Safety Precautions for the Corona Mortis using Minimally Invasive Ilioinguinal Approach in Treatment of Anterior Pelvic Ring Fracture

OBJECTIVE: To explore the safety of the corona mortis of the minimally invasive plate insertion in treatment of the anterior pelvic ring fracture by studying the relationship between the vessel and the position of plate. METHOD: The corona mortis was dissected out of eight adult cadavers and were simulated for the insertion of the anterior ring minimally invasive plate, and the presence of the anastomotic branch (the corona mortis) in the suprapubic branch area was observed. After the Corona mortis stripped off, the data was measured, such as the length, vessel diameter, distance from the pubic tubercle, and the maximum vertical distance between the corona mortis and the pubis. The measured data and the previous literatures were analyzed to study the morphology of the corona mortis and the position relation between the corona mortis and the placement of subperiosteal tunnel through the minimally invasive ilioinguinal approach. RESULTS: Out of the 16 unilateral pelvises, the corona mortis were observed on 12 unilateral pelvises with an incidence rate of 75%. Amongst them, there were seven cases of vein anastomosis (incidence of 43.75%), three cases of arterial anastomosis (incidence of 18.75%), and two cases of both arterial anastomosis and vein anastomosis (incidence of 12.5%). The corona mortis length ranged between 24.5 and 37.5 mm (average of 30.7 ± 3.6 mm); the diameter ranged between 1.6 and 3.5 mm (average of 2.5 ± 0.5 mm) and the distance between the vessels and the pubic tubercle was between 53.9 and 65.2 mm (average of 59.0 ± 3.6 mm). Above the pubis, the corona mortis originated from the iliac or the inferior epigastric vessel. It crossed the pubic branch to the dorsal side of the pubis and proceeded downward to anastomize with the obturator vessels near the obturator. Toothless tweezers were used to peel and lift up the corona mortis from the pubic bone. The maximum vertical distance between the corona mortis and the pubis ranged between 8.8 and 18.3 mm (average of 12.6 ± 3.0 mm). CONCLUSION: The corona mortis have a high rate of incidence, with a large number of differences in the type and shape of blood vessels among patients. Following peeling, the movement between the corona mortis and pubic bone is limited. Nevertheless, the plate and bone exfoliator still passed safely. Therefore, when surgeons use the minimally invasive ilioinguinal approach to establish channels, the process of subperiosteal stripping must be performed to avoid any accidental injury.