Abdominal Wall Thickness at Palmer's Point and Distance to Adjacent Structures across the Body Mass Index Spectrum

Abstract

Studies delineating left upper quadrant (LUQ) anatomy across a range of body mass indices are lacking. We aimed primarily to compare, between nonobese and obese women, abdominal wall thickness and the distance from the LUQ to key structures. In addition, we aimed to characterize LUQ anatomy in underweight women. A retrospective cohort study. A tertiary academic medical institution. Sixty women (30 nonobese, 30 obese) aged 18 years and older who underwent abdominal imaging from October 1, 2018, to December 31, 2018. Computed tomography imaging of the chest, abdomen, and pelvis. Abdominal wall thickness at the LUQ was significantly greater in obese (4.3 ± 1.7 cm) than nonobese patients (2.4 ± 1.7 cm) (p <.001), as were distances to all key structures (aorta, vena cava, spleen, stomach, pancreas, liver, left kidney, and pelvis) (p ≤.02). On average, all structures, with the exception of stomach and liver, were >10 cm (the length of a typical insufflation needle) away from the LUQ insertion point in obese women. In underweight women, the aorta, spleen, stomach, pancreas, and liver were all within 10 cm of the LUQ insertion point. Within the obese and nonobese group, abdominal wall thickness at the LUQ was significantly greater than at the umbilicus (p <.001). Body mass index was more strongly correlated with abdominal wall thickness at the LUQ (r=0.84; p <.001) than at the umbilicus (r=0.69; p <.001) (p=.007 for comparison). This study highlights special anatomic considerations for LUQ access in obese and underweight patients. In obese women, abdominal wall thickness may be greater at this site than at the umbilicus and the liver and stomach remain within reach of an insufflation needle. The increased working distance from the LUQ to the pelvis in obese patients may necessitate specialized instruments if this site is used during surgery. In underweight women, the aorta, in addition to many other structures, is within reach of commonly used entry devices.