Computed tomography pattern of anatomical variants among patients undergoing transnasal transsphenoidal endoscopic surgery for pituitary macroadenoma at Muhimbili Orthopedic Institute

Abstract

Background Transnasal Transsphenoidal Endoscopic Surgery has become the most common choice to treat skull base lesions including pituitary macroadenoma. Its suitability depends on anatomical variants such as sinonasal variants, the extent of sphenoid sinus pneumatization and bone coverage of cavernous portion of ICA. CT scans have proven to be vital and sufficient in imaging of the paranasal sinuses since it provides excellent contrast as well as sinonasal anatomic details. Hence it is important to careful evaluate these variants preoperatively by CT scan for lesser intra and postoperative complications. Objective The study was conducted in particular to assess anatomic variants among adult patients with pituitary macroadenoma planned for TTES at MOI from October 2020 to April 2021. Methodology This was a hospital based descriptive prospective cross-sectional study of all adult patients who were diagnosed with pituitary macroadenoma by both CT and MRI. It was done at MOI in the Neurosurgical and Radiology Departments using a structured questionnaire/checklist data collection tool. Information included socio-demographics and CT Head findings of sinonasal variants, sphenoid sinus pneumatization types and bony coverage of cavernous portion of ICA in relation to TTES. CT scan imaging was done using Siemens CT Somatom Definition 128slices, manufactured by Siemens in Germany. Data analysis was done using SPSS version 23 and summarized using tables and figures. The observed differences were considered significant at p value < 0.05. Results A total of 103 patients diagnosed with pituitary macroadenoma by CT/MRI were enrolled, males were 46 (44.66%) and females were 57 (55.34%). Age ranged between 18-95 years with mean age of 48.11 years. Among the sinonasal variants studied, majority of the patients had deviated intersphenoid septum (ISS) accounting for 60 patients (58.25%) and the least was xi Onodi cells observed among 4 patients (3.88%). The commonest type of sphenoid sinus pneumatization was sellar observed among 92 patients (90.3%). Bilateral partial bony coverage of cavernous ICA was observed among 22 patients (21.4%). Conclusion CT scan plays an important role in the assessment of anatomic variants in the nasal cavity and the SS as far as TTES is concerned so as to make preoperative imaging evaluation not only crucial for diagnosis but also valuable for surgical mapping to ensure safe access and improved surgical outcomes. Therefore, the role of both the radiologists and neurosurgeons is to carefully evaluate them for a desirable outcome. Recommendation CT scan is mandatory and a necessary tool for evaluation of anatomical variants prior to undergoing TTES. Hence it is a role of every radiologist to report these variants in all patients with pituitary macroadenoma