CathCam Guide Wire-Directed Colonoscopy: First Pilot Study in Patients with a Previous Incomplete Colonoscopy

Background and Study Aims: Conventional colonoscopy as the gold standard for large-bowel diagnostics and therapy may fail in 5 % - 20 % of cases, depending on the experience of the examiner. Colonoscopy is regarded as difficult and painful by many patients. In an attempt to overcome the limitations of conventional colonoscopes, a guide wire-directed, thin, flexible diagnostic colonoscope, the CathCam was developed. In this prospective pilot study, we report its use in patients in whom conventional colonoscopy had failed.
Patients and Methods: 49 patients with a previous or current failure of complete colonoscopy were invited to participate in a trial using the new CathCam system, and 14 (nine men; mean age 59 years) accepted. The CathCam is an 11-mm diameter disposable, multilumen catheter, with visualization by a 3-mm camera with six light-emitting diodes. In the first five patients, the CathCam was inserted over a newly developed 0.024-inch, hinged, lumen-seeking guide wire. Subsequently, a modified combined approach was used: a conventional colonoscope was introduced into the sigmoid or left colon, then the guide wire was advanced as far as possible, followed by CathCam insertion over it. Caecal intubation rate, insertion times and patient discomfort were recorded; patients received low-dose midazolam sedation (2 - 5 mg).
Results: One patient was excluded during colonoscopy. The caecum could be eventually reached in 12 of 13 patients; in the remaining patient a significant sigmoid stricture could be passed, but further advancement appeared too risky. The mean caecal intubation time was 24 minutes (range 3 - 105 min). Only two patients experienced pain and discomfort during the procedure (one immediate assessment and one case reported at later telephone interview). No complications occurred, and previously undiagnosed important findings were obtained in 9 cases.
Conclusions: A combined approach, consisting of guide wire insertion via a partially introduced colonoscope followed by CathCam or colonoscope insertion into the caecum was successful in over 90 % of patients with previous failure of complete colonoscopy. Further improvements may make this system suitable for use as a standard diagnostic colonoscope, either as a single unit (CathCam plus guide wire) or using the guide wire alone with a standard colonoscope in difficult cases.

References

• 1 Cotton P B, Connor P, McGee D, Jowell P. et al . Colonoscopy: practice variation among 69 hospital-based endoscopists.  Gastrointest Endosc. 2003;  57 352-357
• 2 Bowles C JA, Leicester R, Romaya C. et al . A prospective study of colonoscopy practice in the UK today: are we adequately prepared for national colorectal cancer screening tomorrow?.  Gut. 2004;  53 277-283
• 3 Zuo Jm Yan G, Gao Z. A micro creeping robot for colonoscopy based on the earthworm.  J Med Eng Technol. 2005;  29 1-7
• 4 Asari K V, Kumar S, Kassim I M. A fully autonomous microrobotic endoscopy system.  J Intelligent Robotic Systems Netherlands. 2000;  28 325-341.
• 5 Takada M. Self propelled colonoscope. US patent 5,562,601 1996
• 6 Raju G S, Pasricha P J. ShapeLock: a rapid access port for redeployment of a colonoscope into the proximal colon to facilitate multiple polypectomies in a single session.  Gastrointest Endosc. 2005;  61 768-770
• 7 Raju G S, Rex D K, Kozarek R A. et al . A novel shape-locking guide for prevention of sigmoid looping during colonoscopy.  Gastrointest Endosc. 2004;  59 416-419
• 8 Dario P, Carrozza M C, Pietrabissa A. Development and in vitro testing of a miniature robotic system for computer-assisted colonoscopy.  Comput Aided Surg. 1999;  4 1-14
• 9 Swain P, Fritscher-Ravens A, Mylonaki M. Experimental and clinical studies of wireless capsule colonoscopy.  Gastrointest Endosc. 2004;  59 AB103
• 10 Long G, Swain C P, Fritscher-Ravens A. The CathCam. A new type of colonoscope.  Gut. 2004;  53 (Suppl. IV) A52
• 11 Long G, Swain C P, Fritscher-Ravens A. The development of guide wires for colonoscopy: double wires, loops, hinges for tip propulsion methods.  Gut. 2004;  53 (Suppl. IV) A82