Conventional Radiofrequency Ablation of Genicular Nerves at 80°C – A One Year Retrospective Evaluation
Peter Shupper MD, Joseph Colao BS, Stephen Ellwood BS, Sofia Gilels BS, Rita Shah MD, Andrew Kaufman, MD
Rutgers New Jersey Medical School, Department of Anesthesiology, Newark, N.J.
Knee osteoarthritis (OA) is a common cause of chronic pain and decreased quality of life.(1) In patients with chronic pain despite conservative treatment or despite knee replacement, conventional radiofrequency ablation (RFA) of the genicular nerves may be a viable treatment.(2-4) However, few studies have evaluated the long-term efficacy of this procedure. Recently published studies have reported pain relief at 6 months with some patients reporting relief lasting as long as even 12 months.(2,3) In this study, we analyzed 29 genicular RFA procedures performed at 80°C to assess the degree of pain relief after 3, 6, and 12 months. Additionally, we compared these results to a prior study conducted at the same university-based interventional pain practice, which analyzed 3 and 6-month follow-up data from RFA procedures at 60°C.(3)
This study was conducted at a university-based interventional pain practice over two-year period following institutional review board approval. We conducted retrospective chart reviews and performed post-procedure assessments (via telephone or chart review) on all patients that completed genicular nerve RFAs at 80°C (n = 29) under fluoroscopic guidance. Demographic data and pre-procedure clinical data were collected via chart review. Telephone assessments were performed at approximately 3, 6, and 12 months post-RFA, with questions pertaining to degree of pain relief (0% -100%), current VAS scores, and interventional treatments received after the RFA, among others. For subjects who were unable to be contacted during designated time points, a chart review for data was performed. If no data was available for a patient time point, a data imputation strategy was employed. We also compared degree of pain relief (0% - 100%) to patients who completed genicular nerve RFAs at 60°C at the same institution.
Data for 29 RFAs performed on 24 individual patients were included in the study (Table 1). Mean VAS pain scores at baseline, 3, 6 and 12 months post-RFA were 8.5, 4.2, 5.2, and 5.6 respectively, representing statistically significant (p<0.05) differences at follow-up period compared to baseline (Fig. 1). The proportion of procedures resulting in ≥50% knee pain relief were 65.0%, 45.0%, and 25.0% at 3, 6, and 12 months post-RFA, respectively (Fig. 2). When RFA 80°C was compared to RFA at 60°C at 3 and 6-month follow-up time points, no statistically significant difference was found (Fig. 3).
In this study, which includes prospectively and retrospectively derived data, we found a statistically significant decrease in patient mean VAS scores at 3, 6, and 12 months following the procedure, with nearly half and a quarter reporting greater than 50% relief at 6 and 12 months, respectively. Similar to RFA for the treatment of chronic pain due to other pain generators, the analgesic effects tended to decrease after around 6 months. Our results are also similar to those seen in another study, which was performed with ultrasound guidance instead of fluoroscopic guidance.(2) Ultimately, we conclude that genicular RFA at 80°C is a viable treatment for chronic knee pain, and that different temperatures may yield similar outcomes.