Double entrapment neuropathy of the ulnar nerve at the elbow and the wrist : double crush syndrome?

BACKGROUND: Double crush syndrome refers to a nerve in the proximal region being compressed, affecting its proximal segment. Instances of this syndrome involving ulnar and cubital canals during ulnar neuropathy are rare. Diagnosis solely through clinical examination is challenging. Although electromyography (EMG) and nerve conduction studies (NCS) can confirm neuropathy, they do not incorporate inching tests at the wrist, hindering diagnosis confirmation. We recently encountered eight cases of suspected double compression of ulnar nerve, reporting these cases along with a literature review. METHODS: The study included 5 males and 2 females, averaging 45.6 years old. Among them, 4 had trauma history, and preoperative McGowan stages varied. Ulnar neuropathy was confirmed in 7 cases at both cubital and ulnar canal locations. Surgery was performed for 4 cases, while conservative treatment continued for 3 cases. RESULTS: In 4 cases with wrist involvement, 2 showed ulnar nerve compression by a fibrous band, and 1 had nodular hyperplasia. Another case displayed ulnar nerve swelling with muscle covering. Among the 4 surgery cases, 2 improved from preoperative McGowan stage IIB to postoperative stage 0, with significant improvement in subjective satisfaction. The remaining 2 cases improved from stage IIB to IIA, respectively, with moderate improvement in subjective satisfaction. In the 3 cases receiving conservative treatment, satisfaction was significant in 1 case and moderate in 2 cases. Overall, there was improvement in hand function across all 7 cases. CONCLUSION: Typical outpatient examinations make it difficult to clearly differentiate the two sites, and EMG tests may not confirm diagnosis. Therefore, if a surgeon lacks suspicion of this condition, diagnosis becomes even more challenging. In cases with less than expected postoperative improvement in clinical symptoms of cubital tunnel syndrome, consideration of double crush syndrome is warranted. Additional tests and detailed EMG tests, including inching tests at the wrist, may be necessary. We aim to raise awareness double crush syndrome with ulnar nerve, reporting a total of 7 cases to support this concept.

Assessing ulnar neuropathy at the elbow using magnetoneurography.

OBJECTIVE: To measure neuromagnetic fields of ulnar neuropathy patients at the elbow after electrical stimulation and evaluate ulnar nerve function at the elbow with high spatial resolution. METHODS: A superconducting quantum interference device magnetometer system recorded neuromagnetic fields of the ulnar nerve at the elbow after electrical stimulation at the wrist in 16 limbs of 16 healthy volunteers and 21 limbs of 20 patients with ulnar neuropathy at the elbow. After artifact removal, neuromagnetic field signals were processed into current distributions, which were superimposed onto X-ray images for visualization. RESULTS: Based on the results in healthy volunteers, conduction velocity of 30 m/s or 50% attenuation in current amplitude was set as the reference value for conduction disturbance. Of the 21 patient limbs, 15 were measurable and lesion sites were detected, whereas 6 limbs were unmeasurable due to weak neuromagnetic field signals. Seven limbs were deemed normal by nerve conduction study, but 5 showed conduction disturbances on magnetoneurography. CONCLUSIONS: Measuring the magnetic field after nerve stimulation enabled visualization of neurophysiological activity in patients with ulnar neuropathy at the elbow and evaluation of conduction disturbances. SIGNIFICANCE: Magnetoneurography may be useful for assessing lesion sites in patients with ulnar neuropathy at the elbow.

Comprehensive analysis and classification of retrocondylar ulnar groove morphology using CT imaging in an average population of adults.

PURPOSE: Anatomical variations of the concave shaped retrocondylar ulnar groove (RUG) can contribute to ulnar nerve instability. However, there are currently limited available standardized data describing the anatomy of the RUG based on radiologic imaging, such as computed tomography (CT). This study aims to provide a comprehensive description and classification of RUG anatomy based on RUG angle measurements. METHODS: 400 CT scans of the elbows of adults showing no signs of osseous damage were evaluated. RUG angles were measured in four anatomically defined axial planes that spanned from the proximal to the distal end of the RUG. Furthermore, distance measurements at the medial epicondyle were conducted. A classification system for the RUG is proposed based on the acquired RUG angles, aiming to categorize the individual angles according to the 25th and 75th percentiles. RESULTS: RUG angles were significantly larger in males compared to females (p < 0.001) accompanied by larger distances including the off-set and height of the medial epicondyle (p < 0.001). RUG angles decreased from proximal to distal locations (p < 0.05). CONCLUSION: This study revealed that men exhibited larger RUG angles compared to women, indicating a less-concave shape of the RUG in men. Introducing an objective RUG classification system can improve our understanding of anatomical variations and potentially find application in diagnostics and preoperative planning.

Comparison of electrodiagnostic findings in acute traumatic versus chronic non-traumatic ulnar neuropathy at the elbow.

INTRODUCTION/AIMS: A common concept is that traumatic nerve injuries are more likely axonal, and that compressive neuropathies are more likely demyelinating. The purpose of this study was to compare traumatic versus non-traumatic ulnar neuropathy at the elbow (UNE) to look for electrodiagnostic differences between the two groups. METHODS: A retrospective 3 year review of UNE patients at two academic health science centers was conducted. Patients were grouped into acute traumatic UNE versus chronic non-traumatic UNE based on clinical history. Electrodiagnostic measurements were compared between the two groups. RESULTS: There were 50 subjects with acute traumatic UNE and 41 with chronic non-traumatic UNE. Mean age and sex distribution were similar but those with traumatic UNE had a 7 month duration of symptoms, while those with chronic UNE had 29 month duration (p < .001). All electrodiagnostic measurements were similar between the two groups including compound muscle action potential amplitudes, motor conduction velocities, frequency of conduction block, sensory nerve studies, and needle electromyography. DISCUSSION: We did not find a difference between the two groups. One should not make inferences regarding acuity or etiology based on electrodiagnostic features alone.

The Evolution of the Reconstructive Strategy for Elbow Flexion for Acute C5, C6 Brachial Plexus Injuries over Two Decades.

BACKGROUND: Over the course of the past two decades, improved outcomes following brachial plexus reconstruction have been attributed to newer nerve transfer techniques. However, key factors aside from surgical techniques have brought improved consistency to elbow flexion techniques in the latter decade. METHODS: One-hundred seventeen patients who underwent brachial plexus reconstruction from 1996 to 2006 were compared with 120 patients from 2007 to 2017. All patients were evaluated preoperatively and postoperatively to assess the recovery time and of elbow flexion strength. RESULTS: In the first decade, nerve reconstruction methods included proximal nerve grafting, intercostal nerve transfer, and Oberlin-I transfer. In the second decade, newer methods such as double fascicular transfer and ipsilateral C7 division transfer to the anterior division of upper trunk were introduced. About 78.6% of the first decade group versus 87.5% of the second decade group were able to reach M3 flexion strength (p = 0.04), with shorter time recovery to reach M3 in the 2nd decade. About 59.8% of the first decade group versus 65.0% of the second decade group were able to reach M4 (p = 0.28), but no significant difference in time of recovery. In both groups, the double fascicular nerve transfer had the highest impact when introduced in the second decade. More precise magnetic resonance imaging (MRI) techniques helped to diagnose the level of injury, the roots involved and evaluate the health of the donor nerves in preparation for intraplexus transfer. CONCLUSION: In addition to modified techniques in nerve transfers, (1) MRI-assisted evaluation and surgical exploration of the roots with (2) more judicious choice of donor nerves for primary nerve transfer were factors that ensured reliable and outcomes in the second decade.

The necessity of electrodiagnostic studies and ultrasound in ulnar nerve entrapment according to surgeons in the Netherlands.

BACKGROUND: Ulnar nerve entrapment at the elbow (UNE) is the second most prevalent entrapment neuropathy after carpal tunnel syndrome. The objective of this study was to evaluate the expert opinion of different surgical disciplines regarding the need for electrodiagnostic or ultrasound confirmation of UNE and, if so, which test was preferred for confirmation. METHODS: A questionnaire was sent to all neurosurgeons and plastic or hand surgeons in the Netherlands to evaluate the current practice in planning surgical treatment of UNE. RESULTS: The response rate was 36.4 % (134 out of 368). 94 % of surgeons reported that > 95 % of their patients had EDX or ultrasound studies before surgery. 80.6 % of all surgeons who responded reported that they seldom operated on UNE without electrodiagnostic confirmation. Hand surgeons (25.9 %) were more willing to operate on clinically diagnosed UNE without EDX than neurosurgeons (9.4 %) CONCLUSIONS: Dutch surgeons prefer diagnostic confirmation of UNE either by ultrasound or EDX, with a preference for EDX and the vast majority of operated patients do have either EDX or ultrasound or both before surgery. Compared to neurosurgeons, hand surgeons are more willing to operate on patients with clinically defined UNE but normal electrodiagnostic studies.

Axillary to Radial Nerve Transfer for Recovery of Elbow Extension After Spinal Cord Injury.

BACKGROUND AND OBJECTIVES: Cervical spinal cord injuries (SCI) result in severe loss of function and independence. Nerve transfers have become a powerful method for restoring upper extremity function, the most critical missing function desired by this patient population. Recovery of active elbow extension allows for expansion of one's workspace to reach for objects and stabilizes control at the elbow joint. Without triceps function, a patient with a cervical SCI is rendered entirely helpless when in the supine position. Our objective was to provide a concise description of the transfer of branches of the axillary nerve (AN) to the long head of the triceps branch of the radial nerve (RN) for restoration of elbow extension after cervical SCI. METHODS: An anterior, axillary approach is used for the transfer of the nerve branches of the AN (which may include branches to the teres minor, posterior deltoid, or even middle deltoid) to the long head of the triceps branch of the RN. Preoperative assessment and intraoperative stimulation are demonstrated to direct optimal selection of axillary branch donors. RESULTS: The axillary approach provides full access to all branches of the AN in optimal proximity to triceps branches of the RN and allows for tension-free coaptation to achieve successful recovery of elbow extension. Final outcomes may not be achieved for 18 months. Of our last 20 patients with greater than 12-month follow-up, 13 have achieved antigravity strength in elbow extension, 4 are demonstrating ongoing progression, and 3 are definitive failures by 18 months. CONCLUSION: The axillary to RN transfer is an important intervention for recovery of elbow extension after cervical SCI, which significantly improves quality of life in this patient population. Further large population outcomes studies are necessary to further establish efficacy and increase awareness of these procedures.

Management of Adult Traumatic Brachial Plexus Injury.

Brachial plexus injury is not uncommon in our country like Bangladesh and it causes functional damage and physical disability of the upper limbs. Most of the cases were caused by motor vehicle accident. We have conducted a prospective study for the operative treatment of 105 adult traumatic brachial plexus injury cases in Hand unit in the department of Orthopaedics, Bangabandhu Sheikh Mujib Medial University (BSMMU) during January 2012 to July 2019. The main surgical options for brachial plexus injury include primary reconstructive surgery such as neurolysis, direct repair, nerve graft, nerve transfer (neurotization) and possibly free functioning (gracilis) muscle transfer and secondary reconstructive procedure such as tendon transfer, arthrodesis, FFMT and bony procedure. Each of these procedures is used either alone or in combination for particular clinical scenarios. Aims and objectives of this study was to restoration of shoulder abduction and external rotation, elbow flexion and hand function are goal of treatment of adult traumatic brachial plexus injury. Age range was from 14 years to 55 years (mean age 26 years). Male were 95 and female were 10 cases. Time from trauma to surgery was valid 3 months to 9 months. Motor cycle accident was most common mechanism of injury. Upper plexus (C5, C6) injury was 52 cases, extended upper plexus (C5, C6 & C7) injury was 19 cases and global brachial plexus injury was 34 cases. When there is high suspicion of root avulsions, early exploration and reconstruction is indicated. Operate these patients 2-3 months after their injury. In other patients without high suspicion of root avulsion, we routinely perform exploration between 3 to 6 months after injury when no adequate sign of recovery are present. Common reconstructive options are any injury with neuroma in continuity with conductive nerve action potential (NAP): only neurolysis or any injury with nerve rupture or postganglionic neuroma not conducting nerve Action potential (NAP) and good proximal nerve: Direct repair or repair with nerve graft or nerve transfer if possible. Follow up period from 6 months to 6 years. The best results were obtained in C5, C6 and C5, C6 & C7 brachial plexus injury cases. SAN to SSN, Oberlin II and long head triceps motor branch to anterior division of axillary nerve transfer for C5 & C6 injury or upper plexus injury and in addition intercostals nerve to anterior division of axillary nerve and AIN branch of median nerve to ECRB for C5, C6 & C7 (extended upper plexus injury). Extra-plexus and intra-plexus neurotization was done in global brachial plexus injury cases and 5 cases by contra-lateral C7 to median nerve by vascularised ulnar nerve graft and only 2 cases contra-lateral C7 to lower trunk through pre spinal or pre tracheal route were done and only one case by FFMT. Few cases gain shoulder abduction and elbow flexion but no improvement of hand function and most cases even by FFMT still in follow up. Results of surgical treatment of upper and extended upper brachial plexus injury cases were satisfactory on the other hand recovery of shoulder abduction and elbow flexion was acceptable and comparable to other study in global brachial plexus injury and recovery of hand function were poor.

Anatomical variants complicating the posterior approaches towards the elbow joint.

INTRODUCTION: Anatomical variants observed during the posterior approach to the elbow joint require special attention due to their clinical relevance. We aim to present a compendious review of described variants potentially encountered during the posterior approach towards the elbow joint to the experts in the elbow surgery. METHODS: A narrative review of surgical and anatomical textbooks, as well as search of scientific databases was carried out. RESULTS: Variability of the subcutaneous nerves is important during incision planning. Accessory muscles such as dorsoepitrochlearis, chondroepitrochlearis, epitrochleoanconeus, subanconeus or supernumerary flexor carpi ulnaris may confuse even the senior surgeon during the dissection and possibly complicate the fracture reduction. Some bony variants such as supratrochlear foramen may lead to fracture or possibly interfere with the osteosynthesis placement. Accessory bones are also present in the region of the elbow joint. Those situated intra-articular may present with symptoms. CONCLUSION: Many variants can be encountered in the area of the elbow joint and their knowledge is essential to truly understand its anatomy. The presented review enables easier orientation in the current literature with the aim on the posterior approach towards the elbow joint.

Isolated medial antebrachial cutaneous nerve injury after blunt trauma: a case report.

BACKGROUND: The medial antebrachial cutaneous nerve is a branch of the brachial plexus that contains C8-T1 segments. Injury of this nerve by various mechanisms has been reported in the literature; however, currently, there is no reported case of medial antebrachial cutaneous nerve injury in the setting of acute blunt trauma. CASE PRESENTATION: This case report presents the case of a 34-year-old Persian female with dysesthesia and pain in the medial side of the forearm immediately following a blunt trauma by mechanism of elbow external rotation. On electrodiagnostic evaluation, the medial antebrachial cutaneous nerve sensory nerve action potential of the symptomatic side had a significant amplitude drop (more than 50%), compared with the other side. On follow-up electrodiagnosis, after several sessions of physical therapy, the medial antebrachial cutaneous nerve sensory nerve action potential still had a significant amplitude difference. CONCLUSION: Blunt trauma can be one of the causes of medial antebrachial cutaneous nerve involvement. An electrodiagnostic study can be helpful in the diagnosis of this nerve injury after blunt trauma.

Preoperative electrodiagnostic studies and postoperative outcomes for ulnar mononeuropathy at the elbow: A systematic review.

OBJECTIVE: To analyze the association between preoperative electrodiagnostic (EDX) studies and postoperative pain and functional outcomes following ulnar nerve decompression and/or transposition for ulnar neuropathy at the elbow (UNE). LITERATURE SURVEY: Protocol was submitted and database search was conducted by an experienced librarian of all available studies in the English language from 1990 to June 8, 2022. Databases included Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, and Scopus. METHODOLOGY: Inclusion criteria consisted of randomized controlled trials, prospective and retrospective longitudinal studies, and studies involving adults ≥18 years of age who underwent ulnar nerve decompression and/or transposition for UNE. Study quality and risk of bias were assessed using the National Heart, Lung, and Blood Institute (NHLBI) Study Quality of Assessment Tool. Certainty in evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. A meta-analysis was not performed. SYNTHESIS: A total of 289 studies were screened, and 8 retrospective cohort studies met inclusion criteria comprising 762 patients. A decreased or absent preoperative sensory nerve action potential amplitude (SNAP) showed significance with worse postoperative outcomes. The presence of preoperative conduction block showed significance in higher quality studies. There was limited evidence for slow preoperative motor conduction velocities or preoperative electromyography (EMG) abnormalities and postoperative outcomes. Overall quality assessment demonstrated that two studies had "good," four "fair," and two "poor" quality of evidence. Certainty in evidence was "low" due to risk of bias. CONCLUSIONS: A decreased or absent preoperative ulnar SNAP may predict worse postoperative outcomes. Per higher quality studies, preoperative conduction block at the elbow may also predict worse postoperative outcomes. Careful interpretation is required with a full understanding of the limited evidence, risk of bias, and low certainty in evidence to support the use of preoperative EDX to predict postoperative outcomes in UNE.

Long-term functional recovery in C5-C6 avulsions treated with distal nerve transfers.

BACKGROUND: In patients suffering from traction lesions of the brachial plexus, complete C5 and/or C6 root avulsion patients with C7 root preservation are relatively uncommon occurrences, but represent excellent candidates for surgical treatment, with satisfactory results. Shoulder abduction and extra-rotation, elbow flexion and forearm supination are lost functions restorable with surgical treatment. METHODS: This single-center, prospective observational study involved a series of 27 young adults with C5 and/or C6 root complete avulsion and C7 preservation, which underwent surgical repair with double or triple nerve transfer. RESULTS: Patients recovered a useful elbow flexion. Electromyographic and clinical signs of biceps reinnervation were observed in each UN-MC nerve transfer. The abduction strength recovery was M5 in 10 patients, M4 in 14 patients and M3 in 3 patients. The external rotation strength recovery was M5 in 4 patients, M4 in 18 patients, M3 in 3 patients and M2 in 2 patients. The elbow flection strength was M5 in 5 patients, M4 in 15 patients and M3 in 7 patients. Elbow extension was preserved in all cases. CONCLUSIONS: The concept of 'peripheral rewiring procedures' represents an advance in the repair of the peripheral nerve injuries. Triple nerve transfer can be nowadays considered a standard treatment for isolated C5-C6 avulsions. We report our experience with the second-biggest casuistry in the literature on patients treated with this technique. We consider our outcome concerning functional recovery to be satisfying and comparable to data reported in the literature.

Extensor digitorum muscle tendon to the index finger from the extensor carpi radialis brevis: a cadaveric case report.

The forearm extensor compartment is known for its wide variability in terms of muscle origin, number of tendons and their distal insertion. The index finger on its dorsal aspect is the typical place of insertion of the two tendons of the extensor digitorum (ED-index) and of the extensor indicis. Being acquainted with their anatomy is of immense importance to orthopaedic surgeons in the treatment of e.g., de Quervain's syndrome. The current report presents a rare finding of the ED-index tendon arising from the extensor carpi radialis brevis (ECRB). A routine dissection revealed their fused course from the lateral epicondyle of humerus, though separate from the extensor carpi radialis longus. The ED-index muscle belly separated from the ECRB, 119 mm distal to the lateral epicondyle. The distal insertion point of the ED-index was located radially to that of the extensor indicis. The deep branch of the radial nerve and the recurrent interosseous artery supplied the ED-index. No other musculotendinous variations were encountered neither on the ipsilateral nor the contralateral upper limb of the cadaver. This study presents in detail a tendon of the ED-index arising from the ECRB, a knowledge that can be applied namely in the lateral epicondylitis treatment or approach to the ulnar nerve at the level of the elbow. Extensive depiction of both the proximal and distal attachment points of the muscles, their course and dimensions is indispensable to attain the best patient outcomes and avoid iatrogenic injuries.

Long Head of Triceps Tendon Transfer for Agenesis of Biceps and Brachialis: Two Cases.

Congenital lack of elbow flexion results in significant disability and may be seen in conjunction with syndromes, plexopathies, neuromuscular disorders, or as an isolated muscular agenesis of elbow flexors. There are many tendon transfer options to address this issue, but there is a lack of data on the functional results in the pediatric population. In this series, we present 1 patient with isolated muscular agenesis of the biceps and brachialis musculotendinous units and another with this same muscular agenesis in the setting of arthrogryposis. They were treated with anterior ulnar nerve transposition and transfer of the long head of triceps tendon around 2 years of age resulting in functional elbow flexion in both patients.

The reanimation of the elbow functions in avulsive injuries of the upper brachial plexus using the medial cord transfer: nuances of the technique and update.

OBJECTIVES: Report on a new transfer for the reinnervation of biceps and brachialis muscles after multilevel avulsive injuries of brachial plexus provided at least T1 is viable: the Medial Cord to Musculocutaneous (MCMc) and its variant, the Medial Cord to anterior Upper Trunk (MC-aUT). The MC-aUT is indicated in agenesia of musculocutaneous nerve and when a residual function in the biceps is present. The MCMc transfer would be unfeasible in the former and contraindicated in the latter. METHODS: Three hundred and five consecutive patients, classified according to the quality of hand function, are available for a long-term follow-up after reconstructive surgery. They had multiple cervical root avulsive injuries at two (C5-C6), three (C5-C6-C7) and four (C5-C6-C7-C8) levels. The reinnervation was obtained via an end-to-end transfer from two donor fascicles located in the medial cord (MC) and aimed at the flexor carpi ulnaris or the flexor digitorum profundus. RESULTS: These transfers have no failures and no complications when the hand shows a normal function. In the case of suboptimal conditions of the hand, the technique is more challenging, but still has many satisfactory results. In the four-root avulsive injuries, on the contrary, strong limitations suggest that different strategies should be preferred. EMG shows a reinnervation in both biceps and brachialis muscles and this accounts for the quality of results. Tendon transfers for wrist and finger dorsiflexion, when required, remain unencumbered. DISCUSSION: The procedures are safe, effective and easily feasible. The ideal candidate has a C5-C6 injury and a normal hand function.

A Three months Electrodiagnostic Follow-Up of Patients Suspected of having Ulnar Nerve Involvement at Elbow Level with Normal Conventional Electrodiagnostic Study at First Evaluation.

Background: Compression of ulnar nerve at the elbow is the second most common peripheral neuropathy of the upper extremity. Objective: Due to the lack of the gold diagnostic standard for ulnar nerve involvement at elbow level (UNE) and the lack of sufficient study in this field, we decided to evaluate patients with symptoms of this disease who have normal conventional electrodiagnostic study (EDX) in first evaluation. Materials and Methods: In this cross-sectional study, 18 persons were selected from patients who were referred to the clinic of Physical Medicine and Rehabilitation. If conventional EDX was normal, compound nerve action potential (CNAP) test (peak latency and amplitude) was carried out. Patients with normal conventional EDX but abnormal ulnar CNAP included to our study. After 3 months, if they had not been treated for ulnar neuropathy, they were reexamined by conventional EDX plus ulnar CNAP measurement. Results: In total, 18 patients (11 females, 7 males) aged 28-58 years old (mean = 40.11) were analyzed in this study. After 3 months, 14 patients (77.8%) demonstrated parameter changes consistent with UNE in conventional EDX. Conclusion: Based on the results of this study, ulnar CNAP has diagnostic value in patients with symptoms of UNE who have normal routine EDX. Therefore, ulnar CNAP should be taken into account for early diagnosis of ulnar neuropathy when routine electrodiagnostic tests are normal.

A randomized trial to determine the minimum effective lidocaine volume for median nerve block using hydrodissection.

Ultrasound-guided hydrodissection with 5% dextrose in water (DW5) creates a peri-nervous compartment, separating the nerve from the neighboring anatomical structures. The aim of this randomized study was to determine the minimum volume of lidocaine 2% with epinephrine 1:200,000 required when using this technique to achieve an effective median nerve block at the elbow in 95% of patients (MEAV95). Fifty-two patients scheduled for elective hand surgery received an ultrasound-guided circumferential perineural injection of 4 ml DW5 and an injection of local anesthetic (LA) following a biased coin up-and-down sequential allocation method. A successful block was defined as a light touch completely suppressed on the two distal phalanges of the index finger within a 30-min evaluation period. The MEAV95 of lidocaine 2% with epinephrine was 4 ml [IQR 3.5-4.0]. Successful median nerve block was obtained in 38 cases (82.6%) with median onset time of 20.0 [10.0-21.2] minutes (95% CI 15-20). The analgesia duration was 248 [208-286] minutes (95% CI 222-276). Using an ultrasound-guided hydrodissection technique with DW5, the MEAV95 to block the median nerve at the elbow with 2% lidocaine with epinephrine was 4 ml [IQR 3.5-4.0]. This volume is close to that usually recommended in clinical practice.Trial registration clinicaltrials.gov. NCT02438657, Date of registration: May 8, 2015.

The ulnar nerve in the cubital tunnel: a foetal study.

BACKGROUND: The ulnar nerve (UN), a terminal branch of the medial cord of the brachial plexus, is located posteromedial to brachial artery coursing along medially in the arm from the anterior to the posterior compartment through the arcade of Struthers. It passes posterior to medial epicondyle of humerus and enters the cubital tunnel. Then, it exits through the distal part of the cubital fossa to enter the medial side of the forearm between the two heads of the flexor carpi ulnaris muscle underneath Osborne's ligament to enter the anterior compartment of the forearm. Entrapment of the UN at the cubital tunnel results in a pain and a tingling sensation on the medial side of the forearm and fourth and fifth digits. MATERIALS AND METHODS: This foetal study documented the course of the UN within the cubital tunnel and its anatomical relations utilising bilateral microscopic dissection of 25 foetuses (gestational age: 19-36 weeks). RESULTS: The UN followed the standard anatomical course in 96% (48/50) of the specimens, however it was found to lie deep to the muscles of the cubital tunnel in 6% (3/50). The radial artery joined the UN distal to the cubital tunnel in 8% (4/50), while the superior ulnar collateral artery was posteriorly related to the UN in 32% (16/50) of specimens. The Osborne's ligament (crossed between the two heads of the flexor carpi ulnaris muscle, posterior to the medial epicondyle of the humerus) was present in all specimens 100% (50/50). It had a mean length of 6.32 ± 0.97 mm and 6.30 ± 1.10 mm on the left and right sides, respectively. The current study observed that the flexor pronator aponeurosis was present in 2% (1/50) of specimens. CONCLUSIONS: Knowledge of the normal and variable anatomical course of the UN in the cubital tunnel in this study may assist in the diagnosis and treatment of compressive neuropathy of the UN in the cubital tunnel.

Risk factors of asymptomatic reduction of motor conduction velocity of the ulnar nerve across the elbow.

INTRODUCTION: The aim of the study was to check the risk factors for subjects with motor conduction velocity (MCV) reduction of the ulnar nerve across the elbow without symptoms/signs of ulnar neuropathy at the elbow (UNE) using a database of a previous multicenter case-control study on UNE patients. METHODS: From the previous database, we extracted all asymptomatic UNE (A-UNE) and matched for age and sex with a control and UNE groups with a ratio of 1:2. Anthropometric factors were measured and all participants filled in a questionnaire on demographic, lifestyle factors, and medical history. One-sample proportion test and univariate and multivariate logistic regression analyses were performed. RESULTS: We enrolled 64 A-UNE, 124 UNE, and 124 controls (mean age 53 years). There were more males with A-UNE than females (74.2%). The predominantly or exclusively concerned side of A-UNE was the right. Logistic regression showed that A-UNE was associated with diabetes (OR = 2.99, 95% CI = 1.21-7.39) and width of cubital groove (CGW) (OR = 0.89, 95%  CI = 0.81-0.97). DISCUSSION: Risk factors for A-UNE are different from UNE. The prevalence of right side in A-UNE was not due to particular elbow postures. Diabetes is a risk factor, probably because MCV reduction of the ulnar nerve across the elbow was an early manifestation of asymptomatic polyneuropathy in diabetes. A-UNE is associated with narrow CGW as already demonstrated in UNE, even if the OR was higher in UNE than in A-UNE. Only future longitudinal studies will be able to check whether the A-UNE subjects develop symptoms and signs of true mononeuropathy with time.

Evidence-based guideline: Neuromuscular ultrasound for the diagnosis of ulnar neuropathy at the elbow.

INTRODUCTION/AIMS: The purpose of this literature review is to develop an evidence-based guideline for the use of neuromuscular ultrasound in the diagnosis of ulnar neuropathy at the elbow (UNE). The proposed research question was: "In patients with suspected UNE, does ulnar nerve enlargement as measured with ultrasound accurately identify those patients with UNE?" METHODS: A systematic review and meta-analysis was performed, and studies were classified according to American Academy of Neurology criteria for rating articles for diagnostic accuracy. RESULTS: Based on Class I evidence in four studies, it is probable that neuromuscular ultrasound measurement of the ulnar nerve at the elbow, either of diameter or cross-sectional area (CSA), is accurate for the diagnosis of UNE. RECOMMENDATION: For patients with symptoms and signs suggestive of ulnar neuropathy, clinicians should offer ultrasonographic measurement of ulnar nerve cross-sectional area or diameter to confirm the diagnosis and localize the site of compression (Level B).