Immediate Complications Associated with High Flow Cerebrospinal Fluid Egress during Endoscopic Endonasal Skull Base Surgery

Introduction: Endoscopic expanded endonasal approaches (EEAs) to the skull base are increasingly being utilized to address a variety of skull base pathologies. Postoperative cerebrospinal fluid (CSF) leakage from the large skull base defects created with this approach has been well described as one of the most common complications of EEAs. Though meningitis is the most common serious consequence of persistent CSF leakage after skull base EEA surgery, authors have reported cases of associated formation of delayed subdural hematoma and tension pneumocephalus from approximately one week to three months postoperatively. However, there have been no reports of immediate complications of high volume CSF leakage from EEA skull base surgery. We present two cases of EEA skull base surgery in which complications of rapid, large-volume CSF egress from the defects created were detected in the immediate postoperative period and propose preventive measures to reduce the likelihood of these immediate complications.

Case Reports: Case 1: An 80-year-old woman underwent an EEA for resection of a 3 cm diameter sellar/suprasellar hemorrhagic mass. Substantial CSF egress was noted during the procedure, as the tumor had eroded through the diaphragm sellae (obliterating it in the process) and into the suprasellar subarachnoid space. Intraoperative somatosensory evoked potentials demonstrated decreased responses from the left side of the body after CSF loss. Intraoperative computed tomography of the head (CTH) was obtained, revealing a large acute right hemispheric subdural hematoma, which we evacuated in standard fashion under the same anesthesia.

Case 2: A 74-year-old man presented having previously underwent an EEA for resection of a clival chordoma, during which the nasoseptal mucosa was rendered unfit for skull base repair and substantial residual mass was left behind. We performed a transclival EEA with complete resection of this mass, creating a significant clival dural defect. We harvested a vascularized temporoparietal fascia flap (TFF) for the skull base repair. Approximately 120 minutes were required for the TFF harvest, during which time we noted substantial CSF loss from the defect. An immediate postoperative CTH demonstrated tension pneumocephalus and bilateral cerebellar hemispheric intraparenchymal hemorrhage. The tension pneumocephalus was relieved emergently via a right frontal burr hole.

Discussion: Much attention has been paid to long term CSF leak complications in skull base surgery both before and after the advent and widespread implementation of EEAs. Consequently, much attention has further been paid to reducing the incidence of postoperative CSF leakage by using increasingly complex multilayered repairs and ultimately vascularized pedicled mucoperiosteal flaps to avoid long-term complications. However, the cases presented here highlight immediate complications related to relatively rapid large volume CSF egress during EEA skull base surgery and suggest the need for retardation of CSF loss and “early” postoperative imaging and clinical watchfulness. Based on our experience, we feel that patients undergoing prolonged EEA skull base surgery with high volume CSF leakage may be better managed with intraoperative maneuvers to impede CSF loss (such as with temporary collagen matrix inlay grafts or temporarily inlaid cottonoid patties) as well as planned immediate postoperative imaging.