Fall 2003 Volume 16, Number 2	New from Hopkins: Saving the Energizer Money
	During a study on spinal cord stimulation (SCS)-a tried-and-true way to relieve chronic pain-researchers noted clear advantages to automating part of the technique. But a significant side benefit also surfaced: longer life for batteries. The multicenter study, led by Hopkins neurosurgeon Richard North, M.D., followed 44 patients who'd received SCS to ease chronic lower back or leg pain, the most common application. In SCS, surgeons ease electrodes into the dorsal epidural space just above a patient's spinal cord. The electrodes connect to a battery-powered pulse generator implanted beneath the skin. And an external control panel lets clinicians turn them on.
Yet choosing the right mix of electrodes to activate for each patient isn't easy. A mere eight electrodes, for example, gives 6,050 possible combinations. Getting the areas of "buzz" from each electrode to overlap the pain-a usual success signal-eats up vast amounts of time, says North. "The complexity of the set-up threatened to overshadow its advantages." So North's team devised a computerized system for adjusting stimulators. After a decade of refinements, it's now user friendly: Patients select their own settings within a clinician's predetermined range. The study, in the March Neurosurgery, shows the automated approach more technically accurate in picking useful electrodes. It's also faster than the manual way. But very important, it extends battery life by about 50 percent-no trivial matter when the battery set-up costs at least $15 grand. For more information, call 410-955-2438.