title: Current state of micro-robots/devices as substitutes for screening colonoscopy: assessment based on technology readiness levels.
abstract: BACKGROUND
  Previous reports have described several candidates, which have the potential to replace colonoscopy, but to date, there is still no device capable of fully replacing flexible colonoscopy in the management of colonic disorders and for mass adult population screening for asymptomatic colorectal cancer.
  
  
  METHODS
  NASA developed the TRL methodology to describe and define the stages of development before use and marketing of any device. The definitions of the TRLS used in the present review are those formulated by "The US Department of Defense Technology Readiness Assessment Guidance" but adapted to micro-robots for colonoscopy. All the devices included are reported in scientific literature. They were identified by a systematic search in Web of Science, PubMed and IEEE Xplore amongst other sources. Devices that clearly lack the potential for full replacement of flexible colonoscopy were excluded.
  The technological salient features of all the devices included for assessment are described briefly, with particular focus on device propulsion. The devices are classified according to the TRL criteria based on the reported information. An analysis is next undertaken of the characteristics and salient features of the devices included in the review: wireless/tethered devices, data storage-transmission and navigation, additional functionality, residual technology challenges and clinical and socio-economical needs.
  
  
  CONCLUSIONS
  Few devices currently possess the required functionality and performance to replace the conventional colonoscopy. The requirements, including functionalities which favour the development of a micro-robot platform to replace colonoscopy, are highlighted.
authors.affiliation: Surgical Technology and Robotics Group, Institute for Medical Science and Technology (IMSaT), University of Dundee, Dundee, DD2 1FD, UK.
authors.forename: Silvia C
authors.initials: SC
authors.lastname: Tapia-Siles
authors.affiliation: Surgical Technology and Robotics Group, Institute for Medical Science and Technology (IMSaT), University of Dundee, Dundee, DD2 1FD, UK.
authors.forename: Stuart
authors.initials: S
authors.lastname: Coleman
authors.affiliation: Surgical Technology and Robotics Group, Institute for Medical Science and Technology (IMSaT), University of Dundee, Dundee, DD2 1FD, UK. a.cuschieri@dundee.ac.uk.
authors.forename: Alfred
authors.initials: A
authors.lastname: Cuschieri
mesh_terms: D000328:Adult; D003113:Colonoscopy / Q000295:instrumentation / Q000639:trends; D015179:Colorectal Neoplasms / Q000473:pathology*; D004059:Diffusion of Innovation; D055088:Early Detection of Cancer; D004867:Equipment Design; D006801:Humans; D008403:Mass Screening / Q000379:methods* / Q000639:trends; D036103:Nanotechnology; D065287:Robotic Surgical Procedures / Q000295:instrumentation* / Q000639:trends; D012371:Robotics / Q000295:instrumentation / Q000639:trends*; D013673:Technology Assessment, Biomedical; D014481:United States / Q000453:epidemiology; D018557:United States National Aeronautics and Space Administration
keywords: Colonic locomotion; Colonoscopy; Medical robotics; Micro-robot; Technology readiness level