This study innovatively explored simple indexes of abdominal shape such as PAAD, LSA and other parameters on short-term surgical outcomes in patients undergoing LADG. We found that abdominal shape can influence the operation time, estimated blood loss, postoperative hospital stay, the number of retrieved lymph nodes and the complications. Furthermore, abdominal body shape differed between sexes, and males had larger APDs and smaller SFTs than females. Therefore, we analyzed males and females separately and found that few abdominal shape parameters had an impact on short-term surgical outcomes in females. However, in males, we found that some abdominal shape parameters were crucial. This result was consistent with the previously published literature.10–11, 15
Obesity has always been considered an independent factor in patients with gastric cancer. BMI can be a parameter to represent obesity. Some studies believe that BMI has an impact on postoperative complications and survival.16–17 In this study, males with a lower BMI had a shorter operation time and a smaller estimated blood loss. Obesity has an impact on the difficulty of performing LADG in male patients.
The operation time and estimated blood loss can reflect the difficulty of the operation. Previous studies have found that a large APD can increase the operation time and that a large LRD can increase the amount of surgical bleeding.10–11 In this study, a larger PAAD, LSA, SFT, APD and LRD contributed to an increase in the operation time in males. For estimated blood loss, male patients with larger LSA, PAAD, APD, SFT and LRD could experience larger amounts of estimated blood loss, but all parameters had a negative relationship in females. Different distensibilities of the abdominal wall in males and females due to the accumulation of muscle and lipids may explain why the abdominal shape was more strongly associated with male patients than female patients.18 The extra operation time and blood loss may be due to the large size of the abdominal shape and excess fat tissues accumulating around vessels.11 However, a larger LSA resulted in a larger amount of estimated blood loss in males, and the cause remained unclear because the LSA is made up of the xiphoid and the rib arch, and it is relatively fixed. A previous study reported that the LSA could be a simple predictive index for a larger estimated blood loss during laparoscopy-assisted total gastrectomy. The possible reason for this is that a larger LSA could cause the five trocar sites to be closer, and the instruments might then interfere with each other, which increases the difficulty of the operation and might cause more blood loss.14 We considered that the LSA may increase the space in the abdominal cavity, leading to difficulty and extra blood loss.
Previous studies reported that postoperative complications ranged from 6.1–30%.5,11,19−20 These studies focused on the associations of BMI and visceral fat with postoperative complications.21–22 In this study, the rate of postoperative complications was 24.7%, and a higher PAAD was an independent factor for predicting postoperative complications in males. This might be because of the large size of the abdomen that affects the safety of LADG, so surgeons should be cautious about operating on patients with a higher PAAD.
The number of retrieved lymph nodes is related to the effectiveness of the operation. An insufficient number of retrieved lymph nodes may lead to a poor prognosis.23–24 In this study, males with a lower APD had more retrieved lymph nodes, and it seems that smaller parameters of the abdominal shape can make LADG surgery more effective. Therefore, much attention should be given to patients with larger parameters of the abdominal shape.
This study has some limitations as well. First, this is a retrospective study in a single center. Second, this study only included patients undergoing LADG, and there may be some patients who underwent open gastrostomy because of obesity or were converted to open gastrostomy due to the large amount of bleeding or the difficulty of LADG. Third, this study used CT to estimate the LSA. Ideally, we think of the rib arch as a straight line, but actually, the rib arch is a curve, and some patients have asymmetrical bilateral costal arches. The calculation of the angle in this study may have some deviations.
In conclusion, various abdominal shapes can influence the difficulty of LADG. A larger PAAD is an independent factor for predicting postoperative complications in males.