title: Comparative Performance in Single-Port Versus Multiport Minimally Invasive Surgery, and Small Versus Large Operative Working Spaces: A Preclinical Randomized Crossover Trial.
abstract: BACKGROUND
  Surgical approaches such as transanal endoscopic microsurgery, which utilize small operative working spaces, and are necessarily single-port, are particularly demanding with standard instruments and have not been widely adopted. The aim of this study was to compare simultaneously surgical performance in single-port versus multiport approaches, and small versus large working spaces.
  
  
  METHODS
  Ten novice, 4 intermediate, and 1 expert surgeons were recruited from a university hospital. A preclinical randomized crossover study design was implemented, comparing performance under the following conditions: (1) multiport approach and large working space, (2) multiport approach and intermediate working space, (3) single-port approach and large working space, (4) single-port approach and intermediate working space, and (5) single-port approach and small working space. In each case, participants performed a peg transfer and pattern cutting tasks, and each task repetition was scored.
  
  
  RESULTS
  Intermediate and expert surgeons performed significantly better than novices in all conditions (P < .05). Performance in single-port surgery was significantly worse than multiport surgery (P < .01). In multiport surgery, there was a nonsignificant trend toward worsened performance in the intermediate versus large working space. In single-port surgery, there was a converse trend; performances in the intermediate and small working spaces were significantly better than in the large working space.
  
  
  CONCLUSIONS
  Single-port approaches were significantly more technically challenging than multiport approaches, possibly reflecting loss of instrument triangulation. Surprisingly, in single-port approaches, in which triangulation was no longer a factor, performance in large working spaces was worse than in intermediate and small working spaces.
authors.affiliation: Imperial College London, London, UK Imperial College Healthcare NHS Trust, London, UK hani.marcus10@imperial.ac.uk.
authors.forename: Hani J
authors.initials: HJ
authors.lastname: Marcus
authors.affiliation: Imperial College London, London, UK.
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Seneci
authors.affiliation: Imperial College London, London, UK.
authors.forename: Archie
authors.initials: A
authors.lastname: Hughes-Hallett
authors.affiliation: Imperial College London, London, UK.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Cundy
authors.affiliation: Imperial College Healthcare NHS Trust, London, UK.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Nandi
authors.affiliation: Imperial College London, London, UK.
authors.forename: Guang-Zhong
authors.initials: GZ
authors.lastname: Yang
authors.affiliation: Imperial College London, London, UK.
authors.forename: Ara
authors.initials: A
authors.lastname: Darzi
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: SILS; endoscopy; laparoscopy; minimally invasive surgery; single-incision laparoscopy; single-port surgery