Titanium coated light weight polypropylene meshes in inguinal hernia repair: A prospective study

Titanium coated light weight polypropylene meshes in inguinal hernia repair: A prospective study Johannes Schmidt a, Mike Ralf Langenbach b, Hubert Zirngibl c a Department of Surgery, Krankenhaus Landshut-Achdorf, Landshut, Germany b Department of Surgery, Helios St. Elisabeth Klinik, Oberhausen, Germany c Department of Surgery, University Witten-Herdecke, Wuppertal, Germany Abstract * Author for correspondence: Johannes Schmidt, email: johannes.schmidt@kh-landshut-achdorf.de Received 7 May 2010; Accepted 10 Nov 2010; Available Online 14 Apr 2011 Introduction: The use of biocompatible material in humans is unavoidable in many ways. Latest studies revealed the importance of weight reduced meshes in hernia surgery. Titanium is a safe material for implants studied over many years. A prospective trial was therefore projected to document the qualities of titanium coated polypropylene meshes. Experimental: 117 consecutive patients with primary or / and recurrent inguinal hernia were included and treated either by TAPP or Lichtenstein repair. A cohort of 20 male patients with primary inguinal hernia undergoing TAPP was compared retrospectively to the results from a prospective randomized trial projected earlier, where three different types of mesh had been tested: a monofile heavy weight polypropylene, a smooth heavy weight polypropylene and a polyglactin/polypropylene compound-mesh. Complications, pain development, inability to work, physical conditions, testicular volume and blood circulation were documented. SF 36 evaluation score was used. Results and Discussion: Side effects of titanium coated meshes did not differ significantly from those of actually used light-weight meshes. Seroma formation was similar as noted with polypropylene alone. Pain development was lesser in the titanium group, the same as reduction in everyday life activities. Urological affections were similar as with low weight polypropylene and compound meshes. Patients with TAPP present lesser general impairment than patients with Lichtenstein repair. Conclusions: The titanium coated mesh offers more overall comfort to patients with inguinal hernia repair than low-weight and compound polypropylene meshes. Hernia surgery should abstain from a general use of high weight polypropylene meshes. Keywords: Titanium coated mesh; Inguinal hernia; Laparoscopy 1. Introduction Implants of biomaterial usually cause inflammatory reactions in humans to a certain extent. Specially polypropylene happens to induce a heavy foreign body reaction although being compatible to the human organism. Focussing on these aspects meshes with less unresorbable material were tested and the reduction of postoperative local affections was achieved [1]. Compound-meshes made of two components (resorbable polyglactine, unresorbable polypropylene) and reduced in weight presented extremely good results what led to a market leading position for this type of mesh from 2000 to 2005 [2,3]. Many surgeons on the other hand experienced long term problems with light-weight and compound meshes such as pain sensation [4], shrinkage [5], migration [6], infection [7], and recurrent hernia [8]. Lichtenstein repair, endoscopic transabdominal preperitoneal (TAPP) and the totally extraperitoneal (TEP) polypropylene mesh implants are by now well established procedures for inguinal hernia surgery. Clinical studies have demonstrated, that endoscopic hernia repair may be as safe and effective with the same results as traditional surgical therapy [9-17]. In these procedures mainly polypropylene meshes are used for repair. Regarding postoperative complications with meshes and in absence of clinically secured proofs for or against a malignancy inducing potential of biological materials in humans a discussion about the "ideal mesh is been brought up continuously [18-20]. Polypropylene mesh may cause an extensive but intended inflammatory reaction forming a scar disk that reduces the abdominal wall movement [18-21]. Titanium implants on the other hand are very stable and reduce these local alterations in soft tissue [22,23]. A variant of a titanium coated low weight polypropylene mesh with less rigidity should therefore reduce postoperative affection and give even better results as low weight polypropylene and compound meshes [24]. Titanium's 64

biocompatibility may be associated with its fast oxidizing capacity, which can inhibit its binding with proteins. Therefore a prospective, non-randomised study was started to measure the comfort of an ultra low weight titanium coated polypropylene mesh in humans being operated for groin hernia. In a second setting a cohort out of these patients should be compared to the results from an earlier conducted prospective randomised study from our team, where three different meshes were tested for comfort and postoperative affections after endoscopic hernia repair in males [25]. 2. Experimental From September 2007 to September 2008 a total of 161 patients (139 male and 22 female) undergoing repair for primary or recurrent inguinal hernia entered the study. Average age was 63.5 + 9.1 years (male 62.7 and female 67.1). All patients were passed through an algorithm and were then scheduled for operation. Patients aged between 20 and 40 were selected for Shouldice repair, patients aged 40 and above or presenting with recurrent hernia were selected for mesh repair. In order to retrieve a significant cohort to be comparable to the patients of our prior study, the first 20 male patients aged 40 and above with primary groin hernia were selected for endoscopic hernia repair (TAPP). In all patients with mesh repair a new monofile ultra low weight titanium coated polypropylene mesh (PP Ti, monofilament, coating thickness 30 nm, mesh thickness 0.2 mm, weight 16 g/m 2 ) was used (see Figures 6 and 7). In the study performed earlier patients had been treated with either a monofile heavy weight (108 g/m 2 ) rigid polypropylene or with a smooth heavy weight multifile variant (116 g/m 2 ) of polypropylene or with a compound-mesh made of polyglactin (PG) and polypropylene (PP) (PG 54.6 g/m 2, PP 26.8 g/m 2 ). On the day prior to the operation a detailed physical investigation with determination of the blood routine and a doppler-ultrasound investigation of the testicular vessels (testicular artery, plexus pampiniformis) was performed. The testicle volume was likewise documented by means of ultrasound. At the 1 st and 3 rd postoperative day as well as after the 1 st, 2 nd 4 th, 8 th and 12 th postoperative week based on questionnaires pain development (visual scales) impairment of the sexual life and return to working life (duration of the inability to work) were measured. Additionally on the 3 rd postoperative day the blood circulation of the testicles was again documented by means of doppler-ultrasound and a congestion of the plexus pampiniformis was excluded. Testicular volume was again measured by ultrasonography. The physical conditions were checked in the 2 nd, 4 th, 8 th and 12 th postoperative week by using the German SF-36 Health Survey Test. This test is an instrument to evaluate the influence on quality of life for therapies by measuring four components: general physical conditions, social relations, psychological conditions and functional competence. Furthermore postoperative complications were documented. Lichtenstein procedure was performed after cutting the hernial sac and tailoring the mesh according to the specific anatomical requirements. Sutures were performed with 2x0 Prolene (Ethicon). Wound drainages were not used. Pneumoperitoneum was built up with CO 2 at 15 mm Hg. A 10 mm trocar was placed within the umbilicus and two 10 mm trocars were placed laterally. The hernia was identified and the peritoneum was prepared. The hernia sac was pulled back into the abdomen and the anatomical structures of the spermatic trunc were separated from the peritoneum. The mesh was positioned directly on the transverse fascia and fixed cranially, medially and laterally to the epigastric vessels with a hernia stapler. The peritoneum was closed with the stapler too. Exclusion criteria were: age between 20 and 40 years, bilateral hernia, BMI > 35, peripheral arterial disease worse than clinical stage IIb, scrotal hernia, neurological affections or paresthesia of the genital region or the lateral region of the proximal lower extremity, polyneuropathy, disturbance of the testicular blood circulation with testicular atrophy, therapy with anticoagulative drugs, chronic back pain, hydrocele, epididymitis, funiculitis or acute incarceration. The study was referred to and checked by the local statistician of the University of Witten- Herdecke. Data are expressed in means (M SEM). To prove statistical relevance Students t-test with an alpha-mistake of p<0.05 was used. The analysis of SF-36 Health Survey was done with an SAS supported, computerized program. The scales of SF-36 had to be transformed in values of numbers between 0 and 100 to make them comparable in each group and the different groups of patients. 65

Table 1. Lichtenstein Shouldice TAPP Primary hernia 76 44 22 Recurrent hernia 14 0 5 Total 90 44 27 The meshes used in the preceding study were: PP heavy: Synthetic, colorless mesh made by a monofil polypropylene thread (Ethicon) with a thickness of 0.9 mm and a weight of 108 g/m 2 (DIN 53 884). PP light: Synthetic, colorless mesh made by multifile polypropylene threads (Serag-Wiessner, SN 0.4) with a thickness of 0.5 mm and a weight of 116 g/m 2 (DIN 53 884). PP / PG: Synthetic, colored, made by multifile polypropylene and polyglactine threads (Ethicon) with a thickness of 0.9 mm and a weight of 54.6 g/m 2 (PP) / 26.8 g/m 2 (PG) (DIN 53884). 3. Results 139 male and 22 female patients entered the study. We found 122 lateral, 31 medial and 10 combined inguinal hernias. 19 patients presented a recurrent hernia. 3 additional femoral hernias were found intraoperatively. 44 patients were selected for Shouldice repair, the remaining 117 patients were treated by titanium mesh implant. Within this group were 108 male and 9 female patients. Age for male patients was 66.3 + 11.2, for female patients it was 62.7 + 13.6 years. The first 20 consecutive patients were selected for TAPP repair. In this cohort mean age was 63.4 + 3.8 years. In the TAPP sub-group we found 3 recurrent hernias (20 %) and one additional femoral hernia on the treated side. In the Lichtenstein group we had 14 patients with recurrences (15.6 %). 90 patients were treated by Lichtenstein repair (including all 9 female patients) and 27 with TAPP (see Table 1). Incidence of COPD, hypercholesterinemia and -lipidemia, diabetes, arterial hypertony and coronary heart disease was comparable in all sub-groups. The size of the hernia was measured during the operation and the surface was calculated. In all collectives the surface was determined between 3 and 16 cm 2. Operation time was different in the four groups. Lichtenstein repair in primary hernia could be performed faster than TAPP but took longer in recurrent hernia. In the TAPP group there was almost no difference between primary and recurrent hernia (see Table 2). In all collectives patients spent nearly the same time in hospital. Lichtenstein patients with primary hernia were in 3.7 days, with recurrent hernia 3.6 days. Patients with TAPP and primary hernia stayed 3.4 days, with recurrent hernia 3.6 days (see Table 2). 19 male patients had a reduction of the Doppler signals in the testicular vessels at the hernia site at preoperative check. After surgical therapy this reduction was gone in 16 and improved in 3 patients. There were no postoperative atrophies of the testicles found. In the Lichtenstein group the average inability to work was 24.6 days for primary and 25.3 days for recurrent hernia (n.s.) in the TAPP group return to normal activity was possible after 19.5 days for primary and 18.9 days for recurrent hernia (n.s.). Difference between Lichtenstein and TAPP was significant (p <0.05) for return to normal activities (see Table 2). In the sub-groups nearly the same number of complications occurred in the form of scrotal and / or abdominal wall hematoma, testicular contact pain at the operated site and seroma formation on the 1 st and 3 rd postoperative days (see Table 3). In short term follow-up we Table 2 Lichtenstein TAPP primary recurrent primary recurrent n 76 14 22 5 operation time 42.6 min 62.7 min 51.5 min 53.4 min hospital stay 3.7 days 3.6 days 3.4 days 3.6 days return to work 24.6 days 25.3 days 19.5 days 18.9 days 66

Table 3 Lichtenstein TAPP primary recurrent primary recurrent n 76 14 22 5 male 69 12 22 5 female 7 2 / / VAS pain day 1 2.5 2.6 2.7 2.8 day 3 1.3 1.4 1.5 1.8 day 7 0.9 0.9 1.0 1.0 pain killers day 1 16 2 2 1 day 3 8 1 1 / day 7 4 1 / / pain during mobilization day 1 28 3 4 1 day 3 8 2 2 1 day 7 4 2 1 / abdominal wall hematoma day 1 3 1 2 / day 3 3 1 2 / day 7 / 1 2 / scrotal hematoma day 1 4 1 1 1 day 3 3 1 2 1 day 7 3 1 3 / testicular pain day 1 4 2 1 1 day 3 3 / 1 1 day 7 3 / 2 / detected 1 recurrent hernia in the TAPP group (3.7 %) and 2 recurrences in the Lichtenstein group (2.2 %). 3 patients could not be contacted for final examination and were listed as drop-outs. Lethality was 0%. Pain development was similar in the four groups. The administration of pain killers (Ibuprofene, Metamizole) was significantly higher in the Lichtenstein group (11 % vs. 20 %, p<0.05) Reduction in analgesics was seen parallel to the reduction in VAS values on days 3 and 7. Pain during mobilization was significantly higher in the Lichtenstein group (34 % vs. 18 %, p<0.05) whereas patients with recurrent hernia did not present more problems than patients with primary hernia. Formation of abdominal wall hematoma, scrotal hematoma and testicular pain in male patients did not differ significantly between the four groups (see Table 3). Pain scales in week 2, 4 and 12 did not show differences between the Lichtenstein and the TAPP groups, 3 months after the operation pain was resolved in 98 % of the patients. Dysuria, specially discomfort at urination, was noted more in the Lichtenstein group, but there was no statistical difference. Seroma formation was similar in the Lichtenstein and the TAPP group. Lichtenstein patients with recurrent hernia had higher risk of seroma than with primary hernia (14 % vs. 8 %) not 67

Table 4 Lichtenstein TAPP primary recurrent primary recurrent n 76 14 22 5 male 69 12 22 5 female 7 2 / / VAS pain week 2 0.8 0.8 0.8 0.7 week 4 0.6 0.7 0.7 0.6 week 12 0.1 / 0.2 0.1 dysuria week 2 10 2 / 1 week 4 4 1 / 1 week 12 3 / / / seroma week 2 6 2 1 1 week 4 2 1 1 1 week 12 / / / / pain with ejaculation week 2 3 1 1 / week 4 1 / 1 / week 12 / / / / return to normal week 2 30 5 10 2 week 4 50 7 16 4 week 12 71 11 21 4 reaching statistic difference. From the first postoperative week pain with ejaculation was noted in male patients. Differences between the four groups were not significant. Analyzing impairment of sexual life with pain in the hypogastric region, painful touch of the testicles and painful ejaculation no differences were found between the two groups (see Table 4). Results of the questionnaires of SF-36 concerning the general physical condition and the pain development showed significant differences between the Lichtenstein and the TAPP group. (see Figures 1 and 2). Before operation we found nearly the same figures in both collectives concerning the general physical conditions and sensations of pain (average figures for a normal German population by SF-36: general physical condition with patients between 61 and 70 years: 74.79±22.29; pain sensation in patients between 61 and 70 years: 72.71±33.96). In the 4 th and 8 th postoperative week we found significant differences in the collectives concerning these aspects (see Figure 1). The physical fitness was better in the TAPP group, recurrent hernia did not influence these results. Lichtenstein patients complained about a stronger pain sensation in family activities and at home as well as their sexual life was concerned in comparison to TAPP patients. This difference was significant at week 8 where Lichtenstein patients had not reached the preoperative SF-36 values and TAPP patients had already equaled them (see Figure 2). The postoperative impairment of everyday activities (taking a book from the shelf, bearing a bucket of water, washing the body, picking up a small gadget from the ground, sitting up in bed, dressing, running fast) in the 1 st, 4 th and 12 th postoperative week was registered stronger in patients with Lichtenstein repair. Our team has already tested three different meshes in an earlier, prospective randomized setting in 60 male TAPP patients (see Table 5). We constructed a sub-group out of the first male patients entering the actual study for TAPP in primary hernia. Therefore all patients with recurrent 68

Development of general physical condition according to SF-36 100 90 transformed figures by SF-36 80 70 60 50 40 30 20 10 TAPP primary TAPP recurrent Lichtenstein primary Lichtenstein recurrent 0 preoperative week 4 week 8 week 12 Figure 1. Pain development according to SF-36 (higher score = less pain) 80 transformed figures according to SF-36 70 60 50 40 30 20 10 TAPP primary TAPP recurrent Lichtenstein primary Lichtenstein recurrent 0 preoperative week 4 week 8 week 12 Figure 2. Table 5 material PP heavy PP light PP / PG PP / Ti filament monofilament multifilament multifilament monofilament weight 108 g/m2 116 g/m2 26.8/54.6 g/m2 16 g/m2thickness 0.9 mm 0.5 mm 0.9 mm 0.2 mm longitudinal traction 597 N 595 N 387 N > 50 N transverse traction 767 N 477 N 63 N > 40 N 69

Pain development after TAPP for primary hernia in male patients (VAS) 4 3,5 3 VAS 2,5 2 1,5 PP heavy PP light PP / PG PP / Ti 1 0,5 0 day1 day 3 week 1 week 4 week 8 week 12 Figure 3. hernia (n = 5) where withdrawn from this cohort. Mean age in these patients was 63.4 + 3.8 years, in the other groups it was comparable with 64.5 + 7.4 years. Incidence for COPD, cardiovascular disease, diabetes and arterial hypertony was comparable. Therefore we felt secure to perform a retrospective (historical) statistical evaluation. In male TAPP patients VAS for postoperative pain was lesser for PP Ti throughout day 1 (p < 0.05) but was not different between light weight meshes from day 3 on. Patients with heavy weight meshes experienced significantly more pain than patients with light weight meshes (see Figure 3). Development of physical condition after surgery was best for PP Ti patients whereas we only found a statistical difference at week 4 to PP light. Differences between PP / PG and PP Ti did not reach statitistical difference at any time. General physical condition 12 weeks after surgery was higher than preoperative values for all tested meshes (see Figure 4). Evaluation of pain after transforming SF-36 values for weeks 4 to 12 showed statistical differences (p < 0.05) between low weight and high weight meshes, but differences between the 3 light weight meshes did not reach statistic relevance. Nevertheless patients with PP Ti presented tendency to best outcome (see Figure 5). Development of general physical condition after TAPP for primary hernia in male patients according to SF-36 100 transformed figures according to SF-36 90 80 70 60 50 40 30 20 10 PP heavy PP light PP / PG PP / Ti 0 preoperative week 4 week 8 week 12 Figure 4. 70

Development of pain after TAPP for primary hernia in male patients (higher score = less pain) 90 transformed figures according to SF-36 80 70 60 50 40 30 20 10 PP heavy PP light PP / PG PP / Ti 0 preoperative week 4 week 8 week 12 Figure 5. 4. Discussion Titanium and its alloys are used all over the world in surgery. The favorable characteristics that make this material recommendable for implants are corrosion resistance and high biocompatibility. Concerning hernia repair, a mesh modification has been developed using titanium layering of a polypropylene mesh implant, which is said to lead to an improved biocompatibility compared to commercially available mesh materials [24]. First presentation of these titanium coated meshes was in 2001. A survey of 22 German surgical departments was published in 2004. During a period of 8.3 months each institution gained experience with a median of 83 titanised polypropylene meshes in the treatment of inguinal hernia using the TAPP technique. Mesh related major complications were not observed and none of the patients required analgesic medication. Postoperatively 89 % of the patients were highly satisfied with the results. In this study two different types of titanium coated mesh (35 g/m 2 and in 16 g/m 2 ) were used [24]. These positive clinical reports are not consistent with results from an animal model presented lately [26]. Two different mesh structures were studied in Sprague-Dawley rats: a titanium-coated monofilamentous, large porous, and light weight polypropylene mesh coated with titanium was compared to a polypropylene mesh manufactured with a similar structure and amount of material serving as control. Both mesh modifications showed an overall good biocompatibility. Tissue response for both meshes was characterized by a moderate inflammatory tissue reaction limited to the perifilamentary region typically seen in low weight, large porous, and monofilamentous mesh structures. Titanium coating did not improve biocompatibility when compared to the pure polypropylene mesh structure. The results of the study presented here are consistent with both findings. The differences between PP Ti and PP / PG meshes are hardly there. The local reaction of PP Ti is lesser when compared to PP / PG compound meshes, and tissue response of PP / PG compound meshes is lesser when compared to low weight PP meshes (see Figure 4). These differences are clearly present between week 4 and 8 but disappear 3 months after the operation. On the other hand pain sensation is only different during the early postoperative period turning to nearly 0 after the third postoperative day (see FIgure 3). So we definitely have a small difference in pain development and clinical outcome on one side and a more marked difference in development of physical conditions in long term view on the other side (see Figure 4). Clinical experience with mesh implants leads to the conclusion, that at least 30 % of all patients undergoing hernia repair report a long term sensation of foreign body in the groin. Therefore the importance of light weight meshes has been outpointed by several prospective randomized studies lately [1,25]. Patients elected for Lichtenstein repair and receiving either a heavy weight (100-110 g/m 2 ) or a light weight composite mesh (27-30 g/m 2 ) did not present differences in early or late 71

complication rates. Pain on exercise was reduced significantly and the feeling of foreign body was reduced from 43.8 to 17.2 % (p = 0.003) [1]. In another trial with patients selected for TAPP repair and the use of either a monofile, heavy weight, rigid mesh or a smooth, heavy weight variant of polypropylene mesh lesser pain development, earlier return to work and higher SF-36 values for the smooth mesh group was documented. Although mesh weight was not significantly different in this study biocompatibility of the smooth polypropylene mesh variant was noted to be significantly higher [25]. Compound meshes like Vypro II (Ethicon) a large-pored multifilamentous polypropylene mesh with supplementary polyglactin 910 multifilaments, were reported to cause fibroplastic reactions and wound complications more often than high or low weight polypropylene meshes. Therefore two meshes (Vypro II composite mesh and a pure polypropylene variant) were compared after inlay implant in a standardized rodent animal model. Histological analysis of inflammatory tissue reaction, fibrosis and granuloma formation showed that total absorption of polyglactin filaments of the Vypro II mesh occurred from day 56 to day 84 after implant. Both the inflammatory and the fibrotic reaction were initially increased in the compound mesh group. These differences disappeared in the postoperative course. After 112 days, inflammation was even less pronounced in the PP + PG mesh group [2]. These results are consistent with our findings. When looking to the evolution of postoperative physical condition we also registered the differences specially for PP PG and PP Ti to be marked in the early postoperative period whereas 12 weeks later results for SF-36 in all 4 mesh types had nearly equaled (see Figure 4). In another animal model (pigs) four different PP meshes (a heavyweight PP = Atrium ; a lightweight PP incorporating absorbable polyglactic acid = Vypro II ; a lightweight PP = Parietene ; and a titanium-coated lightweight PP = Ti-Mesh Extralight) were implanted using the endoscopic total extrapreperitoneal (TEP) technique. Clear differences were found in the shrinkage characteristics of the meshes. In comparison to Atrium (12%) Vypro II mesh shrinkage was significantly bigger (28%) whereas Parietene (7%) and Ti-Mesh (5%) showed lesser shrinkage. The titanium-coated mesh presented a significantly lower inflammatory activity (13.1% partial volume [%PV] vs 34.1%PV and 29.0%PV) than the lightweight meshes Vypro II and Parietene. Mediators in the extracellular matrix like matrix metalloproteinases 1 (MMP-1) transforming growth factor beta (TGF-beta) urokinase plasminogen activator (upa) and type I collagen tended to show the highest expression with Vypro II (13.6, 113.2, 132.7, and 139.5, respectively) and the lowest expression with Ti-Mesh (11.9, 68.5, 92.8, and 75.0, respectively) [3]. These findings may be consistent with our results. Physical condition recovered best in patients with PP PG and PP Ti implants, whereas we could not detect a statistic difference (see Figures 4, 5). Anyway the study outlines the importance of weight reduced meshes in hernia surgery. Typical postoperative complications such as urogenital syndromes with burning sensations, infection and nerval affections of the ilioinguinal nerve, the genital branch of genitofemoral nerve, the iliohypogastric nerve and the nervus cutaneus femoris lateralis have been mentioned in literature. These affections present themselves as paresthesia in the lateral region of the proximal lower extremity and the genital region [6, 7, 10, 11, 12, 13]. Also ischemic orchitis due to disturbance of arterial and venous perfusion from the first to the third postoperative day after endoscopic therapy presenting with a swollen and hurting testicle has been described [14, 15, 16]. Postoperative hematomas, seromas and infections have been reported also. The results of our study indicate once more, that the material used in endoscopic hernia repair has a direct influence on the quality of life of these patients. In all the collectives there was a reduction postoperatively until the 12 th week, but it could be shown impressively that the low weight polypropylene mesh, compound-mesh and titanium coated light weight meshes cause this at a lesser extent. The aim of meshes used in hernia repair should be the reinforcement of the abdominal wall without reducing the movement by the scar disk that is formed by the inflammatory reaction. Nevertheless complications like wound infections, adhesion formation or perforation of the intestine should not be caused. Affections like pain with ejaculation, itching with urination and touch-sensitiveness of the testicle on the hernia site should not lead to postoperative reduction in quality of life. The complexity of these demands defines the ideal mesh concerning hernia repair. The results of a study by Klosterhalfen et al. [18, 19, 20] showed that most materials used are far away from being well compatible. The examination of the different polypropylene meshes revealed, that a foreign body reaction was possible even after years. The authors have drawn the conclusion, that the quantity of the used polymer, the size of the pores and the surface of the mesh, that may come in contact with the body, influence the inflammatory process and the integration of the mesh. In another study the same authors found that modifications of the used polypropylene mesh could reduce the postoperative complications and improve the quality of life [21]. Physical characteristics as weight, 72

size of the surface, size of the pores and the structure of the mesh seem to have a greater influence on the compatibility of the mesh than the material on its own. In another prospective study a beta glucan-coated mesh was implanted in 115 patients with inguinal hernia [27]. Oat beta glucan is an entirely natural product that eliminates the risk of viral or prion contamination associated with the use of collagen of animal origin. The authors describe a low incidence of chronic pain and a low recurrence rate in the two-year follow up. They draw the conclusion that a light-weight, smooth polypropylene mesh coated with oat beta glucan optimizing tissue incorporation leads towards the ideal mesh. 5. Conclusions It becomes more and more likely that compound meshes do not stand for the gold standard in mesh repair. The titanium coated mesh offers more overall comfort to patients with inguinal hernia repair than low-weight and compound polypropylene meshes. The presented study shows clearly, that weight and coating do have an important influence on the postoperative course in hernia patients. Endoscopic technique turned out to seem superior to Lichtenstein repair in this non-randomized series. Therefore we claim for the projection of a prospective randomized trial comparing TAPP or TEP with Lichtenstein repair using Titanium coated polypropylene meshes. Hernia surgery should abstain from a general use of high weight polypropylene meshes. References 1. Post S, Weiss B, Willer M, Neufang T, Lorenz D, Randomized clinical trial of lightweight composite mesh for Lichtenstein inguinal hernia repair, Br J Surg, 91 (2004) 44-48. 2. Rosch R, Junge K, Quester R, Klinge U, Klosterhalfen B, Schumpelick V, Vypro II mesh in hernia repair: impact of polyglactin on long-term incorporation in rats, Eur Surg Res, 35 (2003) 445-450. 3. Scheidbach H, Tamme C, Tannapfel A, Lippert H, Köckerling F, In vivo studies comparing the biocompatibility of various polypropylene meshes and their handling properties during endoscopic total extraperitoneal (TEP) patchplasty: an experimental study in pigs, Surg Endosc, 18 (2004) 211-220. 4. Trupka A, Hallfeldt K, Schmidbauer S, Schweiberer L, Incisional hernia repair with an underlay polypropylene mesh plasty: an excellent technique from French hernia surgeons, Chirurg, 69 (1998) 766. 5. Schumpelick V, Conze J, Klinge U, Die präperitoneale Netzplastik (PNP) in der Reparation der Narbenhernie. Eine vergleichende retrospektive Studie, Chirurg, 67 (1996) 1028. 6. Schumpelick V, Kingsnorth G, Incisional hernia of the abdominal wall, Springer, Berlin (1999). 7. Leber GE, Garb JL, Alexander AI, Reed WP, Long-term complications associated with prosthetic repair of incisional hernias, Arch Surg, 133 (1998) 378. 8. Amid P, Classification of biomaterials and their related complications in abdominal wall hernia surgery, Hernia, 1 (1997) 5. 9. Chandler SB, Studies on the inguinal region, Anat. Rec, 107 (1950) 93. 10. Corbitt JD Jr, Laparoscopic herniorrhaphy, Surg. Laparosc. Endosc, 1 (1991) 23. 11. Ger R, Laparoskopische Hernienoperation, Chirurg, 62 (1991) 266. 12. Popp LW, Endoskopische Hernioplastik, Chirurg, 62 (1991) 336. 13. Schafmayer A, Neufang T, Barthel M, Schleef J, Lüdtke FE, Lepsien G. Endoskopischer Hernienverschluß, Chirurg, 63 (1992) 357. 14. Schumpelick V, Schippers E, Kupczyk-Joeris D. Fehler und Gefahren in der Hernienchirurgie, Chirurg, 64 (1993) 237. 15. Phillips EH, Arregui M, Carroll BJ, Corbitt J, Crafton WB, Fallas MJ, Filipi C, Fitzgibbons RJ, Fanklin MJ, McKernan B, et al., Incidence of complications following laparoscopic hernioplasty, Surg Endosc, 9 (1995) 16-21. 16. Jarhult J, Hakanson C, Akerud L, Laparoscopic treatment of recurrent inguinal hernias: experience from 281 operations, Surg Laparosc Endosc, 9 (1999) 115-118. 17. Batorfi J, Kelemen O, Vizsy L, Simon E, Balint A, Posfai G, Transabdominal preperitoneal herniorraphy: technique and results, Acta Chir Hung, 36 (1997) 18-21. 18. Klosterhalfen B, Klinge U, Hermanns B, Schumpelick V, Pathology of traditional surgical nets for hernia repair after long-term implantation in humans, Chirurg, 71 (2000) 43-51. 19. Klosterhalfen B, Klinge U, Schumpelick V, Functional and morphological evaluation of different polypropylene-mesh modifications for abdominal wall repair, Biomaterials, 19 (1998) 2235-2246. 73

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