Cytomorphological Effects of Lightweight and Heavyweight Polypropylene Mesh on the Ilioinguinal Nerve: An Experimental Study.

Objective This study aimed to investigate the cytomorphological effects of heavyweight and lightweight mesh on the ilioinguinal nerve in an experimental animal model. Methods Sixteen New Zealand male rabbits were included in the study. The left inguinal regions of the first six animals were assigned as controls and the right inguinal regions were assigned as the sham group. The left inguinal regions of the remaining 10 animals were assigned as the lightweight mesh group and the right inguinal regions were assigned as the heavyweight mesh group. No intervention was performed in the control group. In the sham group, only ilioinguinal nerve exploration was performed. In mesh groups, ilioinguinal nerve exploration was performed and the mesh was implanted on the ilioinguinal nerve. After three months, ilioinguinal nerve specimens were excised from both sides for cytomorphological examination. Results Myelin sheath thickening, separation of the myelin layers, and myelin vacuolization were more pronounced in the heavyweight mesh group compared to the lightweight mesh group. The G-ratio was moderately increased in the heavyweight mesh group when compared to other groups. The ratio of fibers with ≤4 µm diameter was higher in the lightweight mesh group compared to other groups, and the ratio of fibers with ≥9 µm diameter was higher in the heavyweight mesh group than in the other groups (p<0.05). Conclusion Both of the meshes induce cytomorphological alterations on the adjacent nerve tissues caused by foreign body reaction and compression. Ilioinguinal nerve degeneration was more pronounced in the heavyweight mesh than in the lightweight mesh. Histological alterations on the ilioinguinal nerves caused by different meshes may be related to chronic pain after hernia surgery. We believe our study will serve as a guide for future studies on the topic.

Definition of Mesh Weight and Pore Size in Groin Hernia Repair: A Systematic Scoping Review of Randomised Controlled Trials.

Introduction: Groin hernia literature often uses the terms light- and heavyweight and small or large pores to describe meshes. There is no universal definition of these terms, and the aim of this scoping review was to assess how mesh weight and pore sizes are defined in the groin hernia literature. Methods: In this systematic scoping review, we searched PubMed, Embase, and Cochrane CENTRAL. We included randomised controlled trials with adults undergoing groin hernia repair with the Lichtenstein or laparoscopic techniques using a flat permanent polypropylene or polyester mesh. Studies had to use the terms lightweight, mediumweight, or heavyweight to be included, and the outcome was to report how researchers defined these terms as well as pore sizes. Results: We included 48 studies with unique populations. The weight of lightweight meshes ranged from 28 to 60 g/m2 with a median of 39 g/m2, and the pore size ranged from 1.0 to 4.0 mm with a median of 1.6 mm. The weight of heavyweight meshes ranged from 72 to 116 g/m2 with a median of 88 g/m2, and the pore size ranged from 0.08 to 1.8 mm with a median of 1.0 mm. Only one mediumweight mesh was used weighing 55 g/m2 with a pore size of 0.75 mm. Conclusion: There seems to be a consensus that meshes weighing less than 60 g/m2 are defined as lightweight and meshes weighing more than 70 g/m2 are defined as heavyweight. The weight terms were used independently of pore sizes, which slightly overlapped between lightweight and heavyweight meshes.

Update in Transvaginal Grafts: The Role of Lightweight Meshes, Biologics, and Hybrid Grafts in Pelvic Organ Prolapse Surgery.

Transvaginal mesh/grafts have been popularized over the past 20 years in an attempt to improve the longevity of traditional vaginal pelvic organ prolapse (POP) surgery. Several national bodies have concluded that the proposed benefits of mesh/graft implantation are outweighed by the significant increase in surgery complications related to these products. As a consequence mesh products for vaginal POP surgery have been withdrawn from use in many countries. This article is a narrative review of newer mesh and graft products including lightweight polypropylene mesh products, biological grafts, hybrid grafts, and tissue engineered grafts.

Assessing pelvic organ prolapse recurrence after minimally invasive sacrocolpopexy: does mesh weight matter?

INTRODUCTION AND HYPOTHESIS: There has been a trend toward the use of ultra-lightweight mesh types for minimally invasive sacrocolpopexy. We hypothesized that ultra-lightweight mesh would have a greater proportion of composite anatomical pelvic organ prolapse recurrence than lightweight mesh. METHODS: Retrospective cohort study of minimally invasive sacrocolpopexies at two academic institutions from 2009 to 2016. Our primary outcome was composite anatomical prolapse recurrence, defined as prolapse beyond the hymen or retreatment with pessary or surgery, compared between ultra-lightweight (≤21 g/m2 [range 19-21]) and lightweight (>21 g/m2 [range 35-50]) mesh types. We assessed time to prolapse recurrence using Kaplan-Meier and Cox regression. RESULTS: The cohort consisted of 1,272 laparoscopic (n = 530, 41.7%) and robotic-assisted sacrocolpopexies (n = 742, 58.4%). Lightweight mesh was used in 745 procedures (58.6%) and ultra-lightweight mesh in 527 (41.4%). The lightweight mesh had longer median follow-up than the ultra-lightweight group (344 [IQR 50-670] vs 143 days [IQR 44-379], p < 0.01). There was no difference in composite anatomical prolapse recurrence between lightweight and ultra-lightweight mesh (54 [7.2%] vs 35 [6.6%], p = 0.68). Ultra-lightweight mesh demonstrated a shorter time to prolapse recurrence (p < 0.01), which remained significant on multivariate Cox regression (HR 2.38 [95% CI 1.47-3.87]). The lightweight mesh had significantly more mesh complications (43 [5.8%] vs 7 [1.3%], p < 0.01). CONCLUSIONS: Ultra-lightweight mesh for minimally invasive sacrocolpopexy was not associated with a higher proportion of composite anatomical prolapse recurrence; however, it was associated with a shorter time to recurrence. Longer follow-up is needed to assess the clinical importance of this finding, particularly given the trade-off of more complications with lightweight mesh.

Mechanical properties of warp-knitted hernia repair mesh with various boundary conditions.

In this paper, two most representative hernia repair meshes were prepared with 0.15 mm polypropylene monofilaments via warp knitting technology, and their mechanical properties were tested in various aspects. Meanwhile, a focused investigation of the boundary conditions between the sutures and the mesh was simulated in several directions innovatively. The results revealed that the hernia repair mesh with different structures has different mechanical properties, and the mechanical properties of standard hernia repair mesh were superior to that of lightweight hernia repair mesh. In order to reduce foreign body sensation and postoperative adverse reactions significantly, the lightweight hernia repair mesh may be preferred. At the same time, the mesh should be placed in the proper direction to comply with the anisotropy of abdominal wall during operation. The area where the hernia mesh is in contact with the sutures was vulnerable to damage. The curved or wrinkled area of the hernia repair mesh increases with the increase of load, which may lead to poor tissue growth, a strong inflammatory response, and even the recurrence of the hernia. Therefore, the hernia repair meshes with different structures may require unique suture techniques. And they also should be further treated prior to implantation. This study provides a theoretical basis for development, utilization and improvement of meshes. Further research will focus on the biomechanical properties of the mesh after implantation in vivo studies.

Lightweight Versus Heavyweight Mesh in Laparoscopic Inguinal Hernia Repair: An Updated Systematic Review and Meta-Analysis of Randomized Trials.

Background: There is no consensus on whether lightweight mesh (LWM) is better than heavyweight mesh (HWM) in laparoscopic inguinal hernia repair (LIHR). This study aims to update the previous reviews and to analyze present randomized controlled studies comparing LWM versus HWM in LIHR systematically. Methods: We searched PubMed, Embase, and Cochrane Library for randomized controlled trials (RCTs), which compared LWM with HWM in adults with LIHR. All eligible data of outcomes were quantitatively analyzed using Revman 5.3 software or qualitatively described. The outcomes included chronic pain, moderate-severe chronic pain, recurrence, foreign body sensation, influence on sexual life and male fertility (pain with ejaculation, testicular pain, etc.). Results: We included 12 RCTs that analyzed 3092 hernias. The difference between LWM and HWM groups at any follow-up time was not significant in chronic pain and foreign body sensation. Compared with HWM group, patients in LWM group had a similar risk of postoperative moderate-severe chronic pain at 3 and 12 months follow-up, a slightly increased risk of developing moderate-severe chronic pain at >12 months follow-up (risk ratio [RR] = 3.20, 95% confidence interval [CI] 1.05-9.75, P = .04), and a higher risk of recurrence rate (RR = 2.28, 95% CI 1.17-4.44, P = .02). At long-term follow-up, the influences of LWM and HWM on sexual life and male fertility were comparable. Conclusion: LWMs do not show advantages in chronic pain, foreign body sensation as well as the influence on sexual life and male fertility, and may increase hernia recurrence rates for LIHR. In addition, a higher incremental cost and lower incremental effect of LWMs make conventional HWMs preferred choice for LIHR.

Amyand hernia repair with mesh and appendectomy.

BACKGROUND: Amyand hernias have been described in case reports in the literature and are a rare occurrence in the career of a surgeon. Their management is even less well described and often poses problems in the management of repair due to concerns with contamination associated with appendectomy. Here, we describe a patient with an Amyand hernia seen on CT imaging preoperatively, who underwent appendectomy along with a lightweight mesh plug repair of his hernia. CASE PRESENTATION: An 88-year-old male presented with a right groin bulge and underwent preoperative imaging which indicated the presence of his appendix within his hernia. He was taken to the operating room electively where an appendectomy was performed due to significant chronic inflammatory changes. A lightweight mesh plug was used to repair the hernia to prevent recurrence. He did well post operatively without any complications. CONCLUSIONS: A review of the literature supports the use of mesh repair in these of hernias even with appendectomy at the time of the hernia repair. This will guide surgeons who encounter this clinical rarity in their practice.

Lower recurrence rate with heavyweight mesh compared to lightweight mesh in laparoscopic totally extra-peritoneal (TEP) repair of groin hernia: a nationwide population-based register study.

PURPOSE: Lightweight meshes (LWM) have shown benefits compared to heavyweight meshes (HWM) in terms of less postoperative pain and stiffness in open inguinal hernia repair. It appears to have similar advantages also in TEP, but concerns exist if it may be associated with higher recurrence rates. The aim of the study was to compare reoperation rate for recurrence of LWM to HWM in laparoscopic totally extra-peritoneal (TEP) repair. METHODS: All groin hernias operated on with TEP between 1 January 2005 and 31 December 2013 at surgical units participating in The Swedish Hernia Register were eligible. Data included clinically important hernia variables. Primary endpoint was reoperation for recurrence. Median follow-up time was 6.1 years (0-11.5) with minimum 2.5 years postoperatively. RESULTS: In total, 13,839 repairs were included for statistical analysis and 491 were re-operated for recurrence. Multivariate analysis demonstrated significantly increased risk of reoperation for recurrence in LWM 4.0% (HR 1.56, P < 0.001) compared to HWM 3.2%. This was most evident in direct hernias (HR 1.75, P < 0.001) and in hernia repairs with a defect > 3 cm (HR 1.54, P < 0.021). The risk of recurrence with use of LWM in indirect hernias and in hernia repairs with a defect < 1.5 cm was more comparable to HWM. CONCLUSIONS: Lightweight meshes were associated with an increased risk of reoperation for recurrence compared to HWM. While direct hernias and larger hernia defects may benefit from HWM to avoid increased recurrence rates, LWM is recommended to be used in indirect and smaller hernia defects in TEP repair.

Pain and quality of life after inguinal hernia surgery: a multicenter randomized controlled trial comparing lightweight vs heavyweight mesh (Supermesh Study).

Mesh repair has significantly reduced recurrence rate after groin hernia surgery. Recently, attention has shifted to issues such as chronic pain and discomfort, leading to development of lightweight and partially re-absorbable meshes. The aim of the study was to evaluate the effect of lightweight mesh vs heavyweight mesh on post-operative pain, discomfort and quality of life in short and medium term after inguinal hernia surgery. Eight hundred and eight patients with primary inguinal hernia were allocated to anterior repair (Lichtenstein technique) using a lightweight mesh (Ultrapro®) or a heavyweight mesh (Prolene®). Primary outcomes were incidence of chronic pain and discomfort at 6-month follow-up. Secondary endpoints were quality of life (QoL), pain and complication at 1 week, 1 and 6 months. At 6 months, 25% of patients reported pain of some intensity; severe pain was reported by 1% of patients in both groups. A statistically significant difference in favour of lightweight mesh was found at multivariable analysis for pain (1 week and 6 months after surgery: p = 0.02 and p = 0.04, respectively) and QoL at 1 month and 6 months (p = 0.05 and p = 0.02, respectively). There was no difference in complication rate and no hernia recurrences were detected. The use of lightweight mesh in anterior Lichtenstein inguinal hernia repair significantly reduced the incidence of pain and favourably affected the perceived quality of life at 6 months after surgery compared to heavyweight mesh.

Prospective randomized controlled trial comparing partially absorbable lightweight mesh and multifilament polyester anatomical mesh in laparoscopic inguinal hernia repair.

INTRODUCTION: Tension-free mesh repair is currently the gold standard treatment for inguinal hernia. Recent evidence has shown that both open and laparoscopic approaches to inguinal hernia repair can achieve good results. Lots of meshes with different properties are available on the market, but direct comparisons between them are scare. We conducted a prospective randomized controlled trial comparing a partially absorbable lightweight mesh (ULTRAPRO™) and a multifilament polyester anatomical mesh (Parietex™) in laparoscopic total extraperitoneal inguinal hernia repair. METHODS: This study was a single-center, prospective randomized controlled trial to compare the surgical handling and clinical outcomes between two different types of meshes. All operations were performed using a standardized operative protocol. This study was approved by the Institutional Review Board of the Hong Kong East Cluster Health Service in 2009 (reference number: 2009-087). The study was registered in the Australian New Zealand Clinical Trial Registry (ACTRN12610000031066). RESULTS: From October 2009 to August 2011, 85 laparoscopic total extraperitoneal inguinal hernia repairs were performed. The mean mesh handling time was 152 s for the ULTRAPRO group and 206 s for the Parietex group (P = 0.001). There were three cases of seroma formation in the ULTRAPRO group and nine in the Parietex group (P = 0.02). The overall recurrence rate was 2.5%. CONCLUSION: It took less time to manipulate the flat mesh (ULTRAPRO) than the anatomical mesh (Parietex) in laparoscopic total extraperitoneal inguinal hernia repair, but the time difference was small. Lightweight mesh and heavyweight mesh offered similar clinical outcomes in terms of discomfort sensation and foreign body sensation during long-term follow-up.

Laparoscopic ventral hernia repair using a novel intraperitoneal lightweight mesh coated with hyaluronic acid: 1-year follow-up from a case-control study using the Hernia-Club registry.

PURPOSE: A case-control study was performed to compare laparoscopic ventral hernia repair (LVHR) using the Ventralight ST™ lightweight surgical mesh with LVHR using other types of mesh. METHODS: Adult patients undergoing intraperitoneal implantation of Ventralight ST™ during LVHR (Ventralight ST™ group; VG) over a 2-year period (2011-2013) were identified from the prospective French Hernia-Club registry. Patients undergoing elective LVHR using other types of intraperitoneal mesh in the first semester of 2013 formed the control group (CG). Patient, hernia and surgical characteristics, and postoperative outcomes after 8 days, 1 month, and 1 year were compared between the two groups. RESULTS: The VG comprised 90 LVHRs in 85 patients, and the CG 86 LVHRs in 81 patients. Patient, hernia and surgical characteristics were similar between the two groups, apart from the method of mesh fixation and the number of procedures involving fascial closure. A low rate of minor complications was observed in both groups at 1 month [4.4 % (VG) and 2.3 % (CG)], and the level of postoperative pain was similar in the two groups at Day 8 and 1 month. After 1 year, no complications, recurrences or cases of chronic pain had occurred in either group, and Quality-of-Life outcomes were similar. Patients rated their procedure as excellent or good in 96 % (VG) and 92 % (CG) of cases. CONCLUSIONS: Ventralight ST™ mesh is effective and well tolerated in LVHR, producing very low complication and recurrence rates in the short and medium term. The results are comparable to those achieved with other types of mesh.

A prospective randomised controlled trial comparing chronic groin pain and quality of life in lightweight versus heavyweight polypropylene mesh in laparoscopic inguinal hernia repair.

BACKGROUND: The aim of our study was to compare chronic groin pain and quality of life (QOL) after laparoscopic lightweight (LW) and heavyweight (HW) mesh repair for groin hernia. MATERIALS AND METHODS: One hundred and forty adult patients with uncomplicated inguinal hernia were randomised into HW mesh group or LW mesh group. Return to activity, chronic groin pain and recurrence rates were assessed. Short form-36 v2 health survey was used for QOL analysis. RESULTS: One hundred and thirty-one completed follow-up of 3 months, 66 in HW mesh group and 65 in LW mesh group. Early post-operative convalescence was better in LW mesh group in terms of early return to walking (P = 0.01) and driving (P = 0.05). The incidence of early post-operative pain, chronic groin pain and QOL and recurrences were comparable. CONCLUSION: Outcomes following laparoscopic inguinal hernia repair using HW and LW mesh are comparable in the short-term as well as long-term.

Chronic pain after open inguinal hernia repair.

Following the widespread use of mesh repairs, recurrence rates after inguinal hernia surgery have become acceptable and focus has shifted from recurrence to chronic pain. Although pain can be controlled with analgesics, chronic postsurgical pain is a major clinical problem, which can significantly influence the patient's quality of life. The rate of chronic pain after inguinal hernia mesh repair can reach 51.6%. The reasons for posthernioplasty chronic pain are often unclear. It has been linked to nerve injury and nerve entrapment, but there is also association between the rate of chronic pain and the type of mesh used for hernia repair. As there are >160 meshes available in the market, it is difficult to choose a mesh whose usage would result in the best outcome. Different mesh characteristics have been studied, among them weight of mesh has probably gained the most attention. The choice of adequate therapy for chronic groin pain after inguinal hernia repair is controversial. The European Hernia Society recommends that a multidisciplinary approach at a pain clinic should be considered for the treatment of chronic postoperative pain. Although surgical treatment of chronic posthernioplasty pain is limited because of the lack of relevant research data, resection of entrapped nerves, mesh removal in the case of mesh related pain or removal of fixation sutures can be beneficial for the patient with severe pain after inguinal hernia surgery. One drawback of published studies is the lack of consensus over definition of chronic pain, which makes it complicated to compare the results of different studies and to conduct meta-analyses and systematic reviews. Therefore, a uniform definition of chronic pain and its best assessment methods should be developed in order to conduct top quality multicenter randomized trials. Further research to develop meshes with optimal parameters is of vital importance and should be encouraged.

Three-month results of the effect of Ultrapro or Prolene mesh on post-operative pain and well-being following endoscopic totally extraperitoneal hernia repair (TULP trial).

BACKGROUND: Recurrence rates after inguinal hernia repair have been reduced to a few per cent, since mesh repair has become standard of care. Lightweight meshes reduce post-operative pain and stiffness in open anterior repair, but for endoscopic repair, the discussion about this benefit is ongoing. This study was done to analyse the effects of lightweight mesh versus heavyweight mesh following endoscopic totally extraperitoneal (TEP) hernia repair. METHODS: In a single-centre double-blindly randomized clinical trial, 950 patients with unilateral primary inguinal hernia were randomized to undergo endoscopic TEP using either an Ultrapro(®) or a Prolene(®) mesh. Data were collected by validated questionnaires at day 1, day 7, after 6 weeks and after 3 months, and clinical assessment was performed after 3 months. The presence of groin pain after 3 months, defined as an NRS score >3, was evaluated as the primary outcome measure. Secondary outcomes were foreign body feeling and the impact of pain and foreign body feeling on daily activities. RESULTS: At 3-month follow-up, the incidence of pain (NRS 4-10) was 2 versus 0.9 % in the lightweight and heavyweight mesh group, respectively (p = 0.17). Pain interfered with daily activities in 1.7 % of the lightweight and 1.5 % of heavyweight group. In the lightweight group, 20 % of patients reported a foreign body feeling versus 18 % in the heavyweight group (p = 0.62). No differences between the groups were observed regarding time to return to work, interference with sports and sexual activities, testicular pain and ejaculatory pain. Severe preoperative pain (OR 2.01, 95 % CI 1.21-3.35, p = 0.01) was the only independent predictor of any post-operative pain after 3 months. CONCLUSION: Three months after TEP inguinal repair, there were no significant differences between lightweight and heavyweight mesh use regarding the incidence of pain, foreign body feeling or any other endpoint.

Standard polypropylene mesh vs lightweight mesh for Lichtenstein repair of primary inguinal hernia: a randomized controlled trial.

PURPOSE: The aim of the present clinical study was to compare early and late outcomes after inguinal hernia repair with the heavyweight mesh (HW) and lightweight mesh (LW) during a 3 year follow-up period. METHODS: 226 patients were randomized into LW and HW mesh groups, both of which underwent unilateral primary inguinal hernia repair via the Lichtenstein technique. Wound complications (infection, hematoma, seroma), hernia recurrence, pain and feeling of foreign body in inguinal area were determined in patients. Pain was measured by visual analogue scale. RESULTS: No statistical difference has been found between LW and HW groups by wound complication (P = 0.80). One case of hernia recurrence has been mentioned in both groups one year after hernioplasty. But there was no detectable difference between the two groups. No significant difference has been found between LW and HW groups by frequency of chronic pain 7 days, 1 and 3 months, 1, 2, and 3 years after surgery. As for the feeling of foreign body in groin it is similar in both groups after 1 and 3 months. Level of feeling of foreign body was significantly lower in LW group 1, 2, and 3 years after surgery, than in HW group (P = 0.03, P = 0.02, P = 0.02, respectively). CONCLUSION: Our research shows no significant difference in wound complications, hernia recurrence and chronic pain after Lichtenstein hernioplasty, by using of LW and HW meshes. The usage of the LW mesh was associated with less feeling of foreign body than that of the HW mesh, what can be considered as prevalence of LW mesh hernioplasty.

Surgical options in lumbar hernia: laparoscopic versus open repair. A long-term prospective study.

OBJECTIVE: To determine the safety and effectiveness of laparoscopic lumbar hernia repair. DESIGN: Prospective clinical study. SETTING: Abdominal wall unit, university hospital. PATIENTS: Between January 1995 and December 2008, data from 55 consecutive patients who had undergone laparoscopic (n = 35) or open (n = 20) lumbar hernia repair. MAIN OUTCOME MEASURES: The primary endpoint was recurrence; secondary endpoints were patient outcomes (morbidity, pain, and return to normal activity). RESULTS: Mean operating time (P = .01), hospital stay, return to normal activity, analgesic consumption, and pain at 1 month (P < .001) were significantly less in the laparoscopic group. Complications were similar in the 2 groups (37% vs 40%, respectively; P = .50). Traumatic hernias increased local complications versus incisional lumbar hernias (71.4% vs 29%; P = .007). Consumption of analgesics (6.8 ± 6.5 vs 18.1 ± 9.1; P < .001) and pain during the first month (no pain: 90% vs 54.3%; P = .015) were significantly less with a lightweight versus medium-weight mesh. The risk factors associated with recurrences development were localization (P = .01) and size (P = .008). Recurrence rates were 2.9% in the laparoscopic group and 15% in the open group (P = .13). CONCLUSIONS: Outcomes did not differ with respect to morbidity and recurrence rate after long-term follow-up; however, this study suggested that laparoscopic approach for lumbar hernia is safe, effective, and more efficient than open repair and can be considered the procedure of choice. Open surgery may be considered the best option in the diffuse hernias with size larger than 15 cm.