27 Endoscopic Ulnar Nerve Decompression
Endoscopic cubital tunnel release is a minimally invasive procedure that relieves the compression on the ulnar nerve as it passes through the cubital tunnel. When conservative treatment fails, this procedure is used to relieve the pressure on the ulnar nerve.
Cubital tunnel syndrome (CuTS) is a compressive neuropathy of the ulnar nerve at the elbow. It has an estimated incidence of 18 to 25 per 100,000 person-years 1 and is the second most common form of nerve entrapment after carpal tunnel syndrome.
Anterior transposition of the ulnar nerve (ATUN) was once the accepted gold standard surgical procedure for idiopathic CuTS; however, more recently, simple decompression has steadily gained support. 2
The minimal differences in outcomes, higher-complication rates for ATUN, 3 and cost effectiveness analyses 4 suggest that simple decompression is a favorable surgical procedure for CuTS.
Endoscopic cubital tunnel release (ECuTR), the newest surgical option for simple ulnar nerve decompression at the elbow, has been described using a variety of techniques. 5
ECuTR, first described by Tsai et al in 1995, is a minimally invasive procedure that utilizes an endoscope for visualization through a small incision. 6 It entails a reduced soft-tissue dissection compared with traditional approaches so it potentially allows for a more rapid recovery with minimal scarring.
Although ECuTR is minimally invasive and thus should allow faster return to work time, a great number of studies to support this hypothesis are not still available. However patients who underwent ECuTR seemed to have lower complication and higher satisfaction compared with the open ulnar decompression group. 7
The aim of the ECuTR procedure is to relieve the pressure on the ulnar nerve doing a complete release of the compressive structures in the cubital tunnel.
Within the cubital tunnel, the ulnar nerve may be compressed at two different locations.
The first site is within the sulcus on the posterior surface of the medial humeral epicondyle (the sulci nervi ulnaris). The arcuate ligament of Osborne creates a fibro-osseous tunnel, spanning the sulcus between the medial epicondyle and the olecranon.
The second site lies approximately 1 cm distal to the sulcus, where the nerve runs and between the two heads of the flexor carpi ulnaris muscle and the medial surface of the humerus. 8
27.5 Indications and Contraindications
ECuTR is indicated for patients with ulnar neuropathy at the elbow suspected by history of paresthesia or numbness in the ulnar nerve distribution, with positive physical findings (including Tinel’s sign over the ulnar nerve at the elbow) and elbow flexion-compression test with electrodiagnostical confirmation and unresponsive to conservative treatments.
Ulnar nerve instability is considered a contraindication for simple decompression because of the risk of painful instability after decompression that could necessitate revision surgery with ATUN.
In fact, for patients with preoperative evidence of ulnar nerve instability at the cubital tunnel or for those who develop ulnar nerve instability after endoscopic decompression, the procedure should be converted into an open subcutaneous or submuscular transposition.