Neurotropin® accelerates peripheral nerve regeneration in a rat sciatic nerve crush injury model

BACKGROUND

Peripheral nerve injuries are common and serious conditions. The effect of Neurotropin® (NTP), a nonprotein extract derived from the inflamed skin of rabbits inoculated with vaccinia virus, on peripheral nerve regeneration has not been fully elucidated. However, it has analgesic properties via the activation of descending pain inhibitory systems. Therefore, the current study aimed to determine the effects of NTP on peripheral nerve regeneration.

METHODS

We examined axonal outgrowth of dorsal root ganglion (DRG) neurons using immunocytochemistry in vitro. In addition, nerve regeneration was evaluated functionally, electrophysiologically, and histologically in a rat sciatic nerve crush injury model in vivo. Furthermore, gene expression of neurotrophic factors in the injured sciatic nerves and DRGs was evaluated.

RESULTS

In the dorsal root ganglion neurons in vitro, NTP promoted axonal outgrowth at a concentration of 10 mNU/mL. Moreover, the systemic administration of NTP contributed to the recovery of motor and sensory function at 2 weeks, and of sensory function, nerve conduction velocity, terminal latency, and axon-remyelination 4 weeks after sciatic nerve injury. In the gene expression assessment, insulin-like growth factor 1 and vascular endothelial growth factor expressions were increased in the injured sciatic nerve 2 days postoperatively.

CONCLUSIONS

Therefore, NTP might be effective in not only treating chronic pain but also promoting peripheral nerve regeneration after injury.

Progress and mechanism of graphene oxide-composited materials in application of peripheral nerve repair

Peripheral nerve injuries (PNI) are one of the most common nerve injuries, and graphene oxide (GO) has demonstrated significant potential in the treatment of PNI. GO could enhance the proliferation, adhesion, migration, and differentiation of neuronal cells by upregulating the expression of relevant proteins, and regulate the angiogenesis process and immune response. Therefore, GO is a suitable additional component for fabricating artificial nerve scaffolds (ANS), in which the slight addition of GO could improve the physicochemical performance of the matrix materials, through hydrogen bonds and electrostatic attraction. GO-composited ANS can increase the expression of nerve regeneration-associated genes and factors, promoting angiogenesis by activating the RAS/MAPK and AKT-eNOS-VEGF signaling pathway, respectively. Moreover, GO could be metabolized and excreted from the body through the pathway of peroxidase degradation in vivo. Consequently, the application of GO in PNI regeneration exhibits significant potential for transitioning from laboratory research to clinical use.

The role of preoperative ultrasound in the management of peripheral nerve injuries

BACKGROUND

Peripheral nerve injury refers to any damage or trauma to the nerves located outside the central nervous system. Ultrasonography is a reliable, cheap, and minimally invasive method in clinical practice to give physicians useful information about nerve injury.

OBJECTIVES

to assess the power of ultrasound in determining the presence, localization, and extent of neural damage in patients with clinical evidence of peripheral nerve lesions before surgery.

METHODS

This cross-sectional study was conducted on 78 patients (56 females and 22 males, aged from 9 to 52 years) who had different pathologies including entrapment, tumoral, post-traumatic, and post-surgical nerve injuries at the Neurosurgery and Physical Medicine, Rheumatology, and Rehabilitation Departments, Tanta University Hospitals. All studied patients had preoperative evaluation; neurological examination, electrodiagnostic studies, and sonographic examinations with linear array transducers (frequencies ranging from 7.5 to 16 MHz).

RESULTS

The most common pathological condition was entrapment neuropathy (39 patients) (50%). Ultrasound complemented the electrodiagnostic studies by determining the site of entrapment manifested by increased mean maximum cross-sectional area of the nerve proximal to the site of entrapment and nerve hypoechogenicity. In post-traumatic and iatrogenic neuropathies (35 patients) (44.9%), the ultrasound finding revealed neuroma in continuity in nine cases (11.5%), complete neurotmesis with stump neuroma in eighteen patients (23.1%), and eight cases (10.3%) showed perineural adhesion. In all cases, the nerve was hypoechoic at the site of injury. The presence of hyperechoic fibrous tissue could indicate perineural adhesion and the necessity for neurolysis. This study also included three (3.8%) cases had schwannoma, and one case (1.3%) had neurofibroma. Ultrasound was used to confirm the diagnosis by determining the tumor's size and vascular supply.

CONCLUSIONS

Ultrasonography is a diagnostic and surgical planning tool that is becoming more and more useful for the management of peripheral nerve injuries. Its high resolution and real-time capability provide safe and cost-effective scans that aid in determining the extent of injuries. For patients with peripheral nerve injuries, ultrasound is advised to be added to the routine clinical and neurophysiological evaluation. It is also advised to use ultrasound as a first-line imaging modality for tumors thought to be of nerve origin.

Digital nerve injury: to repair or not?

BACKGROUND

There are very few studies comparing patients with and without repair after digital nerve injury. It is still controversial whether digital nerve repair is necessary.

AIMS

The aim of this study was to evaluate the long-term clinical outcomes of patients with unilateral isolated digital nerve injury who underwent surgical repair and those who did not.

METHODS

Seventy-four patients with unilateral digital nerve injury were included in the study. Of these, the patients who underwent surgical repair were determined as group A (n = 42), the patients without repair as group B (n = 32), and the groups were divided into subgroups according to injury levels. Results were evaluated with a minimum follow-up of 24 months.

RESULTS

When the S2PD results were evaluated overall, it was found that those who had digital nerve repair (group A) had significantly better outcomes compared to those without repair (group B) (p = 0.012). When the subgroups were evaluated according to the injury localization, no significant difference was observed at the distal levels, while it was observed that the patients who underwent repair in the proximal levels showed significantly better results (p = 0.003, p = 0.012).

CONCLUSION

In this study, it was seen that there was no difference between the results of repair and non-repair of unilateral nerve injuries distal to the middle level of the middle phalanx, but repair is required in injuries proximal to this level.

Regenerative Strategies in Treatment of Peripheral Nerve Injuries in Different Animal Models

BACKGROUND

Peripheral nerve damage mainly resulted from traumatic or infectious causes; the main signs of a damaged nerve are the loss of sensory and/or motor functions. The injured nerve has limited regenerative capacity and is recovered by the body itself, the recovery process depends on the severity of damage to the nerve, nowadays the use of stem cells is one of the new and advanced methods for treatment of these problems.

METHOD

Following our review, data are collected from different databases "Google scholar, Springer, Elsevier, Egyptian Knowledge Bank, and PubMed" using different keywords such as Peripheral nerve damage, Radial Nerve, Sciatic Nerve, Animals, Nerve regeneration, and Stem cell to investigate the different methods taken in consideration for regeneration of PNI.

RESULT

This review contains tables illustrating all forms and types of regenerative medicine used in treatment of peripheral nerve injuries (PNI) including different types of stem cells " adipose-derived stem cells, bone marrow stem cells, Human umbilical cord stem cells, embryonic stem cells" and their effect on re-constitution and functional recovery of the damaged nerve which evaluated by physical, histological, Immuno-histochemical, biochemical evaluation, and the review illuminated the best regenerative strategies help in rapid peripheral nerve regeneration in different animal models included horse, dog, cat, sheep, monkey, pig, mice and rat.

CONCLUSION

Old surgical attempts such as neurorrhaphy, autogenic nerve transplantation, and Schwann cell implantation have a limited power of recovery in cases of large nerve defects. Stem cell therapy including mesenchymal stromal cells has a high potential differentiation capacity to renew and form a new nerve and also restore its function.

Development and preclinical evaluation of bioactive nerve conduits for peripheral nerve regeneration: A comparative study

In severe peripheral nerve injuries, nerve conduits (NCs) are good alternatives to autografts/allografts; however, the results the available devices guarantee for are still not fully satisfactory. Herein, differently bioactivated NCs based on the new polymer oxidized polyvinyl alcohol (OxPVA) are compared in a rat model of sciatic nerve neurotmesis (gap: 5 mm; end point: 6 weeks). Thirty Sprague Dawley rats are randomized to 6 groups: Reverse Autograft (RA); Reaxon®; OxPVA; OxPVA + EAK (self-assembling peptide, mechanical incorporation); OxPVA + EAK-YIGSR (mechanical incorporation); OxPVA + Nerve Growth Factor (NGF) (adsorption). Preliminarily, all OxPVA-based devices are comparable with Reaxon® in Sciatic Functional Index score and gait analysis; moreover, all conduits sustain nerve regeneration (S100, β-tubulin) without showing substantial inflammation (CD3, F4/80) evidences. Following morphometric analyses, OxPVA confirms its potential in PNI repair (comparable with Reaxon®) whereas OxPVA + EAK-YIGSR stands out for its myelinated axons total number and density, revealing promising in injury recovery and for future application in clinical practice.

Iatrogenic nerve injury in primary and revision reverse total shoulder arthroplasty

INTRODUCTION

Iatrogenic nerve injury in orthopedic surgery can impair functional outcomes. During the last years, a steady increase in the number of performed reverse total shoulder arthroplasties has been reported and complications associated with this procedure are continuously described. Neurological complications, however, remain underreported. The aims of this study were to calculate the incidence of iatrogenic nerve injury after primary and revision reverse total shoulder arthroplasty in a large patient cohort, as well as identify associated patient-and surgery-related risk factors.

MATERIALS AND METHODS

A retrospective review of our institution's internal Reverse Total Shoulder Arthroplasty (RTSA) database from September 2005 to December 2019 was undertaken and 34 patients with iatrogenic nerve injuries were identified, resulting in a neurological complication rate of 2.6%. Group comparisons between patients with nerve injuries (n = 34) and the remaining cohort without nerve injuries (n = 1275) were performed to identify patient- and surgery-related risk factors.

RESULTS

Of the 34 cases with iatrogenic nerve injury, damage to terminal nerve branches occurred in 21 patients, whereas a brachial plexus lesion was diagnosed in the other 13. Nerve revision surgery was necessary in four patients. At final follow-up 13 patients (45%) had residual motor deficits and 17 (59%) had residual sensory deficits. Higher numbers of previous surgeries of the affected shoulder correlated with subsequent nerve injury (p = 0.035). Operative time was significantly longer in patients, who developed a neurologic deficit, showing a correlation between duration of surgery and occurrence of nerve injury (p = 0.013). Patients with neurologic complications were significantly younger than patients without nerve damage (median 68 vs. 72 years, p = 0.017).

CONCLUSIONS

In specialists' hands reverse total shoulder arthroplasty is a rather safe procedure regarding the risk of neurologic injury. However, multiple previous surgeries of the affected shoulder increase the risk of neurological complications. Cases with post-operative neurologic compromise are rare and usually recover well, with few patients suffering long-term functional deficits from iatrogenic nerve injury.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Use of Vascularized, Denervated Muscle Targets for Prevention and Treatment of Upper-Extremity Neuromas

Purpose

Neuroma formation following upper-extremity peripheral nerve injury often results in persistent, debilitating neuropathic pain with a limited response to medical management. Vascularized, denervated muscle targets (VDMTs) offer a newly described surgical approach to address this challenging problem. Like targeted muscle reinnervation and regenerative peripheral nerve targets, VDMTs are used to redirect regenerating axons from an injured nerve into denervated muscle to prevent neuroma formation. By providing a vascularized muscle target that is reinnervated via direct neurotization, VDMTs offer some theoretical advantages in comparison with the other contemporary surgical options. In this study, we followed the short-term pain outcomes of patients who underwent VDMT surgery for neuroma prevention or treatment.

Methods

We performed a retrospective chart review of 9 patients (2 pediatric and 7 adult) who underwent VDMTs either for symptomatic upper-extremity neuromas or as a prophylactic measure to prevent primary neuroma formation. In-person and/or telephone interviews were conducted to assess their postoperative clinical outcomes, including the visual analog pain scale simple pain score.

Results

Of the 9 patients included in this study, 7 underwent VDMT surgery as a prophylactic measure against neuroma formation, and 2 presented with symptomatic neuromas that were treated with VDMTs. The average follow-up was 5.6 ± 4.1 months (range, 0.5-13.2 months). The average postoperative pain score of the 7 adult patients was 1.1 (range, 0-8).

Conclusions

This study demonstrated favorable short-term outcomes in a small cohort of patients treated with VDMTs in the upper extremity. Larger, prospective, and comparative studies with validated patient-reported and objective outcome measures and longer-term follow-ups are needed to further evaluate the benefits of VDMTs in upper-extremity neuroma management and prevention.

Type of study/level of evidence

Therapeutic III.

Frozen vein wrapping for chronic nerve constriction injury reduces sciatic nerve allodynia in a rat model

Background

Autologous vein wrapping (VW) is used in the treatment of recurrent chronic constriction neuropathy and traumatic peripheral nerve injury. However, use of autologous veins is limited by the inability to obtain longer veins of sufficient length for larger sites. Frozen allograft tissue has several advantages, including its availability for large grafts, avoidance of donor-site morbidity, and shorter operation time. Here, we investigated the effect of frozen vein wrapping (FVW) in Wistar rats as a model of sciatic nerve injury.

Results

The rats were grouped by treatment as (i) untreated after chronic constriction injury surgery (CCI; control group), (ii) treated with vein wrapping using freshly isolated vein (VW), and (iii) treated with vein wrapping using frozen vein (FVW). Mechanical allodynia was assessed with von Frey filaments on postoperative days (PODs) 1, 3, 5, 7, and 14. Gene expression of HO-1 was evaluated by quantitative polymerase chain reaction (qPCR). The response of heme oxygenase-1 gene, Hmox-1, expression to VW and FVW was assessed by RT-PCR. Both VW and FVW significantly increased withdrawal threshold levels compared to the untreated control group on POD 1, 3, and 5. Both VW and FVW also showed increased HO-1 expression compared to the CCI group.

Conclusions

FVW increased the withdrawal threshold similar to VW in a rat CCI model for short periods. Frozen vein wrapping using vein allograft without donor site morbidity may be an alternative therapeutic option.

Failure to Compensate: Patients With Nerve Injury Use Their Injured Dominant Hand, Even When Their Nondominant Is More Dexterous

OBJECTIVE

To identify how individuals respond to unilateral upper extremity peripheral nerve injury via compensation (increased use of the nondominant hand). We hypothesized that injury to the dominant hand would have a greater effect on hand use (left vs right choices). We also hypothesized that compensation would not depend on current (postinjury) nondominant hand performance because many patients undergo rehabilitation that is not designed to alter hand use.

DESIGN

Observational survey, single-arm.

SETTINGS

Academic research institution and referral center.

PARTICIPANTS

A total of 48 adults (N=48) with unilateral upper extremity peripheral nerve injury. Another 14 declined participation. Referred sample, including all eligible patients from 16 months at 1 nerve injury clinic and 1 hand therapy clinic.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Hand use (% of actions with each hand) via Block Building Task. Dexterity via Jebsen-Taylor Hand Function.

RESULTS

Participants preferred their dominant hand regardless of whether it was injured: hand usage (dominant/nondominant) did not differ from typical adults, regardless of injured side (P>.07), even though most participants (77%) were more dexterous with their uninjured nondominant hand (mean asymmetry index, -0.16±0.25). The Block Building Task was sensitive to hand dominance (P=2 × 10-4) and moderately correlated with Motor Activity Log amount scores (r2=0.33, P<.0001). Compensation was associated only with dominant hand dexterity (P=3.9 × 10-3), not on nondominant hand dexterity, rehabilitation, or other patient and/or injury factors (P>.1).

CONCLUSIONS

Patients with peripheral nerve injury with dominant hand injury do not compensate with their unaffected nondominant hand, even if it is more dexterous. For the subset of patients unlikely to recover function with the injured hand, they could benefit from rehabilitation that encourages compensation with the nondominant hand.

Creatine promotes the repair of peripheral nerve injury by affecting macrophage polarization

The present study aimed to explore whether creatine promotes the repair of peripheral nerve injury and its possible mechanism. In vitro: RAW264.7 cells were used to investigate the role of proteins related to the JAK2/STAT1 pathway in the polarization of macrophages treated with creatine. In vivo: A sciatic nerve crush model was used. After the injury, IL-4 or creatine was injected. The recovery of motor function was assessed by the rotarod test and sciatic function index at 2, 6, 10, and 16 days after injury. At 16 days after injury, the ultrastructure of the nerve tissue was observed under a transmission electron microscope. Immunostaining were performed at 4 and 16 days to investigate the expression levels of macrophage-related markers as well as the distribution of macrophages after injury. Compared with the IFN-γ group, the group pretreated with creatine showed a significant decrease in p-JAK2 and p-STAT1 in vitro. The motor function of mice in the creatine group (CR₁) and creatine 4 days group (CR₂) was significantly improved compared to the control group (CON). The improvement in the CR₂ group was more significant. Immunostaining showed that infiltrating macrophages mainly comprised M1 macrophages in the CON group and M2 macrophages in the CR group. Our study shows that creatine promotes the repair of peripheral nerve injury by affecting macrophage polarization, possibly through decreasing M1 polarization by inhibiting the JAK2/STAT1 pathway.

Medial three-finger drop in high-energy forearm trauma: An unrecognized peripheral nerve injury. A report of two cases

Case

Absent active extension at metacarpophalangeal (MCP) joints of medial three fingers with intact extension of index finger and thumb following high energy forearm trauma due to recurrent branch of posterior interosseous nerve (RBPIN) injury has not been reported yet. The aim is to highlight an unrecognized sequel of a commonly encountered forearm trauma in two patients who sustained fractures around the elbow and forearm.

Conclusion

In the acute traumatic setting, medial three-finger drop due to RBPIN injury can be missed or misdiagnosed. This has medico-legal and prognostic implications.

Relationship Between Sensibility Tests and Functional Outcomes in Patients With Traumatic Upper Limb Nerve Injuries: A Systematic Review

Objective

To investigate which tests of hand sensibility correlate with functional outcomes in patients with upper limb traumatic nerve injuries and to assess if composite scales of sensibility correlate with functions.

Data Sources

MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched in May 2020, with a supplementary search in July 2020. Reference lists of the included publications were hand searched.

Study Selection

Database search found 2437 records. Eligible studies reported on inferential association between sensibility tests and functions pertaining to adults after upper limb nerve repair. Two reviewers independently assessed eligibility. Fifteen publications were included.

Data Extraction

Extracted data contain patient characteristics, surgical procedure, follow-up duration, sensibility tests, and functional assessments. Two reviewers independently assessed data quality.

Data Synthesis

Fifteen publications involving 849 patients were reviewed. All publications reported on median and/or ulnar nerve injuries. Monofilament tests correlated with Short-Form Health Survey (r=0.548, P<.05), pick-up test (r=0.45, P<.05), and function domain of Patient-Rated Wrist and Hand Evaluation Questionnaire (PRWHE) (r=0.58, P<.05). The 8 studies of static and moving 2-point discrimination provided conflicting correlations with activities of daily living (ADL) and/or the pick-up test. Data for area localization and object/shape identification were equivocal as well. No data were found for Ten test and vibration tests. Rosén score sensory domain correlated with ADL (r=0.59; 95% confidence interval [CI], 0.41-0.72) and PRWHE function domain (r=−0.56, P<.05). Medical Research Council sensory scale was related to pick-up test; return to work status; and Disabilities of the Arm, Shoulder, and Hand questionnaire.

Conclusions

Monofilament tests allow practitioners to gather sensibility data meaningful to patients’ overall recovery of functions after upper limb nerve trauma. For 2-point discrimination and other sensibility tests, practitioners should be aware that improvement in test performance does not necessarily translate to improved hand function. Findings from the composite scales indicate that hand sensibility, in general, is related to functions. Future research on other common sensibility tests is recommended to explore how the test relates to patients’ functions.

Effect of sesamol on damaged peripheral nerves: Evaluation of functional, histological, molecular, and oxidative stress parameters

Objective

Peripheral nerve injury is a clinical problem that may cause sensory and motor inabilities. Sesamol is an antioxidant that can help in repairing damaged central nervous system (CNS) and other organs. The present study aimed to investigate whether the antioxidant effects of sesamol could improve the function, structure, and myelination in rats' damaged peripheral nervous system (PNS).

Materials and Methods

In this study, 28 adult male Wistar rats were randomly divided into four groups. In the sham group, the sciatic nerve was exposed and restored to its place without inducing crush injury. The control received DMSO (solvent) and the two experimental groups received 50 or 100 mg/kg sesamol intraperitoneally for 28 days after sciatic nerve crush injury, respectively. Next, sciatic function index (SFI), superoxide dismutase (SOD) activity, malondialdehyde (MDA) level, expression of nerve growth factor (NGF) and myelin protein zero (MPZ) proteins in the sciatic nerve, and histological indices of the sciatic nerve and gastrocnemius muscle were evaluated.

Results

The results showed that sesamol reduced oxidative stress parameters, increased expression of NGF and MPZ proteins, and improved function and regeneration of the damaged sciatic nerve. Furthermore, a significant regeneration was observed in the gastrocnemius muscle after treatment with sesamol. Although administration of both doses of sesamol was useful, the 100 mg/kg dose was more effective than the 50 mg/kg one.

Conclusion

The results suggest that sesamol may be effective in improving damaged peripheral nerves in rats by reducing oxidative stress and increasing the expression of NGF and MPZ proteins.

Predictors of functional outcome after peripheral nerve injury and compression

STUDY DESIGN

Retrospective cohort study.

INTRODUCTION

Upper-extremity peripheral nerve injuries can impact long-term pain, work performance, and disability, yet there are few studies evaluating treatment outcomes for a large sample of patients with varying peripheral nerve pathology.

PURPOSE OF THE STUDY

The purpose of this study was to identify outcomes of care and predictors of disability and health status in adults with peripheral nerve injuries.

METHODS

We explored medical records from 364 patients treated by a plastic surgeon over a three-year period. Descriptive and inferential statistics compared the Disabilities of the Arm, Shoulder, and Hand, Short-Form 8, and routine intake data between baseline and discharge, diagnosis, and intervention group. Multivariate linear regression models predicted disability, work disability, and physical and mental health at discharge.

RESULTS

We found significant improvements in disability, work disability, pain, depression, and stress. Health status changed minimally. Disability decreased most in patients who were working and who had symptoms fewer than six months. Outcomes were not statistically different between surgical and nonsurgical patients. Disability was the highest in patients with brachial plexus injuries. Multivariate models predicted 35 to 55% of the variance in the outcome measures. Factors that were highly predictive of functional outcomes included work status, household management, pain, depression, stress, and difficulty sleeping.

CONCLUSIONS

Patients with peripheral nerve injuries experience improved pain and disability whether treated surgically or nonsurgically. Maintaining engagement in meaningful home and work roles may improve outcomes. Helping patients manage pain remains important, along with combatting stress, depression, and sleep deprivation.

Comparison of two different decellularization methods for processed nerve allograft

The use of processed nerve allografts as an alternative to autologous nerve grafts, the gold standard treatment for peripheral nerve defects, is increasing. However, it is not widely used in Korea due to cost and insurance issues. Moreover, the main detergent used in the conventional Hudson method is unavailable. Therefore, a new nerve allograft decellularization process is needed. We aimed to compare the traditional Hudson method with a novel decellularization process that may remove cellular content more efficiently while preserving the extracellular matrix (ECM) structure using low concentration sodium dodecyl sulfate (SDS) and nuclease. After each decellularization process, DNA content was measured in nerve tissue. Masson's trichrome staining and scanning electron microscopy were performed to determine the state of preservation of the ECM. A significantly greater amount of DNA content was removed in the novel method, and the ECM structure was preserved in both methods. For the in vivo study, a 15-mm long sciatic nerve defect was created in two groups of Sprague-Dawley rats, and processed nerve allografts decellularized using the Hudson or novel method were transplanted. Functional and histological recovery results were measured 12 weeks post-transplantation. Ankle contracture angle, maximal isometric tetanic force of the tibialis anterior (TA), and the TA mass were compared between the groups, as well as the percent neural tissue (100 × neural area/intrafascicular area). There was no significant difference in functional and histological nerve recovery between the methods. The novel method is appropriate for developing a processed nerve allograft.

Epidemiology of Peripheral Nerve Injuries in Sports, Exercise, and Recreation in the United States, 2009 - 2018

OBJECTIVE

To assess rates of peripheral nerve injuries (PNI) in sport, exercise, and recreational activities.

METHODS

The National Electronic Injury Surveillance System (NEISS) was used to query nerve injuries presenting to emergency departments across the United States. Identified injuries were stratified to those with product codes associated with exercise, sports, or recreation. Injuries only to the upper and lower extremities were included as cranial and spinal cord injuries were excluded. PNI was analyzed by age, sex, sport/recreational activity, race, and evaluated for incidence rates by year and activity. Statistical significance was considered to be P < 0.05.

RESULTS

Between 2009-2018, 551,612 patients presented with PNI from which 120,675 (21.9%) were associated with exercise, sports, or recreation. PNI significantly increased between 2009-2018 (p = 0.002) with an overall incidence rate of 36.9 (95% confidence interval: 28.6, 45.2) per 1,000,000 person-years. A majority of PNI occurred through exercise (n = 56,328, 46.7%). PNI peaked in the fourth and fifth decades in males and females, respectively, with males accounting for significantly more than females (incidence rate ratio: 1.52, 95% confidence interval: 1.18, 1.86; p < 0.0001). White patients had a majority of PNI at 49.3% though African-Americans carried the highest incidence rate at 30.4 (95% confidence interval: 23.8, 36.9) per 1,000,000 person-years. Football had the highest proportion of PNI until age 19 (17.3%) as exercise carried the highest proportion for those 20 and older ranging from 27.9% to 53.8% of PNI.

CONCLUSION

PNIs are rising with participation in exercise, sports, and recreation over this 10-year study period. Injuries predominantly occurred in football for those under 20 and exercise for those 20 and older. Precautions and appropriate training are necessary for individuals participating in high-intensity exercise, sports, or recreation to limit the risk of a devastating neurological injury.

End-to-side neurorrhaphy in peripheral nerves: Does it work?

Acute peripheral nerve injuries are common and can cause physical disabilities with sensory and functional sequelae; they therefore require surgery. The aim of this study was to conduct a systematic review to assess the clinical applicability of end-to-side neurorrhaphy in peripheral nerve reconstruction, based on available evidence. We carried out a systematic review of the literature using MEDLINE/PubMed, EMBASE, Cochrane Library, Web of Science, Scielo and Scopus through March 16, 2021. Most of the selected studies were qualitative and employed nonrandomized groups of patients, without standardized scales for assessing outcomes, which made statistical analysis difficult. Efficacy varied from 24% to 81%. Factors for better outcome included the type of injury, type of injured nerve (sensory, motor or mixed), presence of an epineural window, topography, injury extension <1.3 cm, and intervention within 2 weeks of injury. Clinical studies so far lack scientific evidence on end-to-side neurorrhaphy in peripheral nerve lesions.

The Restorative Effect of Gallic Acid on the Experimental Sciatic Nerve Damage Model

Objective

Peripheral nerve injuries occur mostly as a result of mechanical trauma. Due to the microvascular deterioration in peripheral nerve damage, it becomes challenging to remove free oxygen radicals. Gallic acid is a powerful antioxidant with anti-inflammatory effects and a free radical scavenger. The purpose of the study is to show that gallic acid contributes to the restorative effect in mechanical nerve damage, considering its antioxidant and anti-inflammatory effects.

Methods

Thirty male Sprague Dawley albino mature rats were included in the study. Ten of them constituted the control group, 10 out of 20 rats for which sciatic nerve damage was caused, constituted the saline group, and 10 formed the gallic acid group. Post-treatment motor functions, histological, immunohistochemical, and biochemical parameters of the rats were evaluated.

Results

Compared to the surgery+saline group, lower compound muscle action potential (CMAP) latency, higher CMAP amplitude, and higher inclined plane test values were found in the surgery+gallic acid group. Similarly, a higher nerve growth factor (NGF) percentage, a higher number of axons, and a lower percentage of fibrosis scores were observed in the surgery+gallic acid group. Finally, lower tissue malondialdehyde (MDA) and higher heat shock protein-70 (HSP-70) values were determined in the surgery+gallic acid group.

Conclusion

Gallic acid positively affects peripheral nerve injury healing due to its anti-inflammatory and antioxidant effects. It has been thought that gallic acid can be used as a supportive treatment in peripheral nerve damage.

Imaging of traumatic peripheral nerve injuries

Nerves are commonly injured in case of blunt or penetrating trauma to the extremities. Patients with nerve injuries have profound consequences and thus a timely decision for operative management is a very important. Conventionally, management decisions have been based on clinical findings, patient course and electrophysiological studies. However, imaging modalities have an enormous role not only in localizing and grading of the nerve injuries but also in the follow-up of the nerve recovery. High-resolution ultrasound (HUS) is the modality of choice for evaluation of peripheral nerves. Magnetic resonance neurography (MRN) plays a complementary role, enabling better assessment of muscle changes and deeper nerves. Corresponding to the injured layer of the cross-section of the nerve, imaging manifestations differ in different grades of injury. Since imaging cannot detect ultrastructural changes at the microscopic level, thus there may be overlap in the imaging findings. Herewith, we discuss the imaging findings in different grades of nerve injury and propose a simple 3-tier grading for imaging (HUS and MRN) assessment of peripheral nerve injuries.

Lower extremity nerve injuries and their management at a referral center in Mexico City

OBJETIVO

Describir el manejo de las lesiones nerviosas de extremidad inferior atendidas en un centro de referencia en cirugía plástica y reconstructiva en la Ciudad de México.

MÉTODO

Estudio descriptivo, transversal y retrospectivo, en el que se evaluaron los expedientes clínicos de pacientes atendidos por lesiones nerviosas de extremidad inferior entre 2010 y 2018.

RESULTADOS

Se incluyeron 21 pacientes, 14 hombres (66.6%) y 7 mujeres (33.3%), con una edad promedio de 30.00 ± 8.89 años. Las lesiones en la extremidad derecha fueron más prevalentes (52.3%). El mecanismo de lesión más común fue por herida por proyectil de arma de fuego (28.5%) o por accidente automovilístico (13.6%). Los nervios más afectados fueron el ciático (38.0%) y el peroneo (38.0%), seguidos por el tibial (9.5%), el peroneo y el tibial simultáneamente (9.5%) y el femoral (4.7%). Las medidas de tratamiento más empleadas fueron las transferencias nerviosas (7 casos, 33.3%) y la aplicación de injertos nerviosos para el manejo de brechas (7 casos, 33.3%).

CONCLUSIONES

La reparación de las estructuras nerviosas de la extremidad inferior ha recibido poca atención. Sin embargo, nuestro estudio muestra que es posible aplicar diversas estrategias reconstructivas microquirúrgicas, buscando mejorar los desenlaces funcionales de los pacientes.

OBJECTIVE

To describe the management of lower extremity nerve injuries at a plastic and reconstructive surgery referral center in Mexico City.

METHOD

A descriptive, transversal and retrospective study was performed, evaluating clinical records of patients with lower extremity nerve injuries managed in our center between 2010 and 2018.

RESULTS

Twenty-one patients were included, 14 males (66.6%) and 7 females (33.3%); mean age was 30.00 ± 8.89 years. Right-sided injuries were more prevalent (52.3%). The most common etiologies were gunshot injuries (28.5%) and motor vehicle accidents (13.6%). The most frequently affected nerves were the sciatic (38.0%) and the peroneal nerves (38.0%), followed by the tibial (9.5%), simultaneous tibial and peroneal nerve injury (9.5%) and the femoral nerve (4.7%). Nerve transfers (7 cases, 33.3%) and autologous nerve grafts (7 cases, 33.3%) were the preferred surgical techniques for injury management.

CONCLUSIONS

Repair of lower extremity nerve injuries has not been popularized, however our study shows that several microsurgical reconstructive strategies are available in order to improve functional outcomes.

A Porcine Model of Peripheral Nerve Injury Enabling Ultra-Long Regenerative Distances: Surgical Approach, Recovery Kinetics, and Clinical Relevance

BACKGROUND

Millions of Americans experience residual deficits from traumatic peripheral nerve injury (PNI). Despite advancements in surgical technique, repair typically results in poor functional outcomes due to prolonged periods of denervation resulting from long regenerative distances coupled with slow rates of axonal regeneration. Novel surgical solutions require valid preclinical models that adequately replicate the key challenges of clinical PNI.

OBJECTIVE

To develop a preclinical model of PNI in swine that addresses 2 challenging, clinically relevant PNI scenarios: long segmental defects (≥5 cm) and ultra-long regenerative distances (20-27 cm). Thus, we aim to demonstrate that a porcine model of major PNI is suitable as a potential framework to evaluate novel regenerative strategies prior to clinical deployment.

METHODS

A 5-cm-long common peroneal nerve or deep peroneal nerve injury was repaired using a saphenous nerve or sural nerve autograft, respectively. Histological and electrophysiological assessments were performed at 9 to 12 mo post repair to evaluate nerve regeneration and functional recovery. Relevant anatomy, surgical approach, and functional/histological outcomes were characterized for both repair techniques.

RESULTS

Axons regenerated across the repair zone and were identified in the distal stump. Electrophysiological recordings confirmed these findings and suggested regenerating axons reinnervated target muscles.

CONCLUSION

The models presented herein provide opportunities to investigate peripheral nerve regeneration using different nerves tailored for specific mechanisms of interest, such as nerve modality (motor, sensory, and mixed fiber composition), injury length (short/long gap), and total regenerative distance (proximal/distal injury).

Application of bioactive hydrogels combined with dental pulp stem cells for the repair of large gap peripheral nerve injuries

Due to the limitations in autogenous nerve grafting or Schwann cell transplantation, large gap peripheral nerve injuries require a bridging strategy supported by nerve conduit. Cell based therapies provide a novel treatment for peripheral nerve injuries. In this study, we first experimented an optimal scaffold material synthesis protocol, from where we selected the 10% GFD formula (10% GelMA hydrogel, recombinant human basic fibroblast growth factor and dental pulp stem cells (DPSCs)) to fill a cellulose/soy protein isolate composite membrane (CSM) tube to construct a third generation of nerve regeneration conduit, CSM-GFD. Then this CSM-GFD conduit was applied to repair a 15-mm long defect of sciatic nerve in a rat model. After 12 week post implant surgery, at histologic level, we found CSM-GFD conduit could regenerate nerve tissue like neuron and Schwann like nerve cells and myelinated nerve fibers. At physical level, CSM-GFD achieved functional recovery assessed by a sciatic functional index study. In both levels, CSM-GFD performed like what gold standard, the nerve autograft, could do. Further, we unveiled that almost all newly formed nerve tissue at defect site was originated from the direct differentiation of exogeneous DPSCs in CSM-GFD. In conclusion, we claimed that this third-generation nerve regeneration conduit, CSM-GFD, could be a promising tissue engineering approach to replace the conventional nerve autograft to treat the large gap defect in peripheral nerve injuries.

•

A novel 3^rd generation nerve conduit was successfully constructed and applied for repairing peripheral nerve injuries (PNI).

•

Dental pulp stem cells (DPSCs) was optimized as an ideal seeding cells for nerve regeneration.

•

A bioactive system combining GelMA with human bFGF and DPSCs could reconstruct the long gap PNI within 12 weeks in vivo.

•

Our system could achieve the same outcome in nerve repair as that of autografting, a routine treatment for PNI.

•

The proposed bioactive system may trigger an evolutional change into the current clinical practice in managing PNI.

•

The majority of the regenerated nerve tissue was originated from the donor’s dental pulp stem cells.

Development of vascularized nerve scaffold using perfusion-decellularization and recellularization

INTRODUCTION

Vascularized nerve grafts (VNG) may offer an advantage in peripheral nerve regeneration by avoiding ischemic damage and central necrosis observed in non-VNG, particularly for the treatment of large and long nerve defects. However, surgical complexity, donor site morbidity and limited nerve availability remain important drawbacks for the clinical use of VNG. Here we explore the potential of perfusion-decellularization for bioengineering a VNG to be used in peripheral nerve reconstruction.

METHODS

Porcine sciatic nerves were surgically procured along with their vascular pedicle attached. The specimens were decellularized via perfusion-decellularization and preservation of the extracellular matrix (ECM), vascular patency and tissue cytokine contents were examined. Scaffold reendothelialization was conducted with porcine aortic endothelial cells in a perfusion-bioreactor.

RESULTS

Morphologic examination of decellularized VNG and analysis of the DNA content demonstrated cell clearance whereas ECM content and structures of the nerve fascicles were preserved. Using 3D micro-computed tomography imaging we observed optimal vasculature preservation in decellularized scaffolds, down to the capillary level. Cytokine quantification demonstrated measurable levels of growth factors after decellularization. Endothelial cell engraftment of the large caliber vessels was observed in reendothelialized scaffolds.

CONCLUSIONS

In this study we provide evidence that perfusion-decellularization can be used to create vascularized nerve scaffolds in which the vasculature and the ECM component are well preserved. As compared to non-vascularized conduits, engineered vascularized nerve scaffolds may represent an ideal approach for promoting better nerve regeneration in larger nerve defect reconstructions.

Return to sporting activity after ulnar nerve transposition for isolated neuritis in competitive overhead athletes

BACKGROUND

Although ulnar neuritis can occur secondary to ulnar collateral ligament pathology, stress fractures, and traction apophysitis, isolated ulnar nerve dysfunction can lead to medial elbow pain. The purpose of this study was to evaluate the short-term outcomes of overhead athletes undergoing anterior ulnar nerve transposition for ulnar neuropathy.

METHODS

All overhead athletes who underwent isolated ulnar nerve transposition between 2009 and 2016 for refractory ulnar neuritis were identified. The primary outcome was return to sport, and secondary outcome measures included the Kerlan-Jobe Orthopaedic Clinic score; Mayo Elbow Performance Score; Quick Disabilities of the Arm, Shoulder and Hand score; Single Assessment Numeric Evaluation score; and visual analog scale score for pain. Complication and reoperation rates were recorded.

RESULTS

A total of 26 overhead athletes (21 male and 5 female athletes) underwent ulnar nerve transposition at an average age of 18.4 years (range, 11-25 years). Of the patients, 24 (92%) returned to their sporting activity at an average of 2.7 months postoperatively, including 16 (62%) at the previous level of play. The average visual analog scale pain score improved from 4.7 (±2.5) to 0.4 (±1.5) (P = .015). The average postoperative patient-reported outcome scores were as follows: Kerlan-Jobe Orthopaedic Clinic score, 80 (95% confidence interval [CI], 72.7-87.0); Single Assessment Numeric Evaluation score, 85 (95% CI, 75.4-94.7); Quick Disabilities of the Arm, Shoulder and Hand score, 5 (95% CI, 2.1-7.7); and Mayo Elbow Performance Score, 91 (95% CI, 86.8-96.0).

CONCLUSION

Cubital tunnel syndrome can cause medial elbow pain in overhead athletes in the presence of a normal ulnar collateral ligament. At mid-term follow-up, 92% of overhead athletes returned to sport after ulnar nerve transposition, with 62% resuming their previous level of performance.

Efficacy of tubing technique with biomaterials compared to direct coaptation technique after peripheral neurotmesis in nerve healing and return to functionality in young adult rats: a systematic review protocol

BACKGROUND

Peripheral nerves are constant targets of traumatic injury which may result in neurotmesis and which invariably requires surgical treatment. In view of this, tissue engineering studies developed biomaterials which were first tested in animal models and used as a guide for nerve stumps in the procedure in order to speed up the healing process. Therefore, the aim of this study is to evaluate the efficacy of biomaterials used in tubing technique on healing and histological and functional recovery after peripheral nerve neurotmesis in rats.

METHODS

We will search PubMed/MEDLINE, Embase, Web of Science, LILACS, and CENTRAL (from inception onwards). Grey literature will be identified through searching dissertation databases, guidelines, policy documents, and reports. We will include randomized and non-randomized trials conducted in young adult rats with peripheral neurometsis undergoing surgical repair through tubing technique with biomaterials. Primary outcomes will be histomorphometry, immunohistochemistry of the nerve tissue, and sciatic functional index. Secondary outcome will be nerve macroscopic evaluation. Two reviewers will independently screen all citations, full-text articles, and abstract data. Potential conflicts will be resolved through discussion. The methodological quality (or risk of bias) of individual studies will be appraised using an appropriate tool. If feasible, we will conduct random effects meta-analysis.

DISCUSSION

This systematic review of animal studies will identify, evaluate, and synthetize the evidence on the the efficacy of tubing technique with biomaterials compared to direct coaptation technique after peripheral neurotmesis in nerve healing and return to functionality.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018106042.

More severe cold intolerance is associated with worse sensory function after peripheral nerve repair or decompression

The aim of the study is to investigate the correlation between cold intolerance and sensory function after repair of nerve transection or decompression of peripheral neuropathy in the upper extremity. We included patients with abnormal cold sensitivity who had a score of 30 or more in the Cold Intolerance Symptom Severity Questionnaire. There were 30 individuals after surgery to repair nerve transection and 30 with compression neuropathy, aged between 18-65 years. We used the Cold Intolerance Symptom Severity Questionnaire to evaluate cold intolerance and the Rosen Score to evaluate sensory function. There was a significant negative correlation between cold intolerance and sensory function in both peripheral nerve transections and compression neuropathies. We conclude that greater cold intolerance is associated with worse sensory function in peripheral nerve injuries. Interventions for sensory function in cold intolerance treatment may reduce the severity of cold intolerance. Level of evidence: III.

Neuroprotective Effects of Lacosamide in Experimental Peripheral Nerve Injury in Rats : A Prospective Randomized and Placebo-Controlled Trial

OBJECTIVE

To evaluate the neuroprotective effects of lacosamide after experimental peripheral nerve injury in rats.

METHODS

A total of 28 male wistar albino rats weighing 300-350 g were divided into four groups. In group I, the sciatic nerve exposed and the surgical wound was closed without injury; in group II, peripheral nerve injuries (PNI) was performed after dissection of the nerve; in group III, PNI was performed after dissection and lacosamide was administered, and in group IV, PNI was performed after dissection and physiological saline solution was administered. At 7 days after the injury all animals were sacrificed after walking track analysis. A 5 mL blood sample was drawn for biochemical analysis, and sciatic nerve tissues were removed for histopathological examination.

RESULTS

There is low tissue damage in lacosamide treated group and antioxidant anzymes and malondialdehyde levels were higher than non-treated and placebo treated group. However there was no improvement on clinical assessment.

CONCLUSION

The biochemical and histological analyses revealed that lacosamide has neuroprotective effect in PNI in rats. This neuroprotective capacity depends on its scavenger role for free oxygen radicals by increasing antioxidant enzyme activity.

Nerve high-resolution ultrasonography in peripheral nerve injuries associated with supracondylar humeral fractures in children

To evaluate nerve high-resolution ultrasonography (HRUS) as diagnostic tool in children with supracondylar humeral fractures (SHF)-related peripheral nerve injuries (PNIs), we selected at least one illustrative case for each upper limb nerve usually involved in SHF (i.e. median, radial and ulnar nerve), in which HRUS evaluation added a useful contribution in diagnostic and therapeutic choices. We selected four patients (3 males, 1 female, aged between 7 and 12 years). Involved nerves were median (2), radial (1) and ulnar (1). HRUS results can actively modify the management of children with SHF-related PNIs, especially when combined with clinical and EDX. HRUS should be used routinely in evaluation of children with SHF-related PNIs.

Peripheral Nerve Conduit: Materials and Structures

Peripheral nerve injuries (PNIs) are the most common injury types to affect the nervous system. Restoration of nerve function after PNI is a challenging medical issue. Extended gaps in transected peripheral nerves are only repaired using autologous nerve grafting. This technique, however, in which nerve tissue is harvested from a donor site and grafted onto a recipient site in the same body, has many limitations and disadvantages. Recent studies have revealed artificial nerve conduits as a promising alternative technique to substitute autologous nerves. This Review summarizes different types of artificial nerve grafts used to repair peripheral nerve injuries. These include synthetic and natural polymers with biological factors. Then, desirable properties of nerve guides are discussed based on their functionality and effectiveness. In the final part of this Review, fabrication methods and commercially available nerve guides are described.

Novel approaches using mesenchymal stem cells for curing peripheral nerve injuries

Peripheral nerve injury (PNI) is a common life-changing disability of peripheral nervous system with significant socioeconomic consequences. Conventional therapeutic approaches for PNI have several drawbacks such as need to autologous nerve scarifying, surplus surgery, and difficult accessibility to donor nerve; therefore, other therapeutic strategies such as mesenchymal stem cells (MSCs) therapy are getting more interesting. MSCs have been proved to be safe and efficient in numerous degenerative diseases of central and peripheral nervous systems. In this paper, we review novel biotechnological advancements in treating PNI using MSCs.

The addition of albumin improves Schwann cells viability in nerve cryopreservation

The purpose of the current study was to establish a valid protocol for nerve cryopreservation, and to evaluate if the addition of albumin supposed any advantage in the procedure. We compared a traditional cryopreservation method that uses dimethyl sulfoxide (DMSO) as cryoprotectant, to an alternative method that uses DMSO and albumin. Six Wistar Lewis rats were used to obtain twelve 20 mm fragments of sciatic nerve. In the first group, six fragments were cryopreserved in 199 media with 10% DMSO, with a temperature decreasing rate of 1 °C per minute. In the second group, six fragments were cryopreserved adding 4% human albumin. The unfreezing process consisted of sequential washings with saline in the first group, and saline and 20% albumin in the second group at 37 °C until the crioprotectant was removed. Structural evaluation was performed through histological analysis and electronic microscopy. The viability was assessed with the calcein-AM (CAM) and 4',6-diamino-2-fenilindol (DAPI) staining. Histological results showed a correct preservation of peripheral nerve architecture and no significant differences were found between the two groups. However, Schwann cells viability showed in the CAM-DAPI staining was significantly superior in the albumin group. The viability of Schwann cells was significantly increased when albumin was added to the nerve cryopreservation protocol. However, no significant structural differences were found between groups. Further studies need to be performed to assess the cryopreserved nerve functionality using this new method.

TRANSFER OF NERVE BRANCHES OF THE FLEXOR CARPI RADIALIS TO THE POSTERIOR INTEROSSEOUS NERVE

Objective:

The objective of this paper was to study the anatomical variations of the flexor carpi radialis muscle (FCR) and determine in cadaver limbs whether the FCR nervous branch can be connected to the posterior interosseous nerve (PIN) without tension and how close to the target muscles the transfer can be performed.

Method:

Thirty cadaveric upper limbs were dissected.

Results:

The FCR received exclusive innervation of the median nerve, distally to the intercondylar line of the humerus. In 5 limbs, an isolated branch was found and in 25, a common trunk with other nervous branches occurred. We investigated whether the branch for the FCR was long enough to be transferred to the PIN. The diameter of the nerve branch for the FCR corresponded on average to 50% of the PIN.

Conclusion:

In 12 limbs, the branch destined to the FCR could be connected to the PIN, distally to the nerve branches to the supinator muscle even during the movements of the forearm and the elbow. In 18 specimens, it was necessary to mobilize the PIN for this innervation. Level of Evidence IV, Case Series.

PERIPHERAL NERVE INJURY IN SPORTS

SUMMARY – Peripheral nerve injuries in sports are rare. Peripheral nerve injuries in sports are caused by pressure, stretching, or bone fracture. Peripheral nerve injuries are more frequent on upper limbs, and the type of injury is determined by the type of sport. According to Seddon, we distinguish 3 levels of injury: 1) neurapraxia; 2) axonotmesis; and 3) neurotmesis. Diagnosis must be reached as early as possible to enable timely initiation of appropriate treatment. The diagnostics of peripheral nerve injuries includes electromyography and nerve conduction studies, somatosensory evoked potentials, magnetic resonance imaging, and ultrasound. Proximal nerve injuries have a poorer prognosis for neurologic recovery.

Ultrasound Diagnosis of Postoperative Complications of Nerve Repair

BACKGROUND

Peripheral nerve injuries often undergo surgical repair, but poor postoperative functional recovery is frequently observed.

CASE DESCRIPTION

We describe 4 cases of traumatic nerve lesions in whom postoperative recovery was prevented by complications such as detachment of nerve sutures or neuroma growth. To the best of our knowledge, no similar cases have been reported in literature so far. It is important to obtain an early diagnosis of such condition because it prevents recovery and delays reintervention, which should be performed before complete muscle denervation and atrophy.

CONCLUSION

Nerve ultrasound is a valuable tool in traumatic nerve injury and has proven to be useful in postoperative follow-up, especially in diagnosing surgical complications such as detachment of nerve direct sutures.

[Nerve injuries and traumatic lesions of the brachial plexus : Imaging diagnostics and therapeutic options]

CLINICAL/METHODICAL ISSUE

Traumatic lesions of peripheral nerves and the brachial plexus are feared complications because they frequently result in severe functional impairment. The prognosis is greatly dependent on the correct early diagnosis and the right choice of treatment regimen. It is important to distinguish between open and closed injuries.

STANDARD RADIOLOGICAL METHODS

Initial imaging must critically evaluate or prove nerve continuity and is commonly achieved by high-resolution ultrasonography. During the further course, reactive soft tissue alterations, such as constrictive scarring or neuroma formation can be detected. In the case of deep nerve and plexus injuries this can be excellently achieved by dedicated magnetic resonance neurography (MRN) sequences.

METHODICAL INNOVATIONS

The signal yield from brachial plexus imaging can be critically enhanced by the use of dedicated surface coil arrays. Furthermore, diffusion tensor imaging (DTI) may enable the regeneration potential of a nerve lesion to be recognized in the future.

PERFORMANCE

Multiple reports have shown that neurosonography enables a precise evaluation of peripheral nerve structures (up to 90% sensitivity and 95% specificity in nerve transection) and that the method can critically impact on therapeutic decision-making in 60%. Currently, there are only few quantitative data on the exact performance of MRN in traumatic nerve lesions; however, individual reports indicate a high level of agreement with intraoperative findings.

PRACTICAL RECOMMENDATIONS

In the initial work-up, especially in the case of peripheral, superficial and lesser nerve injuries, neurosonography is the preferred imaging approach to evaluate nerve integrity and the extent of nerve lesions. In the case of extensive nerve injury of proximal nerves and structures of the plexus as well as in the case of suspected root avulsion MRN is the method of choice.

Dorsal scapular nerve injury after trigger point injection into the rhomboid major muscle: A case report

BACKGROUND AND OBJECTIVE

We report the case of a patient who presented with right dorsal scapular neuropathy after a trigger point injection into the right rhomboid major muscle. Through a nerve conduction study and electromyography, we demonstrated dorsal scapular nerve injury in this patient.

CASE REPORT

A 38-year-old man complained that his right shoulder functioned less optimally during push-up exercises after a trigger point injection 4 weeks prior. Physical examination revealed mildly reduced right shoulder retractor muscle strength compared with the left side. We performed a nerve conduction velocity test and electromyography 5 weeks after the injection. The compound muscle action potential of the right dorsal scapular nerve showed low amplitude (left vs. right side: 5.2 vs. 1.6 mV) and delayed latency (left vs. right side: 4.9 vs. 6.8 ms). Positive sharp wave (1+) and mildly reduced recruitment were seen on electromyography of the rhomboid major muscle. The findings of the nerve conduction velocity test and electromyography indicated partial right dorsal scapular neuropathy. The nerve injury seemed to have been caused by the needle inserted during trigger point injection.

CONCLUSION

Clinicians should pay attention to the occurrence of dorsal scapular nerve injury when performing trigger point injection into the rhomboid muscle.

Nerve conduits for treating peripheral nerve injuries: A systematic literature review

Peripheral nerve injuries are a major public health problem. Nerve conduits have been developed in the recent years, although it is still not clear if they should replace nerve grafting and neurorrhaphy. This systematic review aims to gather evidence regarding the use of nerve conduits for peripheral nerve repair. The following electronic databases were searched: MEDLINE, Cochrane Library (CENTRAL) and Embase. Study selection and data extraction followed the PRISMA guidelines. The systematic review of the literature retrieved 6767 articles. Only 27 studies were retained accounting for 1022 patients: 10 randomized controlled trials, 15 case series and 2 cohort studies. Ten different types of tubes were described and a variety of evaluation methods were used to assess outcomes in terms of efficacy (motor and sensory recovery) and complications. The Semmes-Weinstein monofilament test and the static and moving 2-point discrimination test were the most commonly applied tests to evaluate nerve recovery. In general, outcomes showed no significant difference between groups. Synthetic conduits had more complications. Despite major methodological limitations in the studies, we can conclude that use of nerve conduits is preferable over suture repair and nerve grafting, as the functional recovery rates are above 80%. The choice of conduit is based on the surgeon's expertise, but use of synthetic conduits is discouraged due to their higher complication rates.

[Neurosurgical position causes peripheral nerve injuries?]

BACKGROUND

Positioning during neurosurgical procedures is a challenge for surgical teams even if precautions are taken, the mechanisms underlying peripheral nerve injury (elongation, compression or ischaemia) are latent and it is important to know the frequency of occurrence in our environment.

OBJECTIVE

To analyze the frequency of peripheral nerve injury secondary to surgical positioning.

MATERIALS AND METHODS

Prospective study including 163 patients scheduled for neurosurgical procedures. Four groups: supine, lateral, ventral and park bench were analyzed by neurological exploration in order to detect injury and relate with risk factors already described.

RESULTS

In this study 112 patients were included, two patients who were under park bench position experienced paresthesias in ulnar region of less than 24 hours' duration; statistically significant correlation with body weight greater than 85kg.

CONCLUSION

The incidence of peripheral nerve injury is low, understanding the mechanisms that may originate it helps towards prevention and early detection of complications.

Ulnar nerve paralysis after forearm bone fracture

Paralysis or nerve injury associated with fractures of forearm bones fracture is rare and is more common in exposed fractures with large soft-tissue injuries. Ulnar nerve paralysis is a rare condition associated with closed fractures of the forearm. In most cases, the cause of paralysis is nerve contusion, which evolves with neuropraxia. However, nerve lacerations and entrapment at the fracture site always need to be borne in mind. This becomes more important when neuropraxia appears or worsens after reduction of a closed fracture of the forearm has been completed. The importance of diagnosing this injury and differentiating its features lies in the fact that, depending on the type of lesion, different types of management will be chosen.

Negative Neurodynamic Tests Do Not Exclude Neural Dysfunction in Patients With Entrapment Neuropathies

Objective

To examine differences in somatosensory phenotypes of patients with positive and negative neurodynamic tests and compare these with healthy participants.

Design

Case-control study.

Setting

University department.

Participants

Patients with electrodiagnostically confirmed carpal tunnel syndrome (CTS) (n=53) and people without CTS (n=26) participated in this study (N=79). Patients with CTS were subgrouped according to the results of the upper limb neurodynamic tests biasing the median nerve into patients with positive or negative neurodynamic tests.

Interventions

Not applicable.

Main Outcome Measure

All participants underwent quantitative sensory testing in the median innervated territory of their hand.

Results

Only 46% of patients with CTS had positive neurodynamic tests. No differences were identified between groups for pain thresholds (P>.247). However, patients with CTS had increased mechanical (P<.0001) and thermal detection thresholds (P<.0001) compared with people without CTS. Patients with negative neurodynamic tests had a more pronounced vibration detection deficit (mean, 7.43±0.59) than people without CTS (mean, 7.89±0.22; P=.001). Interestingly, warm detection was the only domain differentiating positive (mean, 4.03°C±2.18°C) and negative neurodynamic test groups (6.09°C±3.70°C, P=.032), with patients with negative neurodynamic tests demonstrating increased loss of function.

Conclusions

Patients with negative neurodynamic tests seem to have a more severe dysfunction of the unmyelinated fiber population. Our findings suggest that neurodynamic tests should not be used in isolation to judge neural involvement. Rather, they should be interpreted in the context of loss of function tests of the small fiber domain.

Gene expression profile comparison in the penile tissue of diabetes and cavernous nerve injury-induced erectile dysfunction rat model

PURPOSE

To investigate the effects of cavernous nerve injury (CNI) on gene expression profiles in the cavernosal tissue of a CNI-induced erectile dysfunction (ED) model and to provide a basis for future investigations to discover potential target genes for ED treatment.

MATERIALS AND METHODS

Young adult rats were divided randomly into 2 groups: sham operation and bilateral CN resection. At 12 weeks after CNI we measured erectile responses and performed microarray experiments and gene set enrichment analysis to reveal gene signatures that were enriched in the CNI-induced ED model. Alterations in gene signatures were compared with those in the diabetes-induced ED model. The diabetic-induced ED data is taken from GSE2457.

RESULTS

The mean ratio of intracavernosal pressure/blood pressure for the CNI group (0.54±0.4 cmH2O) was significantly lower than that in the sham operation group (0.73±0.8 cmH2O, p<0.05). Supervised and unsupervised clustering analysis showed that the diabetes- and CNI-induced ED cavernous tissues had different gene expression profiles from normal cavernous tissues. We identified 46 genes that were upregulated and 77 genes that were downregulated in both the CNI- and diabetes-induced ED models.

CONCLUSIONS

Our genome-wide and computational studies provide the groundwork for understanding complex mechanisms and molecular signature changes in ED.

Nerve injuries of the upper extremity associated with vascular trauma-surgical treatment and outcome

Peripheral nerve injuries are often associated with injuries of adjacent tissue. As a result of anatomic proximity between nerves and vascular structures, there is a high chance of combined injuries of these structures (23 %). The aim of our study is to describe and analyze associated nerve and vascular injuries of the upper extremity in patients treated at the Clinic of Neurosurgery in Belgrade over a 10-year period. This study included 83 patients that received surgical treatment at the Clinic of Neurosurgery in Belgrade after having been diagnosed with upper extremity nerve injury. The study included all patients that satisfied these criteria over a period of 10 years. The patients with associated vascular injuries, 36 of them, were considered our study group, while 47 patients without associated vascular injuries were considered our control group. Finally, we compared treatment outcome between these groups. The final outcome evaluation was performed 2 years after surgical treatment. In our study group, 84.8 % surgical nerve repair was successful (fair, good, and excellent outcome), while in the control group (patients without vascular injury), surgical nerve repair was successful in 87.9 %. The overall satisfactory neurological outcome (M3-M5) was present in 86.6 % of nerve repairs. Our study shows that there is no significant difference between the treatment outcome in patients with associated nerve and vascular injuries and patients with isolated nerve injuries if they are diagnosed in time and treated appropriately. Successful treatment can only be accomplished through a multidisciplinary approach undertaken by a highly qualified medical team.

Peripheral nerve injuries: Long term follow-up results of rehabilitation

BACKGROUND

Peripheral nerve injury (PNI) is a common problem in the world resulting with severe disability. Etiological data is different in studies because of the study period, patient population, economic status, and workplace safety policies of the different countries.

OBJECTIVE

To define epidemiological and etiological data of our patients with peripheral nerve injury and to identify factors influencing efficacy of rehabilitation methods and recovery.

METHODS

Patients were compared by means of electromyography and muscle strength changes. Influence of orthotics use, disease interval and type of physical therapy (electrical stimulation or EMG biofeedback) was assessed.

RESULTS

There was no significant difference between groups. But we found weak correlation between EMG and motor changes. There was no difference in EMG and motor score changes in terms of orthotics use and type of physical therapy. When the patients were grouped according to EMG changes, we found significant difference by disease interval. Disease interval was longest in patients with no change in EMG. When the patients were grouped according to motor score changes, there was no significant difference by disease interval.

CONCLUSION

Etiology of the patients didn't affect long term results in peripheral nerve injury. The results of this study might help rehabilitation teams to guide their follow-up.

Evaluation of pediatric upper extremity peripheral nerve injuries

INTRODUCTION

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Winged scapula incidence and upper limb morbidity after surgery for breast cancer with axillary dissection

PURPOSE

The aim of this study was to determine the incidence of winged scapula after breast cancer surgery, its impact on shoulder morbidity and difference in incidence according to surgery type.

METHODS

Patients with breast cancer and surgical indication for axillary dissection were included. A total of 112 patients were surveyed with one physical evaluation before the surgery and others 15, 30, 90, and 180 days after. Winged scapula was assessed with test proposed by Hoppenfeld. Shoulder range of motion (ROM) was assessed with goniometer for flexion, extension, adduction, abduction, internal rotation, and external rotation. A verbal scale from 0 to 10 was used to assess pain.

RESULTS

Winged scapula incidence was 8.0 % 15 days after surgery. Two patients recovered from winged scapula 90 days after surgery and four more 180 days after surgery, while three patients still had winged scapula at this time. The incidence after 15 days from surgery was 20.9 and 22.6 % among patients submitted to sentinel node biopsy or axillary lymphadenectomy (AL), respectively (p < 0.01). There was no statistical difference of incidence according to breast surgery type. Operated side shoulder flexion, adduction, and abduction ROM changes were statistically different in patients with or without winged scapula. The mean reduction was higher in patients with winged scapula. Both groups showed the same pattern over time in pain.

CONCLUSION

Winged scapula incidence was 8.0 % and was higher in AL, and prevalence decreased during 6 months after surgery. Patients who developed winged scapula had more shoulder flexion, adduction, and abduction limitation.

Introduction of a New Suture Method in Repair of Peripheral Nerves Injured with a Sharp Mechanism

BACKGROUND

The standard method for repair of an injured peripheal nerve is epineural repair with separate sutures. Herein we describe a method in which the nerve is sutured with continous sutures. In fact this method has not been utilized for nerve repair previously and our purpose was to compare it to the standard method. If it proved to be successful it would replace the standard method in certain circumstances.

METHODS

The proposal of the clinical trial was given a reference number form the ethics comitee. 25 dogs in which the scaitic nerve was cut by a sharp blade under genaeral anesthesia were divided randomly into three groups: control (5 dogs), repair of sciatic nerve with simple sutures (10) and repair with continous sutures (10). In the control group the nerve was not repaired at all. After 6 weeks the dogs were killed and the nerve was studied by light and electronic microscopes. The amount of consumed suture material, time of repair, myelin thickness and axon diiameter were examined. Ultrastructural studies were performed to assess degeneration and regeneration findings.

RESULTS

Time of repair and the amount of consumed suture material were significantly lower in the continous group (P<0.001). No difference was found with regard to light microscopy findings and regeneration was confirmed by electron microscopy in the continous group.

CONCLUSION

The method described in the present study, provided a result similar to the standard method. Though undobtfully it has some limitations, can replace the standard method in many circumstances.

Successful Reconstruction of Nerve Defects Using Distraction Neurogenesis with a New Experimental Device

INTRODUCTION

Repair of peripheral nerve injuries is an intensive area of challenge and research in modern reconstructive microsurgery. Intensive research is being carried out to develop effective alternatives to the standard nerve autografting, avoiding its drawbacks. The aim of the study was to evaluate the effectiveness of a newly designed mechanical device for the reconstruction of the sciatic nerve in rats in comparison to nerve autografting and to assess the pain during the period of distraction neurogenesis.

METHODS

Fourteen Sprague Dawley rats were used and randomly assigned into 2 groups with 7 rats in each group; group A (Nerve Autografting group) in which a 10-mm segment of the sciatic nerve was resected and rotated 180 degrees, then primary end-to-end neurorrhaphy was performed in the reverse direction; group B (Nerve Lengthening group) in which the mechanical device was inserted after surgical resection of 10 mm of the sciatic nerve, then secondary end-to-end neurorrhaphy was performed after completing the nerve lengthening. Thirteen weeks later, assessment of the functional sciatic nerve recovery using static sciatic index (SSI) was performed. Furthermore, fourteen weeks after the nerve resection, assessment of the nerve regeneration with electrophysiological study and histological analysis were performed. Also, gastrocnemius wet weight was measured. For pain assessment in group B, Rat Grimace Scale (RGS) score was used.

RESULTS

Significantly better functional recovery rate (using the SSI) was reported in the nerve lengthening group in comparison to autografting group. Also, a statistically significant higher nerve conduction velocity was detected in the nerve lengthening group. On histological analysis of the distal nerve section at 3 mm distal to the nerve repair site, significant myelin sheath thickness was detected in the nerve lengthening group.

DISCUSSION

Distraction neurogenesis with the new experimental device is a reliable therapeutic method for the reconstruction of nerve defects.

Chemotherapy-induced peripheral neuropathy after neoadjuvant or adjuvant treatment of breast cancer: a prospective cohort study

PURPOSE

The purposes of this study were to estimate the incidence of chemotherapy-induced peripheral neuropathy (CIPN) and to identify its main determinants and impact in patient-reported outcomes.

METHODS

We performed a prospective cohort study including 296 patients with incident breast cancer submitted to chemotherapy, followed for 1 year. Patients with incident CIPN were reevaluated 6 months after this diagnosis. Relative risks (RR) with 95 % confidence intervals (95 % CI) were computed to quantify the relation between different clinical characteristics and the occurrence of CIPN, using Poisson regression. The variation of patient-reported outcomes between baseline and 1-year follow-up assessments was compared between patients with and without CIPN.

RESULTS

The cumulative incidence of CIPN in the first year after diagnosis was 28.7 % (95 % CI 23.8-34.1), and more than 80 % of the patients were still symptomatic after 6 months. Among the latter, there was a significant decrease in the median total neuropathy score, clinical version (7 versus 4) between the two periods. In multivariable analysis, the risk of CIPN was higher for treatment with docetaxel (cumulative doses ≤300 mg/m(2), RR = 6.96, 95 % CI 2.53-19.10; >300 mg/m(2), RR = 13.32; 95 % CI 4.11-43.14). Alcohol consumption and diabetes were not significantly associated with CIPN. There were no significant differences in the variation of patient-reported outcomes between the baseline and 1-year follow-up evaluations.

CONCLUSIONS

CIPN was frequent in this contemporary cohort of early-stage breast cancer patients and was strongly associated with docetaxel-based regimens. Symptoms persisted for at least 6 months in most patients, but severity was low and CIPN had no impact on patient-reported outcomes.

Brachial Plexus Injury Caused by Indwelling Axillary Venous Pacing Leads

A 64-year-old male patient underwent cardiac resynchronization therapy (CRT) device implantation via the axillary venous approach. Two weeks later, the patient started complaining of "electric shock-like" pain in the left axillary area. During physical examination, typical pain in the left axillary area was reproduced whenever his left shoulder was passively abducted more than 60 degrees. Fluoroscopic examination showed that the left ventricle (LV) and right atrium (RA) leads were positioned at an acute angle directing towards the left brachial plexus whenever the patient's shoulder was passively abducted. Brachial plexus irritation by the angulated CRT leads was strongly suspected. To relieve the acute angulation, we had to adjust the entry site of the LV and RA leads from the distal to the proximal axillary vein using the cut-down method. After successful lead repositioning, the neuropathic pain improved rapidly. Although transvenous pacing lead-induced nerve injury is not a frequent complication, this possibility should be kept in mind by the operators.