Endocrinology: hormones, adenoma hypophysis, pituitary tumor

Endovideomonitoring in Transsphenoidal Surgery of Pituitary Neoplasms

V.Yu. Cherebillo, V.R. Gofman, A.V. Polezhaev, V.A. Manukovsky

Chair of Neurosurgery, Medicomilitary Academy, Saint Petersburg, Russia

Surgical Technique

A presellar type of pneumatization was less favorable, as a vertical size of trephination defect was reliably smaller (10mm on the average). It reduced an angle of operative activity up to 16^o. Thus, it made orientation in adjacent structures and manipulations of a surgeon more difficult.

In this situation it was expedient to widen a sphenoid opening for obtaining the maximum bone defect. It was done with spoons for bones, Luk's and Hajek's forceps. The endoscope was introduced into the sinus cavity after performing sphenoidotomy (15x20mm in a sellar type of the sinus pneumatization) and verifying a position of instruments with the help of lateral fluoroscopy. These manipulations were a necessary condition for getting a panoramic view of the sinus cavity, as well as for unimpeded coaxial insertion of other instruments into it.

However, it should be emphasized, that sphenoidotomy with a height of more than 8mm could not be performed in 7-8% of cases. It was caused by an extremely small size of the sinus anterior wall. It was possible to identify main landmarks during examination of the sinus cavity, but coaxial insertion of microinstruments and the endoscope was technically unfeasible. A panoramic examination of the sinus, fundus and the saddle was carried out after taking the instruments out of an operative wound. Thus, it was a staged endoscopic control.

It should be noted, that quality of visual examination of the sphenoid sinus cavity was dependent on intensity of bleeding from adjacent anatomic structures in general, and its mucous membrane in particular. Accumulation of blood in the cavity of the Bumenbach's clivus and lower parts of convexity of the saddle fundus hampered visualization and demanded non-stop aspiration of clots with a microscopic suction unit. When a mucous membrane was almost intact and bleeding was minimum, quality of endoscopic visualization was very high. If mucosa, lining the sinus internal surface, was damaged considerably, quick accumulation of blood in the sinus cavity and, as a result, a dirty optic system made examination of an operative field to be a real problem. Total removal of mucosa in case of its damage and bleeding allowed to reduce an effect of this unfavorable factor on an operation course. Its removal with microforceps ensured a "dry" operative field in the majority of cases and allowed to choose a place of trephination of the saddle fundus without any difficulty.

Sometimes endoscopic examination after sphenoidotomy was indicative of opening only of the right or left half of the sinus. A surgeon, lacking due experience or qualification, can think by mistake, that he has performed a full-value approach; it will result in loss of orientation and surgical errors. As for our research, detailed endoscopic examination of the sinus half allowed to visualize convexities of ICA, optic and V₂ canals, opto-carotid recesses only on one side. Convexities of the saddle fundus, planum sphenoidale and the cavity of Blumenbach's clivus were visualized partially. It was impossible to reveal a median plane, passing through the saddle fundus, on the basis of these landmarks. The endoscope permitted to determine peculiarities of localization of the intersinus septum more precisely, to estimate dimensions of an opened segment of the sinus and presence of additional septa or crests.

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