Sixty-eight patients with carpal tunnel syndrome diagnosed by history and clinical examination underwent open carpal tunnel release surgery. Electrodiagnostic studies were obtained preoperatively on all 68 patients but the authors did not review the results until after surgery. Sixty-three patients experienced prompt improvement in their symptoms following surgery. Fourteen of these 63 patients were found to have had normal electrodiagnostic studies. Five patients either did not improve or had only an equivocal response to surgery. Three of these patients had normal electrodiagnostic studies. The authors conclude that neurophysiological assessment is not necessary in patients who present with typical carpal tunnel symptomatology. The proposed benefits include diminished cost and less likelihood of diagnostic confusion.
The decision on whether or not to obtain an electrodiagnostic studies before carpal tunnel surgery remains controversial. Several previous studies have also shown a false negative rate with neurophysiologic testing. Electrical assessment is valuable in cases where the clinical presentation is atypical and the diagnosis uncertain. It may also be helpful in providing a baseline for the small number of patients who do not improve after surgery and for those with recurrent symptoms. Additional sites of compression and coexisting polyneuropathies can occasionally be identified. This information may be valuable in patient counseling and appropriate surgical decision making.