title: Preoperative ultrasound measurements predict the feasibility of gallbladder extraction during transgastric natural orifice translumenal endoscopic surgery cholecystectomy.
abstract: BACKGROUND
  Extraction of a gallbladder through an endoscopic overtube during natural orifice translumenal endoscopic surgery (NOTES) transgastric cholecystectomy avoids potential injury to the esophagus. This study examined the rate of successful gallbladder specimen extraction through an overtube and hypothesized that preoperative ultrasound findings could predict successful specimen passage.
  
  
  METHODS
  Gallbladder specimens from patients undergoing laparoscopic cholecystectomy were measured, and an attempt was made to pull the specimens through a commercially available overtube with an inner diameter of 16.7-mm. A radiologist blinded to the outcomes reviewed the available preoperative ultrasound measurements from these patients. Ultrasound dimensions including gallbladder length, width, and depth; wall thickness; common bile duct diameter; and size of the largest gallstone (LGS) were recorded. Multiple logistic regression analysis was performed to determine whether ultrasound findings and patient characteristics (age, body mass index [BMI], and sex) could predict the ability of a specimen to pass through the overtube.
  
  
  RESULTS
  Of 57 patients, 44 (77%) who had preoperative ultrasounds available for electronic review were included in the final analysis. Gallstones were present in 35 (79%) of these 44 patients. Intraoperative gallbladder perforation occurred in 18 (41%) of the 44 patients, and 16 (36%) of the 44 gallbladders could be extracted through the overtube. Measurement of LGS was possible for 23 patients, and indeterminate gallstone size (IGS) was determined for 12 patients. The rate for passage of perforated versus intact gallbladders was similar (40% vs. 23%; p = 0.054). The LGS (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.02-1.33; p = 0.021) and IGS (OR, 22.97; 95% CI, 1.99-265.63; p = 0.025) predicted failed passage on multivariate logistic regression analysis. The passage rate was 80% for LGS smaller than 10 mm or no stones present, 18% for LGS 10 mm or larger, and 8% for IGS (p < 0.001).
  
  
  CONCLUSIONS
  A majority of cholecystectomy specimens cannot pass through an endoscopic overtube. Preoperative ultrasound findings can predict successful specimen extraction. An IGS or a gallstone 10 mm or larger should be considered a relative contraindication to transgastric NOTES cholecystectomy.
authors.affiliation: Department of Surgery, Northwestern University Feinberg School of Medicine, 676 North Saint Clair Street, Suite 650, Chicago, IL 60611, USA.
authors.forename: Byron F
authors.initials: BF
authors.lastname: Santos
authors.forename: Edward D
authors.initials: ED
authors.lastname: Auyang
authors.forename: Eric S
authors.initials: ES
authors.lastname: Hungness
authors.forename: Kush R
authors.initials: KR
authors.lastname: Desai
authors.forename: Edward S
authors.initials: ES
authors.lastname: Chan
authors.forename: Darren B
authors.initials: DB
authors.lastname: van Beek
authors.forename: Edward C
authors.initials: EC
authors.lastname: Wang
authors.forename: Nathaniel J
authors.initials: NJ
authors.lastname: Soper
mesh_terms: D000886:Anthropometry / Q000379:methods; D015992:Body Mass Index; D002763:Cholecystectomy / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D017081:Cholecystectomy, Laparoscopic; D002764:Cholecystitis / Q000000981:diagnostic imaging / Q000601:surgery; D002769:Cholelithiasis / Q000000981:diagnostic imaging* / Q000601:surgery; D003549:Cystic Duct / Q000000981:diagnostic imaging; D017558:Elective Surgical Procedures; D004867:Equipment Design; D004947:Esophagus / Q000293:injuries; D005240:Feasibility Studies; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging* / Q000293:injuries / Q000473:pathology / Q000601:surgery; D042882:Gallstones / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D066298:In Vitro Techniques; D007431:Intraoperative Complications / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D057605:Natural Orifice Endoscopic Surgery / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D009929:Organ Size; D018579:Patient Selection; D016037:Single-Blind Method; D013270:Stomach; D014463:Ultrasonography