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DC stimulation can improve functional outcome of lumbar spinal fusion
However, study finds no benefit to direct current stimulation in increasing fusion rate.
The functional outcome of lumbar spinal fusion can be improved in patients older than 60 years through the use of direct current stimulation, according to a recent study.
The study also found that direct current (DC) stimulation did not impact fusion rates, which were low in the studied population.
The findings were presented by Thomas Andersen, MD, PhD, at the International Society for the Study of the Lumbar Spine 2009 Annual Meeting in Miami, Florida.
According to Andersen, the increased risk of complications and lower fusion rates after spinal fusion surgery in older individuals means that discovering procedures which shorten operating time and reduce complications should be a priority.
“Most of the literature … tends to focus on complication rates,” he said. “Any treatment that could limit the complication rates and improve operating time would be of interest.”
Better outcomes
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Image: Andersen T |
A total of 107 patients across five orthopedic centers were randomized to uninstrumented posterolateral lumbar spinal fusion with or without DC stimulation. Fusion rates were assessed 2 years postoperative using thin-slice CT. According to the study, the Dallas Pain Questionnaire (DPQ), SF-36 and Low Back Pain Rating Scale index were all used to assess functional outcome.
Of the 107 patients, follow-up data were available for 95. The study reported that DC-stimulated patients had “significantly” better outcomes in three out of four categories in the DPQ and better SF-36 scores; however, researchers noted no differences in pain scores.
The stimulated group also experienced an improved median walking distance at their latest follow-up. The researchers noted that walking distance was significantly associated with functional outcome.
Despite these observations, the fusion rate was referred to as being “surprisingly low” and DC stimulation was found to have no effect on it. Those in the DC stimulation group experienced a 35% rate, vs. 36% seen in the control group. Low fusion rates were also attributed to women and smokers. Those patients who did achieve a solid fusion, the study reported, had superior functional outcome and pain scores at their latest follow-up.
“Interesting and surprising”
“We concluded that DC-stimulated patients tended to have better functional outcomes than controls,” Andersen said. “Thin-slice CT revealed high nonunion rates after uninstrumented spinal fusion in older patients without any effect of DC stimulation on fusion rates. The achievement of a solid fusion was associated with superior functional outcome.”
The study was labeled “interesting and surprising” by Orthopedics Today Editorial Board member Steven R. Garfin, MD.
“Existing literature suggests DC stimulation enhances posterolateral fusion, which by that process should improve outcomes,” Garfin told Orthopedics Today. “Herkowitz and colleagues have shown in a series of articles that for leg symptoms from spinal stenosis related to degenerative spondylolisthesis, a solid fusion leads to better results than pseudarthrosis, which leads to deteriorating results over time – greater than 2 years.”
“It is difficult to understand why Anderson’s patients with DC stimulation did better clinically than those without — with lower than anticipated fusion rates in both groups — unless there was a local TENS kind of effect,” he said.
For more information:
- Thomas Andersen, MD, PhD, can be reached at the Orthopaedic Research Laboratory, Building 1A, Aarhus University Hospital, Norrebrogade 44, 8000 Aarhus C, Denmark.; e-mail: tba@dadlnet.dk. He has no direct financial interest in any company or product mentioned in this article.
- Steven R. Garfin, MD, is professor and chair of the Department of Orthopaedic Surgery and the University of California, San Diego. He can be reached at 350 Dickinson St., MC 8894, San Diego, CA 92103-8894;. 619-543-2644; e-mail: sgarfin@ucsd.edu. He has no direct financial interest in any company or product mentioned in this article.
Reference:
- Andersen, T. The effect of DC stimulation on lumbar spinal fusion in older patients: A randomized clinical multi-center trial. Paper #7, presented at the International Society for the Study of the Lumbar Spine 2009 Annual Meeting. May 4-8, 2009. Miami, Florida.