<0.001). However, due to the small sample size represented by this group, no further analysis was conducted.

Discussing the findings, Pirkle and colleagues write that unlike other types of surgical procedure, there is no standard of care in regard to DVT chemical prophylaxis after routine elective spinal surgery. “Studies have suggested caution with the use of chemoprophylaxis while also acknowledging the dearth of quality literature studying this subject,” the study team notes. “As a result, the current practice of chemoprophylaxis after spine surgery is largely driven by dogma and not by quality data.”

They conclude: “In the present study’s population, which did not receive DVT chemoprophylaxis, the risks of thrombotic complications were significantly greater than bleeding complications for patients specifically with atrial fibrillation, cancer, or a prior history of thrombotic complications.”

However, the study team warns that for those not matching these criteria, the risks of DVT prophylaxis may not outweigh the benefits.

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March 2020 | Issue 54

Market watch

Product News US FDA approval for Medicrea’s patient-matched interbody cages

Medicrea has received US Food and Drug Administration (FDA) clearance for UNiD IB3D patient-matched interbody cages, which completes its UNiD ASI (adaptive spine intelligence) platform technology.

UNiD IB3D patient-matched interbody cages are 3D-printed titanium implants which allow customisation of the cage dimensions, features, and endplate morphology. According to Medicrea, it is the first time that this level of customisation is commercially available on the spinal device market.

The cages are specifically designed to precisely match the optimal patient’s surgical and anatomical requirements, determined by the UNiD LAB engineers during the pre-operative planning phase, Medicrea said in a press release.

Through 3D reconstruction of the spine, the engineers map out the exact anatomy of each vertebrae endplate.

They then design the ideal cage to restore proper height and angulation but also to offer an optimised surface contact between the implant and the vertebrae endplates in order to improve stability of the instrumented segment and reduce subsidence.

Denys Sournac, CEO and founder of Medicrea, said: “Until now, the only FDA-cleared patient-matched implants were limited to cranioplasty implants. These are mainly aesthetic and do not bear any weight. UNiD IB3D patient-matched interbody cages are the first patient-matched implants FDAcleared for load bearing applications, specifically designed for spine surgery.”

to simultaneously look at the patient data and see the navigation data without averting their eyes to a remote screen during the procedure. In a press release, Augmedics said that the system is designed to revolutionise how surgery is done by giving the surgeon better control and visualisation.

Augmedics completed a percutaneous laboratory study with the xvision Spine at Rush University Medical Center (Chicago, USA) with investigators Frank Phillips, Camilo Molina, Kornelis Poelstra, Larry Khoo, and Matthew Colman. Ninety-three screws were positioned in the thoracic and sacrolumbar areas of five cadavers. The study was conducted as evidence to the FDA to evaluate the accuracy of the xvision Spine system by comparing the actual screw tip position and trajectory compared to the virtual. The result of overall clinical accuracy, analysed by two independent neuro-radiologists, was 98.9% using the Heary (thoracic) and Gertzbein (lumbar) scales.

“The ability that Augmedics’ xvision provides to visualise the patient’s spinal anatomy in 3D, coupled with live CT images as a retina display, is game changing,” said Frank Phillips (Rush USA). “The efficiency and accuracy this augmented reality technology enables in placing spinal implants without looking away from the surgical field—as well as the ability to “see the spine” through the skin in minimally invasive procedures—differentiates the xvision from conventional spinal navigation platforms. The economics of the xvision system are also compelling in both the hospital and the surgicentre environment.”

First North American installation of EOSedge imaging system

Augmedics’ headset

FDA approves xvision augmented reality spine surgery system

Augmedics has announced that it has received US Food and Drug Administration (FDA) 510(k) clearance for its xvision Spine system (XVS), an augmented reality (AR) guidance system to be used in spine surgery.

The xvision consists of a transparent near-eye display headset and all elements of a traditional navigation system. It determines the position of surgical tools, in real time, and a virtual trajectory is superimposed on the patient’s CT data. The 3D navigation data is then projected onto the surgeon’s retina using the headset, allowing them

EOS imaging has announced the first installation of its new EOSedge system in North America, at CHU SainteJustine Mother and Child University Hospital Centre in Montreal, Canada.

This second EOSedge system installation worldwide follows the first system installation in 2019 at Ste Justine Hospital’s in Lyon, France.

A clinical research programme with EOSedge led by Professor Carl-Éric Aubin and Stefan Parent at CHU SainteJustine will cover areas such as multispectral imaging and biomechanical modelling in multiple clinical applications, as well as clinical studies on adolescent idiopathic scoliosis and bone metabolic conditions.

Mike Lobinsky, chief executive officer of EOS imaging, commented: “We are pleased that the first North American installation of our newly FDA and Health Canada cleared EOSedge system is at an institution with a dedicated value of advancing patient care.

EOS edge system

“This installation marks another step in deploying, on a global scale a solution that not only further improves our dose reduction and whole-body imaging capabilities, but also adds new and unrivalled performance in image resolution and quality. We look forward to quick adoption of this outstanding imaging solution.”

Life Spine receives 510(k) clearance for Steerable Plateau Ti system

Life Spine has received 510(k) clearance from the US Food and Drug Administration (FDA) to market the Steerable Plateau Ti spacer system.

The Steerable Plateau Ti system is available in lengths of 28mm and 32mm and heights ranging from 9–14mm in 1mm increments. The system features Life Spine’s proprietary Osseo-Loc surface architecture of 400–600 micron porosity. The Steerable Plateau Ti system is complemented by Life Spine’s Centric-T pedicle-based retractor system and the Avatar minimally invasive surgery (MIS) spinal fixation system, the company said in a press release.

“The Steerable Plateau Ti system is one of many novel systems slated to join our Micro Invasive portfolio this year,” said Michael Butler, president and CEO of Life Spine. “These launches are testimony to our continued dedication to supporting less invasive procedures. The Steerable Plateau Ti system allows for controlled delivery upon insertion to facilitate positioning in the anterior portion of the disc space and features a curved design to match patient anatomy and maximise endplate coverage.

Additionally, the spacer was designed to restore patient sagittal balance with lordotic options of seven degrees and 12 degrees.”

system uses visible light, eliminating the patient and staff exposure to intraoperative radiation which is common with older technologies. This results in a nearly instantaneous patient registration in almost any surgical position, 7D Surgical said in a press release.

“We have completed more than 1,500 clinical cases with the 7D Surgical system and the feedback from our surgeon users has been tremendous. I am excited to offer these new technologies to our customer base which expand the functionality of the MvIGS system while maintaining our clear advantages in speed and reduced radiation exposure to operating room staff and patients,” said Brian Stuart, vice president of sales and marketing at 7D Surgical.

Cerapedics announces FDA approval of PMA supplement based on two-year clinical data

Cerapedics has announced that the US Food and Drug Administration (FDA) has approved the company’s premarket approval (PMA) supplement for i-FACTOR peptide enhanced bone graft in anterior cervical discectomy and fusion (ACDF) procedures in patients with degenerative cervical disc disease.

Cerapedics requested approval for an updated package insert that incorporates the 24-month follow-up data from subjects enrolled in the original clinical study.

“We are pleased to receive FDA approval of our PMA supplement, which allows i-FACTOR labelling to reflect longer-term clinical data showing that the statistical superiority to autologous bone in overall clinical success that was observed at one year has been maintained at two-year follow up,” said 7D Surgical Jeffrey Marx, president The 7D Surgical system announces and chief operating officer commercial release of its of Cerapedics.

Universal Tracking Kit Cerapedics commercialised 7D Surgical has announced the i-FACTOR bone graft beginning in commercial release of its Universal 2016. The drug-device combination is Tracking Kit, which spine surgeons can based on synthetic small peptide (P-15) use to track and visualise rigid surgical technology that accelerates new bone intrumentation on the MvIGS system. formation in patients with degenerative The 7D Surgical MvIGS system disc disease. The i-FACTOR bone graft utilises camera technology and machine is in a new category of technology vision algorithms to eliminate longand is one of only two drug-device standing frustrations with legacy combination products approved by surgical navigational platforms. The the FDA.