Clinical experience with radiofrequency and laser DREZ lesions

Dorsal root entry zone (DREZ) lesions were used to treat intractable pain due to deafferentation in 78 patients managed between 1981 and 1988. Etiology of pain included avulsion of brachial or lumbosacral plexuses (27 cases), spinal cord injury (20 cases), amputation (nine cases), post-herpetic neuralgia (16 cases), and cauda equina injury (six cases). Three different lesioning techniques were employed: a radiofrequency (rf) method using a 0.5 X 2-mm stainless steel electrode with control of electric current and duration (Group 1: 21 cases); the CO2 laser (Group 2: 20 cases); and an rf method, using a 0.25 X 2-mm stainless steel electrode with control of electrode temperature and duration (Group 3: 37 cases). Overall, 48 (61.5%) of 78 patients received satisfactory pain relief, defined as a 50% or greater reduction in pain intensity, cessation of narcotic analgesic usage, and improvement in functional capacity. Fourteen (67%) of the 21 Group 1 patients obtained effective pain relief, compared to nine (45%) of the 20 Group 2 patients and 25 (68%) of the 37 Group 3 patients. Neurological complications including mainly ipsilateral leg weakness or loss of proprioception occurred in 52.3% of the patients in Group 1, 15% of the Group 2 patients, and 8.1% of the Group 3 patients. These results support the view that DREZ lesions may be made most effectively and safely with the rf lesioning technique associated with control of electrode temperature and duration.