title: Development of a feasible transrectal natural orifice transluminal endoscopic surgery (NOTES®) approach in a cadaveric appendectomy model: anterior is better.
abstract: BACKGROUND
  The transrectal natural orifice transluminal endoscopic surgery (NOTES) approach is a potentially promising alternative to transgastric or transvaginal approaches for intraperitoneal procedures. However, whether the optimal transrectal approach for intraperitoneal surgery is anterior or posterior remains unknown. To evaluate this, a prospective comparison of anterior and posterior transrectal NOTES approaches in a cadaveric appendectomy model was performed.
  
  
  METHODS
  Operations were performed on human cadavers using a transanal endoscopic microsurgery (TEM) scope to assist with access and closure. Posterior access was achieved by tunneling cephalad through the retrorectal space into the peritoneal cavity. Anterior transrectal access was established through the rectal wall just above the peritoneal reflection. A dual-channel flexible endoscope was used to perform appendectomies. Rectotomies were closed using sutures or staples. Operative time, degree of laparoscopic assistance, complications, and leak-testing results were recorded.
  
  
  RESULTS
  This study investigated 10 cadavers with access and closure attempted using both anterior (n = 10) and posterior (n = 5) approaches, whereas appendectomies were performed using either an anterior (n = 8) or a posterior (n = 2) approach. The anterior approach required less time than the posterior approach for peritoneal access (4 ± 1 vs. 61 ± 14 min; p < 0.001), specimen extraction (2 ± 1 vs. 5 ± 1 min; p < 0.01), and the total operation (99 ± 35 vs. 176 ± 26 min; p = 0.02). A "pure" NOTES dissection was possible with the anterior approach using rigid transanal instruments for assistance. Dissection time, closure time, and the incidence of complications were similar between the two approaches. Leak testing of closures showed significant variability for all closure types.
  
  
  CONCLUSIONS
  Transrectal NOTES appendectomy is feasible in a cadaveric model using an anterior transrectal approach. This approach is technically easier, results in shorter operative times, and allows for a "pure" NOTES dissection compared with a posterior transrectal approach. Leak pressure testing of NOTES closures is unreliable in the cadaveric model.
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: Eric S
authors.initials: ES
authors.lastname: Hungness
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Boller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001062:Appendectomy / Q000009:adverse effects / Q000379:methods*; D002102:Cadaver; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057605:Natural Orifice Endoscopic Surgery / Q000009:adverse effects / Q000379:methods*; D011351:Proctoscopy / Q000009:adverse effects / Q000379:methods*; D011446:Prospective Studies; D013529:Surgical Wound Dehiscence / Q000209:etiology; D058106:Wound Closure Techniques