Brain plasticity in neonatal brachial plexus palsies: quantification and comparison with adults' brachial plexus injuries.

PURPOSE: To compare two populations of brachial plexus palsies, one neonatal (NBPP) and the other traumatic (NNBPP) who underwent different nerve transfers, using the plasticity grading scale (PGS) for detecting differences in brain plasticity between both groups. METHODS: To be included, all patients had to have undergone a nerve transfer as the unique procedure to recover one lost function. The primary outcome was the PGS score. We also assessed patient compliance to rehabilitation using the rehabilitation quality scale (RQS). Statistical analysis of all variables was performed. A p ≤ 0.050 set as criterion for statistical significance. RESULTS: A total of 153 NNBPP patients and 35 NBPP babies (with 38 nerve transfers) met the inclusion criteria. The mean age at surgery of the NBPP group was 9 months (SD 5.42, range 4 to 23 months). The mean age of NNBPP patients was 22 years (SD 12 years, range 3 to 69). They were operated around sixth months after the trauma. All transfers performed in NBPP patients had a maximum PGS score of 4. This was not the case for the NNBPP population that reached a PGS score of 4 in approximately 20% of the cases. This difference was statistically significant (p < 0.001). The RQS was not significantly different between groups. CONCLUSION: We found that babies with NBPP have a significantly greater capacity for plastic rewiring than adults with NNBPP. The brain in the very young patient can process the changes induced by the peripheral nerve transfer better than in adults.

Optimal timing of needle electromyography to diagnose lesion severity in traumatic radial nerve injury.

INTRODUCTION/AIMS: In patients with traumatic radial nerve injury (RNI), the chance of spontaneous recovery must be balanced against the benefits of early surgical reconstruction. We aimed to explore the time-specific value of needle electromyography (NEMG) to diagnose nerve lesion severity. METHODS: In this retrospective diagnostic accuracy study at Leiden Nerve Center, patients at least 12 years of age with RNI caused by fractures or fracture treatment were included. The sensitivity and specificity of the patients' first NEMG examination were assessed, stratified by the timing after the nerve injury. The absence of motor unit potentials (MUPs) in muscles distal to the nerve lesion was considered a positive test result. Lesion severity was dichotomized to moderate injury (spontaneous Medical Research Council grade ≥3 recovery) or severe injury (poor spontaneous recovery or surgical confirmation of a mainly neurotmetic lesion). RESULTS: Ninety-five patients were included in our study. The sensitivity of NEMG to detect severe RNI was 75.0% (3 of 4) in the fourth, 66.7% (2 of 3) in the fifth, and 66.7% (2 of 3) in the sixth month after the nerve injury. The specificity in the first to the sixth month was 0.0% (0 of 1), 50.0% (2 of 4), 77.3% (17 of 22), 95.5% (21 of 22), 95.8% (23 of 24), and 100.0% (12 of 12), respectively. DISCUSSION: The specificity of NEMG is higher than 95% and therefore clinically relevant from the fourth month after the nerve injury onward. Absence of MUPs at this time can be considered an indication to plan nerve exploration. Moreover, the presence of MUPs on NEMG does not completely exclude the necessity for surgical reconstruction.

Tactile Perception of the Hand in Children With an Upper Neonatal Brachial Plexus Palsy.

OBJECTIVE: To investigate factors that cause impairment of hand function in children with an upper Neonatal Brachial Plexus Palsy (NBPP), we performed an in-depth analysis of tactile hand sensibility, especially the ability to correctly localize a sensory stimulus on their fingers. DESIGN: A cross-sectional investigation of children with NBPP, compared with healthy controls. The thickest Semmes-Weinstein (SW) monofilament was pressed on the radial or ulnar part of each fingertip (10 regions), while a screen prevented seeing the hand. SETTING: Tertiary referral center for nerve lesions in an academic hospital in The Netherlands. The control group was recruited at their school. PARTICIPANTS: Forty-one children with NBPP (mean age 10.0 y) and 25 controls (mean age 9.5 y; N=41). INTERVENTIONS: Not applicable. MAIN OUTCOMES MEASURES: Correct localization of the applied stimuli was evaluated, per region, per finger, and per dermatome with a test score. The affected side of the NBPP group was compared with the non-dominant hand of the controls. RESULTS: The ability to localize stimuli on the tips of the fingers in children with an upper NBPP was significantly diminished in all fingers, except for the little finger, as compared with healthy controls. Mean localization scores were 6.6 (thumb) and 6.3 (index finger) in the NBPP group and 7.6 in both fingers for controls (maximum score possible is 8.0). Localization scores were significant lower in regions attributed to dermatomes C6 (P<.001) and C7 (P=.001), but not to C8 (P=.115). CONCLUSION: Children with an upper NBPP showed a diminished and incorrect ability to localize sensory stimuli to their fingers. This finding is likely 1 of the factors underlying the impairment of hand function and should be addressed with sensory focused therapy.

Molecular Changes in the Dorsal Root Ganglion during the Late Phase of Peripheral Nerve Injury-induced Pain in Rodents: A Systematic Review.

The dorsal root ganglion is widely recognized as a potential target to treat chronic pain. A fundamental understanding of quantitative molecular and genomic changes during the late phase of pain is therefore indispensable. The authors performed a systematic literature review on injury-induced pain in rodent dorsal root ganglions at minimally 3 weeks after injury. So far, slightly more than 300 molecules were quantified on the protein or messenger RNA level, of which about 60 were in more than one study. Only nine individual sequencing studies were performed in which the most up- or downregulated genes varied due to heterogeneity in study design. Neuropeptide Y and galanin were found to be consistently upregulated on both the gene and protein levels. The current knowledge regarding molecular changes in the dorsal root ganglion during the late phase of pain is limited. General conclusions are difficult to draw, making it hard to select specific molecules as a focus for treatment.

What is the Elbow Flexion Strength After Free Functional Gracilis Muscle Transfer for Adult Traumatic Complete Brachial Plexus Injuries?

BACKGROUND: Traumatic brachial plexus injuries (BPIs) in the nerve roots of C5 to T1 lead to the devastating loss of motor and sensory function in the upper extremity. Free functional gracilis muscle transfer (FFMT) is used to reconstruct elbow and shoulder function in adults with traumatic complete BPIs. The question is whether the gains in ROM and functionality for the patient outweigh the risks of such a large intervention to justify this surgery in these patients. QUESTIONS/PURPOSES: (1) After FFMT for adult traumatic complete BPI, what is the functional recovery in terms of elbow flexion, shoulder abduction, and wrist extension (ROM and muscle grade)? (2) Does the choice of distal insertion affect the functional recovery of the elbow, shoulder, and wrist? (3) Does the choice of nerve source affect elbow flexion and shoulder abduction recovery? (4) What factors are associated with less residual disability? (5) What proportion of flaps have necrosis and do not reinnervate? METHODS: We performed a retrospective observational study at Dr. Soetomo General Hospital in Surabaya, Indonesia. A total of 180 patients with traumatic BPIs were treated with FFMT between 2010 and 2020, performed by a senior orthopaedic hand surgeon with 14 years of experience in FFMT. We included patients with traumatic complete C5 to T1 BPIs who underwent a gracilis FFMT procedure. Indications were total avulsion injuries and delayed presentation (>6 months after trauma) or after failed primary nerve transfers (>12 months). Patients with less than 12 months of follow-up were excluded, leaving 130 patients eligible for this study. The median postoperative follow-up period was 47 months (interquartile range [IQR] 33 to 66 months). Most were men (86%; 112 of 130) who had motorcycle collisions (96%; 125 patients) and a median age of 23 years (IQR 19 to 34 years). Orthopaedic surgeons and residents measured joint function at the elbow (flexion), shoulder (abduction), and wrist (extension) in terms of British Medical Research Council (MRC) muscle strength scores and active ROM. A univariate analysis of variance test was used to evaluate these outcomes in terms of differences in distal attachment to the extensor carpi radialis brevis (ECRB), extensor digitorum communis and extensor pollicis longus (EDC/EPL), the flexor digitorum profundus and flexor pollicis longus (FDP/FPL), and the choice of a phrenic, accessory, or intercostal nerve source. We measured postoperative function with the DASH score and pain at rest with the VAS score. A multivariate linear regression analysis was performed to investigate what patient and injury factors were associated with less disability. Complications such as flap necrosis, innervation problems, infections, and reoperations were evaluated. RESULTS: The median elbow flexion muscle strength was 3 (IQR 3 to 4) and active ROM was 88° ± 46°. The median shoulder abduction grade was 3 (IQR 2 to 4) and active ROM was 62° ± 42°. However, the choice of distal insertion was not associated with differences in the median wrist extension strength (ECRB: 2 [IQR 0 to 3], EDC/EPL: 2 [IQR 0 to 3], FDP/FPL: 1 [IQR 0 to 2]; p = 0.44) or in ROM (ECRB: 21° ± 19°, EDC/EPL: 21° ± 14°, FDP/FPL: 13° ± 15°; p = 0.69). Furthermore, the choice of nerve source did not affect the mean ROM for elbow flexion (phrenic nerve: 87° ± 46°; accessory nerve: 106° ± 49°; intercostal nerves: 103° ± 50°; p = 0.55). No associations were found with less disability (lower DASH scores): young age (coefficient = 0.28; 95% CI -0.22 to 0.79; p = 0.27), being a woman (coefficient = -9.4; 95% CI -24 to 5.3; p = 0.20), and more postoperative months (coefficient = 0.02; 95% CI -0.01 to 0.05]; p = 0.13). The mean postoperative VAS score for pain at rest was 3 ± 2. Flap necrosis occurred in 5% (seven of 130) of all patients, and failed innervation of the gracilis muscle occurred in 4% (five patients). CONCLUSION: FFMT achieves ROM with fair-to-good muscle power of elbow flexion, shoulder abduction, and overall function for the patient, but does not achieve good wrist function. Meticulous microsurgical skills and extensive rehabilitation training are needed to maximize the result of FFMT. Further technical developments in distal attachment and additional nerve procedures will pave the way for reconstructing a functional limb in patients with a flail upper extremity. LEVEL OF EVIDENCE: Level III, therapeutic study.

A prediction model for recurrence after translabyrinthine surgery for vestibular schwannoma: toward personalized postoperative surveillance.

PURPOSE: The aim of this study is to compute and validate a statistical predictive model for the risk of recurrence, defined as regrowth of tumor necessitating salvage treatment, after translabyrinthine removal of vestibular schwannomas to individualize postoperative surveillance. METHODS: The multivariable predictive model for risk of recurrence was based on retrospectively collected patient data between 1995 and 2017 at a tertiary referral center. To assess for internal validity of the prediction model tenfold cross-validation was performed. A 'low' calculated risk of recurrence in this study was set at < 1%, based on clinical criteria and expert opinion. RESULTS: A total of 596 patients with 33 recurrences (5.5%) were included for analysis. The final prediction model consisted of the predictors 'age at time of surgery', 'preoperative tumor growth' and 'first postoperative MRI outcome'. The area under the receiver operating curve of the prediction model was 89%, with a C-index of 0.686 (95% CI 0.614-0.796) after cross-validation. The predicted probability for risk of recurrence was low (< 1%) in 373 patients (63%). The earliest recurrence in these low-risk patients was detected at 46 months after surgery. CONCLUSION: This study presents a well-performing prediction model for the risk of recurrence after translabyrinthine surgery for vestibular schwannoma. The prediction model can be used to tailor the postoperative surveillance to the estimated risk of recurrence of individual patients. It seems that especially in patients with an estimated low risk of recurrence, the interval between the first and second postoperative MRI can be safely prolonged.

Timed GDNF gene therapy using an immune-evasive gene switch promotes long distance axon regeneration.

Neurosurgical repair in patients with proximal nerve lesions results in unsatisfactory recovery of function. Gene therapy for neurotrophic factors is a powerful strategy to promote axon regeneration. Glial cell line-derived neurotrophic factor (GDNF) gene therapy promotes motor neuron survival and axon outgrowth; however, uncontrolled delivery of GDNF results in axon entrapment. We report that time-restricted GDNF expression (1 month) using an immune-evasive doxycycline-inducible gene switch attenuated local axon entrapment in avulsed reimplanted ventral spinal roots, was sufficient to promote long-term motor neuron survival (24 weeks) and facilitated the recovery of compound muscle action potentials by 8 weeks. These improvements were associated with an increase in long-distance regeneration of motor axons. In contrast, persistent GDNF expression impaired axon regeneration by inducing axon entrapment. These findings demonstrate that timed expression can resolve the deleterious effect of uncontrolled growth factor delivery and shows that inducible growth factor gene therapy can be employed to enhance the efficacy of axon regeneration after neurosurgical repair of a proximal nerve lesion in rats. This preclinical study is an important step in the ongoing development of a neurotrophic factor gene therapy for patients with severe proximal nerve lesions.

Nerve injuries do occur in elbow arthroscopy.

PURPOSE: The purpose is to create more awareness as well as emphasize the risk of permanent nerve injury as a complication of elbow arthroscopy. METHODS: Patients who underwent elbow arthroscopy complicated by permanent nerve injury were retrospectively collected. Patients were collected using two strategies: (1) by word-of-mouth throughout the Dutch Society of Shoulder and Elbow Surgery, and the Leiden University Nerve Centre, and (2) approaching two medical liability insurance companies. Medical records were reviewed to determine patient characteristics, disease history and postoperative course. Surgical records were reviewed to determine surgical details. RESULTS: A total of eight patients were collected, four men and four women, ageing 21-54 years. In five out of eight patients (62.5%), the ulnar nerve was affected; in the remaining three patients (37.5%), the radial nerve was involved. Possible causes for nerve injury varied among patients, such as portal placement and the use of motorized instruments. CONCLUSIONS: A case series on permanent nerve injury as a complication of elbow arthroscopy is presented. Reporting on this sequel in the literature is little, however, its risk is not to be underestimated. This study emphasizes that permanent nerve injury is a complication of elbow arthroscopy, concurrently increasing awareness and thereby possibly aiding to prevention. LEVEL OF EVIDENCE: IV, case series.

Outcome of Carpal Tunnel Release and the Relation With Depression.

PURPOSE: To examine the relation between depressive symptoms and outcome of carpal tunnel release (CTR). METHODS: Prospective study in a general hospital with data collection at baseline and 3 and 12 months after CTR. We quantified depressive symptoms using the Center for Epidemiologic Studies Depression (CES-D) scale and performed multivariable analyses on 2 outcome measures: (1) carpal tunnel syndrome (CTS) symptoms (Boston Carpal Tunnel Questionnaire [BCTQ]) and (2) palmar pain, focusing on preoperative CES-D and BCTQ score, sex, age, alcohol use, diabetes, and severity of nerve conduction abnormalities. RESULTS: We included 227 patients. Before surgery, patients with depression had a higher BCTQ score than patients without depression. After 1 year, depressed patients had a higher BCTQ score and more palmar pain. The CES-D decreased by a median of 2 points from baseline to 1 year. This correlated with the decrease in BCTQ score. Multivariable analyses showed that preoperative depression had a small but statistically significant influence on palmar pain, but not on postoperative BCTQ score. CONCLUSIONS: Depression is not an independent predictor of residual CTS symptoms 1 year after CTR. Depressive symptoms in patients with CTS decrease after CTR, along with a decrease in CTS symptoms. The nature of this relationship is unknown. Patients with CTS and depression may expect a somewhat higher degree of palmar pain after CTR, the clinical relevance of which is small. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Current concepts in plasticity and nerve transfers: relationship between surgical techniques and outcomes.

OBJECTIVE Neuroplasticity is analyzed in this article as the capacity of the CNS to adapt to external and internal stimuli. It is being increasingly recognized as an important factor for the successful outcome of nerve transfers. Better-known factors are the number of axons that cross the coaptation site, the time interval between trauma and repair, and age. Neuroplasticity is mediated initially by synaptic and neurotransmitter changes. Over time, the activation of previously existing but lowly active connections in the brain cortex contributes further. Dendritic sprouting and axonal elongation might also take place but are less likely to be prominent. METHODS The authors reviewed different factors that play roles in neuroplasticity and functional regeneration after specific nerve transfers. RESULTS The authors found that these different factors include, among others, the distance between cortical areas of the donor and receptor neurons, the presence versus absence of preexisting lowly active interneuronal connections, gross versus fine movement restoration, rehabilitation, brain trauma, and age. CONCLUSIONS The potential for plasticity should be taken into consideration by surgeons when planning surgical strategy and postoperative rehabilitation, because its influence on results cannot be denied.

Anterior subcutaneous transposition for persistent ulnar neuropathy after neurolysis.

OBJECTIVE Little is known about optimal treatment if neurolysis for ulnar nerve entrapment at the elbow fails. The authors evaluated the clinical outcome of patients who underwent anterior subcutaneous transposition after failure of neurolysis of ulnar nerve entrapment (ASTAFNUE). METHODS A consecutive series of patients who underwent ASTAFNUE performed by a single surgeon between 2009 and 2014 was analyzed retrospectively. Preoperative and postoperative complaints in the following 3 clinical modalities were compared: pain and/or tingling, weakness, and numbness. Six-point satisfaction scores were determined on the basis of data from systematic telephonic surveys. RESULTS Twenty-six patients were included. The median age was 56 years (range 22-79 years). The median duration of complaints before ASTAFNUE was 23 months (range 8-78 months). The median interval between neurolysis and ASTAFNUE was 11 months (range 5-34 months). At presentation, 88% of the patients were experiencing pain and/or tingling, 46% had weakness, and 50% had numbness of the fourth and fifth fingers. Pain and/or tingling improved in 35%, motor function in 23%, and sensory disturbances in 19% of all the patients. Improvement in at least 1 of the 3 clinical modalities was found in 58%. However, a deterioration in 1 of the 3 modalities was noted in 46% of the patients. On the patient-satisfaction scale, 62% reported a good or excellent outcome. Patients with a good/excellent outcome were a median of 11 years younger than patients with a fair/poor outcome. No other factor was significantly related to satisfaction score. CONCLUSIONS A majority of the patients were satisfied after ASTAFNUE, even though their symptoms only partly resolved or even deteriorated. Older age is a risk factor for a poor outcome. Other factors that affect outcome might play a role, but they remain unidentified. One of these factors might be earlier surgical intervention. The modest results of ASTAFNUE should be mentioned when counseling patients after failure of neurolysis of ulnar nerve entrapment to manage their expectations. Patients, especially those who are elderly, might even consider not undergoing a secondary procedure. A randomized trial that includes a conservative treatment group and groups undergoing one of the several possible surgical procedures is needed to find the definitive answer for this clinical problem.

Botulinum Toxin Injection for Internal Rotation Contractures in Brachial Plexus Birth Palsy. A Minimum 5-Year Prospective Observational Study.

BACKGROUND: Brachial plexus birth palsy is frequently associated with internal rotation contractures of the shoulder as a result of muscle imbalance. The purpose of this study is to assess the effect of botulinum toxin A (BTX-A) injection in the subscapular (SC) muscle on external rotation and the need for tendon transfer for external rotation of the shoulder. METHODS: A prospective comparative study was performed including 15 consecutive patients treated with BTX-A and a historic control group of 67 patients with mean age 30 months (SD 10). The BTX-A injection (2 IU/kg body weight) was performed immediately following MRI under general anesthesia in the SC muscle. Passive external rotation, the need for tendon transfer surgery, glenohumeral deformity, and muscle degeneration were evaluated. The hazard ratio for no relapse of internal rotation contracture after BTX-A injection compared with no BTX-A injection was calculated. RESULTS: In the BTX-A group, the passive external rotation in adduction increased from -1 degree (95% CI, -10 to 8) to 32 degrees (95% CI, 17-46) at 3 months and 6 patients were indicated for surgery compared with a decline from -2 degrees (95% CI, -7 to 3) to -11 degrees (95% CI, -17 to -6) in the control group with 66 indications for surgery. At 5 years of follow-up, 10 patients in the BTX-A group were indicated for surgery with a hazard ratio of 4.0 (95% CI, 1.9 to 8.4). CONCLUSIONS: BTX-A injection in the SC muscle of brachial plexus birth palsy patients can reduce internal rotation contractures and subsequently the need for tendon transfer surgery. At 5 years of follow-up a relapse was seen in 67% of the patients treated with BTX-A. Because at MRI less SC degeneration was found in the good responders on BTX-A treatment, this group seems to be the best target group. Further research is needed on patient selection for BTX-A injection including glenohumeral deformity, SC degeneration, as well as doses of BTX-A to be used. LEVEL OF EVIDENCE: Level II-prospective comparative study.

Neuropathic Pain Due to Iatrogenic Lingual Nerve Lesion: Nerve Grafting to Reduce Otherwise Untreatable Pain.

Iatrogenic lingual nerve lesion is a well-known and unfortunate complication after mandibular third molar removal. Occasionally, the nerve injury can cause severe neuropathic pain.Here, the authors present the history of 2 patients with lingual nerve injury due to mandibular third molar removal, and with severe neuropathic pain in the craniomandibular region. Pharmacotherapy and physiotherapy did not reduce the pain, and ultimately, the lingual nerve was surgically explored. Scar tissue and a lingual nerve neuroma were observed and resected in both patients.In the first patient, the gap between the nerve stumps was bridged with an autologous sural nerve graft. In the second patient, some continuity of the lingual nerve was preserved and the resected part was substituted with an autologous sural nerve graft. Significant pain reduction was achieved in both patients and no further medical treatment was necessary at the end of follow-up.These reports show that lingual nerve reconstruction can be a successful therapy in patients experiencing severe neuropathic pain after iatrogenic lingual nerve injury. Different treatment options for neuropathic pain due to lingual nerve injury are discussed.

Clinical and neurobiological advances in promoting regeneration of the ventral root avulsion lesion.

Root avulsions due to traction to the brachial plexus causes complete and permanent loss of function. Until fairly recent, such lesions were considered impossible to repair. Here we review clinical repair strategies and current progress in experimental ventral root avulsion lesions. The current gold standard in patients with a root avulsion is nerve transfer, whereas reimplantation of the avulsed root into the spinal cord has been performed in a limited number of cases. These neurosurgical repair strategies have significant benefit for the patient but functional recovery remains incomplete. Developing new ways to improve the functional outcome of neurosurgical repair is therefore essential. In the laboratory, the molecular and cellular changes following ventral root avulsion and the efficacy of intervention strategies have been studied at the level of spinal motoneurons, the ventral spinal root and peripheral nerve, and the skeletal muscle. We present an overview of cell-based pharmacological and neurotrophic factor treatment approaches that have been applied in combination with surgical reimplantation. These interventions all demonstrate neuroprotective effects on avulsed motoneurons, often accompanied with various degrees of axonal regeneration. However, effects on survival are usually transient and robust axon regeneration over long distances has as yet not been achieved. Key future areas of research include finding ways to further extend the post-lesion survival period of motoneurons, the identification of neuron-intrinsic factors which can promote persistent and long-distance axon regeneration, and finally prolonging the pro-regenerative state of Schwann cells in the distal nerve.

The Tinel sign has no diagnostic value for nerve entrapment or neuropathy in the legs.

INTRODUCTION: The presence of a Tinel sign in leg nerves has been proposed as a criterion for decompressive surgery in polyneuropathy. We investigated the diagnostic yield of the Tinel sign for nerve entrapment and for distal symmetrical peripheral neuropathy (DSPN). METHODS: We prospectively tested for the Tinel sign at 3 sites of possible nerve entrapment per leg in 91 patients. Entrapment was defined using nerve conduction data. We also investigated whether the number of sites at which the Tinel sign was present identified patients with DSPN. RESULTS: Sensitivity of the Tinel sign for nerve entrapment was low (29%, 44%, and 17%) for the 3 sites, and specificity was moderate (86%, 75%, and 81%). In the subgroup with DSPN, sensitivity was extremely low (0%, 20%, and 8%), and specificity was moderate (91%, 79%, and 73%). The number of sites with a Tinel sign did not identify patients with DSPN. CONCLUSION: The Tinel sign does not reliably indicate nerve entrapment or DSPN. Muscle Nerve 54: 25-30, 2016.

International Federation of Societies for Surgery of the Hand Committee report: the role of nerve transfers in the treatment of neonatal brachial plexus palsy.

Nerve transfers have gained popularity in the treatment of adult brachial plexus palsy; however, their role in the treatment of neonatal brachial plexus palsy (NBPP) remains unclear. Brachial plexus palsies in infants differ greatly from those in adults in the patterns of injury, potential for recovery, and influences of growth and development. This International Federation of Societies for Surgery of the Hand committee report on NBPP is based upon review of the current literature. We found no direct comparisons of nerve grafting to nerve transfer for primary reconstruction of NBPP. Although the results contained in individual reports that use each strategy for treatment of Erb palsy are similar, comparison of nerve transfer to nerve grafting is limited by inconsistencies in outcomes reported, by multiple confounding factors, and by small numbers of patients. Although the role of nerve transfers for primary reconstruction remains to be defined, nerve transfers have been found to be effective and useful in specific clinical circumstances including late presentation, isolated deficits, failed primary reconstruction, and multiple nerve root avulsions. In the case of NBPP more severe than Erb palsy, nerve transfers alone are inadequate to address all of the deficits and should only be considered as adjuncts if maximal re-innervation is to be achieved. Surgeons who commit to care of infants with NBPP need to avoid an over-reliance on nerve transfers and should also have the capability and inclination for brachial plexus exploration and nerve graft reconstruction.

Extensive motor axonal misrouting after conservative treatment of obstetric brachial plexus lesions.

AIM: The aim of this cross-sectional study was to assess systematically motor function and motor misrouting in adults with conservatively treated obstetric brachial plexus lesion (OBPL). METHOD: Seventeen adults with OBPL (median age 38y; five males, 12 females) and 16 comparison participants (median age 26y; eight males, eight females) were investigated. Motor function in the group with OBPL was assessed through passive and active motion, muscle strength of the deltoid, biceps, and triceps muscles, and Mallet aggregate score and five subscores. Motor misrouting was quantified by electrically stimulating each of 10 arm muscles and recording activity from the other nine in response to this. Motor function and motor misrouting were statistically analysed using the Mann-Whitney U test and Spearman's correlation coefficient. RESULTS: Motor function testing showed excellent strength but poor functional Mallet scores. Participants with OBPL had significantly more motor misrouting than comparison participants (Mann-Whitney U=31.5 [df=28], p<0.001, median difference=-4.00, 95% confidence interval [CI]=-7.00 to -1.00). Most misrouting was observed when stimulating the biceps (Mann-Whitney U=38.5 [df=31], p<0.001, median difference=-3.00, 95% CI -3.00 to -1.00), deltoid (Mann-Whitney U=68.5 [df=31], p=0.003, median difference=-1.0, 95% CI=-4.00 to 0.00 <0.001) and brachioradialis muscles (Mann-Whitney U=72.0 [df=31], p=0.002, median difference <0.001, 95% CI=-3.00 to 0.00 <0.001). There were no significant correlations between the presence of motor misrouting and impairment of motor function. INTERPRETATION: There is extensive motor misrouting in conservatively treated OBPL. The presence of this, in addition to motor functional impairment, suggests that motor misrouting should be further studied in OBPL.