Neuroendoscopic Management of Intraparenchymal Lesions

Abstract

The ability of endoscopes to drive illumination and vision into the area of interest has led to the possibility of working into body cavities through reduced access. In this way, managing lesions inside solid tissues obligates the creation of a working space – just a trajectory where light, vision, and surgical tools come into the working site. The direction and the small diameter of this corridor are critical to minimize brain damage.

The concept of a keyhole craniotomy combined with a selected trajectory can enable the approach of intraparenchymal lesions. However, the decision to use endoscopy must be individualized based on the patient, site, and characteristics of the lesion.

We routinely use neuroendoscopy, assisted by neuronavigation and at times ultrasound, to remove intraparenchymal brain lesions. The approach is planned, determining an ideal entry point and a straight trajectory to the target. Fiber tracking can be very helpful in order to avoid important projection fibers along the trajectory.

A 1.2 cm trepanation is performed, which can be extended to an elliptical shape in order to facilitate some lateral movement of the sheath and endoscope. A purpose-designed sheath with its internal obturator is then introduced progressively into the brain parenchyma, with or without the orientation of a neuronavigation system, depending on each case. Once in position, the obturator is removed and the endoscope is introduced to confirm the correct position. In most cases clear differentiation of normal and pathological tissue interface can be observed.

Resection is then performed introducing instruments through the sheath, in parallel to the endoscope. Multiple instruments can be used alone or in combination (suction tubes, tumor forceps, microscissors, monopolar or bipolar coagulation) in order to perform resection of the lesion. Partial or total removal of the lesion may be achieved, depending on its nature and the proposed objectives. Once the intended resection is completed, the sheath is removed progressively with constant endoscopic visualization so that eventual bleeding at the pathway walls can be observed and controlled.

The experience, taken from 81 selected cases, including primary and secondary brain tumors, cavernous angiomas, intraparenchymal hematomas, cerebellar infarctions, sellar tumors, and brain abscess, proves the technique as an accurate and safe procedure. Except for a transient third nerve paresis in a patient with mesial temporal metastasis, no additional neurological deficit was produced in this series of patients.

The patients treated with this method had a shorter ICU and hospital stay when compared to similar cases treated by microsurgical technique by the same group of surgeons.