Preoperative liver shrinking diet for bariatric surgery may impact wound healing: a randomized controlled trial

In bariatric surgery, preoperative very low-calorie diets (VLCD) may better meet the technical demands of surgery by shrinking the liver. However, diets may affect tissue healing and influence bowel anastomosis in an as-yet-undefined manner.

This randomized controlled trial aimed to examine the effect on collagen deposition in wounds in patients on a 4-week VLCD before laparoscopic gastric bypass.

University hospital.

The trial was undertaken in patients undergoing laparoscopic Roux-en-Y gastric bypass, with a control group (n = 10) on normal diet and an intervention group (n = 10) on VLCD (800 kcal) for 4 weeks. The primary outcome measured was expression of collagen I and III in skin wounds, with biopsies taken before and after the diet and 7 days postoperatively as a surrogate of anastomotic healing. Secondary outcome measures included liver volume and fibrosis score, body composition, operating time, blood loss, hospital stay, and complications.

Patients in both groups were similar in age, sex, body mass index (53.4 versus 52.8 kg/m²), co-morbidities, liver volume, and body composition. Expression of mature collagen type I was significantly decreased in diet patients compared with controls after 4 weeks of diet and 7 days after surgery. This was significant decrease in liver volume (23% versus 2%, P = .03) but no difference in operating times (129 versus 139 min, P = .16), blood loss, length of stay, or incidence of complications.

Preoperative diets shrink liver volume and decrease expression of mature collagen in wounds after surgery. Whether the latter has a detrimental effect on clinical outcomes requires further evaluation.