Medial Brachial and Antebrachial Cutaneous Nerve Injuries: Effect on Outcome in Revision Cubital Tunnel Surgery

Author(s): Sarris I, Gobel F, Gainer M, et al.

Source: Journal of Reconstructive Microsurgery 18: 665-670, 2002

Summary:

This paper analyzes a retrospective series of 20 patients treated by one surgeon for failed cubital tunnel operations.  All 20 patients presented with complaints of persistent medial elbow pain.  Associated symptoms of hand pain, paresthesias about the incision and in the distal nerve territory, weakness, fatigue, and loss of dexterity were also present in varying degrees.  Physical findings were outlined, including altered ulnar sensation and 2-pt. discrimination, hypothenar atrophy, Tinel?s sign over the ulnar nerve, and a positive elbow flexion test.  Electrodiagnostic studies were performed on all patients prior to re-operation.  Surgery was performed for incapacitating medial elbow pain, in isolation or in combination with some or all of the above symptoms.  The operative revision depended in part on the type and number of prior operations.  Sixteen of 20 patients had only one previous operation.  These were divided amongst anterior subcutaneous transposition (n=8), anterior submuscular transposition (n=4), simple decompression (n=2), and medial epicondylectomy (n=2).  All patients were examined for neuromas in the region of the previous operation.  Findings consistent with neuroma were a Tinel?s sign, a tender mass, and symptoms with direct pressure on the mass.  Eight patients were felt to have neuromas prior to reoperation.    Neuromas, when found, were treated with proximal dissection, cauterization, and transposition into a submuscular plane.  If cutaneous nerves in the region of preoperative symptoms were found to be adherent to scar, neurolysis was performed.  All patients underwent neurolysis of the ulnar nerve and placement in a subcutaneous or submuscular plane. 

The results of reoperation were analyzed at a mean of 26 months after the procedures.  Sixty-five percent of patients were noted to have pathology of the medial antebrachiocutaneous and medial brachial cutaneous nerves.  A sensory neuroma of the MACN was found in 30%.  Neuromas were found in both nerves in 10%.  Dense scarring about both nerves without neuroma formation was noted in 20%.  All patients with isolated neuromas improved following resection and transposition of the neuromas.  Patients with symptoms of medial cutaneous nerve pathology, but without neuromas, had continued symptoms postoperatively.  Results were divided into 20% excellent, 55% good, 20% fair, and 5% poor (one patient).  Involvement of the medial cutaneous nerves with either neuroma, scarring, or obliteration correlated with a poorer outcome, although this was not statistically significant (p=0.065).  No recurrent neuromas were found on postoperative evaluation.  The authors conclude that the presence of pathology of the medial cutaneous nerves about the medial elbow incision following prior cubital tunnel surgery is a common contributing cause of primary failure.  Furthermore, severe scarring of the cutaneous nerves portends a worse prognosis following revision of cubital tunnel surgery than does the presence of a sensory neuroma. 

This paper identifies one source of ongoing pain following cubital tunnel surgery, injury to the medial cutaneous nerves about the incision.  This is often not appreciated when evaluating these patients postoperatively.  Results suggest that injury to these nerves adversely affects the results even after revision of the primary operation.  The authors emphasize the importance of identifying and protecting these nerves in the initial subcutaneous exposure of the cubital tunnel.  Indeed, only 35% of the patients presenting with a poor outcome following cubital tunnel surgery had pathology in the ulnar nerve bed alone.  This paper is compromised somewhat by the small sample size.  In addition, the actual incidence of this problem and clinical significance for all patients treated surgically for  cubital tunnel syndrome cannot be determined from this select group of patients.


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Journal of Reconstructive Microsurgery