Ultrasound Diagnosis of Double Crush Syndrome of the Ulnar Nerve by the Anconeus Epitrochlearis and a Ganglion

Double compression of the ulnar nerve, including Guyon''s canal syndrome associated with cubital tunnel syndrome caused by the anconeus epitrochlearis muscle, is a very rare condition. We present a case of double crush syndrome of the ulnar nerve at the wrist and elbow in a 55-year-old man, as well as a brief review of the literature. Although electrodiagnostic findings were consistent with an ulnar nerve lesion only at the elbow, ultrasonography revealed a ganglion compressing the ulnar nerve at the hypothenar area and the anconeus epitrochlearis muscle lying in the cubital tunnel. Careful physical examination and ultrasound assessment of the elbow and wrist confirmed the clinical diagnosis prior to surgery.     

Ulnar neuropathy at the elbow due to unusual sleep position

Abnormal strain of the ulnar nerve over the sulcus due to an unusual sleep position is a rare cause of ulnar neuropathy at the elbow. A 57-year-old patient with Mandelung's deformity developed progressive weakness in the flexion of fingers 4 and 5 and in finger straddling on the left side. Additionally, there was slight wasting of the left hypothenar and the left interossei muscles. Motor and sensory nerve conduction studies of the left ulnar nerve showed delayed conduction velocities over the left ulnar sulcus. He preferred to sleep in a left lateral position with his head lying on a headrest roll, his left forearm being flexed at 110 degrees and his hand lying either under his cheek or placed on the roll. Only three weeks after the patient had been advised to change his sleep position and to sleep without the headrest roll, weakness markedly improved. This case shows that sleeping in a lateral position with the head on a headrest roll and the hand placed on the roll or under the cheek may cause ulnar neuropathy at the elbow. Change of such a habitual sleep position promptly resolves the symptoms.     

Martin–Gruber anastomosis with anomalous superficial radial innervation to ulnar dorsum of hand: A pitfall when common variants coexist

The Martin–Gruber anastomosis (MGA) is the most common anatomic variation in the upper extremity. Anomalous superficial radial innervation to the ulnar dorsum of the hand is the most common cause of an absent dorsal ulnar cutaneous (DUC) response. The coexistence of these variants introduces a relatively common yet underrecognized potential pitfall in nerve conduction studies (NCS). We performed confirmatory NCS in two cases referred for ulnar neuropathy in the forearm (case 1) and at the elbow (UNE, case 2). Initial NCS in both cases suggested ulnar nerve injury at the forearm and elbow, respectively, based on an apparent conduction block in ulnar motor fibers in the forearm (case 1) and elbow (case 2), and absent DUC responses. Additional NCS documented an MGA in the mid‐forearm (case 1) and high proximal forearm (case 2) with anomalous superficial radial innervation to the ulnar dorsum of the hand (both cases). Failure to recognize the coexistence of these two common variants may lead to misdiagnosis of ulnar neuropathy and inappropriate treatment. Muscle Nerve, 2009     

Peripheral nerve conduction in patients with a cervical rib and band

In 14 patients with wasting of the hand due to a cervical rib and band, motor and sensory conduction studies on the peripheral parts of the median and ulnar nerves were helpful in establishing the correct diagnosis. The median nerve findings excluded carpal tunnel syndrome even when the clinical pattern of wasting in the hand suggested this diagnosis. Preservation of conduction velocity in the ulnar nerve excluded ulnar entrapment at the elbow; the reduced amplitude of the ulnar sensory action potentials (SAPs) indicated that the lesion was distal to the dorsal root ganglia. In 3 patients with ulnar SAP amplitudes that were low but not clearly abnormal, the level of the lesion was confirmed by a reduced response to intradermal injection of histamine on the inner side of the forearm.     

Sequential nerve conduction studies in a patient with ulnar neuropathy at the elbow treated by night athletic supporter]

Ulnar nerve can be stretched with the elbow flexed position. To avoid elbow flexed position in patients with ulnar neuropathy at the elbow we used an athletic elbow supporter. We herein demonstrate a 31-year-old man with right ulnar neuropathy at the elbow whose neuropathy was resolved by using this supporter only at night. He had complained of weakness and paraesthesia in the ulnar side of his right hand. Nerve conduction studies of right ulnar nerve revealed decrease in the amplitude of compound nerve action potentials and a severe motor nerve conduction block with apparent conduction delay around the ulnar groove. A diagnosis of ulnar neuropathy at the elbow was done and we recommended him to wear an athletic elbow supporter at night. Paraesthesia of his right hand improved in a few days after starting this therapy. Three months later paraesthesia was resolved. One year later grip power of his right hand increased to 35 kg from 20 kg, and the conduction block at the elbow completely disappeared. Compound nerve action potentials, recorded at the segment of wrist to above elbow and wrist to finger, were improved equally. These observations suggest that the conduction block at the elbow entrapment site and the distal axonal degeneration gradually recovered together.     

Electrophysiological study of forearm sensory fiber crossover in Martin-Gruber anastomosis

Although anatomical studies have shown that a crossover of sensory fibers is not rare in forearm Martin-Gruber median-ulnar anastomosis (MGA), it has been electrophysiologically described only in rare subjects. Using a near-nerve needle technique, the possibility of electrophysiologically detecting a forearm median-ulnar crossover of sensory fibers was investigated in 24 arms of 21 subjects with unilateral or bilateral MGA, by stimulating the fifth digit of the hand and recording along the median nerve. Small-amplitude elbow responses were found in the median nerve in 10 of the 24 arms but, in 9, the responses disappeared after lidocaine block of the ulnar nerve distal to the elbow sulcus, indicating their volume-conducted origin. In one subject with carpal tunnel syndrome and a subclinical ulnar neuropathy at the elbow, the elbow response was not affected by the ulnar block, thus confirming the presence of a sensory anastomosis in the forearm. In another subject with MGA, a clear-cut sensory response was recorded in the median nerve at the elbow by stimulating the fifth digit of the right hand but no anesthetic block was performed, because ulnar responses were absent above the elbow sulcus due to a severe lesion at the elbow. Thus, use of a near-nerve recording technique facilitates recognition of median-ulnar crossover of sensory fibers to the fifth digit, which is, however, uncommon.     

Compression of the ulnar nerve at the elbow by an intraneural ganglion.

A rare cause of ulnar nerve compression at the elbow is presented in this report. A 42 year old right-handed mechanic developed subacute, progressive numbness, tingling and weakness in his right hand. Electrophysiologic studies demonstrated a severe conduction block affecting the ulnar nerve in the retrotrochlear groove but without any sign of major axonal loss. His hand functions were carefully studied prior to surgery. While fine motor tasks were not affected, the hand strength was markedly diminished. At surgery, a 1-cm diameter intraneural ganglion at the site of the conduction block was found and excised. The patient made a dramatic recovery within 6 weeks post-surgery. The conduction block completely resolved and the hand functions also returned to normal. This and other reported cases point to the importance of early diagnosis and intervention.     

Evaluation of patients with recurrent symptoms after ulnar nerve transposition

Focal entrapment of the ulnar nerve occurs most frequently in the region of the elbow, at the ulnar groove or beneath the humeroulnar aponeurosis. Surgical treatment commonly involves transposition of the nerve anterior to the medial epicondyle, in the antecubital fossa. Symptoms may recur after surgery, and, to assess their etiology, we studied 10 patients with recurrent ulnar symptoms after transposition. Conventional motor and sensory conduction studies were performed, as was mapping of nerve position using submaximal stimuli. In 9 of 10 patients, the ulnar nerve at the elbow was located adjacent to the medial epicondyle, rather than in the antecubital fossa. Focal slowing in the region of the elbow was noted in 8 patients, and an additional site of focal slowing was found in the forearm in 3 patients. We conclude that in patients with recurrent symptoms after ulnar nerve transposition postoperative position of the ulnar nerve may be medial, often near the medial epicondyle. This location may predispose the nerve to recurrent trauma or cause traction on the nerve at more distal locations within the forearm. The prevalence of this medial location of the ulnar nerve in asymptomatic postsurgical patients is unknown.     

A rare anterior spinal epidural cyst mimicking Hirayama disease

Introduction: Hirayama disease is a rare focal motor neuron disorder that manifests as slowly progressive unilateral or bilateral hand weakness and atrophy. Methods: The case report of a young man who presented with the phenotype of Hirayama disease indicated an extensive anterior cervical epidural arachnoid cyst. Results: A 34‐year‐old man presented with a 5‐year history of slowly progressive hand and forearm weakness and atrophy. Nerve conduction studies demonstrated low median and ulnar motor amplitudes, and EMG demonstrated fibrillation potentials and long‐duration, high‐amplitude motor unit potentials in C6–T4‐innervated muscles. MRI demonstrated a longitudinally extensive anterior spinal epidural cyst extending from C2 to L1. The patient had improved hand strength after surgery. Conclusions: Anterior cervical epidural spinal cysts should be considered in the differential diagnosis in patients who present with slowly progressive hand weakness. Muscle Nerve, 2012     

Collagen content in human ulnar nerve

Summary A quantitative analysis of ulnar nerve collagen in the arm and forearm was undertaken in nine subjects. While endoneurial collagen was found to be significantly increased within the cubital tunnel, extrafascicular collagen did not increase at the elbow except in two nerves showing fusiform enlargements. Renaut bodies increased in frequency at sites of high endoneurial collagen content. Morphological determinations of cross-sectional area along the ulnar nerve did not correlate with quantitative collagen data.     

Median--ulnar nerve communications and carpal tunnel syndrome.

Carpal tunnel syndrome in the presence of anomalous median to ulnar nerve communications in the forearm produces a characteristic change in motor conduction studies. Median nerve stimulation at the elbow evokes a thenar muscle action potential (MAP) with an initial positive deflection not seen on stimulation at the wrist. In 63 patients this change occurred in 16 (25%) and is a useful additional criterion in the diagnosis of carpal tunnel syndrome. The initial positive deflection is due to the volume-conducted MAP from the first dorsal interosseous and some thenar muscles whose motor point lies some distance from the recording electrode over abductor pollicis brevis. The first dorsal interosseous and thenar MAPs resulting from elbow stimulation of those median nerve axons crossing to ulnar nerve in forearm, are generated before that from thenar muscles supplied by the axons going through the carpal tunnel.     

Differentiation of ulnar neuropathy at the wrist due to ganglion cyst from ulnar neuropathy at the elbow

ObjectiveHere, we aimed to describe the clinical, electrodiagnostic (EDx) and ultrasonographic (US) findings in a series of patients with ulnar neuropathy at the wrist (UNW) due to compression by a ganglion cyst. We also sought features that differentiate UNW from ulnar neuropathy at the elbow (UNE).MethodsWe reviewed electronic medical records of consecutive patients with UNW caused by ganglion cysts. We compared their clinical, EDx and US findings to findings in our previously reported prospective series of UNE patients.ResultsWe identified 10 patients with UNW caused by ganglion cyst compression, who all presented with intrinsic hand muscle weakness and atrophy. Compared to 175 UNE patients they less often complained of paresthesia (60% vs. 98%) and presented less sensory loss in the palm (30% vs. 96%) and little finger (50% vs. 95%). They more often had distal ulnar motor latency recorded from the abductor digiti minimi (ADM) > 3.6 ms (80% vs. 30%), and denervation activity on needle EMG in the first dorsal interosseous (FDI) compared to ADM (100% vs. 60%). Only 20% of our UNW patients had ulnar nerve swelling at the site of compression on US.ConclusionUNW potentially caused by ganglion cyst should be suspected in patients presenting with intrinsic hand muscle atrophy and weakness, particularly in cases with normal sensation, increased distal ulnar motor latency recorded from ADM and more severe neuropathic changes in FDI compared to ADM muscle.     

New near-nerve needle nerve conduction technique: differentiating epicondylar from cubital tunnel ulnar neuropathy.

At the elbow, the ulnar nerve is compressed most commonly either in the epicondylar groove or at the cubital tunnel. While conventional electrodiagnosis may localize an ulnar neuropathy to the elbow, separating epicondylar syndrome (tardy ulnar nerve palsy) from cubital tunnel syndrome is more difficult. We describe a new method using a near-nerve needle technique for distinguishing these two types of ulnar neuropathy at the elbow. We placed three active needle electrodes across the elbow: the first was 4 cm above, and the second and third were 1.5 cm and 6 cm below the medial epicondyle, respectively. The latter two points were chosen because of the presence of the cubital tunnel in this segment. Sensory, motor, and mixed nerve conduction studies (NCS) were performed on these two segments (elbow segment and cubital tunnel segment) in 26 normal nerves and normal data were established. We also present 7 cases of epicondylar ulnar nerve palsy and 1 case of cubital tunnel syndrome in which we were able to confirm the diagnosis with the present method. In 3 cases of epicondylar ulnar nerve palsy, the present method accurately localized the lesion when other methods failed. We believe that this method will be helpful in distinguishing cubital tunnel syndrome from epicondylar ulnar nerve palsy, especially in early ulnar neuropathy in which only sensory fibers are involved.     

Transient forearm conduction block in the median nerve

We present two cases referred for electrophysiological confirmation of carpal tunnel syndrome (CTS). Initial nerve conduction studies were normal. Approximately 20 min into the examination, both patients developed sensory symptoms and weakness in the distal median nerve territory while the elbow was extended and forearm supinated. Further studies demonstrated complete conduction block across the forearm in the median motor and sensory nerve fibers. When measurable, conduction velocities remained normal or were modestly slow. Complete clinical and electrophysiological recovery occurred within 2 min following forearm pronation, suggesting that dysfunction was probably due to focal transient ischemia. Patients describing increased sensory symptoms during routine electrophysiological assessments for CTS should be investigated to rule out the possibility of a more proximal abnormality.     

Effect of body mass index on ulnar nerve conduction velocity, ulnar neuropathy at the elbow, and carpal tunnel syndrome

Both high and low body mass index (BMI) have been reported as risk factors for ulnar neuropathy at the elbow (UNE), and a high BMI as a risk factor for carpal tunnel syndrome (CTS). To determine whether the extremes of BMI are risk factors for UNE or CTS, and whether BMI affects calculation of median and ulnar motor nerve conduction velocity (NCV), we retrospectively analyzed the electrodiagnostic records of control patients, UNE patients, and CTS patients. The BMI was calculated for 50 patients with a sole diagnosis of UNE and compared to the BMI of 50 patients with CTS and 50 control subjects. The mean BMIs were 25.9 +/- 4.4, 30.1 +/- 5.5, and 28.3 +/- 5.6 for the UNE, CTS, and controls, respectively. By one-way analysis of variance, the difference in BMI between the UNE patients and the normal patients was significant (P < 0.01). In the control groups, increasing BMI directly correlated with increasing ulnar motor NCV across the elbow but not with forearm NCV. Across-elbow (AE) ulnar motor NCV may be falsely increased in patients with a high BMI, probably due to distance measurement factors. Not only do relatively slender individuals have comparatively slower AE ulnar NCVs, they are also at increased risk for developing UNE. Patients with a high BMI are at increased risk for CTS.     

Changes in nerve conduction velocity across the elbow due to experimental error

One diagnostic criterion for ulnar nerve mononeuropathy at the elbow (UNE) is a decrease in across-elbow nerve conduction velocity (NCV) > 10 m/s compared to the forearm segment. Distance and latency measurement errors are an inherent part of NCV calculations. Twenty electromyographers measured the latencies of stored ulnar compound muscle action potentials and measured the forearm and across-elbow distances along the ulnar nerve. Based on previously published equations, experimental error in NCV was calculated for various NCVs. The mean distances and standard deviations for the forearm and elbow segments were 212.5 +/- 2.1 mm and 86.7 +/- 4.2 mm, respectively. For an NCV of 55 m/s, a difference of 14 m/s between the two segments can occur from measurement error alone. Distance measurements about the elbow are fraught with interobserver errors rendering the resultant NCV of that segment of limited value as a sole criterion for the diagnosis of UNE.     

Applied anatomical study of the vascularized ulnar nerve and its blood supply for cubital tunnel syndrome at the elbow region

Cubital tunnel syndrome is often accompanied by paresthesia in ulnar nerve sites and hand muscle atrophy. When muscle weakness occurs, or after failure of more conservative treatments, anterior transposition is used. In the present study, the ulnar nerve and its blood vessels were examined in the elbows of 18 adult cadavers, and the external diameter of the nutrient vessels of the ulnar nerve at the point of origin, the distances between the origin of the vessels and the medial epicondyle of the humerus, and the length of the vessels accompanying the ulnar nerve in the superior ulnar collateral artery, the inferior ulnar collateral artery, and the posterior ulnar recurrent artery were measured. Anterior transposition of the vascularized ulnar nerve was performed to treat cubital tunnel syndrome. The most appropriate distance that the vascularized ulnar nerve can be moved to the subcutaneous tissue under tension-free conditions was 1.8 ± 0.6 cm(1.1–2.5 cm), which can be used as a reference value during the treatment of cubital tunnel syndrome with anterior transposition of the vascularized ulnar nerve.     

Variations in anatomy of the ulnar nerve at the cubital tunnel: pitfalls in the diagnosis of ulnar neuropathy at the elbow.

Two processes account for most instances of ulnar neuropathy at the elbow: compression in the retroepicondylar groove, and compression by the humeroulnar aponeurotic arcade joining the two heads of the flexor carpi ulnaris. While conventional electrodiagnostic criteria may localize an ulnar neuropathy to the elbow, separating retroepicondylar compression from humeroulnar arcade compression is more difficult. In 130 cadaver elbows, we examined the relationships between the medial epicondyle, flexor carpi ulnaris, and ulnar nerve. The humeroulnar arcade lay from 3 to 20 mm distal to the medial epicondyle, the intramuscular course of the nerve through the flexor carpi ulnaris ranged from 18 to 70 mm, and the nerve exited the flexor carpi ulnaris 28 to 69 mm distal to the medial epicondyle. In 6 specimens, dense fibrous bands bridged directly between the medial epicondyle and the olecranon proximal to the cubital tunnel proper; accessory epitrochleoanconeus muscles were present in 14 specimens: both may cause ulnar neuropathy at the elbow. Anatomical variations may contribute to the difficulty in separating causes of ulnar neuropathy at the elbow.     

Relations between sensory symptoms,touch sensation,and sensory neurography in the assessment of the ulnar neuropathy at the elbow

ObjectivesTo evaluate sensitivity, specificity and predictive values of sensory findings in ulnar neuropathy at the elbow (UNE), differences according to UNE localization and pathophysiology, and relation between the sites of sensory symptoms, abnormal evaluation of sensation and neurographic findings of ulnar sensory nerve.MethodsHand diagram and Semmes-Weinstein monofilaments were used for clinical evaluation in four ulnar hand territories. Sensory neurography was measured in the fourth and fifth digits-wrist segments (U5) and in the dorsal ulnar cutaneous nerve.ResultsWe enrolled 75 idiopathic UNE cases and 180 controls. Symptoms in the fifth digit, reduction of touch sensation and U5 sensory nerve action potential amplitude (SNAPa) had the highest sensitivity, specificity and predictivity in UNE diagnosis. The normal/abnormal sensory clinical findings of the fifth digit matched with normal/abnormal U5 SNAP more than the matching of sensory parameters in the other ulnar hand sites. Sensory anomalies were more frequent in predominantly axonal than demyelinating UNE. There were no differences according to UNE location.ConclusionSensory anomalies of the fifth digit are constant findings in UNE more than anomalies of the other ulnar nerve hand regions.SignificanceProbably the fascicles from fifth digit are the most liable to damage at elbow.     

尺神经前置动物模型的建立及其神经生化研究

目的 建立尺神经前置的动物模型并从分子水平上评价尺神经前置的安全性.方法 取健康成年SD大鼠20只,建立右前肢尺神经前置模型,左侧(非手术侧)作为自身对照,术后1个月处死大鼠,取双侧尺侧腕屈肌称重及下颈段脊髓(C_6～T_1)切片,通过Nissl染色、还原型辅酶Ⅱ-黄递酶(NADPH-d)组织化学染色、植物凝集素(IB4)染色、胆碱乙酰基转移酶(CHAT)免疫组织化学染色观察颈髓前角、后角神经元的形态,电镜观察颈髓前角ChAT免疫阳性运动神经元的超微结构.结果 与对照侧[(93.2±7.29)mg]比较,大鼠尺神经前置侧尺侧腕屈肌质量[(92.3±9.13)mg]无明显变化,差异无统计学意义(t=0.910,P=0.378);Niss1染色、NADPH-d、IB4、ChAT免疫组织化学染色结果均显示大鼠尺神经前置侧和对照侧相比较细胞形态无明显改变,阳性细胞数量差异均无统计学意义(P>0.05);电镜结果显示颈髓前角ChAT免疫阳性运动神经元的超微结构无明显改变.结论 动物实验基础上尺神经前置术是安全的.