title: Multidirectional projectional rigid neuro-endoscopy: prototype and initial experience.
abstract: BACKGROUND
  The role of neuro-endoscopy is emerging. Traditional endoscopy is complicated by limited 2D views that make surgical interventions difficult. We have developed a rigid endoscope with a variable direction view that provides 3D visualization.
  
  
  METHODS
  A prototype of the EndActive endoscope was used to examine 2 brain/intraventricular models. A 360-degree view is controlled via integrated joystick. Alternatively, the computer can volumetrically capture the ventricular surface. The captured video image can be viewed later or processed to create a flat projection map. The performance of this endoscope was compared to standard endoscopy with fixed directions of view. To simulate endoscopy, the center of the first brain model had eight labeled projections. The model was inspected with the multidirectional endoscope, standard rigid endoscopes (0-, 30- and 70-degree), and via a projection map. Ten neurosurgeons proficient in neuro-endoscopy were recruited for the experiments. The second brain model was labeled with 32 intraventricular tumors.
  
  
  RESULTS
  With a 0-degree endoscope, only the number directly opposite the site of entry was visualized. With increasing angles, additional numbers were visualized. The 70-degree endoscope allowed 4 of 8 numbers to be visualized. Using the multidirectional endoscope, all 8 numbers were visualized. The multidirectional endoscope was more accurate in identifying markers compared to standard endoscopy (p = 0.031). The mean endoscopy times using the multidirectional endoscope and standard endoscopy were 143 and 117 seconds, respectively (p = 0.243). The best performance was obtained when the flat projection map was read (p < 0.01). Using the endoscope prototype, an average of 30.8 (96%) tumors was identified on the brain model.
  
  
  CONCLUSIONS
  The EndActive endoscope is a rigid endoscope that provides complete visualization of a 3D space by controlling an adjustable viewing direction. In our study, the multidirectional endoscope provided superior visualization compared to standard endoscopy.
authors.affiliation: Division of Neurosurgery, University of California, San Diego, California 92103-8893, USA. hearyan@ucsd.edu
authors.forename: H E
authors.initials: HE
authors.lastname: Aryan
authors.forename: H D
authors.initials: HD
authors.lastname: Hoeg
authors.forename: L F
authors.initials: LF
authors.lastname: Marshall
authors.forename: M L
authors.initials: ML
authors.lastname: Levy
mesh_terms: D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation* / Q000379:methods; D008953:Models, Anatomic; D044582:Neuroendoscopes; D044583:Neuroendoscopy / Q000379:methods*; D019635:Neurosurgical Procedures / Q000295:instrumentation* / Q000379:methods; D020535:Video-Assisted Surgery / Q000295:instrumentation / Q000379:methods