Midline Shift Induced by the Drainage of Cerebrospinal Fluid in Three Patients With External Decompression.

It is not rare that progressive hydrocephalus worsens clinical conditions in a patient with external decompression and drainage or shunt surgery is required. However, spinal drainage or shunt surgeries potentially carry a risk of causing paradoxical herniation in a patient with decompressive craniectomy, particularly in a comatose case with wide craniectomy. Careful and strict observations are necessary for such patients. In our three comatose cases with craniectomy, paradoxical herniation occurred due to excessive drainage after 5-7 days of shunt surgery and lumbar drainage, although the drainage pressure was set at more than 10 cmHO. Fortunately, in the three cases, the herniation improved within a few days after the drain was clamped and the bed was flattened. However, the Trendelenburg position and epidural blood patch might be necessary if paradoxical herniation occurs acutely after lumbar puncture or drainage because delayed resolution can be fatal in the herniation.