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.

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.

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.
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.
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.
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.

BACKGROUND: 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%.
CONCLUSIONS: 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.

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.
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.
CONCLUSIONS: Outcomes following laparoscopic inguinal hernia repair using HW and LW mesh are comparable in the short-term as well as long-term.

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.
CONCLUSIONS: 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.

OBJECTIVE: 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).
CONCLUSIONS: 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.