Objective: Premature prolapse of the diaphragma sella can interfere with the access of residual
tumor in the lateral and superior gutters. Elevation of the head relative to the heart
effectively lowers intracranial pressure (ICP), with the zero ICP achieved at the
planum point at or above 30 degrees. For pituitary tumor patients with a large amount
of suprasellar extension, we utilized the reverse Trendelenburg when necessary to
elevate a prematurely descended diaphragm, which then allowed improved visualization
of the surgical gutters for complete tumor removal. Our aim is to determine whether
RT can safely be used in transnasal transsphenoidal surgery (TNTS) without negatively
affecting surgical outcomes and complications.
Methods: We performed an Institutional Review Board approved retrospective analysis of all
patients who underwent TNTS resection of a pituitary tumor from November 12, 2014
to August 16, 2019, and identified 86 patients for whom the use of RT (estimated at
30–45 degrees) during the operation was recorded by the surgeon in the operative report.
Descriptive statistics were used for data analysis.
Results: RT was used in 12 out of 86 patients. There were no major complications, including
air or pulmonary embolism, observed in any patients in this series, despite cavernous
sinus dissection and use of hemostatic foam. In the patient group where RT was not
used, there was a 36% intraoperative CSF leak rate (12 grade 1, 14 grade 2, and 1
grade 3), compared with a 25% intraoperative CSF leak rate (2 grade 1 and one grade
2) in the patient group where RT was employed (p > 0.05). Out of 74 patients without use of RT, four had a possible gross total resection
(GTR) and 56 had a GTR, compared with 6 patients with GTR out of the 12 patients with
intraoperative RT use (p = 0.05).
The average tumor size for patients who underwent RT positioning was 31.5 mm; 25%
had cavernous sinus invasion, 67% had suprasellar extension, and 50% were adherent.
The average tumor size for patients who did not undergo RT positioning were 14 mm,
respectively; 15% had cavernous sinus invasion, 23% had suprasellar extension, and
42% were adherent. Patients with suprasellar extension of the tumor (p < 0.05), larger tumor size (p < 0.001), and Knosp's grade 3 or 4 (41.6 vs. 23.0%) were more likely to undergo intraoperative
RT positioning then patients for whom RT was not used.
Conclusion: RT can be a helpful surgical positioning aid for large sellar tumors, especially
when there is suprasellar extension or cavernous sinus involvement, as it allows for
diaphragma sellae ascent, providing better visualization of remaining tumor, and decreases
venous oozing. We found no apparent major complications, including air embolism, in
our series of patients. No significant difference was found in gross total resection.
Of note, RT was most often used in larger, more invasive tumors, with an already lower
likelihood of gross total resection. Lastly, despite the later and gravitational pull
in RT increasing the likelihood of CSF leakage, we found no significant increase in
intraoperative CSF leaks in patients where RT was used.
