Cubital Tunnel Syndrome: Current Concepts

The Effects of Photobiomodulation Therapy in Cubital Tunnel Syndrome, Clinical Trial

Aim: We aimed to evaluate the effects of laser therapy together with rest splint and exercise on muscle strength, function, activities of daily living, and pain in individuals suffering from cubital tunnel syndrome (CuTS) by comparing it with placebo treatment. Materials and Methods: This prospective, single-blind, and randomized controlled study was conducted with 64 patients with CuTS in total. They were divided into two groups by randomization: Group 1 (n = 32) was provided with low-energy laser therapy + splint + exercise, and Group 2 (n = 32) was provided with low-energy sham laser therapy + splint + exercise. Patients in both groups received resting splints and nerve release exercises. Pretreatment and posttreatment (3rd week, 3rd month) evaluations were made with the Visual Analog Scale (VAS), the Quick Disability of Arm, Shoulder, and Hand Questionnaire, hand grip strength, fingertip grip strength, the Patient-Rated Ulnar Nerve Evaluation Scale (PRUNES), and Short Form-12. An electrophysiological evaluation was performed at baseline and at the 3rd month. Results: We observed significant improvements in both groups regarding pain, function, muscle strength, health profile, and quality of life in the early posttreatment (3rd week) stage and at the 3rd-month follow-up. When both groups were compared, a significant difference was determined between the VAS-Rest, VAS-Movement, PRUNES-Pain, PRUNES-Function, and PRUNES-Total parameters in the posttreatment (3rd week follow-ups), as well as PRUNES-Pain scores in the post-treatment (3rd month) stage, of the groups in favor of those in Group 1 (p < 0.05). Conclusion: The findings of our study have shown that in the treatment of CuTS, laser treatment is superior to placebo in the short term, but they have equivalent effects in the medium term. Further studies with large patient populations are needed to provide more diverse information about the therapeutic effectiveness of low-intensity laser therapy.

Sensitivity and specificity of the sensory collapse test for nerve entrapment syndrome in the upper extremity

OBJECTIVES

Several prospective blinded studies have found poorer sensitivity for the sensory collapse test than reported by Susan E Mackinnon's team. However, the blinded examiner had no knowledge of the patient's clinical presentation, or even of the purpose of the test. In these conditions, it seems difficult to perform the sensory collapse test correctly. The aim of the present study was to evaluate the efficacy of the sensory collapse test in the diagnosis of nerve compression in the upper extremity, using a trained, "partially" blinded examiner, with a minimum of clinical information in order to avoid bias due to poor execution of the test, while still unable to influence the test result.

METHODS

Seventy-two patients with diagnosis of nerve entrapment in the upper extremity were included prospectively. The sensory collapse test was performed by two examiners, one of whom was blinded to laterality and to the site of nerve compression, aware only of the affected nerve. Using electrodiagnosis study as reference, the sensitivity and specificity of the sensory collapse test were calculated for each examiner.

RESULTS

The unblinded examiner showed 72% sensitivity and 57% specificity, and the blinded 68% sensitivity and 57% specificity.

CONCLUSIONS

The sensory collapse test is useful for diagnosis of nerve entrapment in the upper limb, even with a blinded examiner.

LEVEL OF EVIDENCE: 3

Optimizing Outcomes in Revision Peripheral Nerve Surgery of the Upper Extremity

Peripheral nerve surgeries for compressive neuropathy in the upper extremity are generally successful. However, cases that either fail or have complications requiring revision surgery are challenging. During revision consideration, surgeons should perform a comprehensive preoperative workup to understand the etiology of the patient's symptoms and categorize symptoms as persistent, recurrent, or new in relation to the index procedure. Revision surgery often requires an open, extensile approach with additional procedures to optimize outcomes. Even with proper workup and treatment, clinical outcomes of revision surgeries are inferior compared to primary surgeries and patients should be well informed prior to undergoing such procedures.

Revision surgery for recurrent ulnar nerve compression following failed subcutaneous transposition

BACKGROUND

Recurrent ulnar nerve compression after primary anterior subcutaneous transposition is relatively rare, and revision surgery is challenging. This study retrospectively evaluated the clinical outcomes of revision anterior subcutaneous transposition for recurrent ulnar nerve compression.

METHODS

Eight patients who underwent revision anterior subcutaneous transposition for recurrent ulnar nerve compression were enrolled in this study. The outcomes were based on preoperative and postoperative symptoms, physical examination findings, and electromyographic evaluation.

RESULTS

Ulnar nerve enlargement was preoperatively found in all patients with a mean cross sectional area of 0.15 cm2 (range, 0.14-0.18 cm2). Intraoperative findings showed that recurrent compression occurred in three areas, including the medial intermuscular septum (n = 5), the medial epicondyle (n = 6) and nerve entrance to forearm fascia (n = 1). Post-operation, significant improvements were observed in ring/little finger numbness (from severe to mild, p = 0.031), grip strength (from 48.00% to 80.38% of the intact side, p < 0.001) and McGowan grade (from Grade III to Grade I, p = 0.049). Postoperative electromyography test also showed significant improvement in motor nerve conduction at elbow (velocity, 23.30 ± 9.598 vs. 35.30 ± 9.367, p = 0.012; amplitude, 3.40 ± 3.703 vs. 5.65 ± 2.056, p = 0.007) and sensory nerve conduction at wrist (velocity, 27.04 ± 22.450 vs. 36.45 ± 18.099, p = 0.139; amplitude, 1.44 ± 1.600 vs. 4.00 ± 2.642, p = 0.011). Seven of the eight patients reported satisfaction with the postoperative results.

CONCLUSIONS

Revision anterior subcutaneous transposition was an effective treatment for recurrent ulnar nerve compression from prior failed procedures.

A systematic review of steroid use in peripheral nerve pathologies and treatment

Background

The use of corticosteroids has become a part of the standard of care in various pathologies but their use in peripheral nerve injury treatment is limited. Given corticosteroids' anti-inflammatory properties and their regulatory role in neuronal protein production and myelination, corticosteroids could serve as an adjunct therapy for peripheral nerve injuries. This review aims to systematically investigate the current use of corticosteroid treatment in peripheral nerve pathologies.

Methods

The systematic search was performed on PubMed, MEDLINE, EMBASE, Scopus, Cochrane, and Web of Science using keywords such as "corticosteroid treatment," "peripheral nerve damage," "peripheral neuropathy," and "complications." The PRISMA guidelines were used to conduct the systematic review and all articles were reviewed by the corresponding author. After the initial search, individual study titles and abstracts were further screened and categorized using an inclusion and exclusion criteria followed by a final full-text review.

Results

Out of the total 27,922 identified records, 203 studies were included based on the selection criteria. These studies focused on the use and efficacy of steroids across a spectrum of compression and non-compression peripheral neuropathies such as cubital tunnel syndrome and chronic inflammatory demyelinating polyradiculoneuropathy. Various studies noted the promising role of steroids in offering pain relief, nerve block, and nerve regeneration effects. Additionally, safety considerations and potential complications regarding steroid use in peripheral nerve injuries were analyzed.

Conclusion

While there is currently limited clinical utilization of corticosteroids in peripheral nerve pathologies, the anti-inflammatory and regenerative effects that steroids provide may be a beneficial tool in managing various peripheral neuropathies and their associated pain. Additional clinical trials and investigation into the mechanism of action could improve the reputation of steroid use as peripheral nerve injury treatment.

Postoperative Pathologies of the Hand Following Shoulder Surgery

Purpose

Shoulder arthroscopy and arthroplasty are increasingly common procedures used to address shoulder pathologies. This study sought to evaluate the incidence of hand-related pathologies, including carpal tunnel syndrome (CTS), cubital tunnel syndrome (CuTS), trigger finger (TF), de Quervain tenosynovitis, and Dupuytren disease following shoulder arthroscopy and arthroplasty procedures. We hypothesized that patients undergoing shoulder surgery would have a higher incidence of hand-related pathologies within 1 year of surgery compared to controls.

Methods

This was a retrospective analysis of 12,179 patients who underwent shoulder arthroscopy or arthroplasty surgery that were subsequently diagnosed with CTS, CuTS, TF, de Quervain tenosynovitis, or Dupuytren disease within 1 year after surgery. Relative risk of having associated hand pathologies following shoulder surgery was compared to controls.

Results

In total, 10,285 patients underwent shoulder arthroscopy procedures during this period, of whom 815 (7.9%) had an associated hand pathology within 1 year from their shoulder procedure. Arthroscopic surgery was associated with an increased likelihood of having a hand pathology (RR 1.65, 95% CI 1.54-1.76), CTS (RR 1.57, 95% CI 1.42-1.73), CuTS (RR 2.25, 95% CI 1.94-2.61), TF (RR 1.76, 95% CI 1.53-2.03), and Dupuytren disease (RR 2.02, 95% CI 1.54-2.65), but was not associated with a higher likelihood of having de Quervain tenosynovitis. In total, 1,894 patients underwent shoulder arthroplasty procedures during this period, of whom 188 (9.9%) had an associated hand pathology within 1 year. Shoulder arthroplasty was associated with an increased likelihood of having a hand pathology (RR 2.04, 95% CI 1.78-2.34), CTS (RR 2.10, 95% CI 1.72-2.57), CuTS (RR 3.29, 95% CI 2.48-4.39), and TF (RR 1.99, 95% CI 1.47-2.70), but was not associated with an increased likelihood of having de Quervain tenosynovitis or Dupuytren disease.

Conclusions

Shoulder arthroscopy and arthroplasty procedures were associated with an increased likelihood of having a CTS, CuTS, or a TF diagnosis made within 1 year of surgery. Only shoulder arthroscopy procedures were associated with a higher likelihood of having Dupuytren disease. Neither shoulder arthroscopy nor arthroplasty procedures were associated with an increased likelihood of a diagnosis of de Quervain tenosynovitis. These associations, however, do not necessarily imply causation, and further investigation is warranted to delineate this relationship.

Type of study/level of evidence

Differential Diagnosis/Symptom Prevalence Study Level 3.

Novel Technique for Ulnar Nerve Transposition at the Elbow: The Neocubital Tunnel

Background

Many standard surgical procedures for cubital tunnel syndrome rely on ulnar nerve transposition at the elbow. Placing the ulnar nerve anterior to the axis of motion decreases compression during flexion. Subcutaneous, subfascial, and submuscular positioning of the ulnar nerve may predispose to nerve irritation, instability, and compression in the two first scenarios, and requires invasive dissection in the third one. With no single procedure demonstrating clear advantages and outcomes, this study reports the results of a novel technique using the epitrochleo-olecranon ligament to create a neo-tunnel, anatomically stabilizing the ulnar nerve.

Methods

Nine consecutive patients were enrolled. Patients were evaluated qualitatively for symptomatic improvements using physical examination. The Wilson and Krout, modified McGowan, and PRUNE grading scores were used for quantitative measurement.

Results

Postoperatively, all patients reported subjective improvement in symptoms and functional improvement. There were no intraoperative or postoperative complications. Baseline severity of disease was evaluated using the McGowan scale (modified by Goldberg): eight (89%) grade IIA patients and one (11%) grade III patient. Postoperatively, seven (78%) patients were reduced to grade 0, and two (22%) patients to grade 1 (P < 0.001). Using the Wilson and Krout criteria, outcomes were as follows: six (67%) excellent, two (22%) good, and one (11%) fair. The mean postoperative PRUNE survey score was 19.3 (SD ± 24.4).

Conclusions

The neocubital tunnel technique is a relatively noninvasive, safe surgical alternative that may be considered when an anterior transposition of the ulnar nerve is indicated for surgical decompression of the cubital tunnel.

Higher Revision Rates With In Situ Decompression as Compared to Ulnar Nerve Transposition for Cubital Tunnel Syndrome: A Meta-Regression Analysis

The purpose of this study was to examine the effect of follow-up time on revision rates of in situ decompression and ulnar nerve transposition for the surgical treatment of cubital tunnel syndrome. A comprehensive literature search was performed to identify prospective and retrospective primary comparison studies assessing the revision rates of in situ decompression and ulnar nerve transposition for the treatment of cubital tunnel syndrome. Meta-regression analyses were used to assess the effect of average study follow-up on the revision rates of both cubital tunnel syndrome treatments. Modeling results were then used to estimate revision rates between decompression and transposition at increasing follow-up times. Sixteen studies including 2,225 patients were included. Average study follow-up time was a statistically significant moderator of revision rates. Model predictions show that in situ decompression operations had an increased risk for revision as compared to ulnar transposition after 48 months of follow-up. In studies with follow-up time ≥48 months, revision rates for in situ decompression (11.9%) were significantly greater than in ulnar transposition (3.2%). In situ decompression for cubital tunnel syndrome is associated with an increased risk of revision surgery as compared to ulnar nerve transposition, particularly when assessed at longer follow-up intervals. The effect of follow-up duration on revision rates demonstrates the need for additional studies to compare outcomes of these operative approaches at follow-up times ≥48 months. This study provides evidence that ulnar nerve transposition may ultimately lead to lower revision rates and demonstrates the need for prospective, randomized trials to corroborate this effect.

A novel classification of intraoperative ulnar nerve instability to aid transposition surgery

HYPOTHESIS

The purpose of this study was to compare inter- and intraobserver agreement of a novel intraoperative subluxation classification for patients undergoing ulnar nerve surgery at the elbow. We hypothesize there will be strong inter- and intraobserver agreement of the 4-category classification system, and reviewers will have substantial confidence while reviewing the classification system.

METHODS

Four blinded fellowship-trained orthopedic hand surgeons reviewed 25 videos in total on 2 separate viewings, 21 days apart. Variables collected were ulnar subluxation classification (A, B, C, or D) and a confidence metric. Subsequent to primary data collection, classification grading was stratified into A/B or C/D subgroups for further analysis. Cohen κ scores were used to evaluate all variables collected in this study. The interpretation of κ scores included ≤0.0 as no agreement, 0.01-0.20 as none to slight, 0.21-0.40 as fair, 0.41-0.60 as moderate, 0.61-0.80 as substantial, and 0.81-1.0 as almost perfect agreement.

RESULTS

Interobserver agreement of subluxation classification as a 4-category scale demonstrated a moderate agreement on first viewing, second viewing, and when both viewings were combined (κ = 0.51, 0.51, and 0.51 respectively). Seventy-five percent (3 of 4) of reviewers had moderate intraobserver agreement for ulnar nerve subluxation classification, whereas 1 reviewer had substantial intraobserver classification (κ = 0.72). Overall, there was high confidence in 65% of classification scores in the second round of viewing, which improved from 58% in the first viewing round. When ulnar subluxation classification selections were regrouped into classes A/B or C/D, 100% of reviewers had substantial interobserver (κ = 0.74-0.75) and substantial to almost perfect intraobserver (κ = 0.71-0.91) agreement.

CONCLUSIONS

The 4-category classification was reproducible within and between reviewers. Agreement appeared to increase when simplifying the classification to 2 categories, which may provide guidance to surgical decision making. The validation of a reproducible classification scheme for intraoperative ulnar subluxation may aid with decision making and further postoperative outcomes research.

Presurgical management of ulnar nerve entrapment in patients with and without diabetes mellitus

Diabetes mellitus (DM) is a risk factor for the development of ulnar nerve entrapment (UNE). Differences in surgical outcomes for UNE between patients with and without DM have been reported, but studies on presurgical management are scarce. This study aimed to evaluate the presurgical management of UNE in patients with (DM diagnosis < 2 years of UNE diagnosis) and without DM regarding the level of care for diagnosis and the proportion that proceeds to surgery. Data from 6600 patients with UNE between 2004 and 2019 were included from the Skåne Health Care Register (SHR) and cross-linked with data from the Swedish National Diabetes Register (NDR). The group with UNE and DM was compared to the group with UNE without DM and prevalence ratios were calculated using Cox regression analysis. Patients with DM more often got their first UNE diagnosis in secondary care than in primary care (643/667, 96% vs. 5361/5786; 93%). Patients with and without DM, regardless of the type of DM, presence of retinopathy, or HbA1c levels, were surgically treated for UNE to the same extent (258/667, 39% of patients with DM vs. 2131/5786, 37% of patients without DM). The proportion of surgically treated was significantly lower among patients diagnosed with UNE in primary care compared to secondary care (59/449, 13% vs. 2330/5786, 38%). Men were more often surgically treated than women (1228/3191, 38% vs.1161/3262 36%). Patients with UNE and DM are surgically treated to the same extent as patients with UNE but without DM and are more likely to be diagnosed in specialized care.

Return to Activity Following Isolated Ulnar Nerve Surgery: A Systematic Review

Ulnar neuropathy is one of the more commonly diagnosed mononeuropathies; despite this, a definitive surgical treatment strategy has not been widely agreed upon. In this study, we systematically review the literature and assess return to play or activity outcomes in patients with neuritis or neuropathy undergoing in situ decompression, subcutaneous transposition, or submuscular transposition of the ulnar nerve. We hypothesized that ulnar nerve transposition or decompression in the absence of concomitant ulnar collateral ligament (UCL) pathology would have a high rate of return to activity. Relevant studies were generated from 1975 to 2023 using PubMed, Academic Search Complete, CINAHL (Cumulative Index to Nursing and Allied Health Literature), MEDLINE, and SPORTDiscus. Articles reporting on return to play or activity outcomes following isolated ulnar nerve transposition or decompression for ulnar neuritis were included. Studies evaluating patients with concomitant UCL injury or revision surgery were excluded. A total of 12 studies met the inclusion criteria, ranging from 1977 to 2021. There were a total of 358 patients with a reported return to play or activity status across all studies with an average age of 27.2 years (range, 11-75). Successful return to play, activity, or work was reported in 303 patients (84.6%). Patients undergoing transposition, subcutaneous (n = 232) and submuscular (n = 20), had return rates of 87.9% and 95%, respectively. Patients undergoing in situ decompression (n = 106) had return rates of 75.5%. This systematic review found an 84.6% return to activity rate following ulnar nerve transposition or decompression in the absence of concomitant UCL pathology. Overall, transposition or decompression of the ulnar nerve provides a favorable return to activity rates and with appropriate indications and surgical technique will likely yield a successful return.

Ultrasound Measurements of the Ulnar Nerve at the Medial Epicondyle Correlate With Electrodiagnostic Studies

BACKGROUND

Cubital tunnel syndrome is the second most common compressive neuropathy in the upper extremity and is commonly evaluated with electrodiagnostic studies (EDS). Ultrasound (US) has emerged as a potentially more efficient alternative to EDS. The purpose of this study is to evaluate whether measurements of the cross-sectional area (CSA) of the ulnar nerve at the elbow correlate with EDS results.

METHODS

This study was a prospective analysis of patients who presented with signs and symptoms consistent of cubital tunnel syndrome, who received USs of the ulnar nerve at the elbow and nerve conduction tests. Pearson correlation coefficients were used to evaluate the correlation between ulnar nerve CSA and electrodiagnostic data. t Tests were used to evaluate statistical differences between the mean ulnar nerve CSA of patients with positive or negative nerve conduction study results. Youden Index was used to calculate the optimal cut-off point for US CSA based on maximal sensitivity and specificity. Statistical significance was based on a two-sided P less than .05.

RESULTS

The association between increasing US CSA at the medial epicondyle with slowing of the conduction velocity of the ulnar motor nerve across the elbow was statistically significant (r = -0.35, P = .02). Patients with positive EDS tests had significantly larger nerve size than those with negative tests (all Ps < .03). A cut-off point of greater than or equal to 11 mm2 had a sensitivity of 70.83% and specificity of 66.67%.

CONCLUSIONS

Larger ulnar nerve CSAs correlate with slowing of the conduction velocity on EDSs, and those with positive EDSs have larger nerve sizes than those with negative tests.

The Use of Physiotherapy in the Conservative Treatment of Cubital Tunnel Syndrome: A Critical Review of the Literature

BACKGROUND

The lack of a clear answer regarding the efficacy of physiotherapy in the treatment of cubital tunnel syndrome (CuTS) has led to attempts to critically assess the scientific studies conducted to date.

MATERIALS AND METHODS

Two databases (MEDLINE via PubMed and PEDro) and Google Scholar were used to search for papers. The inclusion criteria were randomized controlled trials, case series, and case reports that evaluate the effects of physiotherapy in the treatment of patients with CuTS.

RESULTS

A total of 18 studies met the eligibility criteria, capturing a total of 425 participants. Seven papers were randomized controlled trials, three more described prospective studies without a control group, and eight papers contained case reports. An analysis of the literature evaluating the effectiveness of various forms of broadly defined physiotherapy indicates that their use can have a beneficial effect in reducing many subjective and objective symptoms and improving function. In the majority of papers included in this review, their authors indicated positive therapeutic effects. Only one randomized controlled trial reported no change following therapy. It can therefore be stated that the results of the research conducted so far are optimistic. However, only 7 of the 18 papers were randomized controlled trials, while 3 were prospective studies, and 8 papers were case studies, in which 23 people with CuTS were studied.

CONCLUSIONS

The small number of randomized clinical trials and their considerable heterogeneity do not allow firm conclusions to be drawn about the effectiveness of physiotherapy in the conservative treatment of CuTS.

Gray-Scale and Power Doppler Ultrasound Findings Predictive of Cubital Tunnel Syndrome Severity

BACKGROUND

The use of ultrasound in the diagnosis of cubital tunnel syndrome (CuTS) is an attractive alternative to electrodiagnostic (EDX) studies, but its utility is binary with poor severity correlation. We hypothesize that increasing ulnar nerve cross-sectional area (CSA) and power Doppler measurement of intraneural vascularity may predict the extent of disease.

METHODS

We identified 20 elbows from patients with a history of CuTS and 20 elbows in 10 asymptomatic controls. Electrodiagnosis was performed for symptomatic patients. Gray-scale ultrasound and power Doppler ultrasound were performed to measure CSA and intraneural vascularity in all participants. Functional measures, Boston Carpal Tunnel Questionnaire (BCTQ), and Patient-Reported Outcomes Measurement Information System surveys were also completed.

RESULTS

A strong positive correlation was found between CSA and motor nerve conduction velocity (MNCV) decrease between elbow and forearm, which increased when BCTQ >2 was used as a screening criterion. Increased CSA also demonstrated a high positive predictive value (PPV) in predicting MNCV changes, but poor ability to predict axonal loss. In contrast, power Doppler ultrasound demonstrated 100% PPV and 94% negative predictive value (NPV) in predicting severe CuTS (defined as compound motor action potential [CMAP] amplitude <6 mV and electromyography [EMG] findings).

CONCLUSIONS

Cross-sectional area is a sensitive method for identifying changes in MNCV and amplitude but does not stratify disease severity, as defined by diminished CMAP amplitude and/or evidence of denervation on EMG. The presence of increased intraneural vascularity is relatively sensitive but highly specific for axonal loss. The combination of nerve CSA, BCTQ screening, and power Doppler ultrasound may provide an alternative means for CuTS assessment.

Volumetric assessment of ulnar nerves in cubital tunnel syndrome with 3D modeling of the MRI and its relationship with electrodiagnostic findings

BACKGROUND

Thickened nerve cross-sectional areas (CSA) have been investigated in compressive neuropathy, but the longitudinal extent of nerve swelling has yet to be evaluated. We did a volumetric assessment of the ulnar nerve in cubital tunnel syndrome (CuTS) with three-dimensional (3D) magnetic resonance imaging (MRI) modeling and investigated this relationship with clinical and electrodiagnostic parameters.

METHODS

We compared 40 CuTS patient elbow MRIs to 46 patient elbow MRIs with lateral elbow epicondylitis as controls. The ulnar nerve was modeled with Mimics software and was assessed qualitatively and quantitatively. The CSA and ulnar nerve volumes were recorded, and the area under the receiver operating characteristic (ROC) curve was calculated for diagnostic performance. We analyzed clinical and electrodiagnostic parameters to investigate their relationship with the 3D ulnar nerve parameters.

RESULTS

For the diagnosis of CuTS, the area under the curve value was 0.915 for the largest CSA and 0.910 for the volume in the ROC curve. The optimal cut-off was 14.53 mm2 and 529 mm3 respectively. When electrodiagnostic parameters were investigated, the 3D ulnar nerve volume was significantly inversely associated with motor conduction velocity, although there was no association between the largest CSA and any of the electrodiagnostic parameters.

CONCLUSIONS

The 3D ulnar nerve volume, which is an integration or multilevel measurement of CSAs, showed diagnostic usefulness similar to CSA, but it correlated better with conduction velocity, indicating demyelination or early-to-moderate nerve damage in CuTS.

Utilizing Diagnostic Musculoskeletal Ultrasound in the Evaluation of Cubital Tunnel Syndrome and Ulnar Nerve Pathology

Cubital Tunnel Syndrome (CTS), is a frequently encountered condition in clinical settings, typically arising from static or dynamic compression of the ulnar nerve. CTS is characterized by the irritation of the ulnar nerve within the cubital tunnel and is a common neuropathic condition that can significantly impact functional abilities and quality of life. This article explores the utility of diagnostic musculoskeletal ultrasound (MSK-US) in the evaluation of the cubital tunnel and the ulnar nerve. The cubital tunnel syndrome, a common entrapment neuropathy of the ulnar nerve, often presents diagnostic challenges. Traditionally, nerve conduction studies and electromyography have been the primary diagnostic tools used to diagnose CTS. Given the superficial nature of the ulnar groove and its adjacent structures, MSK-US imaging known for its non-invasive nature and high-resolution imaging capabilities, has become an increasingly valuable tool in the assessment and management of various musculoskeletal conditions. This article reviews the technical aspects of MSK-US, its advantages in visualizing the ulnar nerve and related structures, and its implications in clinical practice for rehabilitation providers. By integrating MSK-US in the evaluation of CTS, rehabilitation professionals can enhance diagnostic accuracy, tailor interventions, and improve patient outcomes.

Cubital tunnel syndrome associated with previous ganglion cyst excision in the elbow: a case report

Cubital tunnel syndrome refers to compression neuropathy caused by pressure on the ulnar nerve pathway around the elbow. A 63-year-old male patient visited the clinic complaining of decreased sensation and weakness in his left ring finger and little finger, stating that the symptoms first began 6 months prior. He had undergone surgery to remove a ganglion cyst from his left elbow joint about 5 years prior in Mongolia. Magnetic resonance imaging revealed a cystic mass located at the previous surgical site, which was compressing the ulnar nerve within the cubital tunnel. Ulnar nerve decompression and anterior transposition were performed, and the cystic mass was excised. Upon pathological examination, the mass was diagnosed as a ganglion cyst. The patient's symptoms including sensory dysfunction and weakness improved over the 1-year follow-up period. This report describes a rare case of ganglion cyst recurrence compressing the ulnar nerve in the cubital tunnel after previous ganglion cyst excision.

Anterior transposition and positioning via helix sling method in cubital tunnel syndrome: An open-label, retrospective trial of maximum 5-year follow-up

Background

Ulnar nerve transposition is used for cubital tunnel syndrome (CuTS) with nerve instability. The aim is to report a modified technique for ulnar nerve transposition using medial intermuscular septum and Osborne's ligament as a double-strand helix sling to recreate a sliding channel for the ulnar nerve and the functional outcomes at follow-ups.

Methods

Twenty-five patients with persistent CuTS underwent nerve release and subcutaneous transposition from January 2017 to January 2022 in our institute. Among them, 9 patients were excluded due to incomplete medical records, lack of follow-up history, or bilateral limb numbness. The medial intermuscular septum with one end attached was excised to rebuild a tension-free double-strand helix sling by anchoring at the residue of Osborne's ligament. The modified Mc-Gowan classification was applied to evaluate the disease severity preoperatively. The quick disability of arm and shoulder and hand (quickDASH) questionnaire and visual analogue scale (VAS) scores were used to evaluate pre- and postoperative symptoms. Ultrasound imaging was utilized for nerve structure evaluation before surgery and at follow-ups.

Results

Sixteen out of twenty-five patients received follow-ups postoperatively (ranging from 9 to 69 months, 36 months in average). No findings indicated subluxation of ulnar nerve or recompression by ultrasound imaging examination. According to quickDASH and VAS scores and physical examination, 14 out of 16 patients showed postoperative improvement in symptoms and function at final follow-ups.

Interpretation

In this modified technique, the medial intermuscular septum and Osborne's ligament can create tension-free helix sling for stable and smooth sliding and preventing subluxation after nerve transposition, which is highly effective and safe for CuTS treatment.

Diagnosis of Ulnar Neuropathy at the Elbow Using Ultrasound - A Comparison to Electrophysiologic Studies

PURPOSE

Given the relatively high false negative rate of electrodiagnostic studies (EDX) in patients with clinically diagnosed ulnar neuropathy at the elbow (UNE), we sought to determine whether an alternative objective test could more effectively detect UNE. Additionally, we proposed to determine the relationship between the cross-sectional area (CSA) of the ulnar nerve on ultrasound (US), EDX, and clinical symptoms.

METHODS

This was a retrospective study of patients presenting with symptomatic UNE. The performance characteristics of EDX versus ultrasound were calculated using the clinical diagnosis of UNE as the reference standard. Standard EDX studies and US of the ulnar nerve were analyzed. Maximal CSA of the ulnar nerve and EDX severity were analyzed for patients with each combination of US-positive/negative and EDX-positive/negative findings.

RESULTS

Analysis was performed on 89 patients and 115 nerves with signs and symptoms of cubital tunnel syndrome. In total, 56 (49%) nerves were diagnosed as mild UNE, 32 (28%) nerves were diagnosed as moderate UNE, 17 (15%) nerves were diagnosed as severe UNE, and 10 (8%) nerves were negative for UNE by EDX. Maximal-maximal CSA was highly correlated with disease severity as determined by nerve conduction studies/electromyography. Compared with EDX+/US+, patients with EDX-/US+ showed higher rates of ulnar sensory loss and elbow tenderness with similar rates of positive Tinel and intrinsic muscle atrophy. In this sample of patients with clinically diagnosed UNE, 91.3% of the patients demonstrated positive EDX studies, whereas 94.8% had a positive US.

CONCLUSIONS

Ultrasound is an alternative to EDX that could be incorporated clinically in the diagnosis and management of UNE. Ultrasound was able to consistently detect clinically positive cubital tunnel syndrome demonstrating its utility as a confirmatory or supplemental test to the clinical assessment if one is required. Ultrasound additionally may be able to better identify patients with early stages of UNE with negative EDX findings.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

Do Socioeconomic Factors Affect Symptom Duration and Disease Severity at Presentation for Cubital Tunnel Syndrome?

BACKGROUND

Socioeconomic factors have been implicated in delayed presentation for compressive neuropathies of the upper extremity. Our article seeks to elucidate the effect of socioeconomic factors on self-reported symptom duration and objective disease severity at presentation for cubital tunnel syndrome.

METHODS

This retrospective cohort study included 207 patients with surgical management of cubital tunnel syndrome at 2 institutions between June 1, 2015, and March 1, 2020. Exclusion criteria included age under 18 years, revision surgery, lack of preoperative electrodiagnostic studies, and concurrent additional surgeries. Response variables were self-reported symptom duration, time from presentation to surgery, McGowan grade, and electrodiagnostic measures. Explanatory variables included age, sex, white race, diabetes mellitus, depression, anxiety, and the Distressed Communities Index.

RESULTS

Symptom duration was associated with nonwhite race, and time from presentation to surgery was associated with insurance provider. More clinically severe disease was associated with older age, male sex, and not having carpal tunnel syndrome. Nonrecordable sensory nerve action potential latency was associated with older age, higher body mass index, male sex, diabetes mellitus, and unemployment. Nonrecordable conduction velocities were associated with older age, and having fibrillations at presentation was associated with older age, male sex, and unemployment.

CONCLUSIONS

Economic distress is not associated with self-reported symptom duration, time from presentation to surgery, or presenting severity of cubital tunnel syndrome. White patients presented with shorter self-reported symptom duration. Insurance type was associated with delay from presentation to surgery. Older age and male sex were risk factors for more clinically severe disease at presentation.

Role of high-resolution ultrasound and magnetic resonance neurography in the evaluation of peripheral nerves in the upper extremity

Upper extremity entrapment neuropathies are common conditions in which peripheral nerves are prone to injury at specific anatomical locations, particularly superficial regions or within fibro-osseous tunnels, resulting in pain and potential disability. Although neuropathy is primarily diagnosed clinically by physical examination and electrophysiology, imaging evaluation with ultrasound and magnetic resonance neurography are valuable complementary non-invasive and accurate tools for evaluation and can help define the site and cause of nerve dysfunction which ultimately leads to precise and timely treatment. Ultrasound, which has higher spatial resolution, can quickly and comfortably characterize the peripheral nerves in real time and can evaluate for denervation related muscle atrophy. Magnetic resonance imaging on the other hand provides excellent contrast resolution between the nerves and adjacent tissues, also between pathologic and normal segments of peripheral nerves. It can also assess the degree of muscle denervation and atrophy. As a prerequisite for nerve imaging, radiologists and sonographers should have a thorough knowledge of anatomy of the peripheral nerves and their superficial and deep branches, including variant anatomy, and the motor and sensory territories innervated by each nerve. The purpose of this illustrative article is to review the common neuropathy and nerve entrapment syndromes in the upper extremities focusing on ultrasound and magnetic resonance neurography imaging.

Where Does Ultrasound Fit in the Diagnostic Algorithm for Cubital Tunnel Syndrome?

BACKGROUND

Ultrasound (US) has emerged as a promising supplement to electrodiagnostic studies (EDX) in the diagnosis of cubital tunnel syndrome (CuTS) and has potential to be performed by novice operators. Our objective is to understand the discrepancies in assessment between the two modalities and to assess the utility of US in CuTS diagnosis by a novice operator.

METHODS

Patients who presented to a single tertiary academic medical center and clinically diagnosed with CuTS were prospectively enrolled. Electrodiagnostic studies were performed along with US measurements of the cross-sectional area (CSA) of the ulnar nerve by both a board-certified physiatrist and novice operator. Electrodiagnostic study and US outcomes were compared among four diagnostic impression groups: EDX-/US-, EDX+/US-, EDX-/US+, and EDX+/US+.

RESULTS

Sixteen patients were classified as abnormal by both EDX and US, 14 were classified abnormal by US only, 3 were classified abnormal by EDX only, and 6 were classified normal by both EDX and US (P = .008, K = 0.14). The EDX+/US+ group had a significantly reduced sensory amplitude compared with the EDX-/US+ (P = .04) group. Diagnostic classifications between a board-certified physiatrist and novice operator were in moderate agreement (K = 0.58, P = .08).

CONCLUSIONS

Ultrasound detected a greater proportion of patients as abnormal than EDX. A subset of patients with clinical diagnoses of CuTS had normal sensory amplitudes but increased maximum nerve CSAs. Competency in US may be easily acquired with minimal training, suggesting its potential to be extended for use by other members of the health care team.

Olympic Elbow Comprising Lateral Epicondylitis, Cubital Tunnel Syndrome, and Distal Biceps Tendon Rupture

There is a wide range of elbow injuries including chronic injuries such as lateral epicondylitis, medial epicondylitis, and cubital tunnel syndrome, or acute injuries such as elbow fracture-dislocations and distal biceps tendon ruptures. Combinations of acute and chronic elbow injuries have been reported including country club elbow and terrible triad of the elbow which are important to identify to properly treat. Thus, we report for the first time a new elbow injury triad termed Olympic elbow in a 65-year-old man comprising lateral epicondylitis, cubital tunnel syndrome, and a distal biceps tendon rupture. After initially failing conservative management, the patient was successfully treated with surgery and has returned to full physical activity at four and a half years postoperatively.

Cubital Tunnel Syndrome: Does a Consensus Exist for Diagnosis?

PURPOSE

Cubital tunnel syndrome (CuTS) is the second most common compressive neuropathy of the upper extremity. We aimed to determine a consensus among experts using the Delphi method for clinical criteria that could be validated further for the diagnosis of CuTS.

METHODS

The Delphi method was used for establishing a consensus among a group of expert panelists, comprising 12 hand and upper-extremity surgeons, who ranked the diagnostic clinical importance of 55 items related to CuTS on a scale from 1 (least important) to 10 (most important). The average and SDs of each item were calculated, and Cronbach α was used to assess homogeneity among the panelist-ranked items.

RESULTS

All panelists answered the 55-item questionnaire. A Cronbach α value of 0.963 was obtained on the first iteration. The top criteria that were considered most clinically relevant to the diagnosis of CuTS among the group were determined based on the most highly ranked and correlated items among the expert panelist group. The criteria based on which there was agreement were as follows: (1) paresthesias in ulnar nerve distribution, (2) symptoms precipitated by increased elbow flexion/positive elbow flexion tests, (3) positive Tinel sign at the medial elbow, (4) atrophy/weakness/ late findings (eg, claw hand of the ring/small finger and Wartenberg or Froment sign) of ulnar nerve-innervated muscles of the hand, (5) loss of two-point discrimination in ulnar nerve distribution, and (6) similar symptoms on the involved side after successful treatment on the contralateral side.

CONCLUSIONS

Our study demonstrated a consensus among an expert panelist group of hand and upper-extremity surgeons on potential diagnostic criteria for CuTS. This consensus on diagnostic criteria may help clinicians readily diagnose CuTS in a standardized form; however, further weighting and validation are necessary prior to the development of a formal diagnostic scale.

CLINICAL RELEVANCE

This study is the first step in producing a consensus on how to diagnose CuTS.

Safety of Cubital Tunnel Release Under General versus Regional Anesthesia

Purpose

The aim of this study was to evaluate the occurrence of early (<6 weeks) post-operative complications following ulnar nerve decompressions at the cubital tunnel performed under regional anesthesia compared to those performed under general anesthesia.

Methods

In situ ulnar nerve decompressions at the cubital tunnel performed at a single institution from 2012 through 2019 were retrospectively reviewed. Post-operative complications were compared between subjects who underwent the procedure with regional versus general anesthesia.

Results

Ninety-one ulnar nerve in situ decompressions were included in the study, which were performed under regional anesthesia in 55 and general anesthesia in 36 cases. The occurrence of post-operative complications was not significantly different between patients who received regional (n = 7) anesthesia and general (n = 8) anesthesia. None of the complications were directly attributed to the type of anesthesia administered. The change in pre- and post-operative McGowan scores were not significantly different between anesthesia groups (p = 0.81).

Conclusion

In situ ulnar nerve decompression at the cubital tunnel under regional anesthesia does not result in increased post-operative complications compared to those surgeries performed under general anesthesia. In situ ulnar nerve decompression performed under regional anesthesia is a safe and reliable option for patients who wish to avoid general anesthesia.

Level of Evidence

III.

Modern Treatment of Cubital Tunnel Syndrome: Evidence and Controversy

Cubital tunnel syndrome is the second most common peripheral mononeuropathy in the upper extremity. However, the diagnosis and treatment of cubital tunnel syndrome remains controversial without a standard algorithm. Although diagnosis can often be made from the patient's history and physical examination alone, electrodiagnostic studies, ultrasound, computed tomography (CT), and magnetic resonance image (MRI) can also be useful in diagnosing the disease and selecting the most appropriate treatment option. Treatment options include conservative nonoperative techniques as well as various surgical options, including in situ decompression with or without transposition, medial epicondylectomy, and nerve transfer in advanced disease. The purpose of this review is to summarize the most up-to-date literature regarding cubital tunnel syndrome and propose a treatment algorithm to provide clarity about the challenges of treating this complex patient population.

Endoscopic Release of the Ulnar Nerve at the Elbow: Technique Description and Case Series

Objective  The endoscopic release of the ulnar nerve reproduces a simple ( in situ ) procedure with smaller incisions, less soft tissue damage, and higher preservation of nerve vascularization. Endoscopy allows the clear visualization of the entire path of the nerve and surrounding noble structures. Moreover, it reveals any signs of compression and allows a safe release of 10 cm distally or proximally to the medial epicondyle. Methods  A retrospective survey revealed that 15 subjects (1 with a bilateral injury) underwent an ulnar nerve compression release at the elbow using the endoscopic technique with Agee (Micro-Aire Sugical Instruments, Charlottesville, VA, EUA) equipment from January 2016 to January 2020. Results  Symptoms of ulnar nerve compression improved in all patients; on average, they resumed their work activities in 26.5 days. There was no recurrence or need for another procedure. In addition, there were no severe procedure-related complications, such as infection and nerve or vascular injury. One patient had transient paresthesia of the sensory branches to the forearm, with complete functional recovery in 8 weeks. Conclusion  Our study shows that the endoscopic release of the ulnar nerve at the elbow with the Agee equipment is a safe, reliable technique with good outcomes.

Precision of Ultrasound-Guided versus Anatomical Palpation-Guided Needle Placement of the Ulnar Nerve at the Cubital Tunnel: A Cadaveric Study

Percutaneous electrical stimulation has been performed for years with only the assistance of anatomical landmarks. The development of real-time ultrasonography guidance has improved the precision and safety of these percutaneous interventions. Despite ultrasound-guided and palpation-guided procedures being performed routinely for targeting nerve tissues in the upper extremity, the precision and safety of these techniques are unknown. The aim of this cadaveric study was to determine and compare the precision and safety of ultrasound-guided versus palpation-guided needling procedure with and without the handpiece of the ulnar nerve on a cadaveric model. Five physical therapists performed a series of 20 needle insertion tasks each (n = 100), 10 palpation-guided (n = 50) and 10 ultrasound-guided (n = 50) on cryopreserved specimens. The purpose of the procedure was to place the needle in proximity to the ulnar nerve at the cubital tunnel. The distance to target, time performance, accurate rate, number of passes, and unintentional puncture of surrounding structures were compared. The ultrasound-guided procedure was associated with higher accuracy (66% vs. 96%), lower distance from needle to the target (0.48 ± 1.37 vs. 2.01 ± 2.41 mm), and a lower frequency of perineurium puncture (0% vs. 20%) when compared with the palpation-guided procedure. However, the ultrasound-guided procedure required more time (38.33 ± 23.19 vs. 24.57 ± 17.84 s) than the palpation-guided procedure (all, p < 0.001). Our results support the assumption that ultrasound guidance improves the accuracy of needling procedures on the ulnar nerve at the cubital tunnel when compared with palpation guidance.

Intraoperative electrical stimulation promotes the short-term recovery of patients with cubital tunnel syndrome after surgery

BACKGROUND

This study was designed to investigate whether intraoperative electrical nerve stimulation has effects on the short-term recovery of cubital tunnel syndrome patients after ulnar nerve release.

METHODS

Patients diagnosed as cubital tunnel syndrome were selected. At the same time, they received conventional surgery treatment. The patients were divided by a randomized digits table into two groups. The control group underwent conventional surgery, and the electrical stimulation (ES) group underwent intraoperative electrical stimulation. All the patients were tested for sensory and motor functions, grip strength, key pinch strength, motor conductivity velocity (MCV), and maximum compound muscle action potential (CMAP) before operation and 1 month and 6 months after operation.

RESULTS

In patients treated with intraoperative ES, the sensory and motor functions and the strength of muscle were significantly improved after 1-month and 6-month follow-up than the control group. After the follow-up, the patients in the ES group had significantly higher grip strength and key pinch strength than the control group. After the follow-up, the patients in the ES group had significantly higher MCV and CMAP than the control group.

CONCLUSION

Intraoperative electrical stimulation of nerve muscle can significantly promote the short-term recovery of nerve and muscle functions after the surgery in cubital tunnel syndrome patients.

Beyond the Cubital Tunnel: Use of Adjunctive Procedures in the Management of Cubital Tunnel Syndrome

BACKGROUND

Our management of cubital tunnel syndrome has expanded to involve multiple adjunctive procedures, including supercharged end-to-side anterior interosseous to ulnar nerve transfer, cross-palm nerve grafts from the median to ulnar nerve, and profundus tenodesis. We also perform intraoperative brief electrical stimulation in patients with severe disease. The aims of this study were to evaluate the impact of adjunctive procedures and electrical stimulation on patient outcomes.

METHODS

We performed a retrospective review of 136 patients with cubital tunnel syndrome who underwent operative management from 2013 to 2018. A total of 38 patients underwent adjunctive procedure(s), and 33 received electrical stimulation. A historical cohort of patients who underwent cubital tunnel surgery from 2009 to 2011 (n = 87) was used to evaluate the impact of adjunctive procedures. Study outcomes were postoperative improvements in Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire scores, pinch strength, and patient-reported pain and quality of life.

RESULTS

In propensity score-matched samples, patients who underwent adjunctive procedures had an 11.3-point greater improvement in DASH scores than their matched controls (P = .0342). In addition, patients who received electrical stimulation had significantly improved DASH scores relative to baseline (11.7-point improvement, P < .0001), whereas their control group did not. However, when compared between treatment arms, there were no significant differences for any study outcome.

CONCLUSIONS

Patients who underwent adjunctive procedures experienced greater improvement in postoperative DASH scores than their matched pairs. Additional studies are needed to evaluate the effects of brief electrical stimulation in compression neuropathy.

Recalcitrant Neuropathies in the Upper Extremity

Carpal and cubital tunnel syndrome can cause debilitating pain and weakness in the hand and upper extremities. Although most patients have a resolution of their symptoms after primary decompression, managing those with recalcitrant neuropathies is challenging. The etiology of persistent, recurrent, or new symptoms is not always clear and requires careful attention to the history and physical examination to confirm the diagnosis or consider other causes prior to committing to surgery. Nevertheless, revision surgery is often needed in the setting of recalcitrant neuropathies in order to improve patients' symptoms. Revision surgery typically entails wide exposure and neurolysis to release residual compression. In addition, vascularized tissue and nerve wraps have been routinely used to create a favorable perineural environment that decreases recurrent scar formation. This review discusses the etiologies of recalcitrant upper extremity neuropathies, the current treatment options, and surgical outcomes.

The Responsiveness of the Patient-Reported Outcomes Measurement Information System Upper Extremity and Physical Function in Patients With Cubital Tunnel Syndrome

PURPOSE

The Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity (UE) and PROMIS Physical Function (PF) are increasingly referenced patient-reported outcomes. To interpret treatment effects with these patient-reported outcomes, investigators must understand magnitudes of change that represent clinically relevant improvement. This study assessed the responsiveness of PROMIS UE and PF in patients with cubital tunnel syndrome.

METHODS

A retrospective analysis of PROMIS UE and PROMIS PF computer adaptive test scores was performed for patients treated nonoperatively for cubital tunnel syndrome over 3 years at a tertiary institution. The Patient-Reported Outcomes Measurement Information System UE and PROMIS PF outcome scores were collected at initial and return clinic visits. At follow-up appointments, patients completed clinical anchor questions evaluating their degree of interval clinical improvement. Anchor questions allowed categorization of patients into groups that had experienced "no change," "minimal change," and "much change." Minimal clinically important difference (MCID) values were calculated for the PROMIS assessments with anchor-based and distribution-based methods.

RESULTS

A total of 304 patients with PROMIS PF scores and 111 with PROMIS UE scores were analyzed. The MCID for the PROMIS UE was 3.1 (95% confidence interval, 1.4-4.8) using the anchor-based method and 3.7 (95% confidence interval, 2.9-4.4) using the distribution-based method. These point estimates exceeded the minimal detectable change of 2.3. The MCID for the PROMIS PF was unable to be determined in this patient sample because patients reporting mild change did not have score changes exceeding measurement error.

CONCLUSIONS

The PROMIS UE v2.0 computer adaptive test detected minimal change in patients managed nonoperatively for cubital tunnel syndrome with an estimated MCID range of 3.1-3.7. While PROMIS PF has demonstrated acceptable performance in patients with a variety of upper extremity conditions, for cubital tunnel syndrome, it was less able to detect subtle change. PROMIS UE appears more responsive to subtle changes in cubital tunnel syndrome symptoms.

CLINICAL RELEVANCE

Patient-reported outcomes may have varied responsiveness depending on the condition studied.

Does the Surgical Assistant Influence Perioperative Outcomes Surrounding Cubital Tunnel Surgery?

Background: Ulnar neuropathy at the elbow is the second most common upper extremity compressive neuropathy and surgical treatment often involves surgical trainee involvement. The primary aim of this study is to determine the effect of trainees and surgical assistants on outcomes surrounding cubital tunnel surgery. Methods: This retrospective study included 274 patients with cubital tunnel syndrome who underwent primary cubital tunnel surgery at two academic medical centres between 1 June 2015 and 1 March 2020. The patients were divided into four main cohorts based on primary surgical assistant: physician associates (PA, n = 38), orthopaedic or plastic surgery residents (n = 91), hand surgery fellows (n = 132), or both residents and fellows (n = 13). Exclusion criteria included patient age <18 years, revision surgery as the index procedure, prior traumatic ulnar nerve injury and concurrent procedures not related to cubital tunnel surgery. Demographics, clinical variables and perioperative findings were collected through chart reviews. Univariate and bivariate analyses were performed, and p < 0.05 was considered significant. Results: Patients in all cohorts had similar demographic and clinical characteristics. There was a significantly higher rate of subcutaneous transposition in the PA cohort (39.5% PA vs. 13.2% Resident vs. 19.7% Fellow vs. 15.4% Resident + Fellow). Presence of surgical assistants and trainees had no association with length of surgery, complications and reoperation rates. Although male sex and ulnar nerve transposition were associated with longer operative times, no explanatory variables were associated with complications or reoperation rates. Conclusions: Surgical trainee involvement in cubital tunnel surgery is safe and has no effect on operative time, complications or reoperation rates. Understanding the role of trainees and measuring the effect of graduated responsibility in surgery is important for medical training and safe patient care. Level of Evidence: Level III (Therapeutic).

Electrodiagnostic Predictors of Outcomes After In Situ Decompression of the Ulnar Nerve

PURPOSE

Patients with severe ulnar neuropathy at the elbow frequently experience suboptimal surgical outcomes. Clinical symptoms alone may not accurately represent the severity of underlying nerve injury, calling for objective assessment tools, such as electrodiagnostic studies. The goal of our study was to determine whether specific electrodiagnostic parameters can be used to predict the outcomes after in situ decompression of the ulnar nerve.

METHODS

This prospective study enrolled consecutive patients aged ≥18 years diagnosed with ulnar neuropathy at the elbow. Patients completed a baseline battery of motor, sensory, functional, and electrodiagnostic tests before undergoing in situ decompression of the ulnar nerve. They were reassessed at 6 weeks, 3 months, 6 months, and 12 months after surgery. Forty-two patients completed at least 2 follow-up assessments and were included in the study.

RESULTS

When controlling for other electrodiagnostic measurements and demographic factors, none of the electrodiagnostic parameters were predictive of outcomes at 12 months after surgery. Patients with decreased compound muscle action potential amplitudes demonstrated slower trends of recovery in grip strength, pinch strength, and overall scores on the Michigan Hand Outcomes Questionnaire as well as its function, work, and activities of daily living subscales, Disabilities of the Arm, Shoulder, and Hand questionnaire, and the Carpal Tunnel Questionnaire. Decreased motor nerve conduction velocity was predictive of slower recovery of 2-point discrimination and pinch strength.

CONCLUSIONS

Compound muscle action potential amplitude, but not other conventional electrodiagnostic parameters, was predictive of functional outcomes after in situ decompression of the ulnar nerve. This parameter should play a role in determining the timing and prognosis of treatment for ulnar neuropathy at the elbow.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

[Post-traumatic pain mononeuropathies]

Neuropathic pain syndrome (NPS) caused by peripheral nerve (PN) injury is a serious clinical problem due to its prevalence, complexity of pathogenesis, significant impact on the quality of life of patients. The issues of epidemiology, pathogenesis and treatment of patients with NBS with PN injury are considered. Modern possibilities of invasive treatment of such patients are discussed.

Dynamic Compression of the Ulnar Nerve Associated With the Anconeus Epitrochlearis Muscle: Do We Really Know Everything?

Ulnar nerve compression associated with the anconeus epitrochlearis muscle (AE) is an uncommon cause of peripheral nerve compression at the elbow. It is often seen in young women with a hypertrophied or severely edematous muscle. Its causes are unclear. Numerous observed features, such as a hypertrophic AE, a palpable mass on the medial side of the elbow, and the dynamic nature of symptoms, have sparked controversy in the literature. Its clinical presentation is often insidious, and occasionally symptoms only occur in prolonged positions (dynamic compression). EMG tests are usually negative, and a correct diagnosis relies on imaging. We present the case of a 21-year-old student and clarinet player who presented with dynamic compression of the ulnar nerve at the elbow associated with AE. Much remains to be elucidated about the incidence, pathophysiology, and contributing factors of this peripheral form of cubital compression. It may be time to revisit this condition.

A cadaveric study of ulnar nerve strain at the elbow associated with cubitus valgus/varus deformity

Background

Cubital tunnel syndrome can be caused by overtraction and dynamic compression in elbow deformities. The extent to which elbow deformities contribute to ulnar nerve strain is unknown. Here, we investigated ulnar nerve strain caused by cubitus valgus/varus deformity using fresh-frozen cadavers.

Methods

We used six fresh-frozen cadaver upper extremities. A strain gauge was placed on the ulnar nerve 2 cm proximal to the medial epicondyle of the humerus. For the elbow deformity model, osteotomy was performed at the distal humerus, and plate fixation was performed to create cubitus valgus/varus deformities (10°, 20°, and 30°). Ulnar nerve strain caused by elbow flexion (0–125°) was measured in both the normal and deformity models. The strains at different elbow flexion angles within each model were compared, and the strains at elbow extension and at maximum elbow flexion were compared between the normal model and each elbow deformity model. However, in the cubitus varus model, the ulnar nerve deflected more than the measurable range of the strain gauge; elbow flexion of 60° or more were considered effective values. Statistical analysis of the strain values was performed with Friedman test, followed by the Williams’ test (the Shirley‒Williams’ test for non-parametric analysis).

Results

In all models, ulnar nerve strain increased significantly from elbow extension to maximal flexion (control: 13.2%; cubitus valgus 10°: 13.6%; cubitus valgus 20°: 13.5%; cubitus valgus 30°: 12.2%; cubitus varus 10°: 8.3%; cubitus varus 20°: 8.2%; cubitus varus 30°: 6.3%, P < 0.001). The control and cubitus valgus models had similar values, but the cubitus varus models revealed that this deformity caused ulnar nerve relaxation.

Conclusions

Ulnar nerve strain significantly increased during elbow flexion. No significant increase in strain 2 cm proximal to the medial epicondyle was observed in the cubitus valgus model. Major changes may have been observed in the measurement behind the medial epicondyle. In the cubitus varus model, the ulnar nerve was relaxed during elbow extension, but this effect was reduced by elbow flexion.

Classifying the Severity of Cubital Tunnel Syndrome: A Preoperative Grading System Incorporating Electrodiagnostic Parameters

BACKGROUND

Current classifications for cubital tunnel syndrome have not been shown to reliably predict postoperative outcomes. In this article, the authors introduce a new classification that incorporates clinical and electrodiagnostic parameters, including compound muscle action potential amplitude, to classify the preoperative severity of cubital tunnel syndrome. The authors compare this to established classifications and evaluate its association with patient-rated improvement.

METHODS

The authors reviewed 44 patients who were treated surgically for cubital tunnel syndrome. Patients were retrospectively classified using their proposed classification and the Akahori, McGowan-Goldberg, Dellon, and Gu classifications. Correlation of grades was assessed by Spearman coefficients and agreement was assessed by weighted kappa coefficients. Patient-reported impairment was assessed using the Disabilities of the Arm, Shoulder, and Hand questionnaire before and after surgery.

RESULTS

The classifications tended to grade patients in a similar way, with Spearman coefficients of 0.60 to 0.85 ( p < 0.0001) and weighted kappa coefficients of 0.46 to 0.71 ( p < 0.0001). Preoperative Disabilities of the Arm, Shoulder, and Hand scores increased with severity grade for most classifications. In multivariable analysis, the authors' classification predicted postoperative Disabilities of the Arm, Shoulder, and Hand score improvement, whereas established classifications did not.

CONCLUSIONS

Established classifications are imperfect indicators of preoperative severity. The authors introduce a preoperative classification for cubital tunnel syndrome that incorporates electrodiagnostic findings in addition to classic signs and symptoms.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, III.

Cubital Tunnel Syndrome: Review of Diagnosis and Management

Cubital tunnel syndrome is one of the most common upper extremity nerve entrapment conditions. Clinical examination and electrodiagnostic studies assist in the diagnosis. Mild cases can be successfully treated conservatively, aiming to reduce traction and compression on the nerve. Surgical management of cubital tunnel syndrome is increasing in frequency. Multiple surgical options exist ranging from simple decompression to decompression and anterior transposition of the nerve. There is no preferred surgical technique. It is critical to reduce the risk of recurrent cubital tunnel syndrome. Revision surgical procedures have worse outcomes than primary surgical procedures.

Diagnosis of Cubital Tunnel Syndrome Using Deep Learning on Ultrasonographic Images

Although electromyography is the routine diagnostic method for cubital tunnel syndrome (CuTS), imaging diagnosis by measuring cross-sectional area (CSA) with ultrasonography (US) has also been attempted in recent years. In this study, deep learning (DL), an artificial intelligence (AI) method, was used on US images, and its diagnostic performance for detecting CuTS was investigated. Elbow images of 30 healthy volunteers and 30 patients diagnosed with CuTS were used. Three thousand US images were prepared per each group to visualize the short axis of the ulnar nerve. Transfer learning was performed on 5000 randomly selected training images using three pre-trained models, and the remaining images were used for testing. The model was evaluated by analyzing a confusion matrix and the area under the receiver operating characteristic curve. Occlusion sensitivity and locally interpretable model-agnostic explanations were used to visualize the features deemed important by the AI. The highest score had an accuracy of 0.90, a precision of 0.86, a recall of 1.00, and an F-measure of 0.92. Visualization results show that the DL models focused on the epineurium of the ulnar nerve and the surrounding soft tissue. The proposed technique enables the accurate prediction of CuTS without the need to measure CSA.

Outcome of Simple Decompression of Primary Cubital Tunnel Syndrome Based on Patient-Reported Outcome Measurements

PURPOSE

To evaluate the patient-reported outcome measures of patients with primary cubital tunnel syndrome and to assess whether they are affected by preoperative symptom severity.

METHODS

Patients who underwent simple decompression for primary cubital tunnel syndrome were selected from a prospectively maintained database. Outcome measurements consisted of the Boston Carpal Tunnel Questionnaire at intake and at 3 and 6 months after surgery. Also, 6 months after surgery, the patients received a question about their satisfaction with the treatment result. To determine a possible influence of preoperative symptom severity on postoperative outcomes, the sample was divided into quartiles based on symptom severity at intake.

RESULTS

One hundred and forty-five patients were included in the final analysis. On average, all patients improved on the Boston Carpal Tunnel Questionnaire. The subgroup of patients with the mildest symptoms at intake did not improve significantly on symptom severity but did improve significantly on their functional status. In addition, the patients with the most severe symptoms at intake did improve on both aspects. Moreover, no difference in satisfaction with treatment result between the severity of symptoms at intake was found.

CONCLUSIONS

The patients with the mildest symptoms at intake may not improve on symptom severity, but they do improve on functional status after simple decompression for cubital tunnel syndrome. In addition, patients with the most severe symptoms at intake do improve on both symptom severity and functional status. Moreover, all patients reported to be equally satisfied with the treatment result, which suggests that satisfaction is not dependent on the symptom severity at intake. Even those patients with both the mildest symptoms before surgery and the least improvement still seem to benefit from simple decompression.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Endoscopic cubital tunnel decompression: state of the art

Cubital tunnel syndrome is a common compressive neuropathy of the upper limb. Surgical decompression is indicated for patients who failed conservative therapy. Decompression in situ has shown to achieve comparable outcomes as decompression with anterior transposition in idiopathic cubital tunnel syndrome. Endoscopic cubital tunnel decompression has gained popularity in recent years, as surgeons can attain decompression of the ulnar nerve along its course using a small incision. Results from randomised controlled studies and systematic reviews, comparing endoscopic with open decompression in situ, are promising. Cases in which anterior transposition of the ulnar nerve is needed, an endoscopic technique can still be used by creating an additional volar portal, for the mobilisation of ulnar nerve. Early short-term results are encouraging. Further adequately powered, prospective, preferably double-blinded, randomised study are needed.

Intraneural ganglion cyst of the ulnar nerve causing cubital tunnel syndrome masquerading a peripheral nerve abscess of a neuritic leprosy

Cubital tunnel syndrome is a common entrapment neuropathy affecting the ulnar nerve. Intraneural ganglion cyst and nerve abscess due to leprosy can cause cubital tunnel syndrome. In this article, we are presenting a case of cubital tunnel syndrome caused due to an intraneural ganglion cyst in a 48-year-old lady. It had produced some diagnostic confusion due to its clinical similarity with nerve abscess. This is the first report of a case of an intraneural ganglion cyst of the ulnar nerve masquerading the diagnosis of a nerve abscess.