Dose Dependent Effects of tDCS on Post-Operative Pain

Overview

The proper control of acute and chronic pain is one of the most important areas in health care. Despite the profound advances in neuroscience over the past 20 years, the investigators still largely use opiate narcotics, much as was done in the Civil War. Total knee arthroplasty (TKA) is one of the most common orthopedic procedures performed 1. While knee pain is often a complaint that precedes TKA, the procedure itself is associated with considerable post-operative pain lasting days to weeks. Adequate postoperative pain control is an important factor in determining recovery time and hospital length of stay. New analgesic strategies are needed that can be used adjunctively to existing strategies with the potential to reduce reliance on opioid analgesia. Several novel brain stimulation technologies including transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are beginning to demonstrate promise as treatments for a variety of pain conditions. Electricity has no metabolite or other residue, and can be delivered with minimal discomfort and without problems associated with drug-drug interactions. In two independent preliminary pilot studies, the Investigators have shown that tDCS can reduce post-operative PCA use by as much as 46% while simultaneously reducing subjective pain ratings. The present study aims to determine the effects of transcranial direct current stimulation (tDCS) on post-operative pain, patient-controlled analgesia (PCA) use, and post-surgical complications during the 48-hour post-operative period following total knee arthroplasty.

The proposed study employs a randomized, double-blind, sham-controlled design to evaluate the effects of tDCS on pain among Veterans receiving unilateral total knee arthroplasty (TKA) and unilateral total hip arthroplasty (THA). Further, this study will examine dose-dependency of the tDCS analgesic effects. Each tDCS session delivered either 20 min of real or sham tDCS. Real tDCS was administered at 2mA whereas sham tDCS delivered none. 120 patients undergoing TKA will be randomly assigned to one of four groups:Group 1 will have 4 sessions of real tDCS, Group 2 - 2 sessions of real tDCS (+ 2 sham-sessions), and Group 3 - 1 session of real tDCS (+ 3 sham-sessions). Group 4 is "Sham" tDCS, which does not involve any real stimulation. The participants will receive 2 tDCS treatments on the day of their surgery, and 2 tDCS treatments the day after their surgery.