Anesthesia for Minimally Invasive Neurosurgical Procedures in Children

Since the inception of the specialty of neurosurgery, conventional teaching was that “bigger opening is better.” This statement was based on the principle that a larger opening could allow room for the swollen brain to expand adequately, resulting in lower intracranial pressure (ICP) and reducing the potential for retractor-induced ischemia to normal brain tissue. Adverse brain conditions could also be encountered due to inhalational anesthesia, vasodilatory effects of medications used to regulate blood pressure, and awkward patient positioning leading to brain swelling. Imaging techniques were not available during the early years of neurosurgery, and a large craniectomy allowed for easier localization of the lesion, easier control of bleeding, and room to perform resective surgery in cases of refractory brain bulge. Morbidity and mortality of traditional neurosurgery due to large craniotomies and subsequent brain damage during surgery were well-recognized a century ago. Over the last three decades, advancements in technology have eliminated most difficulties encountered by earlier generations of neurosurgeons. Recent imaging modalities provide accuracy within a few millimeters, and stereotactic guidance has increased the accuracy to the submillimeter level. Neuronavigation tools allow the surgeon to map the perfect trajectory to precisely target lesions while causing minimal damage to eloquent areas of the brain. Advanced micro-equipment and endoscopes allow access to deeper tissues with minimal handling of adjacent brain tissues. Advancement in anesthesia techniques and a better understanding of neurophysiology and neuropharmacology have led to improved control over ICP in the perioperative setting. Facilitation of minimally invasive neurosurgery requires preoperative planning with investigations such as computed tomography (CT), magnetic resonance imaging (MRI), and intraoperative aids like neuroendoscope (using small burr hole/craniotomy), neuronavigation (image guidance system), or the use of robotic aided surgery. This chapter details the nunaces of anesthesia for minimally invasive neurosurgery.