STRONGHOLD first-year results of biomechanically calculated abdominal wall repair: a propensity score matching

PURPOSE

Every year around 70,000 people in Germany suffer from an abdominal incisional hernia that requires surgical treatment. Five years after reconstruction about 25% reoccur. Incisional hernias are usually closed with mesh using various reconstruction techniques, summarized here as standard reconstruction (SR). To improve hernia repair, we established a concept for biomechanically calculated reconstructions (BCR). In the BCR, two formulas enable customized patient care through standardized biomechanical measures. This study aims to compare the clinical outcomes of SR and BCR of incisional hernias after 1 year of follow-up based on the Herniamed registry.

METHODS

SR includes open retromuscular mesh augmented incisional hernia repair according to clinical guidelines. BCR determines the required strength (Critical Resistance to Impacts related to Pressure = CRIP) preoperatively depending on the hernia size. It supports the surgeon in reliably determining the Gained Resistance, based on the mesh-defect-area-ratio, further mesh and suture factors, and the tissue stability. To compare SR and BCR repair outcomes in incisional hernias at 1 year, propensity score matching was performed on 15 variables. Included were 301 patients with BCR surgery and 23,220 with standard repair.

RESULTS

BCR surgeries show a significant reduction in recurrences (1.7% vs. 5.2%, p = 0.0041), pain requiring treatment (4.1% vs. 12.0%, p = 0.001), and pain at rest (6.9% vs. 12.7%, p = 0.033) when comparing matched pairs. Complication rates, complication-related reoperations, and stress-related pain showed no systematic difference.

CONCLUSION

Biomechanically calculated repairs improve patient care. BCR shows a significant reduction in recurrence rates, pain at rest, and pain requiring treatment at 1-year follow-up compared to SR.

What are the influencing factors on the outcome in lateral incisional hernia repair? A registry-based multivariable analysis

Introduction

Incisional hernias following lateral abdominal wall incisions with an incidence of 1–4% are less common than following medial incisions at 14–19%. The proportion of lateral incisional hernias in the total collective of all incisional hernias is around 17%. Compared to midline defects, lateral incisional hernias are more difficult to repair because of the more complex anatomy and localization. A recent systematic review identified only 11 publications with a total of 345 patients reporting on lateral incisional hernia repair. Therefore, further studies are urgently needed.

Methods

Multivariable analysis of the data available for 6,306 patients with primary elective lateral incisional hernia repair was performed to assess the confirmatory pre-defined potential influence factors and their association with the perioperative and one-year follow-up outcomes.

Results

In primary elective lateral incisional hernia repair, open onlay, open IPOM and suture procedures were found to have an unfavorable effect on the recurrence rate. This was also true for larger defect sizes and higher BMI. A particularly unfavorable relationship was identified between larger defect sizes and perioperative complications. Laparoscopic-IPOM presented a higher risk of intraoperative, and open sublay of postoperative, complications. The chronic pain rates were especially unfavorably influenced by the postoperative complications, preoperative pain and female gender.

Conclusion

Open-onlay, open IPOM and suture procedures, larger defect sizes, female gender, higher BMI, preoperative pain and postoperative complications are associated with unfavorable outcomes following primary elective lateral incisional hernia repair.

P-002 PREOPERATIVE USE OF BOTULINUM TOXIN A FOR COMPLEX ABDOMINAL WALL HERNIAS: SIMPLIFICATION OF ANATOMICAL RECONSTRUCTION AND REDUCTION OF COMPONENT SEPARATION TECHNIQUES

Aim

Botulinum toxin A (BTA) may facilitate abdominal wall reconstruction for giant abdominal wall hernias. Complications after preoperative conditioning of the abdominal wall with BTA and subsequent surgical treatment have been poorly studied.

Methods

From 2018 to 2021, 31 patients with complex abdominal wall hernia were enrolled. Data were analyzed descriptively, risk factors, comorbidity, operative procedure, surgical site occurrences, and especially BTA-associated complications were documented. Key points were adverse effects, the rate of anatomical reconstruction, and reduction of component separation techniques.

Results

23 male and 8 female patients with a mean age of 62.7 years were included. The mean body mass index was 27.8 kg/m2. 61% had an ASA-Score over 3. The median duration of hospital stay was 11.6±5.2 days. The mean horizontal hernia defect was 13±5 cm, and the mean hernia gap area was 181.7±116 cm2. 83% were medial hernias with more than 10 cm hernia gap. Surgical reconstruction was performed using component separation techniques (CS) with mesh augmentation (61%), retromuscular sublay with CS (20%), and hybrid procedure (VAMOS) (9%). Complete closure of the anterior fascia was achieved in 100%. Anterior CS was necessary for 19%, and posterior CS was needed in 61%. The surgical site occurrences rate was 19%, with no BTA-associated complications. No hernia recurrence occurred during the follow-up period to date since 2018.

Conclusion

Preoperative conditioning of the lateral abdominal muscles with BTA seems to be a safe and effective method to facilitate tension-free anatomic reconstruction of the abdominal wall under the reduction of component separation.

P-034 RECOMMENDATIONS ON POSTOPERATIVE ACTIVITIES AFTER ABDOMINAL OPERATIONS AND INCISIONAL HERNIA REPAIR - A NATIONAL AND INTERNATIONAL SURVEY

Aim

There is no conclusive data on postoperative recommendations after abdominal and hernia surgery, and substantial variation in the literature. Thus, this study evaluates the status quo of recommendations of postoperative activity restriction after abdominal surgery.

Material and Methods

A national (German) and international survey (at the 41st EHS Annual Meeting) of general surgeons on postoperative recommendations after abdominal and hernia surgery was pooled and analyzed. Results 74.6% recommended postoperative reduced activity for 2 weeks or less after laparoscopy. For midline laparotomy, 48.8% considered a reduced activity of 4 weeks or less to be sufficient. A majority from the national survey recommended more than 4 weeks instead (60.2%), whereas only 31.5% from the international survey did so (p=0.000). In the pooled analysis, 258 of 450 (57.3%) rated 4 weeks or less suitable. However, the recommendations differed significantly between the surveys (4 weeks or less: a national survey, 47.1% vs. international survey, 64.6%; p=0.000).

Conclusion

There was substantial variation in the given recommendations. However, we found no evidence against immediate mobilization, reduced physical activity, and lifting for up to 2 weeks after laparoscopic surgery and for up to 4 weeks after open abdominal surgery and open incisional/ventral hernia repair in uncomplicated and standard cases. There might be individual and socio-economic benefits to allow patients to return to their whole personal level of activity and work without putting them at risk of complications. Due to lack of evidence, both retrospective and prospective, controlled studies are in need to develop reliable recommendations.

P-003 LATERAL ABDOMINAL HERNIAS: A REGISTRY-BASED MULTIVARIATE ANALYSIS OF SURGICAL TECHNIQUES AND OUTCOME

Aim

Data on lateral incisional hernia (LAH) repair is scarce. The operative therapy is challenging due to complex anatomy and bulging due to previous nerve lesions. Data concerning medial hernias are not necessarily transferable. Therefore, this study evaluates the status-quo of LAH repair, compares different strategies, and identifies risk factors for complications and adverse outcomes.

Materials and Methods

The German Herniamed registry was screened for LAH. Data from patients operated on between 01–05–2009 and 05–31–2020, resulting in 6,306 cases. Data analysis focused on patient-specific, surgery-related factors, complications, and outcome. In addition, a logistic regression analysis of multiple variables was conducted.

Results

Laparoscopic IPOM (27.9%) and open sublay (38.1%) were the most common surgical procedures. Intraoperative complications were more common in laparoscopic IPOM compared to open sublay (1.8% vs. 0.9%; p<0.001), whereas seroma rate was lower (1.8% vs. 3.4%; p<0.001). Open sublay showed a lower risk for intraoperative complications compared to laparoscopic IPOM (OR 0.298 [0.158–0.564]; p<0.001) in the regression analysis. Risk factors for recurrence were large defect size, open onlay/IPOM, and BMI.

Conclusion

LAH repair is especially challenging due to its anatomical complexity, rareness, and weak management evidence. This study adds registry-based data with the largest number of cases yet published. Due to the complexity and the flimsy evidence of treatment options, lateral incisional hernias should be treated in specialized hernia centers. In addition, further evaluation of repair techniques is needed, and particular focus should be put on a proper localization classification and defect size (both according to EHS).

OC-058 MORTALITY OF THE ELDERLY: ANALYSIS OF DATA FROM THE LAPARASTOMA REGISTRY

Aim

The therapeutic concept of open abdomen with temporary abdominal wall closure was introduced about 30 years ago. Since that time, various surgical strategies have been tried, continuously developed and established. In May 2015, a laparastoma registry was released in the form of an internet-based online platform.

Methods

Data from the laparastoma registry were analyzed and evaluated. The focus of the study was on the mortality of patients in the age group 75 years and older who underwent laparastoma treatment. Special attention was paid to the previous diseases, risk factors, MPI.

Results

913 patients with open abdomen and subsequent laparastomy treatment were enrolled in the laparastomy registry from 2015 to 2022. 65% of patients were male. 69.6% had secondary diseases. The indications for laparastoma establishment were peritonitis (37.2%, N=340), trauma (9.2%, n=84), abdominal compartment (18.1%, n=165) and others. The overall mortality rate was 28.7%. The mortality rate in the group between 75 and 80 years (n=155) was 36% (OR= 1.445 [CI: 1.002–2.008]; p=0.049). The mortality rate in patients older than 75 years (n=67) was 40.3% (OR 1.680 CI 1.008–2.802; p=0.047).

Conclusion

In the evaluation, three key questions were raised and analyzed by the study: what is the mortality in the elderly patients under laparastoma treatment, what is the mortality in the patients over 75 years old? What are the leading risk factors in the two groups.

Recommendations on postoperative strain and physical labor after abdominal and hernia surgery: an expert survey of attendants of the 41st EHS Annual International Congress of the European Hernia Society

BACKGROUND

There are no valid recommendations or reliable guidelines available to guide patients how long they should refrain from lifting weights or returning to heavy physical labor after abdominal or hernia surgery. Recent studies found that surgeons' recommendations not to be evidence-based and might be too restrictive considering data on fascial healing and incisional hernia development. It is likely that this impairs the patient's quality of life and leads to remarkable socio-economic costs. Hence, we conducted this survey to gather international expert's opinions on this topic.

MATERIALS AND METHODS

At the 41st Annual International Congress of the EHS, attending international experts were asked to complete a questionnaire concerning recommendations on given proposals for postoperative refrain from heavy work or lifting after abdominal surgery and also after hernia repairs.

RESULTS

In total, 127 experts took part in the survey. 83.9% were consultants with a mean experience since specialization of more than 11 years. Two weeks of no heavy physical strain after laparoscopic surgery were considered sufficient by more than 50% of the participants. For laparotomy, more than 50% rated 4 weeks appropriate. For mesh-augmented sublay and IPOM repair of ventral or incisional hernias, more than 50% rated 4 weeks of rest appropriate. For complex hernia repair, 37% rated 4 weeks reasonable. Two weeks after, groin hernia surgery was considered sufficient by more than 50% of the participants.

CONCLUSION

Following groin hernia repair (Lichtenstein/endoscopic technique) and laparoscopic operation, the majority agreed on the proposal of 2 weeks refraining from physical strain. Four weeks of no physical strain were considered appropriate by a majority after laparotomy and open incisional hernia repair. However, the results showed substantial variation in the ratings, which indicates uncertainty even in this selected cohort of hernia surgery experts and emphasizes the need for further scientific evaluation. This is particularly remarkable, because a lack of evidence that early postoperative strain leads to higher incisional hernia rates.

TRIAL REGISTRATION

Number DRKS00023887.

Prognostic significance of high mobility group A2 (HMGA2) in pancreatic ductal adenocarcinoma: malignant functions of cytoplasmic HMGA2 expression

PURPOSE

HMGA2 has frequently been found in benign as well as malignant tumors and a significant association between HMGA2 overexpression and poor survival in different malignancies was described. In pancreatic ductal adenocarcinoma (PDAC), nuclear HMGA2 expression is associated with tumor dedifferentiation and presence of lymph node metastasis. Nevertheless, the impact of HMGA2 occurrence in other cell compartments is unknown.

METHODS

Intracellular distribution of HMGA2 was analyzed in PDAC (n = 106) and peritumoral, non-malignant ducts (n = 28) by immunohistochemistry. Findings were correlated with clinico-pathological data. Additionally, intracellular HMGA2 presence was studied by Western blotting of cytoplasmic and nuclear fractions of cultured cells.

RESULTS

HMGA2 was found in the cytoplasm and in the nucleus of cultured cells. In human tumor tissue, HMGA2 was also frequently found in the cytoplasm and the nucleus of tumor cells, however, nuclear staining was generally stronger. Direct comparison from tumor tissue with corresponding non-neoplastic peritumoral tissue revealed significantly stronger expression in tumors (p = 0.003). Of note, the nuclear staining was significantly stronger in lymph node metastatic cell nuclei compared to primary tumor cell nuclei (p = 0.049). Interestingly, cytoplasmic staining positively correlated with lymph vessel (p = 0.004) and venous invasion (p = 0.046).

CONCLUSION

HMGA2 is a prognostic marker in PDAC. Firstly, we found a positive correlation for cytoplasmic HMGA2 expression with lympho-vascular invasion and, secondly, we found a significantly stronger nuclear expression of HMGA2 in cancer-positive lymph node nuclei compared to primary tumor cell nuclei. So far, the role of cytoplasmic HMGA2 is nearly unknown, however, our data lend support to the hypothesis that cytoplasmic HMGA2 expression is involved in nodal spread.

[Advanced training of general and visceral surgeons in life-saving emergency surgery : Results of a survey among participants of a surgery course]

Hintergrund

Die geringe Anzahl operativ zu versorgender Körperhöhlenverletzungen erfordert ein Umdenken in der chirurgischen Aus- und Weiterbildung. Ein entsprechendes Kursformat wird seit 2014 über die DGAV angeboten. Um Berechtigung, Bedarf, Nutzen und Erfolg eines solchen Kursformates zu erheben, erfolgte eine Evaluation durch die bisherigen Kursteilnehmer.

Material und Methoden

Kursevaluation und zusätzliche Onlinebefragung der bisherigen Kursteilnehmer hinsichtlich Alter, Geschlecht, Ausbildungsstand, Fachrichtung, Versorgungsstufe des Krankenhauses, notfallchirurgischer Erfahrungen, der Häufigkeit chirurgischer Notfallversorgungen, Teilnahme an anderen Kursformaten, Erfahrungen nach der Kursteilnahme, Einschätzung der aktuellen Fort- und Weiterbildungssituation und Finanzierung solcher Kurse.

Ergebnisse

Insgesamt 142 Kursteilnehmer evaluierten ihre Kursteilnahme, zusätzlich beantworteten 83 den Onlinefragebogen. Über 90 % berichteten von einem nachhaltigen positiven Einfluss des Kurses auf ihr notfallchirurgisches Handeln. Mehr als die Hälfte konnte von konkreten Notfallsituationen berichten, die sie aufgrund der Kursteilnahme besser bewältigen konnten. In der Notfallversorgung erfahrene Chirurgen bewerteten den eigenen Lernerfolg durch die Kursteilnahme signifikant häufiger positiv als ihre weniger erfahrenen Kollegen. Keinen Einfluss auf den Lernerfolg hatten eine Ober- oder Chefarztposition, die Versorgungsstufe des Krankenhauses, das Alter oder Geschlecht der Teilnehmer. Die Mehrheit der antwortenden Chirurgen befürwortet die Integration eines solchen Kursformates in die chirurgische Weiterbildung und fordert hierzu eine finanzielle Unterstützung.

Schlussfolgerung

Kursformate, in denen notfallchirurgische Strategien und Fähigkeiten vermittelt werden, sind etabliert und werden sehr positiv evaluiert. Die Fort- und Weiterbildung in notfallchirurgischen Fähigkeiten und Kenntnissen liegt im gesellschaftlichen Interesse und zumindest anteilig auch in ihrer Verantwortung.

TRAIL Induces Nuclear Translocation and Chromatin Localization of TRAIL Death Receptors

Binding of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to the plasma membrane TRAIL-R1/-R2 selectively kills tumor cells. This discovery led to evaluation of TRAIL-R1/-R2 as targets for anti-cancer therapy, yet the corresponding clinical trials were disappointing. Meanwhile, it emerged that many cancer cells are TRAIL-resistant and that TRAIL-R1/-R2-triggering may lead to tumor-promoting effects. Intriguingly, recent studies uncovered specific functions of long ignored intracellular TRAIL-R1/-R2, with tumor-promoting functions of nuclear (n)TRAIL-R2 as the regulator of let-7-maturation. As nuclear trafficking of TRAIL-Rs is not well understood, we addressed this issue in our present study. Cell surface biotinylation and tracking of biotinylated proteins in intracellular compartments revealed that nTRAIL-Rs originate from the plasma membrane. Nuclear TRAIL-Rs-trafficking is a fast process, requiring clathrin-dependent endocytosis and it is TRAIL-dependent. Immunoprecipitation and immunofluorescence approaches revealed an interaction of nTRAIL-R2 with the nucleo-cytoplasmic shuttle protein Exportin-1/CRM-1. Mutation of a putative nuclear export sequence (NES) in TRAIL-R2 or the inhibition of CRM-1 by Leptomycin-B resulted in the nuclear accumulation of TRAIL-R2. In addition, TRAIL-R1 and TRAIL-R2 constitutively localize to chromatin, which is strongly enhanced by TRAIL-treatment. Our data highlight the novel role for surface-activated TRAIL-Rs by direct trafficking and signaling into the nucleus, a previously unknown signaling principle for cell surface receptors that belong to the TNF-superfamily.

Impact of p53 status on TRAIL-mediated apoptotic and non-apoptotic signaling in cancer cells

Due to their ability to preferentially induce cell death in tumor cells, while sparing healthy cells, TNF-related apoptosis-inducing ligand (TRAIL) and agonistic anti-TRAIL-R1 or anti-TRAIL-R2-specific antibodies are under clinical investigations for cancer-treatment. However, TRAIL-Rs may also induce signaling pathways, which result in malignant progression. TRAIL receptors are transcriptionally upregulated via wild-type p53 following radio- or chemotherapy. Nevertheless, the impact of p53 status on the expression and signaling of TRAIL-Rs is not fully understood. Therefore, we analyzed side by side apoptotic and non-apoptotic signaling induced by TRAIL or the agonistic TRAIL-R-specific antibodies Mapatumumab (anti-TRAIL-R1) and Lexatumumab (anti-TRAIL-R2) in the two isogenic colon carcinoma cell lines HCT116 p53^+/+ and p53^-/-. We found that HCT116 p53^+/+ cells were significantly more sensitive to TRAIL-R-triggering than p53^-/- cells. Similarly, A549 lung cancer cells expressing wild-type p53 were more sensitive to TRAIL-R-mediated cell death than their derivatives with knockdown of p53. Our data demonstrate that the contribution of p53 in regulating TRAIL-R-induced apoptosis does not correlate to the levels of TRAIL-Rs at the plasma membrane, but rather to p53-mediated upregulation of Bax, favouring the mitochondrial amplification loop. Consistently, stronger caspase-9 and caspase-3 activation as well as PARP-cleavage was observed following TRAIL-R-triggering in HCT116 p53^+/+ compared to HCT116 p53^-/- cells. Interestingly, HCT116 p53^+/+ cells showed also a more potent activation of non-canonical TRAIL-R-induced signal transduction pathways like JNK, p38 and ERK1/ERK2 than p53^-/- cells. Likewise, these cells induced IL-8 expression in response to TRAIL, Mapatumumab or Lexatumumab significantly stronger than p53^-/- cells. We obtained similar results in A549 cells with or without p53-knockdown and in the two isogenic colon cancer cell lines RKO p53^+/+ and p53^-/-. In both cellular systems, we could clearly demonstrate the potentiating effects of p53 on TRAIL-R-mediated IL-8 induction. In conclusion, we found that wild-type p53 increases TRAIL-R-mediated apoptosis but simultaneously augments non-apoptotic signaling.

The novel TRAIL-receptor agonist APG350 exerts superior therapeutic activity in pancreatic cancer cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has raised attention as a novel anticancer therapeutic as it induces apoptosis preferentially in tumor cells. However, first-generation TRAIL-receptor agonists (TRAs), comprising recombinant TRAIL and agonistic receptor-specific antibodies, have not demonstrated anticancer activity in clinical studies. In fact, cancer cells are often resistant to conventional TRAs. Therefore, in addition to TRAIL-sensitizing strategies, next-generation TRAs with superior apoptotic activity are warranted. APG350 is a novel, highly potent TRAIL-receptor agonist with a hexavalent binding mode allowing the clustering of six TRAIL-receptors per drug molecule. Here we report on preclinical in vitro and in vivo studies testing the activity of APG350 on pancreatic ductal adenocarcinoma (PDAC) cells. We found that APG350 potently induced apoptosis of Colo357, PancTuI and Panc89 cells in vitro. In addition, APG350 treatment activated non-canonical TRAIL signaling pathways (MAPK, p38, JNK, ERK1/ERK2 and NF-κB) and induced the secretion of IL-8. Stable overexpression of Bcl-xL inhibited APG350-induced cell death and augmented activation of non-canonical pathways. Intriguingly, pre-treatment of Bcl-xL-overexpressing cells with the BH3-mimic Navitoclax restored their sensitivity to APG350. To study the effects of APG350 on PDAC cells in vivo, we applied two different orthotopic xenotransplantation mouse models, with and without primary tumor resection, representing adjuvant and palliative treatment regimes, respectively. APG350 treatment of established tumors (palliative treatment) significantly reduced tumor burden. These effects, however, were not seen in tumors with enforced overexpression of Bcl-xL. Upon primary tumor resection and subsequent APG350 treatment (adjuvant therapy), APG350 limited recurrent tumor growth and metastases. Importantly, therapeutic efficacy of APG350 treatment was more effective compared with treatment with soluble TRAIL in both models. In conclusion, APG350 represents a promising next-generation TRA for the treatment of PDAC. Moreover, our results suggest that combining APG350 with Navitoclax might be a succesfull strategy for cancers harboring mitochondrial apoptosis resistance.

Intensive care and health outcomes of open abdominal treatment: long-term results of vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM)

PURPOSE

The study's purpose is to evaluate the long-term outcome after vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM) and to identify predictors of quality of life associated with intensive care.

METHODS

Fifty-five patients who underwent open abdomen management at our institution from 2006 to 2013 were prospectively enrolled in this study. After a median follow-up period of 3.8 years, 27 patients completed the 36-Item Short Form Survey (SF-36) quality of life questionnaire. As this is a report solely focused on quality of life, direct treatment-related outcome measures like mortality, closure rates, and incisional hernia development of this study cohort have been reported previously.

RESULTS

 = 0.50, β = -0.70, p = 0.02).

CONCLUSIONS

Despite high short-term mortality and morbidity rates for these critically ill patients, open abdomen treatment using VAWCM allows patients to recover to an acceptable long-term quality of life. The complex intensive care score can be used as a surrogate parameter for the global severity of illness and was the only predictor of physical functioning (SF-36).

The Open Abdomen Route by EuraHS: introduction of the data set and initial results of procedures and procedure-related complications

INTRODUCTION

Open abdomen management has become a well-established strategy in the treatment of serious intra-abdominal pathologies. Key objectives are fistula prevention and high fascial closure rates. The current level of evidence on laparostoma is insufficient. This is due to the rareness of laparostomas, the heterogeneity of study cohorts, and broad diversity of techniques. Collecting data in a standardised, multicentre registry is necessary to draw up evidence-based guidelines.

MATERIALS AND METHODS

In order to improve the level of evidence on laparostomy, CAMIN (surgical working group for military and emergency surgery) of DGAV (German Society for General and Visceral Surgery), initiated the implementation of a laparostomy registry. This registry was established as the Open Abdomen Route by EuraHS (European Registry of Abdominal Wall Hernias). Key objectives include collection of data, quality assurance, standardisation of therapeutic concepts and the development of guidelines. Since 1 May 2015, the registry is available as an online database called Open Abdomen Route of EuraHS (European Registry of Abdominal Wall Hernias). It includes 11 categories for data collection, including three scheduled follow-up examinations.

RESULTS

As part of this pilot study, all entries of the first 120 days were analysed, resulting in a review of 82 patients. At 44%, secondary peritonitis was the predominant indication. The mortality rate was 22%. A comparison of methods with and without fascial traction reveals fascial closure rates of 67% and 25%, respectively (intention-to-treat analysis, p < 0.03). Inert visceral protection was used in 67% of patients and achieved a small bowel fistula incidence of only 5.5%.

DISCUSSION

Optimising laparostomy management techniques in order to achieve low incidence of fistulation and high fascial closure rates is possible. The method that ensures the best possible outcome-based on current evidence-would involve fascial traction, visceral protection and negative pressure. The laparostomy registry is a useful tool for quickly generating sufficient evidence for open abdomen treatment.

Abdominal wall integrity after open abdomen: long-term results of vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM)

PURPOSE

The open abdomen has become a standard technique in the management of critically ill patients undergoing surgery for severe intra-abdominal conditions. Negative pressure and mesh-mediated fascial traction are commonly used and achieve low fistula rates and high fascial closure rates. In this study, long-term results of a standardised treatment approach are presented.

METHODS

Fifty-five patients who underwent OA management for different indications at our institution from 2006 to 2013 were enrolled. All patients were treated under a standardised algorithm that uses a combination of vacuum-assisted wound closure and mesh-mediated fascial traction. Structured follow-up assessments were offered to patients and included a medical history, a clinical examination and abdominal ultrasonography. The data obtained were statistically analysed.

RESULTS

The fascial closure rate was 74 % in an intention-to-treat analysis and 89 % in a per-protocol analysis. The fistula rate was 1.8 %. Thirty-four patients attended follow-up. The median follow-up was 46 months (range 12-88 months). Incisional hernias developed in 35 %. Patients with hernias needed more operative procedures (10.3 vs 3.4, p = 0.03) than patients without hernia formation. A Patient Observer Scar Assessment Scale (POSAS) of 31.1 was calculated. Patients with symptomatic hernias (NAS of 2-10) had a significantly lower mean POSAS score (p = 0.04).

CONCLUSIONS

Vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM) seem to result in low complication rates and high fascial closure rates. Abdominal wall reconstruction, which is a challenging and complex procedure and causes considerable patient discomfort, can thus be avoided in the majority of cases. Available results are based on studies involving only a small number of cases. Multi-centre studies and registry-based data are therefore needed to validate these findings.

Small Bowel Fistulas and the Open Abdomen

Over the last 15 years, the contemporary strategies to treat the open abdomen have reduced the lethal complications. Systematic intensive care and modern wound management in conjunction with a plastic barrier to protect the viscera and topical negative pressure on the soft tissues have reduced the development of small bowel fistulas. The literature selected for this review shows that the surgical handling of the exposed bowel, the choice of the material for temporary coverage and early progressive closure of the defect are crucial for the prevention of fistulas. At present, surgeons worldwide have adopted these principles leading to an increase of primary or delayed closure rates. When a small fistula occurs, biological dressings like human acellular dermal matrix and fibrin glue may help to seal the orifice and to treat the patient conservatively. In case of a large fistula, vacuum-assisted wound management is recommended as well. Through a separate hole in the vacuum sponge matching to the fistula, the enteric contents are sucked off while the wound bed heals and is prepared for split thickness skin graft. Surgical resection of established fistula unresponsive to conservative measures should only be performed on patients well-nourished and free of infection with a delay of at least six months. for patients with an open abdomen, surgical expertise and a well-structured management plan offer the best chances to overcome this potentially devastating condition — with or without fistula.

[Evaluation of interest in research among surgically active medical officers in the German Armed Forces]

BACKGROUND

Research in military medicine and in particular combat surgery is a broad field that has gained international importance during the last decade. In the context of increased NATO missions, this also holds true for the Bundeswehr (German Armed Forces); however, medical officers in surgery must balance research between their clinical work load, missions, civilian and family obligation.

MATERIAL AND METHODS

To evaluate engagement with and interest in research, a questionnaire was distributed among the doctors of the surgical departments of the Bundeswehr hospitals by the newly founded working group Chirurgische Forschung der Bundeswehr (surgical research of the Bundeswehr). Returned data were recorded from October 2013 to January 2014 and descriptive statistics were performed.

RESULTS

Answers were received from 87 out of 193 military surgeons (45 %). Of these 81 % announced a general interest in research with a predominance on clinical research in preference to experimental settings. At the time of the evaluation 32 % of the participants were actively involved in research and 53 % regarded it as difficult to invest time in research activities parallel to clinical work. Potential keys to increase the interest and engagement in research were seen in the implementation of research coordinators and also in a higher amount of free time, for example by research rotation.

CONCLUSION

Research can be regarded as having a firm place in the daily work of medical officers in the surgical departments of the Bundeswehr; however, the engagement is limited by time and structural factors. At the departmental level and in the command structures of the military medical service, more efforts are recommended in the future in order to enhance the engagement with surgical research. This evaluation should be repeated in the coming years as a measuring instrument and data should be compared in an international context.

[Gunshot and stab wounds in Germany--epidemiology and outcome: analysis from the TraumaRegister DGU®]

BACKGROUND

The management of gunshot wounds is a rare challenge for trauma surgeons in Germany and Central Europe as a result of the low incidence of this type of trauma. Penetrating injuries occur with an incidence of 5% in Germany. They are caused by gunshots or more commonly by knives or other objects, for example during accidents. Since even the number of patients who are treated at level 1 trauma centres is limited by the low incidence, the objective of this study was to assess the epidemiology and outcome of gunshot and stab wounds in Germany.

MATERIAL AND METHODS

Since 2009, the trauma registry of the German Trauma Society (TraumaRegister DGU®) has been used to assess not only whether a trauma was penetrating but also whether it was caused by a gunshot or a stabbing. On the basis of this registry, we identified relevant cases and defined the observation period. Data were taken from the standard documentation forms that participating German hospitals completed between 2009 and 2011. We did not specify exclusion criteria in order to obtain as comprehensive a picture as possible of the trauma entities investigated in this study. As a result of the high incidence of gunshot wounds to the head and the implications of this type of injury for the entire group, a subgroup of patients without head injuries was analysed.

RESULTS

From 2009 to 2011, there were 305 patients with gunshot wounds and 871 patients with stab wounds. The high proportion of suicide-related gunshot wounds to the head resulted in a cumulative mortality rate of 39.7%. Stab wounds were associated with a lower mortality rate (6.2%). Every fourth patient with a gunshot or stab wound presented with haemorrhagic shock, which was considerably more frequently seen during the prehospital phase than during the inhospital phase of patient management. Of the patients with gunshot wounds, 26.9% required transfusions. This percentage was three times higher than that for patients with blunt trauma.

CONCLUSION

In Germany, gunshot and stab wounds have a low incidence and are mostly caused by violent crime or attempted suicide. Depending on the site of injury, they have a high mortality and are often associated with major haemorrhage. As a result of the low incidence of these types of trauma, further data and analyses are required which can provide the basis for an evaluation of the long-term quality of the management of patients with stab or gunshot wounds.

[Gunshot wounds: should projectiles and fragments always be removed?]

BACKGROUND

Projectiles or metal fragments can remain lodged in the body of victims of gunshot injuries. This also applies to projectiles which do not tend to deform or fragment on impact. When a projectile fragments on penetration, jacket or lead core particles are likely to remain lodged in the affected region even if the projectile has exited the body.

AIM OF THE STUDY

A frequently asked question in the surgical management of such injuries is whether there are medical indications for the surgical removal of projectiles or fragments.

MATERIAL AND METHODS

This article presents some typical cases of patients who have received treatment at our institution and reviews the pertinent literature to show general recommendations in special cases concerning the removal of projectiles or fragments and when additional surgical trauma is justified. Parameters for decision making are presented in an algorithm.

RESULTS

From our own patients, 5 with remaining fragments in the soft tissue were invited for a clinical follow up. Serum probes and 24 h urine output was analysed for serum lead levels and urinary aminolevulinic acid levels. 74 months (max. 128 - min. 42 months) after injury we documented not elevated serum lead levels of 8.25 μg/ml and urinary aminolevulinic acid levels of 4.8 mg/24 h.

DISCUSSION

When lead-containing projectiles or fragments remain lodged in the body, monitoring is required and includes the measurement of serum lead levels and urinary aminolevulinic acid levels. The most important clinical symptoms of lead poisoning are gastrointestinal and neurological in nature. The treatment of choice for lead poisoning is the administration of chelating agents and removal of the lead source by surgical intervention.

Management of the open abdomen using vacuum-assisted wound closure and mesh-mediated fascial traction

BACKGROUND

The open abdomen has become an accepted treatment option of critically ill patients with severe intra-abdominal conditions. Fascial closure is a particular challenge in patients with peritonitis. This study investigates whether fascial closure rates can be increased in peritonitis patients by using an algorithm that combines vacuum-assisted wound closure and mesh-mediated fascial traction. Moreover, fascial closure rates for patients with peritonitis, trauma or abdominal compartment system (ACS) are compared.

METHODS

Data were collected prospectively from all patients who underwent open abdomen management at our institution from 2006 to 2012. All patients were treated under a standardised algorithm that combines vacuum-assisted closure and mesh placement at the fascial level.

RESULTS

During the study period, 53 patients (mean age 53 years) underwent open abdomen management for a mean duration of 15 days. Indications for leaving the abdomen open were peritonitis (51 %), trauma (26 %), and ACS or abdominal wall dehiscence (23 %). The fascial closure rate was 79 % in an intention-to-treat analysis and 89 % in a per-protocol analysis. Mortality was 13 %. No patient developed an enteroatmospheric fistula or abdominal wall dehiscence after closure. The mean duration of treatment was significantly longer in peritonitis patients (20 days) than in patients without peritonitis (10 days) (p = 0.03). There were no significant differences in fascial closure rates between patients with peritonitis (87 %), trauma (85 %), and ACS or abdominal wall dehiscence (100 %) (p = 0.647).

CONCLUSIONS

Regardless of the underlying pathology, high fascial closure rates can be achieved using a combination of vacuum-assisted closure and mesh-mediated fascial traction.

[Laparoscopy for abdominal trauma]

With increasing experience in minimally invasive surgery, laparoscopy's role in abdominal trauma can be defined exactly. Main exclusion criteria are hemodynamic instability and increased intracranial pressure. A literature review of 1996 to 2006 reveals perforating injury mainly of the left thoracoadominal area as the most important indication for laparoscopy . Its goal is to determine intraperitoneal lesions and integrity of the abdominal wall and diaphragm. Minor injuries of the parenchymatous organs and diaphragm can be successfully repaired laparoscopically. In blunt abdominal trauma, laparoscopy is used as a complementary diagnostic device in case ultrasound and multislice CT show unclear findings and the patient's clinical status requires invasive measures. The clear weakness of laparoscopy in abdominal trauma is its inability to identify reliably hollow viscus perforation and retroperitoneal injury. In this, sensitivity is only 25%. In case of proven lesions of the gastrointestinal tract, conversion to laparotomy is to be considered. Despite the reports on laparoscopic treatment, open repair of hollow organ injuries is still to be recommended.

[Management of recurrent inguinal hernia after previous mesh repair: a challenge]

INTRODUCTION

Since the use of prosthetic mesh for the surgical repair of inguinal hernias has become increasingly popular, mesh material introduced during a previous operation is being detected in a growing number of patients undergoing surgery for recurrent hernia. This applies to at least 10% of recurrences. Needed is a therapeutic algorithm for the surgical management of recurrent hernias after previous mesh repair.

MATERIAL AND METHODS

A total of 672 recurrent hernia repairs performed in hospitals in the German cities Aachen and Koblenz were analysed in order to review clinical practice. In 92 patients (13.7%) who underwent surgery for recurrent hernia, mesh had been used in the previous hernia repairs. Attention was focused on the location of the recurrence in relation to the site of mesh implantation and on the advantages and disadvantages of the various surgical procedures for repairing recurrent hernias. Re-examination was performed with a mean follow-up of 3 years.

RESULTS

Surgeons mostly decided during operation which procedure to use. A transinguinal approach was preferred for patients presenting with recurrent hernia and pain, and mesh material introduced during a previous operation was then explanted. In the case of multiple recurrences, a minimal direct suture repair was used for small defects or a preperitoneal approach for inserting a new, large mesh. The majority of recurrences were medial or suprapubic, especially those occurring after a Lichtenstein repair. After re-examining 87 of 92 patients, nine recurrences (10.3%) were found. Mesh-free suturing methods were affected most frequently. Moderate complaints were reported by 39.1%, and 4.6% suffered from medical chronic pain.

CONCLUSION

The surgical management of recurrent hernias after previous mesh repair is a particular challenge for surgeons. We introduce a therapeutic algorithm for recurrent hernia surgery after previous mesh implantation based on analysis of clinical practice.

Less chronic pain following mesh fixation using a fibrin sealant in TEP inguinal hernia repair

Endoscopic hernia repair methods have become increasingly popular over the past 15 years. The postulated main advantages of the endoscopic technique are less postoperative pain, early recovery and lower recurrence rates. Fixation of the endoscopic mesh seems to be necessary to minimize the risk of recurrence. Stapling has been implicated to cause chronic inguinal pain syndromes. We performed a retrospective study on male patients who were endoscopically operated on primary inguinal hernias. Our aim was to clarify whether mesh fixation using a fibrin sealant is as safe and reliable as conventional stapling. Additionally, we compared the prevalence of chronic inguinal pain. A standardized population of 133 male patients (mean age 55.9 years) with 186 (80 unilateral; 53 bilateral) consecutive primary laparoscopic total extraperitoneal inguinal hernia repairs was assigned to two groups, depending on whether stapling or a fibrin sealant had been used for mesh fixation. A retrospective case control study was performed to conduct statistical analysis based on the following parameters: recurrence, complications, chronic inguinal pain, foreign body sensation and numbness. Hernia repairs numbering 173 (staples n=87; fibrin n=86) were followed up for a mean duration of 23.7 (11-47) months. The prevalence of chronic inguinal pain was significantly (P=0.002; Fisher exact test) higher in the stapled group-20.7% than in the fibrin sealant group with a prevalence of 4.7%. In terms of recurrence rate, complications and foreign body sensation, fewer patients were affected in the fibrin group than in the reference population, although the differences were not statistically significant. There were no major complications in either of the groups. The mean postoperative stay in hospital was 1.4 days. Fibrin sealing is as effective as stapling in providing secure mesh fixation. The fibrin group displayed a statistically significant lower prevalence of chronic pain syndromes. Mesh sealing provides adequate fixation and reduces the risk of chronic inguinal pain as a complication of the intervention.

Bifurcation, bursting, and spike frequency adaptation

Many neural systems display adaptive properties that occur on time scales that are slower than the time scales associated with repetitive firing of action potentials or bursting oscillations. Spike frequency adaptation is the name given to processes that reduce the frequency of rhythmic tonic firing of action potentials, sometimes leading to the termination of spiking and the cell becoming quiescent. This article examines these processes mathematically, within the context of singularly perturbed dynamical systems. We place emphasis on the lengths of successive interspike intervals during adaptation. Two different bifurcation mechanisms in singularly perturbed systems that correspond to the termination of firing are distinguished by the rate at which interspike intervals slow near the termination of firing. We compare theoretical predictions to measurement of spike frequency adaptation in a model of the LP cell of the lobster stomatogastric ganglion.

Automated Feulgen staining with a temperature-controlled staining machine

A Shandon Varistain 24-3 staining machine was modified in order to run automated DNA Feulgen staining. Initial studies showed a strict dependence of the staining intensity (integrated optical density [IOD]) on the temperature of the DNA hydrolysis in 4 N HCl: a difference of 0.5 degrees C around the optimum hydrolysis temperature of 27.5 degrees C resulted in IOD differences of up to 7.8% in epithelial cells and up to 12.0% in lymphocytes. A temperature-controlled stainless steel cuvette, covered with a 4 N HCl-resistant material, was developed and integrated into the machine. Temperature measurements were performed at different positions in the cuvette and on glass slides with copper-constantan electrodes fixed on them; no temperature gradient could be detected within the cuvette. The adjusted temperature of 27.5 degrees C remained constant over 24 hours. The coefficient of variation (CV) of the staining intensity in lymphocytes between different areas on the same slide and between different slides of the same staining cycle was less than 0.6%. The CV between different staining cycles was 5.9%. This system for automated Feulgen staining thus gives reproducible and reliable results and may be introduced into routine diagnostic procedures.