Pigmented Villo Nodular Synovitis as an Atypical Cause of Deep Motor Branch Neuropathy

Introduction: Compression of the ulnar nerve in Guyon’s canal results in ulnar tunnel syndrome (UTS). The patient may present with sensory and motor deficits (zone 1), motor deficit (zone 2), or sensory deficit (zone 3). The most common causes of UTS include ganglion cysts, idiopathic ulnar nerve compression, occupational pressure neuritis (repetitive compression), prolonged compression, hook of hamate fractures, and arterial thrombus or aneurysm. Case Report: We report an atypical cause of UTS involving pigmented villonodular synovitis (PVNS) with a review of the literature. Surgical decompression of the ulnar nerve at Guyon’s canal has resulted in resolving motor weakness and improved interosseous strength at latest follow-up. Conclusion: The most common causes of UTS are ganglion, occupational neuritis, prolonged compression, and ulnar artery thrombi/aneurysms. However, other more rare causes such as PVNS should be considered in the appropriate patient. Keywords: Neuropathy, ulnar nerve, ulnar tunnel.

An unusual presentation of low ulnar nerve palsy: a case report

<p>Ulnar nerve compression at the Guyon’s canal is an uncommon cause of ulnar nerve neuropathy. Among various reasons like trauma, non-union of hook of hamate, anomalous muscle anatomy, thrombosis of the ulnar artery or pseudoaneurysm, ganglion is a common lesion which can compress the ulnar nerve at this site. With proper history taking and physical examination consisting of assessing motor functions and sensation of the hand, a clinician can localize the site of the lesion. Ultrasound is cheap and non-invasive technique which helps to localize the site of lesion and can suggest the nature of the lesion. Surgical decompression of the canal and careful removal of the lesion can help ameliorate the symptoms. In our study the patient presented with sudden onset weakness of the right hand and symptoms progressing within one and half month. With proper muscle charting, sensory examination and with the help of sonography, the main culprit was localized to Guyon’s canal. Excision of the lesion helped in recovery of hand function within 5 months.</p>