TREATMENT OF THE POST-DISCOTOMY AND POST-FUSION SYNDROME BY SPINAL CORD STIMULATION (SCS) USING AN 8-POLE ELECTRODE AND DOUBLE-ELECTRODE SYSTEM. – PROSPECTIVE 3-YEAR STUDY RESULTS IN 37 PATIENTS.

Introduction: Revision procedures in pain syndromes following spinal operations can bring unsatisfactory results. When all therapies fail, there is the possibility of implantation of SCS. The 8-pole electrode and double-electrode technique broaden the spectrum. The purpose of this prospective study is to evaluate the results of the use of SCS in the technique cited in chronic lumbar pain syndrome of previously-operated patients. Methods: An SCS system was implanted in 37 previously-operated patients (16 f, 21 m; mean age 42 years) with therapy-resistant chronic lumbar pain syndrome (duration 31–62 months, all MPSS Grade III). All patients had undergone multiple surgery (2–5 times). 13 patients had also undergone fusion operation. The daily morphine dose applied ranged from 60–200 mg MST retard or equivalent. All patients also presented with somatizing tendencies. In addition to general criteria special measuring instruments were used. The follow-up period lasted 3 years. All patients could be included. Results: The external test phase lasted 15 to 45 days. 29 patients needed a double-electrode system. With the exception of one patient who was not included in the study, all patients desired permanent receiver implantation. Three times during the test phase there was dislocation of the electrode which could be corrected during receiver implantation. Three late dislocations could be corrected in one case by external repoling of the electrodes and in one case by revision under local anesthesia.. One patient required open implantation of a 16-pole plate electrode. All patients attained a reduction to MPSS grade II. The VAS revealed reduction by at least 4 categories, with maximum 7. Similar results were found in the specific back scores. In the SF-36, the level of the normal sample with back pain, ischias and disk damage was attained. The morphine dose could be reduced by at least 50%. 9 patients no longer required long-term medication. All results were stable throughout the follow-up period. All patients said they would have the procedure repeated. Discussion/Conclusion: SCS in 8-pole and double-electrode technique is a sufficient procedure in the therapy of chronic lumbar pain syndrome in previously-operated patients. Accurate indication and test phase are necessary. Even somatizing tendencies do not represent an absolute contraindication. Special attention must be paid to the complication of electrode dislocation.