Preoperative transabdominal ultrasonography (US) prior to laparoscopic Roux-en-Y gastric bypass (LRYGBP) and laparoscopic sleeve gastrectomy (LSG) in the first 100 operations. Was it beneficial and reliable during the learning curve?

BACKGROUND: Preoperative ultrasonography (US) prior to laparoscopic Roux-en-Y gastric bypass (LRYGBP) aimed to find possible gallstones. The aim of this study was to evaluate the reliability of the US in evaluating the size and consistency of the left lobe of the liver.
METHODS: One hundred LRYGBP and LSG were performed in our new bariatric surgery unit by two surgeons. All patients underwent preoperative US to evaluate the size and consistency of the left lobe of the liver. A consultant radiologist reviewed the US findings, which were then compared to the intraoperative findings.
RESULTS: The mean preoperative body mass index was 49. All patients had co-morbidities. The intraoperative evaluation showed an enlarged left lobe of the liver in 23 patients, whereas the US found enlargement only in eight patients, but revealed eight false positives. In the intraoperative evaluation, fatty liver was observed in five patients, only four of whom were shown in the US, but US revealed 77 false positives. In evaluating the size of the left lobe, US had 35% sensitivity, 90% specificity, 65% false negative rate (FNR) and 10% false positive rate (FPR). In evaluating the consistency, US had 80% sensitivity, 18% specificity, 20% FNR and 82% FPR.
CONCLUSION: Preoperative US is unreliable in evaluating the size and consistency of the left lobe of the liver prior to LRYGBP and LSG and has limited prognostic value for surgical complications and complexity of surgery.