Narbenhernien

Systematic review and meta-analysis of the incidence of incisional hernia in urological surgery

PURPOSE

To evaluate the incidence of incisional hernia in patients undergoing direct access to the abdominal cavity in urological surgery.

METHODS

We conducted a systematic review in Pubmed, Embase, and Cochrane Central from 1980 to the present according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. Eighty-four studies were selected for inclusion in this analysis, and meta-analysis and meta-regression were performed.

RESULTS

The total incidence in the 84 studies was 4.8% (95% CI 3.7% - 6.2%) I2 93.84%. Depending on the type of incision, it was higher in the open medial approach: 7.1% (95% CI 4.3%-11.8%) I2 92.45% and lower in laparoscopic surgery: 1.9% (95% CI 1%-3.4%) I2 71, 85% According to access, it was lower in retroperitoneal: 0.9% (95% CI 0.2%-4.8%) I2 76.96% and off-midline: 4.7% (95% CI 3.5%-6.4%) I2 91.59%. Regarding the location of the hernia, parastomal hernias were more frequent: 15.1% (95% CI 9.6% - 23%) I2 77.39%. Meta-regression shows a significant effect in reducing the proportion of hernias in open lateral, laparoscopic and hand-assisted compared to medial open access.

CONCLUSION

The present review finds the access through the midline and stomas as the ones with the highest incidence of incisional hernia. The use of the lateral approach or minimally invasive techniques is preferable. More prospective studies are warranted to obtain the real incidence of incisional hernias and evaluate the role of better techniques to close the abdomen.

Subcuticular sutures versus staples for skin closure in patients undergoing abdominal surgery: A meta-analysis of randomized controlled trials

Background

Surgical site infections (SSIs) are common postoperative complications. Whether the use of staples or sutures makes a difference in abdominal surgery’s infection rate remains elusive.

Methods

A systematic review was performed to identify randomized clinical trials comparing staples and sutures after abdominal surgeries. Eligibility criteria involved the SSI occurrence as the primary outcome and the incidence of wound dehiscence, closure time, cosmesis, and patient satisfaction as the secondary outcomes.

Results

Of the 278 studies identified, seven randomized controlled trials representing 3705 patients were included in this review. There was no significant difference in SSI rates between sutures and staples in general (OR = 0.98, 95% CI = 0.79–1.22, I² = 44%, P = 0.1) or in a subgroup of gastrointestinal surgery, where subcuticular suturing was found with a comparable SSI risk with skin stapling (OR = 0.85, 95% CI = 0.66–1.09). Staple closure was associated with a shorter surgery duration, whereas sutures appeared to provide better cosmesis and patient satisfaction. Sutures and staples achieved a comparable incidence of dehiscence. There was no significant between-study publication bias.

Conclusion

Our study demonstrated similar outcomes in SSI rate between subcuticular sutures and staples for skin closure in patients undergoing abdominal surgery.

Video-Assisted Mini-Open Sublay (VAMOS): A Simple Hybrid Approach for Lateral Incisional Hernias

Purpose

The purpose is to present a new hybrid approach of lateral incisional hernia repair associated with reduced operative trauma and anatomically optimal mesh placement.

Methods

Video-Assisted Mini-Open Sublay (VAMOS) consists of a laparoscopic atraumatic dissection of the hernia sac, diaphanoscopy, laparoscopically-assisted closure of the fascial gap and mesh placement in sublay position through a minimized skin incision. Feasibility of this concept was assessed in a cohort of 7 consecutive patients.

Results

VAMOS approach was feasible in all 7 patients. Median hernia size was 8 cm, the median skin incision width was 7.7 cm. Median operative time was 86 min. In all patients a sufficient mesh overlap on all sides of the fascial gap was ensured. On short-term follow-up no procedure related complications were recorded, seroma formation occurred in 2 patients. Pain medication was necessary for median 4.9 days. There was no need for pain medication on day 14, whatsoever.

Conclusion

Initial VAMOS results show that the technique is simple, time-saving and safe. It provides a substantial reduction in postoperative pain compared to an open approach. Through implantation in the intermuscular sublay position and minor access-related trauma, it is possible to achieve a biomechanically optimal mesh position, to lay the foundations for adequate remodelling of the abdominal wall, and to prevent recurrence as well as local complications. All in all, VAMOS appears to have several advantages over current surgical strategies.

The Treatment of Incisional Hernia

BACKGROUND

A meta-analysis of studies from multiple countries has shown that the incidence of incisional hernia varies from 4% to 10% depending on the type of operation. No epidemiological surveys have been conducted so far. The worst possible complication of an incisional hernia if it is not treated surgically is incarceration. In this article, we present the main surgical methods of treating this condition. We also evaluate the available randomized and controlled trials (RCTs) in which open and laparoscopic techniques were compared and analyze the patients' quality of life.

METHODS

We selectively searched PubMed for relevant literature using the search terms "incisional hernia" and "randomized controlled trial." 9 RCTs were included in the analysis. The endpoints of the meta-analysis were the number of reoperations, complications, and recurrences. The observed events were studied statistically by correlation of two unpaired groups with a fixed-effects model and with a random-effects model. We analyzed the quality of life in our.

RESULTS

Open surgery and laparoscopic surgery for the repair of incisional hernias have similar rates of reoperation (odds ratio [OR] 0.419 favoring laparoscopy, 95% confidence interval [0.159; 1.100]; p = 0.077). The rates of surgical complications are also similar (OR 0.706; 95% CI [0.278; 1.783]; p = 0.461), although the data are highly heterogeneous, and the recurrence rates are comparable as well (OR 1.301; 95% CI [0,761; 2,225]; p = 0.336). In our own patient cohort in Würzburg, the quality of life was better in multiple categories one year after surgery.

CONCLUSION

The operative treatment of incisional hernia markedly improves patients' quality of life. The currently available evidence regarding the complication rates of open and laparoscopic surgical repair is highly heterogeneous, and further RCTs on this subject would therefore be desirable. Moreover, new study models are needed so that well-founded individualized treatment algorithms can be developed.

Implantation of a total abdominal mesh plastic ending up in multiple, lethal right heart injuries

We present the case of a 62-year old patient who had an elective surgery to implant a total abdominal plastic mesh due to massive herniation after prior lower body gun shots and deep wound infections. Twenty-four hours after the operation, the patient's condition deteriorated, ST-deviation occurred and the Troponin I test was positive. On admission, the patient needed moderate catecholamine therapy and echocardiography showed a pericardial effusion (>3 cm). Puncture of the effusion was impossible due to the plastic mesh and the patient was transferred to the operating room. A subxiphoidal pericardial incision was performed and 800 ml of fresh blood was drained. Despite this, the patient's condition worsened. A full sternotomy was performed, and intrathoracal cardiopulmonary resuscitation started. During examination of the pericardium and the heart, multiple plastic parts from the mesh fixation system were observed transdiaphragmally and were found to have penetrated the diaphragmal part of the right ventricle. In spite of maximum drug, respiratory and surgical therapy, a sufficient heart ejection fraction could not be achieved. Upon interdisciplinary consent, therapy was stopped after 60 min.

Prophylactic mesh placement in high-risk patients undergoing elective laparotomy: a systematic review

BACKGROUND

Incisional hernia is a significant complication in patients undergoing elective laparotomy. Its incidence is increased in patients with risk factors, such as obesity and chronic respiratory disease. The purpose of this pooled analysis was to evaluate the use of prophylactic mesh placement following laparotomy in high-risk patients.

METHODS

A systematic literature search of MEDLINE, Embase, Web of Science, and Cochrane database was conducted. Outcome measures were incidence of postoperative incisional hernia, seroma, and wound infection rates.

RESULTS

Five randomized, controlled trials (RCTs) and four comparative studies that met the inclusion criteria were identified. In total, 464 patients who underwent laparotomy closure with mesh placement and 755 patients who underwent conventional laparotomy closure were included. A reduced incidence of incisional hernia was observed when laparotomy was combined with prophylactic mesh placement in pooled analysis of RCTs (pooled odds ratio = 0.32; 95 % confidence interval = 0.12-0.83; P = 0.02) and comparative studies (pooled odds ratio = 0.11; 95 % confidence interval = 0.04-0.33; P < 0.001) respectively. No significant differences were observed in the incidence of seroma or wound infection following prophylactic mesh placement.

CONCLUSIONS

The results of this pooled analysis suggest a benefit to prophylactic mesh placement during laparotomy closure in high-risk patients with a significantly reduced incidence of incisional hernia without any significant differences in seroma formation and wound infection rates. Further studies must evaluate the incidence of mesh-specific complications, including foreign body sensation and chronic pain, before strong recommendations can be made.

Impact of the defect size, the mesh overlap and the fixation depth on ventral hernia repairs: a combined experimental and numerical approach

BACKGROUND

Ventral hernia repairs (VHRs) still exhibit clinical complications in terms of recurrence, pain, and discomfort. Factors such as surgical technique or mesh features are thought to be highly influent. The aim was to evaluate the impact of the defect size, the mesh overlap and the fixation depth on VHR using both physical and numerical models.

METHODS

The physical model was developed to mimic a passive abdominal wall. Healthy, damaged, and repaired configurations were evaluated using a spherical plunger. The associated numerical (Finite Elements) model was first loaded by a plunger for validation. A parametric study was then conducted with the numerical model loaded by a uniform pressure. Two defect sizes (3.5 × 5 cm and 8.25 × 12 cm elliptic shape), two overlaps (2 and 5 cm), and two fixation depths (peritoneum or muscle) were investigated for both passive and active abdominal walls.

RESULTS

With the physical model, the repaired configuration was 22 % stiffer than the damaged configuration. The statistical analysis of the parametric study showed that the defect size was the most influential parameter regarding the stress in the mesh, the bulging and the pull-out force at the fixation points. The overlap was influential in terms of stress in the mesh. The fixation depth was not influential. These trends increased with the abdominal wall activity.

CONCLUSION

Increase of the defect size and decrease of the overlap affected significantly the VHR mechanical performances. Such numerical models could help to better understand the behavior of the repaired abdominal wall and finally to reduce the clinical complications.

Long-term follow-up after incisional hernia repair: are there only benefits for symptomatic patients?

INTRODUCTION

Incisional hernias are among the most frequent complications in visceral surgery and are currently considered to be an indication for surgery in all cases, regardless of the patient's symptoms. However, it still remains unclear to what extent surgery actually results in improvement according to objective (e.g., less pain or dysesthesia) or subjective criteria (e.g., less discomfort or better cosmetic result). The purpose of this prospective study was to identify patients who derive objective and subjective benefit from surgical repair.

MATERIALS AND METHODS

This prospective study included patients who underwent open incisional hernia repair with mesh implantation from December 2006 to April 2009. Data were collected before and 18 months after surgery. Pain intensity was rated on the numerical analog scale (NAS) pre- and postoperatively. Patients were divided into oligosymptomatic (NAS 0-3) and symptomatic (NAS 4-10) groups based on their preoperative pain level, and the postoperative outcome of the two groups was compared by standardized questionnaire.

RESULTS

Ninety patients were prospectively enrolled, 45 (50 %) of each gender. Prior to surgery, 43 patients (47.8 %) were oligosymptomatic, and 47 (52.2 %) reported clinically relevant pain. Eighteen months after surgery, 7.5 % of the oligosymptomatic patients complained of clinically relevant pain; its rate remained unchanged. The symptomatic group showed a significant reduction in clinically relevant pain from 100 % to 14.0 %, (p < 0.001). The percentage of patients with clinically relevant dysesthesia was 12.5 % in the oligosymptomatic and 20.9 % in the symptomatic group 18 months postoperatively. The overall recurrence rate was 13.3 % after 18 months without difference in both groups. A reduction in discomfort in the surgical area was reported by 77.5 % of the oligosymptomatic and 79.1 % of the symptomatic patients.

CONCLUSIONS

Symptomatic patients definitely profit from surgical repair in the long-term course. However, the notable postoperative rate of clinically relevant pain and dysesthesia in oligosymptomatic patients and their high recurrence rate cast doubt on whether they really benefit from surgical repair. The remarkable degree of subjective satisfaction in oligosymptomatic patients should not be underestimated.

Gentamicin supplemented polyvinylidenfluoride mesh materials enhance tissue integration due to a transcriptionally reduced MMP-2 protein expression

Background

A beneficial effect of gentamicin supplemented mesh material on tissue integration is known. To further elucidate the interaction of collagen and MMP-2 in chronic foreign body reaction and to determine the significance of the MMP-2-specific regulatory element (RE-1) that is known to mediate 80% of the MMP-2 promoter activity, the spatial and temporal transcriptional regulation of the MMP-2 gene was analyzed at the cellular level.

Methods

A PVDF mesh material was surface modified by plasma-induced graft polymerization of acrylic acid (PVDF+PAAc). Three different gentamicin concentrations were bound to the provided active sites of the grafted mesh surfaces (2, 5 and 8 μg/mg). 75 male transgenic MMP-2/LacZ mice harbouring the LacZ reporter gene under control of MMP-2 regulatory sequence -1241/+423, excluding the RE-1 were randomized to five groups. Bilateral of the abdominal midline one of the five different meshes was implanted subcutaneously in each animal. MMP-2 gene transcription (anti-ß-galactosidase staining) and MMP-2 protein expression (anti-MMP-2 staining) were analyzed semiquantitatively by immunohistochemistry 7, 21 and 90 days after mesh implantation. The collagen type I/III ratio was analyzed by cross polarization microscopy to determine the quality of mesh integration.

Results

The perifilamentary ß-galactosidase expression as well as the collagen type I/III ratio increased up to the 90^th day for all mesh modifications, whereas no significant changes could be observed for MMP-2 protein expression between days 21 and 90. Both the 5 and 8 μg/mg gentamicin group showed significantly reduced levels of ß-galactosidase expression and MMP-2 positive stained cells when compared to the PVDF group on day 7, 21 and 90 respectively (5 μg/mg: p < 0.05 each; 8 μg/mg: p < 0.05 each). Though the type I/III collagen ratio increased over time for all mesh modifications significant differences to the PVDF mesh were only detected for the 8 μg/mg group at all 3 time points (p < 0.05 each).

Conclusions

Our current data indicate that lack of RE-1 is correlated with increased mesh induced MMP-2-gene expression for coated as well as for non-coated mesh materials. Gentamicin coating reduced MMP-2 transcription and protein expression. For the 8 μg/mg group this effect is associated with an increased type I/III collagen ratio. These findings suggest that gentamicin is beneficial for tissue integration after mesh implantation, which possibly is mediated via RE-1.

Evaluation of the safety and efficacy of MonoMax® suture material for abdominal wall closure after primary midline laparotomy-a controlled prospective multicentre trial: ISSAAC [NCT005725079]

Purpose

Different suture techniques and various suture materials are in use to close midline incisions after primary laparotomy. The ISSAAC study aimed to assess the safety and efficacy of the new ultra-long-term absorbable, elastic monofilament suture material MonoMax® for abdominal wall closure.

Methods

This is a single-arm, multicentre prospective study that included 150 patients undergoing a primary elective midline incision. The control group consists of 141 patients from the INSECT study who received MonoPlus® or PDS® for abdominal wall closure. The incidences of burst abdomen and wound infection until the day of discharge were defined as the primary composite endpoints. The rate of incisional hernias 1 year after surgery, the length of postoperative hospital stay and safety parameters served as secondary endpoints. The study has been registered under www.clinicaltrials.gov [NCT005725079].

Results

Eleven patients in the ISSAAC study [7.3%; 95% CI = (3.9; 13.1%)] experienced wound infection or burst abdomen until the day of discharge as compared to 16 [11.3%; 95% CI = (6.6; 17.8%)] patients in the INSECT control group (p = 0.31). The length of postoperative hospital stay was comparable in both study groups. One year after surgery, incisional hernias were observed in 21 ISSAAC patients (14.0%) in contrast to 30 hernias (21.3%) in the INSECT control group.

Conclusions

The ultra-long-term absorbable, elastic monofilament suture material MonoMax® is safe and efficient for abdominal wall closure.

Hernia recurrence as a problem of biology and collagen

Usually an abdominal wall hernia is regarded as a mechanical problem with a local defect which has to be closed by technical means. Despite the introduction of several therapeutic improvements, recurrent hernias still appear in 10-15%. Therefore, reasons for a recurrence are discussed in a more fundamental way. It is assumed that a failure mainly depends on the quality of the repair. Correspondingly, in principle, the close causal relationship between the technical component and its failure during time is reflected by an s-shaped outcome curve. In contrast, the configuration of the outcome curve changes markedly if a breakdown is caused by numerous components. Then, the superposition of all incidence curves inevitably leads to a linear decline of the outcome curve without any s-shaped deformation. Regarding outcome curves after hernia repair, the cumulative incidences for recurrences of both incisional and inguinal hernia show a linear rise over years. Considering the configuration of outcome curves of patients with hernia disease, it may therefore be insufficient to explain a recurrence just by a failing technical repair. Rather, biological reasons should be suspected, such as a defective wound healing with impaired scarring process. Recent molecular-biological findings provide increasing evidence of underlying biochemical alterations in patients with recurrent hernia. Until predicting markers to identify patients with an impaired wound healing are available and considering the formation of insufficient scar as the underlying disease, the consequences for every surgical repair should be a supplementary reinforcement with nonabsorbable alloplastic nets as flat meshes with an extensive overlap.

Laparoscopic versus open surgical techniques for ventral or incisional hernia repair

BACKGROUND

There are many different techniques currently in use for ventral and incisional hernia repair. Laparoscopic techniques have become more common in recent years, although the evidence is sparse.

OBJECTIVES

We compared laparoscopic with open repair in patients with (primary) ventral or incisional hernia.

SEARCH STRATEGY

We searched the following electronic databases: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, metaRegister of Controlled Trials. The last searches were conducted in July 2010. In addition, congress abstracts were searched by hand.

SELECTION CRITERIA

We selected randomised controlled studies (RCTs), which compared the two techniques in patients with ventral or incisional hernia. Studies were included irrespective of language, publication status, or sample size. We did not include quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

Two authors assessed trial quality and extracted data independently. Meta-analytic results are expressed as relative risks (RR) or weighted mean difference (WMD).

MAIN RESULTS

We included 10 RCTs with a total number of 880 patients suffering primarily from primary ventral or incisional hernia. No trials were identified on umbilical or parastomal hernia. The recurrence rate was not different between laparoscopic and open surgery (RR 1.22; 95% CI 0.62 to 2.38; I(2) = 0%), but patients were followed up for less than two years in half of the trials. Results on operative time were too heterogeneous to be pooled. The risk of intraoperative enterotomy was slightly higher in laparoscopic hernia repair (Peto OR 2.33; 95% CI 0.53 to 10.35), but this result stems from only 7 cases with bowel lesion (5 vs. 2). The most clear and consistent result was that laparoscopic surgery reduced the risk of wound infection (RR = 0.26; 95% CI 0.15 to 0.46; I(2)= 0%). Laparoscopic surgery shortened hospital stay significantly in 6 out of 9 trials, but again data were heterogeneous. Based on a small number of trials, it was not possible to detect any difference in pain intensity, both in the short- and long-term evaluation. Laparoscopic repair apparently led to much higher in-hospital costs.

AUTHORS' CONCLUSIONS

The short-term results of laparoscopic repair in ventral hernia are promising. In spite of the risks of adhesiolysis, the technique is safe. Nevertheless, long-term follow-up is needed in order to elucidate whether laparoscopic repair of ventral/incisional hernia is efficacious.

Biocompatibility of prosthetic meshes in abdominal surgery

Surgical meshes today represent a group of implants mainly used for hernia repair. Modern hernia surgery is no longer imaginable without the application of these special biomaterials leading to millions of implantations each year worldwide. Because clinical trials are insufficient to evaluate the distinct effects of modified mesh materials in regard to tissue biocompatibility and functionality, a basic understanding of the physicochemical properties of mesh materials, as well as the underlying cause for hernia formation, is essential for a rational selection of the most appropriate device. The most important properties of meshes were found to be the type of filament, tensile strength, and experimental data, which indicate that particularly the mesh's porosity is of outstanding importance.

Different methods of mesh fixation in open retromuscular incisional hernia repair: a comparative study in pigs

PURPOSE

Reinforcement of the abdominal wall with alloplastic mesh material in incisional hernia repair is well established. To avoid dislocation and migration of the prostheses, mesh fixation is recommended. However, there seems to be a correlation between postoperative pain and mesh fixation. Furthermore, it remains unclear whether mesh fixation is necessary at all.

METHODS

A retromuscular mesh implantation was performed in 36 pigs using a polypropylene-polyglecaprone 25 composite mesh (Ultrapro(®), 12 × 18 cm). In group 1, the mesh was fixed to the posterior rectus sheet with non absorbable single sutures (Prolene(®) 2-0), in group 2 fixation was with absorbable sutures (Vicryl(®) 2-0), in group 3 mesh fixation was with 5 ml fibrin sealant (Quixil(®)), and, as a control, there was no fixation in group 4. The abdominal wall was explanted on postoperative day 7, 14 and 56. Mesh size and position was measured, and pull-out force of the mesh was analysed mechanically by tensiometry. The ratio of collagen type I/III was analysed to determine the quality of mesh integration.

RESULTS

Neither mesh dislocation nor mesh migration was detected. Mesh size showed no significant differences, whether comparing time points or groups. No significant differences in the tensile strength of mesh integration were found when comparing the groups (group 1: 155 ± 17 mmHg; group 2: 175 ± 9 mmHg; group 3: 166 ± 24 mmHg; group 4: 172 ± 28 mmHg). Though the type I/III collagen ratio increased over time, no significant differences according to the type of fixation used were detected.

CONCLUSION

Mesh fixation in open incisional hernia repair with retromuscular mesh augmentation to avoid mesh dislocation or migration in the early postoperative period appears to be unnecessary.

Oligosymptomatic vs. symptomatic incisional hernias--who benefits from open repair?

INTRODUCTION

Incisional hernias are one of the most often complications in abdominal surgery and therefore present a significant surgical and socioeconomic problem. To date, incisional hernias are always an indication for surgery, regardless of the patient's symptoms. However, it remains unclear to what extent the surgery actually results in symptomatic improvement and whether a relevant risk of incarceration exists. The purpose of this study was to investigate the motivation that led to incisional hernia repairs and whether patients benefit from surgery with regard to pain and subjective criteria.

MATERIALS AND METHODS

This prospective study included patients who underwent open abdominal incisional hernia repair using mesh implantation. Data collection was done preoperatively and 6 months postoperatively. The intensity of pain was evaluated using the Numeric Analog Scale (NAS). Patients were divided according to their preoperative level of pain into oligosymptomatic (NAS 0-3) and symptomatic (NAS 4-10) groups, and the postoperative outcome of both groups was compared.

RESULTS

Ninety patients were prospectively enrolled: 45 males (50.0%) and 45 females (50.0%); 43 patients (47.8%) were oligosymptomatic preoperatively, while 47 patients (52.2%) reported relevant pain. The most frequent motivation for surgery named by the oligosymptomatic patients was fear of incarceration (79.1%), while the symptomatic patients mostly mentioned pain (76.6%). At 6 months postoperatively, significantly more oligosymptomatic patients complained of relevant pain (p < 0.001). In the symptomatic patient group, there was a significant reduction in relevant pain (p < 0.001). At that time, the level of relevant pain was comparable in both groups (33.3% versus 35.6%). Seven of 87 patients (8.0%) experienced recurrence within 6 months. Three patients with acute incarceration were treated with emergency repair (3.2%).

CONCLUSIONS

In patients with oligosymptomatic incisional hernias, fear of incarceration is the most frequent motivation for surgical treatment, even though the actual risk of incarceration seems to be rather low. If the incisional hernia causes relevant discomfort preoperatively, the surgery provides significant relief. In contrast, there is no improvement regarding pain in the oligosymptomatic patient group. This leads to the conclusion that, in the case of oligosymptomatic incisional hernias, the general indication for surgical revision should be viewed critically.

Impact of mesh positioning on foreign body reaction and collagenous ingrowth in a rabbit model of open incisional hernia repair

BACKGROUND

Incisional hernia remains as one of the most common surgical complications. Different mesh techniques are used in 75-80% of hernia repair. The aim of this study was to evaluate the dependence of mesh positioning and the type of mesh implanted on foreign body reaction and collagenous ingrowth.

MATERIALS AND METHODS

In 24 male Chinchilla rabbits, an incisional hernia repair was performed with mesh reinforcement either by sublay (n = 12) or by onlay technique (n = 12). In each group, two different types of mesh prosthesis were investigated: polypropylene (PP, Prolene) and polypropylene-polyglecaprone 25 composite (PP-PG, UltraPro). On postoperative day 60, the inflammatory and connective tissue formation was characterised by measuring the diameter of inner cellular infiltrate and outer fibrous capsule of the foreign body granuloma, and by verifying the collagen type I/III ratio. Furthermore, the expression of matrix metalloproteinase-2 (MMP-2) was analysed.

RESULTS

Microscopic investigation of the mesh/host-tissue interface showed typical formation of foreign body granuloma. The diameters of the inner part of the foreign body granuloma representing the amount of inflammatory cell infiltrate were significantly increased in the PP mesh compared to the PP-PG mesh, both in the sublay group (PP 13.1 +/- 1.21 microm vs. PP-PG 11.7 +/- 0.34 microm; P = 0.026) and in the onlay group (PP 13.1 +/- 1.24 microm vs. PP-PG 11.2 +/- 0.55 microm; P = 0.009). The diameter of the fibrous capsule as the outer ring of the granuloma was significantly increased when investigating the PP mesh in sublay position (29.5 +/- 1.12 microm) compared to the PP mesh in onlay position (27.9 +/- 0.73 microm) (P = 0.026). Investigating the quality of perifilamentary collagen deposition expressed as collagen type I/III ratio, the sublay group showed significantly elevated values compared to the onlay group (PP sublay 3.1 +/- 0.18 vs. PP onlay 2.4 +/- 0.41; P = 0.004) (PP-PG sublay 3.5 +/- 0.34 vs. PP-PG onlay 2.6 +/- 0.13; P = 0.002). The analysis of MMP-2 expression revealed no significant differences.

CONCLUSION

The beneficial results of mesh reinforcement in the sublay technique might be due to a superior quality of postoperative connective tissue formation. Mesh incorporation, irrespective of positioning, is favourable in low-weight, large, porous mesh material represented by a reduced inflammatory part of the foreign body granuloma.

Current practice of abdominal wall closure in elective surgery - Is there any consensus?

BACKGROUND

Development of incisional hernia after open abdominal surgery remains a major cause of post-operative morbidity. The aim of this study was to determine the current practice of surgeons in terms of access to and closure of the abdominal cavity in elective open surgery.

METHODS

Twelve surgical departments of the INSECT-Trial group documented the following variables for 50 consecutive patients undergoing abdominal surgery: fascial closure techniques, applied suture materials, application of subcutaneous sutures, subcutaneous drains, methods for skin closure. Descriptive analysis was performed and consensus of treatment variables was categorized into four levels: Strong consensus >95%, consensus 75-95%, overall agreement 50-75%, no consensus <50%.

RESULTS

157 out of 599 patients were eligible for analysis (85 (54%) midline, 54 (35%) transverse incisions). After midline incisions the fascia was closed continuously in 55 patients (65%), using slowly absorbable (n = 47, 55%), braided (n = 32, 38%) sutures with a strength of 1 (n = 48, 57%). In the transverse setting the fascia was closed continuously in 39 patients (72%) with slowly absorbable (n = 22, 41%) braided sutures (n = 27, 50%) with a strength of 1 (n = 30, 56%).

CONCLUSION

In the present evaluation midline incision was the most frequently applied access in elective open abdominal surgery. None of the treatments for abdominal wall closure (except skin closure in the midline group) is performed on a consensus level.

A historically controlled, single-arm, multi-centre, prospective trial to evaluate the safety and efficacy of MonoMax suture material for abdominal wall closure after primary midline laparotomy. ISSAAC-Trial [NCT005725079]

BACKGROUND

Several randomized controlled trials have compared different suture materials and techniques for abdominal wall closure with respect to the incidence of incisional hernias after midline laparotomy and shown that it remains, irrespective of the methods used, considerably high, ranging from 9% to 20%. The development of improved suture materials which would reduce postoperative complications may help to lower its frequency.

DESIGN

This is a historically controlled, single-arm, multi-centre, prospective trial to evaluate the safety of MonoMax suture material for abdominal wall closure in 150 patients with primary elective midline incisions. INSECT patients who underwent abdominal closure using Monoplus and PDS will serve as historical control group. The incidences of wound infections and of burst abdomen are defined as composite primary endpoints. Secondary endpoints are the frequency of incisional hernias within one year after operation and safety. To ensure adequate comparability in surgical performance and recruitment, the 4 largest centres of the INSECT-Trial will participate. After hospital discharge, the investigators will examine the enrolled patients again at 30 days and at 12 +/- 1 months after surgery.

CONCLUSION

This historically controlled, single-arm, multi-centre, prospective ISSAAC trial aims to assess whether the use of an ultra-long-lasting absorbable monofilament suture material is safe and efficient.

TRIAL REGISTRATION

NCT005725079.

Biomechanical analyses of overlap and mesh dislocation in an incisional hernia model in vitro

BACKGROUND

Incisional hernia repair is one of the most common surgical complications. Despite the introduction of mesh techniques of repair, recurrences are still prevalent. The aim of the current study was to evaluate the dependence of mesh dislocation on defect size, facial overlap, mesh-position, and orientation of the mesh in cases of anisotropic stretchability.

METHODS

An in vitro incisional hernia model was used, which consisted of a pressure chamber, an elastic silicone pad representing the peritoneal sac, and a silicone mat with bovine muscle tissue representing the abdominal wall. Intrinsic pressure (up to 200 mm Hg) was generated within the pressure chamber by continuous inflation with CO(2). A slit-like or flap-like defect was created in the silicone mat to simulate small or large hernia defects, respectively. The implanted mesh was arranged in both onlay and sublay configurations. A large pore polypropylene mesh with significant anisotropic stretchability was investigated, whereas overlaps of 2, 3, and 4 cm were applied.

RESULTS

Despite the application of pressures up to 200 mm Hg, no mesh ruptures occurred. In the slit-like defect model, the minimal overlap required to prevent dislocation at 200 mm Hg was 3 cm using the sublay technique provided that the mesh was positioned with its most stretchable axis parallel to the largest slit dehiscence. Perpendicular rotation of the mesh resulted in dislocation at 160 mm Hg, despite using an overlap of 3 cm. Mesh reinforcement showed less stability in both the onlay position and the flap-like defect.

CONCLUSION

An overlap of 3 cm is sufficient to prevent early mesh dislocation. Meshes with anisotropic stretchability should be orientated with the most stretchable axis in the direction of least overlap.

Mesh migration into the esophageal wall after mesh hiatoplasty: comparison of two alloplastic materials

BACKGROUND

Hiatal mesh implantation in the operative treatment of gastroesophageal reflux disease has become an increasing therapy option. Besides clinical results little is known about histological changes in the esophageal wall.

METHODS

Two different meshes [polypropylene (PP), Prolene; polypropylene-polyglecaprone 25 composite (PP-PG), Ultrapro] were placed on the diaphragm circular the esophagus of 20 female rabbits. After three months a swallow with iodine water-soluble contrast medium for functional analysis was performed. After the animals were sacrificed, histopathological evaluation of the foreign-body reaction, the localization of the mesh relating to the esophageal wall was analyzed.

RESULTS

Sixteen rabbits survived the complete observation period of three months. After three months distinctive mesh shrinkage was observed in all animals and meshes had lost up to 50% of their original size before implantation. We found a delayed passage of the fluid into the stomach in all operated animals. There was a significant increased diameter of the outer ring of granulomas in the PP group (76.5 +/- 8.0) compared to the PP-PG group (64 +/- 8.5; p = 0.002). However, we found a mesh migration into the esophageal wall in six out of seven animals (PP) and five out of nine animals (PP-PG), respectively.

CONCLUSION

Experimental data suggest that more knowledge is necessary to assess the optimal size, structure, and position of prosthetic materials for mesh hiatoplasty. The indication for mesh implantation in the hiatal region should be carried out very carefully.

Flank hernia and bulging after open nephrectomy: mesh repair by flank or median approach? Report of a novel technique

Flank incisions may be associated with flank hernias, which may be complicated with incarceration and strangulation. Furthermore, they may cause a significant limitation of the patient's quality of life. In the period 1997-2006 we performed 15 flank hernia repairs with a prosthetic mesh implantation. From 1997 to 2001 hernias were managed with a standardized mesh implantation through the initial flank incision (seven cases, flank group). Since 2001 we have adopted a novel operative approach in eight patients. Through a median laparotomy and following a transabdominally reduction of the hernia sac, a prosthetic polypropylene mesh [Prolene, Vypro or UltraPro, Ethicon Endo-Surgery (Europe) GmbH, Norderstedt, Germany] overlapping the midline was placed in a sublay technique (median group). The perioperative complication rate was comparable and they consisted mostly of postoperative seromas. A patient from the flank group developed a hernia recurrence two months after surgery. Thirteen patients participated in the annual follow-up for a total follow-up time of five years. In this period we observed only one additional case of hernia recurrence: a patient of the flank group presented with a 3 cm hernia recurrence at the proximal end of the previous operative incision. No recurrence was observed in the median group. As a result the novel technique for open repair of flank incisional hernias we present permits a remodelling of the abdominal wall and is associated with excellent postoperative results.

An alternative classification of incisional hernias enlisting morphology, body type and risk factors in the assessment of prognosis and tailoring of surgical technique

Incisional hernias occur in 5-10% of patients who have undergone laparotomy and are associated with a high morbidity and significant socioeconomic costs. Better understanding of the anatomy and improved methods for reinforcement of the abdominal wall with alloplastic meshes have reduced the recurrence rate to 1-10% depending on the type of hernia and the technique employed. A number of surgical repair techniques and mesh types are available. However, precise criteria for incorporating patient body type, risk factors for recurrence, hernia morphology, and the available biomaterials into planning of the surgical approach (open versus laparoscopic) have yet to be established. The elaboration of such criteria would require comparative evaluation of long-term results in a sufficiently large number of patients, e.g. in multicentre trials or meta-analyses of standardised data from different centres. Current classifications have the drawback that they fail to take account of prognostically relevant risk factors for recurrence and are not self-explanatory. The authors present a classification of incisional hernias that is self-explanatory and practicable in routine clinical practice. Based on the cornerstones of morphology (M), hernia size in cm (S), and risk factors for recurrence (RF), the scheme enables easy description and documentation of the hernia, and provides evidence for the indications and limitations of the main surgical repair techniques. Since randomised studies can scarcely be conducted on incisional hernias due to the numerous morphological variables, the classification presented here may offer an alternative means for comparative data analysis.

[Abdominal hernias resulting from abdominal flap harvest]

The anatomic characteristics of the anterior abdominal wall allow the harvesting of various types of flaps, some of them with considerable volume. These flaps are used mainly for reconstruction of the female breast, thoracic wall, and perineal or ilioinguinal region. Even though general donor site morbidity is low, hernias and "bulging" can occur due to the harvest of muscle and fascia, which leads to a weakening of the abdominal wall. Hernias and bulging appear mostly after harvest of classic flap types, which include removal of the rectus abdominis muscle. Further refinements of these flaps, i.e. microvascular flaps, in particular perforator flaps, lead to a marked reduction in donor site morbidity. In the following overview, the problem of abdominal wall weakening as a result of flap harvest is discussed and possible therapeutic options are elucidated.

Chirurgische Durchtrennung und Verschluss der Bauchdecke

Access to the abdominal cavity must be performed in such a way that surgical treatment procedures can be performed safely. For skin incision, scalpel and electrocautery are equivalent. Subcutaneous tissue and fascias must be divided by electrocautery to minimize blood loss. The best way to close the abdominal cavity is by an all layer, slowly absorbable, running suture with a suture: wound length ratio of at least 4:1. Closing the peritoneal layer is not necessary. Subcutaneous sutures and drains do not reduce the risk of wound complications. Staples should be used for closing the skin.

Versorgung von Bauchdeckendefekten einschließlich der Bauchwandrelaxation aus allgemeinchirurgischer Sicht

Abdominal wall defects that are amenable to direct fascial approximation are the indication for retromuscular mesh augmentation. Larger defects can be bridged with meshes used as abdominal wall substitution or with reconstructive flaps. Other options are indirect techniques to achieve primary preparation of the abdominal wall, either by mobilization of the abdominal wall muscles with the component separation method or by preoperative expansion of the abdominal cavity using a progressive pneumoperitoneum. Surgical repair of iatrogenic abdominal wall relaxations should combine plastic reconstruction with preperitoneal mesh implantation. Scientific evidence supporting any treatment option is weak, because few prospective, randomized trial data are available owing to the inhomogeneity of the patient population. Treatment of abdominal wall defects must therefore be proposed on an individual basis utilizing one or a combination of the techniques described.