Discriminative role of inflammatory indices in clinical response to ganglion impar blockade: A retrospective cohort study.

Coccydynia is a chronic pain syndrome with a complex pathophysiology. While ganglion impar blockade (GIB) is an effective treatment, predictors of response are not well-established. This study aimed to evaluate whether hematologic inflammatory indices or coccygeal morphology could predict the clinical response to GIB in patients with chronic coccydynia. We retrospectively reviewed the records of 119 patients who underwent GIB. Demographics, pain characteristics, coccygeal morphology (Postacchini-Massobrio classification), and preprocedural indices were extracted from the medical records. The primary outcome at the 1-month follow-up was a response, defined as either a ≥50% reduction in the visual analog scale pain score or a global perceived effect (GPE) score ≥ 6. Hematologic indices and coccygeal morphology were analyzed to assess their ability to discriminate between responders and nonresponders at 1 month after GIB. The overall response rate was 62.2%, with a significantly higher rate observed in females compared to males (P = .02). Responders had significantly higher baseline platelet-to-lymphocyte ratio (PLR; P = .006) and systemic immune-inflammation index (SII; P = .023), whereas other indices did not differ. Receiver operating characteristic analysis showed moderate discrimination for PLR (area under the curve = 0.650) and SII (area under the curve = 0.621). While overall coccygeal morphology was not associated with response (P = .25), types III and V were significantly associated with a higher rate of nonresponse (P = .048). GIB is an effective treatment for chronic coccydynia. Pre-procedural PLR and SII may serve as accessible biomarkers to identify patients more likely to benefit, while coccygeal types III and V may be associated with poorer outcomes.