Compressive neuropathies of the ulnar nerve at the elbow and wrist.
Compressive neuropathy of the ulnar nerve in the upper limb is a common problem that frequently results in severe disabilities. At the elbow, Lundborg concluded that the nerve was "asking for trouble" because of its anatomic course through confined spaces and posterior to the axis of elbow flexion. Normally, the ulnar nerve is subjected to stretch and compression forces that are moderated by its ability to glide in its anatomic path around the elbow. When normal excursion is restricted, irritation ensues. This results in a cycle of perineural scarring, further loss of excursion, and progressive nerve damage. Initial treatment for the acute and subacute neuropathy at the elbow is nonsurgical. Rest and avoiding pressure on the nerve may suffice, but if symptoms persist, splint immobilization of the elbow and wrist is warranted. For chronic neuropathy associated with muscle weakness, or neuropathy that does not respond to conservative measures, surgery is usually necessary. A variety of surgical procedures have been described in the medical literature, and deciding on the most effective procedure can be difficult considering the excellent results claimed by proponents for each. Unfortunately, there is a paucity of information based on prospective randomized clinical studies comparing the different surgical methods. Dellon attempted to provide some guidelines by reviewing the data in 50 articles dealing with nonsurgical and surgical treatment of ulnar neuropathies at the elbow. In order to provide uniform data, he re-interpreted the data in these articles using his own system for staging nerve compression. He reported that treatment was most successful for mild neuropathies, a conclusion few would challenge. Excellent results were also achieved in 50% of patients with mild neuropathies that were treated nonsurgically and in more than 90% treated by surgery, regardless of the procedure. For moderate neuropathies, nonsurgical treatment was generally unsuccessful, as were decompressions in situ. Medial epicondylectomies were effective in only 50% of cases and they had the highest recurrence rate. Regarding ulnar nerve transpositions, each method has its proponents, usually based on the training and experience of the surgeon. Subcutaneous transposition is the least complicated. It is an effective procedure, particularly in the elderly and in patients who have a thick layer of adipose tissue in their arms. It is the procedure of choice for repositioning the nerve during surgical reductions of acute fractures, arthroplasties of the elbow, and secondary neurorrhaphies. Intramuscular and submuscular transpositions are more complicated procedures. Although proponents of intramuscular transposition report favorable results, the procedure can result in severe postoperative perineural scarring. Submuscular transposition has a high degree of success and is generally accepted to be the preferred procedure when prior surgery has been unsuccessful. I also prefer it as the primary procedure for most chronic neuropathies that require surgery. Compressive neuropathies of the ulnar nerve in the canal of Guyon are less common, but they can also result in significant disabilities. Compression can occur in 1 of 3 zones. Zone 1 is in the most proximal portion of the canal, where the nerve is a single structure consisting of motor and sensory fascicles, and zones 2 and 3 are distal where the ulnar nerve has divided into motor and sensory branches. The clinical picture correlates with the zone in which compression occurs.
Posner
M A
MA
New York University School of Medicine, USA.
D020430:Cubital Tunnel Syndrome / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D019299:Decompression, Surgical; D006801:Humans; D008866:Microsurgery; D009408:Nerve Compression Syndromes / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D020424:Ulnar Neuropathies / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D014953:Wrist / Q000294:innervation*