Prognostic factors for outcome after median, ulnar, and combined median–ulnar nerve injuries: A prospective study

Early post-surgical rehabilitation and functional outcomes of a traumatic ulnar nerve injury: a pediatric case report

Background

Peripheral nerve injuries (PNIs) of the upper limb are very common events within the pediatric population, especially following soft tissue trauma and bone fractures. Symptoms of brachial plexus nerve injuries can differ considerably depending on the site and severity of injury. Compared to median and radial nerves, the ulnar nerve (UN) is the most frequently and severely injured nerve of the upper extremity. Indeed, due to its peculiar anatomical path, the UN is known to be particularly vulnerable to traumatic injuries, which result in pain and substantial motor and sensory disabilities of the forearm and hand. Therefore, timely and appropriate postoperative management of UN lesions is crucial to avoid permanent sensorymotor deficits and claw hand deformities leading to lifelong impairments. Nevertheless, the literature regarding the rehabilitation following PNIs is limited and lacks clear evidence regarding a solid treatment algorithm for the management of UN lesions that ensures full functional recovery.

Case presentation

The patient is a 11-year-old child who experienced left-hand pain, stiffness, and disability secondary to a domestic accident. The traumatic UN lesion occurred about 8 cm proximal to Guyon's canal and it was surgically treated with termino-terminal (end-to-end) neurorrhaphy. One month after surgery, the patient underwent multimodal rehabilitative protocol and both subjective and functional measurements were recorded at baseline (T0) and at 3- (T1) and 5-month (T2) follow-up. At the end of the rehabilitation protocol, the patient achieved substantial reduction in pain and improvement in quality of life. Of considerable interest, the patient regained a complete functional recovery with satisfactory handgrip and pinch functions in addition with a decrease of disability in activities of daily living.

Conclusion

A timely and intensive rehabilitative intervention done by qualified hand therapist with previous training in the rehabilitation of upper limb neuromuscular disorders is pivotal to achieve a stable and optimal functional recovery of the hand, while preventing the onset of deformities, in patients with peripheral nerve injuries of the upper limb.

Effective Delivery of Vagus Nerve Stimulation Requires Many Stimulations Per Session and Many Sessions Per Week Over Many Weeks to Improve Recovery of Somatosensation

BACKGROUND

Chronic sensory loss is a common and undertreated consequence of many forms of neurological injury. Emerging evidence indicates that vagus nerve stimulation (VNS) delivered during tactile rehabilitation promotes recovery of somatosensation.

OBJECTIVE

Here, we characterize the amount, intensity, frequency, and duration of VNS therapy paradigms to determine the optimal dosage for VNS-dependent enhancement of recovery in a model of peripheral nerve injury (PNI).

METHODS

Rats underwent transection of the medial and ulnar nerves in the forelimb, resulting in chronic sensory loss in the paw. Eight weeks after injury, rats were implanted with a VNS cuff and received tactile rehabilitation sessions consisting of repeated mechanical stimulation of the previously denervated forepaw paired with short bursts of VNS. Rats received VNS therapy in 1 of 6 systematically varied dosing schedules to identify a paradigm that balanced therapy effectiveness with a shorter regimen.

RESULTS

Delivering 200 VNS pairings a day 4 days a week for 4 weeks produced the greatest percent improvement in somatosensory function compared to any of the 6 other groups (One Way analysis of variance at the end of therapy, F[4 70] P = .005).

CONCLUSIONS

Our findings demonstrate that an effective VNS therapy dosage delivers many stimulations per session, with many sessions per week, over many weeks. These results provide a framework to inform the development of VNS-based therapies for sensory restoration.

Outcomes and prognostic factors for nerve grafting following high radial nerve injury

In this study, we examined the prognostic factors affecting outcomes following nerve grafting in high radial nerve injuries. Thirty-three patients with radial nerve injuries at a level distal to the first branch to the triceps and proximal to the posterior interosseous nerve were retrospectively studied. After a follow-up of at least 1 year, 24 patients (73%) obtained M3+ wrist extension, 16 (48%) obtained M3+ finger extension and only ten (30%) obtained M3+ thumb extension. Univariate, multivariate and receiver operating characteristic analyses showed that a delay in the repair of less than 6 months, a defect length of less than 5 cm or when grafted with three or more donor nerve cables achieved better recovery. Number of cables used was related to muscle strength recovery but not time to reinnervation. Nerve grafting for high radial nerve injury achieved relatively good wrist extension but poor thumb extension and is affected by certain prognostic factors.       Level of evidence: IV.

Ulnar-Sided Upper Extremity Traumatic Wounds: What Should We Expect to Find?

Background: Upper limb traumatic injuries have a significant impact on social and professional life; however, there is still a paucity of studies focusing on the injuries of the ulnar border of the forearm, wrist and hand. Methods: We designed a retrospective single-blinded study, including all patients with deep traumatic wounds affecting the ulnar side of the forearm, wrist or hand, that received surgical treatment from 2006 until 2016. A characterisation of the sample, assessment of concomitant injuries and clinical outcomes, as well as neurological and functional evaluation were performed. Results: We obtained a sample of 61 patients, 69% with injuries affecting the wrist and 90% of patients with a neurological lesion, most frequently of the ulnar nerve lesion (UNL). Concomitant injuries included tendinous lesions, more frequently of the flexor carpi ulnaris (64%) and fractures (13%). And 39% of patients presented an ulnar artery lesion, without significant differences in outcomes regarding the completion of arteriorrhaphy or not. At the end of the 8.6 years follow-up, 34% of patients had no deficits; however, patients with UNL showed worse functional scores and greater risk of sequelae. Besides motor function compromise, sensory deficits were also associated with worst functional outcomes. Conclusions: The UNL subgroup showed important impairment of the first ray, probably related to the level of UNL. Furthermore, besides the implications of the motor sequelae, sensory deficits were also associated with worst functional scores. Due to the high percentage of neurovascular and tendinous lesions in ulnar-sided upper extremity wounds, the authors recommend surgical exploration of these lesions. Level of Evidence: Level IV (Therapeutic).

Traumatic peripheral nerve injuries: a classification proposal

BACKGROUND

Peripheral nerve injuries (PNIs) include several conditions in which one or more peripheral nerves are damaged. Trauma is one of the most common causes of PNIs and young people are particularly affected. They have a significant impact on patients' quality of life and on the healthcare system, while timing and type of surgical treatment are of the utmost importance to guarantee the most favorable functional recovery. To date, several different classifications of PNIs have been proposed, most of them focusing on just one or few aspects of these complex conditions, such as type of injury, anatomic situation, or prognostic factors. Current classifications do not enable us to have a complete view of this pathology, which includes diagnosis, treatment choice, and possible outcomes. This fragmentation sometimes leads to an ambiguous definition of PNIs and the impossibility of exchanging crucial information between different physicians and healthcare structures, which can create confusion in the choice of therapeutic strategies and timing of surgery.

MATERIALS

The authors retrospectively analyzed a group of 24 patients treated in their center and applied a new classification for PNI injuries. They chose (a) five injury-related factors, namely nerve involved, lesion site, nerve type (whether motor, sensory or mixed), surrounding tissues (whether soft tissues were involved or not), and lesion type-whether partial/in continuity or complete. An alphanumeric code was applied to each of these classes, and (b) four prognostic codes, related to age, timing, techniques, and comorbidities.

RESULTS

An alphanumeric code was produced, similar to that used in the AO classification of fractures.

CONCLUSIONS

The authors propose this novel classification for PNIs, with the main advantage to allow physicians to easily understand the characteristics of nerve lesions, severity, possibility of spontaneous recovery, onset of early complications, need for surgical treatment, and the best surgical approach.

LEVEL OF EVIDENCE

according to the Oxford 2011 level of evidence, level 2.

Recovery of post-arthrodesis hand function in the interphalan-geal joint - Case presentation

Objectives. The paper highlights the importance of the kinetic recovery program used to regain post-arthrodesis hand function in the interphalangeal joint. Also, during the paper we will present both the techniques used and the methods applied in order to reduce pain and recover the remaining functional. Materials and method. During the study, a patient with open intra-articular communicative fractures AIFP D3, 4 in the right hand with bone-operated defect was analyzed. The patient was evaluated functionally postoperatively, during the recovery program and at the end of it. Results. During the recovery program, a progress and a good evolution of the hand functionality could be observed. Thus, the patient observed the kinetic program initially established by the physiotherapist and also it was possible to observe the increase of the mobility of the joints in the vicinity of the joints affected by the immobilization of the hand. During the recovery program, a decrease in edema was observed locally and an increase in the strength of the muscles of the hand. Conclusions. The physiotherapy program used to restore the functionality of the hand following arthrodesis at the level of the interphalangeal joints must be preceded by an appropriate evaluation and must include techniques adapted to the patient's abilities. An essential condition is a good collaboration between patient-physiotherapist-orthopedic surgeon, so that complications and recurrences can be avoided.

Bilateral Ulnar Nerve Injury in the Wrist: Comparison of First Webspace Muscle Reconstruction by Opponens Nerve Transfer in the Right Hand Versus Direct Ulnar Nerve Repair in the Left Hand

We report a case of a bilateral glass injury to the wrist with transection of flexor tendons and the ulnar nerve and artery in a 60-year-old male patient. Two days after his accident, we repaired all divided structures, and on the right hand, we added the transfer of the opponens motor branch to the deep terminal division of the ulnar nerve aimed at first dorsal interosseous and adductor pollicis muscle reinnervation. After surgery, the patient was followed over 24 months. Postoperative dynamometry of the hand, which included grasping, key-pinch, subterminal-key-pinch, pinch-to-zoom, and first dorsal interosseous muscle strength, indicated recovery only in the nerve transfer side.

Prospective outcome analysis of ulnar tunnel syndrome: Comparing traumatic versus non-traumatic etiologies

BACKGROUND

Ulnar tunnel syndrome (UTS) is relatively uncommon compared to the carpal tunnel or cubital tunnel syndromes. Few reports dedicated to the functional outcomes after surgical intervention of the UTS exist. Herein we compare the outcomes of patients with UTS of different etiologies.

METHODS

Patients diagnosed with UTS between 2016 and 2020 were recruited. Ulnar tunnel release was performed in all patients, along with other necessary osteosynthesis or reconstructive procedures in the traumatic group. Patients were followed-up every six months post-operatively. Outcomes measured include: objective evaluations, subjective questionnaires, records of clinical signs, and grading of the British Medical Research Council scale for intrinsic muscle strength.

RESULTS

21 patients were recruited, and favorable results were noted in all of them after surgery. Traumatic UTS patients had a worse initial presentation than the non-traumatic cases, but had a greater improvement after surgery and yielded outcomes comparable with those of the patients without trauma. Patients with aberrant muscles in their wrists had better outcomes in some objective measurements than those without aberrant muscles.

CONCLUSIONS

Ulnar tunnel release improves the outcome of patients regardless of the etiology, especially in patients with trauma-induced UTS. Thus, a proper diagnosis of the UTS should be alerted in all patients encountering paresthesia in the ulnar digits, ulnar-sided pain, weakness of grip strength, or intrinsic weakness to ensure good outcomes.

Bioengineered nerve conduits and wraps for peripheral nerve repair of the upper limb

BACKGROUND

Traumatic peripheral nerve injury is common and incurs significant cost to individuals and society. Healing following direct nerve repair or repair with autograft is slow and can be incomplete. Several bioengineered nerve wraps or devices have become available as an alternative to direct repair or autologous nerve graft. Nerve wraps attempt to reduce axonal escape across a direct repair site and nerve devices negate the need for a donor site defect, required by an autologous nerve graft. Comparative evidence to guide clinicians in their potential use is lacking. We collated existing evidence to guide the clinical application of currently available nerve wraps and conduits.

OBJECTIVES

To assess and compare the effects and complication rates of licensed bioengineered nerve conduits or wraps for surgical repair of traumatic peripheral nerve injuries of the upper limb. To compare effects and complications against the current gold surgical standard (direct repair or nerve autograft).

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search was 26 January 2022. We searched online and, where not accessible, contacted societies' secretariats to review abstracts from the British Surgical Society of the Hand, International Federation of Surgical Societies of the Hand, Federation of European Surgical Societies of the Hand, and the American Society for Peripheral Nerve from October 2007 to October 2018.

SELECTION CRITERIA

We included parallel group randomised controlled trials (RCTs) and quasi-RCTs of nerve repair in the upper limb using a bioengineered wrap or conduit, with at least 12 months of follow-up.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane procedures. Our primary outcomes were 1. muscle strength and 2. sensory recovery at 24 months or more. Our secondary outcomes were 3. British Medical Research Council (BMRC) grading, 4. integrated functional outcome (Rosén Model Instrument (RMI)), 5. touch threshold, 6. two-point discrimination, 7. cold intolerance, 8. impact on daily living measured using the Disability of Arm Shoulder and Hand Patient-Reported Outcome Measure (DASH-PROM), 9. sensory nerve action potential, 10. cost of the device, and 11. adverse events (any and specific serious adverse events (further surgery)). We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

Five studies involving 213 participants and 257 nerve injuries reconstructed with wraps or conduits (129 participants) or standard repair (128 participants) met the inclusion criteria. Of those in the standard repair group, 119 nerve injuries were managed with direct epineurial repair, and nine autologous nerve grafts were performed. One study excluded the outcome data for the repair using an autologous nerve graft from their analysis, as it was the only autologous nerve graft in the study, so data were available for 127 standard repairs. There was variation in the functional outcome measures reported and the time postoperatively at which they were recorded. Mean sensory recovery, assessed with BMRC sensory grading (range S0 to S4, higher score considered better) was 0.03 points higher in the device group (range 0.43 lower to 0.49 higher; 1 RCT, 28 participants; very low-certainty evidence) than in the standard repair group (mean 2.75 points), which suggested little or no difference between the groups, but the evidence is very uncertain. There may be little or no difference at 24 months in mean touch thresholds between standard repair (0.81) and repair using devices, which was 0.01 higher but this evidence is also very uncertain (95% confidence interval (CI) 0.06 lower to 0.08 higher; 1 trial, 32 participants; very low-certainty evidence). Data were not available to assess BMRC motor grading at 24 months or more. Repair using bioengineered devices may not improve integrated functional outcome scores at 24 months more than standard techniques, as assessed by the Rosén Model Instrument (RMI; range 0 to 3, higher scores better); the CIs allow for both no important difference and a better outcome with standard repair (mean RMI 1.875), compared to the device group (0.17 lower, 95% CI 0.38 lower to 0.05 higher; P = 0.13; 2 trials, 60 participants; low-certainty evidence). Data from one study suggested that the five-year postoperative outcome of RMI may be slightly improved after repair using a device (mean difference (MD) 0.23, 95% CI 0.07 to 0.38; 1 trial, 28 participants; low-certainty evidence). No studies measured impact on daily living using DASH-PROM. The proportion of people with adverse events may be greater with nerve wraps or conduits than with standard techniques, but the evidence is very uncertain (risk ratio (RR) 7.15, 95% CI 1.74 to 29.42; 5 RCTs, 213 participants; very low-certainty evidence). This corresponds to 10 adverse events per 1000 people in the standard repair group and 68 per 1000 (95% CI 17 to 280) in the device group. The use of nerve repair devices may be associated with a greater need for revision surgery but this evidence is also very uncertain (12/129 device repairs required revision surgery (removal) versus 0/127 standard repairs; RR 7.61, 95% CI 1.48 to 39.02; 5 RCTs, 256 nerve repairs; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Based on the available evidence, this review does not support use of currently available nerve repair devices over standard repair. There is significant heterogeneity in participants, injury pattern, repair timing, and outcome measures and their timing across studies of nerve repair using bioengineered devices, which make comparisons unreliable. Studies were generally small and at high or unclear risk of bias. These factors render the overall certainty of evidence for any outcome low or very low. The data reviewed here provide some evidence that more people may experience adverse events with use of currently available bioengineered devices than with standard repair techniques, and the need for revision surgery may also be greater. The evidence for sensory recovery is very uncertain and there are no data for muscle strength at 24 months (our primary outcome measures). We need further trials, adhering to a minimum standard of outcome reporting (with at least 12 months' follow-up, including integrated sensorimotor evaluation and patient-reported outcomes) to provide high-certainty evidence and facilitate more detailed analysis of effectiveness of emerging, increasingly sophisticated, bioengineered repair devices.

Assessment of Motor Function in Peripheral Nerve Injury and Recovery

Introduction

Peripheral nerve injuries can be difficult to diagnose, treat, and monitor given their highly variable presentation. When the status of nerves is not accurately assessed, treatment may be delayed or overlooked and can result in lasting functional deficits. As our understanding of nerve repair and generation evolves, so will tools for evaluating both the functional and morphological status of peripheral nerves.

Objective

There is currently no single article which provides a detailed, comprehensive view of the literature comparing the clinical utility of various assessment modalities. Furthermore, there is no consensus on the optimal assessment algorithm for peripheral nerve injuries.

Methods

We performed a literature review using a comprehensive combination of keywords and search algorithm. The search was focused on clinical data regarding the assessment of peripheral nerves Results: This review may help to determine the appropriate tools that are currently available for monitoring nerve function both pre and postoperatively. Additionally, the review demonstrates possible roles and areas of improvement for each tool used to assess motor function.

Conclusion

As surgeons work to improve treatments for peripheral nerve injury and dysfunction, identifying the most appropriate existing measures of success and future directions for improved algorithms could lead to improved patient outcomes.

Cold sensitivity and its association to functional disability following a major nerve trunk injury in the upper extremity—A national registry-based study

Aims

To investigate self-reported cold sensitivity and functional disability after a repaired major nerve trunk injury in the upper extremity.

Methods

We identified 735 individuals with a major nerve trunk injury in the upper extremity, surgically treated with direct nerve repair or reconstructed with nerve autografts, in the Swedish national quality registry for hand surgery (HAKIR). Patient-reported symptoms, including cold sensitivity, and perceived disability were collected using two questionnaires (HQ-8 and QuickDASH) preoperatively, and at three and 12 months postoperatively.

Results

We included 281 individuals, who had responded the questionnaires, where 197 (70%) were men (median age 34 [interquartile range 25–52] years) and 84 (30%) were women (median age 41 [25–55]). Cold sensitivity (scored 0–100) was the most prominent symptom 12 months postoperatively after an injured and repaired/reconstructed median (p<0.001) or ulnar (p<0.001) nerve, while individuals with a radial nerve injury showed milder symptoms. Concomitant injuries did not affect cold sensitivity scores. Individuals with ulnar nerve injuries scored higher in stiffness (p = 0.019), weakness (p<0.001) and ability to perform daily activities (p = 0.003) at 12 months postoperatively than median nerve injuries. Individuals with a median, ulnar or radial nerve injury with severe (>70) cold sensitivity had 25, 37 and 30 points higher QuickDASH scores, respectively (p<0.001), at 12 months postoperatively than individuals with mild (<30) cold sensitivity. There were no differences in QuickDASH score or cold sensitivity score at 12 months postoperatively between direct nerve repair or nerve reconstruction with nerve autografts. Neither age, nor sex, affected QuickDASH score at 12 months postoperatively.

Conclusion

Cold sensitivity after surgery for a major nerve trunk injury in the upper extremity can be substantial with impaired ability to perform daily activities, where an ulnar nerve injury may have a worse outcome.

Greater Cortical Activation and Motor Recovery Following Mirror Therapy Immediately after Peripheral Nerve Repair of the Forearm

Cortical reorganization occurs immediately after peripheral nerve injury, and early sensorimotor training is suggested during nerve regeneration. The effect of mirror therapy and classical sensory relearning on cortical activation immediately after peripheral nerve repair of the forearm is unknown. Six participants were randomly assigned to the mirror-therapy group or the sensory-relearning group. Sensorimotor training was conducted in a mirror box for 12 weeks. The mirror-therapy group used mirror reflection of the unaffected hand in order to train the affected hand, and the sensory-relearning group trained without mirror reflection. Semmes-Weinstein Monofilaments (SWM) test, static 2-point discrimination test (S-2PD), grip strength, and the Disabilities of the Arm, Shoulder and Hand (DASH) scores were measured at baseline, the end of the intervention (T1), and 3 months after the intervention (T2). Finger and manual dexterity were measured at T1 and T2, and a functional MRI (fMRI) was conducted at T1. All participants showed improvement in the SWM, S-2PD tests, upper extremity function, and grip strength after the intervention at T1, except for the participant who injured both the median and ulnar nerves in the sensory-relearning group. In addition, the mirror-therapy group had better outcomes in finger dexterity and manual dexterity, and fMRIs showed greater activation in the multimodal association cortices and ipsilateral brain areas during motor tasks. This study provides evidence-based results confirming the benefits of early sensorimotor relearning for cortical activation in peripheral nerve injury of the forearm and different neuroplasticity patterns between mirror therapy and classical sensor relearning.

Beyond the Knife-Reviewing the Interplay of Psychosocial Factors and Peripheral Nerve Lesions

Peripheral nerve injuries are a common clinical problem. They not only affect the physical capabilities of the injured person due to loss of motor or sensory function but also have a significant impact on psychosocial aspects of life. The aim of this work is to review the interplay of psychosocial factors and peripheral nerve lesions. By reviewing the published literature, we identified several factors to be heavily influenced by peripheral nerve lesions. In addition to psychological factors like pain, depression, catastrophizing and stress, social factors like employment status and worker's compensation status could be identified to be influenced by peripheral nerve lesions as well as serving as predictors of functional outcome themselves, respectively. This work sheds a light not only on the impact of peripheral nerve lesions on psychosocial aspects of life, but also on the prognostic values of these factors of functional outcome. Interdisciplinary, individualized treatment of patients is required to identify patient at risk for adverse outcomes and provide them with emotional support when adapting to their new life situation.

Neuralgic amyotrophy

PURPOSE OF REVIEW

This review focuses on the current insights and developments in neuralgic amyotrophy (NA), an auto-immune multifocal peripheral nervous system disorder that leaves many patients permanently impaired if not recognized and treated properly.

RECENT FINDINGS

NA is not as rare as previously thought. The phenotype is broad, and recent nerve imaging developments suggest that NA is the most common cause of acute anterior or posterior interosseous nerve palsy. Phrenic nerve involvement occurs in 8% of all NA patients, often with debilitating consequences. Acute phase treatment of NA with steroids or i.v. immunoglobulin may benefit patients. Long-term consequences are the rule, and persisting symptoms are mainly caused by a combination of decreased endurance in the affected nerves and an altered posture and movement pattern, not by the axonal damage itself. Patients benefit from specific rehabilitation treatment. For nerves that do not recover, surgery may be an option.

SUMMARY

NA is not uncommon, and has a long-term impact on patients' well-being. Early immunomodulating treatment, and identifying phrenic neuropathy or complete nerve paralysis is important for optimal recovery. For persistent symptoms a specific treatment strategy aiming at regaining an energy balance and well-coordinated scapular movement are paramount.

Impact of Body Mass Index and Comorbidities on Outcomes in Upper Extremity Nerve Transfers

BACKGROUND

 There is a paucity of research investigating the impact of patient comorbidities, such as obesity and smoking, on nerve transfer outcomes. The objective of this retrospective cohort study was to evaluate the impact of body mass index (BMI) and comorbidities on the clinical outcomes of upper extremity nerve transfers.

METHODS

 A retrospective cohort study was executed. Patients were eligible for inclusion if they had an upper extremity nerve transfer with a minimum of 12-months follow-up. Data was collected regarding demographics, comorbidities, injury etiology, nerve transfer, as well as preoperative and postoperative clinical assessments. The primary outcome measure was strength of the recipient nerve innervated musculature. Statistical analysis used the Mann-Whitney U test, Wilcoxon signed-rank test, and Spearman's rho.

RESULTS

 Thirty-eight patients undergoing 43 nerve transfers were eligible for inclusion. Patients had a mean age of 48.8 years and a mean BMI of 27.4 kg/m² (range:19.7-39.0). Injuries involved the brachial plexus (32%) or its terminal branches (68%) with the most common etiologies including trauma (50%) and compression (26%). Anterior interosseous nerve to ulnar motor nerve (35%) was the most common transfer performed. With a mean follow-up of 20.1 months, increased BMI (p = 0.036) and smoking (p = 0.021) were associated with worse postoperative strength.

CONCLUSION

 This retrospective cohort study demonstrated that increased BMI and smoking may be associated with worse outcomes in upper extremity nerve transfers-review of the literature yields ambiguity in both regards. To facilitate appropriate patient selection and guide expectations regarding prognosis, further experimental and clinical work is warranted.

Chronic neuropathic pain after traumatic peripheral nerve injuries in the upper extremity: prevalence, demographic and surgical determinants, impact on health and on pain medication

Background and aims Aside from the long term side effects of a nerve injury in the upper extremity with devastating consequences there is often the problem of chronic neuropathic pain. The studies concerning the prevalence of persistent pain of neuropathic origin after peripheral nerve injuries are sparse. The prevalence and risk factors associated with chronic neuropathic pain after nerve injuries in the upper extremity were assessed. Methods A standardized data collection template was employed prospectively and retrospectively for all patients with traumatic nerve injuries accepted at the Hand Surgery Department, Uppsala, Sweden between 2010 and 2018. The template included demographic data, pain diagnosis, type of injured nerve, level of injury, date of the lesion and repair, type of procedure, reoperation, time since the procedure, S-LANSS questionnaire (Self report-Leeds Assessment of Neuropathic Symptoms and Signs), RAND-36 (Item short form health survey), QuickDASH (Disability of Shoulder, Arm and Hand) and additional questionnaires concerned medication, pain intensity were sent to 1,051 patients with nerve injuries. Partial proportional odds models were used to investigate the association between persistent pain and potential predictors. Results More than half of the patients undergoing a surgical procedure developed persistent pain. Prevalence of neuropathic pain was 73% of the patients with pain (S-LANSS ≥ 12 or more). Multivariate analysis indicated that injury of a major nerve OR 1.6 (p = 0.013), years from surgery OR 0.91 (p = 0.01), younger age OR 0.7 (p < 0.001), were the main factors for predicting pain after surgery. The type of the nerve injured was the strongest predictor for chronic pain with major nerves associated with more pain (p = 0.019). Conclusions A high prevalence of chronic pain and neuropathic pain with a negative impact on quality of life and disability were found in patients after traumatic nerve injury. Major nerve injury, younger age and less time from surgery were predictors for chronic pain.

Acute and long-term costs of 268 peripheral nerve injuries in the upper extremity

Background

Peripheral nerve injury in the upper extremity is linked to high socioeconomic burden, yet cost-analyses are rare and from small cohorts. The objective of this study was to determine the costs and long-term socioeconomic effects of peripheral nerve injuries in the upper extremity in Germany.

Methods

We analyzed data of 250 patients with 268 work-related upper extremity nerve injuries from acute treatment to long-term follow-up on rehabilitation, sick-leave and disability-pension.

Results

Patients were on average 39.9±14.2 years old, male (85%) and mean inpatient treatment was 7±6 days. Location of nerve was 8% (N = 19) proximal to the wrist, 26% (N = 65) at the wrist and metacarpus, and 66% (N = 166) at phalangeal level. Acute in-patient treatment for (single) median nerve injury accounted for 66% with hospital reimbursement of 3.570€, ulnar nerve injury for 24% and 2.650€ and radial nerve injury for 10% and 3.166€, all including finger nerve injuries. The remaining were combined nerve injuries, with significantly higher costs, especially if combined with tendon 5.086€ or vascular injury 4.886€. Based on location, nerve injuries proximal to the wrist averaged 5.360±6.429€, at the wrist and metacarpus 3.534±2.710€ and at the phalangeal level 3.418±3.330€. 16% required rehabilitation with average costs of 5.842€ and stay of 41±21 days. Sick leave was between 11–1109 days with an average of 147 days with socioeconomic costs of 197€/day, equaling on average 17.640€. 30% received a mean yearly disability pension of 3.187€, that would account to 102.167€ per lifetime.

Conclusion

This large German patient sample indicates that nerve injury has a major impact on function and employment, resulting in significant health care costs. Both proximal and distal nerve injuries led to long-term disability, subsequent sick-leave and in 30% to permanent disability pension. These data are determined to support future studies and health economical work on prevention, treatment and rehabilitation of these often small injuries with great consequences.

Outcomes and Return to Work Following Complex Nerve Lacerations in the Volar Forearm in an Underserved Spanish-Speaking Population

Purpose

Lacerations to the ulnar and median nerve in the volar forearm have demonstrated considerable long-term clinical and socioeconomic impacts on patients. The purpose of this study was to evaluate the outcomes of complex volar forearm lacerations involving one or more major peripheral nerves in an economically disadvantaged patient population.

Methods

In this study, a retrospective analysis of 61 patients who sustained lacerations to the median nerve, ulnar nerve, or both with volar wrist lacerations was performed. Each patient’s preinjury and postinjury occupation, dominant extremity, and demographic variables were evaluated. Sensation recovery, motor recovery, Disabilities of the Arm, Shoulder, and Hand scores, visual analog scale scores, cold intolerance, and return to work were evaluated at 3, 6, and 12 months after the injury.

Results

Patients with isolated median nerve injuries demonstrated improved motor recovery compared with patients with isolated ulnar nerve injuries. Patients with combined nerve injuries had worse sensation recovery and motor recovery, and lower rates of return to work than either group of patients with isolated nerve injuries. Manual laborers had worse motor recovery and lower rates of return to work than did patients who were office workers.

Conclusions

Patients with combined median and ulnar nerve injuries have worse functional recovery and lower rates of return to work than do patients with isolated median or isolated ulnar nerve injuries at 1 year. Manual laborers demonstrated worse functional recovery and lower rates of return to work compared with office workers at 1 year.

Type of study/level of evidence

Therapeutic III.

Distal nerve transfer for thenar palsy: A cadaveric study

INTRODUCTION

Severe proximal median nerve palsies often result in irreversible thenar atrophy and thumb abduction function loss. Tendon transfer involves substantial limitations and challenges; but, distal nerve transfer may provide an alternative treatment. Our goal was to validate the anatomical suitability of two distal ulnar nerve branches for thenar muscle reanimation.

MATERIALS AND METHODS

We assessed nerve transfer to the recurrent branch of median nerve (RMN) in 16 embalmed cadaveric hands. The ulnar motor branch to the flexor digiti minimi brevis (FDMBn) and the ulnar motor branch to the third lumbrical (3rdLn) were assessed for transfer. Coaptation success was measured by the overlap of the nerve donor with the RMN and correspondence of nerve diameters.

RESULTS

The mean transferable length and width of the RMN were 20.7 ± 4.5 and 1.0 ± 0.3 mm, respectively. We identified an average of three branches in the branching anatomy from the ulnar nerve to the hypothenar muscles. The maximal transferable lengths and widths of the FDMBn and the 3rdLn were 13.8 ± 4.4 and 0.5 ± 0.1 mm and 24.1 ± 6.4 and 0.4 ± 0.1 mm, respectively. The overlap with the RMN of the FDMBn and 3rdLn was 9.0 ± 3.6 (2.0-15.3) and 17.8 ± 6.0 (4.7-27.5) mm, respectively.

CONCLUSIONS

This anatomical study demonstrates the feasibility of distal nerve transfers between the ulnar and median nerves in the hand for reanimation of thenar muscles. Ulnar motor donors of the BrFDMBn and 3rdLn likely represent the least morbid donors with short distances for regeneration and a single coaptation repair.

Age-Dependent Schwann Cell Phenotype Regulation Following Peripheral Nerve Injury

BACKGROUND

Schwann cells are integral to the regenerative capacity of the peripheral nervous system, which declines after adolescence. The mechanisms underlying this decline are poorly understood. This study sought to compare the protein expression of Notch, c-Jun, and Krox-20 after nerve crush injury in adolescent and young adult rats. We hypothesized that these Schwann cell myelinating regulatory factors are down-regulated after nerve injury in an age-dependent fashion.

METHODS

Adolescent (2 months old) and young adult (12 months old) rats (n = 48) underwent sciatic nerve crush injury. Protein expression of Notch, c-Jun, and Krox-20 was quantified by Western blot analysis at 1, 3, and 7 days post-injury. Functional recovery was assessed in a separate group of animals (n = 8) by gait analysis (sciatic functional index) and electromyography (compound motor action potential) over an 8-week post-injury period.

RESULTS

Young adult rats demonstrated a trend of delayed onset of the dedifferentiating regulatory factors, Notch and c-Jun, corresponding to the delayed functional recovery observed in young adult rats compared to adolescent rats. Compound motor action potential area was significantly greater in adolescent rats relative to young adult rats, while amplitude and velocity trended toward statistical significance.

CONCLUSIONS

The process of Schwann cell dedifferentiation following peripheral nerve injury shows different trends with age. These trends of delayed onset of key regulatory factors responsible for Schwann cell myelination may be one of many possible factors mediating the significant differences in functional recovery between adolescent and young adult rats following peripheral nerve injury.

Polyethylene Glycol: The Future of Posttraumatic Nerve Repair? Systemic Review

Peripheral nerve injury is a common posttraumatic complication. The precise surgical repair of nerve lesion does not always guarantee satisfactory motor and sensory function recovery. Therefore, enhancement of the regeneration process is a subject of many research strategies. It is believed that polyethylene glycol (PEG) mediates axolemmal fusion, thus enabling the direct restoration of axon continuity. It also inhibits Wallerian degeneration and recovers nerve conduction. This systemic review, performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, describes and summarizes published studies on PEG treatment efficiency in various nerve injury types and repair techniques. Sixteen original experimental studies in animal models and one in humans were analyzed. PEG treatment superiority was reported in almost all experiments (based on favorable electrophysiological, histological, or behavioral results). To date, only one study attempted to transfer the procedure into the clinical phase. However, some technical aspects, e.g., the maximal delay between trauma and successful treatment, await determination. PEG therapy is a promising prospect that may improve the surgical treatment of peripheral nerve injuries in the clinical practice.

Factors associated with limited hand motion after hand trauma

Hand injuries are common and have a significant impact on daily life. However, the factors associated with functional outcome after hand injuries are not well established. The purpose of this study was to identify factors that are independently associated with hand total active motion (TAM).A total of 50 patients with unilateral complex hand injury were included in this study. The associations between various demographic, injury-related, and clinical assessment factors and TAM were determined by univariate and multivariate linear regression analyses. Nerve injuries recognized during surgery and diagnosed with electrodiagnostic (EDX) studies were compared using Pearson chi-squared test.Among multiple injury-related and initial clinical assessment factors, nerve injury diagnosed with EDX studies, hospital stay length, elevated C-reactive protein, and skeletal injury were independently associated with TAM in the affected hand after adjusting for covariates. Nerve injuries diagnosed with EDX studies were not consistent with those recognized during surgery.Our results suggest that high-energy trauma leading to skeletal and nerve injury with inflammation is associated with limited hand motion after surgery and postoperative immobilization. A comprehensive EDX study may enable identifying occult or recovered nerve injuries, which would be helpful in understanding limitations in finger movements.

A Population-Based Assessment of Depression and Anxiety in Patients With Brachial Plexus Injuries

PURPOSE

Reactive depression and anxiety are common after major life changes such as brachial plexus injuries (BPI). The purpose of this study was to evaluate the incidence and risk factors for coded depression and coded anxiety among patients with BPI using a national database of commercial insurance claims.

METHODS

We used the Truven MarketScan database from 2007 to 2013 to identify commercially insured patients aged 18 to 64 years who underwent BPI surgery. For comparison, a control group without BPI was frequency-matched 10:1 by age group, sex, number of provider visits, and length of insurance enrollment. Using International Classification of Diseases, Ninth Revision diagnosis codes and pharmacy claims, we identified coded depression and coded anxiety in the 12 months before and 12 months after BPI surgery. Multivariable Cox regression models were used to determine risk factors for coded depression or coded anxiety, adjusting for known risk factors for depression or anxiety (eg, alcohol, substance abuse).

RESULTS

We identified 1,843 patients with BPI and 18,430 controls. Within the 12 months preceding surgery, coded depression and coded anxiety were present in 38% and 42%, respectively, of the BPI group; both were present in 25% and either was present in 54%. The rate of new-onset/postoperatively coded depression among patients with BPI was 142.1/1,000 person-years (12%) and of new-onset/postoperatively coded anxiety was 273.6/1,000 person-years (20%). Patients with BPI were significantly more likely than controls to develop new-onset/postoperatively coded depression (hazard ratio = 1.3; confidence interval [CI], 1.1-1.5) and new-onset/postoperatively coded anxiety (HR = 2.1 [CI, 1.8-2.4]).

CONCLUSIONS

Patients undergoing BPI surgery have a high prevalence of coded depression and coded anxiety in the 12 months before surgery and are at higher risk for developing new-onset/postoperatively coded depression and coded anxiety within 1 year after surgery. These findings can be used by BPI surgeons to inform perioperative counseling, guide emotional recovery from injury, and facilitate coordinated or colocated care with mental health professionals.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Intraoperative compound muscle action potentials (CMAPs) amplitude changes after decompression and neurolysis of peripheral nerves in upper limbs neuropathies: electrophysiologial considerations and relation with clinical outcome

BACKGROUND

Decompression and, when necessary, neurolysis in entrapment neuropathies of upper limbs are effective and safe procedures, but their correlation with the variation of compound muscle action potentials (CMAPs) is still unclear, based in particular on experimental models. In addition, there are few data regarding the efficacy of intraoperative neurophysiologic monitoring (IOM) to predict clinical early and late outcome after surgery in term of pain control and sensitive/motor recovery. We report about the association between the intraoperative anatomical and neurophysiological findings and the mid- and long-term postoperative clinical course in a surgical series.

METHODS

We retrospectively reviewed clinical data of 24 patients among 68 admitted at our Institution for upper limb neuropathies from September 2012 to May 2015. All patients completed two preoperative questionnaires for assessing the level of disability (DASH) and of pain/discomfort (NRS). CMAPs' amplitudes were intraoperatively detected, before and after decompression and neurolysis and the variations were then related to clinical outcome, evaluated through DASH and NRS questionnaires at 6-, 9- and 12-months follow-up.

RESULTS

A statistically significant difference was noted in CMAPs amplitudes before and after decompression (P<0.01). In two patients, this variation was so satisficing to determinate the end of procedure, without the need to perform neurolysis. Major correlations between the variation of CMAPs amplitude after surgery and change of DASH and NRS scores at follow-up were found.

CONCLUSIONS

Variations of CMAPs amplitude provide real-time information on nerves function and may be helpful in predicting mid- and long-term postoperative outcome regarding pain relief and neurological functions.

Ultrasound Diagnosis of Postoperative Complications of Nerve Repair

BACKGROUND

Peripheral nerve injuries often undergo surgical repair, but poor postoperative functional recovery is frequently observed.

CASE DESCRIPTION

We describe 4 cases of traumatic nerve lesions in whom postoperative recovery was prevented by complications such as detachment of nerve sutures or neuroma growth. To the best of our knowledge, no similar cases have been reported in literature so far. It is important to obtain an early diagnosis of such condition because it prevents recovery and delays reintervention, which should be performed before complete muscle denervation and atrophy.

CONCLUSION

Nerve ultrasound is a valuable tool in traumatic nerve injury and has proven to be useful in postoperative follow-up, especially in diagnosing surgical complications such as detachment of nerve direct sutures.

Optimal timing for repair of peripheral nerve injuries

BACKGROUND

Data regarding outcomes after peripheral nerve injuries is limited, and the optimal management strategy for an acute injury is unclear. The aim of this study was to examine timing of repair and specific factors that impact motor-sensory outcomes after peripheral nerve injury.

METHODS

This was a single-center, retrospective study. Patients with traumatic peripheral nerve injury from January 2010 to June 2015 were included. Patients who died, required amputation, suffered brachial plexus injury, or had missing motor-sensory examinations were excluded. Motor-sensory examinations were graded 0 to 5 by the Modified British Medical Research Council system. Operative repair of peripheral nerves was analyzed for patient characteristics, anatomic nerve injured, level of injury, associated injuries, days until repair, and repair method.

RESULTS

Three hundred eleven patients met inclusion criteria. Two hundred fifty-eight (83%) patients underwent operative management, and 53 (17%) underwent nonoperative management. Those who required operative intervention had significantly more penetrating injuries 85.7% versus 64.2% (p < 0.001), worse initial motor scores 1.19 versus 2.23 (p = 0.004), and worse initial sensory examination scores 1.75 versus 2.28 (p = 0.029). Predictors of improved operative motor outcomes on univariate analysis were Injury Severity Score less than 15 (p = 0.013) and male sex (p = 0.006). Upper arm level of injury was a predictor of poor outcome (p = 0.041). Multivariate analysis confirmed male sex as a predictor of good motor outcome (p = 0.014; Adjusted Odds Ratio, 3.88 [1.28-11.80]). Univariate analysis identified distal forearm level of injury (p = 0.026) and autograft repair (p = 0.048) as predictors of poor sensory outcome. Damage control surgery for unstable patients undergoing laparotomy (p = 0.257) and days to nerve repair (p = 0.834) did not influence motor-sensory outcome. Outcomes did not differ significantly in patients who underwent repair 24 hours or longer versus those who were repaired later.

CONCLUSION

Outcomes were primarily influenced by patient characteristics and injury level rather than operative characteristics. Peripheral nerve injuries can be repaired after damage control surgery without detriment to outcomes.

LEVEL OF EVIDENCE

Prognostic study, level III.

A population-based study of injuries to the brachial plexus and to the peripheral nerves of the shoulder girdle and upper limb in the Italian region Friuli Venezia Giulia

The aim of this study was to estimate the incidence, identify the causes, and explore treatments of the injuries to the brachial plexus and peripheral nerves of the shoulder girdle and upper limb in the 1,220,000-inhabitant Italian region Friuli Venezia Giulia.We linked at the individual patient level various administrative databases using an anonymous stochastic key: list of residents, hospital discharge, emergency department, and outpatient care prescriptions database. We abstracted hospital discharge records with at least one discharge diagnosis code ICD-9-CM 953.4 (brachial plexus) or 955.0-955.9 (upper limb). For hospitalized patients, we investigated the prescriptions of ambulatory care during the following year. Emergency department visits in the month prior to hospital admission were also assessed.From 2000 to 2015, we observed 474 hospitalizations (annual average: 61); 48% of patients received at least one prescription of outpatient physical therapy and rehabilitation in the following year, accounting for more than 25,000 visits and interventions. According to emergency department data, falls were the most common mechanism among the elderly; cuts were common among the young.This is the first population study of peripheral nerve injuries to the brachial plexus and peripheral nerves of the shoulder girdle and upper limb in Italy.

Predictors of radial nerve palsy recovery in humeral shaft fractures: A retrospective review of 17 patients

BACKGROUND

Radial nerve injury is common in humeral shaft fractures and fails to recover spontaneously in 30% of cases. Few studies have evaluated predictors of recovery. The objectives of this study were to identify predictors of radial nerve palsy recovery and to assess the usefulness of surgical radial nerve exploration in patients with preoperative radial nerve palsy.

HYPOTHESIS

Factors predicting the outcome of radial nerve palsy can be identified.

METHODS

Of 373 patients with humeral shaft fractures between 2005 and 2012, 43 had radial nerve palsy, including 23 who were lost to follow-up and 17 who were evaluated retrospectively at a mean of 26 months (range, 12-84 months) after internal fixation. The following were studied: age, smoking history, energy of the trauma, fracture type and displacement, skin integrity and intra-operative appearance of the radial nerve.

RESULTS

Of the 17 palsies, 13 were present preoperatively, including 10 that recovered (PreR group) and 3 that did not recover (PreNR group). Plate fixation and radial nerve exploration were performed in all patients. Of the 10 PreR patients, 6 had nerve contusion and 2-nerve entrapment. Of the 3 PreNR patients, 2 had gross nerve damage and 1 nerve contusion and a history of spinal muscular atrophy. Only age and presence of gross nerve damage differed significantly between the PreR and PreNR groups; trends towards significant differences were noted for skin breach and fracture displacement. Of the 4 postoperative radial nerve palsies, 2 recovered fully and 2 partially; mean age was higher in the 2 patients with partial recovery.

DISCUSSION

These findings are consistent with the few previous studies of outcome predictors in radial nerve palsy. Factors such as major fracture displacement and high-grade skin wounds probably promote the occurrence of gross nerve lesions. The high incidence of nerve entrapment and stretching supports routine nerve exploration during internal fixation in patients with preoperative radial nerve palsy.

LEVEL OF EVIDENCE

IV, retrospective study with no control group.

Transfer of the extensor indicis proprius branch of posterior interosseous nerve to reconstruct ulnar nerve and median nerve injured proximally: an anatomical study

Proximal or middle lesions of the ulnar or median nerves are responsible for extensive loss of hand motor function. This occurs even when the most meticulous microsurgical techniques or nerve grafts are used. Previous studies had proposed that nerve transfer was more effective than nerve grafting for nerve repair. Our hypothesis is that transfer of the posterior interosseous nerve, which contains mainly motor fibers, to the ulnar or median nerve can innervate the intrinsic muscles of hands. The present study sought to investigate the feasibility of reconstruction of the deep branch of the ulnar nerve and the thenar branch of median nerve by transferring the extensor indicis proprius branch of the posterior interosseous nerve obtained from adult cadavers. The results suggested that the extensor indicis proprius branch of the posterior interosseous nerve had approximately similar diameters and number of fascicles and myelinated nerve fibers to those of the deep branch of ulnar nerve and the thenar branch of the median nerve. These confirm the feasibility of extensor indicis proprius branch of posterior interosseous nerve transfer for reconstruction of the deep branch of the ulnar nerve and the thenar branch of median nerve. This procedure could be a novel and effective method for the functional recovery of the intrinsic muscles of hands after ulnar nerve or median nerve injury.

Delayed Repair of Ulnar Artery at the Distal Forearm

Background:The purpose of this study was to evaluate the rate of patency after delayed repair of the ulnar artery following primary ligation. Methods: Adult patients with primary ligation of the injured ulnar artery at the forearm who had a delayed repair of the artery were included. Postoperative arterial patency was determined by either physical examination or color Doppler ultrasonographic imaging. Postoperative complications and Disabilities of the Arm, Shoulder and Hand score were recorded. Results: Eight consecutive patients during a 3-year period were included. The mean age was 35 years. Four cases were women. The surgery was performed at a mean of 5 days after the injury and ligation. At a mean follow-up of 22 months, 7 patients had a patent artery. One patient suffered a hematoma. Conclusions: A high rate of patency can be obtained after delayed repair of the ulnar artery at the forearm.

Psychological consequences of traumatic upper limb peripheral nerve injury: A systematic review

Introduction

Traumatic upper limb peripheral nerve injuries significantly impact individuals’ function and ability to return to work. Patients with peripheral nerve injury experience ongoing psychological impairments for which they are not routinely treated. The aim of this review was to investigate the psychological consequences of traumatic upper limb peripheral nerve injury.

Methods

A systematic review of MEDLINE, Embase, PsycINFO, CINAHL, AMED, BNI, the Cochrane libraries and grey literature up to October 2015 was undertaken. Two reviewers independently assessed methodological quality in accordance with Cochrane Collaboration recommendations. Eligibility criteria comprised: adults or adolescents with traumatic upper limb peripheral nerve injury using any measurement of psychological well-being.

Results

Six studies ( n = 245) met the inclusion criteria. Methodological quality varied widely. Evidence of post-traumatic stress disorder at one month, which decreased over time, was reported in three studies. Two studies found a statistically significant correlation between the early presence of post-traumatic stress disorder and reduction in function at 12 or more months. Limited information was available on anxiety, depression and mental quality of life. Combined nerve injuries (in two studies) had significantly higher levels of post-traumatic stress disorder, at one month, compared to those with an isolated nerve injury.

Conclusion

There is some evidence of early post-traumatic stress disorder following traumatic upper limb peripheral nerve injury, which may have an impact on functional outcome. However, high-quality studies using prospective cohorts are required to further evaluate the psychological aspects associated with this traumatic injury.

Effects of age and insulin-like growth factor-1 on rat neurotrophin receptor expression after nerve injury

INTRODUCTION

Neurotrophin receptors, such as p75(NTR) , direct neuronal response to injury. Insulin-like growth factor-1 receptor (IGF-1R) mediates the increase in p75(NTR) during aging. The aim of this study was to examine the effect of aging and insulin-like growth factor-1 (IGF-1) treatment on recovery after peripheral nerve injury.

METHODS

Young and aged rats underwent tibial nerve transection with either local saline or IGF-1 treatment. Neurotrophin receptor mRNA and protein expression were quantified.

RESULTS

Aged rats expressed elevated baseline IGF-1R (34% higher, P = 0.01) and p75(NTR) (68% higher, P < 0.01) compared with young rats. Post-injury, aged animals expressed significantly higher p75(NTR) levels (68.5% above baseline at 4 weeks). IGF-1 treatment suppressed p75(NTR) gene expression at 4 weeks (17.2% above baseline, P = 0.002) post-injury.

CONCLUSIONS

Local IGF-1 treatment reverses age-related declines in recovery after peripheral nerve injuries by suppressing p75(NTR) upregulation and pro-apoptotic complexes. IGF-1 may be considered a viable adjuvant therapy to current treatment modalities. Muscle Nerve 54: 769-775, 2016.