Effects and side effects of a percutaneous thermal lesion of the dorsal root ganglion in patients with cervical pain syndrome.

Twenty consecutive patients with intractable chronic pain in the cervical region were treated with a radiofrequency lesion of the dorsal root ganglion on level C4, C5 or C6. Electromyography (EMG) and sensory evoked potentials (SEP) were recorded before and 3 weeks after the radiofrequency lesion. Side effects were studied 3 weeks, 6 weeks and 3 months after the procedure. Pain scores were evaluated on Numeric Rating Scales (NRS) before and 6 weeks after treatment. The patient was interviewed 3, 6 and 9 months after the radiofrequency lesion. The most common side effect was burning pain in the dermatome of the treated nerve root. Hyposensibility in the dermatome was noticed in 35% of patients. Except in 1 patient, these side effects had disappeared 6 weeks after treatment. The EMG showed no signs of denervation. One SEP recording remained abnormal after treatment. There was initial pain relief in 75% of patients after 3 months and in 50% of the patients after 6 months. In conclusion, this study did not reveal any signs of motor denervation after a percutaneous partial rhizotomy. There were no long-term signs of deafferentation. Initial pain relief was found in 75% of patients, but there was a marked tendency for pain to recur in a period from 3 to 9 months after treatment.