Minimally invasive placement of epidural plate electrodes under local anaesthesia in spinal cord stimulation

In the treatment of pain syndromes of different aetiologies a change has occurred from destructive interventions to stimulation procedures. Spinal cord stimulation is the best known example of this treatment strategy. It is used often in patients with persistent neuropathic pain syndromes in an extremity, for instance following low back surgery. This treatment is most frequently performed by a percutaneous placement of a single electrode, with the aid of a specially designed Tuohy needle to reach the epidural space. In cases where, for different reasons, a larger, plate electrode is needed, this has to be placed surgically by a small laminectomy. The general anaesthesia mostly needed for this procedure prevents trial stimulation necessary to check the correct electrode position. Besides this, the laminectomy procedure can subsequently result in new pain complaints due to the invasiveness of the procedure. To solve both problems we have modified the implantation technique. By using a tubular retractor system (METRx system, Medtronic Sofamor Danek, Memphis, TN), originally developed for minimally invasive degenerative disc surgery, it is possible to reach the epidural spinal space and introduce the plate electrode with a small approach under local anaesthesia both allowing trial stimulation and avoiding severe postoperative backache related to the approach in these patients.