Microsurgical DREZotomy for pain due to spinal cord and/or cauda equina injuries: long-term results in a series of 44 patients.

According to the literature estimations, 10-25% of patients with spinal cord and cauda equina injuries eventually develop refractory pain. Due to the fact that most classical neurosurgical methods are considered of little or no efficacy in controlling this type of pain, the authors had recourse to microsurgery in the dorsal root entry zone (DREZ). This article reports on the long-term results of the microsurgical approach to the dorsal root entry zone (DREZotomy) in a series of 44 patients suffering from unbearable neuropathic pain secondary to spine injury. The follow-up ranged from 1 to 20 years (6 years on average). The series includes 25 cases with conus medullaris, 12 with thoracic cord, four with cauda equina and three with cervical cord injuries. Surgery was performed in 37 cases at the pathological spinal cord levels that corresponded to the territory of the so-called 'segmental pain', and in seven cases, on the spinal cord levels below the lesion for 'infralesional pain' syndromes. The post-operative analgesic effect was considered to be 'good' when a patient's estimation of pain relief exceeded 75%, 'fair' if pain was reduced by 25-75%, and 'poor' when the residual pain was more than 75% of preoperative estimations. Immediate pain relief was obtained in 70% of patients and was long-lasting in 60% of the total series. The results varied essentially according to the distribution of pain. Good long-term results were obtained in 68% of the patients who had a segmental pain distribution, compared with 0% in patients with predominant infralesional pain. Regarding pain characteristics, a good result was obtained in 88% of the cases with predominantly paroxysmal pain, compared with 26% with continuous pain. There were no perioperative mortalities. Morbidity included cerebrospinal fluid leak (three patients), wound infection (two patients), subcutaneous hematoma (one patient) and bacteremia (in one patient). The above data justify the inclusion of DREZ-lesioning surgery in the neurosurgical armamentarium for treating 'segmental' pain due to spinal cord injuries.