Tips and Tricks to Safely Perform an Endoscopic Endonasal Trans-Sphenoidal Pituitary Surgery: A Surgeon's Checklist

Abstract

The authors aimed to develop an extensive preoperative checklist of CT scan findings during endoscopic access to the ventral skull base and implement it in clinical practice. A comprehensive literature review was conducted to identify the radiological landmarks crucial to endoscopic skull base surgery. Four electronic databases were searched: PubMed, MEDLINE, EMBASE, and Google Scholar using search terms/keywords such as "radiological landmarks," "endoscopic skull base surgery," "CT scan," "pituitary surgery," "anatomical variations," "internal carotid," "optic nerve," "sphenoid sinus," "pneumatization," "dehiscence," and "protrusion". Inclusion criteria were limited to original articles and systematic reviews published in English, between the years 2000 and 2021, which pertained to the radiological landmarks to be identified during endoscopic skull base surgery. Full-text articles were retrieved and collated into a narrative review focused on a 12-item checklist the authors agreed upon. The mnemonic "O ROAD TO SELLA" was used to represent the checklist and include the following landmarks: Sphenoid Ostium, Sphenoid Rostrum, Onodi cells, Anatomic variations of the sphenoid sinus, Distance between the carotids, Tumor characteristics, Optic nerve dehiscence/protrusion, Septation/insertion of the sphenoid sinus, Entrance to the sellar floor, Lateral recess of the sphenoid sinus, cLinoid process pneumatization, and internal carotid Artery dehiscence/protrusion. The checklist is designed to be used by attending physicians, fellows, and residents and the authors intend to implement it into electronic medical records at the institution's medical center to monitor the outcomes of EEPS after implementation.

Keywords: Anatomical variations; Endoscopic sinus surgery; Pituitary surgery; Preoperative checklist; Radiological landmarks.

Fig. 1

CT scan showing different types of sphenoid sinus pneumatization patterns; a Conchal type; c Pre-cellar; d Sellar; e Post cellar

Fig. 2

CT scan showing pneumatization of the lateral recess of the sphenoid sinus

Fig. 3

CT scan showing anterior clinoid process pneumatization

Fig. 4

CT scan showing a free-floating optic nerve

Fig. 5

Intra-operative endoscopic demonstration of a free-floating optic nerve

Fig. 6

CT scan showing the natural sphenoid ostium and sphenoethmoid recess

Fig. 7

CT scan showing vital structures surrounding the sphenoid ostium such as the optic nerve, internal carotid artery, and the cavernous sinus

Fig. 8

Intra-operative endoscopic view of the sphenoid sinus with an adjacent Onodi cell

Fig. 9

CT scan showing the insertion of the inter-sphenoid sinus septum on the internal carotid artery

Fig. 10

Intra-operative endoscopic image of a free-floating optic nerve

Fig. 11

Intra-operative endoscopic image of a transected optic nerve

Fig. 12

MRI image showing kissing internal carotid artery

Fig. 13

Intra-operative endoscopic view of kissing internal carotid artery

Fig. 14

Intra-operative endoscopic view of an internal carotid artery dehiscence