Application of the Three Points and Three Lines Method to Accurately Open the Sellar Floor in Microscopic Transsphenoidal Surgery of Pituitary Adenomas

OBJECTIVE

In this study, the sellar floor morphology of patients with pituitary adenoma is analyzed and a simple yet reliable method is identified to determine the location of bone window opening.

METHODS

Clinical information of 144 consecutively admitted patients was retrospectively analyzed. Enhanced magnetic resonance imaging of the midsagittal plane was selected as the reference for classifying the sellar floor. Intraoperative tumor location, extent of tumor resection, and follow-up results were analyzed for different types of sellar floor. The tuberculum sellae, lowest point of the sphenoid sinus, and the lowest point of the sellar floor and 3 lines related to them were used to classify the sellar floor. This is referred to as the "three points and three lines" method.

RESULTS

Based on its location in the sphenoid sinus, the sellar floor can be classified into 4 types: 12 patients (8.3%) with high sellar, 70 (48.6%) with medium sellar, 30 (20.8%) with low sellar, and 32 (22.8%) with steep sellar. The maximum tumor diameter, maximum sellar floor diameter, and the intercarotid distance were all significantly different among patients with different types of sellar floor (P < 0.001). For all patients, quick intraoperative location of the sellar floor opening was achieved. A total of 104 patients (72.2%) had total tumor resection, 28 (19.40%) had subtotal tumor resection, and 4 (2.8%) had partial tumor resection. Twenty patients (13.9%) experienced cerebrospinal fluid leak, and there was no significant difference in cerebrospinal fluid leak rate among groups.

CONCLUSIONS

Presurgical classification and location of the sellar floor are critical for understanding and assessing the transsphenoidal approach. Different types of sellar floor appeared in the surgery with different morphologic features. The three points and three lines method helps the surgeon to predetermine the location of the sellar floor opening and to shorten surgical time.

Imaging Evaluation of the Location and Fenestration of Sellar Floor During Endonasal Transsphenoidal Surgery in Patients with Pituitary Adenomas

OBJECTIVE

To evaluate clinical value of three-dimensional (3D) computed tomography (CT) reconstruction of the sphenoid sinus separation in localizing sellar floor during endonasal transsphenoidal surgery and determine size and location of sellar floor fenestration.

METHODS

There were 51 patients eligible for study inclusion. Preoperative CT scan of the paranasal sinus and CT scan and magnetic resonance imaging of the pituitary gland were obtained. Sphenoid sinus separation was reconstructed using Mimics 15.0 software, and quantity, shape, and orientation were observed and compared with intraoperative data to guide the localization of sellar floor. Anatomic variation of the sphenoid sinus and adjacent structures, tumor and sella turcica morphology, minimal distance between the cavernous segment of the internal carotid artery bilaterally, and shortest distance from the midline were measured.

RESULTS

Based on the shape of the sphenoid sinus separation, sellar floor was accurately localized in all cases. Intraoperative sphenoid sinus separation was consistent with preoperative three-dimensional CT reconstruction images. The sellar floor was extremely small in 2 patients, and insufficient fenestration of sellar floor negatively affected tumor resection. Preoperative three-dimensional CT reconstruction is helpful for accurate and rapid localization of sellar floor.

CONCLUSIONS

Anatomic variation of sphenoid sinus and adjacent structures, characteristics of tumor and sella, minimum distance between bilateral cavernous segment of the internal carotid artery, and shortest distance from midline are helpful for establishment of individualized sellar floor fenestration.