title: 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?
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland. nabil.jaser@hus.fi
authors.forename: Nabil
authors.initials: N
authors.lastname: Jaser
authors.forename: Harri
authors.initials: H
authors.lastname: Mustonen
authors.forename: Jaakko
authors.initials: J
authors.lastname: Pietilä
authors.forename: Anne
authors.initials: A
authors.lastname: Juuti
authors.forename: Marja
authors.initials: M
authors.lastname: Leivonen
mesh_terms: D015897:Comorbidity; D005260:Female; D042882:Gallstones / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005743:Gastrectomy / Q000379:methods*; D015390:Gastric Bypass / Q000379:methods*; D006801:Humans; D010535:Laparoscopy / Q000379:methods; D059032:Learning Curve; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000601:surgery; D011300:Preoperative Care; D015203:Reproducibility of Results; D016896:Treatment Outcome; D014463:Ultrasonography