Sensory relearning after nerve repair

[Microsurgical nerve repair]

Substantial nerve lesions almost always lead to persistent functional deficits, even with ideal treatment. Nerve lesions commonly occur in young patients, are often part of complex injuries, and are repeatedly diagnosed and treated with delay. Functional outcome crucially depends on early and adequate treatment. The aim of surgical treatment is a precise and tension-free microsurgical restoration of nerve continuity in a vital and healthy tissue environment. Adequate microsurgical treatment with differentiated postoperative treatment can result in an excellent clinical outcome, even after a delayed diagnosis.

"Voiceless Pain"-Assessment of Pain in Patients with Obstetric Brachial Plexus Injuries: A Retrospective, Single Center Analysis

BACKGROUND

Obstetric brachial plexus injuries (OBPIs) not only lead to severe and life changing sequelae regarding motor impairment but can also be responsible for multi-characteristic pain. In everyday routine, questions regarding pain of the developing child with an OBPI are often overseen and neglected. We aimed to elucidate this specific question and analyzed all patients with OBPI treated in our center to unmask initially non-observed pain and ultimately put pain in correlation to the surgical reconstructive treatment performed.

METHODS

This single center retrospective study analyzes patients with OBPI treated in our center over the past 20 years. Patients were surveyed by the adolescent pediatric pain tool assessment to evaluate pain over their entire life span by excluding potential postoperative pain episodes.

RESULTS

A total of 95 patients were initially contacted of which 78 returned the questionnaire (53.8% female, 46.2% male). In our patient cohort, the vast majority constituting 84.6 percent did not experience pain in the affected upper extremity over the years up to the date of their examination. Most of the patients describing pain had not been microsurgically treated for brachial plexus reconstruction in their neonate period. Merely, 33.3 percent of all OBPI experiencing pain had been microsurgically reconstructed at a median age of 7 months.

CONCLUSIONS

Pain interrogation in patients with OBPI is often overseen during daily clinical routine. Adequate age-appropriate analgesic therapy regimens adapted to the individual are highly recommended. Timely microsurgical brachial plexus reconstruction may result in reduced lifetime pain experiences.

Factors affecting resolution of oculomotor nerve palsy following endovascular embolization of posterior communicating artery aneurysms

PURPOSE

To investigate the effect of endovascular embolization of posterior communicating artery (Pcom) aneurysms on concomitant oculomotor nerve palsy (OMNP) and factors affecting the effect of treatment.

MATERIALS AND METHODS

Patients with the Pcom aneurysms concomitant with OMNP were retrospectively enrolled for endovascular treatment of the aneurysms. All patients had the endovascular management. The clinical effect, degree of OMNP, size of the aneurysm, type of treatment, subarachnoid hemorrhage (SAH), and time from onset to treatment were analyzed on the resolution of OMNP.

RESULTS

Ninety-six patients with 99 Pcom aneurysms were enrolled and treated endovascularly, with the success rate of 100%. Immediately after endovascular treatment, 75 aneurysms (75.75%) got complete occlusion, and 24 (24.24%) nearly complete occlusion. Followed up for 3-18 (mean 8.52±0.56) months, complete resolution of the OMNP was achieved in 63 patients (65.63%), partial resolution in 21 (21.88%), and non-recovery in the other 12 (12.50%). The degree of OMNP at onset, SAH, and time from onset to treatment were significantly (P<0.05) correlated with the resolution of OMNP. Univariate analysis revealed that younger age of the patient, degree of OMNP at onset, presence of subarachnoid hemorrhage, and time from disease onset to treatment were significantly (P<0.05) associated with the recovery of OMNP. Multivariate analysis revealed that the younger age, degree of OMNP at onset, and time from disease onset to treatment were significantly (P<0.05) associated with the recovery of OMNP.

CONCLUSION

Endovascular embolization of Pcom aneurysms concomitant with OMNP can effectively improve the OMNP symptoms, especially for patients with moderate and a shorter history of OMNP. Younger age, degree of oculomotor nerve palsy at onset, and time from onset to treatment may significantly affect recovery of oculomotor nerve palsy.

Vagus Nerve Stimulation Must Occur During Tactile Rehabilitation to Enhance Somatosensory Recovery

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. Here, we systematically varied the timing of VNS relative to tactile rehabilitation to determine the paradigm that yields the greatest degree of somatosensory recovery after peripheral nerve injury (PNI). The medial and ulnar nerves in rats were transected, causing chronic sensory loss. Eight weeks after injury, rats were given a VNS implant followed by four weeks of tactile rehabilitation sessions consisting of repeated mechanical stimuli to the previously denervated forepaw. Rats received VNS before, during, or after tactile rehabilitation. Delivery of VNS during rehabilitative training generates robust, significant recovery compared to rehabilitative training without stimulation (56 ± 14% improvement over sham stimulation). A matched amount of VNS before training, immediately after training, or two hours after training is significantly less effective than VNS during rehabilitative training and fails to improve recovery compared to rehabilitative training alone (5 ± 10%, 4 ± 11%, and -7 ± 22% improvement over sham stimulation, respectively). These findings indicate that concurrent delivery of VNS during rehabilitative training is most effective and illustrate the importance of considering stimulation timing for clinical implementation of VNS therapy.

Touch localization after nerve repair in the hand: insights from a new measurement tool

Errors of touch localization after hand nerve injuries are common, and their measurement is important for evaluating functional recovery. Available empirical accounts have significant methodological limitations, however, and a quantitatively rigorous and detailed description of touch localization in nerve injury is lacking. Here, we develop a new method of measuring touch localization and evaluate its value for use in nerve injury. Eighteen patients with transection injuries to the median/ulnar nerves and 33 healthy controls were examined. The hand was blocked from the participant's view and points were marked on the volar surface using an ultraviolet (UV) pen. These points served as targets for touch stimulation. Two photographs were taken, one with and one without UV lighting, rendering targets seen and unseen, respectively. The experimenter used the photograph with visible targets to register their locations, and participants reported the felt position of each stimulation on the photograph with unseen targets. The error of localization and its directional components were measured, separate from misreferrals-errors made across digits, or from a digit to the palm. Nerve injury was found to significantly increase the error of localization. These effects were specific to the territory of the repaired nerve and showed considerable variability at the individual level, with some patients showing no evidence of impairment. A few patients also made abnormally high numbers of misreferrals, and the pattern of misreferrals in patients differed from that observed in healthy controls.NEW & NOTEWORTHY We provide a more rigorous and comprehensive account of touch localization in nerve injury than previously available. Our results show that touch localization is significantly impaired following median/ulnar nerve transection injuries and that these impairments are specific to the territory of the repaired nerve(s), vary considerably between patients, and can involve frequent errors spanning between digits.

Role of ultrasonography for evaluation of nerve recovery in repaired median nerve lacerations

This study aimed to investigate whether ultrasonographic inspection of the repair site of median nerve lacerations may provide useful evidence about the functional outcome in the affected hand. Forty-three patients with complete transection of the median nerve at the distal forearm were examined at a median of 40.9 months after operation by detailed ultrasonographic imaging and clinical assessment of the affected hand by the Michigan Hand Questionnaire and Rosén-Lundborg Protocol to investigate the quality of nerve healing. The continuity of individual nerve fascicles was assessed and the cross-sectional area of the enlarged nerve at the repair site was measured and compared with the contralateral median nerve at the same level. An enlargement ratio for the repair site of each nerve was calculated and compared with the numeric results obtained from the two clinical tests. A statistically significant reverse correlation was observed between nerve enlargement and the functional results of the repaired nerve.Level of evidence: IV.

Altered Neural Pathways and Related Brain Remodeling: A Rat Study Using Different Nerve Reconstructions

BACKGROUND

Function recovery is related to cortical plasticity. The brain remodeling patterns induced by alterations in peripheral nerve pathways with different nerve reconstructions are unknown.

OBJECTIVE

To explore brain remodeling patterns related to alterations in peripheral neural pathways after different nerve reconstruction surgeries.

METHODS

Twenty-four female Sprague-Dawley rats underwent complete left brachial plexus nerve transection, together with the following interventions: no nerve repair (n = 8), grafted nerve repair (n = 8), and phrenic nerve transfer (n = 8). Resting-state functional MR images of brain were acquired at the end of seventh month postsurgery. Amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), and functional connectivity (FC) were compared among 3 groups. Behavioral observation and electromyography assessed nerve regeneration.

RESULTS

Compared with brachial plexus injury group, ALFF and ReHo of left entorhinal cortex decreased in nerve repair and nerve transfer groups. The nerve transfer group showed increased ALFF and ReHo than nerve repair group in left caudate putamen, right accumbens nucleus shell (AcbSh), and right somatosensory cortex. The FC between right somatosensory cortex and bilateral piriform cortices and bilateral somatosensory cortices increased in nerve repair group than brachial plexus injury and nerve transfer groups. The nerve transfer group showed increased FC between right somatosensory cortex and areas including left corpus callosum, left retrosplenial cortex, right parietal association cortex, and right dorsolateral thalamus than nerve repair group.

CONCLUSION

Entorhinal cortex is a key brain area in recovery of limb function after nerve reconstruction. Nerve transfer related brain remodeling mainly involved contralateral sensorimotor areas, facilitating directional "shifting" of motor representation.

Reversal of neuropathic pain is associated with corticostriatal functional reorganization after nerve repair in the spared nerve injury model

ABSTRACT

Following surgical repair after peripheral nerve injury, neuropathic pain diminishes in most patients but can persist in a small proportion of cases, the mechanism of which remains poorly understood. Based on the spared nerve injury (SNI), we developed a rat nerve repair (NR) model, where a delayed reconstruction of the SNI-injured nerves resulted in alleviating chronic pain-like behavior only in a subpopulation of rats. Multiple behavioral measures were assayed over 11-week presurgery and postsurgery periods (tactile allodynia, pain prick responses, sucrose preference, motor coordination, and cold allodynia) in SNI (n = 10), sham (n = 8), and NR (n = 12) rats. All rats also underwent resting-state functional magnetic resonance imaging under anesthesia at multiple time points postsurgery, and at 10 weeks, histology and retrograde labeling were used to calculate peripheral reinnervation. Behavioral measures indicated that at approximately 5 weeks postsurgery, the NR group separated to pain persisting (NR persisting, n = 5) and recovering (NR recovering, n = 7) groups. Counts of afferent nerves and dorsal root ganglion cells were not different between NR groups. Therefore, NR group differences could not be explained by peripheral reorganization. By contrast, large brain functional connectivity differences were observed between NR groups, where corticolimbic reorganization paralleled with pain recovery (repeated-measures analysis of variance, false discovery rate, P < 0.05), and functional connectivity between accumbens and medial frontal cortex was related both to tactile allodynia (nociception) and to sucrose preference (anhedonia) in the NR group. Our study highlights the importance of brain circuitry in the reversal of neuropathic pain as a natural pain-relieving mechanism. Further studies regarding the therapeutic potentials of these processes are warranted.

Factors affecting resolution of oculomotor nerve palsy following endovascular embolization of posterior communicating artery aneurysms

PURPOSE

To investigate the effect of endovascular embolization of posterior communicating artery (Pcom) aneurysms on concomitant oculomotor nerve palsy (OMNP) and factors affecting the effect of treatment.

MATERIALS AND METHODS

Patients with the Pcom aneurysms concomitant with OMNP were retrospectively enrolled for endovascular treatment of the aneurysms. All patients had the endovascular management. The clinical effect, degree of OMNP, size of the aneurysm, type of treatment, subarachnoid hemorrhage (SAH), and time from onset to treatment were analyzed on the resolution of OMNP.

RESULTS

Ninety-six patients with 99 Pcom aneurysms were enrolled and treated endovascularly, with the success rate of 100%. Immediately after endovascular treatment, 75 aneurysms (75.75%) got complete occlusion, and 24 (24.24%) nearly complete occlusion. Followed up for 3-18 (mean 8.52±0.56) months, complete resolution of the OMNP was achieved in 63 patients (65.63%), partial resolution in 21 (21.88%), and non-recovery in the other 12 (12.50%). The degree of OMNP at onset, SAH, and time from onset to treatment were significantly (P<0.05) correlated with the resolution of OMNP. Univariate analysis revealed that younger age of the patient, degree of OMNP at onset, presence of subarachnoid hemorrhage, and time from disease onset to treatment were significantly (P<0.05) associated with the recovery of OMNP. Multivariate analysis revealed that the younger age, degree of OMNP at onset, and time from disease onset to treatment were significantly (P<0.05) associated with the recovery of OMNP.

CONCLUSION

Endovascular embolization of Pcom aneurysms concomitant with OMNP can effectively improve the OMNP symptoms, especially for patients with moderate and a shorter history of OMNP. Younger age, degree of oculomotor nerve palsy at onset, and time from onset to treatment may significantly affect recovery of oculomotor nerve palsy.

Strategies to Improve Cross-Face Nerve Grafting in Facial Paralysis

Cross-face nerve grafting enables the reanimation of the contralateral hemiface in unilateral facial palsy and may recover a spontaneous smile. This chapter discusses various clinically applicable strategies to increase the chances for good functional outcomes by maintaining the viability of the neural pathway and target muscle, increasing the number of reinnervating nerve fibers and selecting functionally compatible donor nerve branches. Adopting those strategies may help to further improve patient outcomes in facial reanimation surgery.

The effects of sensory re-education on hand function recovery after peripheral nerve repair: A systematic review

BACKGROUND

Peripheral nerve injury can result in both sensory and motor deficits, and these impairments can last for a long period after nerve repair.

OBJECTIVE

To systematically review the effects of sensory re-education (SR) on facilitating hand function recovery after peripheral nerve repair.

METHODS

This systematic review was limited to articles published from 1970 to 20 December 2020. Electronic searching was performed in CINAHL, Embase, PubMed, Web of Science, and Medline databases to include trials investigating the effects of SR training on hand function recovery after peripheral nerve repair and included only those studies with controlled comparisons.

RESULTS

Sixteen articles were included in final data synthesis. We found that only four studies could be rated as having good quality and noted obvious methodological limitations in the remaining studies. The current evidence showed that early SR with mirror visual feedback and the combinational use of classic SR and topical temporary anesthetic seemed to have long- and short-term effects, respectively on improving the sensibility and reducing the disabilities of the hand. The evidence to support the effects of conventional classical SR on improving hand functions was not strong.

CONCLUSIONS

Further well-designed trials are needed to evaluate the effects of different SR techniques on hand function after nerve repair over short- and long-term periods.

Surgically Treated Pediatric Hand and Fingers Palmar Wounds Caused by Metal Fences: Analysis Over a 5-Year Period

BACKGROUND

Hand wounds are frequent in children (31% of hand injuries) and one possible mechanism responsible for profound laceration is metal fences while climbing. These injuries usually require a surgical look to explore soft-tissue damages, but the literature is poor regarding surgical findings and outcomes after this kind of traumatism. The aim of the study was therefore to report a consecutive series of hand and finger wounds caused by metal fences in children, focusing on surgical findings and potential complications.

METHODS

All consecutive hand or finger deep wounds caused by metal fences treated between January 2013 and December 2018 were retrospectively reviewed. Inclusion criteria were age below 18 years and a minimum follow-up of 2 years. Complications and surgical revisions were analyzed.

RESULTS

A total of 1265 patients were operated for hand or finger deep wounds during the study period, among which 74 were caused by metal fences. The mean age at surgery was 11.3±0.4 years, and the majority of patients were men (80%). Associated injuries were found in 55.4% of the patients including nerves (n=29) or tendons sections/disinsertion (n=6), and sheath (n=16) and pulleys (n=6) tearing. At a mean follow-up of 2.6±0.2 years, 12% of the patients required revision surgery for an irreducible flexion contracture secondary to a contractile scar and consisted of complete scar excision and zigzag flap. Additional tenoarthrolysis was required during the procedure, for 6 patients because of a persisting flexion contracture after excision.

CONCLUSIONS

Metal fences surgical palmar wounds in children are impressive lesions by their extended skin damages. Serious associated lesions (collateral pedicle or flexor tendons) were found in 1 case of 3. However, these injuries are not benign and should be carefully monitored clinically during the first postoperative month to look for potential contractile scars that can require revision.

LEVEL OF EVIDENCE

Level IV-retrospective cohort study.

Surgical management of pediatric patients with peripheral nerve and plexus lesions caused by stray bullets

PURPOSE

Children and adolescents are frequent victims of gunshot wounds (GSW), either by direct intent or accidentaly. Lesions caused by stray bullets represent a specific type of accidental GSW and are usually associated with urban violence or aerial firing. We thereby present a series of surgically treated pediatric patients with peripheral nerve and brachial plexus lesions caused by stray bullets, referring to their clinical presentation, surgical procedures, and outcomes.

METHODS

Retrospective study of a series of seven pediatric patients treated from 2012 to 2019 for nerve and/or plexus lesions caused by stray bullets at the Peripheral Nerve Unit of the Division of Neurosurgery of Gaffrée e Guinle University Hospital (HUGG). We used the Visual Analog Scale (VAS) to evaluate pain distress and the British Medical Research Council grading system (BMRC) to assess muscle strength.

RESULTS

Patients' ages ranged from 6 to 17 years old (median of 16), and two were female. All presented preoperatively with intense pain, with a median VAS of 9 (range 7 to 10), and six also had neurological deficits. External neurolysis was conducted in all cases, whereas reconstruction with grafts was needed in four patients. All experienced improvement of pain, and those with motor deficits also experienced some level of recovery.

CONCLUSION

Pediatric patients who endure lesions by stray bullets appear to present with debilitating pain, and often with motor deficits. Multidisciplinary management comprising of surgical treatment and physical and occupational therapy may ameliorate symptoms and improve quality of life, as young patients usually fare better after surgery.

Time heals all wounds - Outcomes of deep palmar wrist injuries may improve long after reinnervation

Despite the clinical importance of deep wrist injuries (DWIs), data on the timeframe of possible improvements in hand function are scarce. We tested the hypotheses that a) the length of follow-up is positively correlated with the outcome, and b) this correlation is tempered by nerve involvement. All patients admitted to the Clinic of Plastic Surgery with an acute DWI between 2008 and 2016 were contacted for a follow-up examination including two-point discrimination, range of motion, grip, and pinch strength, as well as DASH and MMWS questionnaires and employment status. Possible confounders such as age, handedness, and intentionality of the injury (accidental or suicidal) were assessed and controlled for statistically. Fifty-three patients were reviewed (74% male and 26% female, 86% right-handed, 70% accidental injuries, mean age at injury 42.0 ± 17.1 years), an average of 4.3 ± 2.9 years after their injury. In patients with a nerve injury, length of follow-up had significant effects on two-point discrimination, grip and pinch strength, self-reported symptom severity and impairment. Contrary to conventional knowledge, the clinical outcome of DWIs may improve beyond 3 years when there is nerve involvement. This important prognostic finding has far-reaching implications for both clinicians (e.g., asked to give their medical opinion) and patients (e.g., considering re-training after a DWI).

Impaired Limb Functional Outcome of Peripheral Nerve Regeneration Is Marked by Incomplete Recovery of Paw Muscle Atrophy and Brain Functional Connectivity in a Rat Forearm Nerve Repair Model

Skilled sensorimotor deficit is an unsolved problem of peripheral nerve injury (PNI) led by limb trauma or malignancies, despite the improvements in surgical techniques of peripheral nerve anastomosis. It is now accepted that successful functional recovery of PNI relies tremendously on the multilevel neural plasticity from the muscle to the brain. However, animal models that recapitulate these processes are still lacking. In this report, we developed a rat model of PNI to longitudinally assess peripheral muscle reinnervation and brain functional reorganization using noninvasive imaging technology. Based on such model, we compared the longitudinal changes of the rat forepaw intrinsic muscle volume and the seed-based functional connectivity of the sensorimotor cortex after nerve repair. We found that the improvement of skilled limb function and the recovery of paw intrinsic muscle following nerve regeneration are incomplete, which correlated with the functional connectivity between the primary motor cortex and dorsal striatum. Our results were highly relevant to the clinical observations and provided a framework for future investigations that aim to study the peripheral central sensorimotor circuitry underlying skilled limb function recovery after PNI.

Secondary release of the peripheral nerve with autologous fat derivates benefits for functional and sensory recovery

The reconstruction of nerve continuity after traumatic nerve injury is the gold standard in hand surgery. Immediate, tension-free, end-to-end nerve suture ensures the best prognosis. The recovery is mostly promising; however, in a few cases, insufficient outcomes in motor or sensory function are observed. Intra- and extra-fascicular scarring accompanies the nerve regeneration process and limits final outcomes. Secondary nerve release in those cases is recommended. Unfortunately, scarring recurrence cannot be eliminated after secondary revision and neurolysis. The supportive influences of mesenchymal stem cells in the process of nerve regeneration were observed in many preclinical studies. However, a limited number of studies in humans have analyzed the clinical usage of mesenchymal stem cells in peripheral nerve reconstruction and revisions. The objective of this study was to evaluate the effects of undifferentiated adipose-derived stromal/stem cell injection during a last-chance surgery (neurolysis, nerve release) on a previously reconstructed nerve. Three patients (one female, two males; mean age 59 ± 4.5 years at the time of injury), who experienced failure of reconstructions of median and ulnar nerves, were included in this study. During the revision surgery, nerve fascicles were released, and adipose-derived stromal/stem cells were administered through microinjections along the fascicles and around the adjacent tissues after external neurolysis. During 36 months of follow-up, patients noticed gradual signs of sensory and in consequence functional recovery. No adverse effects were observed. Simultaneous nerve release with adipose-derived stromal/stem cells support is a promising method in patients who need secondary nerve release after nerve reconstruction. This method can constitute an alternative procedure in patients experiencing recovery failure and allow improvement in cases of limited nerve regeneration. The study protocol was approved by the Institutional Review Board (IRB) at the Centre of Postgraduate Medical Education (No. 62/PB/2016) on September 14, 2016.

Long-Term Outcomes following Pediatric Peripheral Nerve Injury Repair

Introduction  Peripheral nerve injuries in children are uncommon and can be challenging to diagnose. There is a paucity of data on long-term sensorimotor and functional outcomes following surgical repair. We present a 12-year retrospective analysis of pediatric peripheral nerve repair with long-term functional outcomes. Materials and Methods  We performed a retrospective analysis of pediatric patients with peripheral nerve injury requiring surgical repair. Clinical records were analyzed for procedure type, time to surgery, mechanism of injury, postoperative recovery, and complications. Results  A total of 108 patients were identified and 87 patients were included. Out of 87 patients, 83 (95.4%) had partial or complete sensorimotor recovery at final follow-up and 4 did not improve. Minor complications occurred in 10.3% of patients, all resolved with conservative management. Mechanisms of injury were predominantly lacerations with sharp objects or crush injuries. Age at time of injury was inversely correlated with sensorimotor recovery, and time to surgical repair was not. Conclusion  Surgical repair with long-term hand therapy results in excellent functional outcomes following pediatric peripheral nerve injury. A low threshold for exploration and repair should be used in instances of diagnostic uncertainty. Timing of surgical repair is dependent on a patient's clinical presentation; however, repair within 48 hours is sufficient for optimal sensorimotor recovery.

Restoration of Somatosensory Function by Pairing Vagus Nerve Stimulation with Tactile Rehabilitation

OBJECTIVE

Sensory dysfunction is a common consequence of many forms of neurological injury, including stroke and nerve damage. Rehabilitative paradigms that incorporate sensory retraining can provide modest benefits, but the majority of patients are left with lasting sensory loss. We have developed a novel strategy that uses closed-loop vagus nerve stimulation (VNS) paired with tactile rehabilitation to enhance synaptic plasticity and facilitate recovery of sensory function.

METHODS

A clinical case report provides initial evidence that a similar implementation of closed-loop VNS paired with a tactile rehabilitation regimen could improve recovery of somatosensory function. Here, we sought to build on these promising initial clinical data and rigorously evaluate the ability of VNS paired with tactile rehabilitation to improve recovery in an animal model of chronic sensory loss. The study design, including planned sample size, assessments, and statistical comparisons, was preregistered prior to beginning data collection (https://osf.io/xsnj5/).

RESULTS

VNS paired with tactile rehabilitation resulted in a significant and nearly complete recovery of mechanosensory withdrawal thresholds. Equivalent tactile rehabilitation without VNS failed to improve sensory function. This VNS-dependent restoration of sensory thresholds was maintained for several months after the cessation of stimulation, illustrating long-term benefits. Moreover, VNS paired with tactile rehabilitation resulted in significant generalized improvements in other measures of sensorimotor forepaw function.

INTERPRETATION

Given the safety and tolerability of VNS therapy, these findings suggest that incorporating VNS paired with sensory retraining into rehabilitative regimens may represent a fundamentally new method to increase recovery of sensory function after neurological injury. ANN NEUROL 2020;87:194-205.

Similar 2-point discrimination and stereognosia but better locognosia at long term with an independent home-based sensory reeducation program vs no reeducation after low-median nerve transection and repair

STUDY DESIGN

Prospective controlled study.

INTRODUCTION

Previous studies evaluated the effectiveness of sensory reeducation (SR) after peripheral nerve injury and repair. However, evidence for long-term clinical usefulness of SR is inconclusive.

PURPOSE OF THE STUDY

The purpose of this study is to compare the sensory results of patients with low-median nerve complete transection and microsurgical repair, with and without SR at long term.

METHODS

We prospectively studied 52 consecutive patients (mean age, 36 years; range, 20-47 years) with low-median nerve complete transection and microsurgical repair. When reinnervation was considered complete with perception of vibration with a 256-cycles per second tuning fork (mean, 3.5 months after nerve injury and repair), the patients were sequentially allocated (into 2 groups [group SR, 26 patients, SR; group R, 26 patients, reassured on recovery without SR). SR was conducted in a standardized fashion, in 2 stages, as an independent home-based program: the first stage was initiated when reinnervation was considered complete, and included instruction in home exercises to identify familiar objects and papers of different roughness, and localization of light touch (eyes open and closed); the second stage was initiated when the patients experienced normal static and moving 2-point discrimination (2PD) at the index fingertip of injured hand, and included instruction in home exercises for stereognosia, supplementary exercises for localization of light touch, and identification of small objects (eyes open and closed). Exercises were prescribed for 5-10 minutes, 4 times per day. At 1.5, 3, and 6 years after nerve injury and repair, we evaluated the static and moving 2PD, stereognosia with the Moberg's pick-up test, and locognosia with the modified Marsh test. Comparison between groups and time points was done with the nonparametric analysis of variance (Kruskal-Wallis analysis of variance).

RESULTS

Static and moving 2PD and stereognosia were not significantly different between groups at any study period. Locognosia was significantly better at 1.5 and 3 years in group SR; locognosia was excellent in 17 patients of group SR vs 5 patients of group R at 1.5-year follow-up and in 14 patients of group SR vs 5 patients of group R at 3-year follow-up. Locognosia was not different between the study groups at 6-year follow-up.

CONCLUSION

A 2-stage home program of SR improved locognosia at 1.5 and 3 years after low-median nerve complete transection and repair without significant differences in other modalities or the 6-year follow-up of a small subsample.

Quantitative assessment of cortical somatosensory digit representations after median and ulnar nerve injury in rats

Incomplete recovery of sensory function is common after peripheral nerve injury (PNI). Despite reinnervation following injury, disorganized cortical representations persist and may contribute to functional deficits. There is a dearth of literature characterizing cortical responses after PNI in rodent models. Here we develop a quantitative electrophysiological method for mapping forepaw digit responses in primary somatosensory cortex (S1) of rats. We tested the hypothesis that PNI in the forelimb would generate significant, long lasting sensory deficits, and corresponding disorganization in S1. Rats underwent a transection of the proximal segment of the median and ulnar nerves in the forelimb followed by tubular repair. 4-12 months after nerve injury, we tested mechanosensory withdrawal thresholds and mapped S1 responses to mechanical stimulation of the digits. PNI produces persistent elevation of mechanical withdrawal thresholds, consistent with an impairment in sensory function. Assessment of cortical neurophysiology reveals a substantial disorganization of S1 somatotopy. Additionally, we document degraded timing and digit specificity of cortical responses. This quantitative measurement of long-term changes in S1 digit representations after forelimb nerve injury in rodents provides a framework for further studies focused on the development of therapeutic strategies to restore cortical and sensory function.

Sensory Outcome in Children Following Microsurgery for Brachial Plexus Birth Injury

PURPOSE

Studies are limited on sensory outcome in children with brachial plexus birth injury (BPBI). The purpose of this research was to evaluate the sensory function of the hand in children with BPBI who had microsurgical reconstruction of the brachial plexus.

METHODS

The sensory thresholds of children with upper and total plexus injury were evaluated with the Weinstein Enhanced Sensory Test and a test of stereognosis.

RESULTS

A total of 63 children participated (aged 10.92 ± 3.29 years), 24 (38%) of whom had abnormal sensory thresholds in the affected hand. Only 4 children had loss of protective sensation or higher thresholds. These 4 measurements were all identified in the territory of the superficial branch of the radial nerve. Twelve children with upper plexus (43%) and 12 (34%) with total plexus injury had sensory impairment in the affected hand. These proportions were not statistically different. Of all children evaluated, 18 (29%) had a lower stereognosis score in the affected hand compared with the unaffected hand. The proportions of children with impairment in stereognosis in the upper plexus group (n = 5; 18%) versus the total plexus group (n = 13; 37%) were not statistically different. Age at the time of assessment, sex, upper versus total plexus injury, number of root avulsions, subjective report of altered sensation, and Faces Pain Scale-Revised score were not related to sensory impairment in the affected hand.

CONCLUSIONS

Sensory recovery in BPBI after microsurgical reconstruction in children with total plexus injury who had reconstruction of the lower trunk had the potential to achieve sensory recovery similar to their upper plexus counterparts. A large proportion of children achieve normal sensory outcome, and those who had deficits had mild impairments.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Peripheral nerve injuries in the pediatric population: a review of the literature. Part I: traumatic nerve injuries

OBJECTIVE

This article reviews the clinical results that can be obtained after repair of a traumatic peripheral nerve injury in the pediatric population.

METHODS

A systematic review of the published literature has been made.

RESULTS

Functional outcome after major nerve injuries is sometimes disappointing in adults. However, children have been reported to experience much better functional results after nerve repair than adults. Moreover, recovery generally is faster in children. The superior capacity of children's central nervous system to adapt to external or internal environmental changes (neural plasticity) and the shorter recovery distance from the axon repair site to the target muscle are claimed to be crucial determinants of their favorable outcomes. Moreover, even in the pediatric population, it has been demonstrated that functional results are better the younger the patient is, including better clinical results in those injured in early childhood (< 6 years old) than in those injured in adolescence. Other favorable prognostic factors include the type of nerve injury (with complete transections doing less well than crush injuries) and the timing of surgery (with better outcomes after early repairs).

CONCLUSIONS

All efforts should be done to repair in a timely and adequate fashion traumatic peripheral nerve injuries in children, as the results are good.

The plasticity of the corticospinal tract in children with obstetric brachial plexus palsy after Botulinum Toxin A treatment

Botulinum neurotoxin A (BTX-A) intervention has long-term benefits for children with obstetric brachial plexus palsy (OBPP). Although cortical plasticity has been widely studied, plasticity in white matter has not received as much attention. Here, six children with OBPP underwent functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) before and 6 months after BTX-A treatment. Surface electromyography (EMG) was recorded. The aim was to investigate changes in the corticospinal tract (CST) as an example longitudinal observation of white matter plasticity. Deterministic fiber tracking with a Fiber Assignment by Continuous Tracking algorithm was used to reconstruct the CST. Fiber tracts passing through a region of interest (ROI) in the posterior limb of the internal capsule and a target ROI in the upper-limb representation of M1 (defined by task-related fMRI) were selected as the CST. Motor performances were improved while EMG showed no significant difference 6 months after the treatment. We observed a significant increase in mean fractional anisotropy and a significant decrease in fiber number after treatment. We analyzed the correlations between DTI metrics and clinical motor assessments. Although the correlation results were not statistically significant, they support the notion that BTX-A treatment causes white matter plasticity and has a positive long-term outcome. Peripheral deafferentation may lead to altered information flow, resulting in the positive adaptation of white matter. This study provides novel insight into cerebral plasticity following peripheral nerve regeneration and indicates that a combination of relatively non-invasive therapies can accelerate plasticity of sensorimotor circuits and promote functional recovery in OBPP.

A review of invasive and non-invasive sensory feedback in upper limb prostheses

INTRODUCTION

The constant challenge to restore sensory feedback in prosthetic hands has provided several research solutions, but virtually none has reached clinical fruition. A prosthetic hand with sensory feedback that closely imitates an intact hand and provides a natural feeling may induce the prosthetic hand to be included in the body image and also reinforces the control of the prosthesis. Areas covered: This review presents non-invasive sensory feedback systems such as mechanotactile, vibrotactile, electrotactile and combinational systems which combine the modalities; multi-haptic feedback. Invasive sensory feedback has been tried less, because of the inherent risk, but it has successfully shown to restore some afferent channels. In this review, invasive methods are also discussed, both extraneural and intraneural electrodes, such as cuff electrodes and transverse intrafascicular multichannel electrodes. The focus of the review is on non-invasive methods of providing sensory feedback to upper-limb amputees. Expert commentary: Invoking embodiment has shown to be of importance for the control of prosthesis and acceptance by the prosthetic wearers. It is a challenge to provide conscious feedback to cover the lost sensibility of a hand, not be overwhelming and confusing for the user, and to integrate technology within the constraint of a wearable prosthesis.

Bioabsorbable nerve conduits coated with induced pluripotent stem cell-derived neurospheres enhance axonal regeneration in sciatic nerve defects in aged mice

Aging influences peripheral nerve regeneration. Nevertheless, most basic research of bioabsorbable nerve conduits including commercial products have been performed in very young animals. Results from these studies may not provide information about axonal regeneration in aged tissue, because young nerve tissue holds sufficient endogenous potential for axonal regeneration. The clinical target age for nerve conduit application is most likely going to increase with a rapidly growing elderly population. In the present study, we examined axonal regeneration after sciatic nerve defects in aged and young mice. 5-mm sciatic nerve defects in young (6 weeks old) and aged (92 weeks old) mice were reconstructed using nerve conduits (composed of a poly lactide and caprolactone) or autografts. In addition, in aged mice, sciatic nerve defects were reconstructed using nerve conduits coated with mouse induced pluripotent stem cell (iPSc)-derived neurospheres. Using electrophysiological and histological techniques, we demonstrated axonal regeneration was significantly less effective in aged than in young mice both for nerve conduits and for nerve autografts. However, despite the low regenerative capacity of the peripheral nerve in aged mice, axonal regeneration significantly increased when nerve conduits coated with iPSc-derived neurospheres, rather than nerve conduits alone, were used. The present study shows that aging negatively affects peripheral nerve regeneration based on nerve conduits in mice. However, axonal regeneration using nerve conduits was improved when supportive iPSc-derived neurospheres were added in the aged mice. We propose that tissue-engineered bioabsorbable nerve conduits in combination with iPSc-derived neurospheres hold therapeutic potential both in young and elderly patients. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1752-1758, 2018.

Key considerations in designing a somatosensory neuroprosthesis

In recent years, a consensus has emerged that somatosensory feedback needs to be provided for upper limb neuroprostheses to be useful. An increasingly promising approach to sensory restoration is to electrically stimulate neurons along the somatosensory neuraxis to convey information about the state of the prosthetic limb and about contact with objects. To date, efforts toward artificial sensory feedback have consisted mainly of demonstrating that some sensory information could be conveyed using a small number of stimulation patterns, generally delivered through single electrodes. However impressive these achievements are, results from different studies are hard to compare, as each research team implements different stimulation patterns and tests the elicited sensations differently. A critical question is whether different stimulation strategies will generalize from contrived laboratory settings to activities of daily living. Here, we lay out some key specifications that an artificial somatosensory channel should meet, discuss how different approaches should be evaluated, and caution about looming challenges that the field of sensory restoration will face.

Occupation-based intervention versus rote exercise in modified constraint-induced movement therapy for patients with median and ulnar nerve injuries: a randomized controlled trial

Objective:

To investigate effect of practice type during modified constraint-induced movement therapy on hand function in patients with chronic median and ulnar nerve injuries.

Design:

A prospective, single-blinded, randomized controlled clinical trial.

Setting:

Participants’ private home.

Subjects:

A convenience sample of 36 outpatient participants allocated randomly to three equal groups.

Interventions:

Intervention groups underwent 3-hour intensive training of affected hand each day, 3-day a week, 4-week in association with immobilisation of healthy hand: occupation-based group practiced meaningful occupations while rote exercise-based group performed rote exercises during constraint-induced movement therapy. Control group performed different activities with affected hand for 1.5-hour each day during 4-week without restriction of healthy hand.

Main measures:

A blinded assessor tested Canadian occupational performance measure, box and block, Static two-point discrimination, disabilities of arm, shoulder, hand questionnaire, and self-assessment manikin in a random order across sessions 3-time as baseline (pre-test), after 4-week intervention (post-test), and 1-month after intervention period (follow up).

Results:

Scores significantly changed in intervention groups compared to control. Despite significantly more improvement in occupation-based than rote exercise-based group in subjective measures at post-test and follow up (Canadian occupational performance measure: mean change 4.7 vs. 2.1 for performance, P< 0.001 and mean change 5.3 vs. 2.6 for satisfaction, P< 0.001), it was significant just at follow up for box and block and static two-point discrimination.

Conclusions:

Practice content of constraint-induced movement therapy is a critical part of its effectiveness on improving outcomes following peripheral nerve repair in favour of occupation-based intervention in present study.

Sensory Re-education Today and Tomorrow: A Review of Evolving Concepts

Following surgical repair of major nerve trunks there is a rapid functional reorganisation in the brain, characterised by a changed cortical mapping of the hand secondary to incorrect reinnervation of peripheral targets. Sensory re-educational programmes are used in the rehabilitation phase to facilitate and positively influence the re-learning process, which is required to make possible an adaptation to the new synaptic organisation and to improve the recovery of functional sensibility - tactile gnosis. However, the outcome is often disappointing, especially in adults. The design of sensory re-education programmes has not changed for several decades. The purpose of this paper is to review evolving concepts in neuroscience and cognitive science, present a rationale for a modified approach to classic sensory re-education, and suggest new strategies for enhanced sensory re-learning following nerve repair.

Technical Assessment of Connector-Assisted Nerve Repair

PURPOSE

Clinical outcomes of nerve repair have not substantially improved over the last several decades. Although clearly a multifactorial problem, basic principles including proper fascicular alignment are not always realized. The use of short conduits as connectors may enhance nerve alignment by entubulating and directing the approximation of nerve ends.

METHODS

Ten hand surgeons (5 experienced and 5 inexperienced) performed a series of in vitro human cadaver nerve repairs. Three small-diameter (2 mm), 3 medium-diameter (3-4 mm), and 3 large-diameter (5-6 mm) nerves were repaired (under 10× magnification) utilizing each of 3 techniques: suture-only, connector-only (sutures placed through the ends of the connector), and connector-assisted (alignment sutures at the nerve interface plus connector). Three judges (blinded to who performed the repairs) assessed each repair for fascicular alignment based on predetermined qualitative scales.

RESULTS

Across all surgeons, 23 of 30 connector-assisted repairs were judged good or excellent versus 18 of 30 of the suture-only and 13 of 30 of the connector-only repairs. Experienced surgeons in general did better repairs and in particular were more likely to obtain superior alignment for conduit-only repairs (73.3% vs 13.3% good or excellent) and suture-only repairs (73.3% vs 46.7% good or excellent) and were not statistically different for connector-assisted repairs (86.7% vs 66.7% good or excellent) compared with inexperienced surgeons.

CONCLUSIONS

In a cadaver nerve model, there was no significant difference in the technical alignment of conduit-assisted repairs between experienced and inexperienced surgeons whereas inexperienced surgeons were more likely to achieve inadequate alignment with suture-only or conduit-only repairs.

CLINICAL RELEVANCE

Connector-assisted repairs combining suture-approximation and entubulation may improve the technical alignment of nerve repairs performed, especially by less-experienced surgeons.

Sensory re-education after nerve injury of the upper limb: a systematic review

Objective : To systematically review the available evidence for the effectiveness of sensory re-education to improve the sensibility of the hand in patients with a peripheral nerve injury of the upper limb.

Data sources : Studies were identified by an electronic search in the databases MEDLINE, Cumulative Index to Nursing & Allied Health Literature (CINAHL), EMBASE, the Cochrane Library, the Physiotherapy Evidence Database (PEDro), and the database of the Dutch National Institute of Allied Health Professions (Doconline) and by screening the reference lists of relevant articles.

Review methods : Two reviewers selected studies that met the following inclusion criteria: all designs except case reports, adults with impaired sensibility of the hand due to a peripheral nerve injury of the upper limb, and sensibility and functional sensibility as outcome measures. The methodological quality of the included studies was independently assessed by two reviewers. A best-evidence synthesis was performed, based on design, methodological quality and significant findings on outcome measures.

Results : Seven studies, with sample sizes ranging from 11 to 49, were included in the systematic review and appraised for content. Five of these studies were of poor methodological quality. One uncontrolled study (N = 1 3 ) was considered to be of sufficient methodological quality, and one randomized controlled trial ( N = 49) was of high methodological quality. Best-evidence synthesis showed that there is limited evidence for the effectiveness of sensory re-education, provided by a statistically significant improvement in sensibility found in one high-quality randomized controlled trial.

Conclusion : There is a need for further well-defined clinical trials to assess the effectiveness of sensory re-education of patients with impaired sensibility of the hand due to a peripheral nerve injury.

Evaluation of pediatric upper extremity peripheral nerve injuries

INTRODUCTION

The evaluation of motor and sensory function of the upper extremity after a peripheral nerve injury is critical to diagnose the location and extent of nerve injury as well as document functional recovery in children.

PURPOSE

The purpose of this paper is to describe an approach to the evaluation of the pediatric upper extremity peripheral nerve injuries through a critical review of currently used tests of sensory and motor function.

METHODS

Outcome studies on pediatric upper extremity peripheral nerve injuries in the Medline database were reviewed.

RESULTS

The evaluation of the outcome in children less than 10 years of age with an upper extremity peripheral nerve injury includes careful observation of preferred prehension patterns, examination of muscle atrophy and sudomotor function, provocative tests, manual muscle testing and tests of sensory threshold and tactile gnosis.

CONCLUSION

The evaluation of outcome in children with upper extremity peripheral nerve injuries warrants a unique approach.

Normalized activation in the somatosensory cortex 30 years following nerve repair in children: an fMRI study

The clinical outcome following a peripheral nerve injury in the upper extremity is generally better in young children than in teenagers and in adults, but the mechanism behind this difference is unknown. In 28 patients with a complete median nerve injury sustained at the ages of 1-13 years (n = 13) and 14-20 years (n = 15), the cortical activation during tactile finger stimulation of the injured and healthy hands was monitored at a median time since injury of 28 years using functional magnetic resonance imaging (fMRI) at 3 Tesla. The results from the fMRI were compared with the clinical outcome and electroneurography. The cortical activation pattern following sensory stimulation of the median nerve-innervated fingers was dependent on the patient's age at injury. Those injured at a young age (1-13 years) had an activation pattern similar to that of healthy controls. Furthermore, they showed a clinical outcome significantly superior (P = 0.001) to the outcome in subjects injured at a later age; however, electroneurographical parameters did not differ between the groups. In subjects injured at age 14-20 years, a more extended activation of the contralateral hemisphere was seen in general. Interestingly, these patients also displayed changes in the ipsilateral hemisphere where a reduced inhibition of somatosensory areas was seen. This loss of ipsilateral inhibition correlated to increasing age at injury as well as to poor recovery of sensory functions in the hand. In conclusion, cerebral changes in both brain hemispheres may explain differences in clinical outcome following a median nerve injury in childhood or adolescence.

Management and complications of traumatic peripheral nerve injuries

This article provides an overview of the management of traumatic peripheral nerve injuries. It examines the basic pathophysiology of peripheral nerve injuries, along with the clinical presentation, diagnostic work-up, and treatment options and outcomes for the various classifications of traumatic peripheral nerve injuries.

"Sensory Switching" in Elbow Reconstruction

In the treatment of the soft tissue defect of the elbow, flap reconstruction is necessitated in many cases because of thinness of soft tissue at this region. In addition, reacquirement of tactile sensation is desirable because of the anatomical and specific functions of the elbow. Of three cases treated for elbow defects, one was reconstructed with a pedicled island forearm flap containing the lateral cutaneous nerve of the forearm, another was reconstructed with a venoneuro-accompanying artery fasciocutaneous flap (VNAF flap) containing the basilic vein, and the third with the VNAF flap containing the cephalic vein. The three cases demonstrated a sudden change of sensory territory 4 to 6 months after surgery, which was confirmed by touching the reconstructed region with patients' eye-closed: from its original territory to the elbow in a "switching"-like action. Here we describe and discuss the concept of "sensory switching."

Hydrogels as scaffolds and delivery systems to enhance axonal regeneration after injuries

Damage caused to neural tissue by disease or injury frequently produces a discontinuity in the nervous system (NS). Such damage generates diverse alterations that are commonly permanent, due to the limited regeneration capacity of the adult NS, particularly the Central Nervous System (CNS). The cellular reaction to noxious stimulus leads to several events such as the formation of glial and fibrous scars, which inhibit axonal regeneration in both the CNS and the Peripheral Nervous System (PNS). Although in the PNS there is some degree of nerve regeneration, it is common that the growing axons reinnervate incorrect areas, causing mismatches. Providing a permissive substrate for axonal regeneration in combination with delivery systems for the release of molecules, which enhances axonal growth, could increase regeneration and the recovery of functions in the CNS or the PNS. Currently, there are no effective vehicles to supply growth factors or cells to the damaged/diseased NS. Hydrogels are polymers that are biodegradable, biocompatible and have the capacity to deliver a large range of molecules in situ. The inclusion of cultured neural cells into hydrogels forming three-dimensional structures allows the formation of synapses and neuronal survival. There is also evidence showing that hydrogels constitute an amenable substrate for axonal growth of endogenous or grafted cells, overcoming the presence of axonal regeneration inhibitory molecules, in both the CNS and PNS. Recent experiments suggest that hydrogels can carry and deliver several proteins relevant for improving neuronal survival and axonal growth. Although the use of hydrogels is appealing, its effectiveness is still a matter of discussion, and more results are needed to achieve consistent recovery using different parameters. This review also discusses areas of opportunity where hydrogels can be applied, in order to promote axonal regeneration of the NS.

Cortical adaptation staging system: a new and simple staging for result evaluation of functioning free-muscle transplantation for facial reanimation

BACKGROUND

Movement-associated cortical reorganization occurs in patients after functioning free-muscle transplantation (FFMT), which is reinnervated by different neurotizers. Aiming to evaluate the process of recovery of the reinnervated muscle, we defined the cortical reorganization into 5 stages. This staging system has been applied during the past 25 years at our center with great convenience and accessibility.

METHODS

A standardized evaluation method for assessing the recovery after FFMT to reanimate the paralyzed face with at least a 1-year follow-up was applied. The evaluation included the following 5 stages: no movement, dependent movement, independent movement, and spontaneous movement with and without involuntary movement. Reliability of this technique was assessed by 3 examiners, who each evaluated the smiles of 30 unilateral facial paralysis patients 4 times, creating 360 sets of measurements.

RESULTS

The intraclass correlation coefficients for interrater and intrarater reliability exceeded 0.929, which is considered excellent and reliable.

CONCLUSIONS

Chuang's Cortical Adaptation Staging System is simple, quick,and accurate in evaluating patients after FFMT reanimation of the paralyzed face with no additional tools.

Management of ulnar nerve injuries

Injuries to the ulnar nerve result in both sensory and motor deficits within the hand. Functional outcomes following repair of this nerve have not performed as well as outcomes following repair of the median or radial nerves. Advances in imaging modalities may provide earlier means of identifying and diagnosing closed nerve injuries. Early neurorrhaphy of acute nerve injuries provides the best outcome, but consideration should also be given to performing distal motor nerve transfers to preserve hand intrinsic motor function when injuries occur at or above the proximal forearm. This article attempts to summarize the most recent trends within ulnar nerve repair.

Diminished Schwann cell repair responses underlie age-associated impaired axonal regeneration

The regenerative capacity of the peripheral nervous system declines with age. Why this occurs, however, is unknown. We demonstrate that 24-month-old mice exhibit an impairment of functional recovery after nerve injury compared to 2-month-old animals. We find no difference in the intrinsic growth capacity between aged and young sensory neurons in vitro or in their ability to activate growth-associated transcriptional programs after injury. Instead, using age-mismatched nerve transplants in vivo, we show that the extent of functional recovery depends on the age of the nerve graft, and not the age of the host. Molecular interrogation of the sciatic nerve reveals that aged Schwann cells (SCs) fail to rapidly activate a transcriptional repair program after injury. Functionally, aged SCs exhibit impaired dedifferentiation, myelin clearance, and macrophage recruitment. These results suggest that the age-associated decline in axonal regeneration results from diminished Schwann cell plasticity, leading to slower myelin clearance.

Consequences and adaptation in daily life - patients' experiences three decades after a nerve injury sustained in adolescence

Background

To explore the patients’ experiences during the three decades following repair of a nerve injury in the forearm and its consequences for daily life. Strategies that were used to facilitate adaptation were also investigated.

Methods

Fifteen participants with a complete median and/or ulnar nerve injury repaired in the ages from 13–20 years were interviewed using a semi-structured interview guide. The median follow-up time was 31 years (range 23–40). The participants were asked to describe the past and present symptoms of the injured hand, the consequences of the injury for daily life, personal qualities and support from others. In addition, they were asked to describe strategies used to facilitate adaptation. The interviews were subjected to content analysis.

Results

The nerve injury lead to sensory and motor deficits in the injured hand, as well as sensitivity to cold and secondary back problems. Emotional reactions to trauma and symptoms related to post-traumatic stress disorder were described, as well as how they managed to cope with such reactions. There was a noticeable impact on education, leisure, professional or domestic life for some, while others could continue by changing e.g. their performance pattern. The participants’ life roles and relations were also affected. Both emotion- and problem-based strategies were used to manage challenges in daily life.

Conclusions

The present qualitative study can help us to provide the patient with honest and realistic information about what to expect after a nerve injury at forearm level, without eliminating hope. Emotional reactions to trauma should be identified and dealt with. In addition, health-care professionals can promote a variety of coping mechanisms to facilitate daily living for the injured patients.

Major peripheral nerve injuries

Major peripheral nerve injuries in the upper extremities can result in significant morbidity. Understanding the pathophysiology of these injuries aids in the assessment and planning of appropriate treatment. With limited nerve mobilization, tension-free repairs can often be performed using sutures, fibrin glue, or nerve connectors. Acellular allograft and autograft reconstruction are better for bridging any gaps greater than a few millimeters. Adherence to proper principles of nerve repair improves the chances of achieving a favorable result, although in general these injuries portend a guarded prognosis.

Poor electroneurography but excellent hand function 31 years after nerve repair in childhood

Children, in contrast to adults, show an excellent clinical recovery after a peripheral nerve injury, which may be explained by better peripheral nerve regeneration and a superior plasticity in the young brain. Our aim was to study the long-term electrophysiological outcome after nerve repair in children and young adults and to compare it with the clinical outcome. Forty-four patients, injured at an age younger than 21 years, were assessed by electrophysiology (amplitude, conduction velocity and distal motor latency) at a median of 31 years after a complete median or ulnar nerve injury at the level of the forearm. Electrophysiological evaluation showed pathology in all parameters and in all patients, irrespective of age at injury. No significant differences were observed in the electrophysiological results between those injured in childhood, that is, before the age of 12 years, and those injured in adolescence, that is, between 12 and 20 years of age. In contrast, the clinical nerve function was significantly better for those injured in childhood (87% of complete recovery, P=0.002) compared with those injured in adolescence. We conclude that the mechanism behind the superior clinical outcome in children is not located at the periphery, but is explained by cerebral plasticity.

A cross-sectional study of hand sensation in adults with conservatively treated obstetric brachial plexus lesion

AIM

Sensory function is assumed to recover almost completely in obstetric brachial plexus lesion (OBPL), and is reported to recover much better than motor function. However, there is no obvious physiological reason why this should be so. Any persistent problems with sensory innervation might contribute to disability, therefore we aimed to assess sensory dysfunction in adults resulting from OBPL.

METHOD

Adults with conservatively treated OBPL (n=17; 12 females, five males; median age 38y; lesion levels: C5-C6, n=7; C5-C7, n=7; C5-C8, n=2; C5-Th1, n=1) and 19 healthy comparison persons (10 females, nine males; median age 23y) were investigated. Sensory function was measured using Semmes-Weinstein monofilaments, two-point discrimination, object recognition, and a locognosia test.

RESULTS

Scores of the Semmes-Weinstein monofilaments and two-point discrimination, but not object recognition or locognosia, were significantly worse in those with OBPL than in those without OBPL.

INTERPRETATION

There may be systematic abnormalities in sensory function in adults with conservatively treated OBPL. The existence of these impairments and their contribution to functional impairment needs to be acknowledged.

Axillary nerve injury in young adults--an overlooked diagnosis? Early results of nerve reconstruction and nerve transfers

An injury to the axillary nerve from a shoulder trauma can easily be overlooked. Spontaneous functional recovery may occur, but occasionally reconstructive surgery is required. The time frame for nerve reconstruction procedures is from a neurobiological view crucial for a good functional outcome. This study presents a group of operatively and non-operatively treated young adults with axillary nerve injuries caused by motorcycle accidents, where the diagnosis was set late. Ten young men (median age at trauma 13 years, range 9-24) with an axillary nerve injury were diagnosed by examination of shoulder function and electromyography (EMG). The patients had either a nerve reconstruction procedure or were treated conservatively and their recovery was monitored. The axillary nerve was explored and reconstructed at a median of 8 months (range 1-22 months) after trauma in 8/10 patients. Two patients were treated non-operatively. In 4/8 cases, a reconstruction with sural nerve graft was performed and in 1/8 case only exploration of the nerve was made (minor neuroma). In 3/8 cases a radial nerve branch transfer to the axillary nerve was chosen as the procedure. The shoulder was mobilised after 3 weeks with physiotherapy and the patients were monitored regularly. Functional recovery was observed in 9/10 cases (median follow up 11 months, range 7-64) with EMG signs of reinnervation in seven patients. Axillary nerve function should not be overlooked in young patients with a minor shoulder trauma. Nerve reconstruction can successfully recreate function.

Median and ulnar nerve grafting in children

A case series of seven children and adolescents who underwent secondary nerve grafting of median or ulnar nerve is presented. The children were evaluated after a mean follow-up of 7 years, using the Disabilities of Arm Shoulder and Hand (DASH) questionnaire and the Rosen-Lundborg outcome scale. The mean DASH outcome was 14.6 and the mean Rosen-Lundborg score was 2.08. A similar study was conducted for comparison in an adult group, with a mean DASH score of 46.3 and Rosen-Lundborg score of 1.3, indicating superior treatment results in children. The treatment outcome after nerve grafting in children did not match, however, to those obtained in the primary suture group.