Refractory Cerebrospinal Fluid Leak After Chiari I Decompression Followed by Resolution After Prolonged Lumbar Drainage: A Case Report

Chiari malformation type I (CMI) is characterized by descent of the cerebellar tonsils below the foramen magnum and is frequently associated with altered cerebrospinal fluid (CSF) flow.Posterior fossa decompression (PFD) is the standard treatment, and CSF leakage is one of its most common complications.A 21-year-old woman presented with a two-year history of progressive holocranial headache, dizziness, gait instability, and paresthesias.Magnetic resonance imaging (MRI) revealed 15 mm of cerebellar tonsillar descent.She underwent PFD with duraplasty and C1 posterior arch resection.Postoperatively, she developed a refractory CSF leak despite wound resuturing and subsequent dural reinforcement using a fascia lata graft.A lumbar drain was subsequently placed and maintained for 21 days, resulting in complete resolution of the leak without further surgery or infectious or drain-related complications.Her neurological deficits and headache had resolved by the one-month follow-up, and she remained asymptomatic without recurrence at three and six months.No validated algorithm defines the optimal timing or duration of lumbar drainage, and reported drainage durations rarely exceed two weeks.This single, hypothesis-generating observation suggests that prolonged lumbar drainage guided by drain output may be considered a salvage strategy in highly selected, closely monitored patients, although its safety beyond this duration remains unestablished.