Ulnar Nerve Research Articles

The Efficacy of Combined Decompression of Carpal and Cubital Tunnel in the Setting of Cervical Spine Stenosis: A Retrospective Analysis

The Efficacy of Combined Decompression of Carpal and Cubital Tunnel in the Setting of Cervical Spine Stenosis: A Retrospective Analysis

The Enigma of the Motor Nerve Conduction Study.

In motor nerve conduction studies (MNCS), proximal stimulation should give a longer duration and lower amplitude compound muscle action potential (CMAP) due to higher temporal dispersion. Yet the CMAP waveforms at the distal and proximal stimulation sites appear remarkably similar. The objective of this study was to confirm this anomaly and investigate its possible cause by studying the median and ulnar nerves. Recordings from 50 subjects with normal electrodiagnostic studies were reviewed. The conduction velocity (CV) was measured using different points on the negative phase of the CMAP including its peak and baseline crossing. Collision studies were performed in three healthy subjects to measure the dispersion when nerve action potentials (APs) propagated from elbow to wrist. CV was relatively unaffected by the measurement point on the CMAP. The CMAP duration with elbow stimulation increased minimally compared to wrist stimulation. This was inconsistent with the dispersion of the AP from wrist to elbow measured in collision studies. The insignificant change in the CMAP in spite of axon AP dispersion is an enigma. We hypothesize that the terminal conduction time (TCT) (i.e., conduction in terminal axon branches, neuromuscular transmission, etc.) is independent of axon CV, represents a significant portion of the latency, masks AP dispersion, and reduces CMAP dispersion. This yields similar CMAPs with distal and proximal stimulation. The onset latency at the distal stimulation site does not depend on CV. Thus, onset latency and CV may not reflect the conduction properties of the fastest conducting axons.

Contribution of remote Pacinian corpuscles to flutter-range frequency discrimination in humans.

Among the various classes of fast-adapting (FA) tactile afferents found in hairy and glabrous skin, FA2 afferents, associated with Pacinian corpuscles (PC), preferentially signal high-frequency sinusoidal events corresponding with vibration percepts, in contrast to other classes associated with lower frequency flutter percepts. The FA2-PC complex is also uniquely sensitive to distant sources of vibration mechanically transmitted through anatomical structures. In the present study, we used a pulsatile waveform to assess the contribution of FA2 afferents to the perception of flutter-range frequency stimuli (~ 20Hz) in combination with two methods to abolish local FA inputs and force a dependence on FA2 via transmission from adjacent structures. Firstly, we examined frequency discrimination and perception of vibration applied to the hairy skin overlying the ulnar styloid before and during the blockade of intradermal receptors by local anaesthesia. Secondly, we tested frequency discrimination on the digital glabrous skin before and during the blockade of myelinated fibres by ulnar nerve compression. Despite reliance on vibration transmission to activate remote PCs, we found that flutter-range frequency discrimination was unimpeded across both skin types. Comparisons with stimuli applied to the contralateral side also indicated that perceived frequency was unaffected. This confirms that flutter-range frequency perception can be encoded by the FA2-PC system. Our results demonstrate that input from receptors specialised for low-frequency signalling is not mandatory for flutter-range frequency perception. This explains how the constancy of frequency perception might be achieved across different skin regions, irrespective of the afferent type activated for transmitting these signals.

Recurrent Ulnar Nerve Schwannoma in the Cubital Tunnel Elbow: A Rare Presentation and Surgical Management

Recurrent Ulnar Nerve Schwannoma in the Cubital Tunnel Elbow: A Rare Presentation and Surgical Management

Sural-to-medial femoral cutaneous amplitude ratio in early diagnosis of uremic neuropathy.

Medial femoral cutaneous (MFC) sensory nerve action potentials (SNAPs) can be easily recorded using distal stimulation. This study aimed to identify a new parameter using MFC SNAPs for the early electrophysiological diagnosis of length-dependent axonal polyneuropathy (LDAP) associated with uremic neuropathy. Patients with chronic renal failure who were referred to the electrodiagnostic laboratory due to symptoms suggesting polyneuropathy were included. Assessments encompassed neurological examination, Michigan Neuropathy Screening Instrument (MNSI), and Semmes-Weinstein monofilament test. Antidromic radial, median, ulnar, MFC, sural, and superficial peroneal sensory; median, ulnar, tibial, and peroneal motor nerve conduction studies were performed. Sural-to-radial amplitude ratio (SRAR) and sural-to-medial femoral cutaneous amplitude ratio (SMFCAR) were calculated, and their diagnostic sensitivities were compared with the age and sex matched healthy controls. Thirty-two chronic renal failure patients (mean age 60.0 ± 9.6 years) and 37 controls (60.6 ± 9 years) were included. MNSI indicated clinical polyneuropathy in 59.4% of patients, while sural SNAP amplitude was diagnostic in 78%. Median SRAR and SMFCAR values were significantly lower in patients than controls (p < .001 for both). The cut-off values for SMFCAR and SRAR were <1.82 and <0.30, respectively, both with a sensitivity of 59% and a specificity of 94%. Sural SNAP is the most sensitive parameter in the diagnosis of LDAP. SMFCAR is not superior to SRAR. If the sural SNAP amplitude is normal, SMFCAR can serve as an alternative to SRAR in dialysis patients with bilateral arteriovenous fistulae or in those unable to undergo radial NCS.

Early and Late Intrinsic Hand Muscle Reinnervation After End-to-Side AIN to Ulnar Motor Nerve Transfer.

The "supercharge" end-to-side (SETS) anterior-interosseous-nerve (AIN) to ulnar-motor nerve transfer is used to improve intrinsic muscle recovery in cases of severe ulnar nerve compression or proximal axonotmetic injuries. Previous work has found differing intrinsic muscle recovery after this transfer. The objectives of this study were to examine the patterns of recovery in first dorsal interossei (FDI) and abductor digiti minimi (ADM) and the impact of AIN transfer to a specific fascicular location on the ulnar-motor nerve. A retrospective review of one fellowship-trained surgeon's consecutive patients at a single center from December 2019 to September 2021 was conducted. Patients who had an AIN to ulnar-motor nerve transfer for any indication were included and were excluded if they had less than 9 months follow-up. Seventeen patients were included (88% male, mean age 55 ± 14 years). At early follow-up, compound muscle action potential amplitudes for ADM and FDI did not increase. Compound muscle action potential amplitude for ADM significantly increased at late follow-up (P < .01). Average British Medical Research Council (BMRC) strength increased at early follow-up for FDI (P < .05), but not ADM. The proportion of patients with BMRC ≥ 3 increased for FDI (P < .01) and ADM (P < .05) at late follow-up. Volar-ulnar AIN insertion position did not have a clear effect on outcomes. The SETS AIN to ulnar-motor nerve transfer demonstrates clinical and electrophysiologic evidence of intrinsic muscle recovery and reinnervation, with differing recovery of outcomes. The role of specific fascicular targeting is still unclear and required further examination as does the mechanism behind differing intrinsic recovering.

Clinical Features of Conduction Block in Ulnar Neuropathy at the Elbow: The Surgery of the Ulnar Nerve (SUN) Multicenter Clinical Trial.

In ulnar neuropathy at the elbow, weakness is classically a sign of severe disease. Weakness is associated with motor axonal loss as measured by decreased distal compound muscle action potential (CMAP) amplitude. Conduction block, a demyelinating phenomenon that recovers readily, can also cause weakness, creating ambiguity for the treating clinician. This cross-sectional study evaluated baseline blinded data collected from 2020-2023 from the Surgery of the Ulnar Nerve randomized controlled trial comparing in-situ decompression versus transposition procedures. Adult patients underwent electrodiagnostic testing, clinical motor and sensory testing, and completed the Michigan Hand Questionnaire and Carpal Tunnel Questionnaire. 177 patients were categorized into 3 distinct groups based on normal distal CMAP amplitudes (77 patients), presence of conduction block with or without distal CMAP amplitude loss (37 patients), or pure axonal loss with distal CMAP amplitude loss in the absence of conduction block (63 patients). Compared to the normal group, patients with conduction block had significantly decreased pinch strength and worse function domain scores on the Michigan Hand Questionnaire and Carpal Tunnel Questionnaire, but shorter duration of disease. Patients with pure axonal loss had decreased pinch strength, worse 2-point discrimination, and worse overall, function and aesthetics domain scores on the Michigan Hand Questionnaire. There was a significant interaction between the effects of conduction block and distal CMAP amplitude on pinch strength, indicating that higher degrees of conduction block resulted in more pronounced loss of pinch strength in patients with relatively preserved distal CMAP amplitude. Our findings support the paradigm that ulnar neuropathy at the elbow presenting with conduction block represents a distinct and intermediate pathophysiology, distinguished by quicker onset with less advanced neurological deficits. Prognostic Level II.

Is anterior transposition of the ulnar nerve necessary for post-traumatic elbow stiffness? A retrospective study

ObjectiveTo explore whether anterior transposition of the ulnar nerve is necessary in patients with post-traumatic elbow stiffness.MethodThis was a retrospective study of 177 patients with post-traumatic elbow stiffness treated at Shandong Provincial Hospital from 1 January 2012 to 31 October 2022. Sixty-one patients presented with ulnar nerve symptoms, and 116 patients had no nerve symptoms. Outcomes between patients with and without symptoms were compared using a range of clinical measures, namely range of motion (ROM), ulnar nerve symptoms, and various standardized scoring systems, namely, the Mayo Elbow Performance Score (MEPS), visual analog scale (VAS), improved Broberg and Morrey Score (BMS), Quick disabilities of the Arm, Shoulder, and Hand (DASH) score, Oxford Elbow Score (OES), and Amadio score.ResultsOpen elbow release surgery significantly improved elbow joint function in patients with post-traumatic elbow stiffness, regardless of the presence of ulnar nerve symptoms. Patients with ulnar nerve symptoms showed significant improvement after anterior transposition compared with in situ release. For patients without ulnar nerve symptoms, there was no significant difference in outcomes between the two types of ulnar nerve surgery.ConclusionAnterior transposition of the ulnar nerve is preferable for patients with ulnar nerve symptoms, while the choice between anterior transposition and in situ release can be individualized for patients without symptoms, based on intraoperative findings.

Fiber anatomy and histological characteristics of the innervation of the triangular fibrocartilage complex.

To evaluate the precise origin of sensory nerves through gross anatomical study of the TFCC, synthesized alongside imaging and histological techniques. Six cadaveric forearm specimens were obtained to map the course and branches of the ulnar nerve through macrodissection. Immunohistochemical staining targeting PGP 9.5 and type IV collagen was performed on frozen TFCC sections to visualize nerve fibers microscopically. Computed tomography, magnetic resonance imaging, and arthrography findings were also reviewed. At the macroscopic level, the articular branches supplying the TFCC originated predominantly from the dorsal branch of the ulnar nerve. Microscopic analysis revealed positive PGP 9.5 expression and discernible neural marker expression, signifying fine nerve fiber ingrowth within the TFCC. Imaging modalities aided the diagnosis of TFCC lesions. The dorsal cutaneous branch of the ulnar nerve, medial cutaneous nerve of the forearm, and volar sensory branch of the ulnar nerve emerged as the principal nerves innervating the TFCC. This study provides anatomical evidence that the TFCC receives innervation from branches of the ulnar nerve and contains sensory nerve fibers. These findings enhance understanding of potential neuropathic pain mechanisms in TFCC injuries and offer insights to guide surgical interventions. Further investigations are warranted to elucidate the clinical implications.

Clinical Cues for the Early Diagnosis of Transthyretin-Related Polyneuropathy.

The estimated prevalence of hereditary transthyretin-related familial amyloid polyneuropathy (TTR-FAP) and the small number of known patients in Germany indicate that many patients with TTR-FAP remain undiagnosed, and may instead be classified as "idiopathic." The aim of this study was to identify biomarkers for detecting TTR-FAP among a cohort of patients with idiopathic polyneuropathy (PNP). Clinical evaluations (including the Neuropathy Impairment Score and Neuropathy Disability Score), nerve conduction studies (NCSs), quantitative sensory testing, and autonomic function tests were performed on 23 patients with TTR-FAP and 89 with idiopathic PNP. Discriminant analysis was then performed to identify variables useful for predicting TTR-FAP. Patients with TTR-FAP had paresis of the finger and thumb muscles, and reduced vibration perception and increased pressure pain in the upper and lower extremities. The NCSs showed that action potentials were smaller in the median, ulnar (both motor and sensory), and sural nerves in TTR-FAP. The sensory nerve conduction velocity was also reduced in the ulnar nerve. Autonomic neuropathy was confirmed by reduced sympathetic skin responses in the hands and feet in TTR-FAP. Multivariate discriminant analysis revealed that finger abduction strength, sensory ulnar nerve action potential amplitude, and vibration detection and pressure pain thresholds in the upper extremities were sufficient to correctly identify TTR-FAP in 81.3% of cases. Detailed clinical and neurophysiological investigations of standard parameters in the upper limb may help to identify the otherwise-rare TTR-FAP.

Distal Mononeuropathy and Nerve Release After Open and Arthroscopic Shoulder Surgery: A Matched Cohort Analysis

The purpose of this study was to determine if patients who have undergone prior open or arthroscopic shoulder surgery and develop distal mononeuropathy (DMN) achieve the same clinical benefit after nerve release compared with those who did not have a prior shoulder procedure. Patients were identified by Current Procedural Terminology code for shoulder arthroplasty, shoulder stabilization, and rotator cuff repair and if they had an ensuing nerve release (cubital or carpal tunnel) within 2 years of shoulder surgery. Another cohort that underwent nerve release surgery for DMN with no prior history of shoulder surgery was identified and subsequently matched to the first cohort by a 3:1 (control:case) ratio. Patients were included if they were over the age of 18 years. Chart reviews and surveys stored using REDCap were used to collect demographics, surgical history, EMG/nerve conduction velocity results, postoperative symptoms, and patient-reported outcomes with a minimum 2-year follow-up. In total, 120 patients were included in this analysis (28 cases, 92 controls). The most common nerve release for DMN across both cohorts was open carpal tunnel release. Following nerve release, the case group had more postoperative persistent numbness/tingling than the control group. Both groups were similar with regard to postoperative pain, weakness, or patient-reported outcome measures. Residual postoperative numbness following nerve release was more likely to occur in the forearm for the case group than the control group. Patients with a history of arthroscopic rotator cuff repair and reverse total shoulder replacement shoulder surgery before the presentation of DMN are more likely to experience persistent numbness or tingling after nerve release surgery as well as experience symptoms in the forearm than those without prior shoulder surgery. Symptom prevalence retrospective study III.

Ultrasound-guided proximal radial, ulnar, median and musculocutaneous (RUMM) nerve block in rabbit (Oryctolagus cuniculus) cadavers: medial vs lateral approach

Ultrasound-guided proximal radial, ulnar, median and musculocutaneous (RUMM) nerve block in rabbit (Oryctolagus cuniculus) cadavers: medial vs lateral approach

Variations of the ulnar nerve within the ulnar tunnel and palm in a select South African population

Variations of the ulnar nerve within the ulnar tunnel and palm in a select South African population

Favorable Outcomes Following Elbow Ulnar Collateral Ligament Reconstruction and Repair, Though Repair Associated with Increased Risk of Revision Surgery

To assess the risk of revision surgery following repair versus reconstruction of the medial ulnar collateral ligament (UCL) of the elbow in a national sample of patients in the United States. This was a retrospective cohort study of young patients (≤35 years old) who underwent primary UCL reconstruction or repair for an isolated medial UCL injury of the elbow from October 2015 through October 2022 in a large national database (PearlDiver). Patient demographic data, comorbidities, surgical details, and concomitant ulnar nerve procedures were collected. Time-to-event analyses were used to assess the risk of revision UCL surgery between groups. Two-year complication rates, including ulnar neuropathy, were also assessed. In total, 1,820 patients (69.9% reconstruction, 30.1% repair) with an average follow-up of 2.9 years met inclusion criteria. The estimated 2-year revision-free survival (95% confidence interval [CI]) was 99.5% (99.1%-99.9%) for UCL reconstruction compared to 97.9% (96.4%-99.3%) for UCL repair (unadjusted Log-rank p=0.032). UCL repair remained associated with an increased risk of revision UCL surgery after adjusting for confounding variables (hazard ratio 2.94, 95% CI 1.07-8.09, p=0.037). Complication rates were similar between reconstruction and repair, including the incidence of ulnar neuropathy (13.8% vs. 14.5%, p=0.78). In this study, we found that UCL repair was associated with a significantly higher risk of revision UCL surgery than UCL reconstruction in a national sample. Importantly, however, overall failure rates were low and complication rates were similar between procedures. These findings support the overall favorable outcomes of UCL repair, while suggesting it may not necessarily be the optimal treatment for all patients. 3 - retrospective cohort study.

Reconstruction after proximal ulnar resection.

Reconstruction after osteoarticular resection of the proximal ulna for tumours is technically difficult and little has been written about the options that are available. We report a series of four patients who underwent radial neck to humeral trochlea transposition arthroplasty following proximal ulnar osteoarticular resection. Between July 2020 and July 2022, four patients with primary bone tumours of the ulna underwent radial neck to humeral trochlea transposition arthroplasty. Their mean age was 28 years (12 to 41). The functional outcome was assessed using the range of motion (ROM) of the elbow, rotation of the forearm and stability of the elbow, the Musculoskeletal Tumor Society score (MSTS), and the nine-item abbreviated version of the Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH-9) score. All patients were available for follow-up at a mean of 33 months (25 to 43) and were disease-free. The mean flexion arc was 0° to 105°. Three patients had complications. One had neuropraxia of the ulnar nerve. The symptoms resolved after three months. In one patient, the screw used for fixation of the triceps tendon became exposed and was removed, six months postoperatively. One patient with wound dehiscence required a local flap for soft-tissue cover, four months postoperatively. At a mean follow-up of 33 months (25 to 43), the mean flexion arc was 0° to 105°. All patients had full supination (85°) but none had any pronation. The mean MSTS score was 23.5 (23 to 24) and mean QuickDASH-9 score was 26.13 (16.5 to 35.75). Three patients had varus-valgus instability on examination, although only one had a sense of instability while working. Radial neck to humeral trochlea transposition offers a satisfactory and cost-effective biological reconstructive option after osteoarticular resection of the proximal ulna, in the short term. It provides good elbow function and, being a biological reconstruction option using native bone, is likely to provide long-term stability and durability.

Surgical Treatment and Outcomes of Trans-Ulnar Basal Coronoid Fracture-Dislocations

Trans-ulnar fracture-dislocations of the elbow are complex injuries that can be difficult to classify and treat. Trans-ulnar basal coronoid injuries, in which the coronoid is not attached to either the olecranon or the metaphysis, present substantial challenges to achieve anatomic reduction and stable internal fixation. The purpose of this study was to analyze the outcome of surgical treatment of trans-ulnar basal coronoid fracture-dislocations. Between 2002 and 2019, 32 consecutive trans-ulnar basal coronoid fracture-dislocations underwent open reduction and internal fixation (ORIF) at our institution. Four elbows were lost to follow-up within the first 6 months after surgery and were excluded. Among the 28 elbows remaining, there were 13 females and 15 males with a mean age of 56 (range 28-78) years at the time of injury. The mean clinical and radiographic follow-up times were 37 months and 29 months, respectively. Radiographs were reviewed to determine rates of union, Hastings and Graham heterotopic ossification (HO) grade, and Broberg and Morrey arthritis grade. Union occurred in 25 elbows. Union could not be determined for 1 elbow at most recent follow-up and the remaining 2 elbows developed nonunion of the coronoid. Complications occurred in 10 elbows (36%): deep infection (4), ulnar neuropathy (2), elbow contracture (2), and nonunion (2). There were reoperations in 11 elbows (39%): irrigation and débridement with hardware removal (4), hardware removal (2), ulnar nerve transposition (2), contracture release with HO removal (2), and revision ORIF with iliac crest autograft (1). At most recent follow-up, the mean flexion-extension arc was 106° (range 10-150°), and the mean pronation-supination arc was 137° (range 0-170°). The mean Quick Disabilities of Arm, Shoulder, and Hand score was 11 (range 0-39) points with a mean Single Assessment Numeric Evaluation-Elbow score of 81 (range 55-100) points. At final radiographic follow-up, 16 elbows (57%) had HO (8 class I and 8 class II), and 20 elbows (71%) had arthritis (8 grade 1, 6 grade 2, and 6 grade 3). Trans-ulnar basal coronoid fracture dislocations are severe injuries associated with high rates of reoperation, heterotopic ossification, and post-traumatic arthritis. However, the majority of elbows achieve union, a functional range of motion, and reasonable patient reported outcome measures. Over the study period, surgeons were more likely to utilize multiple deep approaches and separate fixation of the coronoid (either with lag screws or anteromedial plates) to ensure anatomic reduction.

Technique and Expected Benefit of Intraoperative Perfusion Imaging of Peripheral Nerves.

Peripheral nerve surgery, particularly in cases of nerve compression syndrome (NCS), necessitates a comprehensive evaluation of intraneural blood flow, as localized reductions in nerve perfusion are integral to the etiopathogenesis of such conditions. Although nerve perfusion is currently guided by morphologic characteristics, this assessment is subjective and prone to bias. Intraoperative fluorescence-assisted perfusion imaging with indocyanine green (ICG) is an established tool in flap and lymphatic surgery to objectively assess perfusion intraoperatively. However, only a few unspecific applications of ICG in peripheral nerve surgery have been published so far. In this study, we performed intraoperative perfusion imaging using ICG in 16 consecutive operations within the peripheral nervous system, including microsurgical reconstructions after obstetric brachial plexus injury, decompression for NCS, and vascularized ulnar nerve interposition transfers. Our findings show the utility of ICG in delineating healthy perfusion borders at proximal and distal stump levels after neuroma resection, and we demonstrate a correlation between histological findings and these clinically observed perfusion patterns. In NCS cases, we demonstrate that ICG imaging is effective in highlighting reduced perfusion predecompression and improved perfusion postdecompression. Additionally, ICG proved valuable for assessing perfusion of free vascularized nerve grafts. Intraoperative ICG perfusion imaging is a valuable tool during surgery of the peripheral nervous system, providing insights into the etiopathogenesis of NCS and aiding in the visualization of perfusion. This study underscores the potential of ICG in nerve surgery and its applicability for improving surgical outcomes and advancing our understanding of peripheral nerve pathologies.

Comparing scissors and scalpels to a novel surgical instrument: a biomechanical sectioning study

BackgroundThis study introduces a novel surgical instrument to reduce iatrogenic nerve injuries during procedures such as carpal tunnel and ulnar nerve decompression surgery. These injuries often result from direct damage to surrounding tissues by surgical instruments, whose designs have remained largely unchanged over the past decades. The novel device is a modified surgical forceps that has a deployable surgical scalpel that runs along a groove on the forceps. This design protects important anatomical structures while allowing fast dissection and cutting of fascial layers.MethodsThe process used to develop a novel instrument included computer-aided design (CAD) modeling, 3D printing for prototyping, and the fabrication of an aluminum prototype. Biomechanical testing was performed with the novel device, iris scissors, bandage scissors, and a scalpel on an MTS Static Materials Test System. The peak force to slide-cut, number of cut attempts, and percentage cut on first attempt were compared between the prototype and traditional surgical tools. The materials cut in testing were Ace™ bandage, stockinette, and gauze. Statistical analyses were performed using Welch’s t-tests and Fisher’s exact tests.ResultsCompared to conventional bandage and iris scissors, the novel surgical instrument required significantly less force to cut through an Ace™ bandage, stockinette, and gauze (p < 0.01). The number of cuts required to transect those same materials with the novel device was comparable to that of the scalpel and bandage scissors. Additionally, while there were no differences between the novel device and the other devices for an Ace™ bandage and stockinette, the novel device tended to cut a greater percentage of gauze in one pass than did the iris scissors.ConclusionThe novel surgical instrument designed in this study required less force compared to conventional scissors, demonstrated cutting efficiency similar to that of a scalpel blade, and had more safety features than either instrument. This study highlights the value of collaboration between biomedical engineering and orthopedic surgery departments on innovation in medical technology, through which new technologies with improved design and functionality demonstrate the potential to reduce iatrogenic injuries.

Ulnar Compression Neuropathy Secondary to Ganglion Cyst at the Elbow Joint: A Case Report

Ulnar neuropathy is a common peripheral neuropathy, with cubital tunnel compression being the second most frequent upper extremity compression syndrome. Ganglion cysts, though rare, can contribute to ulnar nerve compression in the cubital tunnel. Here, we present a case of a 62-year-old farmer with longstanding diabetes and dyslipidemia who experienced progressive pain and numbness in his medial fingers, exacerbated by elbow flexion. Initially misdiagnosed and treated for Hansen’s disease. Clinico-radiological evaluation revealed a multiloculated cystic lesion in the posteromedial aspect of his left elbow, compressing the ulnar nerve. Surgical excision of the ganglion cyst alleviated symptoms, though residual motor deficits persisted postoperatively. This case underscores the importance of considering ganglion cysts in the differential diagnosis of cubital tunnel syndrome, highlighting the diagnostic challenges and therapeutic considerations in managing this rare etiology.

Evaluation of Split Hand Syndrome in Early Diagnosis of Amyotrophic Lateral Sclerosis by Nerve Conduction Study as a Diagnostic Tool

Background: Amyotrophic lateral sclerosis (ALS), a degenerative disease of the motor neurons that can present diversly. Needle electromyography (EMG) is the gold standard investigation for the diagnosis of ALS. Split hand syndrome (SHS) demonstrated by nerve conduction study (NCS); a noninvasive tool could be useful in diagnosing ALS. This study aimed to assess SHS by NCS in ALS. Methods: This diagnostic accuracy case-control study included 37 cases of ALS and 37 age and gender-matched controls. Compound muscle action potential (CMAP) and distal motor latency (DML) of median and ulnar nerves and the ratio of median and ulnar CMAP and DML were compared between study groups. The diagnostic validity testing of electrophysiological SHS was also done. Results: The mean age of the ALS and control groups were similar, 39.8±2.7 and 39.3±2.6 years, respectively. Sixteen (43.2%) ALS patients were in 30-59 years age group. Male-female ratio was 5.2. In the ALS group, median-ulnar CMAP ratio was lower and median-ulnar DML ratio was prolonged than the control. The diagnostic efficacy of median-ulnar CMAP ratio and DML ratio were calculated. A median-ulnar CMAP ratio cut-off value ≤1 showed 70% sensitivity, 97% specificity, 96% positive predictive value and 77% negative predictive value. A median-ulnar DML ratio cut-off value ≥1.5 showed 48% sensitivity, 89% specificity, 82% positive predictive value and 65% negative predictive value. Conclusion: NCS demonstrating SHS can be an important tool in the early diagnosis of ALS. J Bangladesh Coll Phys Surg 2024; 42: 350-354