Ultrasound-Guided Sacral Erector Spinae Plane Block for Anorectal Surgery in a Patient with POEMS Syndrome: A Case Study and Literature Review

Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome is a rare multisystem paraneoplastic disorder. The syndrome presents unique perioperative challenges, including sclerotic bone changes that may preclude conventional neuraxial techniques. The ultrasound-guided sacral erector spinae plane (SESP) block represents a novel interfacial plane block that offers an alternative approach for sacral region analgesia. We describe a 58-year-old man with POEMS syndrome who presented with an acute perianal abscess requiring surgical drainage. The patient exhibited multiple high-risk features: sacrococcygeal sclerosis preventing identification of the sacral hiatus, severe hyperkalemia (6.54 mmol/L), stage 3 chronic kidney disease, pericardial effusion, and previous ischemic stroke. These comorbidities rendered traditional caudal epidural block contraindicated and general anesthesia high risk. Under ultrasound guidance, a single-shot SESP block was performed at the S3–S4 level using 25 mL of 0.2% ropivacaine with 25 µg dexmedetomidine. The block provided complete intraoperative analgesia (visual analog scale [VAS] score of 0) and effective postoperative pain control (VAS score <2 for 24 hours), facilitating successful surgery and discharge on postoperative day 1. This case demonstrates that the SESP block is a feasible and effective alternative for patients with complex conditions such as POEMS syndrome, where neuraxial techniques are anatomically precluded or clinically contraindicated. Based on this experience and supporting literature, the SESP block warrants consideration as a valuable component of multimodal analgesic strategies for anorectal and pelvic floor surgery, particularly in high-risk patients with challenging anatomy or significant comorbidities.