A Novel Method to Locate Intracranial Anatomic Landmarks of Sella Using Three-Dimensional Computed Tomography Reconstruction Images for Endoscopic Endonasal Transsphenoidal Surgery

Preoperative 3D volume reconstruction of the posterior wall of the sphenoid sinus with Horos: A free, simple and reliable tool in endoscopic endonasal trans-sphenoidal surgery

BACKGROUND

The purpose of the study was to create computer-aided design models of the sphenoid sinus with a free-source software in order to perform a preoperative planning during trans-sphenoidal endoscopic surgery (TES) and clarify the three-dimensional anatomical features of the sphenoid sinus and its surrounding structures.

METHODS

For each patient a 3D volume rendering of the sphenoid sinus was obtained from a thin slice head and maxilla-facial CT scan using a free-source DICOM viewer. The 3D models obtained preoperatively were examined preoperatively by six neurosurgeons in order to identify the boundaries of the sella.

RESULTS

For the main anatomical landmark, all of the observers were able to recognize the anatomical structure at a rate ranging from 80 to 98%, 28 to 60% and 25 to 58% for expert (n=3), inexpert (n=3) and the entire group of observers (n=6), respectively. The analysis of the data shows that both observation groups presented a lower recognition rate of the following parameters: right and left medial and lateral optocarotid recesses and tumor prominence, however, the sellar prominence, clival recess, planum sphenoidalis, right and left ICA prominence, right and left optic prominences represent the main anatomical landmarks to be recognized during TES immediately before the opening of the sellar floor.

CONCLUSIONS

The use of a preoperative 3D imaging is not in itself a novelty in the literature, however the fact that a simple tool obtained with a free-source software like Horos can represent a considerable help in surgical practice without resorting to the use of more complex software and expensive represents the real utility of this work.

Total intravenous versus inhaled anesthesia in transsphenoidal tumor surgery

PURPOSE

Visualization of the surgical field is essential for patient safety during endoscopic transsphenoidal tumor surgery. In this retrospective chart review and data analysis of patients undergoing endoscopic transsphenoidal resection of pituitary tumors under general anesthesia we sought to determine if total intravenous anesthesia with propofol and remifentanil leads to decreased bleeding, surgical duration, time to extubation and/or length of stay in the recovery room compared to inhaled anesthesia with sevoflurane or desflurane.

METHODS

After IRB approval, chart reviews of 193 American Society of Anesthesiologists class 1 to 3 patients were conducted who had undergone transsphenoidal, endonasal resections of pituitary tumors under total intravenous or inhaled anesthesia at an academic teaching hospital in the United States over a seven-year time period. One hundred four patients fulfilled the inclusion criteria and were further reviewed. Primary outcome was intraoperative blood loss; secondary outcomes were surgical duration, time to extubation and length of stay in the recovery room.

RESULTS

Gender, age, and Lund-Mackay-Scores were equally distributed between the two anesthetic groups. We found no significant effect of the anesthetic technique, age, gender, or Lund Mackay score on any of the primary or secondary outcomes. The only significant predictor for recovery room length of stay was intraoperative blood loss.

CONCLUSION

Our study shows no evidence that total intravenous anesthesia is superior to inhaled anesthesia or vice versa during endoscopic transsphenoidal sinus surgery with regard to relevant clinical outcome parameters.

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.

Intracranial Anatomic Landmarks for Endoscopic Endonasal Transcribriform Approach to Anterior Skull Base

OBJECTIVES

To help surgeons locating anatomic landmarks when performing endoscopic endonasal transcribriform approach to anterior skull base.

METHODS

High-resolution axial computed tomography (CT) images at thickness of 0.6 mm, and reconstructed 0.41-mm thick gapless sagittal and coronal CT images were taken from 123 subjects. Using mimics software, first located elementary points and line: nasal spine, midpoint of posterior hard palate and the line between them; then located measured points right/left posterior and anterior points; measured distances between measured points and from measured points to nasal spine and angles between lines connecting measured points to nasal spine and the basic line.

RESULTS

The distances from nasal spine to right/left posterior and anterior points of anterior skull base are 68.67 ± 6.04 and 61.71 ± 5.09 mm, corresponding angles are 45.89 ± 4.20° and 72.07 ± 4.06°, respectively. The width and length of defect of anterior skull base are 24.45 ± 2.62 and 31.03 ± 4.96 mm; its area ranges from 373.75 ± 94.08 to 800.91 ± 195.07 mm.

CONCLUSIONS

The study provides information about anterior skull base anatomic landmarks, which can help surgeons to locate them and avoid relative complications during endoscopic endonasal transcribriform approach to anterior skull base. The measurements can be used as surgical indicators to investigate the landmarks.