Abstract
Introduction Preoperative high-resolution computed tomography (HRCT) is essential in patients
undergoing transsphenoidal surgery to identify potential high-risk anatomic variations.
There is no consensus in the literature, as to which grading system to use to describe
these variants, leading to inconsistent terminology between studies. In addition,
substantial variability exists in the reported incidence of anatomic variants. In
this study, we performed an institutional imaging analysis and literature review with
the objective of consolidating and clearly defining these sphenoid sinus anatomical
variations. In addition, we highlighted their surgical implications and propose a
checklist for a systematic assessment of the sphenoid sinus on preoperative CT.
Methods Review of the literature and retrospective analysis assessing several imaging parameters
in 81 patients who underwent preoperative HRCT imaging for endoscopic transsphenoidal
tumor resection from January 2008 through July 2015 at Rush University Medical Center.
Results The most common sphenoid pneumatization patterns were sellar (45%) and postsellar
(49%) types. Anterior clinoid process (ACP) pneumatization was seen in 17% of patients
with high concordance of ipsilateral optic nerve (ON) protrusion. ON protrusion and
dehiscence was present in 17 and 6% of patients, respectively. Internal carotid artery
(ICA) protrusion and dehiscence was present in 30 and 5% of patients, respectively.
Dehiscence rates from local bone invasion overlying the ICA and ON occurred in 17
and 4% of cases, respectively.
Conclusions Our study highlights and reviews the key variants that have potential to impact surgical
complications and outcomes in a heterogeneous patient population. The proposed preoperative
CT checklist for patients, undergoing transsphenoidal surgery, consistently identifies
these higher risk anatomical variants.
Keywords
radiology - transsphenoidal surgery - sphenoid sinus - anatomic variation - computed
tomography - preoperative Imaging
