Histological Findings following Intrathecal Injections of Phenol Solutions for Relief of Pain.

The nervous system from nineteen patients with malignant disease who had intrathecal injections for the relief of pain was examined. In eighteen patients one or more injections of phenol in iophendylate or glycerol had been given; in six of them injections of silver nitrate and phenol in iophendylate or glycerol were also given. In one patient a single injection of silver nitrate and phenol in glycerol had been given. Material was also examined from eleven cats which had phenol in iophendylate applied to posterior nerve roots. The histological findings in one of these cats are described here. A control series of spinal cords from forty patients with malignant disease of the pelvic organs or lower limbs who did not receive intrathecal injections was also examined. The main findings were as follows: (1) Phenol in iophendylate or glycerol causes degeneration of both large and small nerve fibres. (2) The phenol acts on the fibres in the nerve roots and not on the ganglia or the spinal cord. (3) Posterior root degeneration was found in all the injected cases. It is concluded that at least some of this degeneration in each of the injected cases is due to the injection. (4) No evidence of excessive pathological reactions due to the injected solutions was found, with one exception. In this patient, who received a single injection of silver nitrate in phenol in glycerol, meningitis developed and led to death forty hours later.