There is no consensus about the best bowel preparation prior to transanal endoscopic surgery TES). Cleanliness and visibility in the rectosigmoid and rectum are of utmost importance, possibly even more so than during colonoscopy, to facilitate safe, precise and efficient resection of the rectal lesion and potentially adequate closure of the defect. Both Fleet enemas and oral mechanical bowel preparation are considered standard of care in preparation for TES. This single center two arm single blinded randomized controlled trial will compare the effectiveness of Fleet enemas in comparison to Pico Salax oral mechanical bowel preparation in cleansing the rectum as measured by a modified version of the Ottawa Bowel Prep Scale.

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.

Inclusion Criteria:

• undergoing transanal endoscopic surgery at the QEII Health Sciences Center in Halifax by one of the colorectal trained surgeons

Exclusion Criteria:

• chronic constipation not well controlled with diet or stool softening agents
• previous pelvic radiation
• inflammatory bowel disease
• repeat transanal surgery for the same lesion
• patient unable to self-administer enemas
• patient unable to tolerate either of the 2 bowel preps due to medical reasons
• age over 75
• clear diagnosis of congestive heart failure
• daily use of Lasix or similar loop diuretic
• chronic steroid use
• Transanal Endoscopic Surgery combined with another surgical procedure

The participant will receive information pertaining to which arm of the trial they have been randomized to by the research coordinator. The surgeons, residents, any other physicians involved in the care of the patient, and nursing staff will all be blinded to the treatment arm.