The efficacy of serratus posterior superior intercostal plane block performed under ultrasound guidance in thoracic postherpetic neuralgia: a retrospective cohort study

Abstract Background Postherpetic neuralgia (PHN) is a neuropathic pain syndrome that can be resistant to traditional therapies and severely impairs quality of life. The serratus posterior superior intercostal plane block (SPSIPB) is a recently described regional anesthesia technique conducted under ultrasound guidance, thought to provide analgesia for thoracic neuropathic pain. This research analyzed the effectiveness and safety of SPSIPB in patients with thoracic PHN. Methods Thirty-four thoracic PHN patients who underwent SPSIPB between June 2023 and February 2025 were retrospectively evaluated. Pain intensity was evaluated utilizing the Numerical Rating Scale (NRS-11), neuropathic pain symptoms using the Douleur Neuropathique 4 (DN4) questionnaire, and quality of life using the 12-item Short Form Health Survey (SF-12). Measurements were taken before the procedure and at 1 month and 3 months post-procedure. Results Thirty-four patients were included. Mean patient age was 68.4 ± 7.1. Among all patients, 50% were female. The NRS-11 scores decreased from 7.6 ± 1.1 before the procedure to 2.8 ± 1.3 at 3 months (p < 0.001). The DN4 scores also decreased from 6.4 ± 1.0 before the procedure to 3.1 ± 1.2 at 3 months after the procedure (p < 0.001). Significant increases were observed in both the physical and mental component scores of the SF-12 (p < 0.001). No severe complications were encountered. Conclusion SPSIPB administered under ultrasound guidance is associated with a reduction in pain intensity and an improvement in quality of life in patients with thoracic postherpetic neuralgia. However, given the study’s retrospective design and the absence of a control group, these outcomes should not be considered indicative of a causal effect; instead, they should be interpreted as hypothesis-generating. Prospective, randomized controlled trials are needed to demonstrate the efficacy of SPSIPB and its comparative benefits relative to other interventions. Trial registration This retrospective single-center study was conducted in accordance with the Helsinki Declaration. It was registered on clinicaltrials.gov (NCT07067892).