Adhesive arachnoiditis (AA) is a chronic inflammation inside the dura and remains one of the most challenging diseases. We describe a case of treatment-resistant extensive AA that offers insight into surgical treatment selection. The patient had a 2-year history of progressive spastic gait and was diagnosed with syringomyelia caused by extensive AA. Although syringe-subarachnoid and subarachnoid-subarachnoid shunting resulted in recurrence within a short period, syringo- peritoneal shunting improved the symptoms and there was no recurrence. This case suggests that syringo-peritoneal cerebrospinal fluid (CSF) shunt drainage, which has previously been considered a further step, may be a first-surgery option for extensive AA.