title: Light sources for single-access surgery.
abstract: BACKGROUND
  Minimally invasive surgical techniques such as single access and natural orifice translumenal endoscopic surgery (NOTES) aim to reduce the number of external scars on the patient but impose restrictions on the space available for the light source within the endoscope and, therefore, the size of the field of view that can be sufficiently illuminated.
  
  
  METHODS
  This article presents and compares a number of illumination methods (xenon, light-emitting diodes, laser/phosphor, supercontinuum laser) that could be applied in single-access, robotic, and NOTES procedures. The luminance, spectral content, and intensity profile of each source was measured. Standardized images of each illuminating an abdominal simulator were assessed by a group of surgeons to provide an initial clinical impression.
  
  
  RESULTS
  The xenon source was found to have the highest luminance when used with a standard laparoscopic light cable, but this was significantly reduced when used with a small cable suitable for single-access applications. The supercontinuum laser-based light source had brightness comparable to the xenon, which was supported by the surgical test group observations.
  
  
  CONCLUSIONS
  The supercontinuum fiber probe is a potential alternative to xenon light sources for use in single-access surgery with its comparable luminance, small diameter, flexibility, and even illumination. An initial in vivo test is described, providing a guide for future development.
authors.affiliation: Imperial College London, London, UK. n.clancy@imperial.ac.uk
authors.forename: Neil T
authors.initials: NT
authors.lastname: Clancy
authors.forename: James
authors.initials: J
authors.lastname: Clark
authors.forename: David P
authors.initials: DP
authors.lastname: Noonan
authors.forename: Guang-Zhong
authors.initials: GZ
authors.lastname: Yang
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Elson
mesh_terms: D000818:Animals; D003116:Color; D019723:Endoscopes; D004724:Endoscopy / Q000295:instrumentation*; D010535:Laparoscopy / Q000295:instrumentation*; D007834:Lasers; D008029:Lighting / Q000295:instrumentation*; D008954:Models, Biological; D012371:Robotics / Q000295:instrumentation; D013057:Spectrum Analysis; D013552:Swine; D014978:Xenon
chemical_list: D014978:Xenon