Evaluation of Rehabilitation Techniques for Traumatic Ulnar Nerve Injuries After Surgical Repair: A Systematic Review.

BACKGROUND: Traumatic ulnar nerve injuries often result in significant loss of motor and sensory function, negatively impacting patients' quality of life. Physical rehabilitation is crucial for recovery, but standardized treatment protocols are lacking. This study aims to systematically review rehabilitation techniques to identify future research direction and improve existing protocols for ulnar nerve injury patients. METHODS: PubMed, Embase, CINAHL, Cochrane CENTRAL, Web of Science, and Scopus were queried from inception until July 31, 2023. Articles containing axonotmesis or neurotmesis injuries of the ulnar nerve were included. Reviews, opinions, editorials, technical reports without clinical outcomes, conference abstracts, non-English text, nonhuman studies, and studies without adult patients were excluded. Three independent reviewers performed screening and data extraction using Covidence, and risk of bias assessments utilizing Cochrane and JBI tools. Because of article heterogeneity, a narrative review was conducted. The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database, registration number CRD42023442016. RESULTS: This systematic review included one randomized controlled trial and four observational studies (103 patients), which exhibited differences in study quality. Overall, motor and sensory outcomes improved after rehabilitation. Rehabilitation techniques varied widely, and early sensory reeducation appeared to improve sensory function. Only two studies included patient-reported outcomes. CONCLUSIONS: Diverse rehabilitation techniques are used to address ulnar nerve injuries. The low number of included studies, differences in study quality, and small sample size underscore the need for larger and more inclusive studies to improve functional recovery after ulnar nerve injuries. Future research should consider the impact of patient and injury characteristics to develop comprehensive treatment guidelines for these patients.

[Peripheral nerves' function recovery by intratissual electric stimulation]. / Vosstanovlenie funktsii perifericheskikh nervov vnutritkanevoi elektrostimulyatsiei.

An intratissual electrical stimulation, accompanied by irritation of their central neurons, is used to recover the function of damaged peripheral nerves. Treatment results exceeded those with the use of cutaneous electrical stimulation, which is confirmed by comparative results of trial animal experiments. The time and quality of peripheral nerves' function recovery in comparison of intratissual and cutaneous electrical stimulation methods remain unknown. OBJECTIVE: To evaluate the time and quality of peripheral nerves' functions recovery after their suturing and conducting two different methods of electrical stimulation, namely intratissual and cutaneous, in projection of central neurons of damaged spinal nerves in the postoperative period. MATERIAL AND METHODS: The basic technical parameters of the method of peripheral nerves' functions recovery in the postoperative period were ptacticed. Postoperative rehabilitation treatment was performed in 77 patients with traumatic peripheral nerves' injuries at the level of the forearm: in 42 with intratissual electrical stimulation, in 35 - using cutaneous one with similar characteristics of electrical current and concomitant pharmacological therapy. The follow-up duration was 2 years. RESULTS: A significant (in 4-6 times) reduction in time of treatment and a greater improvement in qualitative indicators when using intratissual electrical stimulation compared to the use of cutaneous stimulation were obtained. The effectiveness of the restorative therapy was dependent on the number of procedures, and a complete recovery of the damaged peripheral nerves' functions was observed after three courses of intratissual electrical stimulation. CONCLUSION: The time and degree of recovery of peripheral nerves' functions depends on the functional activity of their central neurons at the level of the spinal cord. The activation of these neurons by low-frequency electrical current allows to activate their trophic function. Thus, the cutaneous electrical stimulation does not cause the necessary level of irritation of the neurons due to the fact that the skin is a barrier to electrical current, which reduces its impact in 200-500 times. The intratissual electrical stimulation allows to solve the problem by supplying the needle-electrode much closer to the «target¼. The proposed method of intratissual electrical stimulation has shown its advantage over cutaneous electrical stimulation, significantly reducing the duration of the restorative treatment and increasing its qualitative indicators.

Motoneuron activity is required for enhancements in functional recovery after peripheral nerve injury in exercised female mice.

Inhibitory luminopsins (iLMO2) integrate opto- and chemo-genetic approaches and allow for cell-type specific inhibition of neuronal activity. When exposed to a Renilla luciferase substrate, Coelenterazine (CTZ), iLMO2 generates bioluminescence-mediated activation of its amino-terminal halorhodopsin, resulting in neuronal inhibition. Moderate daily exercise in the form of interval treadmill-training (IT) applied following a peripheral nerve injury results in enhanced motor axon regeneration and muscle fiber reinnervation in female mice. We hypothesized that iLMO2 mediated inhibition of motoneuron activity during IT would block this enhancement. Unilateral intramuscular injections of Cre-dependent AAV2/9-EF1a-DIO-iLMO2 (∼8.5 x 1013 vg/ml) were made into the gastrocnemius and tibialis anterior muscles of young female ChAT-IRES-Cre mice, thereby limiting iLMO2 expression specifically to their motoneurons. Four to six weeks were allowed for retrograde viral transduction after which a unilateral sciatic nerve transection (Tx) and repair was performed. Animals were randomized into four groups: IT only, IT + CTZ, CTZ only, and untreated (UT). Three weeks post Tx-repair, the maximal amplitude direct muscle responses (M-max) in both muscles in the IT only group were significantly greater than in UT mice, consistent with the enhancing effects of this exercise regimen. Inhibiting motoneuron activity during exercise by a single injection of CTZ, administered 30 minutes prior to exercise, completely blocked the enhancing effect of exercise. Similar treatments with CTZ in mice without iLMO2 had no effect on regeneration. Neuronal activity is required for successful enhancement of motor axon regeneration by exercise.

Cold intolerance and neuropathic pain after peripheral nerve injury in upper extremity.

Cold intolerance and pain can be a substantial problem in patients with peripheral nerve injury. We aimed at investigating the relationships among sensory recovery, cold intolerance, and neuropathic pain in patients affected by upper limb peripheral nerve injury (Sunderland type V) treated with microsurgical repair, followed by early sensory re-education. In a cross-sectional clinical study, 100 patients (male/female 81/19; age 40.5 ± 14.8 years and follow-up 17 ± 5 months, mean ± SD), with microsurgical nerve repair and reconstruction in the upper extremity and subsequent early sensory re-education, were evaluated, using Cold Intolerance Symptoms Severity questionnaire-Italian version (CISS-it, cut-off pathology >30/100 points), CISS questionnaire-12 item version (CISS-12, 0-46 points-grouping: healthy that means no cold intolerance [0-14], mild [15-24], moderate [25-34], severe [35-42], very severe [43-46] cold intolerance), probability of neuropathic pain (DouleurNeuropathique-4; [DN4] 4/10), deep and superficial sensibility, tactile threshold (monofilaments), and two-point discrimination (cutoff S2; Medical Research Council scale for sensory function; [MRC-scale]). A high CISS score is associated with possible neuropathic pain (DN4 ≥ 4). Both a low CISS-it score (ie, < 30) and DN4 < 4 is associated with good sensory recovery (MRC ≥ 2). In conclusion patients affected by upper limb peripheral nerve injuries with higher CISS scores more often suffer from cold intolerance and neuropathic pain, and the better their sensory recovery is, the less likely they are to suffer from cold intolerance and neuropathic pain.

Enhancing function after radial nerve injury with a high-profile orthosis and a bio-occupational orthotic framework.

STUDY DESIGN: Case report. INTRODUCTION: Radial nerve injury can cause severe functional impairment due to paralysis of wrist and digit extensors. Various orthotic designs have been described, including static, dynamic, and tenodesis. All provide wrist stabilization or extension assistance. Some, but not all, also provide extension assistance to the wrist, thumb, and fingers. PURPOSE AND METHODS: This article tells the story of Max, a 27-year-old male university student, who sustained a radial nerve injury after a left humeral shaft fracture. He was treated at a Brazilian tertiary hospital, where the choice of thermoplastics and dynamic components resulted in limited options for orthotic fabrication. Max was provided with custom-molded static wrist orthosis and a bulky, older style, high-profile dynamic forearm-based wrist-finger-thumb assistive-extension orthosis. RESULTS AND DISCUSSION: Grip strength and functional status improved, and Max was completely satisfied because with the dynamic orthosis, he could play the guitar again, which was his favorite activity. CONCLUSION: Max's story illustrates that a convenient functionally oriented orthotic intervention can be performed even in resource-limited environments by following the client-centered bio-occupational orthotic framework proposed by McKee and Rivard. This framework addresses the client's biological needs (addressing paralyzed muscles and maintaining length of soft tissues) and occupational/functional needs.

Calotropis procera (root) escalates functions rehabilitation and attenuates oxidative stress in a mouse model of peripheral nerve injury.

Peripheral nerve injuries result in sensorimotor functional loss, leading to permanent disability and physical dependency with immense cost and reduced quality of life. These injuries are among those complicated medical situations which still are waiting for their first-line treatment. This study was designed to investigate the role of Calotropis procera (crude roots) in accelerating functional retrieval following mechanically induced sciatic nerve injury in healthy albino male mice. Following acclimatization, mice were grouped equally as "Control" fed on normal chow and "Root" fed on C. procera root (100mg/kg/day) mixed chow. A mechanical crush was induced in right sciatic nerve of animals. Behavioral analyses (grip strength, SFI, pinprick and hot plate tests) were conducted for assessing sensorimotor function reclamation and blood was collected for oxidative stress assessment. Significantly earlier retrieval of sensorimotor activities (p<0.05), reduced total oxidant status, increased total antioxidant capacity with prominently enhanced arylesterase and paraoxonase activities (p<0.001) in treatment group suggested positive impact of C. procera roots on quickening functional recovery and combating oxidative stress following nerve injury. Thus C. procera root can be considered as potential candidate drug for further investigation to seek bioactive compound/s that may actually responsible for ameliorative functional recovery following nerve injury.

A Touch-Observation and Task-Based Mirror Therapy Protocol to Improve Sensorimotor Control and Functional Capability of Hands for Patients With Peripheral Nerve Injury.

IMPORTANCE: To develop a practical program in the early phase after nerve repair for more rapid return of function. OBJECTIVE: To investigate the effects of touch-observation and task-based mirror therapy on the sensorimotor outcomes of patients with nerve repair. DESIGN: An assessor-blinded study with a randomized controlled design. SETTING: University hospital. PARTICIPANTS: We recruited 12 patients with median or ulnar nerve repair between the level of midpalm and elbow referred by the plastic surgeons. INTERVENTION: The patients were randomized into touch-observation and task-based mirror therapy or control groups, and both groups received training for 12 wk. OUTCOMES AND MEASURES: The Semmes-Weinstein monofilament (SWM) test, two-point discrimination test, Purdue Pegboard Test (PPT), Minnesota Manual Dexterity Test (MMDT), and pinch-holding-up activity test were assessed at pretreatment, immediately after treatment, and 12 wk after the last treatment. RESULTS: The experimental group showed greater improvements in the results of the pinch-holding-up activity test and the PPT Unilateral Pin Insertion, Bilateral Pin Insertion, and Assembly subtests. However, change on the SWM test revealed no significant difference between the two groups. CONCLUSIONS AND RELEVANCE: Touch-observation and task-based mirror therapy is an effective but low-cost treatment protocol to optimize sensorimotor control and functional capability of the upper limb in patients with peripheral nerve injury.

Luxatio erecta humeri with humeral greater tuberosity fracture and axillary nerve injury.

Luxatio erecta humeri is the rarest type of glenohumeral dislocation, which has been reported to be associated with humeral fracture, rotator cuff tear and neurovascular injury. To our knowledge, a single-sided acute inferior glenohumeral dislocation associated with humeral greater tuberosity fracture and axillary nerve injury has not yet been reported. Here, we reported a traumatic first-time inferior shoulder dislocation from a construction worker who got hyperflexion of the left shoulder when fell and grasped the railing causing. The patient underwent traction counter-traction closed reduction followed by proper immobilization, and rehabilitation therapy. At thirteen months follow-up, the patient had returned to the workload that required high stress on shoulder joint with an excellent outcome.

Femoral Nerve Palsy Following Total Hip Arthroplasty: Incidence and Course of Recovery.

BACKGROUND: Femoral nerve palsy (FNP) is a relatively uncommon complication following total hip arthroplasty (THA). There is little recent literature regarding the incidence of FNP and the natural course of recovery. METHODS: Using our institutional database, we identified postoperative FNPs from 17,350 consecutive primary THAs performed from 2011 to 2016. Hip exposures were performed using a direct lateral (modified Hardinge), direct anterior (Smith-Peterson), anterolateral (Watson-Jones), or posterolateral (Southern or Moore) approach. Patients with FNP were contacted to provide a subjective assessment of convalescence and underwent objective muscle testing to determine the extent of motor recovery. RESULTS: The overall incidence of FNP was 0.21% after THA, with the incidence 14.8-fold higher in patients undergoing anterior hip surgery using either a direct anterior (0.40%) or anterolateral (0.64%) approach. Significant recovery from FNP did not commence for a majority of patients until greater than 6 months postoperatively. Motor weakness had resolved in 75% of patients at 33.3 months, with remaining patients suffering from mild residual weakness that typically did not necessitate an assistive walking device or a knee brace. Nearly all patients had improved sensory manifestations, but such symptoms had completely resolved in less than 20% of patients. CONCLUSION: FNP after hip surgery remains relatively uncommon, but may increase with a growing interest in anterior THA exposures. A near complete recovery with only mild motor deficits can be expected for a majority of patients in less than 2 years, although sensory symptoms may persist.

Electromyographic Biofeedback in Motor Function Recovery After Peripheral Nerve Injury: An Integrative Review of the Literature.

Electromyographic biofeedback (EMG-BF) has been applied to treat different types of peripheral nerve injuries (PNI). However, despite the clinical practice widespread use its evidence is controversial. With the objective of summarize the available evidence on the electromyographic biofeedback effectiveness and efficacy to help motor function recovery after PNI an integrative review was performed. A secondary objective was to identify the conceptual framework and strategies of EMG-BF intervention, and the quality of technical description of EMG-BF procedures. To conduct this integrative review a systematic search of the literature was performed between October 2013 and July 2018, in PUBMED, ISI and COCHRANE databases for EMG-BF original studies in PNI patients of any etiology, in English, Portuguese, Spanish or French, published after 1990. Exclusion criteria were poor description of EMG-BF treatment, associated treatment that could impair EMG-BF effect, inclusion of non-PNI individuals and case studies design. The PEDro scale was used to evaluate study quality of randomized clinical trials (RCTs) included. This resulted in 71 potential articles enrolled to full reading, although only nine matched the inclusion criteria. PNI included facial paralysis, acute sciatic inflammation and carpal tunnel syndrome. The average quality score of the included RCTs was five, corresponding to low methodological quality. Due to the small number of included articles, low quality studies and heterogeneity of interventions, outcomes and population we concluded that there is limited evidence of EMG-BF effectiveness and efficacy for motor function recovery in PNI patients.

Patients' views on early sensory relearning following nerve repair-a Q-methodology study.

STUDY DESIGN: Descriptive study. INTRODUCTION: Early sensory relearning where the dynamic capacity of the brain is used has been shown to improve sensory outcome after nerve repair. However, no previous studies have examined how patients experience early sensory relearning. PURPOSE OF THE STUDY: To describe patient's views on early sensory relearning. METHODS: Statements' scores were analyzed by factor analysis. RESULTS: Thirty-seven consecutive adult patients with median and/or ulnar nerve repair who completed early sensory relearning were included. Three factors were identified, explaining 45% of the variance: (1) "Believe sensory relearning is meaningful, manage to get an illusion of touch and complete the sensory relearning"; (2) "Do not get an illusion of touch easily and need support in their sensory relearning" (3) "Are not motivated, manage to get an illusion of touch but do not complete sensory relearning". DISCUSSION: Many patients succeed in implementing their sensory relearning. However, a substantial part of the patient population need more support, have difficulties to create illusion of touch, and lack motivation to complete the sensory relearning. To enhance motivation and meaningfulness by relating the training clearly to everyday occupations and to the patient's life situation is a suggested way to proceed. CONCLUSION: The three unique factors indicate motivation and sense of meaningfulness as key components which should be taken into consideration in developing programs for person-centered early sensory relearning. LEVEL OF EVIDENCE: 3.

[Research Progress on Function Evaluation Standard and Method of Lower Extremity Impairment].

The lower extremity impairment can be caused by illness, accident, work-related injury, traffic accident and fighting, etc. The injuries of lower extremity joint, nerve, muscle and tendon may lead to lower extremity dysfunction. So far, there is no unified standard for international and domestic function evaluation of lower extremity impairment, the evaluation standards in the same field are also different, and function evaluation of lower extremity impairment has no complete research system. However, the degree of lower extremity impairment has great influence on personal damage compensation. Therefore, the function evaluation of lower extremity impairment often becomes a dispute issue in forensic medicine identification. This article summarizes the function evaluation standards, methods and status quo of lower extremity impairment, so as to provide a new insight into the research on standardization of lower extremity impairment.

Effects of forced, passive, and voluntary exercise on spinal motoneurons changes after peripheral nerve injury.

After peripheral nerve injury, there are important changes at the spinal level that can lead to disorganization of the central circuitry and thus compromise functional recovery even if axons are able to successfully regenerate and reinnervate their target organs. Physical rehabilitation is a promising strategy to modulate these plastic changes and thus to improve functional recovery after the damage of the nervous system. Forced exercise in a treadmill is able to partially reverse the synaptic stripping and the loss of perineuronal nets that motoneurons suffer after peripheral nerve injury in animal models. The aim of this study was to investigate whether passive exercise, by means of cycling in a motorized bicycle, or voluntary free running in a wheel is able to mimic the effects induced by forced exercise on the changes that axotomized motoneurons suffer after peripheral nerve injury. Partial preservation of synapses and perineuronal nets was observed only in axotomized motoneurons from animals subjected to high-intensity cycling and the ones that freely ran long distances, but not when low-intensity exercise protocols were applied. Therefore, the intensity but not the type of exercise used is the key element to prevent synaptic stripping and loss of perineuronal nets in motoneurons after axotomy.

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.

Upslope treadmill exercise enhances motor axon regeneration but not functional recovery following peripheral nerve injury.

Following peripheral nerve injury, moderate daily exercise conducted on a level treadmill results in enhanced axon regeneration and modest improvements in functional recovery. If the exercise is conducted on an upwardly inclined treadmill, even more motor axons regenerate successfully and reinnervate muscle targets. Whether this increased motor axon regeneration also results in greater improvement in functional recovery from sciatic nerve injury was studied. Axon regeneration and muscle reinnervation were studied in Lewis rats over an 11 wk postinjury period using stimulus evoked electromyographic (EMG) responses in the soleus muscle of awake animals. Motor axon regeneration and muscle reinnervation were enhanced in slope-trained rats. Direct muscle (M) responses reappeared faster in slope-trained animals than in other groups and ultimately were larger than untreated animals. The amplitude of monosynaptic H reflexes recorded from slope-trained rats remained significantly smaller than all other groups of animals for the duration of the study. The restoration of the amplitude and pattern of locomotor EMG activity in soleus and tibialis anterior and of hindblimb kinematics was studied during treadmill walking on different slopes. Slope-trained rats did not recover the ability to modulate the intensity of locomotor EMG activity with slope. Patterned EMG activity in flexor and extensor muscles was not noted in slope-trained rats. Neither hindblimb length nor limb orientation during level, upslope, or downslope walking was restored in slope-trained rats. Slope training enhanced motor axon regeneration but did not improve functional recovery following sciatic nerve transection and repair.

The topographic specificity of muscle reinnervation predicts function.

Functional testing has assumed a progressively dominant role in validating the success of experimental nerve repair. Results obtained in one model, however, cannot predict the results in others because they reflect the coordinated interaction of several muscles across multiple joints. As a result, many combinations of topographically correct and incorrect muscle reinnervation could produce the same result. We have developed a binary model in which elbow flexors and extensors are reinnervated, and elbow flexion and extension are the functions tested. The musculocutaneous and radial nerves of Lister-Hooded rats were subjected to axonotmetic injuries that produced increasing degrees of axonal misdirection at the site of injury ranging from simple crush to transection and rotational offset of proximal and distal stumps. Elbow function was tested with a device that requires coordinated elbow extension to reach sugar pellets and flexion to return them to the mouth. After 12 weeks of regeneration, motoneurons projecting to the distal musculocutaneous nerve were retrogradely labelled with WGA-Ruby and scored regarding their location within musculocutaneous or radial motoneuron pools. The severity of axonal misdirection resulting from the initial surgery was mirrored by progressive degrees of inappropriate reinnervation of the musculocutaneous nerve by radial nerve axons. The specificity of reinnervation predicted elbow function (r = 0.72), whereas the number of motoneurons regenerating did not. This model is thus well suited to study the interaction of regeneration specificity and function across a single joint, and to produce data that can be generalized more broadly than those obtained from more complex models.

Functional evaluation of peripheral nerve regeneration and target reinnervation in animal models: a critical overview.

Peripheral nerve injuries usually lead to severe loss of motor, sensory and autonomic functions in the patients. Due to the complex requirements for adequate axonal regeneration, functional recovery is often poorly achieved. Experimental models are useful to investigate the mechanisms related to axonal regeneration and tissue reinnervation, and to test new therapeutic strategies to improve functional recovery. Therefore, objective and reliable evaluation methods should be applied for the assessment of regeneration and function restitution after nerve injury in animal models. This review gives an overview of the most useful methods to assess nerve regeneration, target reinnervation and recovery of complex sensory and motor functions, their values and limitations. The selection of methods has to be adequate to the main objective of the research study, either enhancement of axonal regeneration, improving regeneration and reinnervation of target organs by different types of nerve fibres, or increasing recovery of complex sensory and motor functions. It is generally recommended to use more than one functional method for each purpose, and also to perform morphological studies of the injured nerve and the reinnervated targets.

Lack of motor recovery after prolonged denervation of the neuromuscular junction is not due to regenerative failure.

Motor axons in peripheral nerves have the capacity to regenerate after injury. However, full functional motor recovery rarely occurs clinically, and this depends on the nature and location of the injury. Recent preclinical findings suggest that there may be a time after nerve injury where, while regrowth to the muscle successfully occurs, there is nevertheless a failure to re-establish motor function, suggesting a possible critical period for synapse reformation. We have now examined the temporal and anatomical determinants for the re-establishment of motor function after prolonged neuromuscular junction (NMJ) denervation in rats and mice. Using both sciatic transection-resuture and multiple nerve crush models in rats and mice to produce prolonged delays in reinnervation, we show that regenerating fibres reach motor endplates and anatomically fully reform the NMJ even after extended periods of denervation. However, in spite of this remarkably successful anatomical regeneration, after 1 month of denervation there is a consistent failure to re-establish functional recovery, as assessed by behavioural and electrophysiological assays. We conclude that this represents a failure in re-establishment of synaptic function, and the possible mechanisms responsible are discussed, as are their clinical implications.

Persistent alterations in active and passive electrical membrane properties of regenerated nerve fibers of man and mice.

Excitability of regenerated fibers remains impaired due to changes in both passive cable properties and alterations in the voltage-dependent membrane function. These abnormalities were studied by mathematical modeling in human regenerated nerves and experimental studies in mice. In three adult male patients with surgically repaired complete injuries of peripheral nerves of the arm 22 months-26 years prior to investigation, deviation of excitability measures was explained by a hyperpolarizing shift in the resting membrane potential and an increase in the passive 'Barrett and Barrett' conductance (GBB) bridging the nodal and internodal compartments. These changes were associated with an increase in the 'fast' K(+) conductance and the inward rectifier conductance (GH). Similar changes were found in regenerated mouse tibial motor axons at 1 month after a sciatic crush lesion. During the first 5 months of regeneration, GH showed partial recovery, which paralleled that in GBB. The internodal length remained one-third of normal. Excitability abnormalities could be reversed by the energy-dependent Na(+)/K(+) pump blocker ouabain resulting in membrane depolarization. Stressing the Na(+) pumping system during a strenuous activity protocol triggered partial Wallerian degeneration in regenerated nerves but not in control nerves from age-matched mice. The current data suggest that the nodal voltage-gated ion channel machinery is restored in regenerated axons, although the electrical separation from the internodal compartment remains compromised. Due to the persistent increase in number of nodes, the increased activity-dependent Na(+) influx could lead to hyperactivity of the Na(+)/K(+) pump resulting in membrane hyperpolarization and neurotoxic energy insufficiency during strenuous activity.

Nerve transfers and neurotization in peripheral nerve injury, from surgery to rehabilitation.

Peripheral nerve injury (PNI) and recent advances in nerve reconstruction (such as neurotization with nerve transfers) have improved outcomes for patients suffering peripheral nerve trauma. The purpose of this paper is to bridge the gap between the electromyographer/clinical neurophysiologist and the peripheral nerve surgeon. Whereas the preceding literature focuses on either the basic science behind nerve injury and reconstruction, or the surgical options and algorithms, this paper demonstrates how electromyography is not just a 'decision tool' when deciding whether to operate but is also essential to all phases of PNI management including surgery and rehabilitation. The recent advances in the reconstruction and rehabilitation of PNI is demonstrated using case examples to assist the electromyographer to understand modern surgical techniques and the unique demands they ask from electrodiagnostic testing.