Preoperative laminagraphic evaluation of the sphenoid sinus for transsphenoidal surgery.

In recent years the transethmoidal and transnasal approaches to the pituitary gland have become increasingly popular. In each case, detailed preoperative analysis of the anatomy of the sphenoid sinus and its boundaries is crucial in facilitating entry to the pituitary fossa and in reducing intraoperative complications. Certain operative difficulties and complications are the result of the marked variability in the anatomy of the sphenoid bone and its sinus. These include: loss of orientation within a capacious sinus; perforation of the carotid artery or cavernous sinus; injury to the optic nerve or ophthalmic artery; and violation of the subarachnoid space with resultant pneumocephalus or cerebrospinal fluid rhinorrhea. Pneumatization develops originally within the presphenoid, beginning anteriorly and proceeding posteriorly. Around the time of puberty the pneumatization usually penetrates up to the spheno-occipital synchondrosis. Dense bony septa remain within the sinus along the plane of fusion of the various sphenoidal segments. Preoperative laminagraphy of these ridges and septa is extremely helpful in planning the safest and most direct route to the sella. Laminagraphy is preferable to routine skull films because the septal detail is unobscured by overlying facial structures. Pleuridirectional laminagraphic motion (circular or hypocycloidal) is preferred to linear motion because of the clarity and detail that they provide.