Oral mechanical bowel preparation with Pico Salax (picosulfate sodium, magnesium oxide,
and citric acid) or alternative is considered a standard modality for cleansing the
entire colon prior to colonoscopy or surgical procedures. Fleet enemas are sodium
phosphate-based laxatives in the form of a liquid inserted rectally, which are also very
effective at evacuating the solid stool from the sigmoid and rectum in preparation for
procedures such as flexible sigmoidoscopy or anoscopy, which only require visualization
of the distal colon and rectum. Commonly, endoscopists use the well validated bowel
preparation scores such as the Boston Bowel Prep Score, Aronchick Scale or the Ottawa
Bowel Prep Scale when evaluating the effectiveness of such bowel preparation regimens at
clearing away all debris and opaque liquid from the colon. Few studies have been
performed to evaluate whether an oral mechanical bowel preparation or a rectal
application by means of fleet enemas or alternatives gives better visibility or is
preferred by the patient. A randomized controlled trial comparing two fleet enemas with
an oral preparation that consisted of magnesium citrate and two Dulcolax tablets for
flexible sigmoidoscopy, were able to show that patient acceptance, encounter time,
technical ease, quality of colon preparation was significantly better with the oral form
of colon preparation than with standard fleet enemas. On the other hand, another
randomized controlled trial were able to show that fleet enemas were superior to
picosulfate based oral bowel preparation for flexible sigmoidoscopy while also showing a
decreased incidence of associated adverse symptoms, and better patient tolerance.
Conflicting studies exist. Both bowel regimens are considered standard of care in
preparation for surgery of the sigmoid and rectum. Fleet enemas seem to be the
preparation most commonly used for flexible sigmoidoscopy.
Transanal endoscopic surgery (TES) is a minimally invasive technique used to perform full
thickness excisions of rectal lesions (benign and malignant) with precision, allowing
access to lesions in the rectum as high as 22 cm from the anus. The technique can be
performed using either the rigid transanal endoscopic microsurgery (TEM) platform or the
flexible port termed transanal endoscopic minimally invasive surgery (TAMIS). The
technique decreases risk of positive margins and local recurrence in comparison to
standard local excision techniques in the operating room. It is the preferred method of
local excision of rectal lesions. As with polyp detection and removal during flexible
sigmoidoscopy, TES for rectal neoplasms requires excellent visibility and minimization of
debris in order to be able to perform the precise excision of the lesion and help
facilitate closure of the full thickness defect in the rectal wall. TES is performed
globally with no consensus about the optimal bowel preparation regimen for achieving
visibility and facilitating the easiest, most efficient and safest dissection.
Objectives:
The primary objective of this study is to determine whether oral Pico Salax bowel
preparation regimen achieves a higher score on the Ottawa Bowel Prep Scale specifically
for the rectosigmoid segment in comparison to 2 fleet enemas during TES.
The secondary objectives include validation of the Ottawa Bowel Prep Scale specifically
for use with fleet enemas or Pico Salax for the rectosigmoid segment during TES;
determining if there are differences in length of time spent cleaning the operative field
by the surgeon; the ability to close the defect; post-operative short-term complications,
and patient tolerability of the preparation.
This study will serve as a pilot study for a potentially larger multi-center pan Canadian
RCT. The TEMPEST group is a collaboration of TES trained surgeons across Canada at
tertiary care teaching hospitals, involved in research collaborations. The results of
this study will be used to see if randomization to two different bowel regimens in this
very select group of patients undergoing trans-anal surgery is feasible and can yield
informative data. The study will be powered for the primary objective, but we will be
collecting data on numerous secondary objectives which may show important trends. If the
study proves to be feasible, the next step would be to expand the study to several other
centers across Canada as part of the TEMPEST collaborative, in order to collect much
larger datasets and the power to look much more closely at not only the primary objective
but also the secondary objectives.