Introduction

Seatbelt safety

Fatal injuries to drivers and front seat occupants can be reduced by 40– 50% and to rear seat occupants by 25–75% when seat belts are worn by passengers in motor vehicle collisions [1]. Nevertheless, seat belts have also long been associated with certain injuries. The first injury was described in 1948 by Chance et al. This lumbar fracture dislocation of the lumbar spine occurs when the lap belt acts as fulcrum and the occupant’s spine is subjected to a combination of hyperflexion and axial tension [2].

TAWH

Traumatic abdominal wall hernias (TAWH), including lumbar hernias, may occur within the superior or inferior lumbar triangle. Both triangles represent areas of relative weakness in the posterolateral abdominal wall. The superior lumbar triangle (Grynfelt-Lesshaft triangle) is an inverted triangle bordered superiorly by the 12th rib, anteriorly by the internal oblique muscle, and posteriorly by the erector spinae muscle. The latissimus dorsi muscle forms the roof of the triangle, and the aponeurosis of the transversalis muscle forms the floor. The inferior lumbar (Petit’s) triangle is an upright triangle bordered inferiorly by the iliac crest, anteriorly by the external oblique muscle, and posteriorly by the latissimus dorsi muscle. Superficial fascia and skin constitute the roof of the triangle, and the lumbar fascia, internal oblique muscle, and aponeurosis of the transversalis muscle form the floor [3]. See Fig. 1.

Fig. 1: Drawing of the anatomy of the dorsal muscular wall with the inferior (A) und superior lumbar triangle

TAWH was first described by Doersch and Dozier in 1968 [4] and is usually visualized by CT scans [3]. In a recent metaanalysis CT scans could establish the diagnosis in all but one case (97.7%) [5]. TAWH is a rare injury in emergency rooms, especially in high-velocity road traffic accidents [6]. It is often associated with other injuries, particularly intra-abdominal injuries [7].

The TAWH is often overlooked clinically, together with other abdominal wall injuries such as rectus sheath haematomas and Morel-Lavallée lesions [8]. They are uncommon in a clinical setting, accounting for only 0.17–1.5% of all blunt trauma admissions [9–11]. The most frequent mechanism of injury is a motor vehicle collision [10, 12] and was associated with a deceleration injury from a seat belt [10]. The most common localization is the inferior lumbar triangle (81%) [10] but a TAWH can occur in other locations of the abdominal wall as well [13].

A recent systematic review suggests that early recognition is key in the clinical diagnosis of TAWH, even when it is not the primary life-threatening injury [14].

Aim of the study

To determine the overall incidence of TAWH in a large postmortem collective of trauma cases.To evaluate the specificity of motor vehicle occupant TAWH in accidents by comparing its occurrence across different accident mechanisms.To identify and quantify correlations between the presence of TAWH and other characteristic injury patterns found in motor vehicle occupants.To investigate the specific association between TAWH and seatbelt use to assess its potential as a seatbelt-related injury.