The clinical significance of the corona mortis within a South African sample

Abstract

The Modified Stoppa approach to the pelvis offers extensive exposure to the anterior column of the pelvic bone which is especially vital during the repair of pelvic ring and acetabular fractures. Definitive pitfalls of this procedure are the adverse effects resulting from the inadvertent severing of the Corona Mortis (CM) vessels, a clinical term referring to the anastomosis between the obturator vessels and the external iliac vessels typically via an accessory obturator vessel. This study investigated the incidence and variations of the CM in a South African sample using 63 adult cadavers from the Department of Anatomy, University of Pretoria and 73 patient computed tomography (CT) angiograms from the Department of Diagnostic Radiology, Universitas Hospital. The cadaver study involved careful dissection of the pelvic blood supply, thereafter, incidence and distances of the CM in relation to bony landmarks encountered during anterior approaches to the pelvis were documented. These landmarks included the pubic tubercle, pubic symphysis and the anterior inferior iliac spine. The angiogram study consisted of precise observation of pelvic CT scans at the superior pubic ramus in order to record the incidence and distances of the CM to the above-mentioned bony landmarks. These distances were evaluated to create ‘safe zones’ for pelvic exposure during orthopaedic procedures. The accuracy of the safe zones were then validated via a cadaver simulation of the Modified Stoppa approach on two adult cadavers from the Department of Anatomy, University of Pretoria to prove the CM lies outside of the safe zone. The incidence of the CM was observed as 67.5% of the cadaver study sample and 33.1% of the angiogram sample. The CM safe zones related to the pubic tubercle resulted in 60.3 mm for the cadaver study and 49.1 mm for the angiogram study. Discrepancies between the anatomical and clinical study were evident as a significant difference between the results of the cadaver and angiogram studies was calculated. Therefore, it is recommended that angiographic study of the CM should be limited to diagnostic purposes when confirming the presence of the CM. The high incidence and compromising location of the anastomosis proves it is clinically significant.