gms | German Medical Science

Objective: Infiltration of the cavernous sinus is a common finding responsible for incomplete removal of pituitary tumors. Intraoperative visualization of parasellar structures is difficult despite advances in microsurgical and endoscopic technique. We describe the use of intraoperative direct contact ultrasound (US) in pituitary surgery in a large series of pituitary tumors.

Method: Out of 260 consecutive cases within 5 years in 126 (49%) microsurgical direct transnasal pituitary operations for pituitary macroadenomas (N=119; 78 non-secreting, 23 acromegaly, 8 prolactinomas, 5 Cushing's disease, 5 TSH-secreting; 18 recurrent adenomas; 15–71 mm in diameter), 3 meningiomas, 1 metastasis, and 2 Rathke's cleft cysts (61 male, 55 female; age 22–82 years), a side fire ultrasound-probe (B-mode frequency 4–13 MHz, linear field of view 10 mm, penetration 20 mm, colour coded flow mode 6 MHz; diameters of probe 17.6 × 6.9 × 9.4 mm, diameter of cable 3.1 mm) was introduced after wide opening of sellar floor und after intrasellar tumor removal. The parasellar and suprasellar space was scanned perpendicular to the working channel in direct contact to the sellar envelope rotating the probe around the line between nostril and center of the sella.

Results: Using colour coded flow mode it was possible to identify the intracavernous course of the ICAs in all cases and to operate safely close to the artery (no injury of the vessel). After intrasellar tumor resection parasellar tumor remnants due to infiltrative growth pattern were seen intraoperatively in 41 cases (33%, including 16 Knosp Grad IV tumors, and 2 cavernous sinus meningiomas), which was followed by further resection in 27 cases. Complete resection of tumors in this selected series was achieved in 90 cases (71%). The limitations of intraoperative US are fibrosis (scar, meningioma), air, bone, and limited space due to small resection cavities.

Conclusions: Intraoperative scanning of the parasellar and suprasellar space with ultrasound probes in direct contact to the sellar envelope enables the surgeon to quickly identify tumor remnants intraoperatively and to perform tailored resection even in infiltrative tumors.