Minimum-Invasive and Endoscopic Surgery of Skull Base Tumors: Use of Extracranial Approaches

A.N. Shkarubo

(Burdenko Research Institute of Neurosurgery, Moscow)

Introduction. Tumors of anterior segments of a skull base are removed with applying different transcranial approaches, including transcranial-transfacial ones. Extracranial accesses (transsphenoidal and/or transoral), based on use of natural anatomic cavities, can be considered to be minimum-invasive. A problem of deep and narrow wound has been solved by introduction of intraoperative endoscopic control, which is a new and prospective technology in neurosurgery.

Materials and Methods. We operated 204 cases, aged 8-68. Original patented instruments, devices and methods of surgical treatment were used. A transsphenoidal approach was made in 89 cases under intraoperative endoscopic control. They had the following pathology: pituitary adenomas 68 (endosellar localization -5, endo-extrasellar localization 63), endo-extrasellar craniopharyngiomas 11, skull base chordomas 5, other skull base tumors 5. Rigid endoscopes and fibroendoscopes were used for ensuring endoscopic control. A transoral approach was performed in 12 cases with chordomas; 3 patients with chordomas were operated with use of a combined (transnasal and transoral) access. Transoral and combined approaches did not demand endoscopic control due to peculiarities of neoplasms spread. We applied instruments, devices and methods, patented by us, in all the cases. Tumor removal was followed by a hermetic closure and plasty of a skull base in 19 cases. They were made in compliance with patented methods, which allowed to prevent postoperative liquorrhea.

Results and Discussion. Indications and contraindications for transsphenoidal and transoral accesses, as well as their combination, were determined.

Endoscopic technique, used in a transsphenoidal approach, makes it possible:

- To visualize tumor tissue of supra-laterosellar localization, which is not visible in a straightforward view of an operative field, obtained with the help of a microscope.

- To visualize intact tissue of the pituitary body and its relationships with a tumor; to reduce operative trauma of the hypophysis (there were two cases with transient diabetes insipidus); to minimize probable development of intraoperative liquorrhea (it was present in 5 cases (4.8%); there was no postoperative liquorrhea); to achieve higher quality of surgical treatment (vision improvement and its absence were watched in 86.3% and 11.8% of cases respectively; these indices in pituitary adenomas were 90.2% and 9.8%).

- To increase operation efficacy (radical, i.e. total and subtotal, removal was performed in 96.1% of cases). Tumor recurrences were observed in 6 patients (5.7%) during 1.5-2 years (pituitary adenoma 1, craniopharyngiomas - 2, chordomas 3).

One patient (0.96%) with giant pituitary adenoma died.

Use of transoral and combined approaches allowed to achieve radical removal (total and subtotal) in 40% of cases. The majority of cases were characterized by regression of clinical symptoms. Two cases developed intraoperative liquorrhea. There was no postoperative liquorrhea. Two patients were reoperated in 1.5-2 years.

Conclusion. Use of endoscopic control in extracranial surgery of skull base tumors and its combination with original methods of plasty allow to improve treatment results and to reduce a rate of postoperative complications to a considerable extent.