A Retrospective Comparison of Low-Temperature Plasma Ablation and Radiofrequency Thermocoagulation of the Thoracic Nerve Root for Refractory Postherpetic Neuralgia
Authors: Tang Yuanzhang 
Published: January 2025

BACKGROUND: Radiofrequency thermocoagulation (RFT) of the thoracic nerve root is commonly employed in treating medication-refractory thoracic post-herpetic neuralgia (PHN). However, RFT procedures’ suboptimal pain relief and high occurrence of postoperative skin numbness present persistent challenges. Previous single-cohort research indicated that the low-temperature plasma coblation technique may potentially improve pain relief and reduce the incidence of skin numbness. Nevertheless, conclusive evidence favoring coblation over RFT is lacking.

OBJECTIVES: To compare the clinical outcomes associated with coblation to those associated with RFT in the treatment of refractory PHN.

STUDY DESIGN: Retrospective matched-cohort study.

SETTING: Affiliated Hospital of Capital Medical University.

METHODS: Sixty-eight PHN patients underwent coblation procedures between 2019 and 2020, and 312 patients underwent RFT between 2015 and 2020 in our department. A matched-cohort analysis was conducted based on the criteria of age, gender, weight, pain intensity, pain duration, side of pain, and affected thoracic dermatome. Pain relief was assessed using the numeric rating scale (NRS), the Medication Quantification Scale (MQS) Version III and the Neuropathic Pain Symptom Inventory (NPSI), which were employed to indicate pain intensity, medication burden, and comprehensive pain remission at 6, 12, and 24 months. Numbness degree scale scores and complications were recorded to assess safety.

RESULTS: We successfully matched a cohort of 59 patients who underwent coblation and an equivalent number of patients who underwent RFT as a PHN treatment. At the follow-up time points, both groups’ NRS, MQS, and NPSI scores exhibited significant decreases from the pre-operation scores (P < 0.05). The coblation group’s NRS scores were significantly lower than the RFT group’s at the sixth and the twenty-fourth months (P < 0.05). At 24 months, the MQS values in the coblation group were significantly lower than those in the RFT group (P < 0.05). Furthermore, the coblation group’s total intensity scores on the NPSI were significantly lower than the RFT group’s at the 12- and 24-month follow-ups (P < 0.05). At 6 months, the coblation group’s temporary intensity scores on the NPSI were significantly lower than the RFT group’s (P < 0.05). Notably, the occurrence of moderate or severe numbness in the coblation group was significantly lower than in the RFT group at 6 and 12 months (P < 0.05). No serious adverse effects were reported during the follow-up.

LIMITATIONS: This analysis was a single-center retrospective study with a small sample size.

CONCLUSION: In this matched cohort analysis, coblation achieved longer-term pain relief with a more minimal incidence rate of skin numbness than did RFT. Further randomized controlled trials should be conducted to solidify coblation’s clinical superiority to RFT as a PHN treatment.

KEY WORDS: Post-herpetic neuralgia (PHN), neuropathic pain, thermocoagulation, plasms-mediated technology, clinical outcomes