Minimally invasive approaches to aneurysms of the anterior circulation: selection criteria and clinical outcomes.

Over the last few decades, cerebrovascular surgery has gravitated towards a minimally invasive philosophy without compromising the foundational principles of patient safety and surgical efficacy. Enhanced radiosurveillance modalities and increased average life expectancy have resulted in an increased reported incidence of intracranial aneurysms. Although endovascular therapies have gained popularity in the recent years, microsurgical clipping continues to be of value in the management of these aneurysms owing to its superior occlusion rates, applicability to complex aneurysms and reduced retreatment rates. The concept of keyhole transcranial procedures has advanced the field significantly leading to decreased postoperative neurological morbidity and quicker recovery. The main keyhole neurosurgical approaches include the supraorbital craniotomy (SOC), lateral supraorbital craniotomy (LSOC), mini-pterional craniotomy (MPTC), mini-orbitozygomatic craniotomy and the mini anterior interhemispheric approach (MAIA). As these minimally invasive approaches can have an inherent limitation of a narrow viewing angle and low regional illumination, the use of endoscopic assistance in such procedures is being popularized. Neuroendoscopy can aid in the visualization of hidden neurovascular structures and inspection of the parent arterial segment without undue retraction of the lesion. This review focuses on the historical progression of the surgical management of intracranial aneurysms, the technical details of various minimally invasive approaches, patient selection and clinical outcomes of the anterior circulation aneurysms and useful tenets to avoid complications during these procedures. Meticulous preoperative planning to understand the patient's vascular anatomy, the orientation and relationship of the aneurysm to adjacent structures, use of neuronavigation guidance and endoscopic assistance if needed can lead to an optimal surgical outcome while minimizing neurological morbidity and mortality.