Preoperative factors predictive of permanent stoma creation were investigated in a long-term follow-up of patients with mid or low rectal cancer.

We included patients who underwent radical resection for mid or low rectal cancer with available data for preoperative anal function measured by manometry and Faecal Incontinence Severity Index questionnaire between January 2005 and December 2015 in three tertiary referral hospitals. A permanent stoma was defined as a stoma present until the patient's last follow-up visit or death. Preoperative factors that predicted permanent stoma creation were analysed.

Over a median follow-up of 57.4 months (range 12-143 months), a permanent stoma was created in 144/577 (25.0%) patients, including 89 (15.4%) who underwent abdominoperineal resection, one (0.2%) who underwent Hartmann's operation without reversal, 15 (2.6%) with a diverting ileostomy at the time of initial sphincter-preserving surgery without undergoing stoma reversal, and 39 (6.8%) who underwent permanent ileostomy formation after sphincter-preserving surgery. Patients with permanent stoma creation had a shorter tumour distance from the anal verge (P < 0.001), larger tumour size (P = 0.020) and higher preoperative Faecal Incontinence Severity Index score (P = 0.020). On multivariable analysis, tumour distance from the anal verge predicted permanent stoma formation (relative risk 0.53 per centimetre increase; 95% confidence interval 0.46-0.60; P < 0.001) but preoperative anal function did not.

Tumour distance from the anal verge was the only preoperative determinant of permanent stoma creation in rectal cancer patients. These data may help mid and low rectal cancer patients understand the need for permanent stoma.

Despite a high incidence of fecal incontinence following sphincter-preservation surgery (SPS), there are no definitive factors measured before ileostomy reversal that predict fecal incontinence. We investigated whether vector volume anorectal manometry before ileostomy reversal predicts major fecal incontinence following SPS in patients with mid or low rectal cancer.

This longitudinal prospective cohort study comprised 173 patients who underwent vector volume anorectal manometry before ileostomy reversal. The Fecal Incontinence Severity Index was measured 1 year after the primary SPS and classified as major incontinence (FISI score ≥ 25) or continent/minor incontinence (FISI score < 25). Multivariable logistic regression analysis was used to identify predictors of major incontinence.

Ninety-two patients (53.1%) had major incontinence. Although tumor stage, location, and neoadjuvant chemoradiotherapy were comparable, the major incontinence group had lower resting pressure (28.4 vs. 34.3 mmHg, P = 0.027), greater asymmetry at rest (39.1% vs. 34.1%, P = 0.002) and squeezing (34.2% vs. 31.4%, P = 0.046), shorter sphincter length (3.3 vs. 3.7 cm, P = 0.034), and lower resting vector volume (143,601 vs. 278,922 mmHg² mm, P < 0.001) compared with the continent/minor incontinence group. Resting vector volume was the only independent predictor of major incontinence (odds ratio = 0.675 per 100,000 mmHg² mm, 95% confidence interval, 0.532-0.823; P = 0.006).

This study revealed that resting vector volume before ileostomy reversal may predict major fecal incontinence. We suggest that the physiology of the anorectum should be discussed with patients before ileostomy reversal in patients at high risk of fecal incontinence.

Variability in functional outcome after ileal pouch-anal anastomosis (IPAA) is to a large extent unexplained. The aim of this study was to use MRI to evaluate the morphology, emptying pattern and other pathology that may explain differences in functional outcome between well-functioning and poorly functioning pouch patients. A secondary aim was to establish a reference of normal MRI findings in pelvic pouch patients.

From a previous study, the best and worst functioning patients undergoing IPAA surgery between 2000 and 2013 had been identified and examined with manovolumetric tests (N = 47). The patients were invited to do a pelvic MRI investigating pouch morphology and emptying patterns, followed by a pouch endoscopy.

Forty-three patients underwent MRI examination. We found no significant morphological or dynamic differences between the well-functioning and poorly functioning pouch patients. There was no correlation between urge volume and the volume of the bony pelvis, and no correlation between emptying difficulties or leakage and dynamic MRI findings. Morphological MRI signs of inflammation were present in the majority of patients and were not correlated to histological signs of inflammation. Of the radiological signs of inflammation, only pouch wall thickness correlated to endoscopic pouchitis disease activity index scores.

It seems MRI does not increase the understanding of factors contributing to functional outcome after ileal pouch-anal anastomosis. Unless there is a clinical suspicion of perianal/peripouch disease or pelvic sepsis, MRI does not add value as a diagnostic tool for pelvic pouch patients. Endoscopy remains the golden standard for diagnosing pouch inflammation.

To investigate the changes of postoperative anal sphincter function and bowel frequency in Korean patients with ulcerative colitis (UC).

A total of 127 patients with UC who underwent restorative proctocolectomy (RPC) during 20 years were retrospectively analyzed. The parameters of anal manometry and bowel frequency were compared according to the 6-mo intervals until 24 mo postoperatively. Manometry was used to measure the maximal squeezing pressure (MSP) and maximal resting pressure (MRP).

MSP decreased after surgery until 6 mo (157 to 142 mmHg); thereafter, it improved and was recovered to and maintained at the preoperative value at 12 mo postoperatively (142-170 mmHg, P < 0.001). Although the decreased MRP (65 to 56 mmHg) improved after 18 mo (62 mmHg), it did not completely recover to the preoperative value. The decreased rectal capacity after surgery (90 to 82 mL) gradually increased up to 150 mL at 24 mo. Although bowel frequency showed significant gradual decreases at each interval, it was stabilized after 12 mo postoperatively (6.5 times/d).

Postoperative changes of manometry and bowel frequency after restorative proctocolectomy in Korean patients with UC were not different from those in Western patients with UC.

Anal manometry is routinely used in the assessment of the anal sphincters in patients with fecal incontinence or suspected sphincter injury. Such physiological information is complementary to the anatomical assessment provided by anal endosonography. The evolution of 3-dimensional anal endosonography provides more diagnostically useful information in complex cases. Vector volume manometry has been developed to give a 3-dimensional view of the anal sphincters.

We reviewed the published literature on this technique, with the intention of deriving a system of standardization based on the published literature and to summarize the derivation and physiological meaning of the parameters measurable by vector volume studies, as well.

We undertook a MEDLINE search using the terms "vector volume" or "vector manometry" and "anal canal." We also reviewed further publications found from references cited in the original articles identified from the above search.

Only English language articles of studies performed on humans were reviewed.

Anal canal vector volume manometry was the intervention.

With the development of automated puller systems and associated software, parameters such as total vector volume, maximum pressure, mean pressure, anal canal symmetry, anal canal length, and the length of the high-pressure zone can be readily calculated.

There are conflicting studies related to the clinical value of both anal manometry and vector volume manometry, in part, because of the lack of standardization of equipment and technique.

The vector volume parameters have been shown to correlate with both imaging results and incontinence scores with automated puller systems. The clinical utility of vector volume manometry would be improved further by the standardization of equipment and technique. The main clinical utility may lie in the treatment selection and preoperative assessment of patients awaiting surgery for anal pathology that has yet to be evaluated.

The aim of this animal study was to investigate the effect of intraoperative pelvic nerve stimulation on internal anal sphincter electromyographic signals in order to evaluate its possible use for neuromonitoring during nerve-sparing pelvic surgery.

Eight pigs underwent low anterior rectal resection. The intersphincteric space was exposed, and the internal (IAS) and external anal sphincter (EAS) were identified. Electromyography of both sphincters was performed with bipolar needle electrodes. Intermittent bipolar electric stimulation of the inferior hypogastric plexus and the pelvic splanchnic nerves was carried out bilaterally. The recorded signals were analyzed in its frequency spectrum.

In all animals, electromyographic recordings of IAS and EAS were successful. Intraoperative nerve stimulation resulted in a sudden amplitude increase in the time-based electromyographic signals of IAS (1.0 (0.5-9.0) μV vs. 4.0 (1.0-113.0) μV) and EAS (p < 0.001). The frequency spectrum of IAS in the resting state ranged from 0.15 to 5 Hz with highest activity in median at 0.77 Hz (46 cycles/min). Pelvic nerve stimulation resulted in an extended spectrum ranging from 0.15 to 20 Hz. EAS signals showed higher frequencies mainly in a range of 50 to 350 Hz. However, after muscle relaxation with pancuronium bromide, only the low frequency spectrum of the IAS signals was still present.

Intraoperative verification of IAS function by stimulation of pelvic autonomic nerves is possible. The IAS electromyographic response could be used to monitor pelvic autonomic nerve preservation.

Restorative proctectomy with straight coloanal anastomosis (CAA) and restorative proctocolectomy with ilealpouch-anal anastomosis (IPAA) are options for maintaining bowel integrity after rectal resection. The aim of this study was to compare clinical function and anorectal physiology in patients treated with CAA and IPAA.

Three-dimensional vector-manometry and neorectal volumetry were performed in straight CAA [53 patients (34 male)] and IPAA [61 patients (39 male)] for ulcerative colitis. Function was assessed using a 14 day incontinence diary.

Function was similar in both groups, but neorectal compliance and threshold volumes for sensation, urge and maximum tolerated volume (MTV) were significantly higher after IPAA than after CAA. Mean pressure, vector volume and sphincter symmetry at rest were significant determinants of continence in both groups but squeeze pressure did not correlate significantly with function in either group. Threshold volume, MTV, and compliance were significantly correlated with frequency of defecation in patients with IPAA but not with CAA.

A strong consistent resting anal sphincter pressure is one determinant of continence after both IPAA and CAA. Squeeze pressures do not influence the functional result. In IPAA but not CAA, the neorectum has a reservoir function which correlates with the postoperative frequency of defaecation.

Ileal pouch anal anastomosis is an established option for patients who require total proctocolectomy and restoration of bowel continuity. However, the functional results are not always good and low pouch compliance has been suggested as one possible cause. We aimed to review the results of pouch compliance tests over 11 years to assess whether measuring pouch compliance is a useful diagnostic tool to guide management of pouch dysfunction.

The results of pouch compliance tests performed between 1996 and 2007 together with the details of symptoms, treatments and outcome were reviewed.

One hundred and forty-one pouch compliance tests were performed. There was no difference in pouch compliance between those with overt pathology (pouchitis, pelvic sepsis or anastomotic stricture) and those with idiopathic pouch dysfunction. In this second group, there was no difference in pouch compliance between patients with and without each of the symptoms of increased defaecatory frequency, incontinence and evacuation difficulties. The results of the compliance testing did not influence the clinical decision making on idiopathic pouch dysfunction (p=0.77) nor diverted pouches (p=0.07).

Measuring pouch compliance does not offer new information accounting for idiopathic pouch dysfunction and has little influence on the clinical management.

The technique of rectal dissection during restorative proctocolectomy might influence the rate of septic complications. The aim of this study was to analyze the morbidity of restorative proctocolectomy in a consecutive series of patients who had rectal dissection with complete preservation of the mesorectum.

One hundred thirty-one patients who had restorative proctocolectomy for chronic inflammatory bowel disease with handsewn ileopouch-anal anastomosis (IPAA) and preservation of the mesorectal tissue were analyzed by chart reviews and a follow-up investigation at a median of 85 (14-169) months after surgery.

Only one of 131 patients had a leak from the IPAA, and one patient had a pelvic abscess without evidence of leakage, resulting in 1.5% local septic complications. All other complications including the pouch failure rate (7.6%) and the incidence of both fistula (6.4%) and pouchitis (47.9%) were comparable to the data from the literature.

The low incidence of local septic complications in this series might at least in part result from the preservation of the mesorectum. As most studies do not specify the technique of rectal dissection, this theory cannot be verified by an analysis of the literature and needs further approval by a randomized trial.