title: Influence of instrument size on endoscopic task performance in pediatric intracorporeal knot tying: smaller instruments are better in infants.
abstract: BACKGROUND
  The widespread availability of adult minimal access surgical (MAS) equipment together with resource constraints have led pediatric surgeons to adopt the adult setup. This study examined the influence of instrument size on task outcome and physical impact on the surgeon in pediatric endoscopic intracorporeal knot tying.
  
  
  METHODS
  Sixteen surgeons participated in this study in which they had to tie surgeon's knots inside a neonatal simulator box with an endoscopic field of 40 mm. All surgeons tied 20 knots using paired pediatric needle-holders and 20 knots using paired adult needle-holders in a randomized order. Knot quality score (KQS) and wrap length were used as indices of knot quality and wrap tightness. Electromyographic (EMG) recordings of the upper limb muscle groups were used to indicate muscular recruitment. A questionnaire on discomfort and instrument preference was also completed by the surgeons.
  
  
  RESULTS
  A total of 640 knots were analyzed. Median time was shorter for pediatric needle-holders than for adult needle-holders (94 s vs. 103 s; p < 0.001); however, KQS (0.271 vs. 0.260; p = 0.509) and the tightness around the tube (86 mm vs. 86 mm; p = 0.255) were not significantly different. The proportion of knots that completely slipped was also similar for both needle-holders (19% vs. 22%; p = 0.322). The normalized EMG values when using adult needle-holders were significantly higher than when using pediatric needle-holders in all upper limb muscle groups with the exception of left forearm extensors (p = 0.460). The surgeons reported less discomfort with the pediatric needle-holders in the right forearm and hand, and 13 surgeons expressed overall preference for the smaller instruments.
  
  
  CONCLUSIONS
  Endoscopic knot tying was performed faster in the neonatal simulator box using pediatric needle-holders while maintaining knot quality. Upper limb muscular recruitment was reduced resulting in less discomfort for the surgeon.
authors.affiliation: Department of Biosurgery and Surgical Technology, Imperial College London, St Mary's Hospital, Praed Street, London, W2 1NY, UK.
authors.forename: Alex C H
authors.initials: AC
authors.lastname: Lee
authors.forename: Munther J
authors.initials: MJ
authors.lastname: Haddad
authors.forename: George B
authors.initials: GB
authors.lastname: Hanna
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology; D001696:Biomechanical Phenomena; D003258:Consumer Behavior; D019723:Endoscopes; D004724:Endoscopy / Q000379:methods*; D004867:Equipment Design; D005260:Female; D006225:Hand / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D010372:Pediatrics / Q000295:instrumentation* / Q000379:methods*; D013536:Suture Techniques / Q000295:instrumentation*; D013647:Task Performance and Analysis