The objective of the study will be to evaluate the clinical and functional outcome of patients with obstructed defecation sndrome (ODS) associated to internal rectal prolapse, treated with transanal prolassectomy (STARR) surgery compared to those treated with laparoscopic ventral rectopexy (LVR).

This randomized controlled trial (single center, prospective, randomized controlled, parallel, and single-blind trial) is designed to compare the outcome of patients with ODS and rectal prolapse undergoing transanal prolapsectomy with mechanical stapler (STARR) versus laparoscopic ventral rectopexy (LVR), with the aim of evaluating the most appropriate surgical choice.

The study will be conducted at the Surgical Unit 2 of the University Hospital of Ferrara, Italy. Patients suffering from rectal prolapse and ODS that will refer to the colorectal and pelvic floor clinic of the University Hospital Ferrara, and eligible for surgery, will be evaluated consecutively after expressing consent to participate in the study by signing an informed consent.

The duration of the study for each patient will be expected to be 48 months with follow-up at 1, 3, 6, 12, 24, 36, and 48 months postoperatively.

Eligible patients will receive information about participating in the trial by their surgeon. Consecutive eligible patients will be randomly assigned to one of two groups with a 1:1 equal allocation ratio.

Patients eligible for the study will be randomized on a 1:1 basis to undergo transanal prolassectomy (Group 1: STARR) or laparoscopic ventral rectopexy with mesh placement (Group 2: LVR).

An independent individual will perform randomization using a software randomization program. Randomization will be performed by a randomized list. The assignment sequence will be generated from a random numerical series generated through a computerized list. Randomization will be in blocks of 4. Group assignments will be unknown to those responsible for data collection and those who will be responsible for statistical analysis and clinical evaluation of patients.

The diagnosis of ODS will be attributed after clinical evaluation at the colorectal clinic and on the basis of the presence of one or more symptoms associated with this disorder, such as to reach a score of 14 and above according to the validated score of ODS of Altomare.

Assessment After recruitment and consent, all patients under study will be asked and collected demographic and clinical information with comorbidities (in particular diabetes, fibromyalgia, depressive disorders, neurological diseases, COPD), parity, previous pelvic surgery, type of surgery, time of hospitalization and any complications (according to Clavien-Dindo classification).

Data concerning the grade of rectoanal prolapse, according with Oxford Classification [20], and rectocele grading will be collected through outpatient proctological evaluation associated with proctoscopy, rectal manometry, and Rx defecography. Colonoscopy will be also performed in every patient to exclude colorectal cancer.

The severity of the ODS will be scored with the Altomare's ODS scoring system. Constipation and fecal incontinence will be measured by obtaining their scores through the administration of validated questionnaires such as the Wexner Constipation score, and the Cleveland Clinic Fecal Incontinence Score (CCFI).

Quality of life will be also evaluated by the patient assessment of constipation quality-of-life (PAC-Qol) questionnaire. The study of eventually associated pelvic distress will be assessed by administering validated questionnaires such as the Pelvic Floor Distress Inventory (PFDI-score, short form) and the Pelvic Floor Impact Questionnaire (PFQI-score, short form).

The scores obtained, as well as the presence of symptoms (fecal incontinence, constipation, or ODS) will be calculated before and after surgery (at 6, 12, 24, 36, and 48 months). All patients will be followed up on an outpatient basis at 7 days, 1 month, 3 months, 6 months, 12 ,24, 36, and 48 months after surgery. Rectal manometry and defecography will be performed after 12 months after surgery.

Surgical intervention All the procedures will be performed by a single surgeon (SA). The LVR technique used for this protocol is as previously described. Subjects randomized to this arm will receive a standard LVR. Briefly, the peritoneum is opened over the right side of the sacral promontory. The mesorectum is dissected and extended in an inverted J-form along the right side. The rectovaginal septum is opened to the pelvic floor. Biologic mesh (Permacol) is sutured to the ventral aspect of the rectum with non-readsorbable stitches. The proximal end of the mesh is fixed on the anterior longitudinal ligament at sacral promontory with nonabsorbable tacks. The incised peritoneum is then closed to over the mesh.

Subjects randomized to STARR arm will undergo a STARR procedure. Briefly, a circular anal dilator is introduced into the rectum. The purse-string anoscope is used to complete the anterior hemi-circumference purse-string suture, about 2-3 cm above the haemorrhoidal apex. A 33-mm circular stapler (Ethicon, ppH01) is opened, inserted until crossing the purse-string which is then tied with a knot. Then the stapler is closed and fired. The same hemi-circumference purse-string suture is performed in the posterior rectal wall. A second application of the stapler on the posterior wall is inserted, closed and fired.

The duration of the study will be 2 years. The study will be conducted in accordance with the principles of Helsinki Declaration, with approval of the medical ethics review board of S. Anna University Hospital. A written informed consent will be obtained from all enrolled patients.

The report will comply with the strengthening the reporting of randomized studies (CONSORT).

Inclusion Criteria:

• female gender,
• the presence of rectorectal or rectoanal intussusception as main cause of ODS, confirmed by defecography,
• type of operation performed (STARR or LVR),
• ODS score > 14 [17]
• PACQoL >32 [18]
• ODS symptoms for at least 12 months prior to enrollment
• Failure of at least 6 months of medical therapy

Exclusion Criteria:

• male gender,
• severe fecal incontinence (CCS score>6, Maximum Resting Pressure at rectal manometry < 50 mmHg),
• combined procedures
• previous surgery on rectum or anus for cancer or rectal prolapse, inflammatory bowel disease, other type of surgery to relieve ODS
• pregnancy,
• anismus or dissinergic defecation
• full-thickness prolapse
• stress urinary incontinence associated
• histerocele or cystocele associated (since we usually correct both defects in the same surgical procedure)
• prior pelvic radiotherapy
• slow transit constipation defined as ≤ 2 bowel movements per week,
• any psychiatric diseases.