Is Surgery Necessary for Carpal Tunnel Syndrome?
Is Surgery Necessary for Carpal Tunnel Syndrome?
By Bridget T. Carey, MD, Assistant Professor of Neurology and Neuroscience, Weill Cornell Medical College. Dr. Carey reports no financial relationships relevant to this field of study.
Synopsis: Surgery is useful for patients with carpal tunnel syndrome who have not yet manifested denervation on electrodiagnostic testing.
Source: Jarvik JG, et al. Surgery versus non-surgical therapy for carpal tunnel syndrome: A randomized parallel-group trial. Lancet 2009;374:1074-1081.
Compression of the median nerve at the wrist is the most common peripheral nerve entrapment syndrome. Carpal tunnel syndrome (CTS) manifests as numbness, paresthesias, pain, and weakness in the median nerve distribution. As such, CTS is one of the most frequent causes of disabling hand disorders. The treatment for CTS splits into two arms: surgical decompression versus non-surgical management. The latter category consists of varying combinations of "conservative" measures, including splinting the wrist into a neutral position nightly or for a significant portion of each day. Additional measures include eliminating occupational causes, non-steroidal anti-inflammatory (NSAID) medications, hand therapy, ultrasound therapy, and steroid injections.
The aim of the Jarvik study was to compare functional and symptomatic outcomes following surgical or non-surgical treatment for patients with CTS. One-hundred sixteen (116) patients with a diagnosis of CTS were randomized into either surgical or non-surgical treatment groups. Diagnosis was made primarily on clinical criteria. Electrodiagnostic inclusion criteria were defined; however, the presence of electrodiagnostic abnormalities was not necessary to establish a diagnosis of CTS if sufficient clinical criteria were met. Patients with severe CTS were excluded from the study. Severe CTS was determined by the presence of thenar muscle wasting, abnormal two-point discrimination > 6 mm, and / or electrodiagnostic evidence of denervation.
The surgical group underwent either endoscopic or open carpal tunnel decompression within the first three months after randomization. This was followed by hand therapy, per the surgeon's usual post-operative protocol. The non-surgical group was provided with customized hand therapy sessions, NSAIDs, and encouraged to continue splinting. If subjects in the non-surgical group failed to improve after six weeks, ultrasound therapy was added to the regimen. If subjects failed to improve after three months, individuals allocated to this group had the option to proceed to surgical decompression. Subjects in both groups were evaluated at six weeks, three months, six months, nine months, and 12 months after randomization. The Carpal Tunnel Syndrome Assessment Questionnaire (CTSAQ) for functional status was used as the primary outcome measure. Secondary outcome measures, including the CTSAQ for symptom severity, were also assessed. The CTSAQ consists of 9-11 questions, from which a "function" or "symptom" score of 1 through 5 is calculated, with 5 being most severe.
Both groups experienced symptomatic improvement throughout the experimental protocol. The surgically-treated group experienced slightly more improvement than the non-surgical group based on CTSAQ function scores, a difference of 0.4 points on the CTSAQ function scale. The authors concluded, however, that even though the differences were statistically significant, the differences were of questionable clinical significance. The investigators concluded that surgery is useful for patients with CTS, before denervation develops.
Commentary
CTS is not a complex disease. The work of Seddon and Sunderland has long established the pathophysiology of peripheral nerve injury, and the prognosis associated with varying degrees of injury.1 When a nerve is subjected to excessive pressure from an external force, myelin at the site of compression will degrade. If the rate of myelin degradation is slow, the surrounding Schwann cells are generally able to keep up with repair. If the external pressure is severe or prolonged, demyelination will progress faster than the rate of remyelination. If allowed to continue, the myelin sheath is essentially destroyed, and subsequent axonal injury ensues. In CTS, the median nerve is compressed by osseous and / or ligamentous structures in the carpal tunnel. This is a purely structural problem. If you decompress the tunnel, you stop the progression of injury.
A more important question than whether surgical intervention is helpful in CTS, is whether, and under what conditions, it is necessary. Assuming that the goal of treatment is to ensure a good functional and symptomatic outcome for patients, the purpose of treatment is to preserve nerve function. Whether surgery is needed to do this depends on the status of the median nerve. This study did not adequately address the extent of nerve injury in the enrolled patients, other than to exclude those with axonal injury (denervation). The extent of demyelination, however, can be ascertained through electrodiagnostic criteria. This was not done in this study. In many cases, CTS does not progress beyond the nerve's ability to repair itself, and we would not be helping these patients by subjecting them to surgery, even with a minimally invasive procedure with a low complication rate.
Reference
1. Seddon H, et. al. Three types of nerve injury. Brain 1943;66:237-288.
Surgery is useful for patients with carpal tunnel syndrome who have not yet manifested denervation on electrodiagnostic testing.Subscribe Now for Access
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