Gross and Microscopic Lesions Produced by Phenol Neurolytic Procedures

Abstract

The primary purpose of this brief discourse is to show, in pictorial form, the morphological changes that occur when phenol is applied to neural structures. According to Katz and Joseph [1], most studies on morphologic changes caused by neurolytic agents have been done with phenol. It generally is accepted that the primary neurolytic effect is a result of protein denaturation. When concentrations of 5% or more in water are applied directly to tissue, protein coagulation and necrosis occur. However, phenol has been suggested to have a greater affinity for vascular tissue than for neuronal tissue, thereby tending to cause neural lesions via interference with blood flow [2, 3]. When we [4] compared morphological changes that occurred following epidural and subarachnoid injection of phenol, no spinal cord damage was noted in the former case (see figure 12–3). In contrast, massive neural tissue damage occurred following subarachnoid injection. Blood vessels with normal morphology were present in areas of spinal cord destruction (see figure 12–4), illustrating a direct neurotoxic effect of phenol rather than an effect secondary to vascular destruction.