Median Nerve Injury Research Articles

The epidermal growth factor receptor inhibitor gefitinib enhances in vitro and in vivo sensory axon regeneration and functional recovery following transection in a mouse median nerve injury model.

The epidermal growth factor receptor (EGFR; ErbB1), a membrane bound receptor tyrosine kinase, is hypothesized to have an inhibitory influence on peripheral nerve regeneration. This study examines the impact of EGFR inhibition on nerve regeneration using the commercially available small molecule inhibitor gefitinib. In vitro assays included neurite outgrowth of cultured dorsal root ganglion (DRG) neurons from adult C57Bl/6 wildtype mice on immobilized chondroitin sulfate proteoglycans (CSPG). Following forelimb median nerve injury, EGFR expression, number of regenerated neurons (using retrograde labeling) and myelination of motor and sensory neurons were compared between mice that received either gefitinib or vehicle. Functional recovery was assessed using grip strength. EGFR expression on DRG and spinal motor neurons was confirmed. Gefitinib significantly increased neurite outgrowth in medium sized (30-50 μm) DRG neurons, resulting in longer neurites (183 ± 36 μm) compared with CSPG alone (49 ± 9 μm). After median nerve injury, significantly greater numbers of sensory neurons (638 ± 112 vs. 301 ± 81), but not motor neurons (31 ± 12 vs. 42 ± 13) regenerated in animals treated with gefitinib compared with controls. Regenerated axons in gefitinib treated animals displayed significantly greater diameter and increased g-ratio compared with controls. Grip strength recovered more quickly in animals receiving gefitinib compared with controls (27.6 vs. 19.1 g 18 days post-injury). This study provides data supporting the role of EGFR as a negative regulator of sensory but not motor neuron regeneration. Further, it demonstrates versatile potential uses of existing pharmaceuticals.

Clinical effect of modified Henry approach in treating AO type B and C distal radius fractures

To investigate the clinical effect in treating AO type B and C distal radius fractures with modified Henry approach. Retrospectively analysis of 20 patients with AO type B and C distal radius fractures between June 2021 and May 2022, they were treated by modified Henry approach. There were 6 males and 14 females, aged from 35 to 78 years old, 8 patients on the left and 12 on the right. The patients' general data, fracture healing time, postoperative complications, last-time follow up radiographic parameters(volar inclination angle, ulnar deviation angle and radius height), wrist range of motion, range of forearm rotation and functional outcoming of the wrist joint according to Mayo scoring were observed of each patient. All patients were followed-up, the time was (13.3±2.3) months, ranged from 12 to 18 months. All the fractures were healed, the fracture healing time was (12.6±2.5) weeks, ranged from 10 to 16 weeks. There were no complications such as poor wound healing, incision infection, iatrogenic median nerve injury, delayed union, nonunion and malunion during the postoperative follow up. According to the X-ray measurement in the last-time follow up, the volar inclination angle was (11.4±4.0) °, the ulnar deviation angle was (20.9±2.2) ° and the radius height was (10.3±1.2) mm. The wrist range of motion was (65.3±5.8) ° for volar flexion, (60.2±4.2) ° for dorsal extension, (37.8±4.1) ° for ulnar deviation, (27.0±3.7) ° for radial deviation. The range of forearm rotation was(80.4±4.1) ° for pronation, (78.6±3.7) ° for supination. According to Mayo scoring, the wrist function was evaluated as excellent in 12 cases, good in 6 cases and fair in 2 cases, the excellent and good rate was 90%. Modified Henry approach can better expose the ulnar and volar fragments in distal radius, especially useful for reducting the distal radius with complex bi-columnar fractures.

Distal biceps tendon repair: outcome and complications with single incision anchor fixation.

The purpose of this study is to evaluate the functional outcome and quality of life in distal biceps tendon repair with single incision technique and anchor fixation method. A retrospective cohort study was made of patients with complete distal biceps tendon rupture. The chosen repair method was single incision technique with anchor fixation. The outcome was assessed with functional testing of the elbow with strength and ROM. Additionally Mayo elbow performance index, Oxford elbow score, Disability arm hand shoulder questionnaire and patient rated elbow evaluation scores were used to evaluate quality of life. Of the 28 patients, the average strength in flexion and supination was decreased with 91% and 89% of the strength compared to the non-injured arm. ROM was preserved in flexion, extension, supination and pronation. The mean scores for quality of life evaluation were MEPS = 96 ± 7.8, OES = 46.8 ± 1.9, DASH = 1.0 ± 1.9 and PREE = 2.0 ± 3.6. LABCN injury was the most common temporary complication with 30% followed by pain with 23%. Two patients were identified with HO and 1 patient was identified with median nerve injury. There were no cases of radioulnar synostosis and PIN injury. Overall strength in flexion and supination were slightly decreased with preserved ROM. Patients reported nearly perfect quality of life as demonstrated with the scores. The complications rate was high with mainly minor complications. Distal biceps tendon repair with single incision technique and anchor fixation overall leads to a very satisfying outcome.

Carpal tunnel release under local anesthesia with or without distal median nerve block: Double-blind randomized clinical trial

Background: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy of the upper extremity, and its surgical treatment is carpal tunnel release (CTR). It is mostly performed in local anesthesia. There are no clinical randomized controlled trials (RCTs) comparing local infiltration anesthesia with or without a distal median nerve block in CTR. The aim of the PERSONNEL trial (carPal tunnEl ReleaSe lOcal iNfiltratioN mEdian bLockade) is to assess whether a distal median nerve block reduces pain during and after the procedure in addition to local anesthesia. Methods: This is a single-center randomized clinical superiority trial comparing local anesthesia alone and local anesthesia with a distal median nerve block for CTR in patients with CTS. Adult patients will be randomized in one university hospital in Finland, and the intended sample size is 118. The primary outcome is the mean pain level after the procedure during 72 h using a visual analogue scale (VAS). The secondary outcomes include expected pain; pain during the injection of the anesthetic solution caused by pressure, burning, needle sting, and total pain; worst pain during the surgery; duration of anesthesia; number of experienced needle stings; Boston Carpal Tunnel Syndrome Questionnaire (BCTSQ); pain killer consumption;, patient satisfaction using Net Promoter Score (NPS); and complications. Discussion: Patient satisfaction is a crucial factor in modern healthcare. A distal median nerve block may reduce pain during and after CTR, potentially increasing patient satisfaction with the given treatment. It can also be hypothesized that better postoperative pain control may prevent complications, for example, complex regional pain syndrome. However, we lack adequate evidence to justify the use of distal median nerve block, which can itself predispose patients to complications, for example, median nerve injury. Therefore, there is a need for adequate RCTs to assess its efficacy. The results of this study can be used to optimize anesthesia for carpal tunnel surgery, improve patient satisfaction, and possibly prevent complications. Registration: ClinicalTrials.gov NCT05372393.

Median nerve lesions in pediatric displaced supracondylar humerus fracture: A prospective neurological, electrodiagnostic and ultrasound characterization.

Supracondylar humerus fractures (SCHFs) are the most common elbow fractures in children. Traumatic median nerve injury and isolated lesions of its pure forearm motor branch, anterior interosseus nerve (AIN), have both been independently reported as complications of displaced SCHFs. Our main objectives were to characterize the neurological syndrome to distinguish median nerve from AIN lesions and to determine the prognosis of median nerve lesions after displaced SCHFs. Ten children were prospectively followed for an average of 11.6 months. Patients received a standardized clinical examination and high-resolution ultrasound of the median nerve every 1-3 months starting 1-2 months after trauma. Electrodiagnostic studies were performed within the first 4 months and after complete clinical recovery. All children shared a clinical syndrome with predominant but not exclusive affection of AIN innervated muscles. High-resolution ultrasound uniformly excluded persistent nerve entrapment and neurotmesis requiring revision surgery but visualized post-traumatic median nerve neuroma at the fracture site in all patients. Electrodiagnostic studies showed axonal motor and sensory median nerve neuropathy. All children achieved complete functional recovery under conservative management. Motor recovery required up to 11 months and differed between involved muscles. It was shown that neurological deficits of the median nerve in displaced SCHFs exceeded an isolated AIN lesion. Notably, detailed neurological follow-up examinations and sonographic exclusion of persistent nerve compression were able to guide conservative therapy in affected children. Under these conditions the prognosis of median nerve lesions was excellent despite severe initial deficits, development of neuroma and axonal injury.

Infectious wrist arthritis complicating acute carpal tunnel syndrome in a child: A CARE-compliant case report.

The objective of this case report is to provide clinical evidence that acute infectious wrist arthritis in children can lead to the rare condition of acute carpal tunnel syndrome (ACTS). This article discusses in detail the characteristics of infectious wrist arthritis complicating ACTS in children in terms of etiology, pathogenic bacteria, treatment modalities, and sequelae to improve the understanding of this disease. A 10-year-old male child presented with a 15-day history of swelling and pain in the left forearm, wrist, and hand. Left-sided infected wrist arthritis complicating ACTS. The child received emergency surgery and anti-infective treatment combined with regular rehabilitation. During the treatment period, the child's wrist pain and swelling gradually improved, and wrist movement was restored compared with the preoperative period. At 6-month follow-up, the activities of the metacarpophalangeal joints of the left hand were close to normal, and the flexion of the left wrist joint was slightly limited. In infectious wrist arthritis in children, ACTS is a serious complication that requires aggressive surgical carpal tunnel release to avoid median nerve injury in addition to anti-infective therapy.

Application of external fixator combined with Kirschner wire fixation for oblique and comminuted distal humeral metaphyseal-diaphyseal junction fractures in children

To analyze the effectiveness of external fixator combined with Kirschner wire (EF-KW) fixation in the treatment of oblique and comminuted distal humeral metaphyseal-diaphyseal junction (DHMDJ) fractures in children. A clinical data of 22 children with DHMDJ fractures who met the selection criteria between April 2021 and December 2023 was retrospectively analyzed. All patients were treated with EF-KW fixation. There were 14 boys and 8 girls with an average age of 6.8 years (range, 1.5-12.0 years). The time from injury to operation was 14-38 hours (mean, 24.2 hours). There were 18 cases of comminuted fractures and 4 cases of oblique fractures; and 1 case of median nerve injury and 1 case of radial nerve injury before operation. The occurrence of postoperative complications was recorded. At last follow-up, the function of the affected elbow joint was evaluated according to the Mayo elbow joint function score, and the Baumann's angle (BA) and humero-capitellar angle (HCA) of the affected and healthy sides were recorded and compared. All fractures were successfully treated with closed reduction and no complications such as nerve injury occurred. Superficial infection occurred in 4 cases after operation and healed after symptomatic treatment. The incisions of other patients healed by first intention. All patients were followed up 9-24 months (mean, 13.8 months). At last follow-up, according to the Mayo elbow joint function score, the elbow joint function was rated as excellent in 15 cases, good in 6 cases, and fair in 1 case, with an excellent and good rate of 95.5%. The neurologic injury before operation recovered gradually. X-ray films reexamination showed that all fractures healed, and the healing time of fractures ranged from 29 to 61 days, with an average of 35.6 days. At last follow-up, there was no significant difference in BA and HCA between the healthy side and the affected side ( P>0.05). During follow-up, 1 case developed mild cubitus varus, while the other patients had no serious complications. EF-KW fixation for oblique and comminuted DHMDJ fractures in children has the advantages of less trauma, simple operation, easy reduction, good stability after reduction, low incidence of serious complications, and good elbow functional recovery.

Visualization of Median Nerve Entrapment After Reduction of an Elbow Fracture Dislocation Using 3-Dimensional Magnetic Resonance Imaging: A Case Report.

A 10-year-old girl presented after closed reduction of an elbow fracture dislocation. She demonstrated intact vascularity but a dense median nerve palsy. Preoperative magnetic resonance neurography (MRN) precisely mapped the median nerve entrapped within the medial epicondylar fracture. Intraoperatively, the median nerve was freed preceding reduction and fracture fixation. Postoperatively, neurological symptoms completely resolved, and she regained full elbow function. Median nerve injury can present without associated vascular injury. In this case, MRN was helpful in preoperatively illustrating the spatial relationship between the median nerve and the medial epicondyle.

Iatrogenic Median and Ulnar Nerve Damage Accompanying Acute Spinal Cord Ischemia

Peripheral arterial catheterization can be performed for hemodynamic monitoring during major cardiovascular operations. Different neurologic and cardiovascular complications may develop depending on the site of intervention. Peripheral nerve injuries are a rare complication of these catheterizations. Herein, we report median and ulnar nerve injury due to axillary catheterization in a patient with paraplegia due to spinal cord ischemia and rehabilitation results.

Endoscopic Versus Open Treatment of Carpal Tunnel Syndrome: Postoperative Complications in Patients With Diabetes Mellitus

Patients with type 2 diabetes mellitus (T2DM) often face higher postoperative complication rates. Limited data exist regarding outcomes in T2DM patients undergoing carpal tunnel release (CTR). This study compares complication rates between endoscopic CTR (ECTR) and open CTR (OCTR) in patients with T2DM. The TriNetX database was used to perform a retrospective cohort study of 67,225 patients with T2DM who underwent ECTR (n= 17,792) or OCTR (n= 49,433). Demographic data, medical comorbidities, and complication rates were analyzed. A 1:1 propensity score match was performed to calculate risk ratios and 95% confidence intervals of postoperative median nerve injury, 6-week wound dehiscence, and 6-week wound infection. After matching, a significantly greater number of ECTR patients had liver disease (P= <.001) and a body mass index > 40 (P= .001) compared to the OCTR group. These patients also had a lower incidence of fluid and electrolyte disorders (P= .003). Patients with T2DM who underwent ECTR had a significantly lower relative risk of 6-week wound infection, 6-week wound dehiscence, and median nerve injury (all P < .001) compared to patients who underwent OCTR. In our analysis of T2DM patients undergoing CTR, ECTR yielded significantly lower rates of wound infection, wound dehiscence, and nerve injury within 6-weeks post-surgery, reducing the risk by 43%, 52%, and 58%, respectively. These findings suggest that ECTR may result in a lower complication rate in this patient population. III.

Changes in ulnar and median nerve conduction velocity after reverse total shoulder arthroplasty: Correlation with distalization and lateralization

PurposeThe purpose of this study was to assess ulnar and median nerve injury after reverse total shoulder arthroplasty (RSA) by measuring the sensory nerve conduction velocity (SCV). The secondary objective was to evaluate the impact of lateralization and/or distalization on SCV changes. MethodsTwenty consecutive cases were prospectively included and retrospectively reviewed. SCV of the ulnar and median nerves as well as humeral lateralization/distalization quantified by plain radiography were evaluated pre-operatively and at 1 week post-operatively. Changes in SCV were tested using the paired t-test, and correlations between humeral lateralization/distalization and SCV changes were tested using Kendall's rank correlation coefficient and maximal information coefficient (MIC). ResultsThe SCV of the ulnar nerve was delayed from 55.4 ​m/s pre-operatively to 53.0 ​m/s post-operatively (p ​= ​0.021), whereas there was no significant change in the median nerve (p ​= ​0.17). There was a weak to moderate correlation between ulnar nerve SCV delay and lateralization (τ ​= ​−0.38; p ​= ​0.021; MIC ​= ​0.70) but no significant correlation with distalization (p ​= ​0.65; MIC ​= ​0.56). ConclusionsFollowing RSA, a small but significant delay in SCV of the ulnar nerve was observed. A negative correlation was found between lateralization and SCV delay of the ulnar nerve.

455 Distal Nerve Transfers in Treatment of Peripheral Nerve Lesions

INTRODUCTION: Distal nerve transfers can be used in treating patients with irreparable high nerve lesions, aiming to regain hand function. The indications for these transfers include upper (C5-C6) and lower (C8-T1) brachial plexus palsy, isolated proximal extensive radial, median, or ulnar nerve lesion, or isolated axillary or musculocutaneous nerve lesion. METHODS: The selected cases (n = 5) included lower brachial plexus injury (n = 2), and isolated radial (n = 1), ulnar (n = 1), and median (n = 1) nerve injuries. The MRC grading was used to examine postoperative muscle strength. The DASH and PNSQoL questionnaires were used to assess the postoperative quality of life. RESULTS: The useful functional recovery (MRC = 4-5) was achieved in all presented cases. The DASH and PNSQoL scores indicated a satisfying quality of life in terms of the absence of postoperative disability. CONCLUSIONS: Distal nerve transfers are a valuable technique for treatment of the patients with irreparable proximal nerve lesions. This technique reduces the path necessary for the regenerative nerve fibers to pass, provides direct nerve coaptation without additional suture line, and facilitates faster and better recovery, with the final outcome as an increase in the patients’ quality of life.

Ultrasound-Guided, Mid-Forearm Median Nerve Block for Relief of Carpal Tunnel Syndrome Pain in the Emergency Department: A Case Report.

Carpal tunnel syndrome (CTS) is a common complaint in the emergency department (ED) and accounts for approximately 90% of all peripheral neuropathies.6 Pain control from injection with corticosteroids into the carpal tunnel space is associated with multiple possible complications including atrophy, iatrogenic median nerve injury, and skin changes. Ultrasound (US)-guided mid-forearm median nerve block is an ED procedure that can be used to avoid direct injection into the carpal tunnel space. Here we present a case report proposing the use of US-guided mid-forearm block as a safe and effective adjunct to the management of acute pain caused by CTS. A previously healthy 44-year-old, right-hand dominant female presented to the ED with left wrist pain. Her clinical exam and US findings were consistent with CTS. Given her allergy to non-steroidal anti-inflammatory drugs, she was offered a median nerve block, which was performed in the ED. The patient reported continued pain relief 24 hours after discharge from the ED. There is limited data on the use of US-guided mid-forearm median nerve block as an acute pain management tool for CTS in the ED. The US-guided median nerve block done in the mid-forearm location can provide pain control for those with CTS while reducing the risk of complications associated with direct carpal tunnel injection.

Entrapment of median nerve after elbow fracture dislocations: expected surgical time frame based on cadaver study.

Median nerve injuries occur in approximately 3% of pediatric elbow fracture dislocations. These rare injuries can be difficult to diagnose, and the results are poor in delay cases. Surgical timing is one of the most important prognostic factors. We aimed to present three patients with median nerve palsy who were referred to our clinic late, and according to these cases, we emphasized the expected time frame for exploration based on our anatomical cadaver study. Between 2008 and 2010, three patients were referred to our clinic because of median nerve paralysis after a treated elbow dislocation. The mean interval between injury and referral was 15 (min: 13-max: 18) months, and the mean age of the patients was 15 (13-18) years. Neurolysis was performed in two patients, and for the third patent, after neurolysis, axonal continuity was observed to be disrupted so sural nerve grafting was performed with four cables. Tendon transfers were performed in all patients. A total number of 20 upper extremities of 10 cadavers were dissected. Due to its proximal innervation and ease of assessment, the muscle innervation of the flexor pollicis longus (FPL) was planned to be evaluated. The distance from the medial epicondyle is calculated in the cadaver study where the nerve injury is found. The mean length from the medial epicondyle to the motor innervation of FPL was calculated in each specimen and found to be 101.99 millimeters (mm) (range: 87.5-134.2). The mean longest innervation of FPL was 110.83 mm from (range 87.5-148.1) the medial epicondyle calculated by including each specimens longest nerve length. Knowing that the healing time of a nerve lesion is 1 mm per day, we calculated that the recovery of FPL would take approximately 4 months. When nerve healing is expected to be 1 mm a day in axonotmesis type injury, after the median nerve palsy following elbow dislocation, thumb flexion should be achieved in the following 4 months generally if the nerve was not entrapped in the joint. This cadaver-based study objectively defined how long to wait for the innervation of the FPL in median nerve injuries in elbow fracture dislocations.

Increased Risk of Coronary Artery Disease in People with Diagnosis of Neuromuscular Disorders: A Nationwide Retrospective Population-Based Case-Control Study.

The existing literature has explored carpal tunnel syndrome (CTS) and determined that it could be a risk for coronary artery disease (CAD), but there has been little research comparing the relevance of CAD with other neuromuscular disorders (NMDs) to CTS. This case-control study explored the association between CTS, stenosing tenosynovitis (ST), and ulnar side NMDs and CAD. The study utilized data from Taiwan's National Health Insurance Research Database, focusing on health insurance claims. Between January 2000 and December 2011, we employed the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic codes to identify 64,025 CAD patients as the case group. The control group consisted of an equal number of individuals without CAD, matched for age, sex, and index year of CAD. Logistic regression analysis was employed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for each variable. Multivariate analysis, after adjusting for sociodemographic factors and comorbidities, revealed a significantly higher likelihood of a previous diagnosis of CTS in the CAD group compared to the comparison control group. However, neither ST nor the ulnar side NMDs had any statistical significance. These results indicated that median nerve injury, rather than other NMDs, may uniquely serve as a predisposing factor of CAD.

Causes of Iatrogenic Median Nerve Injury after Endoscopic Carpal Tunnel Release.

Background: Endoscopic carpal tunnel release (ECTR) is a less invasive procedure but has a higher risk of complications. We analysed ECTR cases dividing them into three periods according to a single surgeon's experience when the ECTR was performed: the initial, midterm and late period. Cases of iatrogenically induced median nerve injuries that occurred after ECTR were then noted and evaluated. Methods: We reviewed 195 ECTRs done with the 2-portal technique and divided the patients into three groups according to periods of when ECTR was done. The indications for ECTR surgery were limited to severe CTS cases. These groups of patients were similar in terms of age, duration of disease, electrophysiological study results and severity of the disease. The patients were evaluated for median neuropathy pre- and postoperatively using Semmes-Weinstein monofilament test (SWT), Disabilities of the arm, shoulder and hand (DASH) Score, Coin-flip test (CFT), postoperative paraesthesias and complications, such as pillar pain, and so on. Electrophysiological evaluation was performed only preoperatively. Results: Postoperative median nerve recovery was overall good. Normal recovery was noted in 181 cases (93%). SWT, DASH and CFT were all significantly improved upon follow-up in all three groups. In terms of iatrogenic neuropathy, median nerve palsy worsened (including those transiently worsened) after ECTR in 11 cases (5.6%), even in the later period. The sensory disturbance was equally worsening from the radial to the ulnar side. Conclusions: The fact that there were neurologically worsened cases even in the later period, when the operator is higher skilled in the technique, suggests that the surgical technique itself may be the one posing higher risk than the level of surgical skill. The most likely causes of aggravated nerve palsy were a direct injury by cannula insertion at the proximal portal, or additional median nerve compression during cannula insertion into the carpal tunnel. Level of Evidence: Level IV (Therapeutic).

Comparative analysis of open versus endoscopic carpal tunnel release in a comprehensive national database

PurposeCarpal tunnel syndrome is the most common compressive neuropathy. There is limited evidence to support endoscopic compared to open carpal tunnel release according to the 2016 American Academy of Orthopaedic Surgeons Clinical Practice Guideline on carpal tunnel syndrome. The purpose of the present study was to assess differences between the two procedures by comparing 30- and 90-day complications and mean hospital costs in a large patient population. MethodsUsing the national Mariner15 Database by PearlDiver Technologies, we retrospectively studied 27,192 carpal tunnel syndrome patients who received carpal tunnel release using an endoscopic or open surgical approach from 2010 to 2019. Patients who met the inclusion criteria were grouped and case-matched at a 1:1 ratio through the corresponding International Classification of Diseases codes (n = 13,596) and assessed for 30- and 90-day complications such as median nerve injury, superficial palmar arch injury, and revision carpal tunnel release surgery. Univariate analysis was used to compare outcomes and a multivariate regression was performed to identify risk factors associated with each outcome. ResultsEndoscopic carpal tunnel release was associated with a higher rate of median nerve injury than open release at 30 days (0.3% vs. 0.1% odds ratio, 2.21; 95% confidence interval, 1.29–3.81; p < 0.05) and 90 days (0.4% vs. 0.3%; odds ratio, 1.77; 95% confidence interval, 1.16–2.70; p < 0.05). Endoscopic release was also associated with a higher rate of superficial palmar arch injury (0.1% vs. 0%; odds ratio, 25.02; 95% confidence interval, 1.48–423.0; p < 0.05). ConclusionsIn the present study, risk of median nerve injury and vascular injury was higher after endoscopic than open carpal tunnel release. At 90 days, all-cause revision rates were similar between techniques. Surgeons should understand these differences, to optimize surgical decision-making. Level of evidenceTherapeutic, IIIa.

Transfer of the palmaris brevis motor branch to the thenar motor branch: A cadaveric preliminary study

ObjectiveHigh median nerve injuries can lead to poor distal recovery, especially poor functioning of median innervated thenar muscles involved in thumb opposition and palmar abduction. The palmaris brevis (PB) is a small subcutaneous muscle innervated by ulnar nerve. Innervation of the PB is in most of cases provided by the ulnar digital nerve to the little finger. The purpose of this study is to assess the feasibility of transferring the PB motor branch (PBMB) to the median nerve thenar motor branch (TMB), in order to allow for early restoration of thumb palmar abduction and opposition, through a preliminary cadaveric study. MethodsTwenty-five cadaver upper limbs were dissected under magnification. The length of the PBMB and TMB, and their origin were recorded. Nerve transfer from PBMB to TMB was conducted, and evaluated on 2 parameters: surgical feasibility, and distance from the coaptation site to the recipient nerve muscle entry point. The PBMB and TMB were harvested, fixated in formalin, then embedded in paraffin. They were sectioned transversely, and stained with a combination of hematoxylin–eosin and Luxol fast blue. Myelinated axons were counted in each specimen and the donor-to-recipient axon ratio was recorded. ResultsThe PBMB was constant and originated from the ulnar digital nerve of the little finger in all cases. The transfer from PBMB to TMB was feasible in all cases. Mean myelinated axon counts of PBMB and TMB were 253±142 and 356±198, respectively (p=0.06). The donor-to-recipient axon ratio was 1:1.41. The mean distance from coaptation of the PBMB to the recipient thenar muscles was 23.1±3.0mm. ConclusionsBased on our results, PBMB to TMB transfer is feasible. The PBMB has the advantage over other distal nerve transfer donors to be constant and superficial, allowing for an easier harvest. Moreover, this procedure does not sacrifice any intrinsic function of the hand, and the proximity of the PBMB with the carpal tunnel allows for a single incision procedure. Therefore, early restoration of the median innervated thenar muscles may be feasible by the PBMB to TMB transfer in cases of high median nerve lesions. Level of evidenceIV.

Clinical Application of Ultrasound-guided Electrode Placement and Detection of Nerve Action Potential.

We explore a minimally invasive method (combined ultrasound detection, electrode placement and electrophysiologic nerve examination) to evaluate the early-stage quality of a nerve suture site. Ten patients with median and/or ulnar nerve injuries who had undergone nerve suture were recruited. Postoperative ultrasound examination found that the nerve injury was sutured. Then, a stimulating electrode and recording electrode were located beside the nerve proximal and distal to the suture site guided by ultrasound. Measurement of nerve action potentials (NAP) were performed with these electrodes, followed by surgical exploration. The pre- and intraoperative electrophysiologic findings were compared, together with amplitude, latency, and wave shape of NAP. Of the 10 patients, 3 patients were diagnosed with median nerve injury, 2 with ulnar nerve injury, and 5 with the median nerve and ulnar nerve injury. NAP could not be detected pre- and intraoperatively in three median nerves from three patients and in two ulnar nerves from two patients. NAP was detected in 10 nerves from the remaining 5 patients. The pre- and intraoperative NAP results showed consistent results concerning the status of the nerve suture. Wilcoxon's signed-rank test indicated no significant difference in the amplitude and latency detected via sonographically placed electrodes and during surgical exploration. The number of negative-phase waves were equally distributed. Ultrasound-guided electrode placement and NAP detection can substitute surgery and serve as a minimally invasive approach to evaluate the regeneration of a sutured nerve.

Updates in peripheral nerve surgery of the upper extremity: diagnosis and treatment options.

The loss of function resulting from peripheral nerve injuries confers a significant burden to the patient and society. The treatment of peripheral nerve injuries requires an accurate diagnosis and formulation of a functional reconstructive plan. Advances in peripheral nerve imaging complement electrodiagnostic studies, and provide us with detailed information regarding the status of nerve injury, repair, and regeneration in order to prognosticate recovery and determine the need for surgical intervention. When direct nerve repair is not possible, the methods for bridging a nerve gap are the nerve autograft, allograft and conduit. While current research supports the use of conduits and nerve allografts for shorter nerve gaps, the nerve autograft still remains the gold standard for bridging a nerve gap. When direct nerve repair or nerve grafting fails, or is anticipated to be insufficient, nerve transfers are an alternative for reconstruction. Knowledge of axonal counts, upper limb innervation patterns, location and clustering of upper limb peripheral nerves allows for the design of new nerve transfers. The options of nerve transfers for radial, ulnar and median nerve injuries are outlined, as well as their outcomes. Nerve transfers are an attractive option for restoring motor and sensory function while minimizing donor site morbidity. However, one must consider their limitations, and preserve donor sites for secondary tendon transfer options. This article presents the latest information regarding the imaging of peripheral nerves, methods to bridge a nerve gap, and nerve transfers to aid the peripheral nerve surgeon in choosing a reconstructive plan.