RESUMEN

BACKGROUND: Peripheral nerve injuries remain a major medical problem worldwide and are associated with multiple causes, including gunshot wounds (GSWs), which are the second most common cause of brachial plexus injuries in peacetime and the main, or only, cause reported in wartime studies. The ulnar nerve (UN) is one of the most affected nerves. Peripheral nerve trauma may cause intense neuropathic pain, which is very difficult to control. Particularly UN gunshot injuries may impact individual daily life, as injuries to this nerve result in both sensory and motor deficits within the hand. We evaluated the improvement of neuropathic pain after surgical treatment in a consecutive series of 20 patients with UN injury due to GSWs. METHODS: This single-center, retrospective, consecutive case series included 20 patients with UN injuries due to GSWs, who presented with excruciating neuropathic pain and underwent surgical treatment between 2005 and 2017. RESULTS: Of injuries, 13 occurred in the right upper limb (65%); 12 patients had a high UN injury (60%). Regarding associated injuries, 8 patients had bone injuries (40%), and 4 patients had arterial injuries (20%). A neuroma in continuity was detected in 8 cases (40%), and 4 patients (20%) had shrapnel lodged within the UN. All patients had severe neuropathic pain and functional deficit, with a mean visual analog scale score of 8.45 ± 1.4 and a mean reduction of 6.95 points 12 months after surgery; 10 patients (50%) had a British Medical Research Council score ≥M3. CONCLUSIONS: Surgery is an effective treatment for neuropathic pain from GSWs. Early isolated external neurolysis is associated with better pain management and functional outcomes postoperatively.

Asunto(s)

RESUMEN

This review is intended to describe and actualize the basic knowledge of the three basic entities that affect the peripheral nerve system and can be treated by surgery: nerve trauma, chronic nerve compressions, and tumors.Regarding trauma, emphasis is given on the timing of surgery, given the fact that the moment in which the surgery is performed and the employed microsurgical reconstruction technique are the most important factors in the final result. Open lesions with associated nerve injury should be managed with an early exploration carried out before 7 days. Closed injuries are usually deferred, with few exceptions, from 3 to 6 months after the trauma.In turn, chronic compressions require an appropriate clinical, neurophysiological, and imaging diagnosis. Isolated sensory symptoms can be treated actively though without surgery: motor signs like atrophy should be regarded as a sign for immediate surgery, as a deferred treatment might cause an irreversible nerve and muscular damage. Endoscopic approaches are a valuable tool for treatment in selected neuropathies.Finally, nerve tumors demand a thorough preoperative evaluation, as benign tumors are treated in a very different way when compared to malignant lesions. Benign tumors can usually be safely and completely resected without sacrificing the nerve of origin. When malignancy is confirmed, extensive resection to optimize patient survival is the main objective, potentially at the expense of neurological function. This may then be followed by adjuvant radiation and/or chemotherapy, depending on the nature of the tumor and the completeness of resection attained. The role of nerve biopsy remains controversial, and several modern diagnostic techniques might be helpful.

Asunto(s)

RESUMEN

Cellular senescence and proliferation are essential for wound healing and tissue remodeling. However, senescence-proliferation cell fate after peripheral nerve injury has not been clearly revealed. Here, post-injury gene expression patterns in rat sciatic nerve stumps (SRP113121) and L4-5 dorsal root ganglia (SRP200823) obtained from the National Center for Biotechnology Information were analyzed to decipher cellular senescence and proliferation-associated genetic changes. We first constructed a rat sciatic nerve crush model. Then, ß-galactosidase activities were determined to indicate the existence of cellular senescence in the injured sciatic nerve. Ki67 and EdU immunostaining was performed to indicate cellular proliferation in the injured sciatic nerve. Both cellular senescence and proliferation were less vigorous in the dorsal root ganglia than in sciatic nerve stumps. These results reveal the dynamic changes of injury-induced cellular senescence and proliferation from both genetic and morphological aspects, and thus extend our understanding of the biological processes following peripheral nerve injury. The study was approved by the Animal Ethics Committee of Nantong University, China (approval No. 20190226-001) on February 26, 2019.

RESUMEN

Objective: The aim of this study was to evaluate histopathological, functional and bone densitometry examinations of the beneficial effects of dexpanthenol (DEX) on nerve regeneration in a rat model of peripheral nerve crush injury.Methods: Thirty adult Sprague-Dawley rats were divided equally into three groups. A crush injury was simulated in all rats by clamping the right sciatic nerve for one minute. In group 1, one day before the surgical procedure, 500 mg/kg DEX administered via intraperitoneally (ip) was initiated and continued three times in a week during the experiment period as 28 days. In group 2, rats received a dose of 10 mg/kg DEX to investigate possible effects of DEX alone. Group 3 served as the control (sciatic nerve injury) and was not given any drugs.Results: Performance was significantly lower in group 3 compared to the drug treatment groups during the rotarod test (30 rpm and 40 rpm) (p < 0.05). After a while, the rats which were able to remain on the rod was significantly lower in group 3 during the acceleration test (p < 0.05). Hot plate latency test results in group 3 were significantly lower when compared to the other groups (p < 0.05).Conclusion: DEX appears to be useful as a supportive clinical agent for the treatment of pain and nerve damage.

Asunto(s)

RESUMEN

OBJECTIVE: To assess the indications for and utility of diagnostic ultrasonography (US) in a series of consecutive patients with suspected traumatic peripheral nerve lesions (TPNL). METHODS: We retrospectively reviewed the electronic medical records of consecutive patients referred from February 2013 to May 2018 to our US laboratory. All included patients were examined using standard US equipment, with a 4-13MHz linear array transducer. RESULTS: In the analyzed period, we performed US examinations in 143 patients with 149 suspected TPNL. Electrodiagnostically (EDx) complete TPNL were found in 63 (45%), partial in 59 (42%), and only demyelination (i.e., neurapraxia) in four (3%) patients. TPNL could not be confirmed in 14 (10%) patients. Nerve discontinuity was not demonstrated by US in any of the patients with EDx incomplete nerve lesions. Contact of the nerve with osteosynthetic material (OSM) was found in eight of 33 patients (24%). In five patients, the nerve could not be adequately evaluated throughout its course due to extensive changes in the surrounding tissues. DISCUSSION: In acute situations, US is most useful in EDx complete TPNL to differentiate between nerve axonotmesis and neurotmesis. High-velocity trauma, lacerations, and bone fractures are all risk factors for neurotmesis. In chronic situations, US is useful in cases of functionally inefficient reinnervation, neuropathic pain, or progressive nerve dysfunction. In such patients, the surrounding tissues and the relation of the nerve to any OSM need to be carefully examined. US examination is probably not needed in patients with TPNL following acute blunt trauma, only minor clinical deficits and/or slightly/moderately abnormal EDx findings.

Asunto(s)

RESUMEN

PURPOSE: Functionality of the facial nerve is cosmetically important. While many techniques have been investigated, early and effective treatment for traumatic facial nerve paralysis remains challenging. Here, we aim to examine bacterial cellulose (BC) as a new tubularization material for improving facial nerve regeneration. METHODS: Our study was performed on 40 female Sprague Dawley rats. Rats were randomly divided into four groups, with 10 rats per group. In all rats, the main trunk of the facial nerve was completely cut 8 mm before the branching point. For repairing the facial nerve, in group 1, the nerve was left to recover spontaneously (control group); in group 2, it was repaired by primary suturing (8.0 Ethilon sutures, Ethicon); in group 3, BC tubes alone were used to aid nerve repair; and in group 4, both BC tubes and primary sutures (8.0 Ethilon sutures) were used. After 10 weeks, the facial nerve regeneration was evaluated by the whisker movement test and electrophysiologically (nerve stimulation threshold and compound muscle action potential). Nerve regeneration was assessed by calculating the number of myelinated nerve fibers, and by microscopically evaluating the amount of regeneration and fibrosis. RESULTS: No significant difference was observed among the groups in terms of whisker movement and electrophysiological parameters (P > 0.05). We found that the numbers of regenerating myelinated fibers were significantly increased (P < 0.05) when BC tubes were used as a nerve conduit. CONCLUSIONS: BC can be easily shaped into a hollow tube that guides nerve axons, resulting in better nerve regeneration after transection.

Asunto(s)

RESUMEN

Axonal regeneration and remyelination of peripheral motor neurons (MNs) are critical for restoring neuromuscular motor function after injury or peripheral neuropathy. We examined whether optogenetically mediated light stimulation (OMLS) could enhance the axon outgrowth and myelination of MNs using three-dimensional motor neuron-Schwann cell (MN-SC) coculture on a microfluidic biochip. The biochip was designed to allow SCs to interact with the axons of MNs, while preventing direct contact between SCs and the cell bodies of MNs. Following coculture with SCs on the microfluidic biochip, MNs were transfected with a light-sensitive channelrhodopsin gene. Transfected MNs subjected to repeated light stimulation (20 Hz, 1 hr) produced significantly longer axons than nontransfected MNs. OMLS of MNs greatly increased the number of myelin basic protein (MBP)-expressing SCs, promoting the initiation of myelination of MNs. Ultrastructurally, OMLS of MNs markedly enhanced the thickness of the compact myelin sheath around the MN axons such that the average thickness was closer to that of the theoretical estimates in vivo. Thus, the MN-SC coculture model on a microfluidic biochip augmented by OMLS of MNs is a feasible platform for studying the relationship of neuronal activity with regrowth and remyelination.

Asunto(s)

RESUMEN

INTRODUCTION: We evaluated diagnostic value of sensory tests during recovery from iatrogenic sensory neuropathy using intraoperatively verified nerve injury with subjective symptoms as gold standard. METHODS: Inferior alveolar nerves were monitored neurophysiologically throughout mandibular osteotomy in 19 patients. Sensory disturbance was registered and sensation tested using clinical and quantitative sensory (QST) and neurophysiologic tests postoperatively at 1, 3, 6, and 12 months. Sensitivity, specificity, and predictive values were calculated for all tests. RESULTS: The sensitivity of clinical tests was at best 37%, with 100% specificity, but they lost diagnostic value at chronic stages. Best diagnostic accuracy (highest combination of sensitivity and specificity) at different time points was achieved by combining neurophysiologic and thermal QST or tactile and thermal QST. The single most accurate test was sensory neurography. CONCLUSIONS: Neurography or combinations of neurophysiologic and quantitative tests enables most reliable early and late diagnosis. Clinical sensory examination is inadequate for accurate diagnosis. Muscle Nerve 59:342-347, 2019.

Asunto(s)

RESUMEN

The regenerative potential of the peripheral nervous system (PNS) is widely known, but functional recovery, particularly in humans, is seldom complete. Therefore, it is necessary to resort to strategies that induce or potentiate the PNS regeneration. Our main objective was to test the effectiveness of Olfactory Ensheathing Cells (OEC) transplantation into a biodegradable conduit as a therapeutic strategy to improve the repair outcome after nerve injury. Sciatic nerve transection was performed in C57BL/6 mice; proximal and distal stumps of the nerve were sutured into the collagen conduit. Two groups were analyzed: DMEM (acellular grafts) and OEC (1×105/2µL). Locomotor function was assessed weekly by Sciatic Function Index (SFI) and Global Mobility Test (GMT). After eight weeks the sciatic nerve was dissected for morphological analysis. Our results showed that the OEC group exhibited many clusters of regenerated nerve fibers, a higher number of myelinated fibers and myelin area compared to DMEM group. The G-ratio analysis of the OEC group showed significantly more fibers on the most suitable sciatic nerve G-ratio index. Motor recovery was accelerated in the OEC group. These data provide evidence that the OEC therapy can improve sciatic nerve functional and morphological recovery and can be potentially translated to the clinical setting.

Asunto(s)

RESUMEN

ABSTRACT BACKGROUND AND OBJECTIVES: Considering the scarcity of studies addressing cryotherapy to treat peripheral nervous injuries, this study aimed at evaluating nociception and edema in an experimental sciatic nerve compression model with Wistar rats treated with cryotherapy. METHODS: Forty-two rats were randomly distributed in groups: G1 - control, euthanized in the 15th postoperative day; G2, G3 and G4 - submitted to sciatic nerve compression and euthanized in the 3rd, 8th and 15th postoperative day, respectively; G5, G6 and G7 - submitted to sciatic nerve compression and treated with cryotherapy, euthanized in the 3rd, 8th and 15th postoperative day, respectively. Nociception evaluation at injury site and plantar region, and observation of edema were performed before injury, in the 2nd postoperative day and in the day corresponding to euthanasia of each injured group. Mixed ANOVA was used for statistical analysis, considering significant 5%. RESULTS: There has been decreased pain threshold at injury site in injured groups, however there has been increase in the same groups with regard to evaluations in the 8th and 15th postoperative days. Nociception in the plantar region was similar to previous one, however threshold has not increased. With regard to edema, there has been significant difference in evaluations in the 3rd and 2nd postoperative days corresponding to G1, G4 and G7, which had higher values as compared to pre-injury. CONCLUSION: Cryotherapy has not increased nociceptive threshold or decreased the edema.

RESUMO JUSTIFICATIVA E OBJETIVOS: Considerando a carência de estudos a respeito da crioterapia como tratamento de lesão nervosa periférica, este estudo teve como objetivo avaliar a nocicepção e o edema em modelo experimental de compressão do nervo isquiático em ratos Wistar, tratados com crioterapia. MÉTODOS: Foram utilizados 42 ratos separados aleatoriamente nos grupos: G1 - controle, eutanasiado no 15º de pós-operatório; G2, G3 e G4 - submetidos à compressão do nervo isquiático, eutanasiados no 3º, 8º e 15º de pós-operatório, respectivamente; G5, G6 e G7 - submetidos à compressão do nervo isquiático e tratados com crioterapia, eutanasiados no 3º, 8º e 15º de pós-operatório, respectivamente. As avaliações da nocicepção no local da lesão e na região plantar, e a verificação do edema aconteceram nos momentos pré-lesão, 2º dia de pós-operatório e no dia correspondente a eutanásia de cada grupo lesionado. A análise estatística foi pela ANOVA mista, com nível de significância de 5%. RESULTADOS: No local da lesão houve diminuição do limiar doloroso nos grupos lesionados, entretanto, apresentou aumento do mesmo nos grupos relacionados às avaliações do 8º e 15º de pós-operatório. Já a nocicepção realizada na região plantar foi semelhante à anterior, porém o limar não aumentou. Com relação ao edema, houve diferença significativa na avaliação realizada no 3º e no 2º dias de pós-operatório correspondentes ao G1, G4 e G7, que apresentaram valores maiores comparadas com a pré-lesão. CONCLUSÃO: A crioterapia não auxiliou no aumento do limiar nociceptivo e redução de edema.

RESUMEN

INTRODUCTION: Peripheral nerve injuries (PNI) sustained in combat are typically severe and are frequently associated with marked soft tissue damage, anatomic distortion, and retained metallic fragments. These features complicate clinical and electrodiagnostic assessment and may preclude MRI. METHODS: We describe 4 cases of military personnel who sustained high-velocity gunshot wounds or blasts with metal fragment injuries in which high resolution peripheral nerve ultrasound (US) proved beneficial. RESULTS: In these cases, the clinical and electrodiagnostic exams provided inadequate localization and severity data of the nerve injuries, and MRI was either precluded or provided no additional information. In each case, US disclosed focal nerve segment abnormalities, including regions of focal enlargement and nerve discontinuity with end-bulb neuroma, which guided surgical planning for nerve repair. The findings on US were subsequently confirmed intra-operatively. CONCLUSIONS: High resolution peripheral nerve US is a useful modality in assessment of combat-related PNI. Muscle Nerve, 2016 Muscle Nerve 54: 1139-1144, 2016.

Asunto(s)

RESUMEN

OBJECTIVE: traumatic neuroma is a pathological condition of peripheral nervous system consisting of localized proliferation of injured nerve elements. The symptoms depend on the type of involved nerve (motor and/or sensitive) and on the site and the extension of the lesion. Ultrasound is the best tool to depict the morphology of nerve, especially in traumatic conditions. We present a study aimed to assess the correlation between the degree of nerve function and the ultrasound morphology of neuromas. PATIENTS AND METHODS: we retrospectively evaluated 18 patients with neuromas (not transected) occurred after a closed nerve trauma evaluated with clinical and ultrasound assessment. The clinical evaluation was related to the % of increase of cross sectional area as detected by nerve ultrasound respect to normal nerve. RESULTS: we observed that dimensions of neuromas are not related to function until neuroma have cross sectional area 5 times enlarged respect to normal nerve, in this case recovery never occurs. CONCLUSION: our study failed to clear detect a relation between cross sectional area enlargement of neuroma and nerve function, but showed a cut off beyond which prognosis is negative. This result provide some useful information for prognosis, nevertheless we believe that future perspective studies are needed to better understand the timing of developing neuromas and its evolution.

Asunto(s)

RESUMEN

Successful management of peripheral nerve trauma relies on accurate localization of the injury and grading of the severity of nerve injury to determine whether surgical intervention is required. Existing techniques, such as electrodiagnostic studies and conventional imaging modalities, provide important information, but are limited by being unable to distinguish severe nerve lesions in continuity that will recover from those that will not. Diffusion tensor imaging (DTI) and tractography of peripheral nerves provide a novel technique to localize and grade nerve injury, by assessing the integrity of the nerve fibers across the site of nerve injury. Diffusion tensor imaging and tractography also hold promise as markers of early nerve regeneration, prior to clinical and electrodiagnostic evidence of recovery. In the present review, the techniques of peripheral nerve DTI and tractography are discussed with respect to peripheral nerve trauma, with illustrative cases demonstrating potential roles of these novel approaches.

Asunto(s)

RESUMEN

INTRODUCTION: At least 25% of knee dislocations are associated with common fibular nerve injury. Diagnosis is usually based on clinical and neurophysiological findings. We assessed the role of nerve ultrasound in common fibular nerve injury. METHODS: Eight consecutive patients (6 men and 2 women, mean age 34 years) with knee luxation referred to our laboratory underwent clinical, neurophysiological, and ultrasound examination. RESULTS: In all patients we observed a similar pattern: severe weakness (plegia or severe paresis); neurophysiological involvement of both fibular nerve branches; and ultrasound evidence of increased fibular nerve area with hypoechogenicity. On follow-up evaluation, 6 patients remained stable, and 2 patients improved. The greater the ultrasound fibular nerve enlargement, the worse the recovery. CONCLUSIONS: Nerve ultrasound was confirmed to be a useful diagnostic/prognostic tool in traumatic nerve lesions. A prompt ultrasound examination of the fibular nerve should be considered after any case of knee dislocation.

Asunto(s)

RESUMEN

Peripheral nerve surgery represents a broad field of pathologic conditions, medical specialties, and anatomic regions of the body. Anatomic understanding of hierarchical nerve structure and the peripheral nervous system aids diagnosis and management of nerve lesions. Many peripheral nerves coalesce into organized arrays, including the cervical, brachial, and lumbosacral plexuses, controlling motor and sensory functions of the trunk and extremities. Individual or groups of nerves may be affected by various pathologic conditions, including trauma, entrapment, tumor, or iatrogenic damage. Current research efforts focus on enhancing the peripheral nerve regenerative process by targeting Schwann cells, nerve growth factors, and nerve allografts.

Asunto(s)