Preparation for Surgery for Infratentorial Hemangioblastomas in Children
Indications for Surgery
Presence of clinical signs and/or symptoms
Enlarging tumor on serial MRI
Associated complications: Hemorrhage, overcrowding of the foramen magnum, upward cerebellar herniation, or syringobulbia.
Intensive preoperative steroid therapy: Steroids can often allow patients to undergo surgical tumor resection alone without preoperative ventriculostomy placement in the setting of accompanying hydrocephalus.
Preoperative CSF diversion: CSF is diverted preoperatively only when an immediate decrease in ICP is required. Endoscopic third ventriculostomy (ETV) or external ventricular drainage (EVD) are currently preferred to CSF shunting (almost abandoned).
Preoperative embolization: Preoperative embolization can be used to reduce the risk of intraoperative bleeding. Criteria for embolization are the presumably difficult control of the afferent arteries and the presence of redundant cerebellar arterial supply. Embolization has the risk of ischemic or acute bleeding complications, so it is not routinely performed (6, 36).
Monitoring: Monitoring includes heart rate, invasive arterial blood pressure, central venous pressure, pulse oximetry, spirometry, end-tidal carbon dioxide, urine output, peripheral and core temperature, acid/base status (serial determinations), blood loss, and clotting function (serial determinations).
Hypothermia and/or induced hypotension: These techniques can be used in selected cases, namely, very large hemangioblastomas with bilateral cerebellar artery supply or significant intraoperative bleeding.
Standard equipment: Mayfield-like head holder (or horseshoe in infants and young children), microscope, cavitron ultrasonic aspirator, hemostatic agents).
Intraoperative guidance: Intraoperative ultrasound or neuronavigation system can be useful for localizing small and/or deep hemangioblastomas.
Intraoperative neurophysiological monitoring: SSEPs, MEPs, and cranial nerve monitoring can be helpful for surgery on hemangioblastomas involving the brainstem or the cervicomedullary junction.
Laser: Photocoagulating lasers can be used on large and vascularized hemangioblastomas.