Table 2 Definitions of secondary outcomes

Surgical complications

Postoperative ileus

Obstructive or paralytic symptoms after surgery with the need to suspend food intake and/or insert a gastric tube; this has to be confirmed radiologically (by abdominal sonography or plain abdominal X-ray or CT scan)

Postoperative hemorrhage

Need for administration of two or more red cell concentrates within the first 24 h postoperatively or need for reoperation

Surgical site infection

CDC definition[21]

Intra-abdominal abscess

Intra-abdominal collection of purulent or infected fluid (confirmed by culture) confirmed by puncture or by surgical reintervention

Anastomotic leakage

Grade A-C, Definition of grade according to International Study Group of Rectal Cancer 2010, diagnosed by CT scan with radiographic enema, endoscopy, drain secretion (stool) or reoperation

Non-surgical complications

Thrombosis

Clinical evidence (for example, pain, swelling, warmth, erythema) of a leg or pelvic vein thrombosis confirmed by duplex sonography or CT angiography, which was not previously known

Pulmonary embolism

Clinical (for example, tachycardia, dyspnea) and/or radiological evidence of pulmonary embolism confirmed by spiral CT or lung perfusion scintigram

Postoperative pulmonary infection

At least three of the following:

- temperature > 38°C

- purulent tracheal secretion

- leucocytes >12 or < 4.5 [10E9/L]

- elevated CRP

AND Evidence for pulmonary infection radiologically

Renal failure

Need for dialysis or hemofiltration

Cerebral insult

Ischemic or non-ischemic cerebrovascular event with persistent paresis or paralysis without previous history confirmed by CT or MRT

Myocardial infarction

Electrocardiogram (NSTEMI or STEMI) and enzyme (Troponin I) changes suggestive of myocardial infarction or needing admission to coronary care unit

Serious adverse events

SAE occurring from the day of randomization until regular end of trial follow-up or withdrawal

Mortality

All causes of mortality within 3 months after primary surgery

Duration of surgical intervention

First incision to the completion of skin closure (resection rectopexy) or the last coloanal suture (Delorme’s procedure)

Length of initial hospital stay

Means the hospitalization period from the primary operation date until the day of discharge (= postoperative hospital stay)

Reoperation rate for recurrent prolapse

Any surgical intervention for a recurrence

Cumulative hospital stay

Defined by the days in hospital after the primary surgery as well as the following hospitalizations due to complications or recurrence within 24 months after the primary operation

Change of quality of life, constipation and incontinence

Measured by means of the appropriate questionnaires SF-12, ([22], validated in German), Herold constipation score ([23], evaluated in German, but not yet published), Wexner-Score ([10], non-validated in German, most commonly used score) and Rockwood-FIQLScore ([24], validated), prior to the surgical intervention as well as 6, 12, and 24 months after the intervention