DELAYED INTRACRANIAL HEMORRHAGE IN CHILDREN AFTER SUBOCCIPITAL CRANIECTOMY

OBJECTIVE. The purpose of this study was to report the clinical and im aging findings of seven children who developed extraaxial, intracrania l hemorrhage 3-12 years after suboccipital craniectomy for neoplasia. We attempt to explain the hemorrhages based on a previously reported h ypothesis of neomembrane formation associated with dural substitutes u sed to repair large dural defects. MATERIALS AND METHODS. Clinical cha rts (seven patients), surgical and pathologic findings (four patients) , and imaging studies (CT scans and MR images in four; CT scans, MR im ages, and angiograms in one; and CT scans only in two patients) were r eviewed retrospectively. Hemorrhage occurred 3-12 years after suboccip ital craniectomy for tumor (ependymoma in two, medulloblastoma in thre e, astrocytoma in one, and ganglioglioma in one). Silastic dural subst itute was used to repair the surgical wound in six cases and human dur al graft in one case. Hematomas were spontaneous in four and occurred after minor head trauma in three. Four patients had multiple hemorrhag ic episodes. RESULTS. CT scans and MR images showed acute extraaxial h emorrhages at the craniectomy site without contiguous residual or recu rrent neoplasia in all patients. No intraaxial or intratumoral hemorrh age was detected. Findings on cerebral angiograms in one patient were normal. Four patients underwent surgical exploration of the hematoma a nd craniectomy site; no macroscopic source of bleeding was detected. T he hematomas were not associated with recurrent tumor pathologically. CONCLUSION. Delayed, benign extraaxial hematomas may occur in children who have undergone craniectomy for tumors of the posterior fossa and have had dural substitute used to repair large defects. Fragile vessel s associated with neomembranes have been proposed as the source of hem orrhage.