title: Tortuous iliac systems--a significant burden to conventional cannulation in the visceral segment: is there a role for robotic catheter technology?
abstract: OBJECTIVE
  To attempt to quantify the effect of varying degrees of iliac tortuosity on maneuverability and "torquability" of endovascular catheters in the visceral segment, comparing conventional and robotic cannulation techniques.
  
  
  METHODS
  In a fenestrated endograft within a pulsatile phantom, 10 experienced operators cannulated the renal arteries via three different access vessels of varying iliac tortuosity with the use of conventional and robotic techniques. All procedures were performed in the angiography suite and recorded for blinded video assessment for quantitative (time, catheter-tip movements) and qualitative metrics (operator performance scores).
  
  
  RESULTS
  In total, 120 cannulations were observed. With increasing iliac tortuosity, median time and number of catheter movements required for renal cannulation with conventional techniques increased in stepwise fashion for mild, moderate, and severe iliac tortuosity (times, 7.6 min [interquartile range (IQR), 4.6-9.3 min] vs 6.9 min [4.2-11.4 min] vs 17.7 min [13.3-22.6 min], respectively; movements, 184 [IQR, 110-351] vs 251 [207-395] vs 569 [409-616], respectively). Median renal cannulation times were significantly reduced with the use of the robotic system irrespective of mild, moderate, or severe tortuosity (times, 1.4 min [IQR, 1.1-1.9 min] vs 3 min [2.3-3.3 min] vs 2.8 min [1.5-3.9 min], respectively; movements, 19 [IQR, 14-27] vs 46 [43-58] vs 45 [40-66], respectively; P < .005). Overall operator performance scores improved significantly with the use of the robotic system irrespective of iliac tortuosity severity.
  
  
  CONCLUSIONS
  In cases of moderate to severe iliac tortuosity, conventional catheter manipulation and control becomes an issue. The improvement in positional control and predictability seen with advanced catheter designs may be amplified in cases of severe iliac tortuosity.
authors.affiliation: Regional Vascular Unit, Imperial College Healthcare, St Mary's Hospital, London, United Kingdom. c.riga@imperial.ac.uk
authors.forename: Celia V
authors.initials: CV
authors.lastname: Riga
authors.forename: Colin D
authors.initials: CD
authors.lastname: Bicknell
authors.forename: Mohamad
authors.initials: M
authors.lastname: Hamady
authors.forename: Nicholas
authors.initials: N
authors.lastname: Cheshire
mesh_terms: D017545:Aortic Aneurysm, Thoracic / Q000000981:diagnostic imaging / Q000628:therapy*; D002406:Catheterization, Peripheral / Q000295:instrumentation / Q000379:methods*; D002983:Clinical Competence; D057510:Endovascular Procedures / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging; D059032:Learning Curve; D019047:Phantoms, Imaging; D015641:Radiography, Interventional; D012077:Renal Artery / Q000000981:diagnostic imaging; D012371:Robotics / Q000295:instrumentation; D013647:Task Performance and Analysis; D013813:Therapy, Computer-Assisted / Q000295:instrumentation; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000295:instrumentation; D019415:Torque; D062666:Vascular Access Devices; D014741:Video Recording