Feasibility and limitations of endoscopy in Guyon's canal.

This retrospective report summarizes observations from eight operations where the endoscopically assisted approach was used to explore Guyon's canal syndromes of idiopathic aetiology.

To evaluate the feasibility and limitations of endoscopic Guyon's canal release performed from a distal forearm incision.

Eight charts and video records of eight ulnar tunnel syndrome patients presenting concomitant idiopathic Guyon's canal syndromes were retrospectively reviewed. In all cases endoscopically assisted explorations in Guyon's canals with simultaneous cubital tunnel releases were performed.

In all of the patients the multiple tight bands of the superficial volar carpal ligament forming the canal roof were divided. Some of these bands crossing the nerve in its direct vicinity could have been responsible for the constriction. We were also able to divide the proximal segment of the canal floor. We have observed, however, that the proximal to distal endoscopic dissection jeopardizes the motor branch of the ulnar nerve; therefore, it should not be used to release the pisohamate ligament, or the hypothenar fascia.

Although all of the patients showed improvement, we cannot recommend this method in its current form. We are of the opinion that safe endoscopic Guyon's canal operations may require a different approach.