Delayed extensive lumbar sub-dural effusion following discectomy - Clinical imaging and case report.

Incidental durotomy during lumbar spine surgery is a commonly reported complication. Those presenting with cerebrospinal fluid (CSF) leak are usually recognized and repaired intraoperatively. In some circumstances, it may either be unrecognised or occur as a delayed complication. Such delayed occurrences cannot be predicted and its management remain a challenge to the surgeon, especially when it presents as a subdural effusion. We report a 55-year-old man who underwent mini open lumbar discectomy through left side for a prolapsed L4-L5 disc. Recurrent worsening radicular symptoms along with a palpable cystic swelling at the previous surgical site became eminent, three months after surgery. MRI revealed distinctive anterior translation of all rootlets with subdural fluid collection posterior to it, within a normally placed dura, extending from L1 to L5 levels. A concomitant pseudomeningocele with a fistulous tract was also evident. Draining of pseudomeningocele with widening of previous laminotomies revealed a dural defect of less than 0.5 cms that prompted the CSF leak. Subdural effusion was drained following which the defect was repaired with inlay polyester urethane dural substitute patch and augmented with fibrin sealant. Symptoms regressed and follow up was uneventful. Occurrence of sub-dural effusion in lumbar spine is inevitably uncommon. We advise to suspect this condition in patients with recurrent symptoms following satisfactory lumbar decompression surgeries. Recognising this condition, followed by appropriate drainage of subdural effusion and direct repair of the dural defect is highly recommended for a better prognosis.