Background: Increasing evidence supporting the clinical effectiveness of cooled radiofrequency ablation (RFA) therapy for genicular nerves in patients with chronic knee osteoarthritis (OA) exists. However, no study has been conducted to eliminate the potential influence of a placebo effect associated with this procedure. Therefore, we evaluated the efficacy of cooled RFA compared with a sham procedure in patients with painful knees due to OA. Methods: In this double-blind, randomized, controlled study, participants were randomly assigned to receive cooled RFA of the knee (cooled RFA group, n = 20) or a sham procedure (sham group, n = 20). The primary outcome was the proportion of successful responders at the three-month follow-up. The secondary outcomes were successful responders at one and six months; pain intensity of the knee; functional status; medication; and satisfaction at one, three, and six months after the procedures. Results: For the primary outcome, the successful responder rate was significantly higher in the cooled RFA group (76.5%) than in the sham group (33.3%) (p = 0.018). For the secondary outcome, more successful responders were observed in the cooled RFA group than in the sham group at one and six months after the procedure (p = 0.041 and 0.007, respectively). The decreased knee pain intensity was maintained throughout the six-month follow-up period in the cooled RFA group. No differences were observed in functional status, medication change, or satisfaction in both groups. Conclusions: The cooled RFA of genicular nerves offers significant pain relief and surpasses the effects attributable to a placebo.

Myong-Hwan Karm, Hyun-Jung Kwon, Chan-Sik Kim, Doo-Hwan Kim, Jin-Woo Shin, and Seong-Soo Choi. Korean J Pain 2024;37:13-25. https://doi.org/10.3344/kjp.23344

Hyun-Jung Kwon, Chan-Sik Kim, Sungwon Kim, Syn Hae Yoon, Jungho Koh, Young Ki Kim, Seong-Soo Choi, Jin-Woo Shin, and Doo-Hwan Kim. Korean J Pain 2023;36:358-68. https://doi.org/10.3344/kjp.23092

Background. In patients with postherpetic neuralgia (PHN), the effectiveness of epidural block and the benefits of adjuvant hypertonic saline (HS) have not been fully determined. Therefore, we investigated these issues in this study. Methods. At a tertiary medical center’s single pain clinic in Seoul, Republic of Korea, patients complaining of PHN even after 4 months of herpes zoster onset were enrolled and randomly assigned to either the HS or normal saline (NS) group. After epidural block with adjuvant HS or NS administration according to each protocol, outcomes were assessed at baseline and one and three months after the intervention. The primary outcome was pain intensity on the numerical rating scale (NRS). The secondary outcomes were the insomnia severity index (ISI), the medication quantification scale (MQS), and the global perceived effect of satisfaction (GPES). Results. Thirty-six patients (NS: 17, HS: 19) were included in the intention-to-treat analysis. The estimated pain intensity decreased in both groups at one and three months after the procedure ( < 0.001), without a significant group difference. The estimated ISI and MQS were not significantly different at 1 month compared with baseline but significantly decreased at 3 months in each group ( < 0.001 and < 0.001, respectively), without group differences. In addition, there was no difference between the groups on the GPES scale at one and three months after the procedure. Conclusions. Epidural steroid injection may have the advantages of short-term pain relief, improved sleep quality, and decreased medication usage in patients with PHN. In addition, adjuvant HS administration with epidural steroid injection did not show beneficial effects in patients with PHN. Further studies are needed to clarify the potential effectiveness of HS in treating neuropathic pain such as PHN. This trial is registered with KCT0002845.

Hyun-Jung Kwon, Kyunghwan Jang, Jeong-Gil Leem, Jin-Woo Shin, Doo-Hwan Kim, and Seong-Soo Choi. Korean J Pain 2021;34:479-86. https://doi.org/10.3344/kjp.2021.34.4.479

Cervical epidural block (CEB) is an effective intervention for managing cervical radicular pain. This study aimed to investigate the current status of performing CEB in South Korea. Pain physicians affiliated with the Korean Pain Society were asked to complete anonymous questionnaires regarding CEB between September and October 2022. The questionnaire consisted of 24 questions assessing the current status and methods of CEB in detail. Of the 198 surveys collected, 171 physicians (86.4%) reported performing CEB. Among those, the majority (94.7%) used fluoroscopy during the procedure. The paramedian interlaminar (IL) approach was the most preferred method (50.3%). Respondents performing fluoroscopic-guided IL CEB were categorized into two groups based on clinical experience: those with ≤10 years of experience (≤10-year group, n = 91) and those with >10 years of experience (>10-year group, n = 71). The proportion of physicians obtaining informed consent in the ≤10-year group and >10-year group was 50.5% and 56.3%, respectively. When entering the epidural space during IL CEB, the contralateral oblique view was the second most frequently used in both groups (≤10-year group, 42.9%; >10-year group, 29.6%). In targeting the upper cervical lesions (C3-4), the proportion of respondents who used an IL space higher than C6-7 was 17.6% in the ≤10-year group and 29.5% in the >10-year experience group. This study demonstrated variability in the CEB technique used by pain physicians in South Korea. The findings highlight the need for education on informed consent and techniques to enhance safety.