What Is the Best Surgical Procedure for Cubital Tunnel Syndrome?

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Chapter 10 What Is the Best Surgical Procedure for Cubital Tunnel Syndrome?

The second most common site of nerve compression in the upper extremity is the ulnar nerve in the region of the cubital tunnel. Until recently, the surgical management of cubital tunnel syndrome was represented in the literature by numerous case series with the authors reporting experience with a specific surgical procedure. Clinical research related to cubital tunnel syndrome answered many important questions about this disorder and its care; however, until recently, there has been only low-quality evidence supporting one type of surgical procedure over others.

In 1989, Dellon ¹ advocated a staging system for ulnar nerve compression at the elbow. He reviewed the literature and concluded that severity of compression, a characteristic he used to divide the syndrome into three stages, was an important prognostic factor and should be used to guide surgical management. Parallel to the staging of carpal tunnel syndrome, he divided cubital tunnel syndrome into “mild,” “moderate,” and “severe” stages. Although it remains unknown whether the stage of compression is an important guide for choice of surgery, if the prognosis of surgical care is related to the severity of compression, then this information would be useful in randomized trials to define the population and ensure balance of treatment groups.

For measurement of the results of cubital tunnel surgery, Kleinman and Bishop ² have devised a grading system. The domains include “satisfaction,” “improvement,” “severity of residual symptoms,” “work status,” “leisure activity,” “strength,” and “sensibility.”

This has been used widely since its introduction, and although it requires some measurement by a trained person, it is recommended for anyone performing clinical research in cubital tunnel syndrome. As a disorder causing symptoms and functional problems in the hand, in clinical research, some patient-oriented method of evaluation of the results of treatment should be used. The use of electrodiagnostic testing to measure the outcome of cubital tunnel surgery may be misleading. It has been reported that electrodiagnostic testing may not be accurate after anterior transposition.³ In addition, in other forms of nerve compression, electrodiagnostic tests may not return to normal despite good clinical results after surgery. The importance of these measurement issues in the use of electrical testing to evaluate the results of cubital tunnel surgery has not been explored. These concerns add to the importance of patient-oriented measures in outcomes research in cubital tunnel syndrome.

OPTIONS

The surgical options for cubital tunnel syndrome include three main decisions with some variation. The nerve can be decompressed and left in its normal anatomic position. This can be performed with a standard open approach or through a minimal incision method. The epicondyle can be removed in conjunction with release. The nerve can be transposed anterior to the epicondyle into a subcutaneous, an intramuscular, or a submuscular position.

Simple Release

The value of simple release of the ulnar nerve is that it is technically simple to perform and, if successful, causes the least morbidity for the patient. The surgery is of short duration and the postoperative care is simplified requiring no prolonged immobilization. This procedure leaves the nerve in its anatomic position, and therefore reduces the chance of inducing secondary compression by changing the anatomic course of the nerve. The concern with the procedure is that the nerve is left in a position behind the elbow where it can continue to undergo traction with full elbow flexion. Another potential problem is created because the nerve is released from its tethers within its anatomic bed. Theoretically, this increases the potential for subluxation of the nerve with flexion of the elbow. A variation of simple release is to use minimal incisions and some type of “endoscopic” visualization of the procedure. Nathan and colleagues ⁴ report 89% good or excellent immediate postoperative relief of symptoms using simple decompression of the nerve in 164 nerves in 131 patients. At an average follow-up period of 4.3 years, 79% of patients still reported good or excellent relief.

Epicondylectomy

The nerve is released as in a simple release and a portion of the medial epicondyle is removed to perform medial epicondylectomy. This procedure also leaves the nerve in its anatomic position. By combining a simple release with epicondylectomy, theoretically, when the elbow flexes, the nerve will not snap over the medial epicondyle. A minimal degree of epicondylar excision appears to be as effective as a partial epicondylectomy.⁵

Subcutaneous Transposition

Subcutaneous transposition places the nerve anterior to the axis of flexion of the elbow joint, preventing tension of the nerve by elbow flexion. The theoretic advantage of this procedure is that the nerve is moved out of the site of compromise into a tension-free environment. Compared with the submuscular transposition, the subcutaneous transposition should have a shorter recovery time. Potential problems with the procedure include introducing a new site of compression such as the medial intermuscular septum or fascial septae in the flexor origin. One variation of the procedure is to create a fascial sling for the nerve to prevent it from subluxing back behind the elbow. This sling can also create a site of compression. In thin people, the nerve may not have much coverage in the subcutaneous plane and may be sensitive.

Intramuscular and Submuscular Transposition

For intramuscular and submuscular transposition, the nerve is removed from its anatomic location and placed within ² or deep to the flexor pronator muscle origin. In this procedure, the nerve is placed anterior to the elbow and is placed within a protective environment. The surgeon may introduce additional sites of compression, and the patient must have a period of postoperative immobilization to allow the flexor origin to heal. One variation is to perform lengthening of the flexor pronator origin to loosen this structure over the nerve. In Dellon’s⁶ report of submuscular transposition on 121 patients and 161 extremities using the musculofascial lengthening technique, 88% of patients had an excellent or good result with a 7.5% failure rate. In Pasque and Rayan’s⁷ study, 84% of patients had good or excellent grades after submuscular transposition with a Z lengthening.

EVIDENCE

In an attempt to compare all these procedures, Dellon ¹ compiled the literature on each procedure. In his article, he reviewed the previous 90 years of literature and concluded, “This study demonstrates that despite more than 50 reported series of patients treated for ulnar nerve compression at the elbow, a collective experience with more than 2000 patients, there are at present no statistically significant guidelines based on prospective randomized studies for choosing one operative technique over another.”¹

Dellon ¹ found that in mild compression, the literature supported nonsurgical management with an expectation of 50% of patients achieving excellent results and almost 100% of patients achieving excellent results with any of the five common surgical procedures. For moderate compression, he noted that the literature suggested the anterior submuscular technique yielded the most excellent results with the least recurrence, and for severe compression, the intramuscular technique yielded the fewest excellent results and the most recurrence.

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