Effectiveness of Stiffening Wire in Colonoscopy With Pre-Owned Colonoscopes

The study aims to determine whether a proprietary, FDA approved stiffening wire improves the efficiency of colonoscopy (that is, decreases the duration of the procedure) and/or enables complete visualization of the colon in a greater proportion of cases (than when the procedure is performed without it) with old, used colonoscopes.

Colonoscopes are designed with a delicate balance between stiffness and flexibility. Stiffness helps to prevent curling (looping) of the colonoscope in those sections of the colon that are not fixed to the wall of the abdominal cavity and flexibility enables successful negotiation of bends or flexures in the colon. As colonoscopes age, they lose stiffness and this makes it very challenging to advance the colonoscope all the way to the cecum (the upper end of the colon). Even when the cecum is successfully reached, it may take an inordinately long time.

In Jamaica, most endoscopists (General Surgeons and Gastroenterologists) use older, pre-owned colonoscopes imported from the USA, because the average patient and local health insurance companies cannot bear the level of fees that would enable cost recovery for new equipment.

The stiffening wires (in two grades of stiffness) used in this study are passed through the biopsy channel of the colonoscope only after its tip has passed the upper end of the descending colon and entered the transverse colon. The device is safe when used as recommended by the manufacturers (and approved by the FDA), and does not appear to increase risk over and above the risk of colonoscopy with the unassisted colonoscope. Although the device clearly improves the stiffness of the colonoscope, there is no research evidence that it actually works in practice, either to improve cecal intubation rate or to decrease procedure time. It is therefore also unclear whether the possible benefit of using the device is achieved if introduced at the first opportunity allowed by the manufacturers or only after difficulty is encountered with the unassisted colonoscope.

In this study, patients are randomly assigned to one of 3 "interventions". One group has colonoscopy performed with the colonoscope alone and the wires are only introduced if there is difficulty advancing the colonoscope after it has passed into the transverse colon ("difficulty" defined as failure to advance the tip of the colonoscope after 5 minutes). In the 2nd and 3rd groups, the assigned wire will be introduced as soon as the colonoscope enters the transverse colon and is removed if "difficulty" is encountered, as defined above. The different phases of colonoscopy will be timed with a stop watch and when a sufficient number of patients has been accrued, the investigator will be able to compare the time it takes to complete the procedure with and without the wires as well as the proportion of cases in which the cecum was reached with and without the assistance of the wires.

• Device: Colonoscope stiffening device
  Colonoscopy is performed with the unassisted colonoscope (Olympus CF-100TL). The "standard" stiffening wire is introduced only if there is difficulty advancing the colonoscope and only after the tip has passed the splenic flexure. Difficulty is defined as failure to advance the tip of the scope after 5 minutes of trying. If difficulty is again encountered, the "firm" wire replaces the "standard" wire. Further difficulty requires removal of the firm wire and so on until cecal intubation is achieved or the procedure is abandoned.
  Other Name: ZUTR-141700 (Standard) and ZUTR-161700 (Firm) by Zutron Medical
• Device: Colonoscope stiffening device
  "Standard" stiffening wire introduced routinely on entry into transverse colon. If difficulty is encountered (as defined previously), the "standard" wire is removed and attempts made to advance the colonoscope without it. Further difficulty requires introduction of the "firm" wire and so on until cecal intubation is achieved or the procedure is abandoned.
  Other Name: ZUTR-141700 (Standard) and ZUTR-161700 (Firm) by Zutron Medical
• Device: Colonoscope stiffening device
  "Firm" stiffening wire introduced routinely on entry into transverse colon. If difficulty is encountered (as defined previously), the wire is removed and attempts made to advance the colonoscope without it. Further difficulty requires introduction of the "standard" wire and so on until cecal intubation is achieved or the procedure is abandoned.
  Other Name: ZUTR-141700 (Standard) and ZUTR-161700 (Firm) by Zutron Medical

• Experimental: Stiffening wire only if difficulty
  Colonoscopy is performed with the unassisted colonoscope. The stiffening wire is introduced only if there is difficulty advancing the colonoscope and only after the tip has passed the splenic flexure. Difficulty is defined as failure to advance the tip of the scope after 5 minutes of trying.
  Intervention: Device: Colonoscope stiffening device
• Experimental: Stiffening wire #1 transverse colon
  Colonoscopy is started with the unassisted colonoscope. Stiffening wire #1 is introduced on entry of the tip of the colonoscope into the transverse colon.
  Intervention: Device: Colonoscope stiffening device
• Experimental: Stiffening wire #2 transverse colon
  Colonoscopy is started with the unassisted colonoscope. Stiffening wire #2 is introduced on entry of the tip of the colonoscope into the transverse colon.
  Intervention: Device: Colonoscope stiffening device

• Odori T, Goto H, Arisawa T, Niwa Y, Ohmiya N, Hayakawa T. Clinical results and development of variable-stiffness video colonoscopes. Endoscopy. 2001 Jan;33(1):65-9.
• Shah SG, Saunders BP. Aids to insertion: magnetic imaging, variable stiffness, and overtubes. Gastrointest Endosc Clin N Am. 2005 Oct;15(4):673-86. Review.
• Othman MO, Bradley AG, Choudhary A, Hoffman RM, Roy PK. Variable stiffness colonoscope versus regular adult colonoscope: meta-analysis of randomized controlled trials. Endoscopy. 2009 Jan;41(1):17-24. Epub 2009 Jan 21. Erratum in: Endoscopy. 2009 Apr;41(4):315.
• Baron TH. The variable stiffness colonoscope: a scope for all seasons? Am J Gastroenterol. 2002 Dec;97(12):2942-3. Review. No abstract available.
• East JM. Effect of a proprietary intraluminal stiffening wire device on cecal intubation time and rate with used colonoscopes; a randomized, controlled trial. BMC Res Notes. 2013 Feb 4;6:48. doi: 10.1186/1756-0500-6-48.

Inclusion Criteria:

• Adults 18 years and older having screening or diagnostic colonoscopy

Exclusion Criteria:

• Previous hysterectomy
• Previous radical prostatectomy
• Clinical presentation or imaging study suggesting presence of lesion that could obstruct passage of colonoscope