Ulnar nerve entrapment neuropathy in the forearm

Ulnar neuropathy

Ulnar neuropathy at the elbow is the second most common compressive neuropathy. Less common, although similarly disabling, are ulnar neuropathies above the elbow, at the forearm, and the wrist, which can present with different combinations of intrinsic hand muscle weakness and sensory loss. Electrodiagnostic studies are moderately sensitive in diagnosing ulnar neuropathy, although their ability to localize the site of nerve injury is often limited. Nerve imaging with ultrasound can provide greater localization of ulnar injury and identification of specific anatomical pathology causing nerve entrapment. Specifically, imaging can now reliably distinguish ulnar nerve entrapment under the humero-ulnar arcade (cubital tunnel) from nerve injury at the retro-epicondylar groove. Both these pathologies have historically been diagnosed as either "ulnar neuropathy at the elbow," which is non-specific, or "cubital tunnel syndrome," which is often erroneous. Natural history studies are few and limited, although many cases of mild-moderate ulnar neuropathy at the elbow appear to remit spontaneously. Conservative management, perineural steroid injections, and surgical release have all been studied in treating ulnar neuropathy at the elbow. Despite this, questions remain about the most appropriate management for many patients, which is reflected in the absence of management guidelines.

Possible points of compression of the ulnar nerve: Tricks and traps that await clinicians from an anatomical point of view

The ulnar nerve can be subject to numerous types of compression. The most common are cubital tunnel and ulnar tunnel syndromes, but there are many others with more uncommon etiologies. The existence of additional communicating branches, median nerve involvement, various types of injuries, and unusual anatomical variations can be a challenge for both diagnosis and treatment. This review presents a comprehensive depiction of ulnar nerve entrapment syndromes with particular reference to their anatomical background, risk factors, and clinical evaluation. Even common disorders can result from atypical morphological changes. It is important to be familiar with them as it is a key ability in daily medical practice.

Ulnar neuropathy in the forearm: A possible complication of diabetes mellitus

Ulnar neuropathy in the forearm is an unusual cause of hand weakness and sensory loss that is most often attributed to compression of the nerve distally within the humero-ulnar arcade (cubital tunnel). An association with diabetes mellitus, however, has not been reported. We identified four patients with type I diabetes mellitus and clinical findings suggestive of ulnar neuropathy in whom electrophysiologic testing revealed partial conduction block or abnormal temporal dispersion within the forearm segment of the ulnar nerve. Although evidence for a mild underlying polyneuropathy was present in three patients, the ulnar nerve abnormalities were disproportionately severe. In all cases, a Martin-Grüber anastomosis was excluded. Whether this lesion is due to an increased propensity to focal compression of the ulnar nerve within the humero-ulnar arcade or whether it represents a localized manifestation of the generalized polyneuropathy remains to be determined.

Tortuous peripheral arteries: a cause of focal neuropathy. Case report

Segmental ulnar neuropathy has been reported as a result of ulnar nerve compression due to posttraumatic false aneurysms of the ulnar artery and, more infrequently, due to thrombosis or true aneurysms of the same vessel. The authors present a case of segmental sensory ulnar neuropathy in the wrist which intraoperatively demonstrated impingement on the ulnar nerve by a tortuous ulnar artery. The symptomatic relief and electrophysiological improvement that occurred immediately following neurovascular decompression confirm that the vascular anomaly was the cause of neuropathy. Pulsatile pressure applied to the nerve trunk may have triggered ectopic stimulation of sensory fibers manifested by a tingling and burning sensation. There was immediate resolution of paresthesia following mobilization of the impinging vessel from the nerve. Subsequent rapid electrophysiological recovery may be explained by improvement in focal nerve microcirculation following vascular decompression. Tortuosity (megadolichoectatic anomaly) of intracranial arteries has been related to cranial nerve or brain-stem dysfunction; however, this appears to be the first report in the literature of a case in which such association has been found to occur extracranially, involving a peripheral nerve.

Spontaneous bilateral median nerve compressions in the distal arm

A case of bilateral median nerve compressions in the distal arm is described. The patient was seen initially with the spontaneous onset of paresis of the anterior interosseous nerve innervated muscles, as well as more proximal median nerve innervated muscles. There was no shoulder-girdle weakness or sensory abnormality. No systemic symptoms were identified. Surgical exploration in each extremity revealed enlarged communicating veins directly compressing the median nerve in the distal arms. Clinical improvement began 6 months after operation and was complete by 18 months.

AAEE case report #18: Ulnar neuropathy in the distal forearm

A 66-year-old professional golf instructor developed pain, numbness, and weakness in an ulnar distribution, but the lesion could not be localized to either elbow or wrist by routine nerve conduction techniques. Stimulation along serial 1-cm increments in the distal forearm disclosed a point of focal conduction block approximately 7 cm proximal to the ulnar styloid. At surgery, the flexor carpi ulnaris was enlarged, with muscle fibers extending all along the normally tendinous distal portion. A dense fibrovascular band coursed from the ulnar artery to the abnormal muscle, compressing the adjacent ulnar nerve. Intraoperative electroneurography precisely localized the area of conduction abnormality and helped identify the band as the compressing structure. Within 2 months following surgical decompression there was complete resolution of conduction block with excellent clinical recovery.

Ulnar neuropathy at the wrist associated with aberrant flexor carpi ulnaris insertion

A 36-year-old man who sustained an industrial hyperextension injury of the wrist complained of dysesthesia and pain in the ulnar nerve distribution, aggravated for months by wrist movement until exploration. The operation revealed an anomalous insertion of the flexor carpi ulnaris tendon disrupting a major portion of the ulnar nerve proximal to the pisiform. the symptoms were relieved completely after neurolysis and modification of the insertion of the tendon.

Median nerve neuralgia caused by a fibrovascular band in the distal forearm

A 67-year-old woman had experienced exquisite focal pain and tenderness for more than 1 year in the distal forearm 4.5 cm proximal to the distal wrist crease. Surgical exploration showed a venous fibrovascular band adherent to and transversing the epineurium of the median nerve precisely at the point of maximal tenderness. Resection of the fibrovascular band completely relieved the symptoms of focal pain and tenderness.

Anatomical basis for a technique of ulnar nerve transposition

There are five major anatomical locations where the ulnar nerve may be compressed near the elbow. Multiple sites of compression are often noted clinically; in other cases, the site of compression is difficult to identify. Clinical experience and results of a series of 20 anatomical dissections suggest that local decompression or subcutaneous transfer may be performed without necessarily exposing all five locations, posing a risk of incomplete decompression. Submuscular transfer of the ulnar nerve decompresses all five locations simultaneously and thus theoretically may be more reliable. The potentially superior results predicted by this anatomical investigation have been confirmed in a clinical case review. Submuscular transposition of the ulnar nerve is reliable and safe, not only in the primary treatment of ulnar neuropathy at the elbow but also in revision of previous operations.