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

The cavity of Blumenbach's clivus was localized just under convexity of the saddle fundus and served a posterior wall of the sphenoid sinus. Its size depended on a type of the sinus structure. The greatest (1.2mm on the average) and smallest (0.5mm on the average) depth of this cavity corresponded to sellar and presellar types of pneumatization. The convexity of the saddle fundus was marked to the smallest degree in a presellar type. This convexity had clear contours and was marked to the utmost in a sellar type of pneumatization.

The next endoscopic landmark was twin convexities of internal carotid arteries, which could not be seen only in 5% of cases. When a butt end of the endoscope was placed at the level of sphenoidotomy, a panoramic examination of the sinus allowed to visualize these structures in the majority of cases. An average distance between a place of trephination of the sinus anterior wall and the saddle fundus was 16.9mm. Such a position of the endoscope allowed to carry out full-value examination of the sinus cavity and to determine an axis of its subsequent route.
 

The endoscope introduction and placement of its butt end at a distance of 4-5mm from the saddle fundus made it possible to examine ICA convexities in detail. It should be noted, that ICA convexities differed, depending on a type of the sphenoid sinus pneumatization. They were marked poorly in a presellar type; thus, their identification was less frequent.
 

Optic canals formed twin convexities in a cavity of the sphenoid sinus and were visualized in the majority of cases. We failed to identify them in 2.5% of patients. Convexities of optic canals were visualized in the upper part of the lateral wall of the sphenoid sinus. They were localized on both sides of the saddle fundus above ICA convexities. The canal convexities looked like two symmetrical toruli. A depth of their penetration into the sinus cavity was dependent on a pneumatization type. A length of convexities of optic canals varied from 4.9 up to 11.1mm (7.1mm on the average).
 

Convexities of ICA and optic canal formed an opto-carotid recess in an upper lateral angle of the sphenoid sinus. It looked like an excavation between an upper part of the ICA presellar segment and a lateral part of the optic canal convexity. It was limited by the saddle fundus medially.
 

Maxillary branches of the trigeminal nerve formed twin convexities in the cavity of the sphenoid sinus in 77% of cases. A convexity size was conditioned by a type of pneumatization of the sphenoid sinus.
 

It was found out, that a sellar type of pneumatization was the most convenient type both for performing an approach and carrying out endovideomonitoring. It allowed to use extensive sphenoidotomy (a height of 15mm). A maximum angle of operative activity (19^o on the average) was achieved in application of the endoscope with a diameter of 4.0-5.8mm and placing the optic system and microinstruments above each other in a vertical plane.

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REFERENCES

1. Apuzzo M.L.J., Heifetz M.D., Weiss M.H., Kurze T. Neurosurgical endoscopy using the side-viewing telescope // J. Neurosurg.- 1977.- Vol. 46, N 2.- P. 398-400.

2. Cawley C.M., Tindall G.T. New techniques in managing sellar pathologies through modifications of the traditional transsphenoidal approach // Crit. Rev. Neurosurg.- 1997.- Vol. 7, N 2 .- P. 115-122.

3. Gamea A., Fathi M., EL-Guindy A. The use of the rigid endoscope in transsphenoidal pituitary surgery // J. Laryngol. Otol.- 1994.- Vol. 108, N 1.- P. 19-22.

4. Guiot G. Transsphenoidal spproach in surgical treatment of pituitary adenomas: general principles and indications in nonfunctioning adenoma. In: Kohler P.O., Ross G.T. Diagnosis and treatment of pituitary tumors. Amsterdam: Exepta Medica, International Congress Series N 303.- 1973.- P. 159-178.

5. Hardy J. Transsphenoidal hypophysectomy: neurosurgical techniques // J. Neurosurg.- 1971.- Vol. 34.- P. 582-594.

6. Heilman C.B., Shucart W.A., Rebeiz E.E. Endoscopic sphenoidotomy approach to the sella // Neurosurgery.- 1997.- Vol. 41, N 3.- P. 602- 607.

7. Jankowski R., Auque J., Simon C. et al. Endoscopic pituitary tumor surgery // Laryngoscope.- 1992.- Vol.102, N 2.- P. 198-202.

8. Jho H.D., Carrau R.L., Ko Y., Daly M.A. Endoscopic pituitary surgery: an early experience // Surg. Neurol.- 1997.- Vol. 47, N 3.- P. 213-223.

9. Rodziewicz G.S., Kelley R.T., Kellman R.M., Smith M.V. Transnasal endoscopic surgery of the pituitary gland: technical note // Neurosurgery.- 1996.- Vol. 39, N 1.- P. 189 - 193