Obstructive defaecation syndrome (ODS) includes a spectrum of abnormal evacuation symptoms such as straining, incomplete emptying, repetitive toilets visit. ODS primarily develop via maladaptive pelvic floor coordination during defaecation. Anatomical abnormalities (such as pelvic floor descent and rectocoeles) can coexist and being primary or secondary to this. 
In terms of patients’ management, conservative approach should be the first line management while surgery might indicated only when anatomical defects are present and patients haven’t achieved satisfactory improvements.  The aim of the study was to review our cohort of patients presenting with ODS and establish predictors of success for ODS treatment, based on initial assessment using demographic, validated questionnaires and tests.

A retrospective review of prospectively collected data was performed for patients presenting to a tertiary referral pelvic floor unit for the assessment of ODS over a period of 4 years (2013-2017). All patients underwent a dedicated telephone triage assessment clinic (TTAC), where symptoms severity scores were assessed and completed using Obstructive defaecation score (ODS), ICIQ-BS (International Consultation on Incontinence Modular Questionnaire-Bowel Symptoms), St Mark’s faecal incontinence grading system and Bristol stool chart. Obstructive defaecation syndrome (ODS) has been assessed using the main symptom reported from patients and evaluating scores from different questionnaires used. 
The following tests have been done:
1.	Station pull-through anal manometry with a water-perfused catheter system. This provided measurements of anal resting tone (lower limit of normal 50 cmH2O) an anal squeeze increment pressures (lower limit of normal 50 cmH2O). 
2.	Assessment of rectal sensation. Three sensory thresholds were determined via ramp distension of a latex balloon positioned 10 cm from the anal verge: threshold volume (upper limit of normal, 150 mL); defaecatory desire volume (upper limit of normal, 190 mL); and maximum tolerable volume (MTV; lower limit of normal 80 mL, upper limit of normal 320 mL). Subjects were stratified as having rectal hyposensitivity (RH) when 1 or more sensory thresholds were greater than normal, or for rectal hypersensitivity when MTV was lower 80 mL. All subjects in between were defined as having normal rectal sensation. 
3.	Endoanal ultrasound two transducer, one sagittal and one axial). The internal and external anal sphincters were categorized as intact or abnormal by two independent reviewers. 
4.	Evacuation proctography. A standard mixture of porridge oats, water, and barium, with similar consistency to soft stool, was instilled using a calibrated large syringe into the unprepared rectum to a maximum of 180 mls. Patient was then transferred to a commode and defaecation assessed under fluoroscopy. Complete defaecation was defined as ≥ 90% of instilled past expelled, subjects repeated the evacuation attempts three times if unable to empty at first attempt with additional manoeuvres, like vaginal splinting for women. Grading of intussusception has been reported according to Oxford internal rectal prolapse grading system. Low grade are grade I (descent to proximal limit of rectocoele) and grade II, descends into the level of rectocoele (but not onto the anal canal).  High grade of intussusception are grade III (descents onto anal canal), grade IV (descents into anal canal). External rectal prolapse is grade V, with prolapse protrudes from the anus. Rectocoele has been defined as an outpouching of the rectal wall on defaecation and measurements have been calculated as the distance between the maximal anterior out bulge and the extrapolated line of the anterior rectal wall.

During the study period, 545 patients were referred to our third referral centre with the main symptoms of ODS, 471 females (86.4%) and 74 males (13.6%). Based on results from last appointment, patients have been classified into two groups “improvement” and “no improvement”. Several predicting factors have been analysed to understand if we can stratify patients during their initial assessment. 
Among demographic data, only age have reach statistical significance to predict improvement (median age is 51.6 in improvement group and 48.5 in the non-improvement, p=0.019). On the contrary, sex, previous proctological or pelvic floor surgery, hysterectomy, vaginal deliveries haven’t been reach statistical significance as predictors. 
Regards questionnaires, we have divided ICIQ-B in Bowel pattern symptoms (BPS), Bowel continence symptoms (BCS) and Quality of life (QoL) and we have found that patients with baseline worse QoL has worse outcomes (13.41 improvement vs 15.07 no improvement, p=0.012). Initial ODS score hasn’t results significant (9.7 improvement vs 9.8 no improvement, p=0.75) as well as Bristol stool chart (2.7 improvement vs 2.5 no improvement, p=0.2). 
In terms of pelvic floor tests, 403 (74.9%) had endoanal ultrasound and anorectal manometry, while 385 (70.6%) had defaecating proctography. None of the results from tests have resulted to be significant in predicting patients’ outcomes (results reported in table 1 and 2).
Regards interventions, 485 (89%) patient had conservative treatment, with a median number of sessions of 4.28 (range between 0-16) and a length of follow-up of 14.4 months (range 0-67.7), while 51 (9.4%) had surgery when conservative measures failed to achieve patients’ satisfactory improvements.  Conservative measures include counselling and correct toilet position training, information leaflets, pelvic floor exercises, prokinetics (19.8%), laxatives (37.1%), medications to increase the stools consistency (6.2%), use of suppositories (71.7%) and selective us of low and high volume irrigation (41.8%). None of them has been result a predictors of success for conservative treatment. Surgical interventions were offered to 51 (9.4%) in total, (11.5% in the improvement group and 5.3% in the no improvement group, p=0.02). Length of follow-up has been 14.8 months (16.6 in the improvement and 14.5 in the no improvement group, p=0.002).

Initial assessment for patients with ODS is important to direct them to conservative treatment only or a combination of conservative and surgical repair for those having associated anatomical abnormalities.  Predictors of success are important to avoid unnecessary interventions to patients and to use the available resources patients with specific symptoms. 
Despite our extensive statistical analysis, we have found that only advanced age (51.6 vs 48.5, p=0.019) and less compromised QoL in the ICIQ-B (13.41 vs 15.07, p=0.012) are predictors of success for improvement. Results obtained from tests as well as the presence or the absence of anatomical abnormalities or abnormal physiology haven’t been found to get any prognostic value in our cohort. Based on these findings and the fact that pelvic floor tests are invasive and expensive procedures, we should reserve them for patients not improving first line treatment.

Pelvic floor tests are not predictive of success for treatment of obstructive defaecation syndrome, which should be treated with a combination of conservative measures as first line. Tests should be reserved to patients who has failed first line treatment in the view to offer surgery, if anatomical abnormalities are present. Predictors of success should be identify to predict outcomes for patients with difficult defaecation.

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