Parastomal hernia repair outcomes in relation to stoma site with diisocyanate cross-linked acellular porcine dermal collagen mesh

Nanotechnology approaches in abdominal wall reconstruction: A narrative review about scaffold and meshes

Repairing abdominal wall defects poses challenges for surgeons. Although mesh reinforcement is commonly used for primary repair, nanotechnology has emerged as a promising approach for developing innovative repair techniques. Most research in this area focuses on fabricating scaffolds designed specifically for abdominal wall repair, particularly in cases of hernia. These scaffolds are engineered to replicate the structure and function of the native extracellular matrix. This review aimed to summarize the existing studies on the application of nanotechnology in abdominal wall reconstruction following injury or repair.

Reinforced tissue matrix to strengthen the abdominal wall following reversal of temporary ostomies or to treat incisional hernias

BACKGROUND

Abdominal wall deficiencies or weakness are a common complication of temporary ostomies, and incisional hernias frequently develop after colostomy or ileostomy takedown. The use of synthetic meshes to reinforce the abdominal wall has reduced hernia occurrence. Biologic meshes have also been used to enhance healing, particularly in contaminated conditions. Reinforced tissue matrices (RTMs), which include a biologic scaffold of native extracellular matrix and a synthetic component for added strength/durability, are designed to take advantage of aspects of both synthetic and biologic materials. To date, RTMs have not been reported to reinforce the abdominal wall following stoma reversal.

AIM

To evaluate the effectiveness of using an RTM to reinforce the abdominal wall at stoma takedown sites.

METHODS

Twenty-eight patients were selected with a parastomal and/or incisional hernia who had received a temporary ileostomy or colostomy for fecal diversion after rectal cancer treatment or trauma. Following hernia repair and proximal stoma closure, RTM (OviTex® 1S permanent or OviTex® LPR) was placed to reinforce the abdominal wall using a laparoscopic, robotic, or open surgical approach. Post-operative follow-up was performed at 1 month and 1 year. Hernia recurrence was determined by physical examination and, when necessary, via computed tomography scan. Secondary endpoints included length of hospital stay, time to return to work, and hospital readmissions. Evaluated complications of the wound/repair site included presence of surgical site infection, seroma, hematoma, wound dehiscence, or fistula formation.

RESULTS

The observational study cohort included 16 male and 12 female patients with average age of 58.5 years ± 16.3 years and average body mass index of 26.2 kg/m2 ± 4.1 kg/m2. Patients presented with a parastomal hernia (75.0%), incisional hernia (14.3%), or combined parastomal/incisional hernia (10.7%). Using a laparoscopic (53.6%), robotic (35.7%), or open (10.7%) technique, RTMs (OviTex® LPR: 82.1%, OviTex® 1S: 17.9%) were placed using sublay (82.1%) or intraperitoneal onlay (IPOM; 17.9%) mesh positioning. At 1-month and 1-year follow-ups, there were no hernia recurrences (0%). Average hospital stays were 2.1 d ± 1.2 d and return to work occurred at 8.3 post-operative days ± 3.0 post-operative days. Three patients (10.7%) were readmitted before the 1-month follow up due to mesh infection and/or gastrointestinal issues. Fistula and mesh infection were observed in two patients each (7.1%), leading to partial mesh removal in one patient (3.6%). There were no complications between 1 month and 1 year (0%).

CONCLUSION

RTMs were used successfully to treat parastomal and incisional hernias at ileostomy reversal, with no hernia recurrences and favorable outcomes after 1-month and 1-year.

Recent advances in skin collagen: functionality and non-medical applications

Abstract

During nature evolution process, living organisms have gradually adapted to the environment and been adept in synthesizing high performance structural materials at mild conditions by using fairly simple building elements. The skin, as the largest organ of animals, is such a representative example. Conferred by its intricate organization where collagen fibers are arranged in a randomly interwoven network, skin collagen (SC), defined as a biomass derived from skin by removing non-collagen components displays remarkable performance with combinations of mechanical properties, chemical-reactivity and biocompatibility, which far surpasses those of synthetic materials. At present, the application of SC in medical field has been largely studied, and there have been many reviews summarizing these efforts. However, the generalized view on the aspects of SC as smart materials in non-medical fields is still lacking, although SC has shown great potential in terms of its intrinsic properties and functionality. Hence, this review will provide a comprehensive summary that integrated the recent advances in SC, including its preparation method, structure, reactivity, and functionality, as well as applications, particularly in the promising area of smart materials.

Graphical abstract

Parastomal hernia repair with onlay mesh remains a safe and effective approach

Background

Parastomal hernia (PSH) management poses difficulties due to significant rates of recurrence and morbidity after repair. This study aims to describe a practical approach for PSH, particularly with onlay mesh repair using a lateral peristomal incision.

Methods

This is a retrospective review of consecutive patients who underwent PSH repair between 2001 and 2018.

Results

Seventy-six consecutive PSH with a mean follow-up of 93.1 months were reviewed. Repair was carried out for end colostomy (40%), end ileostomy (25%), ileal conduit (21%), loop colostomy (6.5%) end-loop colostomy (5%) and loop ileostomy (2.5%). The repair was performed either with a lateral peristomal incision (59%) or a midline incision (41%). Polypropylene mesh (86%), biologic mesh (8%) and composite mesh (6%) were used. Stoma relocation was done in 9 patients (12%). Eight patients (11%) developed postoperative wound complications. Recurrence occurred in 16 patients (21%) with a mean time to recurrence at 29.4 months. No significant difference in wound complication and recurrence was observed based on the type of stoma, incision used, type of mesh used, and whether or not the stoma was repaired on the same site or relocated.

Conclusion

Onlay mesh repair of PSH remains a practical and safe approach and could be an advantageous technique for high-risk patients. It can be performed using a lateral peristomal incision with low morbidity and an acceptable recurrence rate. However, for patients with significant adhesions and very large PSH, a midline approach with stoma relocation may also be considered.

Bioprinting of Collagen: Considerations, Potentials, and Applications

Collagen is the most abundant extracellular matrix protein that is widely used in tissue engineering (TE). There is little research done on printing pure collagen. To understand the bottlenecks in printing pure collagen, it is imperative to understand collagen from a bottom-up approach. Here it is aimed to provide a comprehensive overview of collagen printing, where collagen assembly in vivo and the various sources of collagen available for TE application are first understood. Next, the current printing technologies and strategy for printing collagen-based materials are highlighted. Considerations and key challenges faced in collagen printing are identified. Finally, the key research areas that would enhance the functionality of printed collagen are presented.

Radiological progression of end colostomy trephine diameter and area

Background

Development of a parastomal hernia is common following abdominoperineal excision (APE). The true incidence is difficult to assess fully owing to differing lengths of follow‐up and techniques used to assess herniation; radiological or clinical. The primary aim of this study was to evaluate colostomy diameter by studying the rate of change of axial and sagittal trephine diameters, trephine area, and the ratio of the trephine over time. A secondary aim was to investigate variation in trephine area and variables affecting parasternal hernia over time.

Methods

Serial CT scans performed after APE from January 2006 to December 2014 were reviewed. Variables analysed included age, sex, trephine position relative to rectus abdominis muscle (RAM), type of incision for stoma creation, and axial and sagittal trephine diameters measured on follow‐up CT. A Bayesian hierarchical modelling framework was used to examine the relationship of trephine diameters, area and ratio over time.

Results

Of 112 patients undergoing APE, 103 were eligible for analysis; this included 91 colostomies (88·3 per cent) through the RAM and 12 (11·7 per cent) lateral to the RAM. Median age of the patients was 68 years. Sixty patients (58·3 per cent) had a circular and 43 (41·7 per cent) a cruciate incision for stoma creation. The sagittal trephine diameter increased by 0·22 (95 per cent credible interval 0·12 to 0·32) mm/month for both sexes. Women reported a significant increase in axial trephine diameters; the male : female ratio difference was −0·17 (−0·30 to −0·03) mm/month and for trephine areas −6·21 (0·96 to 13·7) mm²/month. Patient age, colostomy trephine location and shape of incision were not statistically significant variables for parasternal hernia.

Conclusion

Female sex was the only variable affecting the rate of increase in axial trephine diameter and trephine area over time.

Prosthetic mesh placement for the prevention of parastomal herniation

BACKGROUND

Parastomal herniation is a common problem following formation of a stoma after both elective and emergency abdominal surgery. Symptomatic hernias give rise to a significant amount of patient morbidity, and in some cases mortality, and therefore may necessitate surgical treatment to repair the hernial defect and/or re-site the stoma. In an effort to reduce this complication, recent research has focused on the application of a synthetic or biological mesh, inserted during stoma formation to help strengthen the abdominal wall.

OBJECTIVES

The primary objective was to evaluate whether mesh reinforcement during stoma formation reduces the incidence of parastomal herniation. Secondary objectives included the safety or potential harms or both of mesh placement in terms of stoma-related infections, mesh-related infections, patient-reported symptoms/postoperative quality of life, and re-hospitalisation/ambulatory visits.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library 2018, Issue 1), Ovid MEDLINE (1970 to 11 January 2018), Ovid Embase (1974 to 11 January 2018), and Science Citation Index Expanded (1970 to 11 January 2018). To identify ongoing studies, we also searched the metaRegister of Controlled Trials (mRCT) on 11 January 2018.

SELECTION CRITERIA

We considered for inclusion all randomised controlled trials (RCTs) of prosthetic mesh (including biological/composite mesh) placement versus a control group (no mesh) for the prevention of parastomal hernia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the studies identified by the literature search for potential eligibility. We obtained the full articles for all studies that potentially met the inclusion criteria and included all those that met the criteria. Any differences in opinion between review authors were resolved by consensus. We pooled study data into a meta-analysis. We assessed heterogeneity by calculation of I2 and expressed results for each variable as a risk ratio (RR) with corresponding 95% confidence intervals (CI). We expressed continous outcomes as mean difference (MD) with corresponding 95% CIs.

MAIN RESULTS

We included 10 RCTs involving a total of 844 participants. The primary outcome was overall incidence of parastomal herniation. Secondary outcomes were rate of reoperation at 12 months, operative time, postoperative length of hospital stay, stoma-related infections, mesh-related infections, quality of life, and rehospitalisation rate. We judged the risk of bias across all domains to be low in six trials. We judged four trials to have an overall high risk of bias.The overall incidence of parastomal hernia was less in participants receiving a prophylactic mesh compared to those who had a standard ostomy formation (RR 0.53, 95% CI 0.43 to 0.66; 10 studies, 771 participants; I2 = 69%; low-quality evidence). In absolute numbers, the incidence of parastomal hernia was 22 per 100 participants (18 to 27) receiving prophylactic mesh compared to 41 per 100 participants having a standard ostomy formation.There were no differences in the need for reoperation (RR 0.90, 95% CI 0.50 to 1.64; 9 studies, 757 participants; I2 = 0%; low-quality evidence); operative time (MD -6.50 (min), 95% CI -18.24 to 5.24; 6 studies, 671 participants; low-quality evidence); postoperative length of hospital stay (MD -0.95 (days), 95% CI -2.03 to 0.70; 4 studies, 500 participants; moderate-quality evidence); or stoma-related infections (RR 0.89, 95% CI 0.32 to 2.50; 6 studies, 472 participants; I2 = 0%; low-quality evidence) between the two groups.We were unable to analyse mesh-related infections, quality of life, and rehospitalisation rate due to sparse data or because the outcome was not reported in the included studies.

AUTHORS' CONCLUSIONS

This Cochrane Review included 10 RCTs with a total of 844 participants. The review demonstrated a reduction in the incidence of parastomal hernia in people who had a prophylactic synthetic mesh placed at the time of the index operation compared to a standard ostomy formation. However, our confidence in this estimate is low due to the presence of a large degree of clinical heterogeneity, as well as high variability in follow-up duration and technique of parastomal herniation detection. We found the rate of stoma-related infection to be similar in both the intervention and control groups.

Parastomal hernia repair using the "top hat" technique - An initial experience in 30 patients at Memorial Sloan Kettering Cancer Center

Parastomal hernia repair remains a significant surgical challenge. Recurrence after standard "keyhole" or primary suture repair is common. We adopted and modified a new technique using a construct shaped like an inverted top hat. We review our experience over the last six years in the first 30 patients (31 consecutive procedures). Of these 31 procedures, six (19%) resulted in a parastomal hernia recurrence with a median follow-up of 31 months (range 0.5-80). Four of the recurrences occurred in our initial experience, when we constructed the top hat of xenograft alone. When the technique was modified, using a synthetic composite mesh for the underlay portion of the hat, there were only two subsequent recurrences in 16 patients (13%) with a median follow-up of 22 months. One of these "recurrences" was secondary to infection of the top hat construct, which had to be removed. This initial success in preventing recurrence of parastomal hernia is probably due to the design of the construct, for it occludes the vulnerable stoma/fascial angle, through which most parastomal hernia recurrences occur.

Synthetic vs biologic mesh for the repair and prevention of parastomal hernia

AIM

To outline current evidence regarding prevention and treatment of parastomal hernia and to compare use of synthetic and biologic mesh.

METHODS

Relevant databases were searched for studies reporting hernia recurrence, wound and mesh infection, other complications, surgical techniques and mortality. Weighted pooled proportions (95%CI) were calculated using StatsDirect. Heterogeneity concerning outcome measures was determined using Cochran’s Q test and was quantified using I². Random and fixed effects models were used. Meta-analysis was performed with Review Manager software with the statistical significance set at P ≤ 0.05.

RESULTS

Forty-four studies were included: 5 reporting biologic mesh repairs; 21, synthetic mesh repairs; and 18, prophylactic mesh repairs. Most of the studies were retrospective cohorts of low to moderate quality. The hernia recurrence rate was higher after undergoing biologic compared to synthetic mesh repair (24.0% vs 15.1%, P = 0.01). No significant difference was found concerning wound and mesh infection (5.6% vs 2.8%; 0% vs 3.1%). Open and laparoscopic techniques were comparable regarding recurrences and infections. Prophylactic mesh placement reduced the occurrence of a parastomal hernia (OR = 0.20, P < 0.0006) without increasing wound infection [7.8% vs 8.2% (OR = 1.04, P = 0.91)] and without differences between the mesh types.

CONCLUSION

There is no superiority of biologic over synthetic mesh for parastomal hernia repair. Prophylactic mesh placement during the initial surgery significantly reduces parastomal hernia occurrence regardless of the mesh type.

Onlay parastomal hernia repair with cross-linked porcine dermal collagen biologic mesh: long-term results

PURPOSE

The optimal technique and mesh type for parastomal hernia repair have yet to be ascertained. Biologic meshes have been advocated in parastomal hernia repair due to purported resistance to infection in contaminated fields. The aim of this study was to evaluate the effectiveness of additionally cross-linked acellular porcine dermal collagen mesh (Permacol) for onlay parastomal hernia repair.

METHODS

A retrospective review of case notes, and abdominal CT scans when available, was performed for consecutive patients who had a parastomal hernia repaired between January 2007 and May 2010. All hernias were repaired with onlay placement of the biologic mesh. Hernias were classified according to the Moreno-Matias classification where CT scans were available.

RESULTS

Over a 34-month period, 30 consecutive patients, median age 74 years, 17 female, underwent parastomal hernia repair using onlay biologic mesh. There were 23 paracolostomy and seven paraileostomy hernias. The hernia was primary in 26 patients. Pre-operative CT scans were available in 18 patients (Moreno-Matias Type 1 = 1, Type 2 = 4, Type 3 = 13). There was one perioperative death, and 29 patients were available for follow-up, and median duration of follow-up (either CT or clinical) was 36 months (range 3-79). Twenty-six patients developed recurrence of the parastomal hernia (89.6%), and median time to recurrence was 10 months (range 3-72),with Moreno-Matias Type 1 = 0, Type 2 = 4, Type 3 = 14, unknown = 8. Fifteen out of 26 patients have had repairs of the recurrence using a variety of techniques. Of these, 10 patients have had further recurrence.

CONCLUSION

Onlay repair of parastomal hernia with cross-linked porcine dermal collagen biologic mesh reinforcement has poor long-term outcomes with unacceptably high recurrence rates and should not be performed.

Repair of complex parastomal hernias

Development of parastomal hernias (PH) is very common after stoma formation and carries a risk of subsequent bowel incarceration, obstruction and strangulation. The management of PH remains a challenge for the colorectal surgeon, and there are currently no standardized guidelines for the treatment of PH. Even more difficult is the management of complex parastomal hernias (CPH). We conducted a review of the literature to identify recent developments in the treatment of CPH, including analysis of the use of synthetic and biologic mesh prostheses, method of mesh placement and surgical approach.

Porcine dermis implants in soft-tissue reconstruction: current status

Soft-tissue reconstruction for a variety of surgical conditions, such as abdominal wall hernia or pelvic organ prolapse, remains a challenge. There are numerous meshes available that may be simply categorized as either synthetic or biologic. Within biologic meshes, porcine dermal meshes have come to dominate the market. This review examines the current evidence for their use and the limitations of knowledge. Although there is increasing evidence to support their safety, long-term follow-up studies that support their efficacy are lacking. Numerous clinical trials that remain ongoing may help elucidate their precise role in soft-tissue reconstruction.

Hernia emergencies

Hernia emergencies are commonly encountered by the acute care surgeon. Although the location and contents may vary, the basic principles are constant: address the life-threatening problem first, then perform the safest and most durable hernia repair possible. Mesh reinforcement provides the most durable long-term results. Underlay positioning is associated with the best outcomes. Components separation is a useful technique to achieve tension-free primary fascial reapproximation. The choice of mesh is dictated by the degree of contamination. Internal herniation is rare, and preoperative diagnosis remains difficult. In all hernia emergencies, morbidity is high, and postoperative wound complications should be anticipated.

Long-term outcomes (>5-year follow-up) with porcine acellular dermal matrix (Permacol) in incisional hernias at risk for infection

PURPOSE

We reviewed retrospectively all patients undergoing abdominal wall reconstruction using porcine acellular dermal matrix (PADM) from 2004 to 2008 with follow-up assessment in 2012. Technique, short-term (infection, seroma, wound dehiscence), and long-term (mesh infection, recurrence) complications, and hernia recurrences were evaluated by physician examination ≥5 years postoperatively.

RESULTS

56 patients at high risk for infection had elective operation; nine had non-elective operation for complications of prior incisional hernia/hernia repair. Operations were clean, clean-contaminated, contaminated, or grossly infected in 49, 32, 12, and 6%, respectively. Techniques of repair included 10 onlay (six reinforced primary closures, four bridging patches), 47 sublay (20 reinforced primary closures, 27 bridging patches), six inlay, and two sandwich (sublay and onlay). Early complications (≤30 days postoperatively) occurred in 19 of the 65 patients (29%), including two prosthetic dehiscences from fascial attachment, 13 wound infections, and 4 seromas. After a mean follow-up of ≥5 years in 59 of 65 patients, physician-reported incidences of infection requiring removal of mesh or hernia recurrence were 25 and 66%, respectively. Hernia recurrence occurred in 12 of 26 (46%) patients with a reinforced repair and 27 of 33 (82%) with patched repairs. Mesh infection occurred in 7 of 24 patients with sublay patch and in 4 of 19 sublay reinforcement. The greatest recurrence rate was in contaminated (71%) and grossly infected wounds (100%), while recurrence rate was 63% in clean and 63% in clean-contaminated wounds.

CONCLUSIONS

At ≥5 years of follow-up, use of PADM as a bioprosthesis in ventral hernia in high-risk patients is unreliable as a definitive repair in the majority of patients, but may provide satisfactory outcomes in some patients.

Outcome of Abdominal Wall Hernia Repair with Permacol™ Biologic Mesh

The use of biologic mesh in abdominal wall operations has gained popularity despite a paucity of outcome data. We aimed to review the experience of a large healthcare organization with Permacol™. A retrospective study was conducted of patients who underwent abdominal hernia repair with Permacol™ in 14 Southern California hospitals. One hundred ninety-five patients were analyzed over a 4-year period. Operations included ventral/incisional hernia repairs, ostomy closures, parastomal hernia repairs, and inguinal hernia repairs. In 50 per cent of the patients, Permacol™ was used to reinforce a primary fascial repair and in 50 per cent as a fascial bridge. The overall complication rate was 39.5 per cent. The complication rate was higher in patients with infected versus clean wounds, body mass index (BMI) 40 kg/m2 or greater versus BMI less than 40 kg/m2, in patients with prior mesh repair, and when mesh was used as a fascial bridge. With a mean follow-up of 2.1 years, morbid obesity was associated with a higher recurrence. To date this is the largest study on the use of Permacol™ in abdominal wall hernia repair. In our patient population undergoing heterogeneous operations with a majority of wounds as Class II or higher, use of Permacol™ did not eliminate wound morbidity or prevent recurrence, especially in morbidly obese patients.

Management and complications of stomas

Stomas are created for a wide range of indications such as temporary protection of a high-risk anastomosis, diversion of sepsis, or permanent relief of obstructed defecation or incontinence. Yet this seemingly benign procedure is associated with an overall complication rate of up to 70%. Therefore, surgeons caring for patients with gastrointestinal diseases must be proficient not only with stoma creation but also with managing postoperative stoma-related complications. This article reviews the common complications associated with ostomy creation and strategies for their management.

Biological meshes: a review of their use in abdominal wall hernia repairs

PURPOSE

Biological meshes are mostly used in infected fields within complex abdominal wall hernia repairs. There is no consensus, however, on the most appropriate material to be used in a given situation.

METHODS

A literature review of published articles reporting the utilization of biological meshes in ventral/incisional hernia repair was conducted. Data were analyzed to compare the recurrence rates obtained with biological meshes.

MAIN FINDINGS

Only a few prospective comparative studies were identified. Most publications relate to AlloDerm®, Permacol™ and Surgisis™ with data from other meshes insufficient to draw conclusions. AlloDerm has a 0-100% recurrence rate among studies. It compares poorly with Surgisis and results in an unfavorable outcome when used as a 'bridge prosthesis'. Permacol has consistent recurrence rates of 0-15%, whatever the patients' profiles or the context of infected fields, when considering the most relevant studies. The Surgisis results are more conflicting: the mesh exhibits low recurrence rates in clean fields, but in infected fields the recurrence rate is up to 39%.

CONCLUSION

Taken together, these studies suggest that the cross-linked mesh, Permacol has the lowest failure rate and the longest time to failure, particularly in contaminated or infected fields. However, this data should be confirmed by large prospective randomized studies.