Estimulación medular crónica y síndrome de cirugía de espalda fallida. Resultados clínicos con la utilización de electrodos planos quirúrgicos / Spinal cord stimulation and failed back surgery syndrome. Clinical results with laminectomy electrodes

Introducción: La estimulación medular crónica es una técnica ampliamente aceptada en el tratamiento del dolor lumbar resultante de una cirugía de espalda fallida. Clásicamente la estimulación se ha venido realizando con electrodos percutáneos implantados bajo anestesia local y sedación, sin embargo, la facilidad de migración, así como la dificultad de reproducción de parestesias eléctricas en zonas amplias recogidas con los mismos, han hecho que cada vez más se recurra a la utilización de electrodos planos quirúrgicos, que presentaban como inconveniente la necesidad de una laminectomía y anestesia general para su implantación. Objetivos Presentar los resultados clínicos, los detalles técnicos, las ventajas y los beneficios de la implantación de electrodos planos de estimulación medular bajo anestesia espinal, en síndromes de cirugía de espalda fallida. Material y métodos La estimulación medular se realizó en un total de 119 pacientes (52 hombres y 67 mujeres), con edades comprendidas entre los 31 y los 73 años (47,3 de media). La anestesia epidural fue inducida con ropivacaína. En todos los casos, a través de una laminectomía mínima, se implantó en el espacio epidural un electrodo plano de 8 contactos o un electrodo plano de moderna generación de 16 polos. La situación definitiva de los electrodos se dispuso en función de la reproducción de parestesias eléctricas en la zona dolorosa de los enfermos. Los electrodos se conectaron con posterioridad a generadores de impulsos eléctricos de doble canal o recargables. Resultados Después de un seguimiento medio de 4,7 años, el resultado en cuanto a la mejoría de la situación dolorosa previa es satisfactorio, constatando una disminución del dolor del 58% en el axial y del 60% en el radicular, en más del 70% de los casos. Ninguno de los pacientes ha manifestado que el tiempo quirúrgico fuera doloroso o desagradable. No se han recogido complicaciones serias en el grupo, y en 6 de los casos se ha tenido que explantar el sistema por ineficacia o intolerancia de la neuroestimulación a largo plazo. Conclusiones: En este estudio, realizado en un número importante de pacientes, se ha utilizado la anestesia epidural para la colocación de electrodos planos de estimulación medular en síndromes de cirugía fallida de espalda o poslaminectomía. La técnica se ha mostrado segura, eficaz y satisfactoria

Introduction: Spinal cord stimulation is a widely-accepted technique in the treatment of back pain resulting from failed back surgery. Classically, stimulation has been carried out with percutaneous electrodes implanted under local anaesthesia and sedation. However, the ease of migration and the difficulty of reproducing electrical paraesthesia’s in large areas with such electrodes has led to increasing use of surgical plate leads, which have the disadvantage of the need for general anaesthesia and a laminectomy for implantation. Objectives: Our objective was to report the clinical results, technical details, advantages and benefits of laminectomy lead placement under epidural anaesthesia in failed back surgery syndrome cases. Material and methods: Spinal cord stimulation was performed in a total of 119 patients (52 men and 67 women), aged between 31 and 73 years (average, 47.3). Epidural anaesthesia was induced with ropivacaine. In all cases we inserted the octapolar or 16-polar lead in the epidural space through a small laminectomy. The final position of the leads was the vertebral level that provided coverage of the patient’s pain. The electrodes were connected at dual-channel or rechargeable pulse generators. Results: After a mean follow-up of 4.7 years, the results in terms of improvement of the previous painful situation was satisfactory, with an analgesia level of 58% of axial pain and 60% of radicular pain in more than 70% of cases. None of the patients said that the surgery stage was painful or unpleasant. No serious complications were included in the group, but in 6 cases the system had to be explanted because of ineffectiveness or intolerance of longterm neurostimulation. Conclusions: This study, with a significant number of patients, used epidural anaesthesia for spinal cord stimulation of lead implants by laminectomy in failed back surgery syndromes. The technique seems to be safe and effective

[Spinal cord stimulation and failed back surgery syndrome. Clinical results with laminectomy electrodes]. / Estimulación medular crónica y síndrome de cirugía de espalda fallida. Resultados clínicos con la utilización de electrodos planos quirúrgicos.

INTRODUCTION: Spinal cord stimulation is a widely-accepted technique in the treatment of back pain resulting from failed back surgery. Classically, stimulation has been carried out with percutaneous electrodes implanted under local anaesthesia and sedation. However, the ease of migration and the difficulty of reproducing electrical paresthesias in large areas with such electrodes has led to increasing use of surgical plate leads, which have the disadvantage of the need for general anaesthesia and a laminectomy for implantation. OBJECTIVES: Our objective was to report the clinical results, technical details, advantages and benefits of laminectomy lead placement under epidural anaesthesia in failed back surgery syndrome cases. MATERIAL AND METHODS: Spinal cord stimulation was performed in a total of 119 patients (52 men and 67 women), aged between 31 and 73 years (average, 47.3). Epidural anaesthesia was induced with ropivacaine. In all cases we inserted the octapolar or 16-polar lead in the epidural space through a small laminectomy. The final position of the leads was the vertebral level that provided coverage of the patient's pain. The electrodes were connected at dual-channel or rechargeable pulse generators. RESULTS: After a mean follow-up of 4.7 years, the results in terms of improvement of the previous painful situation was satisfactory, with an analgesia level of 58% of axial pain and 60% of radicular pain in more than 70% of cases. None of the patients said that the surgery stage was painful or unpleasant. No serious complications were included in the group, but in 6 cases the system had to be explanted because of ineffectiveness or intolerance of long-term neurostimulation. CONCLUSIONS: This study, with a significant number of patients, used epidural anaesthesia for spinal cord stimulation of lead implants by laminectomy in failed back surgery syndromes. The technique seems to be safe and effective.

Multimodal navigation in the functional microsurgical resection of intrinsic brain tumors located in eloquent motor areas: role of tractography.

OBJECT: Nowadays the role of microsurgical management of intrinsic brain tumors is to maximize the volumetric resection of the tumoral tissue, minimizing the postoperative morbidity. The purpose of this paper was to study the benefits of an original protocol developed for the microsurgical treatment of tumors located in eloquent motor areas where the navigation and electrical stimulation of motor subcortical pathways have been implemented. METHODS: A total of 17 patients who underwent resection of cortical or subcortical tumors in motor areas have been included in the series. The preoperative planning for multimodal navigation was done by integrating anatomical studies, motor functional MR (fMR) imaging, and subcortical pathway volumes generated by diffusion tensor (DT) imaging. Intraoperative neuromonitoring included motor mapping by direct cortical stimulation (CS) and subcortical stimulation (sCS), and localization of the central sulcus by using cortical multipolar electrodes and the N20 wave inversion technique. The location of all cortically and subcortically stimulated points with positive motor response was stored in the navigator and correlated with the cortical and subcortical motor functional structures defined preoperatively. RESULTS: The mean tumoral volumetric resection was 89.1 +/- 14.2% of the preoperative volume, with a total resection (> or = 100%) in 8 patients. Preoperatively a total of 58.8% of the patients had some kind of motor neurological deficit, increasing 24 hours after surgery to 70.6% and decreasing to 47.1% at 1 month later. There was a great correlation between anatomical and functional data, both cortically and subcortically. A total of 52 cortical points submitted to CS had positive motor response, with a positive correlation of 83.7%. Also, a total of 55 subcortical points had positive motor response; in these cases the mean distance from the stimulated point to the subcortical tract was 7.3 +/- 3.1 mm. CONCLUSIONS: The integration of anatomical and functional studies allows a safe functional resection of the brain tumors located in eloquent areas. Multimodal navigation allows integration and correlation among preoperative and intraoperative anatomical and functional data. Cortical motor functional areas are anatomically and functionally located preoperatively thanks to MR and fMR imaging and subcortical motor pathways with DT imaging and tractography. Intraoperative confirmation is done with CS and N20 inversion wave for cortical structures and with sCS for subcortical pathways. With this protocol the authors achieved a good volumetric resection in cortical and subcortical tumors located in eloquent motor areas, with an increase in the incidence of neurological deficits in the immediate postoperative period that significantly decreased 1 month later. Ongoing studies must define the safe limits for functional resection, taking into account the intraoperative brain shift. Finally, it must be demonstrated whether this protocol has any long-term benefit for patients by prolonging the disease-free interval, the time to recurrence, or the survival time.

Epidural anesthesia for laminectomy lead placement in spinal cord stimulation.

BACKGROUND: Spinal cord stimulation (SCS) is used to treat chronic pain and requires an awake patient for optimized lead positioning to locate paresthesias. Epidural anesthesia may be a suitable anesthetic but has not been evaluated. METHODS: We performed an open-label, prospective, observational, single-center study to evaluate the safety and efficacy of laminectomy lead placement under epidural anesthesia for the treatment of neuropathic chronic pain. RESULTS: The results in our study demonstrate that epidural anesthesia is a suitable technique for SCS lead implant. CONCLUSIONS: This is the first study using epidural anesthesia for SCS lead implants by laminectomy. The technique seems to be safe and effective.