External and internal rectal prolapse with their affiliated rectocele and enterocele, are associated with debilitating symptoms such as obstructed defecation, pelvic pain and faecal incontinence. Since perineal procedures are associated with a higher recurrence rate, an abdominal approach is commonly preferred. Despite the description of greater than three hundred different procedures, thus far no clear superiority of one surgical technique has been demonstrated. Ventral mesh rectopexy (VMR) is a relatively new and promising technique to correct rectal prolapse. In contrast to the abdominal procedures of past decades, VMR avoids posterolateral rectal mobilisation and thereby minimizes the risk of postoperative constipation. Because of a perceived acceptable recurrence rate, good functional results and low mesh-related morbidity in the short to medium term, VMR has been popularized in the past decade. Laparoscopic or robotic-assisted VMR is now being progressively performed internationally and several articles and guidelines propose the procedure as the treatment of choice for rectal prolapse. In this article, an outline of the current status of laparoscopic and robotic ventral mesh rectopexy for the treatment of internal and external rectal prolapse is presented.

Prolapse of the posterior compartment of the pelvic floor, including rectal prolapse (RP) and its affiliated rectocele and enterocele, is associated with socially debilitating symptoms such as obstructed defecation, pelvic pain and faecal incontinence[1-3]. In the past decades, multiple surgical techniques have been described for RP. There is consensus that perineal procedures are associated with a higher recurrence rate and therefore, an abdominal approach, when possible, is preferred[4,5]. The majority of the abdominal procedures, however, include posterolateral mobilization of the rectum resulting in new-onset or worsening postoperative constipation[6].

In the search to reduce postoperative constipation, ventral mesh rectopexy (VMR) was developed[6]. In this procedure, the rectum is mobilized ventrally and attached to the sacral promontory with a mesh. By avoiding posterolateral rectal mobilization, autonomic nerves are spared and the risk of postoperative constipation is minimised. By lifting the middle compartment of the pelvic floor, correction of other frequently accompanying pelvic prolapses and celes is achieved.

Laparoscopic or robotic-assisted VMR is being progressively performed internationally and several articles and guidelines propose the procedure as the treatment of choice for RP[7-10]. This topic highlight summarises and assesses current evidence on laparoscopic and robotic ventral mesh rectopexy (LVMR/RVMR) for the treatment of internal and external rectal prolapse (IRP/ERP).

Studies presenting a homogeneous group of patients with rectal prolapse syndromes treated with VMR (laparoscopic or robotic) as described by D’Hoore et al[6], avoiding posterolateral mobilization and using a synthetic mesh were selected. Laparoscopic and robotic outcomes had to be displayed separately. Studies describing a heterogeneous group were excluded. Articles using a biological mesh are described separately.

Pelvic floor dysfunction is regularly characterised by multi-visceral pelvic organ prolapse[58]. With an ageing population, the prevalence of uni- and multi-visceral pelvic organ prolapse will increase[59-61]. A growing number of articles discuss a multidisciplinary approach for multi-compartment prolapse, but only two studies avoid posterolateral rectal mobilization[62,63]. The first report, describing an open recto-vagino-vesicopexy, presented an improvement with constipation in 77% (P = 0.001), faecal incontinence in 69% (P = 0.005) and urinary incontinence in 50% (P = 0.18) of all patients respectively after 12 mo[63]. Two (8%) patients developed new-onset urinary incontinence. Slawik et al[62], performing a laparoscopic sacro-colpo-rectopexy, described an improvement in 91% of patients with faecal incontinence and a reduction in median CCIS of 10 points after six months. Obstructed defecation resolved in 80% of patients, but 7% of these underwent an additional bowel resection. New-onset obstructed defecation occurred in 3.8%, and urinary incontinence in 2.5% of patients respectively. No patient developed a recurrence after a median follow-up of 54 mo. Thus far, no robotic studies describing a multi-compartmental approach with a limited anterior rectal dissection are published.

Concerns over synthetic mesh-related complications such as erosion, dyspareunia, fistulation and stricturing have led to the introduction of a more expensive biological equivalent. The biological mesh is characterised by degradation of the graft and regeneration of host tissue[64]. In theory, this degradation could decrease the chance of erosion and chronic infection. Conversely, the partial resolution of the material may lead to a higher recurrence rate. In 2013, a systematic review by Smart et al[19] was published comparing 11 studies (767 patients) receiving synthetic mesh with two studies (99 patients) using a biologic graft. An erosion rate of less than one percent, with no difference identified between synthetic and biological mesh (0.7% vs 0%, P = 1.0%) was described. There was no significant difference in other mesh-related complications or short-term recurrence (3.7% vs 4.0%, P = 0.78). The multicentre study of Evans et al[20] and two recent biological mesh studies[65,66] (4 and 20 mo follow-up) showed similar rates of mesh erosion. However, Franceschilli et al[66] reported a much higher percentage prolapse recurrence rate of 14% after a mean follow-up of 20 mo. Improvement with obstructed defecation was described from 82% to 92% with a mean gain of CCCS between 9 and 13 points (P = 0.02 - P < 0.0001)[65-68]. Reduction in faecal incontinence complaints occurred in 73% and 85% of patients with a mean gain in FISI score between four and 6 points (P = 0.01-P = 0.001)[65-68]. One report demonstrated a median gain in CCIS of approximately 10 points (P = 0.0002)[65-68]. Wahed et al[67] was the only study describing new-onset complaints (4.6% with constipation and 3.1% with faecal incontinence). Only one study comparing and matching biological and synthetic mesh for LVMR (29 vs 29) excists, demonstrating no significant difference in mesh-related complications, recurrence or functional outcome after a median follow-up of 15.4 mo[30]. Mehmood et al[69], comparing 34 LVMR with 17 RVMR patients using biological mesh, demonstrated a minor significant advantage in median CCIS gain for LVMR (10 vs 9.5, P = 0.02). Conversely, a non-significant benefit in favour of the robot was seen in a reduction of the FISI (32 vs 35, P = 0.3). Both the functional outcomes of the robotic and the laparoscopic cohort compared favourably to other studies describing LVMR for ERP (Table 2). No recurrences or mesh-related complications were seen in either cohort after 12 mo. There is a lack of high-level comparative evidence with long-term follow-up for biological mesh, which demonstrates any significant difference in graft-related morbidity and recurrence rates. When more data becomes available, the choice of the mesh may be influenced by cost or possible comorbidity. In a recent publication a panel of experts suggested that biological grafts may be a better option in the following circumstances: young patients, women of reproductive age, diabetics, smokers, patients with a history of previous pelvic radiation or sepsis, inflammatory bowel disease, and in cases of intraoperative breach of the rectum or vagina[9].

LVMR has become popularised in the past decade and is the preferred technique for treating rectal prolapse syndromes by many surgeons, especially in Europe. The procedure is becoming increasingly applied with robotic assistance. The robot enhances visualisation and manoeuvrability to improve complicated procedures in the deep pelvis, such as dissection and intracorporeal suturing[70]. Robotic surgery has proven to be more expensive in the short-term, but may lead to an overall reduction of costs due to enhanced ergonomics for the surgeon[11,71,72]. However, a long-term cost-effectiveness analysis of LVMR vs RVMR has not been performed.

The current evidence shows that LVMR and RVMR are safe procedures in terms of intraoperative, postoperative and mesh-related complications. Both LVMR and RVMR generate an acceptable recurrence rate and satisfactory improvement of functional outcome, with only one small laparoscopic cohort reporting an overall non-significant deterioration with obstructed defecation after surgery[54]. There may be a trend towards a better outcome for obstructed defecation following RVMR as compared with LVMR, but the level of evidence is low[16,38]. LVMR and RVMR show similar good results for improvement of faecal incontinence. Based on the currently available data, no superiority for either technique can be determined. As compared with other observational studies describing an abdominal approach to treat rectal prolapse syndromes, VMR shows similar recurrence rates and less constipation postoperatively[5,22,41]. Circumspection is required interpreting these results, however. Heterogeneity between the articles in patient selection and outcomes measured makes it difficult to draw conclusions from the current literature. In addition, follow-up has been relatively short and lacks a systematic approach for the majority of studies, especially the robotic series. Since pelvic floor dysfunction increases with age, long-term follow-up is required to assess functional outcome and recurrence. The true mesh erosion rate can only be obtained with adequately powered, long term studies incorporating a vaginal and anorectal examination for every patient. Thus far, only level 3 evidence exists with a paucity of RCT’s and case controlled trials. There are no results of comparative studies including VMR available. In a recent critical appraisal, Lundby and Laurberg expressed their concerns about the rapid implementation of LVMR for obstructed defecation syndrome based on the contemporary evidence[73]. High-level comparative evidence is necessary to overcome these doubts and to determine the value of VMR in the definitive treatment of rectal prolapse syndromes.

This review focusses solely on VMR, but more than three hundred different procedures to treat rectal prolapse syndromes have been described. Thus far, no technique has been shown to be superior. This was confirmed by an international survey in 2012, showing no uniformity of surgical procedure[74]. The survey demonstrated, inter alia, that more than 20% of the surgeons preferred stapled transanal resection of the rectum (STARR) for the treatment of IRP. Festen et al[75] suggested an IRP associated with fecal incontinence should be treated with LVR and an IRP in combination with obstructed defecation with STARR or LVR. At present, one Italian trial is comparing LVMR with STARR for obstructed defecation syndrome[76]. In addition, there are eight ongoing surgical trials, of which five are mentioned by the cochrane study of Tou et al[11]; two comparing LVMR with Delorme’s procedure for ERP[77,78], one investigating the outcomes of LVMR versus laparoscopic posterior rectopexy without mesh[79], one comparing laparoscopic resection rectopexy (RR) with laparoscopic fixation rectopexy[80], one assessing the difference between standard mesh rectopexy with ventral rectopexy[81], one studying the efficacy of LVMR for the treatment of chronic constipation[82] and two examining LVMR versus RVMR[16,83]. The trial by Mäkelä-Kaikkonen et al[16] has presented its short-term results, but long-term outcomes are awaited. The survey also shows VMR and RR are the two most common abdominal procedures for RP[74]. RR was developed to reverse the symptoms of rectal denervation inertia which is associated with traditional posterolateral rectal mobilization, but introduces the risks of a pelvic anastomosis. Three trials, comparing (predominantly open) abdominal rectopexy with and without sigmoid resection, described that RR was associated with less postoperative constipation but with a higher complication rate (P > 0.05)[11]. There is a need for a well-designed and adequately powered RCT comparing these two techniques laparoscopically or robotic-assisted. Lastly, high-quality evidence for the choice of a specific mesh type, either synthetic or biological, is required. The authors do acknowledge the slow recruitment and logistical difficulties of performing such trials, however.

Ventral mesh rectopexy (laparoscopic and robotic) appears a safe and effective procedure to correct different rectal prolapse syndromes with a low morbidity rate, acceptable long-term recurrence rates and a good functional outcome.