Acute post-fusion pain may be helped with transcranial direct current stimulation

SAN FRANCISCO — It was unclear from preliminary results of a prospective randomized controlled trial presented here how effective transcranial direct current stimulation may be after lumbar spine surgery in decreasing hydromorphone usage and impacting subjective pain ratings.

At the North American Spine Society Annual Meeting, John Glaser, MD, presented details for the 27 patients included in the study.

“We found a few differences, but generally I think our results do not tell us for sure one way or the other,” Glaser said.

The patients studied were a mean of 60 years old with 85% of patients were Caucasian and 15% of patients were African-American. The patients had lumbar fusions, after which they were immediately randomized to receive real or sham transcranial direct current stimulation (tDCS). This method has been shown to be effective in conjunction with pain after total knee arthroplasty and other procedures, but to the researchers’ knowledge there are no published studies looking at tDCS in association with spine surgery.

“We thought this would be an excellent opportunity to see if this also works for people who get major spine operations,” Glaser said.

Each patient completed four 20-minute sessions of real or sham tDCS during their hospital stay, which consisted of an anode placed over the superior motor cortex (2mA), as well as a cathode placed over the right dorsolateral prefrontal cortex.

Both groups used hydromorphone as patient-controlled anesthesia (PCA) and had their pump usage tracked. VAS pain scores were collected twice daily. The patients, surgeons and research assistants were blinded to who received real and sham tDCS.

Glaser showed a chart of hydromorphone use in the two groups during the hospital stay, which he said showed the real and sham groups used the PCA to nearly the same extent through about 40 hours after which PCA usage leveled off in the real group and increased in the sham group.

Average pump usage through discharge in the real tDCS group was 12.82 mg hydromorphone compared with 16.35 mg hydromorphone in the sham group, “suggesting that tDCS was associated with a 22% reduction in PCA usage,” according to the abstract.

However, Glaser said the VAS pain scores were not statistically different between the two groups.

“The only statistically significant value they could find was the slope of the curve of usage,” he said.

“The analysis of the visual analog scores from admission to discharge showed a greater percent increase in pain at its worst in the sham group and a greater percent decrease in pain at its best for the real group, and it compared 33% to 13%, although they were not statistically significant,” Glaser said. – by Susan M. Rapp

Reference:

Borckardt JJ. Transcranial direct current stimulation (tDCS) in the management of acute post-spine surgery pain: A prospective randomized controlled trial. Presented at: North American Spine Society Annual Meeting; Nov. 12-15, 2014; San Francisco.

Disclosure: The North American Spine Society provided financial support for this study through a research grant.