“Double-Window” Approach to the Giant Pituitary Adenomas: The Importance of Skull Base Dissection for Further Reconstructive Purposes

 

Giant pituitary adenomas are one of the most challenging issues of neurosurgery. Extended endoscopic endonasal approach has become desirable route due to its advantages. An issue that needs to be pointed out is, CSF leakage and fistula formation after such a large-scale skull base defect. We want to call attention to the opening stage, to show how reconstruction part will take place.

At the beginning wide, pedicled, nasoseptal Haddad flap is prepared. After dissection of the mucosa, two bony windows, which are 15 mm in width and 20 mm in length, are opened in the sellar floor and planum sphenoidale. We keep the posterior part of planum sphenoidale for the further reconstructive purposes. The remaining part of planum sphenoidale will be supportive during reconstructive stage and will prevent the fascia graft from slipping and prolapse of the rectus gyrus through such a large defect at the cranial base. Considering tumor tissue bigger than 5 cm and an opening of such big defect at the cranial base is estimated to cause at least CSF fistula.

Two different fascia lata grafts are inserted, the first fat graft on the sellar region, and the second on the defect in the planum, with two separate dimensions of ∼25 mm as an inlay. As an onlay, same graft is used as a single large piece to buttress both defects. Then vascularized nasoseptal flap, which was taken at the beginning of the operation, is placed.

We believe that it is beneficial to open a few corridors to prevent CSF fistula formation in the postoperative period in expanded endoscopic transtuberculum, transplanum approaches, especially in giant pituitary adenomas, which occupy a significant area in the skull base.