Bell's palsy: Results of surgery; salivation test versus nerve excitability test as a basis of treatment

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Abstract
One hundred fifty‐seven consecutive patients with Bell's palsy were evaluated between 1966 and 1971. In order to obtain a more homogenous group, the subjects were carefully screened by eliminating those with recurrent palsy, those not tested for both nerve excitability and salivary flow, those not followed until there was 100 percent return of function or for a period of 180 days, and those who were first evaluated beyond 10 days following onset of palsy. Applying these criteria, 76 patients were eliminated leaving 81 patients with Bell's palsy who were studied to evaluate the usefulness of the salivation and nerve excitability tests for selecting patients for surgery. Fifty‐four received no treatment while 22 were operated upon and five were treated with steroids.The study considered the prognostic application of salivary flow and nerve excitability testing. Patients with salivary flow rates of over 40 percent had a 92 percent chance of complete recovery, while those patients with salivary flow rates of less than 40 percent had a 70 percent chance of incomplete recovery. The nerve excitability test was slightly more accurate in that patients who maintained a normal response to electrical stimulation had a complete recovery rate of 92 percent while those with a decreased response had an incomplete recovery rate of 91 percent.There were six untreated patients with decreased response to nerve excitability, and all had incomplete return of facial function.Surgery based upon a decreased response to nerve excitability in 15 patients did not alter the natural history, since all 15 had incomplete return.There were five untreated patients with a salivary flow of 25 percent or less, and four had incomplete recovery.Surgery based upon a salivary flow of 25 percent or less with a normal response to nerve excitability changed the predicted outcome for complete recovery in seven patients from 20 percent to 70 percent. Five of the seven had complete recovery.Based on this study, it is doubtful that the nerve excitability test is useful as an indicator for surgery, while the salivary flow test seems to have great promise.