Defining the Clival Recess Surgical Corridor and Classification System for Sellar/Suprasellar Pathology

Objective: Endoscopic endonasal approach (EEA) for pituitary tumors has been well established. Sellar and suprasellar cysts and tumors that are within the pars intermedius, bordered anteriorly by normal pituitary gland/stalk and/or ectatic cavernous carotid artery are challenging and high risk when approached via the commonly utilized anterior trans-sellar approach. This approach portends itself to a higher risk of pituitary gland/stalk injury and subtotal tumor resection in patients with the aforementioned anatomic variants. Herein, we describe the clival recess corridor approach to these lesions. This corridor is infrequently considered in the approaches to the sella, and is a “silent” point of access lesions in this region endoscopically. While other skull base teams may have utilized this approach to some degree, it has not yet been described in the literature.

Methods: We define the clival recess surgical corridor with skull base craniometric measurements. We utilize a case example of a 61-year-old male with acromegaly and aberrant anatomy to illustrate the approach. The standard anterior trans-sellar approach was not feasible due to a small intracarotid working distance. The left cavernous carotid artery was ectatic and medialized to midline encasing the anterior pituitary gland which was anteriorly displaced secondary to the pituitary adenoma ([Fig. 1]). We reviewed 10 consecutive sellar and suprasellar masses. We defined the sagittal slice used for measurement on computed tomography angiography (CTA) as the slice in which the midline structure crista galli of the ethmoid was most prominent. We coined new terms including dorsum sella plumb line (a straight line drawn from apex of the dorsum sella through the clivus), the operative corridor (angle made from the inferior genu of the sella to the dorsum sella plumb line), and the surgical corridor (angle made from the inferior genu of the sella to the anterior most aspect of the clivus).

Results: A clival recess surgical corridor to the sella was taken. The cavernous carotid arteries and anterior pituitary gland were preserved. Here, we define the entry of the clival recess corridor: the inferior genu of the sella meets the clivus. A gross total resection was obtained without vascular, neurological, or endocrine deficits ([Fig. 2]). We found the average anatomical corridor was 54.01 degrees, the average operative corridor was 32.76 degrees, and the average length of the sellar floor to be 11.36 mm. Additionally, we created a grading scale for aeration of the clivus important for surgical planning. We classified clival aeration as Type I (100–75% aeration) ([Fig. 3]), Type II (75–50% aeration), Type III (50–25% aeration), and Type IV (25–0% aeration) ([Fig. 4]). This classification system determines the extent of drilling of the clivus required to optimize the clival recess corridor approach.

Conclusion: The endoscopic endonasal clival recess surgical corridor is effective for accessing pituitary tumors and cyst within the sella, alone, as well as those extending suprasellar. The clival recess corridor approach can be considered when a standard anterior sellar approach is high risk for vascular or endocrinological injury.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Publication History

Article published online:
15 February 2022