Midline Skull Base Surgery by Paolo Cappabianca Luigi Maria Cavallo Oreste de Divitiis & Felice Esposito

Author:Paolo Cappabianca, Luigi Maria Cavallo, Oreste de Divitiis & Felice Esposito
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

16.2.3 Authors’ Preferred Surgical Technique

Our surgical technique is similar to that described by Kirollos et al. [11]. Under general anesthesia, a frontal burr hole is drilled 3–4 cm from the midline (usually on the right side, or on the larger side, in case of asymmetrical ventricular dilatation) and on the coronal suture. The ideal position of the entry point and the best trajectory is selected on the basis of preoperative MR imaging. Neuronavigation is useful but usually not mandatory in standard cases, unless the ventricular system is small. The lateral ventricle is tapped, and the endoscope is directed toward the foramen of Monro, where the dome of the cyst is usually protruding into the third ventricle and comes into view. A fenestration is made between the cyst and the ventricle with various techniques, and we prefer to use Tulium LASER coagulation and scissors. Wide fenestration, at least 10 mm in diameter, is achieved, with coagulation of the apical portion of the cyst and removal of the cyst wall if possible. The cyst is then entered with the endoscope to visualize the basal wall of the third ventricle and the position of the basilar artery (inside the cyst, or outside the cyst, pushed toward the brain stem). It is usually possible to observe all the anatomical structures around the interpeduncular cistern through the thin inner layer of the arachnoid cyst, such as the basilar artery, internal carotid artery, posterior communicating arteries, pituitary stalk, optic chiasm, and third cranial nerves. Several openings into the basal prepontine cistern should be created, usually between basilar artery and third cranial nerves from both sides. The openings can be done using a probe without the application of any current and enlarged with balloon catheters. The endoscope is then advanced through the fenestration to visualize the neurovascular structures in the basal cisterns and to ensure the creation of adequate communication between the cyst and the subarachnoid space.

In the rare cases in which suprasellar cyst expand laterally toward the temporal fossa, the cyst can be approached directly through a temporal burr hole, like middle fossa cyst. Once inside the cyst with the endoscope, a cyst-cisternostomy can be performed in standard fashion, trying to make multiple perforations, on both sides of the basilar artery (Figs. 16.2a, b and 16.3a–j).

Fig. 16.2(a) Type 1 suprasellar cyst, bulging into the third ventricle and occluding both foramina of Monro and the inlet of the aqueduct. (b) Surgical trajectory (arrows) for ventriculocystostomy and cyst-cisternostomy through a coronal burr hole

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