title: Interactive navigation-guided ophthalmic plastic surgery: navigation enabling of telescopes and their use in endoscopic lacrimal surgeries.
abstract: OBJECTIVE
  The aims of this study were to report the preliminary experience of using telescopes, which were enabled for navigation guidance, and their utility in complex endoscopic lacrimal surgeries.
  
  
  METHODS
  Navigation enabling of the telescope was achieved by using the AxiEM™ malleable neuronavigation shunt stylet. Image-guided dacryolocalization was performed in five patients using the intraoperative image-guided StealthStation™ system in the electromagnetic mode. The "look ahead" protocol software was used to assist the surgeon in assessing the intraoperative geometric location of the endoscope and what lies ahead in real time. All patients underwent navigation-guided powered endoscopic dacryocystorhinostomy. The utility of uninterrupted navigation guidance throughout the surgery with the endoscope as the navigating tool was noted.
  
  
  RESULTS
  Intraoperative geometric localization of the lacrimal sac and the nasolacrimal duct could be easily deciphered. Constant orientation of the lacrimal drainage system and the peri-lacrimal anatomy was possible without the need for repeated point localizations throughout the surgery. The "look ahead" features could accurately alert the surgeon of anatomical structures that exists at 5, 10 and 15 mm in front of the endoscope. Good securing of the shunt stylet with the telescope was found to be essential for constant and accurate navigation.
  
  
  CONCLUSIONS
  Navigation-enabled endoscopes provide the surgeon with the advantage of sustained stereotactic anatomical awareness at all times during the surgery.
authors.affiliation: The Institute of Dacryology.
authors.forename: Mohammad Javed
authors.initials: MJ
authors.lastname: Ali
authors.affiliation: The Institute of Dacryology.
authors.forename: Swati
authors.initials: S
authors.lastname: Singh
authors.affiliation: The Institute of Dacryology.
authors.forename: Milind N
authors.initials: MN
authors.lastname: Naik
authors.affiliation: The Operation Eyesight Universal Institute for Eye Cancer, L.V. Prasad Eye Institute, Hyderabad, India.
authors.forename: Swathi
authors.initials: S
authors.lastname: Kaliki
authors.affiliation: The Institute of Dacryology.
authors.forename: Tarjani Vivek
authors.initials: TV
authors.lastname: Dave
keywords: endoscope; image guidance; lacrimal surgery; navigation; powered endoscopic DCR; telescope