What is the evidence for the use of biologic or biosynthetic meshes in abdominal wall reconstruction?

INTRODUCTION: Although many surgeons have adopted the use of biologic and biosynthetic meshes in complex abdominal wall hernia repair, others have questioned the use of these products. Criticism is addressed in several review articles on the poor standard of studies reporting on the use of biologic meshes for different abdominal wall repairs. The aim of this consensus review is to conduct an evidence-based analysis of the efficacy of biologic and biosynthetic meshes in predefined clinical situations. METHODS: A European working group, "BioMesh Study Group", composed of invited surgeons with a special interest in surgical meshes, formulated key questions, and forwarded them for processing in subgroups. In January 2016, a workshop was held in Berlin where the findings were presented, discussed, and voted on for consensus. Findings were set out in writing by the subgroups followed by consensus being reached. For the review, 114 studies and background analyses were used. RESULTS: The cumulative data regarding biologic mesh under contaminated conditions do not support the claim that it is better than synthetic mesh. Biologic mesh use should be avoided when bridging is needed. In inguinal hernia repair biologic and biosynthetic meshes do not have a clear advantage over the synthetic meshes. For prevention of incisional or parastomal hernias, there is no evidence to support the use of biologic/biosynthetic meshes. In complex abdominal wall hernia repairs (incarcerated hernia, parastomal hernia, infected mesh, open abdomen, enterocutaneous fistula, and component separation technique), biologic and biosynthetic meshes do not provide a superior alternative to synthetic meshes. CONCLUSION: The routine use of biologic and biosynthetic meshes cannot be recommended.

European Hernia Society guidelines on prevention and treatment of parastomal hernias

Background International guidelines on the prevention and treatment of parastomal hernias are lacking. The European Hernia Society therefore implemented a Clinical Practice Guideline development project. Methods The guidelines development group consisted of general, hernia and colorectal surgeons, a biostatistician and a biologist, from 14 European countries. These guidelines conformed to the AGREE II standards and the GRADE methodology. The databases of MEDLINE, CINAHL, CENTRAL and the gray literature through OpenGrey were searched. Quality assessment was performed using Scottish Intercollegiate Guidelines Network checklists. The guidelines were presented at the 38th European Hernia Society Congress and each key question was evaluated in a consensus voting of congress participants. Results End colostomy is associated with a higher incidence of parastomal hernia, compared to other types of stomas. Clinical examination is necessary for the diagnosis of parastomal hernia, whereas computed tomography scan or ultrasonography may be performed in cases of diagnostic uncertainty. Currently available classifications are not validated; however, we suggest the use of the European Hernia Society classification for uniform research reporting. There is insufficient evidence on the policy of watchful waiting, the route and location of stoma construction, and the size of the aperture. The use of a prophylactic synthetic non-absorbable mesh upon construction of an end colostomy is strongly recommended. No such recommendation can be made for other types of stomas at present. It is strongly recommended to avoid performing a suture repair for elective parastomal hernia. So far, there is no sufficient comparative evidence on specific techniques, open or laparoscopic surgery and specific mesh types. However, a mesh without a hole is suggested in preference to a keyhole mesh when laparoscopic repair is performed. Conclusion An evidence-based approach to the diagnosis and management of parastomal hernias reveals the lack of evidence on several topics, which need to be addressed by multicenter trials. Parastomal hernia prevention using a prophylactic mesh for end colostomies reduces parastomal herniation. Clinical outcomes should be audited and adverse events must be reported.

Comparison of hernia registries: the CORE project.

INTRODUCTION: The aim of the international CORE project was to explore the databases of the existing hernia registries and compare them in content and outcome variables. METHODS: The CORE project was initiated with representatives from all established hernia registries (Danish Hernia Database, Swedish Hernia Registry, Herniamed, EuraHS, Club Hernie, EVEREG, AHSQC) in March 2015 in Berlin. The following categories were used to compare the registries: initiation and funding, data collection and use for certification of hernia centers, patient data and data protection, operative data, registration of complications and follow-up data. RESULTS: The Danish Hernia Database is the only one to qualify as a genuine national registry where participation is compulsory for entry of all procedures by all surgeons performing a hernia operation. All other registries have to be considered as voluntary and completeness of data depends upon the participating hospitals and surgeons. Only the Danish Hernia Database and the Swedish Hernia Registry are publicly funded. All other registries are reliant on financial support from the medical technology industry. As an incentive for voluntary participation in a hernia registry, hospitals or surgeons are issued a certificate confirming that they are taking part in a quality assurance study for hernia surgery. Due to data protection and privacy regulations, most registries are obliged or have chosen to enter their patient data anonymously or coded. The Danish Hernia Database and Swedish Hernia Registry utilize a national personal patient code. In the Herniamed Registry, patient data are saved in a coded and anonymous format after obtaining the patient's informed consent. CONCLUSION: Despite the differences in the way data are collected for each of the listed hernia registries, the data are indispensable in clinical research.

European Hernia Society guidelines on prevention and treatment of parastomal hernias.

BACKGROUND: International guidelines on the prevention and treatment of parastomal hernias are lacking. The European Hernia Society therefore implemented a Clinical Practice Guideline development project. METHODS: The guidelines development group consisted of general, hernia and colorectal surgeons, a biostatistician and a biologist, from 14 European countries. These guidelines conformed to the AGREE II standards and the GRADE methodology. The databases of MEDLINE, CINAHL, CENTRAL and the gray literature through OpenGrey were searched. Quality assessment was performed using Scottish Intercollegiate Guidelines Network checklists. The guidelines were presented at the 38th European Hernia Society Congress and each key question was evaluated in a consensus voting of congress participants. RESULTS: End colostomy is associated with a higher incidence of parastomal hernia, compared to other types of stomas. Clinical examination is necessary for the diagnosis of parastomal hernia, whereas computed tomography scan or ultrasonography may be performed in cases of diagnostic uncertainty. Currently available classifications are not validated; however, we suggest the use of the European Hernia Society classification for uniform research reporting. There is insufficient evidence on the policy of watchful waiting, the route and location of stoma construction, and the size of the aperture. The use of a prophylactic synthetic non-absorbable mesh upon construction of an end colostomy is strongly recommended. No such recommendation can be made for other types of stomas at present. It is strongly recommended to avoid performing a suture repair for elective parastomal hernia. So far, there is no sufficient comparative evidence on specific techniques, open or laparoscopic surgery and specific mesh types. However, a mesh without a hole is suggested in preference to a keyhole mesh when laparoscopic repair is performed. CONCLUSION: An evidence-based approach to the diagnosis and management of parastomal hernias reveals the lack of evidence on several topics, which need to be addressed by multicenter trials. Parastomal hernia prevention using a prophylactic mesh for end colostomies reduces parastomal herniation. Clinical outcomes should be audited and adverse events must be reported.

Prophylactic mesh to prevent parastomal hernia after end colostomy: a meta-analysis and trial sequential analysis.

PURPOSE: Prevention of parastomal hernia (PSH) formation is crucial, given the high prevalence and difficulties in the surgical repair of PSH. To investigate the effect of a preventive mesh in PSH formation after an end colostomy, we aimed to meta-analyze all relevant randomized controlled trials (RCTs). METHODS: We searched five databases. For each trial, we extracted risk ratios (RRs) of the effects of mesh or no mesh. The primary outcome was incidence of PSH with a minimum follow-up of 12 months with a clinical and/or computed tomography diagnosis. RRs were combined using the random-effect model (Mantel-Haenszel). To control the risk of type I error, we performed a trial sequential analysis (TSA). RESULTS: Seven RCTs with low risk of bias (451 patients) were included. Meta-analysis for primary outcome showed a significant reduction of the incidence of PSH using a mesh (RR 0.43, 95% CI 0.26-0.71; P = 0.0009). Regarding TSA calculation for the primary outcome, the accrued information size (451) was 187.1% of the estimated required information size (RIS) (241). Wound infection showed no statistical differences between groups (RR 0.77, 95% CI 0.39-1.54; P = 0.46). PSH repair rate showed a significant reduction in the mesh group (RR 0.28 (95% CI 0.10-0.78; P = 0.01). CONCLUSIONS: PSH prevention with mesh when creating an end colostomy reduces the incidence of PSH, the risk for subsequent PSH repair and does not increase wound infections. TSA shows that the RIS is reached for the primary outcome. Additional RCTs in the previous context are not needed.

Retrospective observational study on the incidence of incisional hernias after reversal of a temporary diverting ileostomy following rectal carcinoma resection with follow-up CT scans.

BACKGROUND: Wounds resulting from the closure of temporary stomas have a high risk of developing an incisional hernia (IH) with incidences around 30% in studies designed to investigate this outcome. A temporary diverting ileostomy (TDI) is often used in patients after low anterior resection (LAR) for rectal cancer. METHODS: The OSTRICH study is a retrospective cohort study of rectal cancer patients who had a LAR with a reversed TDI and at least one CT scan during follow-up. Two radiologists independently evaluated all abdominal CT scans to diagnose IH at the ileostomy wound and additionally, IH at the laparotomy site. RESULTS: From the oncological database of rectal cancer patients treated from 2003 till 2012 (n = 317) a cohort of 153 patients that fulfilled the inclusion criteria was identified. Rectal cancer resection was performed by laparoscopy in 53 patients (34.6%) and by laparotomy in 100 patients (65.4%). A total of 17 IH (11.1%) was diagnosed at the former stoma site after a mean follow-up of 2.6 years. Of these, 8 IH were in patients who had a laparoscopic LAR (15.1%) and 9 IH in patients who had an open LAR (9.0%) (Fisher's exact test; p = 0.28). IH on the other abdominal wall incisions was reported in 69 patients (45.1%). Of these, 10 patients underwent laparoscopic rectal surgery (18.9%) and in 59 patients had open rectal surgery (59.0%) (Fisher's exact test; p < 0.0001). CONCLUSION: We found a lower number of incisional hernias (11.1%) after reversal of ileostomies than expected from the literature. In contrast to the findings at the ileostomy site, a very high frequency of IH (59.0%) after LAR by laparotomy was found, which was significantly higher than after laparoscopic LAR.

Retrospective observational study on the incidence of incisional hernias after colorectal carcinoma resection with follow-up CT scan.

BACKGROUND: Incisional hernia (IH) is the most frequent complication after colorectal carcinoma (CRC) resection. The incidence depends on the method of follow-up, where ultrasound yields a significant number of additional hernias compared to clinical examination alone. Not many studies have evaluated the value of computed tomography (CT) to diagnose IH. METHODS: The CorreCT study is a retrospective cohort study of IH after CRC surgery by clinical examination and by CT, as reported in the medical files. Additional independent reviewing of all CTs by two radiologists was performed. RESULTS: From the oncological database (2004-2008) of the hospital, 598 patients with CRC were identified. The data of 448 consecutive patients who underwent surgery were analyzed. Tumors were resected by laparotomy in 366 patients (81.7 %), by laparoscopy in 76 patients (17.0 %) and by laparotomy after conversion in 6 patients (1.3 %). A clinical follow-up by the surgeon in 282 patients (62.9 %) with a mean duration of 33 months, yielded 49 patients with IH (17.4 %). The mean time of IH diagnosis (T1) was 19 months. Only 16 patients (33 %) underwent a hernia repair. For 363 patients (81.0 %), CT follow-up was available for a mean period of 30 months. In 84 patients (23.1 %), an IH was diagnosed with a mean T1 of 21 months. The review of all CTs by two independent radiologists yielded additional IH in 19 and 21 patients, respectively, increasing the IH rate to 29.1 and 29.7 %, respectively, and with a decrease in mean T1 to 14 months. The inter-observer agreement between the radiologists had a Kappa-statistic of 0.73 (95 % CI 0.65-0.81). For those patients with disagreement between the radiologists, a final agreement was made during an additional reviewing session of both radiologists, increasing the IH rate to 35.0 %. Comparing clinical follow-up, routine CT follow-up, and reassessed CT follow-up we found a statistically significant difference between the three methods of IH detection (p < 0.0001). CONCLUSION: CT follow-up can identify significantly more IH than clinical examination alone, in particular if the radiologist focuses on IH development. Furthermore, we showed that focused CT evaluation diagnosed IH 7 months earlier than routine CT and 5 months earlier than clinical follow-up alone.

Single centre observational study to evaluate the safety and efficacy of the Proceed™ Ventral Patch to repair small ventral hernias.

BACKGROUND: There is evidence that mesh repair for primary umbilical hernias results in less recurrences and similar wound complication rates compared to tissue repair. In recent years, several mesh devices for the repair of small ventral hernias have been developed, but some reports have been published on serious complications and adverse effects encountered with those mesh devices. METHODS: The Proceed™ Ventral Patch (PVP™) is a partially absorbable lightweight polypropylene mesh. We introduced PVP™ in our department in April 2009 and collected patient data and outcome in an observational study of 101 consecutive patients until December 2011 (Clinical.Trials.gov: NCT01307696). In addition to the routine control 3 weeks postoperative, prospective follow-up included a questionnaire, clinical investigation and ultrasound after 12 months. RESULTS: The study included 91 primary (76 umbilical/15 epigastric) and 10 incisional ventral hernias (including 6 trocar hernias). In all patients a PVP™ with a diameter of 6.4 cm was used. Wound problems were the most frequent complication (n = 18). Follow-up of at least 12 months was achieved in 98 patients (97 %) and the mean follow-up time was 15.9 months. Follow-up by clinical examination diagnosed a recurrence in 11/92 patients (12.0 %). Only four patients were aware of their recurrent hernia, the seven others reported no problems in the questionnaire. The additional ultrasound performed did not reveal recurrences that were not already diagnosed by clinical examination. In five patients a reoperation for repair of the recurrence was performed (reoperation rate 5/98 = 5.1 %). Hernia defect size (p = 0.032) and type of hernia (p = 0.029) were found to be a significant risk factors for development of a recurrent hernia (Fisher's exact test). Hernia size was a significant risk factor both in a univariate (p = 0.005) and in a multivariate Cox model (p = 0.017). Incisional hernia was of borderline significance in a univariate (p = 0.047) and in a multivariate Cox model (p = 0.08). CONCLUSION: Intensive clinical follow-up yields a high percentage (12.0 %) of clinically proven, but often asymptomatic recurrences after repair of small ventral hernias with the PVP™. Reoperation rate for recurrence was 5.1 %. Hernia defect size is a significant risk factor for recurrence. Therefore, we recommend using the PVP™ only for primary ventral hernias smaller than 2 cm. For larger or incisional hernias other techniques allowing the use of larger meshes is advocated.

Recommendations for reporting outcome results in abdominal wall repair: results of a Consensus meeting in Palermo, Italy, 28-30 June 2012.

BACKGROUND: The literature dealing with abdominal wall surgery is often flawed due to lack of adherence to accepted reporting standards and statistical methodology. MATERIALS AND METHODS: The EuraHS Working Group (European Registry of Abdominal Wall Hernias) organised a consensus meeting of surgical experts and researchers with an interest in abdominal wall surgery, including a statistician, the editors of the journal Hernia and scientists experienced in meta-analysis. Detailed discussions took place to identify the basic ground rules necessary to improve the quality of research reports related to abdominal wall reconstruction. RESULTS: A list of recommendations was formulated including more general issues on the scientific methodology and statistical approach. Standards and statements are available, each depending on the type of study that is being reported: the CONSORT statement for the Randomised Controlled Trials, the TREND statement for non randomised interventional studies, the STROBE statement for observational studies, the STARLITE statement for literature searches, the MOOSE statement for metaanalyses of observational studies and the PRISMA statement for systematic reviews and meta-analyses. A number of recommendations were made, including the use of previously published standard definitions and classifications relating to hernia variables and treatment; the use of the validated Clavien-Dindo classification to report complications in hernia surgery; the use of "time-to-event analysis" to report data on "freedom-of-recurrence" rather than the use of recurrence rates, because it is more sensitive and accounts for the patients that are lost to follow-up compared with other reporting methods. CONCLUSION: A set of recommendations for reporting outcome results of abdominal wall surgery was formulated as guidance for researchers. It is anticipated that the use of these recommendations will increase the quality and meaning of abdominal wall surgery research.

Human mastoid periosteum-derived stem cells: promising candidates for skeletal tissue engineering.

Currently, mesenchymal stem cells (MSCs) are considered as the most eligible cells for skeletal tissue engineering. However, factors such as difficult stimulation and control of differentiation in vivo hamper their clinical use. In contrast, periosteum or periosteum-derived cells (PCs) are routinely clinically applied for bone and cartilage repair. PCs have often been named MSCs but, although cells of osteochondrogenic lineages arise from MSCs, it is unclear whether periosteum really contains MSCs. Our aim was to investigate the MSC-like character of PCs derived from the periosteum of mastoid bone. Harvesting of periosteum from mastoid bone is easy, so mastoid represents a good source for the isolation of PCs. Therefore, we analysed the MSC-like growth behaviour and the expression of embryonic, ectodermal, endodermal and mesodermal markers by microarray and FACS technology, and the multilineage developmental capacity of human PCs. Regarding clinical relevance, experiments were performed in human serum-supplemented medium. We show that PCs do not express early embryonic stem cell markers such as Oct4 and Nanog, or the marker of haematopoietic stem cells CD34, but express some other MSC markers. Osteogenesis resulted in the formation of calcified matrix, increased alkaline phosphatase activity, and induction of the osteogenic marker gene osteocalcin. Staining of proteoglycans and deposition of type II collagen documented chondrogenic development. As shown for the first time, adipogenic stimulation of mastoid-derived PCs resulted in the formation of lipid droplets and expression of the adipogenic marker genes aP2 and APM1. These results suggest MSC-like PCs from mastoid as candidates for therapy of complex skeletal defects.

[The relevance of the inflammatory response in the injured brain]. / Die Bedeutung der posttraumatischen Entzündungsreaktion im verletzten Gehirn.

Research efforts in recent years have defined traumatic brain injury (TBI) as a predominantly immunological and inflammatory disorder. This perception is based on the fact that the overwhelming neuroinflammatory response in the injured brain contributes to the development of posttraumatic edema and to neuropathological sequelae which are, in large part, responsible for the adverse outcome. While the "key" mediators of neuroinflammation, such as the cytokine cascade and the complement system, have been clearly defined by studies in experimental TBI models, their exact pathways of interaction and pathophysiological implications remain to be further elucidated. This lack of knowledge is partially due to the concept of a "dual role" of the neuroinflammatory response after TBI. This notion implies that specific inflammatory molecules may mediate diverse functions depending on their local concentration and kinetics of expression in the injured brain. The inflammation-induced effects range from beneficial aspects of neuroprotection to detrimental neurotoxicity. The lack of success in pushing anti-inflammatory therapeutic concepts from"bench to bedside" for patients with severe TBI strengthens the further need for advances in basic research on the molecular aspects of the neuroinflammatory network in the injured brain. The present review summarizes the current knowledge from experimental studies in this field of research and discusses potential future targets of investigation.