Anatomical Variation of Abdominal Wall Musculature: An Objective Assessment Using Cross-Sectional Imaging.

Purpose: To determine normal anatomical variation of abdominal wall musculature. Methods: A retrospective analysis of CT scans was performed on adults (>18 years) with normal abdominal wall muscles. Two radiologists analysed the images independently. Distances from three fixed points in the midline were measured. The fixed points were; P1, mid-way between xiphoid and umbilicus, P2, at the umbilicus, and P3, mid-way between umbilicus and pubic symphysis. From these three fixed points the following measurements were recorded; midline to lateral innermost border of the abdominal wall musculature, midline to lateral edge of rectus abdominis muscle, and midline to medial edges of all three lateral abdominal wall muscles. To obtain aponeurotic width, rectus abdominis width was subtracted from the distance to medial edge of lateral abdominal wall muscle. Results: Fifty normal CT scan were evaluated from between March 2023 to August 2023. Mean width of external oblique aponeurosis at P1 was 16.2 mm (IQR 9.2 mm to 20.7 mm), at P2 was 23.5 mm (IQR 14 mm to 33 mm), and at P3 no external oblique muscle was visible. Mean width of the internal oblique aponeurosis at P1 was 32.1 mm (IQR 17.5 mm to 45 mm), at P2 was 10.13 (IQR 1 mm to 17.5 mm), and at P3 was 9.2 mm (IQR 3.0 mm to 13.7 mm). Mean width of the transversus abdominis aponeurosis at P1 was -25.1 mm (IQR 37.8 mm to -15.0 mm), at P2 was 29.4 mm (IQR 20 mm to 39.8 mm), and at P3 was 20.3 mm (IQR 12 mm to 29 mm). Conclusion: In this study we describe normal anatomical variation of the abdominal wall muscles. Assessing this variability on the pre-operative CT scans of ventral hernia patients allows for detailed operative planning and decision making.

A Ventral Hernia Management Pathway; A "Getting It Right First Time" approach to Complex Abdominal Wall Reconstruction.

INTRODUCTION: Abdominal wall reconstruction (AWR) is an emerging specialty, involving complex multi-stage operations in patients with high medical and surgical risk. At our hospital, we have developed a growing interest in AWR, with a commitment to improving outcomes through a regular complex hernia MDT. An MDT approach to these patients is increasingly recognized as the path forward in management to optimize patients and improve outcomes. METHODS: We conducted a literature review and combined this with our experiential knowledge of managing these cases to create a pathway for the management of our abdominal wall patients. This was done under the auspices of GIRFT (Getting It Right First Time) as a quality improvement project at our hospital. RESULTS: We describe, in detail, our current AWR pathway, including the checklists and information documents we use with a stepwise evidence and experience-based approach to identifying the multiple factors associated with good outcomes. We explore the current literature and discuss our best practice pathway. CONCLUSION: In this emerging specialty, there is limited guidance on the management of these patients. Our pathway, the "Complex Hernia Bundle," currently provides guidance for our abdominal wall team and may well be one that could be adopted/adapted by other centers where challenging hernia cases are undertaken.