Motor recovery and the breathing arm after brachial plexus surgical repairs, including re-implantation of avulsed spinal roots into the spinal cord

Differences in management and treatment of traumatic adult pan brachial plexus injuries: a global perspective regarding continental variations

An expert opinion study was designed to query five countries and six brachial plexus surgeons regarding the demographics, mechanisms of injury, evaluation, timing of surgery, reconstructive strategies and controversies in adult traumatic pan brachial plexus injuries. Variations in assessing outcomes, management of neuropathic pain and future considerations were elucidated. Clear differences in regional demographics, mechanisms of injury, patient evaluation and treatment strategies were identified. The role of phrenic nerve and contralateral C7 transfer, acute use of free functioning muscle transfers, root reimplantation and amputation/myoelectric prosthetic fitting were regional/surgeon dependent. Comparison of outcomes across regions requires an understanding of the regional nuances of patient demographics, injury mechanisms, preferred reconstructive strategies and how outcomes are measured. Future studies are required to allow accurate regional comparisons.

GDNF Gene Therapy to Repair the Injured Peripheral Nerve

A spinal root avulsion is the most severe proximal peripheral nerve lesion possible. Avulsion of ventral root filaments disconnects spinal motoneurons from their target muscles, resulting in complete paralysis. In patients that undergo brachial plexus nerve repair, axonal regeneration is a slow process. It takes months or even years to bridge the distance from the lesion site to the distal targets located in the forearm. Following ventral root avulsion, without additional pharmacological or surgical treatments, progressive death of motoneurons occurs within 2 weeks (Koliatsos et al., 1994). Reimplantation of the avulsed ventral root or peripheral nerve graft can act as a conduit for regenerating axons and increases motoneuron survival (Chai et al., 2000). However, this beneficial effect is transient. Combined with protracted and poor long-distance axonal regeneration, this results in permanent function loss. To overcome motoneuron death and improve functional recovery, several promising intervention strategies are being developed. Here, we focus on GDNF gene-therapy. We first introduce the experimental ventral root avulsion model and discuss its value as a proxy to study clinical neurotmetic nerve lesions. Second, we discuss our recent studies showing that GDNF gene-therapy is a powerful strategy to promote long-term motoneuron survival and improve function when target muscle reinnervation occurs within a critical post-lesion period. Based upon these observations, we discuss the influence of timing of the intervention, and of the duration, concentration and location of GDNF delivery on functional outcome. Finally, we provide a perspective on future research directions to realize functional recovery using gene therapy.

Phrenic to musculocutaneous nerve transfer for traumatic brachial plexus injuries: analyzing respiratory effects on elbow flexion control

OBJECTIVE

In this study, the authors sought to identify the relationship between breathing and elbow flexion in patients with a traumatic brachial plexus injury (TBPI) who undergo a phrenic nerve (PN) transfer to restore biceps flexion. More specifically, the authors studied whether biceps strength and the maximal range of active elbow flexion differ between full inspiration and expiration, and whether electromyography (EMG) activity in the biceps differs between forced maximum breathing during muscular rest, normal breathing during rest, and at maximal biceps contraction. All these variables were studied in a cohort with different intervals of follow-up, as the authors sought to determine if the relationship between breathing movements and elbow flexion changes over time.

METHODS

The British Medical Research Council muscle-strength grading system and a dynamometer were used to measure biceps strength, which was measured 1) during a maximal inspiratory effort, 2) during respiratory repose, and 3) after a maximal expiratory effort. The maximum range of elbow flexion was measured 1) after maximal inspiration, 2) during normal breathing, and 3) after maximal expiration. Postoperative EMG testing was performed 1) during normal breathing with the arm at rest, 2) during sustained maximal inspiration with the arm at rest, and 3) during maximal voluntary biceps contraction. Within-group (paired) comparisons, and both correlation and regression analyses were performed.

RESULTS

Twenty-one patients fit the study inclusion criteria. The mean interval from trauma to surgery was 5.5 months, and the mean duration of follow-up 2.6 years (range 10 months to 9.6 years). Mean biceps strength was 0.21 after maximal expiration versus 0.29 after maximal inspiration, a difference of 0.08 (t = 4.97, p < 0.001). Similarly, there was almost a 21° difference in maximum elbow flexion, from 88.8° after expiration to 109.5° during maximal inspiration (t = 5.05, p < 0.001). Involuntary elbow flexion movement during breathing was present in 18/21 patients (86%) and averaged almost 20°. Measuring involuntary EMG activity in the biceps during rest and contraction, there were statistically significant direct correlations between readings taken during normal and deep breathing, which were moderate (r = 0.66, p < 0.001) and extremely strong (r = 0.94, p < 0.001), respectively. Involuntary activity also differed significantly between normal and deep breathing (2.14 vs 3.14, t = 4.58, p < 0.001). The degrees of involuntary flexion were significantly greater within the first 2.6 years of follow-up than later.

CONCLUSIONS

These results suggest that the impact of breathing on elbow function is considerable after PN transfer for elbow function reconstruction following a TBPI, both clinically and electromyographically, but also that there may be some waning of this influence over time, perhaps secondary to brain plasticity. In the study cohort, this waning impacted elbow range of motion more than biceps muscle strength and EMG recordings.

Network-centric medicine for peripheral nerve injury: Treating the whole to boost endogenous mechanisms of neuroprotection and regeneration

Peripheral nerve injuries caused by accidents may lead to paralysis, sensory disturbances, anaesthesia, and lack of autonomic functions. Functional recovery after disconnection of the motoneuronal soma from target tissue with proximal rupture of axons is determined by several factors: motoneuronal soma viability, proper axonal sprouting across inhibitory zones and elongation toward specific muscle, effective synapse contact rebuilding, and prevention of muscle atrophy. Therapies, such as adjuvant drugs with pleiotropic effects, that promote functional recovery after peripheral nerve injury are needed. Toward this aim, we designed a drug discovery workflow based on a network-centric molecular vision using unbiased proteomic data and neural artificial computational tools. Our focus is on boosting intrinsic capabilities of neurons for neuroprotection; this is in contrast to the common approach based on suppression of a pathobiological pathway known to be associated with disease condition. Using our workflow, we discovered neuroheal, a combination of two repurposed drugs that promotes motoneuronal soma neuroprotection, is anti-inflammatory, enhances axonal regeneration after axotomy, and reduces muscle atrophy. This drug discovery workflow has thus yielded a therapy that is close to its clinical application.

Pretreatment of nerve grafts with resveratrol improves axonal regeneration following replantation surgery for nerve root avulsion injury in rats

BACKGROUND

Replantation of the avulsed nerve root has been proposed for the treatment of severe brachial plexus injury for several decades. However, due to the complexity of the technique and limited functional improvement, practical applications are yet to be implemented.

OBJECTIVE

In the present study, we investigated the effect of pretreatment with resveratrol on nerve autografts used for replantation surgery in a rat model of nerve root avulsion.

METHODS

Resveratrol pretreatment was performed using an explant culture technique. Two surgical procedures were performed. During the first surgery, Sprague-Dawley rats were subjected to left C6 nerve root avulsion, and nerves were harvested for autografting. The harvested grafts were explant-cultured for 1 week. A second procedure was performed to replant the C6 nerve root using the explant-cultured nerve graft 1 week after the first procedure. Histological and immunohistochemical analyses were performed 8 weeks after the second procedure. We first compared findings between explant-cultured nerve grafts and fresh nerve grafts, following which we compared findings between explant-cultured grafts pretreated with and without resveratrol. Changes induced within nerve grafts by 1 week of explant culture with or without resveratrol were investigated in vitro.

RESULTS

There was no significant difference in outcomes between 1 week-explant-cultured and fresh nerve grafts. Addition of resveratrol to the explant culture medium resulted in a significant increase in the number and myelin thickness of regenerated axons, and in the number of regenerating motor neurons in the C6 spinal cord segment. In vitro analyses revealed that nerve grafts pretreated with resveratrol exhibited significant increases in glial cell line-derived neurotrophic factor (GDNF) expression and the number of dedifferentiated Schwann cells.

CONCLUSIONS

Resveratrol may promote axonal regeneration following replantation surgery for the treatment of nerve root avulsion injury; however, further studies are required to verify these findings in humans.

Clinical and Neurophysiological Changes after Targeted Intrathecal Injections of Bone Marrow Stem Cells in a C3 Tetraplegic Subject

High-level quadriplegia is a devastating condition with limited treatment options. Bone marrow derived stem cells (BMSCs) are reported to have immunomodulatory and neurotrophic effects in spinal cord injury (SCI). We report a subject with complete C2 SCI who received three anatomically targeted intrathecal infusions of BMSCs under a single-patient expanded access investigational new drug (IND). She underwent intensive physical therapy and was followed for >2 years. At end-point, her American Spinal Injury Association Impairment Scale (AIS) grade improved from A to B, and she recovered focal pressure touch sensation over several body areas. We conducted serial neurophysiological testing to monitor changes in residual connectivity. Motor, sensory, and autonomic system testing included motor evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), electromyography (EMG) recordings, F waves, galvanic skin responses, and tilt-table responses. The quality and magnitude of voluntary EMG activations increased over time, but remained below the threshold of clinically obvious movement. Unexpectedly, at 14 months post-injury, deep inspiratory maneuvers triggered respiratory-like EMG bursting in the biceps and several other muscles. This finding means that connections between respiratory neurons and motor neurons were newly established, or unmasked. We also report serial analysis of MRI, International Standards for Neurological Classification of SCI (ISNCSCI), pulmonary function, pain scores, cerebrospinal fluid (CSF) cytokines, and bladder assessment. As a single case, the linkage of the clinical and neurophysiological changes to either natural history or to the BMSC infusions cannot be resolved. Nevertheless, such detailed neurophysiological assessment of high cervical SCI patients is rarely performed. Our findings indicate that electrophysiology studies are sensitive to define both residual connectivity and new plasticity.

Surgical reconstruction of spinal cord circuit provides functional return in humans

This mini review describes the current surgical strategy for restoring function after traumatic spinal nerve root avulsion in brachial or lumbosacral plexus injury in man. As this lesion is a spinal cord or central nervous injury functional return depends on spinal cord nerve cell growth within the central nervous system. Basic science, clinical research and human application has demonstrated good and useful motor function after ventral root avulsion followed by spinal cord reimplantation. Recently, sensory return could be demonstrated following spinal cord surgery bypassing the injured primary sensory neuron. Experimental data showed that most of the recovery depended on new growth reinnervating peripheral receptors. Restored sensory function and the return of spinal reflex was demonstrated by electrophysiology and functional magnetic resonance imaging of human cortex. This spinal cord surgery is a unique treatment of central nervous system injury resulting in useful functional return. Further improvements will not depend on surgical improvements. Adjuvant therapy aiming at ameliorating the activity in retinoic acid elements in dorsal root ganglion neurons could be a new therapeutic avenue in restoring spinal cord circuits after nerve root avulsion injury.

Early nerve repair in traumatic brachial plexus injuries in adults: treatment algorithm and first experiences

OBJECTIVE

The object of this study was to assess the advantages and disadvantages of early nerve repair within 2 weeks following adult traumatic brachial plexus injury (ATBPI).

METHODS

From 2009 onwards, the authors have strived to repair as early as possible extended C-5 to C-8 or T-1 lesions or complete loss of C-5 to C-6 or C-7 function in patients in whom there was clinical and radiological suspicion of root avulsion. Among a group of 36 patients surgically treated in the period between 2009 and 2011, surgical findings in those who had undergone treatment within 2 weeks after trauma were retrospectively compared with results in those who had undergone delayed treatment. The result of biceps muscle reanimation was the primary outcome measure.

RESULTS

Five of the 36 patients were referred within 2 weeks after trauma and were eligible for early surgery. Nerve ruptures and/or avulsions were found in all early cases of surgery. The advantages of early surgery are as follows: no scar formation, easy anatomical identification, and gap length reduction. Disadvantages include less-clear demarcation of vital nerve tissue and unfamiliarity with the interpretation of frozen-section examination findings. All 5 early-treatment patients recovered a biceps force rated Medical Research Council grade 4.

CONCLUSIONS

Preliminary results of nerve repair within 2 weeks of ATBPI are encouraging, and the benefits outweigh the drawbacks. The authors propose a decision algorithm to select patients eligible for early surgery. Referral standards for patients with ATBPI must be adapted to enable early surgery.

Structural and Functional Substitution of Deleted Primary Sensory Neurons by New Growth from Intrinsic Spinal Cord Nerve Cells: An Alternative Concept in Reconstruction of Spinal Cord Circuits

In a recent clinical report, return of the tendon stretch reflex was demonstrated after spinal cord surgery in a case of total traumatic brachial plexus avulsion injury. Peripheral nerve grafts had been implanted into the spinal cord to reconnect to the peripheral nerves for motor and sensory function. The dorsal root ganglia (DRG) containing the primary sensory nerve cells had been surgically removed in order for secondary or spinal cord sensory neurons to extend into the periphery and replace the deleted DRG neurons. The present experimental study uses a rat injury model first to corroborate the clinical finding of a re-established spinal reflex arch, and second, to elucidate some of the potential mechanisms underlying these findings by means of morphological, immunohistochemical, and electrophysiological assessments. Our findings indicate that, after spinal cord surgery, the central nervous system sensory system could replace the traumatically detached original peripheral sensory connections through new neurite growth from dendrites.

Long-Term Outcome of Brachial Plexus Reimplantation After Complete Brachial Plexus Avulsion Injury

Background

Complete brachial plexus avulsion injury is a severe disabling injury due to traction to the brachial plexus. Brachial plexus reimplantation is an emerging surgical technique for the management of complete brachial plexus avulsion injury.

Objective

We assessed the functional recovery in 15 patients who underwent brachial plexus reimplantation surgery after complete brachial plexus avulsion injury with clinical examination and electrophysiological testing.

Methods

We included all patients who underwent brachial plexus reimplantation in our institution between 1997 and 2010. Patients were assessed with detailed motor and sensory clinical examination and motor and sensory electrophysiological tests.

Results

We found that patients who had reimplantation surgery demonstrated an improvement in Medical Research Council power in the deltoid, pectoralis, and infraspinatous muscles and global Medical Research Council score. Eight patients achieved at least grade 3 MRC power in at least one muscle group of the arm. Improved reinnervation by electromyelography criteria was found in infraspinatous, biceps, and triceps muscles. There was evidence of ongoing innervation in 3 patients. Sensory testing in affected dermatomes also showed better recovery at C5, C6, and T1 dermatomes. The best recovery was seen in the C5 dermatome.

Conclusions

Our results demonstrate a definite but limited improvement in motor and sensory recovery after reimplantation surgery in patients with complete brachial plexus injury. We hypothesize that further improvement may be achieved by using regenerative cell technologies at the time of repair.

New Treatments for Spinal Nerve Root Avulsion Injury

Further progress in the treatment of the longitudinal spinal cord injury has been made. In an inverted translational study, it has been demonstrated that return of sensory function can be achieved by bypassing the avulsed dorsal root ganglion neurons. Dendritic growth from spinal cord sensory neurons could replace dorsal root ganglion axons and re-establish a reflex arch. Another research avenue has led to the development of adjuvant therapy for regeneration following dorsal root to spinal cord implantation in root avulsion injury. A small, lipophilic molecule that can be given orally acts on the retinoic acid receptor system as an agonist. Upregulation of dorsal root ganglion regenerative ability and organization of glia reaction to injury were demonstrated in treated animals. The dual effect of this substance may open new avenues for the treatment of root avulsion and spinal cord injuries.

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.

Upper brachial plexus injury in adults: comparative effectiveness of different repair techniques

OBJECT

Adult upper trunk brachial plexus injuries result in significant disability. Several surgical treatment strategies exist, including nerve grafting, nerve transfers, and a combination of both approaches. However, no existing data clearly indicate the most successful strategy for restoring elbow flexion and shoulder abduction in these patients. The authors reviewed the literature to compare outcomes of the three surgical repair techniques listed above to determine the optimal approach to traumatic injury to the upper brachial plexus in adults.

METHODS

Both PubMed and EMBASE databases were searched for English-language articles containing the MeSH topic "brachial plexus" in conjunction with the word "injury" or "trauma" in the title and "surgery" or "repair" as a MeSH subheading or in the title, excluding pediatric articles and those articles limited to avulsions. The search was also limited to articles published after 1990 and containing at least 10 operated cases involving upper brachial plexus injuries. The search was supplemented with articles obtained through the "Related Articles" feature on PubMed and the bibliographies of selected publications. From the articles was collected information on the operation performed, number of operated cases, mean subject ages, sex distribution, interval between injury and surgery, source of nerve transfers, mean duration of follow-up, year of publication, and percentage of operative success in terms of elbow flexion and shoulder abduction of the injured limb. The recovery of elbow flexion and shoulder abduction was separately analyzed. A subanalysis was also performed to assess the recovery of elbow flexion following various neurotization techniques.

RESULTS

As regards the restoration of elbow flexion, nerve grafting led to significantly better outcomes than either nerve transfer or the combined techniques (F = 4.71, p = 0.0097). However, separating the Oberlin procedure from other neurotization techniques revealed that the former was significantly more successful (F = 82.82, p < 0.001). Moreover, in comparing the Oberlin procedure to nerve grafting or combined procedures, again the former was significantly more successful than either of the latter two approaches (F = 53.14; p < 0.001). In the restoration of shoulder abduction, nerve transfer was significantly more successful than the combined procedure (p = 0.046), which in turn was significantly better than nerve grafting procedures (F = 5.53, p = 0.0044).

CONCLUSIONS

According to data in this study, in upper trunk brachial plexus injuries in adults, the Oberlin procedure and nerve transfers are the more successful approaches to restore elbow flexion and shoulder abduction, respectively, compared with nerve grafting or combined techniques. A prospective, randomized controlled trial would be necessary to fully elucidate differences in outcome among the various surgical approaches.

Synaptic rearrangement following axonal injury: Old and new players

Following axotomy, the contact between motoneurons and muscle fibers is disrupted, triggering a retrograde reaction at the neuron cell body within the spinal cord. Together with chromatolysis, a hallmark of such response to injury is the elimination of presynaptic terminals apposing to the soma and proximal dendrites of the injured neuron. Excitatory inputs are preferentially eliminated, leaving the cells under an inhibitory influence during the repair process. This is particularly important to avoid glutamate excitotoxicity. Such shift from transmission to a regeneration state is also reflected by deep metabolic changes, seen by the regulation of several genes related to cell survival and axonal growth. It is unclear, however, how exactly synaptic stripping occurs, but there is substantial evidence that glial cells play an active role in this process. In one hand, immune molecules, such as the major histocompatibility complex (MHC) class I, members of the complement family and Toll-like receptors are actively involved in the elimination/reapposition of presynaptic boutons. On the other hand, plastic changes that involve sprouting might be negatively regulated by extracellular matrix proteins such as Nogo-A, MAG and scar-related chondroitin sulfate proteoglycans. Also, neurotrophins, stem cells, physical exercise and several drugs seem to improve synaptic stability, leading to functional recovery after lesion. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'.

Bridging defects in chronic spinal cord injury using peripheral nerve grafts combined with a chitosan-laminin scaffold and enhancing regeneration through them by co-transplantation with bone-marrow-derived mesenchymal stem cells: case series of 14 patients

OBJECTIVE

To investigate the effect of bridging defects in chronic spinal cord injury using peripheral nerve grafts combined with a chitosan-laminin scaffold and enhancing regeneration through them by co-transplantation with bone-marrow-derived mesenchymal stem cells.

METHODS

In 14 patients with chronic paraplegia caused by spinal cord injury, cord defects were grafted and stem cells injected into the whole construct and contained using a chitosan-laminin paste. Patients were evaluated using the International Standards for Classification of Spinal Cord Injuries.

RESULTS

Chitosan disintegration leading to post-operative seroma formation was a complication. Motor level improved four levels in 2 cases and two levels in 12 cases. Sensory-level improved six levels in two cases, five levels in five cases, four levels in three cases, and three levels in four cases. A four-level neurological improvement was recorded in 2 cases and a two-level neurological improvement occurred in 12 cases. The American Spinal Impairment Association (ASIA) impairment scale improved from A to C in 12 cases and from A to B in 2 cases. Although motor power improvement was recorded in the abdominal muscles (2 grades), hip flexors (3 grades), hip adductors (3 grades), knee extensors (2-3 grades), ankle dorsiflexors (1-2 grades), long toe extensors (1-2 grades), and plantar flexors (0-2 grades), this improvement was too low to enable them to stand erect and hold their knees extended while walking unaided.

CONCLUSION

Mesenchymal stem cell-derived neural stem cell-like cell transplantation enhances recovery in chronic spinal cord injuries with defects bridged by sural nerve grafts combined with a chitosan-laminin scaffold.

Effective reinnervation of the quadriceps femoris by spinal ventral root cross-anastomosis in rats

PURPOSE: To study the effective recovery of the quadriceps femoris by spinal ventral root cross-anastomosis in rats. METHODS: End-to-end anastomosis was performed between the left L1 and L3 ventral roots using autogenous nerve graft ,and the right L1 and L3 roots were left intact. In control animals, the left L3 ventral root was cut and shortened, and anastomosis was not performed. Six months postoperatively, the movement of low extremities was detected by electrophysiological examination, hindlimb locomotion and basso, beattie and bresnahan (BBB) scoring at one, three, seven, 14, 21 and 28 days after SCI. Fluorescence retrograde tracing with TRUE BLUE (TB) and HE staining were performed to observe the nerve regeneration. RESULTS: Six months after surgery, the anastomotic nerve was smooth and not atrophic. The amplitudes of action potential were 7.63±1.86 mV and 6.0±1.92 mV respectively before and after the spinal cord hemisection. The contraction of left quadriceps femoris was induced by a single stimulation of the anastomotic nerve. The locomotion of left hindlimb was partially restored after spinal cord hemisection while creeping and climbing. In addition, there was significant difference in the BBB score at one, three and seven days after SCI. TB retrograde tracing and neurophysiologic observation indicated efficient reinnervation of the quadriceps femoris. CONCLUSION: The cross-anastomosis between spinal ventral root can partially reconstruct the function of quadriceps femoris following SCI and may have clinical implication for the treatment of human SCI.

The longitudinal spinal cord injury: lessons from intraspinal plexus, cauda equina and medullary conus lesions

Spinal nerve root avulsion injury interrupts the transverse segmental spinal cord nerve fibers. There is degeneration of sensory, motor, and autonomic axons, loss of synapses, deterioration of local segmental connections, nerve cell death, and reactions among non neuronal cells with central nerve system (CNS) scar formation, i.e., a cascade of events similar to those known to occur in any injury to the spinal cord. This is the longitudinal spinal cord injury (SCI). For function to be restored, nerve cells must survive and there must be regrowth of new nerve fibers along a trajectory consisting of CNS growth-inhibitory tissue in the spinal cord as well as peripheral nervous system (PNS) growth-promoting tissue in nerves. Basic science results have been translated into a successful surgical strategy to treat root avulsion injuries in man. In humans, this technique is currently the most promising treatment of any spinal cord injury, with return of useful muscle function together with pain alleviation. Experimental studies have also identified potential candidates for adjunctive therapies that, together with surgical replantation of avulsed roots after brachial plexus and cauda equina injuries, can restore not only motor but also autonomic and sensory trajectories to augment the recovery of neurological function. This is the first example of a spinal cord lesion that can be treated surgically, leading to restoration of somatic and autonomic activity and alleviation of pain.

Biomedical and psychosocial factors associated with disability after peripheral nerve injury

BACKGROUND

The purpose of this study was to evaluate the biomedical and psychosocial factors associated with disability at a minimum of six months following upper-extremity nerve injury.

METHODS

This cross-sectional study included patients who were assessed between six months and fifteen years following an upper-extremity nerve injury. Assessment measures included patient self-report questionnaires (the Disabilities of the Arm, Shoulder and Hand Questionnaire [DASH]; pain questionnaires; and general health and mental health questionnaires). DASH scores were compared by using unpaired t tests (sex, Workers' Compensation/litigation, affected limb, marital status, education, and geographic location), analysis of variance (nerve injured, work status, and income), or correlations (age and time since injury). Multivariable linear regression analysis was used to evaluate the predictors of the DASH scores.

RESULTS

The sample included 158 patients with a mean age (and standard deviation) of 41 ± 16 years. The median time from injury was fourteen months (range, six to 167 months). The DASH scores were significantly higher for patients receiving Workers' Compensation or involved in litigation (p = 0.02), had a brachial plexus injury (p = 0.001), or were unemployed (p < 0.001). There was a significant positive correlation between the DASH scores and pain intensity (r = 0.51, p < 0.001). In the multivariable regression analysis of the predictors of the DASH scores, the following predictors explained 52.7% of the variance in the final model: pain intensity (Beta = 0.230, p = 0.006), brachial plexus injury (Beta = -0.220, p = 0.000), time since injury (Beta = -0.198, p = 0.002), pain catastrophizing score (Beta = 0.192, p = 0.025), age (Beta = 0.187, p = 0.002), work status (Beta = 0.179, p = 0.008), cold sensitivity (Beta = 0.171, p = 0.015), depression score (Beta = 0.133, p = 0.066), Workers' Compensation/litigation (Beta = 0.116, p = 0.049), and female sex (Beta = -0.104, p = 0.090).

CONCLUSIONS

Patients with a peripheral nerve injury report substantial disability, pain, and cold sensitivity. Disability as measured with the DASH was predicted by brachial plexus injury, older age, pain intensity, work status, time since injury, cold sensitivity, and pain catastrophizing.

Cellular and paracellular transplants for spinal cord injury: a review of the literature

BACKGROUND

Experimental approaches to limit the spinal cord injury and to promote neurite outgrowth and improved function from a spinal cord injury have exploded in recent decades. Due to the cavitation resulting after a spinal cord injury, newer important treatment strategies have consisted of implanting scaffolds with or without cellular transplants. There are various scaffolds, as well as various different cellular transplants including stem cells at different levels of differentiation, Schwann cells and peripheral nerve implants, that have been reviewed. Also, attention has been given to different re-implantation techniques in avulsion injuries.

METHODS

Using standard search engines, this literature is reviewed.

CONCLUSION

Cellular and paracellular transplantation for application to spinal cord injury offers promising results for those patients with spinal cord pathology.

Novel strategies in brachial plexus repair after traumatic avulsion

Clinical trials in spinal cord injury (SCI) can be affected by many confounding variables including spontaneous recovery, variation in the lesion type and extend. However, the clinical need and the paucity of effective therapies has spawned a large number of animal studies and clinical trials for SCI. In this review, we suggest that brachial plexus avulsion injury, a longitudinal spinal cord lesion, is a simpler model to test methods of spinal cord repair. We explore reconstructive techniques currently explored for the repair of brachial plexus avulsion and focus on the use of olfactory ensheathing cell transplantation as an adjunct treatment in brachial plexus repair.

The lateral approach to intraspinal reimplantation of the brachial plexus: a technical note

Intraspinal re-implantation after traumatic avulsion of the brachial plexus is a relatively new technique. Three different approaches to the spinal cord have been described to date, namely the posterior scapular, anterolateral interscalenic multilevel oblique corpectomy and the pure lateral. We describe an anatomical study of the pure lateral approach, based on our clinical experience and studies on cadavers.

Cortical activity and hand function restoration in a patient after spinal cord surgery

BACKGROUND

Following a motorcycle accident, a 9-year-old boy experienced a complete right-sided (dominant) arm and hand paralysis with total sensory loss, Horner syndrome and severe constant pain. This study assessed the long-term outcome of spinal cord surgery undertaken on the patient, focusing on the restored hand function and related cortical activity. The study follows on from previous reports on the same patient.

INVESTIGATIONS

Clinical functional and electrophysiological examinations. Functional MRI of cortical activity.

DIAGNOSIS

Complete brachial plexus (C5-T1) avulsion from the spinal cord.

MANAGEMENT

Spinal cord surgery to restore motor trajectories.

Direct cord implantation in brachial plexus avulsions: revised technique using a single stage combined anterior (first) posterior (second) approach and end-to-side side-to-side grafting neurorrhaphy

BACKGROUND

The superiority of a single stage combined anterior (first) posterior (second) approach and end-to-side side-to-side grafting neurorrhaphy in direct cord implantation was investigated as to providing adequate exposure to both the cervical cord and the brachial plexus, as to causing less tissue damage and as to being more extensible than current surgical approaches.

METHODS

The front and back of the neck, the front and back of the chest up to the midline and the whole affected upper limb were sterilized while the patient was in the lateral position; the patient was next turned into the supine position, the plexus explored anteriorly and the grafts were placed; the patient was then turned again into the lateral position, and a posterior cervical laminectomy was done. The grafts were retrieved posteriorly and side grafted to the anterior cord. Using this approach, 5 patients suffering from complete traumatic brachial plexus palsy, 4 adults and 1 obstetric case were operated upon and followed up for 2 years. 2 were C5,6 ruptures and C7,8T1 avulsions. 3 were C5,6,7,8T1 avulsions. C5,6 ruptures were grafted and all avulsions were cord implanted.

RESULTS

Surgery in complete avulsions led to Grade 4 improvement in shoulder abduction/flexion and elbow flexion. Cocontractions occurred between the lateral deltoid and biceps on active shoulder abduction. No cocontractions occurred after surgery in C5,6 ruptures and C7,8T1 avulsions, muscle power improvement extended into the forearm and hand; pain disappeared. LIMITATIONS INCLUDE: spontaneous recovery despite MRI appearance of avulsions, fallacies in determining intraoperative avulsions (wrong diagnosis, wrong level); small sample size; no controls rule out superiority of this technique versus other direct cord reimplantation techniques or other neurotization procedures; intra- and interobserver variability in testing muscle power and cocontractions.

CONCLUSION

Through providing proper exposure to the brachial plexus and to the cervical cord, the single stage combined anterior (first) and posterior (second) approach might stimulate brachial plexus surgeons to go more for direct cord implantation. In this study, it allowed for placing side grafts along an extensive donor recipient area by end-to-side, side-to-side grafting neurorrhaphy and thus improved results.

LEVEL OF EVIDENCE

Level IV, prospective case series.

Combination of microsurgery and gene therapy for spinal dorsal root injury repair

Brachial plexus injury is frequent after traffic accident in adults or shoulder dystocia in newborns. Whereas surgery can restore arm movements, therapeutic options are missing for sensory defects. Dorsal root (DR) ganglion neurons convey sensory information to the central nervous system (CNS) through a peripheral and a central axon. Central axons severed through DR section or avulsion during brachial plexus injury inefficiently regenerate and do not reenter the spinal cord. We show that a combination of microsurgery and gene therapy circumvented the functional barrier to axonal regrowth at the peripheral and CNS interface. After cervical DR section in rats, microsurgery restored anatomical continuity through a nerve graft that laterally connected the injured DR to an intact DR. Gene transfer to cells in the nerve graft induced the local release of neurotrophin-3 (NT-3) and glial cell line-derived neurotrophic factor (GDNF) and stimulated axonal regrowth. Central DR ganglion axons efficiently regenerated and invaded appropriate areas of the spinal cord dorsal horn, leading to partial recovery of nociception and proprioception. Microsurgery created conditions for functional restoration of DR ganglion central axons, which were improved in combination with gene therapy. This combination treatment provides means to reduce disability due to somatosensory defects after brachial plexus injury.

Results of grafting the anterior and posterior divisions of the upper trunk in complete palsies of the brachial plexus

PURPOSE

In most complete brachial plexus injuries, at least 1 root still is available for grafting. We report on the results obtained with reconstruction of the brachial plexus using short sural nerve grafts that connect nonavulsed roots to the anterior, posterior, or both divisions of the upper trunk.

METHODS

We prospectively studied 22 young adults with complete brachial plexus palsy who had surgical repair an average of 5 months after trauma. Sural nerve grafts connected the C5 root to the anterior division and the C6 root to the posterior division of the upper trunk. When the C6 root was not available, the posterior division of the upper trunk was repaired by means of a nerve transfer. In all cases except one, the suprascapular nerve was repaired via a nerve transfer. Outcomes were assessed an average of 35 months after surgery, focusing on recovery of muscle strength, categorized using the Medical Research Council scale. We compared the results obtained after a single root graft, either C5 (n = 11) or C6 (n = 1), with those observed after double root grafting (i.e., C5 + C6; n = 9). The single case of 3 roots available for grafting was excluded for this comparative study.

RESULTS

With grafting of the anterior division of the upper trunk, 17 of the 22 patients (n = 15) regained useful pectoralis major and biceps function of at least M3. Grafting the anterior and the posterior divisions of the upper trunk resulted in 18 of the 22 patients (n = 18) recovering shoulder abduction-adduction and either elbow flexion or extension. In only 5 cases (5 of 22 patients), however, was shoulder abduction-adduction achieved with concomitant recovery of both elbow flexion and extension. Grafting the posterior division of the upper trunk did not enhance the recovery of shoulder abduction, but it did restore elbow extension in approximately 6 of the 9 patients. In terms of muscle strength, an average of 2.3 muscles scored M3 or M4 in the single-root group, compared with 3.1 in the C5/C6 group (p < .05). The relative probability of recovering elbow flexion and shoulder adduction did not differ between patients with 1 versus 2 root grafts. The results of nerve transfers to the posterior division and of forearm muscle reinnervation were poor.

CONCLUSIONS

Grafting the divisions of the brachial plexus ensured multiple function reconstruction in 18 of the 22 patients (n = 18). However, only 5 of 22 patients (n = 4) experienced restoration of elbow flexion and extension.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Neuroregenerative effects of lentiviral vector-mediated GDNF expression in reimplanted ventral roots

Traumatic avulsion of spinal nerve roots causes complete paralysis of the affected limb. Reimplantation of avulsed roots results in only limited functional recovery in humans, specifically of distal targets. Therefore, root avulsion causes serious and permanent disability. Here, we show in a rat model that lentiviral vector-mediated overexpression of glial cell line-derived neurotrophic factor (GDNF) in reimplanted nerve roots completely prevents motoneuron atrophy after ventral root avulsion and stimulates regeneration of axons into reimplanted roots. However, over the course of 16 weeks neuroma-like structures are formed in the reimplanted roots, and regenerating axons are trapped at sites with high levels of GDNF expression. A high local concentration of GDNF therefore impairs long distance regeneration. These observations show the feasibility of combining neurosurgical repair of avulsed roots with gene-therapeutic approaches. Our data also point to the importance of developing viral vectors that allow regulated expression of neurotrophic factors.