April 1, 2015
Carpal tunnel release in patients with nerve conduction studies which are normal.
There has been a little bit of a controversy over the years on who is a candidate for surgery of the carpal tunnel. Neurologists have frequently been misguided into thinking that a nerve conduction study is prognostic when, in fact, a number of studies have shown that a nerve conduction study is not prognostic, i.e. we can’t use it to predict the result of the surgical treatment of whether that surgery is necessary. A nerve conduction study that is abnormal, however, and confirms the problem in a person who has symptoms then they have met the criteria, if they are otherwise healthy, for undergoing surgery.
But what about the patient who has symptoms compatible with carpal tunnel syndrome and a normal nerve conduction study? You can wait a long time and it frequently will become abnormal eventually with the person suffering in the interim. There have been a few studies over the years that have been specifically looked at, particularly that of Grundberg, et al., in Iowa showing the good results in nerve conduction study-negative patients. However, just about every study where the results of carpal tunnel release have been looked at have included some of these people, there just hasn’t been enough of them for the authors to scrutinize their outcomes.
Most recently in a poster exhibit, number 2071, October 3, 2013, at the 68th Annual Meeting of the American Society of Surgeons of the Hand (ASSH), O.D. Stone, et al. from the United Kingdom presented their study with 557 patients who underwent carpal tunnel release with an abnormal nerve conduction study vs. comparing them to 19 patients who underwent carpal tunnel release in the presence of a normal nerve conduction study. Those with the evaluation criteria known as Dash Score were better one year after surgery than the patients who had had a positive nerve conduction study preop. The patients who had had normal nerve conduction studies that had underwent surgery were most likely to be women and they had worse outcomes. They concluded that patients undergoing decompression for clinical carpal tunnel syndrome (CTS) but negative NCS could still gain significant improvement and, if there are sufficient clinical grounds for a diagnosis of carpal tunnel syndrome but negative NCS, carpal tunnel release should not be withheld.