An Experimental Evaluation of the Effects of Subarachnoid Injection of Phenol-Pantopaque in Cats

Abstract

T HIS study was undertaken in an attempt to explain certain puzzling phenomena observed in the clinical use of injections of phenol. 7 We had noted the incongruity of relief of subjective pain without diminution of sensibilities of pain and touch as tested for in the usual neurological examination. Others observing this phenomenon had hypothesized this was the result of selective destruction of the smaller fibers ~,2,s-1~ but histological verification of this hypothesis has not appeared in the literature. Furthermore, we sought an answer as to why, in spite of a uniform procedure, the results of injections of phenol often were unpredictable and, even more disturbing, why there often would be an early recurrence of pain or spasticity after what appeared initially to be a successful injection. Satisfactory human material for this s tudy was not available from our clinical series as the conditions treated were chronic and patients either died at home or in Inost instances are still alive. The few cases available for pathological s tudy were unsuitable for evaluating the histological changes wrought by the phenol, as the condition treated might well of itself have brought about the changes observed in the spinal cord or roots.