Fluoroscopic Confirmation of Needle Location in Ultrasound-guided Genicular Nerve Radiofrequency Thermocoagulation.

Abstract

Radiofrequency thermocoagulation of genicular nerves is an effective treatment for chronic pain due to knee osteoarthritis. The procedure can be performed under fluoroscopic or ultrasonographic guidance. The aim of this study was to fluoroscopically check the final location  of the needle in ultrasound-guided genicular nerve radiofrequency thermocoagulation and evaluate the treatment's success in patients with knee pain. A 2-center, prospective study. A private clinic and a tertiary care health center. Thirty-two patients who had unilateral knee pain, and grade 3-4 knee osteoarthritis according to the Kellgren-Lawrence classification were included. Following diagnostic genicular nerve blocks in patients whose knee pain was relieved by >= 50%, radiofrequency thermocoagulation was applied to these nerves. The final position of the needle was checked via fluoroscopy in anteroposterior and lateral planes. The needle was located in the one-third anterior portion of the bone shaft in 69 of 96 patients (71.9%), between one-third and two-thirds in 21 (21.9%), and in the one-third posterior portion in 6 (6.3%). The mean Numeric Rating Scale score for pain was 7.69 ± 0.99 before treatment, 4.03 ± 1.26 at one week, 2.53 ± 1.24 at one month, and 2.19 ± 1.71 at 3 months, indicating a statistically significant decrease (P < 0.001). The lack of a study group in which genicular nerve radiofrequency thermocoagulation was performed under fluoroscopy guidance could be cited among the limitations of this clinical study. The final position of the needle tip in radiofrequency thermocoagulation of genicular nerves can exist at the one-third anterior of the bone shaft, without a need for further advancing the needle to the posterior portion. Although performed more distally compared to fluoroscopy guidance, ultrasound-guided genicular nerve radiofrequency thermocoagulation still provides effective analgesia.