Prevention and treatment of parastomal hernia: a position statement on behalf of the Association of Coloproctology of Great Britain and Ireland

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1 Position doi: /codi : a position statement on behalf of the Association of Coloproctology of Great Britain and Ireland 1 Received 26 February 2018; accepted 30 April 2018 Abstract Aim The Association of Coloproctology of Great Britain and Ireland (ACPGBI) Delphi process identified prevention and treatment of parastomal hernia (PSH) as the second highest priority non-cancer related colorectal pathology. This position statement aims to summarize the current evidence base. Methods Four broad themes were identified (prevention, diagnosis/classification, management and operative repair). Guidelines are based on evidence from an extensive literature review using organized searches on the PubMed, MEDLINE, Embase and Cochrane databases. The Grading of s Assessment, Development and Evaluation (GRADE) system was adhered to for classifying the quality of evidence and reporting the strength of recommendations. Results The suture repair of PSH other than for patients in extremis is not recommended. Synthetic non-absorbable mesh can be used safely in the short term in the construction of colostomies post rectal surgery, but longer-term follow-up is needed. Other broad recommendations are made around access to stoma care nurses, prevention classification and management. Conclusion There is a lack of high quality evidence for many domains in the prevention and treatment of PSH but the results of several studies are awaited. What does this paper add to the literature? Parastomal hernias are a common and debilitating condition following stoma formation. This position statement from ACPGBI details the current evidence base and ongoing research for the prevention, diagnosis and management of parastomal hernias. Introduction Position statements of the Association of Coloproctology of Great Britain and Ireland (ACPGBI) are intended to act as a clinical guide for ACPGBI members and to facilitate evidence based decisions. The topics are intended to reflect the research priorities highlighted by the membership of the Association and are influenced by clinical need. The recent ACPGBI Delphi exercise identified the prevention and treatment of parastomal hernia (PSH) as the second most important non-cancer related question [1] (Fig. 1). There are people Correspondence to: Associate Professor Neil Smart, Exeter Surgical Health Services Research Unit, Royal Devon & Exeter Hospital, Barrack Road, Exeter, Devon, EX2 4DW, UK. drneilsmart@hotmail.com 1 Collaborating members are shown in the Appendix S1, in Supporting information. with stomas in the UK, with new ostomates each year [2]. The reported incidence of PSH varies widely in series from 5% to 50% as there is heterogeneity in the definition and mode of diagnosis, i.e. selfreported, clinical examination and radiological [3,4]. PSHs are symptomatic in 75% of patients, and can lead to reduced quality of life or to emergency presentations with strangulation and obstruction [5 7]. The cost of stoma appliances was estimated at 228 million in 2012 and these costs are increasing. Patients with stoma complications have even higher costs and this does not take into account the expense of stoma care nurses, readmissions and reoperations. Despite the high volume of patients undergoing stoma formation, there is a lack of high quality evidence for the prevention and ultimate management of PSHs. These guidelines outline the current evidence base for the prevention and management of PSH and identify ongoing research in this area. Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2),

2 Method The approach adopted in the formulation of this position statement mirrored that of previous ACPGBI position statements with a standardized approach of: 1 formulating the clinical questions; 2 searching for relevant evidence; 3 grading the evidence; 4 making relevant statements and/or recommendations. The guidelines are sub-divided into the major headings of prevention, diagnosis/classification, management and operative repair. As there are multiple systematic reviews and meta-analyses in the literature regarding management of PSHs they were not repeated to formulate this position statement. These guidelines are based on evidence from an extensive literature review using organized searches on the PubMed, MEDLINE, Embase and Cochrane databases. FM and NS performed the initial searches. Full articles were obtained; pairs of the included authors were allocated specific questions and assessed the literature to inform this position statement. All included authors reviewed the position statement to reach consensus. Articles were limited to English language. Additional resources were retrieved from references from retrieved articles and conference abstracts. See Appendix S1 for more detail on these methods. In keeping with the National Health Service, the Scottish Intercollegiate Guidelines Network and numerous other organizations we will adhere to the Grading of s Assessment, Development and Evaluation (GRADE) system of classifying the quality of evidence and reporting the strength of recommendations [8] (Fig. 2). Results Prevention Is there a role for stoma care nurses in the prevention of PSH? The Association of Stoma Care Nurses guidelines highlight the important areas in which stoma care nurses (SCNs) are integral for the patient journey when initially consenting for stomas, stoma marking, stoma appliance management and ongoing care [9]. There is some low quality evidence that preoperative stoma marking is beneficial in terms of quality of life and it is intuitive that a well-sited stoma is better for stoma appliance placement and avoiding a pannus in an obese patient [10]. There is a paucity of high quality evidence relating to the prevention of PSH specifically, with studies limited to observational cohorts only [11,12]. There is some evidence that patients are less physically active after primary stoma formation [13]. It is intuitive, however, that maintaining abdominal core musculature is beneficial for abdominal wall function and simple exercise programmes are available that facilitate patient engagement and concordance [9,11 13]. Most patients gain confidence from the use of support garments but they are not proven to stop the formation of PSHs with only observational studies to support their use in ostomates. Of note, a study of abdominal binders following epigastric or ventral hernia repairs demonstrated a subjective benefit but no significant difference in any other outcomes [14]. SCNs are essential for the psychological well-being of patients who are being considered for their first stoma and maintain a continuity of care following surgical intervention. They also act as a conduit for referrals to surgeons when patients have deteriorating symptoms and quality of life from parastomal complications and hernia [9]. SCNs are important for the overall well-being of all patients with a stoma. There is insufficient evidence to comment conclusively on whether SCN advice on exercise and support garments reduces the risk of PSH development. There is no evidence to suggest that SCN advice regarding exercise causes harm. SCNs should be involved in the perioperative counselling of patients with a stoma and offer lifestyle advice regarding support garments and exercise. Weak During primary stoma formation are there technical steps that may reduce the risk of PSH development? A number of technical steps during index stoma formation have been claimed to be important in predisposing to PSH formation. These include extraperitoneal placement of the afferent stoma limb, location of the stoma aperture [within or without the rectus fascia and, if within, lateral rectus abdominis positioned stoma (LRAPS) vs transrectus], shape of aperture (cruciate vs circle) and size of aperture. Transperitoneal vs extraperitoneal approach. Ameta-analysis by Kroese et al. [15] compared the extraperitoneal and transperitoneal route of stoma placement; it 6 Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2), 5 19

3 Figure 1 Highest priority non-cancer-related questions in the field of coloproctology. Figure 2 Grading of s Assessment, Development and Evaluation (GRADE) system of classifying the quality of evidence and reporting the strength of recommendations [2]. demonstrated that the extraperitoneal route was associated with lower rates of PSH, relative risk 0.36 (95% CI: ). However, these data are from a series comprising a mixture of retrospective non-randomized studies, some from the 1970s, and two randomized controlled trials (RCTs) with small numbers. Furthermore, randomized and non-randomized studies were combined within the same meta-analysis, which is not advocated by Cochrane [16]. The stoma may pass through the abdominal wall musculature either within the rectus sheath or lateral to the rectus sheath passing through the oblique muscles. Stomas that pass through the rectus sheath may either split the muscle or pass lateral to the rectus muscle (LRAPS). Within vs without the rectus sheath. The position of the stoma in relation to the rectus sheath has been purported to be important in terms of risk of development of PSH and was originally noted by Sj odahl et al. [17]. Subsequent studies that investigated this aspect of stoma creation failed to confirm the association of stoma position in relation to the rectus sheath with PSH formation; the systematic review by Carne et al. [3] failed to demonstrate any relationship with PSH formation. Similarly, a Cochrane review from 2013 also failed to demonstrate any association between stoma position in relation to the rectus sheath and PSH formation [18]. Within rectus sheath: LRAPS vs transrectal. The LRAPS was first described by Stephenson; this stoma trephine preserves the width of the rectus muscle and minimizes disruption of the layers of the abdominal wall. No PSH was demonstrated in a small series of 24 patients with a short-term median follow-up of 13 months (range 7 18 months) [19]. A feasibility RCT of 56 patients in the PATRASTOM trial found no difference in PSHs between the transrectal and LRAPS approach. However, this feasibility study assessed patients with shortterm defunctioning ileostomies and thus long-term data are not available. The larger PATRASTOM trial will recruit patients with end stomas and the results will better assess the differences between these approaches [20]. Aperture shape. Single institution case series from the 1980s onwards had advocated the use of circular staplers to create an accurately sized and shaped trephine in the anterior rectus sheath [21,22] in preference to the traditionally advocated cruciate incision [23]. However, although these series demonstrated low rates of PSH formation with medium- to long-term followup, methodological limitations and a lack of any comparison to alternative techniques promote a cautious interpretation of efficacy. Two ongoing studies, the Stoma-Const (NCT ) and the SMART trial (ISCRTN ), have circular creation of stoma trephines as one of the arms [24]. The SMART technique is an amalgamation of circular stapler with mesh prophylaxis [25]. The optimal shape of the trephine in the anterior abdominal wall remains the subject of debate. Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2),

4 Aperture size. The aperture size for stomas is not clearly defined in many studies, with most surgeons creating an aperture to admit two fingers or large enough to accommodate the bowel with associated mesentery. This has been approximately estimated at 3.5 cm [26] and others have advocated the use of circular staplers to create an accurately sized and shaped trephine [21]. Although there is currently no evidence to state what the optimal size or shape of the stomal aperture should be, patients with enlarging defects and those trephines greater than 2.5 cm are possibly at greater risk [27]. None of the studies has related the size of the trephine relative to the body habitus of the patient. It seems sensible to advocate the smallest possible trephine diameter that allows for passage of the afferent stomal limb and associated mesentery without causing ischaemia. 1 There is insufficient evidence to ascertain whether the extraperitoneal route of stoma construction reduces PSH rate in comparison to the transperitoneal route. 2 There is insufficient evidence to support the assertion of lower PSH rates with stoma trephines within the rectus sheath compared to those lateral to the rectus sheath. 3 There is insufficient evidence to advocate LRAPS in preference to a rectus abdominis muscle splitting stoma trephine. 4 There is currently insufficient evidence to support the use of any particular shape of incision (either circular or cruciate) in terms of reducing the rate of PSH. 5 There is insufficient evidence to support claims regarding the absolute optimal size of the stomal trephine; however, it is intuitive to use the smallest trephine without causing bowel ischaemia. None During primary stoma formation does the placement of a prophylactic mesh reduce the risk of PSH development? Twelve systematic reviews and meta-analyses have now been published regarding the use of prophylactic mesh during primary stoma creation [28 39]. All reviews have demonstrated a statistically significant risk reduction of PSH with the use of prophylactic mesh. The constituent RCTs are of variable quality and have improved in methodological rigour over time. The majority of studies to date have tended to focus on patients with a permanent end colostomy due to cancer in elective surgery (Table 1). Only one of the RCTs on mesh prophylaxis included emergency patients (5 out of 54) [40,41]. No data from RCTs specific to emergency surgery exist with only a single retrospective observational study addressing this group of patients. High quality RCTs that are multicentre and/or multinational with hundreds of patients included are either still recruiting or in follow-up (Stoma-Const NCT , SMART trial ISCRTN , PREVENT NTR2018, STOMA- MESH NCT ). The STOMAMESH trial recently published 1-year follow-up results demonstrating no difference in complications or PSH rate [42]. Primary end-point choice has focused on the presence or absence of PSH in a binary fashion with an incomplete exploration of the limitations of either clinical examination or CT imaging as diagnostic modalities. Ascertainment of the severity of PSH either in terms of the available classification systems or in terms of patient reported outcome measures or quality of life scales has only reached maturity with the most recently published trials. Some authors have highlighted a number of limitations of the methodological design of the RCTs included in some of the more recent systematic reviews [43] (Table 2). Some studies have been at moderate risk of bias with heterogeneity of included patients and followup techniques (telephone, clinical, radiological). However, this may in fact represent the dilemma at the heart of trial design between those that are explanatory and those that are pragmatic RCTs. Sample size calculations have not always been appropriately powered as attrition rates have been underestimated and because of competing risks of mortality due to a high proportion of cancer patients being unrecognized in the initial protocol. Furthermore, there are methodological issues with blinding and non-uniform assessment of complications in addition to the fact that many of the control arms thus far have lacked standardization, although this has been explicitly addressed in the Stoma-Const trial [24]. There is a lack of long-term follow-up; to date, only two RCTs have published follow-up data longer than 3 years [41,44], although more are in progress. There is a lack of head to head data comparing different types of mesh, and the site of mesh placement. The cost effectiveness of prophylactic mesh placement has been incompletely evaluated. The use of implants in hernia surgery has generally been associated with several potentially serious complications particularly in contaminated fields [45]. These complications included chronic infection and mesh erosion, sometimes necessitating further surgery to remove the mesh [46]. How these retrospective, database- 8 Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2), 5 19

5 derived reports of older synthetic mesh performance relate to modern macroporous synthetic meshes used in prophylaxis around stomas is unknown, although, of note, rates of mesh infection and erosion in RCTs have been extremely low. Biological meshes are reported to be more resistant to infection. A small study assessed the use of crosslinked porcine derived collagen meshes in stoma surgery and reported no PSHs in the mesh group albeit with only 10 in each arm of the study [47]. There are no head to head data comparing synthetic with biological meshes. There is one meta-analysis based on two studies that could not make any meaningful conclusions on biological meshes owing to small numbers [34]. Some retrospective studies from institutions that were early adopters of prophylactic mesh have failed to demonstrate an advantage in terms of PSH reduction when implemented in clinical practice [48,49]. Recent Danish registry data have highlighted high rates of paracolostomy bulging detected by SCNs on clinical examination even with prophylactic mesh placement [50]. The use of non-absorbable synthetic mesh may reduce the incidence of PSH in patients who have permanent end colostomy formation for cancer only during elective surgery. There is insufficient evidence regarding 1 optimal mesh position within the abdominal wall (retromuscular vs intraperitoneal on-lay mesh) 2 use of biologic meshes 3 prophylactic mesh in emergency surgery 4 prophylactic mesh use for ileostomy/urostomy 5 indications for stoma other than cancer (e.g. inflammatory bowel disease/functional) 6 cost effectiveness 7 long-term data, although this is in progress. Results are expected in the next few years. Prophylactic synthetic non-absorbable mesh may be used when constructing an elective permanent end colostomy for cancer only to reduce the risk of PSH development. Moderate Weak Diagnosis/classification What is the optimal method for diagnosing PSH? There are several options for diagnosing PSH which include clinical examination and imaging. Imaging Table 1 RCTs using mesh prophylaxis during stoma formation and those included during meta-analysis [41,42,44,47, ]. No mesh Mesh Emergency surgery Cancer IBD Benign Colostomy: ileostomy Mean BMI Sex M:F Mean age Emergency surgery Cancer IBD Benign N Colostomy: ileostomy Mean BMI Sex M:F Mean age N Study, first author Year : : : : Janes [40] Hammond [47] : :10 Elective : :10 Elective Serra-Aracil [100] : :0 Elective : :10 Elective Lopez-Cano [101] : :0 Elective : :0 Elective Fleshman [102] : :23 Elective : :19 Elective Tarcoveanu [103] n/a n/a n/a 22:0 Elective n/a n/a n/a 20:0 Elective Vierimaa [104] : :0 Elective : :0 Elective Lambrecht [44] : :0 Elective : :0 Elective Lopez-Cano [106] : :0 Elective : :0 Elective : :0 Elective : :0 Elective Brandsma [105] Odensten [42] : :0 Elective 106 n/a n/a : : n/a n/a Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2),

6 Table 2 Outcomes from parastomal hernia studies [41,42,44,47, ]. Outcome Study, first author Year Recurrence clinical Recurrence CT CT classification Complications Long term (> 3 years) mesh safety PSH repair Indications for repair Patient reported outcome measure Quality of life Janes [40] U U /U Hammond [47] 2008 U U Serra-Aracil [100] 2009 U U U (Moreno-Matias) U U Lopez-Cano [101] 2012 U U U Fleshman [102] 2014 U U U U (Stoma QOL) Tarcoveanu [103] 2014 U U U U U Vierimaa [104] 2015 U U U (EHS) U U U (VAS pain) Lambrecht [44] 2015 U U U (Moreno-Matias and EHS) U U Lopez-Cano [106] 2016 U U U (Moreno-Matias) U Brandsma [105] U U U (Moreno-Matias U U U U (Von Korff pain) U (SF-36 and EQ5D) and EHS) Odensten [42] 2017 U U U (Moreno-Matias and EHS) U U U 10 Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2), 5 19

7 modalities include CT or ultrasound and can be performed under different conditions, e.g. supine with the Valsalva manoeuvre or semi-prone. Clinical examination can be challenging as the findings are subjective such as bulging and cough impulse and it lacks the detail of the fascial defect, concomitant incisional hernias and other occult pathologies. In addition, clinical detection of PSH can be challenging in patients with obesity and the Chief Medical Officers report (2012) [51] estimates that 62% of the adult population are either overweight or obese. Prone CT scanning is more reliable than supine positioning for inter-observer variability between radiologists and radiologists vs surgeons but does involve exposure to radiation [52] (the sensitivity and specificity of prone CT is unknown) (Table 3). In abdominal wall hernias generally, the Valsalva manoeuvre has been demonstrated to improve the detection and characterization of hernias [53]. Data specific to PSH with Valsalva manoeuvre in the supine position are lacking. Some centres advocate the use of per-stomal three-dimensional (3D) ultrasonography which avoids radiation but will depend on the skill set of the ultrasonographer and the issues of inter-observer variability [54]. Clinical examination in combination with either 3D ultrasound or prone CT scanning are the most sensitive modalities for diagnosing PSH. Clinical examination in isolation may be sufficient in patients with normal body mass index. If there is any clinical doubt, either prone CT or 3D ultrasound in centres with the appropriate expertise are the investigations of choice for PSH. (Table 4). The EHS classification has not been validated and the Moreno-Matias is only used for colostomy associated PSHs diagnosed radiologically. The EHS classification is the most widely applicable grading system but is not validated; the Moreno- Matias is a radiological classification for colostomies only. Either the EHS or the Moreno-Matias classification can be used for the classification of PSHs. Management What is the optimal non-operative management of PSH? PSHs are common and the majority are managed conservatively by expert stoma care nursing. This is for several reasons: some are small, not diagnosed clinically and may be asymptomatic, patients with significant comorbidity, and patient choice. The Association of Stoma Care Nurses guidelines [9] describe the nonoperative management of PSHs, including advice on stoma appliances and adhesive adjuncts and the use of support garments. The safety and efficacy of non-operative management has not been subjected to high quality rigorous investigation. The rate of progression over time of the size and symptomatology of PSHs managed in this fashion is unknown. A recent multicentre retrospective cohort study of non-operative treatment confirmed that this strategy may be a better choice for patients with comorbidities or without significant symptoms [57] (Table 4). What is the optimal classification system to use when describing PSH The most commonly used classification systems for PSHs are the European Hernia Society (EHS) [55] and Moreno-Matias classifications [56]. The EHS classification has the benefit of being applicable to all stomas and can be used for intra-operative findings as well as radiological. It is classified based on the size of the PSH being less than or greater than 5 cm and if there is a concomitant incisional hernia with four grades (Table 4). The Moreno-Matias is graded 0, 1a, 1b, 2 and 3 and is a classification system for colostomies graded radiologically Table 3 Sensitivity and specificity of 3D ultrasound and CT scan. Modality Sensitivity Specificity 3D ultrasound 83% 100% CT scan (supine) 83% 50% CT prone Kappa value 0.8 for prone CT vs 0.63 for supine CT [50] For prone CT, the kappa values represent the level of agreement of surgeons and radiologists for the presence of PSH in patients imaged with both supine and prone CT [52,107]. Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2),

8 The optimal non-operative management of PSH requires a multidisciplinary approach. Patients need access to SCNs to advise on the best non-operative management options for PSHs. Strong What is the threshold for surgical treatment of PSH? Patients presenting as an emergency with non-resolving bowel obstruction and/or signs of intestinal ischaemia should be managed in an acute hospital, resuscitated and managed expeditiously by surgeons with appropriate expertise where available. This cohort of patients has high risks of postoperative morbidity, recurrence and mortality [58]. A study identified emergency surgery as the strongest risk factor for reoperation or death [59]. Elective management is more nuanced and is dependent on multiple factors including the patient s symptom profile and their comorbidity. There are limited data to prove that repairing a PSH electively actually improves stoma-specific patient reported outcomes or quality of life in comparison to expert SCN care. Overall symptom burden may decrease in the short term, but skin irritation and leak frequency may not be affected [60]. Of 131 patients referred for PSH repair, 61 underwent repair with a 10% recurrence rate at 2 years [60]. Symptoms decreased significantly in the immediate postoperative period and at 6 months. Although PSH repair is associated with high morbidity this is amplified in patients over 70 having emergency repair [58]. This must be considered when counselling patients regarding elective PSH repair in the over 70s group. What is not clear from any of the studies is what symptom burden and what level of impairment in quality of life makes the risks of PSH repair worth considering as a treatment option. Emergency indications for PSH surgery are nonresolving intestinal obstruction or signs of intestinal ischaemia. Elective repair indications will depend on the comorbidity of the patient and their symptoms with a risk benefit analysis. Emergency presentations of PSH should be managed by surgeons with appropriate expertise. Indications for elective repair will depend on the patient s symptom complex and risks for surgery. Further studies on patient reported outcome measures are needed. Strong What steps should be undertaken as part of patient optimization and preoperative planning? PSH repair requires a multidisciplinary and multi-modal approach to achieve excellent outcomes. Like other major surgery the best outcomes are achieved in patients who have undergone preoperative optimization of modifiable variables such as anaemia, smoking, body mass index (BMI) and exercise tolerance. Many of these variables have a well evidenced impact on surgical outcomes following colorectal and abdominal wall hernia surgery but may not have been studied in the context of PSHs specifically. It can therefore be inferred that correcting anaemia, smoking cessation, reducing BMI in obese patients and optimizing exercise tolerance will be beneficial to surgical outcomes. Risk calculators for ventral hernias have been developed to stratify the risk of complications following ventral hernia repairs, e.g. the Carolinas equation for determining associated risks (CeDar) [61]. This is an invaluable tool for highlighting Table 4 The European Hernia Society (EHS) and Moreno-Matias PSH classifications. EHS Moreno-Matias Grade Descriptor Grade Descriptor 1 Small PSH < 5 cm without IH 0 No formation of sac 2 Small PSH < 5 cm with IH 1a Bowel forming the colostomy with sac < 5cm 3 Large PSH > 5 cm without IH 1b Bowel forming the colostomy with sac > 5cm 4 Large PSH > 5 cm with IH 2 Sac containing omentum 3 Sac contains intestinal loop IH, incisional hernia. 12 Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2), 5 19

9 the current risks of morbidity and mortality for a patient but also how modifying adjustable variables such as weight or smoking status may reduce the risk. Correction of anaemia. Anaemia has been the subject of several studies and meta-analyses recently in the field of colorectal surgery looking at both the mode of iron administration and the outcomes from anaemia correction [62,63]. Perioperative anaemia is an independent risk factor for postoperative complications, longer hospital stays, infection and mortality [64,65]. Intravenous iron administration was more effective than oral with a median increase in haemoglobin concentration of 1.55 (interquartile range ) vs 0.5 ( 0.13 to 1.33) [66]. Smoking cessation. Smoking increases postoperative morbidity having an impact on both multiple organ systems and surgical complications [67]. Smoking is independently associated with PSH formation [68] and causes a four-fold increase in the formation of incisional hernias [69]. Smoking cessation greater than 4 8 weeks prior to surgery has been shown to reduce the impact on cellular function and complications [70,71]. Therefore, smoking should be stopped for at least 4 8 weeks prior to surgery. Obesity management. Obesity is now a major global epidemic; in the UK rates have doubled in the last 25 years with a prevalence of 24.8% amongst adults in 2012 [72]. The association with obesity and PSH is multi-factorial and it is argued that a high BMI causes stretching of the abdominal wall in addition to higher infection rates [73,74]. In ventral hernia repair complication and recurrence rates correlate with BMI. A BMI > 30 kg/m 2 is associated with significantly higher complication and recurrence rates, with preoperative weight loss being advised in those with class III (BMI > 35) and class IV (BMI > 40) obesity [75 80]. It is reasonable to extrapolate data from ventral hernia repair to PSH in the absence of parastomal-specific data [81]. Exercise. Evidence from the Improving Surgical Outcomes Group in 2005 reported an association between cardiopulmonary fitness and postoperative outcomes [82]. Patients with stomas are known to be less active after their index surgery and are at risk of being physically de-conditioned [13]. Tailored preoperative exercise programmes to improve cardiorespiratory fitness are available ( [83]. Cardiopulmonary exercise testing (CPET) may be used as the objective method of evaluating cardiorespiratory fitness and utilized as a surrogate for the stress of surgery. CPET has been demonstrated as useful for stratifying risk for abdominal surgery [84,85]. Imaging. The optimal imaging modality for PSH diagnosis is covered above (Diagnosis/classification). However, preoperative imaging for surgical planning of PSH repair is a separate consideration. Cross-sectional imaging (CT/MRI) is unrivalled in its ability to confirm the PSH, its size and sac content, the presence of concomitant hernias and exclusion of disease recurrence. In addition, it allows assessment of detailed abdominal wall anatomy to allow planning of the optimal surgical approach to hernia repair. Preoperative optimization of patients and preoperative planning are vitally important to improve outcomes. Correct preoperative anaemia (intravenous iron is more efficacious); advise patients to lose weight and aim for a BMI of < 35 kg/m 2 at least; smoking cessation and exercise programmes are recommended. Preoperative cross-sectional imaging is recommended to plan surgery and identify occult disease. Strong What steps should be undertaken to identify and mitigate risk and obtain informed consent? Identification of perioperative risk can be undertaken in the same manner as for other colorectal surgery including high-risk anaesthetic clinics, cardiopulmonary exercise testing and scoring systems [85,86]. Specific to PSH the CEDAR application and AHSQC Oracle ( may offer risks of complications and demonstrate to patients how optimization can reduce risk [61]. Data from these sources may inform discussions with patients about morbidity and mortality and stratifies patients into those who are likely to have a poor outcome from surgical management or those who may benefit from high dependency unit or intensive therapy unit support postoperatively in order to mitigate risk. The Montgomery ruling lays down the legal framework whereby the risks must be clearly and meaningfully discussed with patients [87]. All available management Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2),

10 options must be discussed with the patient so that they can make an informed decision about their preferred treatment. It highlights the importance of documenting discussions with patients and their families. Ideally consent should be completed before the day of surgery and patients can withdraw their consent at any time. A report was published on the higher risk surgical patient by the Royal College of Surgeons (England) and the Department of Health and recommendations were made about their management [88]. Further guidance from the General Medical Council (GMC) on consent is available [89]. Risk assessment and informed consent are of the utmost importance and also form part of the GMC framework for good medical practice. Consider risk stratification techniques (e.g. CPET) to assess risk and facilitate the consent conversation with patients and healthcare professionals. Strong Operative repair Is suture repair equivalent to mesh repair of PSH in the elective setting? In the elective setting there is strong evidence against using a suture repair in isolation for PSH [90]. A systematic review demonstrated an increased risk of PSH recurrence comparing suture with mesh repair (OR 8.9, 95% CI: , P < ), with recurrence rates of 70% in the suture repair group [91]. In the elective setting, a sutured repair is the simplest and least invasive method of all repairs for PSH and avoids laparotomy or laparoscopy. Surgeons need to be aware that some patients may still choose this method rather than more complicated strategies; they must advise the patient of the high recurrence rate, however. The focus for patients with an emergency presentation due to PSH is the preservation of life. The essential aspect of surgical technique is to manage the pathology in the timeliest fashion and temporise, avoiding complex mesh techniques. This suggests performing the minimal intervention necessary (e.g. a sutured repair) in order to extricate the patient from extremis without forming a complex surgical repair. The goal of repairing the hernia can be achieved formally with an elective procedure in the future. Suture repair consistently underperforms mesh repair with high recurrence rates and should preferably be only used in emergency situations. Suture repair should not be used for elective repair of PSHs unless appropriately counselled. High Strong Are laparoscopic and open surgical approaches equivalent? The laparoscopic approach for ventral hernias were first described in 1993 and since then a wide variety of techniques have been developed including laparoscopic PSH repair [92]. Despite wide adoption of the laparoscopic repair of ventral hernias and inguinal hernias, repairs for PSHs represent a smaller group. A Cochrane review of laparoscopic ventral hernias in 2011 identified no RCTs that studied PSHs [93]. Laparoscopic surgery for PSHs has the same relative contraindications such as patients with a hostile abdomen from multiple laparotomies or those that require more formal abdominal wall reconstruction/abdominoplasty. A meta-analysis assessed the data for the most commonly described laparoscopic techniques: Sugarbaker and keyhole and a combined Sugarbaker/ keyhole sandwich technique [91]. All these studies were retrospective case series with different prosthetic materials. Six studies of 110 patients undergoing the Sugarbaker technique showed a recurrence rate of 11.6% (95% CI: ). Seven studies investigating the keyhole technique performed in 160 patients demonstrated recurrence rates of 20.8% (95% CI: ). One study of 47 patients used a sandwich technique with a recurrence rate of 2.1% with a median follow-up of 20 months (6 48). Complication rates for the pooled data on laparoscopic surgery were low with rates of wound infection at 3.3%, mesh infection at 2.7%, other at 12.7%, with low mortality (1.2%). Laparoscopic surgery is safe but the evidence is based on small retrospective series with significant selection bias and almost no data regarding the type/classification or complexity of PSH/patient group repaired and therefore meaningful conclusions cannot be made. 14 Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2), 5 19

11 Laparoscopic surgery is safe and with the low quality evidence available has comparable outcomes with open surgery. None Very low None Is there an optimal position of mesh placement in the abdominal wall? The use of mesh is recommended in elective PSH repair; however, the literature comprises multiple papers of small single-centre retrospective series with heterogeneous outcome reporting, short follow-up, lack of standardized classification and no quality of life data [91]. The common approaches for open surgery include onlay, sub-lay and intraperitoneal (Sugarbaker/keyhole). Sub-lay and intraperitoneal on-lay mesh techniques have the mechanical advantage of intra-abdominal pressure holding the mesh in place. On-lay had the highest level of recurrence of 17.2% in a meta-analysis but the data were from small series and there are currently no RCT data on the site of mesh placement or type of prosthetic. Porcine derived collagen was used in an on-lay position in 30 patients with a high recurrence rate of 89.6% and the authors do not recommend the use of this material in an on-lay position for PSH [94]. The evidence for the site of mesh placement is of poor quality but there is a trend towards higher recurrence rates with on-lay placement. None Very low None Is there an optimal type of mesh for PSH repair? There is wide variation in the use of prosthetic materials in PSHs. The products available include non-absorbable synthetics [e.g. polyester, polypropylene, expanded polytetrafluoroethylene (eptfe)], absorbable synthetics and biological meshes. There is no head to head data on any of these meshes in PSHs and therefore no recommendation can be made on what type is superior for PSH repair [91]. PTFE is one of the most commonly used meshes but there are concerns regarding mesh shrinkage of up to 50% and the risk of erosion [95,96]. Composite meshes have the benefit of reducing the risk of adhesion formation to bowel with either rapidly absorbable or long-acting non-adhesive barriers but long-term data are lacking [96]. Biological meshes have equivalent rates of recurrence and complications in small series [97] and are favoured in patients with higher risk of contamination but these meshes are expensive and long-term and comparative data are lacking. Health economic analyses for different meshes used in this setting are lacking. On-lay biological meshes are not recommended for PSH repair due to the high recurrence from this retrospective series in 30 patients [94]. 1 There are multiple prosthetic implant options for PSH repair including absorbable synthetics, nonabsorbable synthetics and biological but currently no evidence to favour one type. Mesh repair is superior to suture repair but no mesh can be recommended over another until there is better evidence. Very low None 2 The recurrence rates for on-lay biological meshes for PSH repairs are unacceptably high. On-lay biological meshes are not recommended for PSH repairs. Strong Is stoma relocation associated with low rates of PSH recurrence? Relocation of the stoma is a described technique for managing PSH. It has the perceived benefit of moving the stoma to a new site making a new trephine through healthy fascia. However, this approach is associated with high recurrence rates. In a study comparing relocation vs the suture or mesh technique, relocation had the highest recurrence rate of 37.5% compared with 14.3% (suture) and 11.8% (mesh) [98]. In addition, by relocating the stoma there is a risk of further incisional herniation at the old stoma Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2),

12 site which has been quoted as 52% for stoma relocation [99]. Stoma relocation is associated with high rates of PSH development at the new stoma site and incisional hernia development at the site of previous incisions. Stoma relocation as a treatment for PSH is not recommended. Strong Conclusion PSHs are common and increase in incidence over time following surgery. The historical evidence base for the prevention and treatment of PSH is based on poor quality retrospective studies or RCTs with methodological issues. This is being addressed with higher quality studies currently recruiting or awaiting publication. Conflicts of interest The authors declare no conflict of interest. References 1 Tiernan J, Cook A, Geh I et al. Use of a modified Delphi approach to develop research priorities for the Association of Coloproctology of Great Britain and Ireland. Colorectal Dis 2014; 16: Black P. Stoma care nursing management: cost implications in community care. Br J Community Nurs 2009; 14: Carne PW, Robertson GM, Frizelle FA. Parastomal hernia. Br J Surg 2003; 90: Cheung MT, Chia NH, Chiu WY. Surgical treatment of parastomal hernia complicating sigmoid colostomies. Dis Colon Rectum 2001; 44: Ripoche J, Basurko C, Fabbro-Perray P, Prudhomme M. Parastomal hernia. A study of the French federation of ostomy patients. J Visc Surg 2011; 148: e Shabbir J, Britton DC. Stoma complications: a literature overview. Colorectal Dis 2010; 12: Nugent KP, Daniels P, Stewart B, Patankar R, Johnson CD. Quality of life in stoma patients. Dis Colon Rectum 1999; 42: Guyatt GH, Oxman AD, Vist GE et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ 2008; 336: Association of Stoma Care Nurses. ASCN Stoma Care National Clinical Guidelines. AoSCNU, nuk.com/wp-content/uploads/2016/03/ascn-clinical- Guidelines-Final-25-April-compressed pdf (accessed June 2018). 10 Maydick D. A descriptive study assessing quality of life for adults with a permanent ostomy and the influence of preoperative stoma site marking. Ostomy Wound Manage 2016; 62: North J. Early intervention, parastomal hernia and quality of life: a research study. Br J Nurs 2014; 23: S Thompson MJ. Parastomal hernia: incidence, prevention and treatment strategies. Br J Nurs 2008; 17: S Russell S. Physical activity and exercise after stoma surgery: overcoming the barriers. Br J Nurs 2017; 26: S Christoffersen MW, Olsen BH, Rosenberg J, Bisgaard T. Randomized clinical trial on the postoperative use of an abdominal binder after laparoscopic umbilical and epigastric hernia repair. Hernia 2015; 19: Kroese LF, de Smet GH, Jeekel J, Kleinrensink GJ, Lange JF. Systematic review and meta-analysis of extraperitoneal versus transperitoneal colostomy for preventing parastomal hernia. Dis Colon Rectum 2016; 59: Higgins JPT, Green S (eds). Cochrane Handbook for Systematic Reviews of Interventions. Chichester: John Wiley & Sons, Ltd, Sj odahl R, Anderberg B, Bolin T. Parastomal hernia in relation to site of the abdominal stoma. Br J Surg 1988; 75: Hardt J, Meerpohl JJ, Metzendorf MI, Kienle P, Post S, Herrle F. Lateral pararectal versus transrectal stoma placement for prevention of parastomal herniation. Cochrane Database Syst Rev 2013; CD Stephenson BM, Evans MD, Hilton J, McKain ES, Williams GL. Minimal anatomical disruption in stoma formation: the lateral rectus abdominis positioned stoma (LRAPS). Colorectal Dis 2010; 12: Hardt J, Seyfried S, Weiss C, Post S, Kienle P, Herrle F. A pilot single-centre randomized trial assessing the safety and efficacy of lateral pararectus abdominis compared with transrectus abdominis muscle stoma placement in patients with temporary loop ileostomies: the PATRASTOM trial. Colorectal Dis 2016; 18: O Resnick S. New method of bowel stoma formation. Am J Surg 1986; 152: Koltun L, Benyamin N, Sayfan J. Abdominal stoma fashioned by a used circular stapler. Dig Surg 2000; 17: Goligher JC. Extraperitoneal colostomy or ileostomy. Br J Surg 1958; 46: Correa Marinez A, Erestam S, Haglind E et al. Stoma- Const the technical aspects of stoma construction: study protocol for a randomised controlled trial. Trials 2014; 15: Williams NS, Nair R, Bhan C. Stapled mesh stoma reinforcement technique (SMART) a procedure to prevent 16 Colorectal Disease ª 2018 The Association of Coloproctology of Great Britain and Ireland. 20 (Suppl. 2), 5 19

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