The Impact of Dorsal Root Ganglion Stimulation on Pain Levels and Functionality in Patients With Chronic Postsurgical Knee Pain

Background: Chronic postsurgical pain is a considerable source of disabling neuropathic pain. Rates of knee replacement surgeries are increasing, and many patients report chronic postsurgical pain in their wake. When conventional therapies prove ineffective, neuromodulation options such as dorsal root ganglion stimulation (DRGS) may be used. However, little is known about the effect of DRGS on improvements in quantitative functional outcome parameters.

Materials and methods: In a prospective observational study at two pain centers, patients with chronic postsurgical knee pain underwent implantation with a DRGS system after an interdisciplinary multimodal pain program. Ratings of pain, mood, quality of life, and function were captured at baseline and through 12 months of treatment. Quantitative measures (range of motion, walking distance, and pain medication usage) were also recorded.

Results: Visual analog scale ratings of pain decreased from 8.6 to 3.0 (p < 0.0001; N = 11), and other pain measures agreed. Quality of life on the 36-Item Short Form Health Survey questionnaire improved from 69.3 to 87.6 (p < 0.0001), whereas the improvement in depression ratings was nonsignificant. International Knee Documentation Committee questionnaire ratings of function improved from 27.7 to 51.7 (p < 0.0001), which aligned with other functional measures. On average, knee range of motion improved by 24.5°, and walking distance dramatically increased from 125 meters to 1481. Cessation of opioids, antidepressants, and/or anticonvulsants was achieved by 73% of participants.

Conclusions: Both subjective-based questionnaire and quantitative examination-based variables were in broad agreement on the value of DRGS in improving functionality and chronic postsurgical pain in the knee. Although this finding is limited by the small sample size, this intervention may have utility in the many cases in which pain becomes problematic after orthopedic knee surgery.