Spinal cord stimulation with percutaneous and plate electrodes: side effects and quantitative comparisons

Abstract

<jats:p>Spinal cord stimulation is limited by the uncomfortable side effects experienced by the patient as the amplitude of stimulation is increased. These side effects include local segmental paresthesias or motor responses, which are objectively demonstrable as frequency-following muscle contractions, attributable to dorsal root stimulation. The authors present evidence for another mechanism of stimulation-evoked discomfort, namely recruitment of small fibers in ligamentum flavum, which occurs when electrodes are inserted percutaneously and their contacts are exposed circumferentially; this does not occur with plate electrodes with insulated dorsal surfaces.</jats:p> <jats:p>In a consecutive series of 79 patients with postsurgical lumbar pain syndromes, percutaneous four-contact electrodes were tested at levels from T-8 through T-12. At one or more levels, 46% of patients described paravertebral, nonradiating discomfort, unaccompanied by frequency-following muscle contractions. This was observed most commonly at the T-8 and T-9 levels. The effect was ameliorated in some cases by using multiple cathodes in parallel, which reduced the current density at individual contacts.</jats:p> <jats:p>In 10 of these patients, this side effect interfered with an otherwise successful trial to such a degree that an insulated plate electrode was selected for permanent implantation at the same level as the percutaneous electrode. This eliminated the uncomfortable side effect completely in all patients. Intraoperative testing with the insulated plate electrode inverted (that is, contacts dorsal) reproduced the side effect in the majority of patients, indicating that structures dorsal to the electrode, such as fibers in ligamentum flavum, mediate the effect. Postoperative testing by computerized techniques demonstrated improved coverage of pain by stimulation paresthesias, with lower stimulation power requirements, using the insulated plate electrode.</jats:p> <jats:p>This technical limitation of percutaneous spinal cord stimulation electrodes, which may confound treatment if unrecognized, has been found to have a straightforward solution which indicates the underlying mechanism.</jats:p>

Epidural Anesthesia for Placement of Spinal Cord Stimulators with Paddle-Type Electrodes

“…Depending on type of the electrodes, these systems can be implanted percutaneously, or surgically by a small laminotomy [3][4][5][6][7][8] . Increasingly, electrode placement for SCS has been through the percutaneous route, rather than via laminectomy, to reduce costs and to take advantage of minimally invasive techniques.…”

Computer modelling of spinal cord stimulation and its contribution to therapeutic efficacy

“…43 ± 45 Because large a erents entering the dorsal horn are most probably activated near their entrance into the spinal cord, direct activation of dorsal horn elements seems to be unlikely. From a recent SCS study by North et al 46 it is likely that nerve ®bres in the ligamentum¯avum contribute to nonradiating discomfort sensations if a percutaneous electrode is used. Contrary to plate electrodes, these electrodes enable current¯ow dorsally in the epidural space and in the ligamentum¯avum.…”

Staggered Transverse Tripoles With Quadripolar Lateral Anodes Using Percutaneous and Surgical Leads in Spinal Cord Stimulation

“…This is in general agreement with the earlier clinical trials that compared the performance of percutaneous and surgical leads. 22,23,31 Moreover, a small pilot study by Rigoard et al 32 showed that stimulation using the commercial LAM 565 lead can provide bilateral paresthesia coverage of the back in patients with Failed Back Surgery Syndrome. Our modeling study with the same configuration of LAM 565 shows that the ability to selectively recruit DC fibers is diminished in comparison with the LAM QD (Figure 7).…”

“…Earlier clinical studies with surgical leads that reported results for low-back pain used single-column and dual-column surgical leads. 22,23,31 Bipolar contact combinations were configured on the leads. Such leads have electrode contacts that have a larger active contact surface area and are widely spaced in comparison with the LAM QD.…”

“…22 Surgical leads were shown to be technically superior to percutaneous leads in the management of low-back pain, in that they demonstrated improved pain coverage by stimulation paresthesias and required lower stimulation power. 22,23 Moreover, surgical leads, owing to their insulated backing, allow for a more efficient, unidirectional stimulation field and stable lead position having a low tendency to migrate. Such a lead seldom exhibits stimulation characteristics similar to those of a percutaneous lead.…”