Unilateral biportal endoscopic decompression for thoracic intraspinal gout with ossified ligamentum flavum: a case report and literature review.

Objective: Intraspinal tophaceous gout is rare but may cause severe neurological deficits when it compresses the spinal cord. Thoracic spinal stenosis due to ossification of the ligamentum flavum (OLF) is an additional, common dorsal compressive pathology. We report a patient with thoracic spinal canal stenosis due to OLF with concomitant epidural tophaceous gout, successfully treated using unilateral biportal endoscopy (UBE) combined with percutaneous pedicle screw fixation. Clinical presentation and intervention: A 50-year-old man with a 4-year history of gout and multiple peripheral tophi presented with a 2-year history of back pain that worsened over 2 weeks, accompanied by bilateral lower-limb pain, numbness, and marked weakness (lower-limb strength grade 2). Preoperative imaging demonstrated severe thoracic canal stenosis at T10-T11 due to OLF and new compression fractures at T8 and T10. Laboratory tests revealed leukocytosis, elevated ESR and CRP, and hyperuricemia. The patient underwent UBE-assisted decompression with resection of the OLF at T10-T11, followed by percutaneous pedicle screw fixation at T7-T9 and T11-T12. Intraoperatively, abundant chalky-white tophaceous material was identified in the epidural space and confirmed histologically as monosodium urate deposits with granulomatous inflammation. His symptoms gradually resolved, muscle strength improved, and he achieved good functional recovery one year post-operatively. Conclusion: This case suggests that UBE may be a precise minimally invasive option for selected patients with thoracic intraspinal gout and underscores the necessity of multidisciplinary care and long-term urate-lowering therapy.