Ulnar nerve compression in Guyon's canal due to a haemangioma of the ulnar artery

Ultrasonography in Distal Ulnar Nerve Neuropathy: Findings in 33 Patients

PURPOSE

Although there are many case reports on the role of ultrasonography (US) in distal ulnar nerve neuropathy (Guyon canal syndrome), there is a paucity of large series in the literature because of its rarity. During an 8-year period, 33 instances of electrodiagnostically confirmed cases underwent US imaging. These cases were analyzed to determine the role of US in uncovering the cause of distal ulnar nerve neuropathy and its contribution to further management.

METHODS

This was a retrospective study of patients diagnosed with distal ulnar nerve neuropathy based on electrodiagnostic criteria, who also had undergone US (measurement of the cross-sectional area and documentation of causes such as cysts and neuromas).

RESULTS

US showed normal ulnar nerve in 5, cysts in 10, neuromas in 2, and nonspecific enlargement in 16 patients. Surgery was performed in 15 patients, and the US findings were corroborated in those with cysts and neuromas; 1 patient had an aberrant muscle, and two had fibrous bands constricting the ulnar nerve in the Guyon canal (not detected preoperatively by US imaging).

CONCLUSIONS

US imaging detected the underlying cause of distal ulnar nerve neuropathy in a significant percentage of patients, potentially contributing to effective treatment.

Isolated Compression of the Ulnar Nerve Motor Branch: A Case Series With 3 Unique Etiologies

BACKGROUND

Although ulnar neuropathies are commonly encountered, isolated involvement of the motor branch is exceedingly rare. Previous reports of this entity describe compression as the deep motor branch passes through the piso-hamate hiatus and the adductor pollicis hiatus. This case series described 3 cases of motor branch compression due to unique etiologies which resolved after surgery.

METHODS

A retrospective chart review identified patients with compression of the ulnar nerve motor branch. From these patients, 3 were selected with a unique etiology for compression. Patient demographics, objective and subjective findings, and pathology identified during surgery were recorded and analyzed.

RESULTS

Eight patients had compression of the ulnar nerve motor branch and 3 unique etiologies were selected; an intraneural ganglion, a constricting leash of vessels, and a series of compressing fibrous bands. All required surgery, and each patient had full resolution of symptoms by 1 year postoperatively.

DISCUSSION

Patients presenting with complaints of weakness with a positive Froment and Egawa signs but a negative Wartenberg sign and no sensory complaints can be a diagnostic dilemma. Compression of the ulnar nerve motor branch must be considered, and here we present 3 unique cases. Activity modification in those presenting early may be curative, although many ultimately require surgery. In the cases presented here, all patients experienced full resolution of their symptoms by 1 year after surgery.

Ulnar tunnel syndrome

Ulnar neuropathy at or distal to the wrist, the so-called ulnar tunnel syndrome, is an uncommon but well-described condition. However, diagnosis of ulnar tunnel syndrome can be difficult. Paresthesias may be nonspecific or related to coexisting pathologies, such as carpal tunnel syndrome, cubital tunnel syndrome, thoracic outlet syndrome, C8-T1 radiculopathy, or peripheral neuropathy, which makes accurate diagnosis challenging. The advances in electrodiagnosis, ultrasonography, computed tomography, and magnetic resonance imaging have improved the diagnostic accuracy. This article offers an updated view of ulnar tunnel syndrome as well as its etiologies, diagnoses, and treatments.

Uncommon upper extremity compression neuropathies

Hand surgeons routinely treat carpal and cubital tunnel syndromes, which are the most common upper extremity nerve compression syndromes. However, more infrequent nerve compression syndromes of the upper extremity may be encountered. Because they are unusual, the diagnosis of these nerve compression syndromes is often missed or delayed. This article reviews the causes, proposed treatments, and surgical outcomes for syndromes involving compression of the posterior interosseous nerve, the superficial branch of the radial nerve, the ulnar nerve at the wrist, and the median nerve proximal to the wrist.

Ulnar tunnel syndrome

Ulnar tunnel syndrome could be broadly defined as a compressive neuropathy of the ulnar nerve at the level of the wrist. The ulnar tunnel, or Guyon's canal, has a complex and variable anatomy. Various factors may precipitate the onset of ulnar tunnel syndrome. Patient presentation depends on the anatomic zone of ulnar nerve compression: zone I compression, motor and sensory signs and symptoms; zone II compression, isolated motor deficits; and zone III compression; purely sensory deficits. Conservative treatment such as activity modification may be helpful, but often, surgical exploration of the ulnar tunnel with subsequent ulnar nerve decompression is indicated.

Guyon's canal syndrome: a rare case of venous malformation

This paper describes an unusual case of parasthesia in the medial two fingers of the hand in a 56-yearold lady. MRI suggested a space occupying lesion and on exploration this proved to be a venous malformation causing a pressure neuropathy of the ulnar nerve.

Ulnar Nerve Compression at Guyon's Canal by an Arteriovenous Malformation

Guyon's canal at the wrist is not the common site of ulnar nerve compression. Ganglion, lipoma, anomalous tendon and muscles, trauma related to an occupation, arthritis, and carpal bone fracture can cause ulnar nerve compression at the wrist. However, ulnar nerve compression at Guyon's canal by vascular lesion is rare. Ulnar artery aneurysm, tortous ulnar artery, hemangioma, and thrombosis have been reported in the literature as vascular lesions. The authors experienced a case of ulnar nerve compression at Guyon's canal by an arteriovenous malformation (AVM) and the patient's symptom was improved after surgical resection. We can not easily predict vascular lesion as a cause of ulnar nerve compression at Guyon's canal. However, if there is not obvious etiology, we should consider vascular lesion as another possible etiology.

Vascular leiomyoma resulting in ulnar neuropathy: case report

We report a case of vascular leiomyoma arising from the distal ulnar artery in the palm that revealed symptoms similar to those of Guyon's canal syndrome.

Median nerve compression caused by a venous aneurysm. Case report

A rare case of peripheral-nerve compression in the upper arm caused by a spontaneous venous aneurysm is reported. The apparent dysfunction of the median nerve led to various vain surgical explorations of the nerve at different levels. The real localization of nerve entrapment was identified by a thorough clinical examination, and sonography yielded a correct diagnosis. Surgical resection of the venous aneurysm resulted in complete relief of pain. To the authors' knowledge, this is the first report of a spontaneous venous malformation in the upper arm causing focal neuropathy.