Page 40 - Flexible Robotics in Medicine

Prototyping soft origami quad-bellows robots from single-bellows characterization 23

the common path undertaken by the scope tends to miss certain areas of the colon due to
the visualization limitation of the endoscope [16].

One study found that female subjects tend to have a brachymesocholic sigmoid mesocolon
due to the anatomically wider hips in females [17]. Another study also supported this
and found that the total colonic length tends to be longer in females, especially for the
transverse colon that resulted from a broader colon [18]. Some studies also showed that the
sigmoid colon was longer in females [12]. These findings support multiple studies showing
anatomical differences between the sexes, such as how a deeper pelvis and less muscular
abdominal walls in females compared to makes can contribute to more looping in the colon,
which correlates to a higher difficulty of the procedure [18].
The sigmoid colon exhibited variation, as observed from the high standard deviation of the
reported results, especially in terms of the length [17]. It is difficult to determine a standard
methodology, as different studies segmented the various sections of the colon differently.
The sigmoid colon is the segment of the colon that is the smallest in diameter [19]. There
are variances in the mobility and anatomical measurements of the colon among people of
different ethnicities [20]. Thus we take the internal diameter of the sigmoid colon to be
3 cm.
According to studies on colonoscopy, trainees mainly improve through practice rather than
theoretical learning. Success rates can stabilize above 90% once trainees have conducted
around 250 or more procedures. In cases of failure to intubate the cecum by trainees, a
high percentage of cases saw successful reinsertion after experienced persons intervened,
indicating that the success rate of the colonoscopy is more due to technical proficiency
than existing complications of the patients’ colon anatomy [21].

There are a variety of techniques employed in using the colonoscope that is required for
the physician to be able to navigate and scope the colon [14] successfully. Advanced
techniques are essential for the physician to resolve issues of looping caused by the
procedure. Jiggling and shaking are commonly used to re-center the viewing tip of the
colonoscope and prevent the colon walls from sticking to the shaft; this helps to straighten
and shorten the colon. The right/left turn shortening and hooking techniques are standard
after passing a junction to resolve a loop formation of the colon by pulling the previous
tortuous segment straight. Besides the above-explained techniques, which are essential in
ensuring successful colonoscopy without extensive looping, the slide-by technique is an
advanced technique that requires a high level of skill to execute successfully without the
occurrence of iatrogenic perforation that can lead to further complications such as
hemorrhage.

Considering the areas within the colon which pose difficulties for an efficient colonoscopy,
successful navigation through the rectosigmoid junction was indicative of a successful