Case report: cauda equina syndrome associated with an interspinous device.

BACKGROUND: Although postoperative spinal epidural hematoma (SEH) is not uncommon, hematomas that require surgery are rare. Cauda equina syndrome (CES) may be associated with postoperative SEH. In these cases, early recognition and emergency decompression can prevent further damage and better neurologic recovery. CASE DESCRIPTION: A 41-year-old man underwent two-level discectomy with insertion of an interspinous spacer at L3-4 and L4-5 because of low back pain and radiculopathy. Eight hours after the operation, the patient developed CES. MRI revealed SEH compressing posteriorly at the L3-4 level. On emergency decompression and hematoma evacuation, the interspinous spacer had obstructed the laminotomy site at L3-4 completely, blocking drainage to the drain. The patient experienced complete neurologic recovery by 2 months followup. LITERATURE REVIEW: Many studies report risk factors for SEH. However, postoperative SEH can also be encountered in patients without these risks. One study reported a critical ratio (preoperative versus postoperative cross-sectional area) correlated with postoperative symptoms, especially in those with CES. The propensity to develop CES is likely dependent on a number of patient-specific factors. CLINICAL RELEVANCE: Surgeons should be aware that patients without risk factors may develop acute CES. Wider laminotomy (larger than half of the device size) may help to prevent this complication when one uses the compressible type of device, especially in patients with relatively small lamina.