Spinal cord stimulation revisited

The proportion of patients with intractable pain successfully managed with spinal cord stimulation (SCS) remains disputed. We analyze 27 consecutive patients with intractable pain treated with SCS using identical hardware (Itrel II System; Medtronic Neurological, Inc Minneapolis, MN, USA) by a single satisfactory diagnosis 1992 through 1995. A rigid selection protocol was used: 1. A satisfactory diagnosis of the pathologic process resulting in pain was made. 2. A corrective surgical procedure was judged not feasible by surgeons experienced in the particular pathology, e.g., vascular peripheral nerve, spine. 3. Lack of satisfactory response to noninterventional pain management modalities by an interdisciplinary pain clinic. 4. Independent psychological evaluation, including a structured interview was performed by a psychologist specialized in chronic pain management. In the last eight cases, a battery of self-report tests designed to assess psychosocial and behavioral consequences of the chronic pain problem were administered as well. All cases were of nonmalignant pain, except for one patient. Thirteen cases were diagnosed with failed back surgery syndrome (FBSS), one older patient with lumbosacral radiculopathy who refused decompression, one cervical radiculopathy and Klippel-Feil syndrome, six with reflex sympathetic dystrophy (RSD), two with peripheral vascular ischemic disease, one with post-thoracotomy pain syndrome, one with leg pain following resection of angiolipoma, one with traumatic superficial peroneal neuropathy, and one with Pancoast's tumor. Fifteen patients were female and twelve were male. All were Caucasian. Their ages ranged from 27 to 84 years (mean:48). The average follow-up was 21 months (range: 48-6). All patients underwent a three day trial screening with Pisces-Quad/Resume epidural leads connected to a temporary external stimulator. An Itrel II System pulse-generator was internalized in each of the 24 patients who had successful trial (three cervical and twenty-one thoracic-lumbar). There was no morbidity. Pain reduction was sustained in 22 out of the 24 patients who continue to use the stimulator. The same number would choose to receive in an electrical stimulator again. Normalization or improvement in Quantitative Sudomotor Axon Reflex Test (Q-SART) and Thermography was documented in the patients with RSD. We conclude that rigid selection protocol can maximize the proportion of patients with intractable pain who are successfully treated with SCS. Strict neurosurgical technique eliminates infection risk. Hardware selection minimizes incidence of malfunction.