Thoracic paravertebral hematoma following ultrasound-guided block despite compliance with anticoagulation guidelines: A case report

Thoracic paravertebral block (TPVB) is a reliable and commonly used regional anesthesia technique for thoracic surgery that offers effective somatic and visceral analgesia. Although considered safe, TPVB carries a rare risk of bleeding complications owing to its anatomical proximity to the pleura, intercostal vessels, and noncompressible vascular structures. We present the case of a 72-year-old male undergoing elective left lower lobectomy and single-injection ultrasound-guided TPVB. The procedure followed the current antithrombotic guidelines, demonstrated clear sonoanatomical landmarks, and showed no technical difficulties or aspiration of blood. Thoracoscopic inspection revealed a localized asymptomatic paravertebral hematoma. The patient remained hemodynamically stable and required no intervention. This report highlights that paravertebral hematoma may occur despite adherence to current antithrombotic guidelines and technically successful ultrasound-guided TPVB. Possible mechanisms include microvascular trauma, anatomical variability, pleurovascular proximity in lean individuals, and limitations of two-dimensional imaging. Preventive measures should extend beyond ultrasound guidance to include Color Doppler imaging, gentle injection techniques, hydrodissection, and awareness of patient-specific risk factors. Postprocedural monitoring and individualized planning are essential for early recognition and safe management. • Thoracic paravertebral block is generally safe under ultrasound guidance; however, rare hematoma formations may still occur. • Hematomas may arise even when anticoagulation protocols and procedural techniques fully comply with guidelines. • Microvascular trauma, anatomical variation, or brief needle tip misvisualization can contribute to bleeding. • Risk may be reduced by using Color Doppler and hydrodissection, as well as by avoiding high-risk needle paths. • Careful patient selection and close postoperative monitoring are crucial, especially in lean or anatomically complex patients.