Dirk Weyhe

Improving outcomes in hernia repair by the use of light meshes--a comparison of different implant constructions based on a critical appraisal of the literature.

BackgroundDespite convincing advantages offered by meshes, their use in hernia surgery remains controversial because of fears concerning the long-term effects of their implantation. To improve biocompatibility, a large variety of newly developed light meshes has been introduced to the market.This overview of the literature aimed to establish whether absolute material reduction (g per implanted mesh), use of absorbable components, and coating by inert materials are evidence-based ways to improve biocompatibility of meshes.MethodA review of the current English and German language literature on the outcome of groin und incisional hernia mesh repair was performed. Both basic research and clinical trials were used as sources of data. Meta-analyses and randomized controlled trials were given priority and were referred to whenever possible.ResultsOperative technique was an independent prognostic factor for the clinical outcome. Mesh construction and composition as characterized by pore size and filament structure appeared to be more important determinants of foreign body reaction after implantation than absolute material reduction of 1 g or more per implant. No data exist about an oncogenic effect of alloplastic materials in humans, but disturbed fertility in animal studies remains an issue of concern and should be further investigated.ConclusionsAccording to data from current randomized controlled trials and retrospective studies, light meshes seem to have some advantages with respect to postoperative pain and foreign body sensation. However, their use is associated with increased recurrence rates. Light meshes offer no advantages with respect to alleviating severe chronic groin pain. At the same time, experimental data reveal that material composition and mesh structure may significantly affect foreign body reaction.

Experimental comparison of monofile light and heavy polypropylene meshes : Less weight does not mean less biological response

BackgroundMesh implantation is a standard procedure in hernia repair. It provides low recurrence rate but increases complication rate due to foreign-body reaction induced by alloplastic materials in surrounding tissues. It is believed that biocompatibility of meshes may be improved by reducing their weight per meter squared (m2) and altering the implant structure.AimThe aim of this study was to evaluate the effect of weight and structure as determinants of mesh biocompatibility.MethodThirty-six Wistar rats were studied. In 12 animals, conventional polypropylene (heavy) meshes (HM) were implanted; in other 12, material-reduced (light) microporous polypropylene meshes (LM); and the remaining 12 served as a sham-operated control group. Meshes were explanted after 21 and 90 days (6 animals per group). All samples were examined by light and electron microscopies. Integration of meshes in surrounding tissue, inflammatory response, fibrotic reactions, and structural changes were recorded. Quantification of the inflammatory response was achieved by CD-68 marking of macrophages and counting their number per surface unit.ResultsAfter 21 days, there was no significant difference in thickness of surrounding connective tissue between meshes in all groups studied. After 90 days, thickness of connective tissue decreased in both groups, and fibrotic reaction in the mesh bed was significantly less in the HM group. Total amount of macrophages per millimeter squared (mm2) decreased with time in HM and LM samples but was significantly lower in the HM group on day 21 (43.5%) and day 90 (46.7%).ConclusionThis study found worse biocompatibility of LM compared with HM. Thus, the amount of implanted mesh was not the main determinant of biocompatibility (expressed as successful incorporation and diminished foreign-body reaction) but the size of the pores.

Role of endogenous glucocorticoid metabolism in human acute pancreatitis

Objective:This study aimed to observe how levels of total cortisol, calculated free cortisol, corticosteroid-binding globulin, and adrenocorticotropic hormone change during the early course of human acute pancreatitis and to describe how these changes affect the development of pancreatic necrosis. Design and Patients:In a total of 109 consecutive patients with acute pancreatitis (74 with edematous pancreatitis, 35 with necrotizing pancreatitis), serial daily blood monitoring of total and free cortisol, adrenocorticotropic hormone, and corticosteroid-binding globulin was done after hospital admission, up to day 6 after the onset of pain; 30 healthy individuals served as controls. Measurements:Corticosteroid-binding globulin and total cortisol were measured by immunoassays, and free cortisol was calculated according to Coolens et al. The adrenocorticotropic hormone was measured with an enzyme-linked immunoassay. Results:Initially, highly elevated levels of calculated free cortisol (median, 86.2 ng/mL; quartile ranges, 50.6–106.7 ng/mL) and total cortisol (41.2 &mgr;g/dL, 30.4–51.1 &mgr;g/dL) and depressed levels of adrenocorticotropic hormone (0.2 pg/mL, 0.1–2.0 pg/mL) and corticosteroid-binding globulin (30.6 &mgr;g/mL, 24.1–35.5 &mgr;g/mL) were observed. Further, daily measurements revealed increasing adrenocorticotropic hormone levels, whereas cortisol levels decreased. Conclusions:Although an increase in adrenocorticotropic hormone levels is suggested to increase corresponding cortisol levels, cortisol levels decreased during the development of necrotizing acute pancreatitis. This phenomenon, along with the continuously decreasing corticosteroid-binding globulin levels, brings up the hypothesis of a relative adrenal insufficiency, which favors acinar cell apoptosis and hence may trigger the development of necrosis in the initial vulnerable phase of acute pancreatitis.

Bacteribilia after preoperative bile duct stenting: a prospective study.

Study Design A prospective analysis of intraoperative bile duct cultures in patients undergoing surgery for both, malignant or benign periampullary diseases at the Department of Surgery, St Josef Hospital, Bochum, Germany, during a period of 18 months, between January 2004 and June 2005. Goals The goals of the presented study were to investigate the effects of preoperative bile duct stenting on intraoperative bile duct cultures and postoperative outcome in patients undergoing pancreatic surgery. Background In pancreatic surgery, bile duct stenting is often aimed at improving postoperative outcome. As implantation of xenograft material in the main bile duct facilitates bacterial contamination and cholangitis, a critical evaluation of stenting is mandatory. Study In all patients with a hepaticojejunostomy (n=80), a bile duct culture was collected during the operation. All patients received antibiotic prophylaxis perioperatively and a retrograde flushing of bile ducts with warm saline after bile duct resection. Fifty-one percent (41/80) patients had biliary drainage before surgery, whereas 49% (39/80) were operated without preoperative draining procedures. Results After bile duct stenting, 98% of patients had a positive bile culture, whereas only 21% of infected bile was seen in patients without drainage (P<0.001). Despite infected bile, only 2% stented patients developed acute cholangitis postoperatively, versus 13% patients in the group without stent (P=0.231). After stenting, major complications occurred in 12%, versus 8% in patients without stent (P=0.817). Conclusions Preoperative biliary drainage leads to an almost 100% bacterial contamination of bile ducts. With hospital-adjusted antibiotic prophylaxis and retrograde flushing of bile ducts, the postoperative rate of acute cholangitis and morbidity is not elevated. A critical evaluation of benefits from preoperative biliary drainage for each patient is necessary.

IN VITRO COMPARISON OF THREE DIFFERENT MESH CONSTRUCTIONS

Background:  Material amount and pore size have been recently discussed as probable important determinants of biocompatibility of mesh implants used in hernia repair. This study aimed to find out whether other constructional parameters affect the extent of early foreign body reaction in vitro.

Fecal incontinence: an up-to-date critical overview of surgical treatment options

BackgroundSurgery is the last resort for patients suffering from severe fecal incontinence. The armamentarium of surgical options for this condition has increased impressively during the last decade. Nevertheless, this fact seems to make neither patients nor surgeons feel more comfortable. Treatment of fecal incontinence still remains a challenge to modern medicine due to many specific sides of this problem.AimsThis article gives an up-to-date overview of existing operative treatment options.MethodsAn unbiased review of relevant literature was performed to assess the role of all methods of surgical treatment for fecal incontinence available nowadays.ResultsRecent studies have shown poor late results after primary sphincter repair and low predictive value for most preoperative diagnostic tests. New surgical options such as artificial devices and electrically stimulated muscle transpositions are doomed by low success rates and unacceptably frequent complications. That is why current attention has focused on non- or minimally invasive therapies such as sacral nerve stimulation and temperature-controlled radio-frequency energy delivery to the anal canal. However, all these innovative techniques remain experimental till enough high-evidence data are gathered for their objective evaluation.ConclusionCareful and detailed preoperative assessment to exactly determine the etiology of incontinence and individual approach remain the cornerstones of surgical treatment of fecal incontinence nowadays.

The role of TGF-β1 as a determinant of foreign body reaction to alloplastic materials in rat fibroblast cultures: comparison of different commercially available polypropylene meshes for hernia repair

BACKGROUND Animal experiments on hernia repair demonstrated better biocompatibility of light-weight polypropylene meshes. However, implanted medical devices trigger a variety of adverse tissue responses, such as inflammation, fibrosis, infection and thrombosis, but the mechanisms involved in such responses remain largely unknown. This study aimed to determine the effect of transforming growth factor beta1 (TGF-beta1) on host tolerance by quantification of foreign body reaction in cultured fibroblasts depending on the amount and composition of implanted material used for hernia repair. MATERIALS AND METHODS An NRK-49F fibroblast culture was incubated in the presence of 4 commercially available meshes approved for hernia repair. A mesh-free cell suspension served as a control group, in which the influence of TGF-beta1 on fibroblasts was evaluated. Levels of TGF-beta1 in the supernatant were dynamically measured in a time interval of 6 to 96 h and cell proliferation rates were assessed colorimetrically using MTT test. RESULTS A dose-dependent suppression of fibroblasts proliferation by TGF-beta1 was observed. All meshes suppressed the secretion of TGF-beta1 and conversely increased significantly cell proliferation in comparison to the control group (p<0.01) in the first 24 to 48 h of incubation. That effect was more pronounced in meshes partially containing absorbable material when compared to samples of pure polypropylene meshes (p<0.05) and to the control group (p<0.001). CONCLUSION Our experiment revealed that early biological reaction of connective tissue cells towards polypropylene meshes and their variants depended much more on the composition and type of the material than on its absolute amount. The assumption that material weight reduction alone might affect the foreign body reaction of mesh implants could not be confirmed by our in vitro study.

Redo-Surgery following Curative Resection of Pancreatic Carcinoma: The Difference between True and Suspected Recurrence

Background: Improving results have led to an extension of indications for re-resection of recurrent pancreatic carcinoma. Methods: Among 410 patients who received surgery for histologically proven pancreatic cancer, 17 underwent re-resection for a suspected local recurrence and were evaluated for overall survival, clinicopathological and perioperative data. Results: At the initial operation, resection was curative (R0/R1) in all 17 patients. Indication for re-resection was a suspected or proven recurrence of pancreatic cancer in all patients. Re-resection was possible in 5 patients. The remaining patients received a redo of the pancreaticojejunostomy or bilioenteric anastomosis (n = 2), exploration with biopsy (n = 4), and a palliative bypass (n = 6). Perioperative mortality was 6%. Median overall survival was 25 months (range 10–152 months) and 7 months following re-resection (5–29 months). In 5 of 17 patients, histology showed chronic pancreatitis (n = 4) or a benign stricture at the hepaticojejunostomy (n = 1), whereas all other patients had histologically proven recurrence. Re-resection or redo of the anastomosis was possible in 5 of 5 patients with chronic pancreatitis but only in 2 of 12 patients with true recurrence (p = 0.003). Conclusions: Curative reoperation for recurrent pancreatic carcinoma is rarely feasible. Due to the potential for chronic pancreatitis or benign strictures as an underlying pathology, operable patients should be explored.

TME quality in rectal cancer surgery

BackgroundThe concept of total mesorectal excision has revolutionised rectal cancer surgery. TME reduces the rate of local recurrence and tumour associated mortality. However, in clinical trials only 50% of the removed rectal tumours have an optimal TME quality. Patients: During a period of 36 months we performed 103 rectal resections. The majority of patients (76%; 78/103) received an anterior resection. The remaining patients underwent either abdominoperineal resection (16%; 17/103), Hartmanns procedure (6%; 6/103) or colectomy (2%; 2/103).ResultsIn 90% (93/103) TME quality control could be performed. 99% (92/93) of resected tumours had optimal TME quality. In 1% (1/93) the mesorectum was nearly complete. None of the removed tumours had an incomplete mesorectum. In 98% (91/93) the circumferential resection margin was negative. Major surgical complications occurred in 17% (18/103). 5% (4/78) of patients with anterior resection had anastomotic leakage. 17% (17/103) developed wound infections. Mortality after elective surgery was 4% (4/95).ConclusionOptimal TME quality results can be achieved in all stages of rectal cancer with a rate of morbidity and mortality comparable to the results from the literature. Future studies should evaluate outcome and local recurrence in accordance to the degree of TME quality.

The effect of synacthen on acute necrotizing pancreatitis in rats.

Objectives: This study investigates the hypothesis that an adrenocorticotropic hormone-analog therapy may ameliorate relative adrenal insufficiency in the early phase of acute necrotizing pancreatitis (NP) by boosting endogenous glucocorticoid production. Methods: Forty Wistar rats with taurocholate-induced NP were divided into 5 groups: the first group received low-dose Synacthen (0.5 mg/kg); the second, high-dose Synacthen (5mg/kg); the third,low-dose cortisol (10 mg/kg); the fourth, high-dose cortisol (100 mg/kg); and the fifth, the control group, received no treatment. All animals were killed after 6 hours: concentrations of plasma corticosterone, interleukin 1 (IL-1), IL-6, IL-10, tumor necrosis factor &agr;, amylase, and lipase in ascites, myeloperoxidase activity in the pancreas, and a histological score were evaluated. Results: Corticosterone increased neither in the low-dose nor in the high-dose Synacthen group. Synacthen did not improve the early course of NP in terms of laboratory and histological results. A reduction of pancreatic necrosis and inflammation was observed in the low-dose cortisol group. Conclusions: Endogenous glucocorticoid release seemed to be at its maximum during the early stage of NP and could not be further increased by Synacthen. Low-dose exogenous cortisol ameliorated the disease. These findings support the existence of relative adrenal insufficiency in the early phase of acute NP.