Subcutaneous Stimulation as ADD-ON Therapy to Spinal Cord Stimulation Is Effective in Treating Low Back Pain in Patients With Failed Back Surgery Syndrome: A Multicenter Randomized Controlled Trial.

OBJECTIVE: Suppression of back pain with traditional spinal cord stimulation (SCS) in failed back surgery syndrome patients is often insufficient. The objective of this study was to investigate the efficacy of subcutaneous stimulation (SubQ) as ADD-ON therapy to SCS in treating back pain in failed back surgery syndrome patients. MATERIALS AND METHODS: Patients with a minimal pain score of 50 on a 100 mm visual analog scale for both leg and back pain were eligible. If pain reduction after trial SCS was ≥50% for the leg but <50% for the back, patients received additional SubQ leads and were randomized in a 1:1 ratio in a study arm with subcutaneous leads switched on (SubQ ADD-ON) and an arm with subcutaneous leads switched off (Control). The primary outcome was the percentage of the patients, at three months since implantation, with ≥50% reduction of back pain. RESULTS: A total of 97 patients were treated with SCS for leg and back pain. Of these, 52 patients were randomized and allocated to the Control group (n = 24) or to the SubQ ADD-ON group (n = 28). The percentage of patients with ≥50% reduction of back pain was significantly higher in the SubQ ADD-ON group (42.9%) compared to the Control group (4.2%). Mean visual analog scale for back pain, at three months, was a statistically significant 28.1 mm lower in the SubQ ADD-ON group compared to the Control group. CONCLUSION: Subcutaneous stimulation as an ADD-ON therapy to SCS is effective in treating back pain in failed back surgery syndrome patients where SCS is only effective for pain in the leg.

The effect of spinal cord stimulation (SCS) on static balance and gait.

OBJECTIVES: To investigate whether spinal cord stimulation (SCS) has a negative effect on static balance and gait, which is implicated by the increased incidence of falls leading to frequently occurring lead migrations. MATERIALS AND METHODS: A controlled trial is performed with 11 subjects (four female, seven male) with a mean age of 46 years old. A baseline measurement consisting of static balance and gait tests was performed. Within two weeks after implantation of a spinal cord stimulator, subjects performed the same tests with both stimulation switched on and off. Static balance was assessed with eyes open and eyes closed on hard surface and foam surface. The velocity of the center of pressure and weight symmetry were the main outcome parameters. Kinematics and spatiotemporal outcome parameters were used to analyze gait. ANOVAs were used to compare between baseline, stimulation on, and stimulation off. RESULTS: Spinal cord stimulation resulted in significant pain relief as scored on a Visual Analog Scale (p < 0.001). Gait width decreased and this change (indicative of improvement in balance) was significant (p = 0.007). No other significant group differences were found between stimulation baseline and post-surgery measurements. SCS did not influence static balance or gait when group effects were analyzed. Four subjects showed significant differences in static balance between stimulation on and off. CONCLUSIONS: The lack of group differences in normal gait and static balance cannot explain the increased incidence of falls. However, four subjects showed an effect of SCS on static balance. Further research to clarify why only a part of the subjects experienced balance problems is recommended and assessments of more demanding balance and gait tasks are desirable.

Percutaneously implanted plates in failed back surgery syndrome (FBSS).

OBJECTIVE: To evaluate the clinical efficacy of pain suppression in back area and lower extremities by recently developed plate electrodes for spinal cord stimulation through percutaneous access. METHODS: A retrospective analysis is performed: 20 consecutive patients with both lower extremity pain and low back pain, with low back counting for at least 30% of the overall pain were implanted with a small profile plate type lead, S-Series (SJM), via percutaneous approach. Patients were asked to rate their back and leg pain as well as their overall satisfaction and data on quality of life (QOL) on a (0-10 point) visual analog scale (VAS) before and after implantation. Medication use, functional pain (pain when bending forward, moving), and patient satisfaction scores also were collected. RESULTS: A significant reduction of 55% and 45.7% in, respectively, VAS legs and VAS back pain was found. One year postoperatively the reduction was still present, respectively, 43% and 27% for the legs and the back. In 17 patients (85%) a clinically relevant reduction (defined as reduction of 2 points or 30% in VAS) in back pain was seen, with a mean decrease of 4.3 points (2.0-10.0) or 52% (22-100). Only three patients had no reduction in back pain, although they had reduction of their pain in the lower extremities. A significant and clinically relevant improvement of 66% and 70% was seen, respectively, for general satisfaction and QOL, respectively. One year postoperatively this improvement was still present, respectively, 69% and 75% for the satisfaction and QOL. Importantly functional pain also decreased by 51%. No infections occurred. Mean duration of post-op wound pain was 13.5 hours. CONCLUSION: Percutaneous implantation of the S-Series plate electrodes using a 10 gauge epidural needle combines the advantages of a minimal invasive technique with the possibility to cover the back area supplementing leg coverage in 85% of the failed back surgery syndrome patients.