Skull base ligamentous mineralisation: evaluation using computed tomography and a review of the clinical relevance

Abstract

Objectives To determine the frequency, morphologic and demographic characteristics, and clinical relevance of the mineralisation of six skull base ligaments (interclinoid, caroticoclinoid, petrosphenoid, posterior petroclinoid, pterygospinous, and pterygoalar). Methods This is a retrospective review of 240 CT scans of the paranasal sinuses (ages 6–80 years). A limited systematic review was performed primarily using Embase and Medline databases. Results Ligamentous mineralisation was well delineated on CT and occurred at ≥ 1 location in 58.3% of patients. There was a nonsignificant trend towards a greater incidence with advancing age. The interclinoid and posterior petroclinoid ligaments were most commonly mineralised (22.1% and 18.3%, respectively); the petrosphenoid and pterygoalar ligaments were least frequently mineralised (10.8% and 6.3%, respectively). The mean age of patients with posterior petroclinoid mineralisation was significantly greater than those with interclinoid and petrosphenoid mineralisation and was not seen in patients aged 6–20 years. The literature review highlighted the clinically relevant potential for mineralised ligaments to cause barriers to surgical access (e.g. to the foramen ovale), increase the risk of neurovascular injury during surgery at the skull base (e.g. during anterior clinoidectomy), and predispose to neural impingement. Conclusions Skull base ligamentous mineralisation is commonly encountered on CT imaging. Given the potentially significant clinical implications, an understanding of the morphological appearances is of importance to those planning interventions at the skull base. To the authors’ knowledge, this study is the first to comprehensively evaluate such a wide range of skull base ligaments using CT. For some ligaments, the incidence on CT has not been previously described.

Microsurgical Anatomy of the Inferomedial Paraclival Triangle: Contents, Topographical Relationships and Anatomical Variations

“…Such variation was observed in our material in two cases in which the presence of ossification within the dura covering inferomedial triangle was confirmed histologically. Similar findings have also been described in anatomical and radiographic reports [ 14 , 15 , 16 , 17 , 18 , 19 ]. Touska et al [ 18 ] concluded that ligamentous skull base mineralizations are relatively common findings on CT scans.…”

“…Similar findings have also been described in anatomical and radiographic reports [ 14 , 15 , 16 , 17 , 18 , 19 ]. Touska et al [ 18 ] concluded that ligamentous skull base mineralizations are relatively common findings on CT scans. In the majority of cases, intracranial calcifications or ossifications are not accompanied by any detectable pathology [ 14 , 19 ].…”

Physiological Intracranial Calcifications - A Study in Coastal Karnataka

“…A detailed study of skull base ligamentous mineralization by Touska P et al showed similar evidence of mineralization in 58.3% of patients. 6 Amongst all intracranial calcifications, pineal calcifications have been studied in detail. Zimmerman et al in 1982 stated that pineal calcifications in patients less than 6 years should be viewed with suspicion 7 .…”

The Pterygospinous Foramen (Civinini) and the Pterygoalar (Crotaphitico-Buccinatorius). Laboratory Findings

“…The ossification of fibrous tissues and/or ligaments associated with sphenoid bone are common and occur in up to 58.3 %, according to a large study conducted by Touska et al (2019), and among these occurrences, and with neurological and surgical relevance, we note the pterygospinous and pterygoalar foramen (crotaphitico-buccinatorius) (Goyal & Jain, 2016). These foramen are atypical formations of the homonymous ligaments present in the sphenoid bone and, due to their positions, of paramount importance because they make extracranial access procedures more difficult, mainly aiming at the oval foramen and its surroundings (Isolan & Al-Mefty, 2008;Erdogmus et al, 2009;Suazo et al, 2010;B & K, 2014;Singh & Niranjan, 2019;Somayaji et al, 2019;Henry et al, 2020).…”