Neuromuscular ultrasound in common entrapment neuropathies

Neuromuscular ultrasound involves the use of high-resolution ultrasound to image the peripheral nervous system of patients with suspected neuromuscular diseases. It complements electrodiagnostic studies well by providing anatomic information regarding nerves, muscles, vessels, tendons, ligaments, bones, and other structures that cannot be obtained with nerve conduction studies and electromyography. Neuromuscular ultrasound has been studied extensively over the past 10 years and has been used most often in the assessment of entrapment neuropathies. This review focuses on the use of neuromuscular ultrasound in 4 of the most common entrapment neuropathies: carpal tunnel syndrome, ulnar neuropathy at the elbow and wrist, and fibular neuropathy at the knee.

Incidence of re-operation and subjective outcome following in situ decompression of the ulnar nerve at the cubital tunnel

The purpose of this investigation was to determine the failure rate of in situ decompression for cubital tunnel syndrome as determined by the need for additional surgery. We performed a comprehensive chart review of 56 adult patients who had undergone in situ decompression for cubital tunnel syndrome in 69 extremities with more than 1 year follow-up. The patients completed a comprehensive questionnaire concerning preoperative and postoperative pain, numbness, and weakness. After decompression, symptoms were improved substantially or resolved. Five limbs (7%) with persistent symptoms postoperatively were treated successfully with anterior submuscular transposition. These data suggest that in situ decompression of the ulnar nerve is a reliable treatment for cubital tunnel syndrome and has a low failure rate. The uncommon patient with continued symptoms after decompression can be treated effectively with transposition of the ulnar nerve.

The Management of Cubital Tunnel Syndrome

Symptomatic cubital tunnel syndrome is a condition that frequently prompts patients to seek hand surgical care. Although cubital tunnel syndrome is readily diagnosed, achieving complete symptom resolution remains challenging. This article reviews related anatomy, clinical presentation, and current management options for cubital tunnel syndrome with an emphasis on contemporary outcomes research.

Peripheral nerve ultrasound in amyotrophic lateral sclerosis phenotypes

INTRODUCTION

In this study we sought to determine the cross-sectional area (CSA) of peripheral nerves in patients with distinct subtypes of amyotrophic lateral sclerosis (ALS).

METHODS

Ulnar and median nerve ultrasound was performed in 78 ALS patients [classic, n = 21; upper motor neuron dominant (UMND), n = 14; lower motor neuron dominant (LMND), n = 20; bulbar, n = 15; primary lateral sclerosis (PLS), n = 8] and 18 matched healthy controls.

RESULTS

Compared with controls, ALS patients had significant, distally pronounced reductions of ulnar CSA (forearm/wrist level) across all disease groups, except for PLS. Median nerve CSA (forearm/wrist level) did not differ between controls and ALS.

CONCLUSION

Ulnar nerve ultrasound in ALS subgroups revealed significant differences in distal CSA values, which suggests it has value as a marker of LMN involvement. Its potential was particularly evident in the UMND and PLS groups, which can be hard to separate clinically, yet their accurate separation has major prognostic implications.

Predicting Revision Following In Situ Ulnar Nerve Decompression for Patients With Idiopathic Cubital Tunnel Syndrome

PURPOSE

To determine the incidence of revision and potential risk factors for needing revision surgery following in situ ulnar nerve decompression for patients with idiopathic cubital tunnel syndrome (CTS).

METHODS

We conducted a retrospective chart review of all patients treated at 1 specialty hand center with an open in situ ulnar nerve decompression for idiopathic CTS from January 2006 through December 2010. Revision incidence was determined by identifying patients who underwent additional surgeries for recurrent or persistent ulnar nerve symptoms. Bivariate analysis was performed to determine which variables had a significant influence on the need for revision surgery.

RESULTS

Revision surgery was required in 3.2% (7 of 216) of all cases. Age younger than 50 years at the time of index decompression was the lone significant predictor of need for revision surgery. Other patient factors, including gender, diabetes, smoking history, and workers' compensation status were not predictive of the need for revision surgery. Disease-specific variables including nerve conduction velocities, McGowan grading, and predominant symptom type were also not predictive of revision.

CONCLUSIONS

For patients with idiopathic CTS, the risk of revision surgery following in situ ulnar nerve decompression is low. However, this risk was increased in patients who were younger than 50 years at the time of the index procedure. The findings of this study suggest that, in the absence of underlying elbow arthritis or prior elbow trauma, in situ ulnar nerve decompression is an effective, minimal-risk option for the initial surgical treatment of CTS.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic III.

Cross-sectional area reference values for peripheral nerve ultrasound in adults: a systematic review and meta-analysis-Part I: Upper extremity nerves

BACKGROUND AND PURPOSE

Measurement of the cross-sectional area (CSA) of peripheral nerves using ultrasound is useful in the evaluation of focal lesions like entrapment syndromes and inflammatory polyneuropathies. Here, a systematic review and meta-analysis of published CSA reference values for upper extremity nerves was performed.

METHODS

Available to date nerve ultrasound studies on healthy adults were included and a meta-analysis for CSA was provided of the following nerves: median nerve at the wrist, forearm, upper arm; ulnar nerve at the Guyon's canal, forearm, elbow, upper arm; radial nerve at the upper arm. Regression and correlation analyses for age, gender, height, weight, geographic continents and publication year are reported.

RESULTS

Seventy-four studies with 4186 healthy volunteers (mean age 42.7 years) and 18,226 examined nerve sites were included. The calculated mean pooled CSA of the median nerve at the wrist was 8.3 mm2 (95% confidence interval [95% CI] 7.9-8.7, n = 4071), at the forearm 6.4 mm2 (95% CI 5.9-6.9, n = 3021), at the upper arm 8.3 mm2 (95% CI 7.5-9.0, n = 1388), of the ulnar nerve at the Guyon's canal 4.1 mm2 (95% CI 3.6-4.6, n = 1688), at the forearm 5.2 mm2 (95% CI 4.8-5.7, n = 1983), at the elbow 5.9 mm2 (95% CI 5.4-6.5, n = 2551), at the upper arm 6.6 mm2 (95% CI 5.1-6.1, n = 1737) and of the radial nerve 5.1 mm2 (95% CI 4.0-6.2, n = 1787). Substantial heterogeneity across studies (I2 > 50%) was found only for the radial nerve. Subgroup analysis revealed a positive effect of age for the median nerve at the wrist and for height and weight for different sites of the ulnar nerve.

CONCLUSION

The first meta-analysis on CSA reference values for the upper extremities with no or only low heterogeneity of reported CSA values in most nerve sites is provided. Our data facilitate the goal of an international standardized evaluation protocol.

Endoscopic Versus Open Cubital Tunnel Release: A Systematic Review and Meta-Analysis

BACKGROUND

Several surgical techniques exist for treatment of cubital tunnel syndrome. Endoscopic cubital tunnel release (ECTuR) has been recently reported as a promising minimally invasive technique. This study aims to compare outcomes and complications of open cubital tunnel release (OCTuR) and ECTuR in the treatment of idiopathic cubital tunnel syndrome.

METHODS

A systematic review of the literature (1980-2014) identified 118 citations. Studies including adults with idiopathic cubital tunnel treated exclusively by ECTuR or OCTuR were included. Outcomes of interest were postoperative grading, complications, number of reoperations, and the need for intraoperative conversion to another technique. Postoperative outcomes were combined into a uniform scale with 4 categories: "excellent," "good," "fair," and "poor."

RESULTS

Twenty studies met the inclusion criteria (17 observational and 3 comparative), representing 425 open and 556 endoscopic decompressions. In the open group, 79.8% experienced "good" or "excellent" results with 12% complication rate and 2.8% reoperation rate. In the endoscopic group, 81.8% experienced "good" or "excellent" results with 9% complication rate and 1.6% reoperation rate. Meta-analysis of 3 comparative studies demonstrated a significantly lower overall complication rate with ECTuR. Subgroup analysis of complications revealed a significantly higher incidence of scar tenderness and elbow pain with OCTuR.

CONCLUSIONS

The current study demonstrates similar effectiveness between the endoscopic (ECTuR) and open (OCTuR) techniques for treatment of idiopathic cubital tunnel syndrome with similar outcomes, complication profiles, and reoperation rates.

Open surgical elbow contracture release after trauma: results and recommendations

BACKGROUND

Post-traumatic elbow contracture is a debilitating complication after elbow trauma. The purpose of this study was to characterize the affected patient population, operative management, and outcomes after operative elbow contracture release for treatment of post-traumatic elbow contracture.

METHODS

A retrospective record review was conducted to identify all patients who underwent post-traumatic elbow contracture release performed by 1 of 3 surgeons at one academic medical center. Patient demographics, injuries, operative details, outcomes, and complications were recorded.

RESULTS

The study included 103 patients who met inclusion criteria. At the time of contracture release, patients were a mean age of 45.2 ± 15.6 years. Contracture release resulted in a significant mean increase to elbow extension/flexion arc of motion of 52° ± 18° (P < .0005). Not including recurrence of contracture, a subsequent complication occurred in 10 patients (10%). Radiographic recurrence of heterotopic ossification (HO) occurred in 14 patients (14%) after release. Ten patients (11%) elected to undergo a secondary operation to gain more motion.

CONCLUSION

Soft tissue and bony elbow contracture release is effective. Patients with post-traumatic elbow contracture can make significant gains to their arc of motion after contracture release surgery and can expect to recover a functional elbow arc of motion. Patients with severe preoperative contracture may benefit from concomitant ulnar nerve decompression. HO prophylaxis did not affect the rate of HO recurrence or ultimate elbow range of motion. However, patients must be counseled that contracture may reoccur, and some patients may require or elect to have more than one procedure to achieve functional motion.

An anatomical basis for endoscopic cubital tunnel release and associated clinical outcomes

PURPOSE

To study the ulnar nerve in fresh-frozen cadavers as related to endoscopic release of the cubital tunnel and to present a retrospective review of patients treated with decompression via endoscopic visualization.

METHODS

To further our understanding of relevant anatomy, we dissected 26 cadaver limbs. We paid special attention to fascial membranes as potential sites of constriction as well as the position of nerves, vessels, and aberrant anatomy. These findings facilitated our understanding of the extent of release in 80 patients (92 cases) with endoscopic cubital tunnel simple decompression. Outcome measures included Disabilities of the Arm, Shoulder, and Hand score, Gabel and Amadio score, and grip and pinch strengths.

RESULTS

We noted fascial bands proximal to the medial epicondyle in 12 of 26 cadaver specimens, 2 of which could be the so-called arcade of Struthers. We observed a high degree of variability in the anatomy of the flexor pronator aponeurosis distal to the medial epicondyle. Where present (n = 10), medial antebrachial cutaneous nerve branches crossed the ulnar nerve at an average distance of 2.9 cm from the medial epicondyle (range, 1.0-4.5 cm). Aberrant structures were noted in 8 of the 26 specimens, including an anconeus epitrochlearis muscle in 2 specimens, a basilic vein crossing the ulnar nerve in 4 specimens, and an accessory origin of the medial head of the triceps from the medial intermuscular septum in 2 specimens. In the clinical portion of this study, the average Disabilities of the Arm, Shoulder, and Hand score before surgery was 49 (n = 34) and after surgery was 25 (n = 56). The Gabel and Amadio outcome scores were 24 excellent, 40 good, 25 fair, and 3 poor (n = 92). Average follow-up was 8.2 months (range, 0.1-35 mo).

CONCLUSIONS

Cadaveric dissections shed light on vulnerable anatomical structures during release, including branches of the medial antebrachial cutaneous nerve, ulnar nerve, brachial artery, fascial bands, and basilic vein. The high degree of anatomical variability in this study highlights the advantage of endoscopic visualization in allowing surgeons to minimize surgical trauma.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Ulnar Nerve In Situ Decompression versus Transposition for Idiopathic Cubital Tunnel Syndrome: An Updated Meta-Analysis

Purpose Evidence for the superiority of in situ simple decompression (SD) versus ulnar nerve transposition (UNT) for cubital tunnel syndrome remains controversial. The purpose of this study was to compare the clinical improvement, complication rate, and revision rate of SD versus UNT using the available evidence. Materials and Methods We performed a literature search of relevant publications using PubMed, SCOPUS, Cochrane Library, and Springer Link. Inclusion criteria included (1) adult patients >18 years of age, (2) idiopathic cubital tunnel syndrome, (3) primary comparison studies including both SD versus UNT with discrete data for each procedure, (4) average follow-up of at least 2 months, and (5) a full English language manuscript available. Odds ratios of improvement, complications, and revision surgery after SD compared with UNT were calculated. Data were analyzed using both fixed and random effects models, and studies were assessed for publication bias and heterogeneity. Results A total of 1,511 articles from 1970 to 2017 were identified before inclusion, and exclusion criteria were applied. Ultimately 17 studies met the inclusion criteria and included 2,154 procedures. Of these, 1,040 were SD, and 1,114 were UNT procedures. Study heterogeneity was low. Odds ratios of clinical improvement and revision surgery with SD versus UNT were not significantly different. The odds ratio of complications with SD versus UNT was 0.449 (95% confidence interval [CI] of 0.290-0.695) and 0.469 (95% CI of 0.297-0.738) for fixed and random effect models, respectively. The difference in complications between SD versus UNT was significant ( P < 0.001). Conclusion There is no statistically significant difference in clinical outcomes or rate of revision surgery between SD versus UNT. However, there were significantly more complications with UNT. The current body of evidence regarding cubital tunnel syndrome lacks prospective, randomized, controlled trials, uniform reporting of indications, and standardized outcome scoring.

Anatomical relationships and branching patterns of the dorsal cutaneous branch of the ulnar nerve

PURPOSE

To describe the variable branching patterns of the dorsal cutaneous branch of the ulnar nerve (DCBUN) relative to identifiable anatomical landmarks on the ulnar side of the wrist.

METHODS

We dissected the ulnar nerve in 28 unmatched fresh-frozen cadavers to identify the DCBUN and its branches from its origin to the level of the metacarpophalangeal joints. The number and location of branches of the DCBUN were recorded relative to the distal ulnar articular surface. Relationships to the subcutaneous border of the ulna, the pisotriquetral joint, and the extensor carpi ulnaris tendon were defined in the pronated wrist.

RESULTS

On average, 2 branches of the DCBUN were present at the level of the distal ulnar articular surface (range, 1-4). On average, 2.2 branches were present 2 cm distal to the ulnar articular surface (range, 1-4). At least 1 longitudinal branch crossed dorsal to the extensor carpi ulnaris tendon prior to its insertion at the base of the fifth metacarpal in 23 of 28 specimens (82%). In 27 of 28 specimens (96%), all longitudinal branches of the DCBUN coursed between the dorsal-volar midpoint of the subcutaneous border of the ulna and the pisotriquetral joint. In 20 of 28 specimens (71%), a transverse branch of the DCBUN to the distal radioulnar joint was present.

CONCLUSIONS

During exposure of the dorsal and ulnar areas of the wrist, identification and protection of just a single branch of the DCBUN are unlikely to ensure safe dissection because multiple branches normally are present. The 6U, 6R, and ulnar midcarpal arthroscopy portals may place these branches at risk. In the pronated forearm, the area between the DCBUN and the pisotriquetral joint contained all longitudinal branches of the DCBUN in 96% of specimens.

CLINICAL RELEVANCE

During surgery involving the dorsal and ulnar areas of the wrist, multiple longitudinal branches and a transverse branch of the DCBUN are normally present and must be respected.

Supercharge End-to-Side Nerve Transfer: Systematic Review

Background: To decrease the time to reinnervation of the intrinsic motor end plates after high ulnar nerve injuries, a supercharged end-to-side (SETS) anterior interosseous to ulnar motor nerve transfer has been proposed. The purpose of this study was to compile and review the indications, outcomes, and complications of SETS anterior interosseous to ulnar motor nerve transfer. Methods: A literature search was performed, identifying 73 papers; 4 of which met inclusion and exclusion criteria, including 78 patients. Papers included were those that contained the results of SETS between the years 2000 and 2018. Data were pooled and analyzed focusing on the primary outcomes: intrinsic muscle recovery and complications. Results: Four studies with 78 patients met inclusion and exclusion criteria. Most patients (33.3%) underwent SETS for an ulnar nerve lesion in continuity, the average age was 46.5 years, and the average follow-up was 10 months. The average duration of symptoms before surgery was 99 weeks, all patients had weakness and numbness, nearly all (96%) had atrophy, and half (53%) had pain. Grip and key pinch strength improved 202% and 179%, respectively, from the preoperative assessment. The vast majority (91.9%) recovered intrinsic function at an average of 3.7 months. Other than 8% of patients who did not recover intrinsic strength, no other complications were reported in any of the 78 patients. Conclusions: The SETS is a successful procedure with low morbidity, which may restore intrinsic function in patients with proximal nerve injuries.

The cubital tunnel: a radiologic and histotopographic study

Entrapment of the ulnar nerve at the elbow is the second most common compression neuropathy in the upper limb. The present study evaluates the anatomy of the cubital tunnel. Eighteen upper limbs were analysed in unembalmed cadavers using ultrasound examination in all cases, dissection in nine cases, and microscopic study in nine cases. In all cases, thickening of the fascia at the level of the tunnel was found at dissection. From the microscopic point of view, the ulnar nerve is a multifascicular trunk (mean area of 6.0 ± 1.5 mm(2) ). The roof of the cubital tunnel showed the presence of superimposed layers, corresponding to fascial, tendineous and muscular layers, giving rise to a tri-laminar structure (mean thickness 523 ± 235 μm). This multilayered tissue was hyperechoic (mean thickness 0.9 ± 0.3 mm) on ultrasound imaging. The roof of the cubital tunnel is elastic, formed by a myofascial trilaminar retinaculum. The pathological fusion of these three layers reduces gliding of the ulnar nerve during movements of the elbow joint. This may play a role in producing the symptoms typical of cubital tunnel syndrome. Independent from the surgical technique, decompression should span the ulnar nerve from the triceps brachii muscle to the flexor carpi ulnaris fascia.

Tissue-engineered rhesus monkey nerve grafts for the repair of long ulnar nerve defects: similar outcomes to autologous nerve grafts

Acellular nerve allografts can help preserve normal nerve structure and extracellular matrix composition. These allografts have low immunogenicity and are more readily available than autologous nerves for the repair of long-segment peripheral nerve defects. In this study, we repaired a 40-mm ulnar nerve defect in rhesus monkeys with tissue-engineered peripheral nerve, and compared the outcome with that of autograft. The graft was prepared using a chemical extract from adult rhesus monkeys and seeded with allogeneic Schwann cells. Pathomorphology, electromyogram and immunohistochemistry findings revealed the absence of palmar erosion or ulcers, and that the morphology and elasticity of the hypothenar eminence were normal 5 months postoperatively. There were no significant differences in the mean peak compound muscle action potential, the mean nerve conduction velocity, or the number of neurofilaments between the experimental and control groups. However, outcome was significantly better in the experimental group than in the blank group. These findings suggest that chemically extracted allogeneic nerve seeded with autologous Schwann cells can repair 40-mm ulnar nerve defects in the rhesus monkey. The outcomes are similar to those obtained with autologous nerve graft.

Ulnar nerve strain at the elbow in patients with cubital tunnel syndrome: effect of simple decompression

Simple decompression of the ulnar nerve at the elbow has not been shown to reduce nerve strain in cadavers. In this study, ulnar nerve strain at the elbow was measured intraoperatively in 11 patients with cubital tunnel syndrome, before and after simple decompression. Statistical analysis was performed using a paired Student's t-test. Mean ulnar nerve strain before and after simple decompression was 30.5% (range 9% to 69%) and 5.5% (range -2% to 11%), respectively; this difference was statistically significant (p < 0.01) with a statistical power of 96%. Simple decompression reduced ulnar nerve strain in all patients by an average of 24.5%. Our results suggest that the pathophysiology of cubital tunnel syndrome may be multifactorial, being neither a simple compression neuropathy nor a simple traction neuropathy, and simple decompression may be a favourable surgical procedure for cubital tunnel syndrome in terms of decompression and reduction of strain in the ulnar nerve.

Optimal Measurement Level and Ulnar Nerve Cross-Sectional Area Cutoff Threshold for Identifying Ulnar Neuropathy at the Elbow by MRI and Ultrasonography

PURPOSE

Imaging criteria for diagnosing compressive ulnar neuropathy at the elbow (UNE) have recently been established as the maximum ulnar nerve cross-sectional area (UNCSA) upon magnetic resonance imaging (MRI) and/or ultrasonography (US). However, the levels of maximum UNCSA and diagnostic cutoff values have not yet been established. We therefore analyzed UNCSA by MRI and US in patients with UNE and in controls.

METHODS

We measured UNCSA at 7 levels in 30 patients with UNE and 28 controls by MRI and at 15 levels in 12 patients with UNE and 24 controls by US. We compared UNCSA as determined by MRI or US and determined optimal diagnostic cutoff values based on receiver operating characteristic curve analysis.

RESULTS

The UNCSA was significantly larger in the UNE group than in controls at 3, 2, 1, and 0 cm proximal and 1, 2, and 3 cm distal to the medial epicondyle for both modalities. The UNCSA was maximal at 1 cm proximal to the medial epicondyle for MRI (16.1 ± 3.5 mm²) as well as for US (17 ± 7 mm²). A cutoff value of 11.0 mm² for MRI and US was found to be optimal for differentiating between patients with UNE and controls, with an area under the receiver operating characteristic curve of 0.95 for MRI and 0.96 for US. The UNCSA measured by MRI was not significantly different from that by US. Intra-rater and interrater reliabilities for UNCSA were all greater than 0.77. The UNCSA in the severe nerve dysfunction group of 18 patients was significantly larger than that in the mild nerve dysfunction group of 12 patients.

CONCLUSIONS

By measuring UNCSA with MRI or US at 1 cm proximal to the ME, patients with and without UNE could be discriminated at a cutoff threshold of 11.0 mm² with high sensitivity, specificity, and reliability.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Subcutaneous vs Submuscular Ulnar Nerve Transposition in Moderate Cubital Tunnel Syndrome

Background:

The surgical treatment of Cubital tunnel syndrome (CubTS) is still a matter of debate. No consensus exists about the necessity of anterior transposition of the ulnar nerve after decompression. However, this technique is fairly common in clinical practice.

Material and Methodology:

In the present study we compared the operative technique (incision length, operative time), postoperative care (postoperative pain and complications) and the outcome between subcutaneous transposition and submuscular transposition of the ulnar nerve as two surgical modalities in treating moderate CubTS.

Between March 2004 and March 2007, twenty six patients with moderate CubTS (according to Dellon’s grading system) were stratified according to age and gender into these two surgical techniques. The two groups were prospectively followed up 2 weeks, 6 months and 12 months postoperatively by the same observer and the operation outcome was assessed using the Bishop rating system.

Results:

We found that the subcutaneous transposition of the ulnar nerve was associated with shorter incision, shorter operative time, less postoperative pain, less postoperative complication and better outcome compared with the submuscular transposition.

Conclusion:

The authors recommend the subcutaneous technique when considering anterior transposition of the ulnar nerve in treating moderate CubTS.

The Management of Persistent and Recurrent Cubital Tunnel Syndrome

Cubital tunnel syndrome (CuTS) is the second most common compressive neuropathy in the upper extremity. There are considerable diagnostic and therapeutic challenges associated with treating patients after a failed primary procedure for CuTS. Distinguishing cases of recurrence versus persistence and identifying concomitant pathology can guide treatment. Conditions that mimic CuTS must be carefully ruled out and coexisting dysfunction of the medial antebrachial cutaneous nerve needs to be addressed. Results of revision procedures are not as reliable as primary procedures for CuTS; however, improvements in pain and paresthesias are noted in approximately 75% of patients. Nerve wraps represent a promising adjuvant treatment option, but long-term outcome data are lacking. External neurolysis and anterior transposition after failed CuTS procedures are supported by case series; multicenter, prospective randomized trials are needed to guide treatment further and improve outcomes.

Dynamic analysis of the ulnar nerve in the cubital tunnel using ultrasonography

BACKGROUND

We investigated the dynamics of the ulnar nerve during elbow flexion and the relationships between these dynamics and the morphology of the ulnar nerve groove in healthy individuals.

MATERIALS AND METHODS

Twenty healthy volunteers (40 elbows) underwent ultrasonographic examination of the ulnar nerve at the elbow. We measured the breadth and depth of the ulnar nerve groove at 90° of elbow flexion and calculated the depth-to-breadth ratio. We recorded the distance from the trochlea of the humerus to the nerve and the short-axis diameter of the nerve at 30°, 60°, 90°, and 120° of elbow flexion. We calculated the medial shift and flattening of the ulnar nerve at each angle relative to 30° of flexion, compared the values among the different angles, and compared the depth-to-breadth ratio with the location, medial shift, and flattening ratio of the ulnar nerve.

RESULTS

The medial shift was significantly greater at 120° than at other angles (P < .001). Flattening increased with increasing elbow flexion and was significantly different at 60°, 90°, and 120° (all P < .001). The flattening ratios were significantly correlated with the depth-to-breadth ratio at 120° (r = -0.43, P = .005).

CONCLUSIONS

The ulnar nerve moves medially and is flattened with the elbow flexed between 90° and 120°. When the ulnar nerve groove is shallow, high degrees of elbow flexion result in flattening of the ulnar nerve in the groove.

Transfer of a Terminal Motor Branch Nerve to the Flexor Carpi Ulnaris for Triceps Reinnervation: Anatomical Study and Clinical Cases

PURPOSE

To analyze the anatomical feasibility of transferring a motor branch nerve to the flexor carpi ulnaris (FCU) to the triceps upper medial head motor branch (UMHM) and to report the resultant outcome of the restoration of elbow extension in 5 patients with extensive brachial plexus injury.

METHODS

The ulnar and radial nerves were dissected in 10 cadavers. We measured the length and diameter of the branches to the FCU and the UMHM branch and counted the axons. Then, 5 male patients, mean age 30 years, underwent FCU nerve branch transfer for reconstruction of elbow extension. Elbow flexion was restored via a median nerve branch to biceps transfer.

RESULTS

Mean UMHM nerve length and diameter were 86 and 1.5 mm, respectively. Mean number of branches to the FCU muscle was 2.9. Mean FCU nerve length and diameter were 50 and 1.0 mm, respectively. Mean number of myelinated fibers was 818 and 743 for the UMHM and the longest branch to the FCU, respectively. Coaptation between nerves was possible without tension. All patients recovered functional active elbow extension at a mean follow-up of 19 months with a British Medical Research Council score of M4. After surgery, all patients retained a functional FCU with a British Medical Research Council score of M4.

CONCLUSIONS

Nonselective ulnar nerve fascicles at the root of the limb might not be adequate to restore elbow extension when combined with a median nerve branch transfer for elbow flexion. A selective distal ulnar motor fascicle such as a FCU motor branch could be harvested and connected to a triceps branch to restore elbow extension. Such a nerve transfer would also allow for later transfer of the still functional FCU tendon to the digital extensors.

CLINICAL RELEVANCE

For patients with extensive brachial plexus injury and a preserved medial cord, transferring a motor branch nerve to the FCU is an effective technique for the reconstruction of elbow extension.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Double Motor Nerve Transfer for All Finger Flexion in Cervical Spinal Cord Injury: An Anatomical Study and a Clinical Report

PURPOSE

To explore the feasibility of restoring all finger flexion after a cervical spinal cord injury.

METHODS

Double nerve transfer was conducted in 22 cadaver upper extremities. Donor nerves were the brachialis branch of the musculocutaneous nerve and the extensor carpi radialis brevis (ECRB) branches of the radial nerve. Recipient nerves were the anterior interosseous nerve (AIN) and the flexor digitorum profundus (FDP) branch of ulnar nerve (ulnar-FDP). Nerve transfers were evaluated on 3 parameters: surgical feasibility, donor-to-recipient axon count ratio, and distance from the coaptation site to the muscle entry of recipient nerve. A complete C6 spinal cord injury reconstruction was accomplished in a patient using a double nerve transfer of ECRB to ulnar-FDP and brachialis to AIN.

RESULTS

In the cadaver study, nerve transfers from ECRB to AIN, brachialis to AIN, and ECRB to ulnar-FDP were all feasible. The transfer from the brachialis to ulnar-FDP was not possible. Mean myelinated axon counts of AIN, brachialis, ulnar-FDP, and ECRB were 2,903 ± 1049, 1,497 ± 606, 753 ± 364, and 567 ± 175, respectively. The donor-to-recipient axon count ratios of ECRB to AIN, brachialis to AIN, and ECRB to ulnar-FDP were 0.24 ± 0.15, 0.55 ± 0.38, and 0.98 ± 0.60, respectively. The distance from coaptation of the ECRB to the ulnar-FDP muscle entry was shorter than for the other nerve transfers (54 ± 14.29 mm). At 18 months, there was restoration of flexion in all fingers and functional improvement from double nerve transfer of the brachialis to the AIN and the ECRB to the ulnar-FDP.

CONCLUSIONS

Restoration of all finger flexion may be feasible by the ECRB to ulnar-FDP and brachialis to AIN double nerve transfer.

CLINICAL RELEVANCE

Double nerve transfer can be used in C6-C7 spinal cord injury and patients with lower arm-type brachial plexus injury who have no finger flexion but have good brachialis and ECRB.

Risk factors for revision surgery following isolated ulnar nerve release at the cubital tunnel: a study of 25,977 cases

BACKGROUND

The literature investigating risk factors for failure after decompression of the ulnar nerve at the elbow (cubital tunnel release [CuTR]) is limited. The purpose of this study was to identify risk factors for failure of isolated CuTR, defined as progression to subsequent ipsilateral revision surgery.

METHODS

The 100% Medicare Standard Analytic Files from 2005 to 2012 were queried for patients undergoing CuTR. Patients undergoing any concomitant procedures were excluded. A multivariate binomial logistic regression analysis was used to evaluate patient-related risk factors for ipsilateral revision surgery. Adjusted odds ratios (ORs) and 95% confidence intervals were calculated for each risk factor.

RESULTS

A total of 25,977 patients underwent primary CuTR, and 304 (1.4%) of those with ≥2 years of follow-up required revision surgery. Although the rate of primary procedures is on the rise (P = .002), the revision rate remains steady (P = .148). Significant, independent risk factors for revision surgery included age <65 years (OR, 1.5; P < .001), obesity (OR, 1.3; P = .022), morbid obesity (OR, 1.3; P = .044), tobacco use (OR, 2.0; P < .001), diabetes (OR, 1.3; P = .011), hyperlipidemia (OR, 1.2; P = .015), chronic liver disease (OR, 1.6; P = .001), chronic anemia (OR, 1.6; P = .001), and hypercoagulable disorder (OR, 2.1; P = .001).

CONCLUSIONS

The incidence of failure requiring ipsilateral revision surgery after CuTR remained steadily low (1.4%) during the study period. There are numerous patient-related risk factors that are independently associated with an increased risk for revision surgery, the most significant of which are tobacco use, younger age, hypercoagulable disorder, liver disease, and anemia.

Movement of the ulnar nerve at the elbow: a sonographic study

OBJECTIVES

The aim of this study was to measure the degree of movement of the ulnar nerve in the cubital tunnel using sonography in patients with ulnar neuropathy at the elbow compared to a healthy control group.

METHODS

We examined the ulnar nerve in the cubital tunnel using sonography with the elbow extended and then flexed in 26 patients with ulnar neuropathy and 13 control participants. The distance from the ulnar nerve to the skin, medial epicondyle, and tip of olecranon at the inlet of the cubital tunnel and the distance from the ulnar nerve to the skin and olecranon recess at the outlet of the cubital tunnel were measured when the elbow was extended and flexed, respectively. Displacement of the ulnar nerve during elbow extension and flexion between patients with ulnar neuropathy and controls was compared.

RESULTS

There was significantly greater displacement of the ulnar nerve to the medial epicondyle at the inlet of the cubital tunnel in the patients with ulnar neuropathy (mean ± SD, 4.22 ± 3.79 mm) compared to the controls (1.76 ± 1.51 mm) during elbow extension and flexion (P = .008).

CONCLUSIONS

A significantly greater degree of movement of the ulnar nerve occurs in patients with ulnar neuropathy at the elbow compared to healthy people, as determined by sonography.

Examination of the elbow: current concepts

The elbow's complex anatomy and synergism of bony and ligamentous stabilizers make physical examination challenging. Adequate elbow assessment is essential for accurate diagnosis and initiating proper treatment. Isolated elbow injuries are rare; fractures should be interpreted as proxies for associated, often unappreciated, soft tissue injuries. A careful elbow examination informs the need for and interpretation of radiological studies, including fluoroscopy, magnetic resonance imaging, and computed tomography scanning.