Three Brachial Plexus Injury Subjects' Function After One(+) Year of Upper-Extremity Myoelectric Orthosis Treatment

Research & Presentations

Three Brachial Plexus Injury Subjects’ Function After One(+) Year of Upper-Extremity Myoelectric Orthosis Treatment

By David R. Coleman, CPO, FAAOP

Introduction Traumatic brachial plexus injury (TBPI) is a rare dysfunction causing myriad impairments to the ipsilateral upper extremity (UE) of an individual. 1 Impairments result from a distractive force at the shoulder complex deranging the nerves and disrupting their ability to communicate afferent and efferent signals. Young males are at the highest risk for TBPI because of their incidence of motor-vehicle accident (MVA) or other high-impact traumas, though anyone is vulnerable. 2 Disruptions can present as preganglionic avulsion, rupture, neuroma, or neurapraxia 1-5 (Figure 1). Treatments vary depending on intact innervations, but the most severe dysfunction and most invasive interventions occur with avulsions. 4-6 Elbow flexion is impaired in 95 percent of cases of TBPI due to C5-C6 avulsion or rupture. 4

Our ultimate goal as a health-care team is to have our clients achieve normal (M5) or like-normal (M4) elbow flexion on the manual muscle testing (MMT) scale. Many surgical interventions are available, including muscle graft, muscle transfer, nerve graft, and nerve transfer. Which intervention is used is determined from available muscles and nerves, and a degree of compromise regarding impairment in

Figure 1 Traumatic brachial plexus injury

the donor site. 1,3-6 Because of the extent of damage from MVAs, the chance of restoring function may mean pursuing interventions with low success rates. Motor and sensory deficits in the donor sites must be weighed against the prospective increase in value for the client.

There are many validated nerve and muscle transfers, but a couple are typically utilized as a last resort. One treatment is the intercostal nerve (ICN) transfer to the musculocutaneous nerve (MCN) because of the presence of both motor and sensory neurons, and because the number of axons is similar to how many innervated the brachialis. 3-6

Donor-site deficits are inconsequential since they only contribute accessory function to inspiration. 4 Far more substantial is the client’s need to perform the inherent action of the nerve to produce muscle activity at the transfer site— meaning muscle recruitment involves a deep breath or Valsalva maneuver. Muscle transfers often utilize the gracilis muscle for a donor muscle due to lack of noticeable deficit once harvested. Unfortunately, the ICN transfer is only 46 percent successful at achieving M4 or M5 function with intact elbow flexion muscles. 4 With gracilis muscle transfer, the success rate is diminished further.

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Research & Presentations

Neurologic therapy protocols for functional improvement of a joint require the therapy be task-specific and high-repetition. 7 Most clients can’t be certain they are activating the muscle consistently because of trace (M1) muscle activity, limited range of motion against gravity (M2), unnatural muscle activation (because of the ICN transfer), and paraesthesia. Old protocols of performing elbow flexion with gravity eliminated invite compensations and frustration due to a lack of feedback. Many clients report being unable to determine whether or not their muscle is even firing, while others become discouraged at the modest gains in arm motion. Utilizing a technology that provides both visual and functional feedback allows the patient to perform reliable muscle activation and pursue functional activity. 8 We utilized a custom-made myoelectric elbow orthosis, the MyoPro (Myomo, Cambridge, Massachusetts) to translate the elbow flexion signals into M4 muscle activity (Figure 2). Sensors housed within the humeral section of the device transcutaneously utilize neurons signalling the intention to move. The client’s muscles amplify the electric activity from the nerves and facilitate transcutaneous detection. With appropriate programming, the muscle activity that is inadequate to produce physiologic elbow motion causes the MyoPro to emulate normal elbow motion.

We understand frequent muscle activation will strengthen the muscle in accord with normal muscle physiology. 9-11 Some measure of neuronal reinforcement or neuroplasticity is also possible. 8 My goal is to explore if a device like the MyoPro may be effective at transforming BPI surgical failures into successes.

Methods Each subject was evaluated for candidacy as prescribed by their physician after persistent functional shortcoming following ICN to MCN brachial plexus

Figure 2 MyoPro Motion-W

treatments. MyoPro candidacy criteria were affirmed as a normal element of the MyoPro evaluation packet (Myomo.com). There were no controls or protocols in place for time of fit following surgery, time since initial injury, wearing schedules, or other notable physiologic or metabolic considerations of each client. Subjects demonstrated their ability to operate the MyoPro consistently and reliably utilizing their available elbow flexor and extensor muscle groups. Each device was initially programmed by emphasizing ease of engaging the elbow motors while managing the electrode sensitivity to minimize exceptionable motor activity.

Each subject’s MMT and Disability of the Arm, Shoulder, and Hand (DASH) scores were procured at the fit appointment. Of our cohort, each subject had spent at least a year in the device.

Each subject’s therapist received the same training protocol of prioritizing proficiency and stamina while operating the MyoPro first, then moving onto functional tasks once proficiency milestones were demonstrated. Therapists were instructed in the fit and adjustment of the MyoPro to accommodate changes in subjects’ muscular condition at the elbow that we anticipated.

Results

Subject 1

The client is a 60-year-old male who presents with bilateral UE weakness from a MVA in June of 2013. He suffered nerve damage at C2 and C5-7, sternal fractures, cervical myelopathy, and spinal cord injury. Bilateral ICN transfers were performed in December of 2013. DASH and MMT Scores taken when he was fit September of 2014 are compared against scores taken 30 months later in May 2017 (Table 1). Every compartment was restored to a functional strength of at least 4. He reports not using his devices for the past several months as they are no longer necessary. His DASH score dropped to 21 percent of what it used to be, with four tasks remaining of 15 formerly listed as “unable.”

Subject 2 The client is a 19-year-old male who suffered a nondominant left-side BPI with C5 rupture, C6 avulsion, and C7-T1 lesion following a motor-vehicle collision with a tree in October of 2014. He underwent left ICN transfer to his natural biceps in December of 2014. We fit him 10 months later in September of 2015.

Figure 3 Subject 1 in therapy

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Research & Presentations

Figure 4

Subject 2 M4 elbow demonstration

Table 1 Client 1 Change in MMT and DASH Scores 9/2014 – 5/2017

MMT

Shoulder

Left

Right

Elbow

Left

Right

Wrist

Left

Right

Flexion

3 → 4

3 → 4

1 → 4

1 → 4

5

5

Extension

3 → 4

3 → 4

2 → 4

2 → 4

5

5

Abduction

3 → 4

3 → 4

Adduction

3 → 4

3 → 4

DASH

Initial

Final

Score

70

15

# of “5”s

15

4

We followed up with the client at our office in October of 2016. He demonstrated M4 muscle strength at the elbow, being able to lift two pounds with full range of motion against gravity (Figure 4). He had already discontinued using the device at this point.

DASH and MMT scores were obtained during his fit appointment and 21 months later in June 2017 (Table 2). The client reported he hasn’t needed the device for months, using it periodically. He regained good control of his elbow and developed poor control at his shoulder. Mild paraesthesia persists in the arm, though the patient reports the numbness is far reduced from where he started. His DASH score is less than half his initial score, and he reports no longer being unable to perform any task.

Subject 3 The client is 23-year-old male, evaluated in February of 2015, who suffered a left nondominant side BPI with C5 rupture, C6-T1 preganglion avulsion, ulnar/ radial fracture with internal fixation, and compartment syndrome secondary to a motorcycle accident in January of 2013. He underwent left ICN transfer to his musculocutaneous nerve in the days immediately following his trauma. He reports being insensate below his elbow.

Table 2 Client 2 Change in MMT and DASH Scores 9/2015 – 6/2017

MMT

Shoulder

Left

Right

Elbow

Left

Right

Wrist

Left

Right

Flexion

1 → 3

5

2 → 4

5

5

5

Extension

2 → 3

5

4

5

5

5

Abduction

1 → 2

5

Adduction

4

5

DASH

Initial

Final

Score

38

18

# of “5”s

3

0

Table 3 Client 3 Change in MMT and DASH Scores 5/2016 – 6/2017

MMT

Shoulder

Left

Right

Elbow

Left

Right

Wrist

Left

Right

Flexion

1 → 2

5

1 → 2

5

0

5

Extension

1 → 2

5

1 → 2

5

0

5

Abduction

1 → 2

5

Adduction

1 → 2

5

DASH

Initial

Final

Score

51

20

# of “5”s

3

0

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Research & Presentations

His paralysis appears flaccid with fixed rigidity in his fused wrist and paralyzed hand. We fit the client in May of 2016 with his MyoPro. He presents similarly to our initial evaluation, despite taking 15 months to be fit.

During a routine follow-up, we noted the EMG signals were acting a bit inconsistently. Ultimately, we decided to send new electrodes out to the client. We may have lost a matter of time because of the issue.

DASH and MMT scores were obtained at the fit appointment and compared to scores taken 13 months later in June of 2017. Of particular note are the client’s deficiencies in any activity requiring more than 80 degrees of shoulder flexion or abduction, which are limitations of the ICN transfer. Mild paraesthesia persists in the arm, though the patient reports the numbness is far reduced from where he started.

Discussion In BPI rehabilitation, a large amount of weight is given to restoring elbow function. 4 Understandably, it is the joint segment that allows the individual the greatest degree of freedom and agency over their immediate environment. Many activities of self-maintenance, interacting with the world and others, and hygiene occur with some coordination of the normal 150 degrees of elbow ROM and shoulder motion. In the cases presented, restoring elbow

function created large reductions in perceived and actual disability.

Across the spectrum of subjects we treated, functional return was seen. Subject 1 recovered from having M1 at the biceps bilaterally for 18 months to M4 at some point within the following 25 months. Subject 2 spent nine months stuck at M2 postbrachial plexus reconstruction. Thirteen months after provision of the device, the client demonstrated M4 muscle activity at the elbow, which he maintained during the next eight months until his testing. Subject 3 had endured M1 activity for 25 months before being fit for his device. He spent the next 13 months developing his elbow to an M3 level. In each case, clients saw dramatic recovery in elbow flexion after provision of the MyoPro. We would like to extrapolate the trend to assume further time in the device for Subject 3 would mean further increases. It’s also worth recognizing that Subject 3 was the only one without functional use of his hand, which could reduce opportunities to use the arm functionally. We are more confident of the impact of the intervention in these clients because they saw no increase in functional elbow motion between surgical intervention and provision of the device.

The DASH is used as a scale to produce a score between absolutely no disability (0) and complete disability (100). Each subject decreased their level of disability compared to their initial

scores. Cases 1, 2, and 3 reduced their DASH scores by 21 percent, 47 percent, and 39 percent respectively. What we can determine from a gross metric like the DASH is some degree of confidence our intervention assisted in reducing each client’s perceived and actual disability by some significant degree. The number of tasks the client was “unable” (an item score of 5) to perform was included to further emphasize the reduction in disability.

Conclusion In some cases, as the nerves reinnervate, spontaneous recovery of function can occur at motor sites. Postsurgical reinnervation primarily occurs within six to 18 months. Many patients evaluated for the myoelectric elbow were no longer candidates after the months between evaluation and delivery of their device due to their recovery to M4 elbow activity without orthotic intervention. Half of all surgical candidates with ICN transfer will never need orthotic management. However, in the cases presented, spontaneous recovery was unlikely to explain each increase in function and reduction of disability due to the massive extent of time between surgical intervention and any functional return.

It is my opinion that the successes presented are due to the distinct nature of activating the device for motion. Unlike other modalities, the action of the orthosis begins with the intent to move, causing muscle recruitment. There is no stimulation. Instead, we are reinforcing neural pathways in line with the principles of neuroplasticity and recruiting muscles in accordance with normal muscle physiology. It is very promising that in the future TBPI clients will have another tool that may salvage functional recovery of their limb once surgical and therapeutic options are exhausted.

David R. Coleman, CPO, FAAOP, works at Limb Lab Prosthetics & Orthotics Co. in Rochester, Minnesota.

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Research & Presentations

References

1. Shin AY, Spinner RJ, Steinman SP, Bishop AT. Adult Traumatic Brachial Plexus Injuries. J Am Acad Orthop Surg. 2005; 13(6):382-396.

2. Midha R. Epidemiology of Brachial Plexus Injuries in a Multitrauma Population. Neurosurgery. June 1997; 40(6):1182-1189.

3. Tung TH, Novak CB, Mackinnon, SE. Nerve Transfers to the Biceps and Brachialis Branches To Improve Elbow Flexion Strength After Brachial Plexus Injuries. J. Neurosurg. 2003; 98:313-318.

4. Gutowski KA, Orenstein HH. Restoration of Elbow Flexion After Brachial Plexus Injury: The Role of Nerve and Muscle Transfers. Plastic and Reconstructive Surgery. 2000; 106(6):1348-1358.

5. Tu Y-K, Tsai Y-J, Chang C-H, Su F-C, Hsiao C-K, Tan JS. Surgical Treatment for Total Root Avulsion Type Brachial Plexus Injury by Neurotisation: A Prospective Comparison Study Between Total and Hemicontralateral C7 Nerve Root Transfer. Microsurgery. 2013; 91-101.

6. Ochiai N, Nagano A, Sugioka H, Hara T. Nerve Grafting in Brachial Plexus Injuries. J Bone Joint Surg. 1996; 78-B:754-758.

7. Taub E, Crago JE, Burgio LD, Groomes TE, Cook EW, DeLuca SC, Miller NE. An Operant Approach to Rehabilitation Medicine: Overcoming Learned Nonuse by Shaping. Journal of Experimental Analysis of Behavior. 1994; 61:281-293.

8. Page SJ, Hill V, White S. Portable Upper-Extremity Robotics Is As Efficacious as Upper-Extremity

Rehabilitation Therapy: A Randomized Control Pillow Trial. Clin Rehabil. June 2013; 27(6):494-503.

9. Kim GJ, Rivera L, Stein J. Combined Clinic-Home Approach for Upper- Limb Robotic Therapy After Stroke: A Pilot Study. Archives of Physical Medicine and Rehabilitation. 2015; 2243-2248.

10. Peters HT, Page SJ, Persch A. Giving Them a Hand: Wearing a Myoelectric Elbow-Wrist-Hand Orthosis Reduces Upper-Extremity Impairment in Chronic Stroke. Archives of Physical Medicine and Rehabilitation. 2017; 1-7.

11. Stein J, Narendran K, McBean J, Krebs K, Hughes R. Electromyography-Controlled Exoskeletal Upper-Limb-Powered Orthosis for Exercise Training After Stroke. Am J of Phys Med & Rehab. 2007; 255-261.

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