Use of a Tubular Retractor System as a Minimally Invasive Technique for Epidural Plate Electrode Placement under Local Anesthesia for Spinal Cord Stimulation: Technical Note

To improve the technique of placement of large plate electrodes for spinal cord stimulation with a minimally invasive approach using the METRx tubular retractor system (Medtronic Sofamor Danek, Minneapolis, MN). This dilating system splits the paravertebral musculature, avoiding the need to strip these muscles from the spine. The technique described makes it possible to perform the procedure (currently, it is most frequently performed using general anesthesia) with local anesthesia and sedation, allowing test stimulation, and with little intraoperative or postoperative discomfort for the patient.The tubular retractor system was used to approach the spine at the desired level using local anesthesia. A small laminectomy was performed through the working tube, and the plate electrodes were introduced by the same approach. Test stimulation could be performed to determine the correct electrode position because only local anesthesia was used.Seven patients were scheduled for placement of large plate electrodes for spinal cord stimulation. In six patients, with different indications for the placement of spinal cord stimulation, the electrode could be placed using the minimally invasive tubular retractor system approach with local anesthesia and slight sedation. A good test stimulation was obtained in all of the patients, resulting in good pain relief after definitive implantation. We were not able to perform the procedure in one patient because we could not reach the spinal canal at the level operated on previously. All patients experienced only acceptable postoperative back pain.Using a tubular retractor system, implantation of plate electrodes for spinal cord stimulation can be performed under local anesthesia with acceptable discomfort for the patient, making the approach of the spinal canal minimally invasive. This method allows test stimulation to assess the correct electrode position and results in less local postoperative discomfort because of the small-muscle splitting approach.