The variable stiffness colonoscope is a tool that combines the flexibility of pediatric instruments for negotiation of the sigmoid colon with the ability to stiffen the insertion tube. This can be done to prevent or control looping after straightening.
Dr Syed G. Shah and colleagues from the Wolfson Unit for Endoscopy at St. Mark's Hospital in London, England, carried out 2 studies into the stiffening device.
In the first study, the research group investigated the effect of routinely stiffening the straightened variable stiffness colonoscope in the mid-descending colon of 82 patients.
A total of 2 insertions were performed (mid-colon to cecum) in each patient, with and without application of the stiffening device, in a randomized manner.
For each insertion, the length of time and number of ancillary maneuvers required to negotiate certain parts of the colon with the colonoscope were noted.
These maneuvers included directing the variable-stiffness colonoscope along the proximal colon, passing it across the splenic flexure into the transverse colon and passing the right colon.
The second study involved examination of consecutive patients using a standard adult variable-stiffness colonoscope.
| Variable-stiffness device:|
- Controlled looping of the colonoscope 57% of the time
| Gastrointestinal Endoscopy|
Patients with previous colon resection were excluded from this study group.
Real-time views of the procedure with magnetic endoscope imaging were recorded for all examinations, but procedures were randomized to be done either with
(n = 88), or without (n = 87), the endoscopist viewing the magnetic endoscope imaging display.
Whenever stiffening was applied, a note was made of the anatomic location of the colonoscope tip and the stiffness efficacy.
In study 1, time taken to negotiate the proximal colon and the splenic flexure were significantly shorter and ancillary maneuvers performed were fewer with the stiffening device activated.
In study 2, stiffening was used with similar frequency in patients examined with and without the magnetic endoscope imaging view, most commonly for passing the splenic flexure (71%), but also in the transverse colon (12%), right colon (9%), and sigmoid/descending colon (8%).
Stiffening was significantly more effective when used in combination with magnetic endoscope imaging (69% with imager compared to 45% without imager).
Overall, the variable-stiffness device used was effective in controlling looping 57% of the time.
"Activating maximum stiffness appears to be effective once the sigmoid colon has been negotiated and the colonoscope straightened with the tip in the proximal colon, reducing the number of ancillary maneuvers and shortening the insertion time through the proximal colon", said Dr Shah.
He added, "Routine magnetic endoscope imaging further enhances the efficacy of the variable-stiffness colonoscopes by helping to identify the optimal time for stiffening."