New approaches may increase effectiveness of SCS for severe back pain

New approaches to electrical stimulation—using an implanted device with three columns of electrodes—may increase the effectiveness of spinal cord stimulation (SCS) for severe back pain, suggests a study in the March issue of Neurosurgery, official journal of the Congress of Neurological Surgeons. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.

The "tripolar lead" device helps maximize the benefits of SCS for patients with "failed back surgery syndrome," and may lead to expanded use of electrical stimulation techniques. The new research was led by Dr. Philippe Rigoard of Poitiers University School of Medicine, Poitiers, France.

Overlapping Stimulation Patterns Provide Better Pain Relief
In SCS, a mild electrical current is applied to electrodes implanted along the spine. If successful, the stimulation produces a feeling of numbness that overcomes the sensation of pain. Past studies have reported success with SCS in patients with back and leg pain that doesn't respond to other treatments. Spinal cord stimulation has been most effective against "radicular" pain spreading down the leg. However, it has had limited success in treating "axial" pain along the spine—especially in the lower back.

Dr. Rigoard and colleagues evaluated a new approach to SCS in eleven patients who were left with severe pain after failed back surgery. All underwent surgical implantation of a recently approved stimulation device that includes three columns of electrodes, rather than just one.

The idea is that the 16 electrodes in the three-column configuration will provide overlapping areas of stimulation, thus maximizing the effects of SCS. Dr. Rigoard and colleagues systematically tested the effects of 43 different electrode stimulation patterns to determine which was most effective in relieving "axial" pain in the lower spine as well as "radicular" pain in the leg.

"The tripolar lead successfully generated paresthesia [numbness] in both bilateral back and leg territories in 9 patients (81.8%)," the researchers write. Stimulation patterns using two or three columns provided better pain relief than single-column patterns.

Reductions in Back Pain as Well as Leg Pain
After six months on stimulation, the patients had significant improvements in pain. On a scale of 0 to 10, the average total pain score (including both back and leg pain) decreased from 8.2 to 2.25.

The new tripolar lead and stimulation patterns may help to overcome the limitations of previous approaches to SCS, particularly for axial pain. Larger studies will be needed to confirm the effectiveness of the new approaches—particularly whether they help patients with severe, disabling back pain resume more normal activities.

If so, "This may lead physicians to reconsider new indications for spinal cord stimulation" Dr. Rigoard and colleagues conclude. They believe the new techniques have the potential to expand the use of SCS to larger numbers of patients with "intractable" back pain in the near future.