Use of Resterilized Polypropylene Mesh in Inguinal Hernia Repair: A Prospective, Randomized Study

Evaluation of hernia surgical meshes sterilised with ethylene oxide for adoption under UK regulations

BACKGROUND

Low-cost meshes (LCM) have been successfully used in low-income countries (LIC) over the past decades, demonstrating comparable surgical outcomes to commercial meshes at a fraction of the cost. However, LIC sterilisation standards (autoclave sterilisation at 121 °C) do not meet UK regulations for medical devices, which require either ethylene oxide (EO) sterilisation or steam sterilisation at 134 °C. Therefore, the aim of this study was to sterilise UK LCM and characterise their mechanical properties and in vitro biocompatibility to verify whether EO sterilisation causes changes in the mechanical properties and biocompatibility of LCM.

METHODS

EO sterilised LCM were used. Uniaxial tensile tests were performed to measure mechanical properties. Biocompatibility was measured through viability and morphology of Human Dermal Fibroblasts (HDFs) cultured in mesh-conditioned media, and by calculating the metabolic activity and proliferation of HDFs attached on the meshes, with alamarBlue assay.

RESULTS

Break stress of LCM1 was significantly higher than LCM2 (p < 0.0001), while Young's modulus of LCM1 was significantly lower than LCM2 (p < 0.05) and there was no significant difference in break strain. Viability and morphology showed no significant difference between LCM and control. Attachment and proliferation of HDFs on LCM showed a better proliferation on LCM2 than LCM1, with values similar to the control at the final time point.

CONCLUSIONS

We demonstrated that EO sterilisation affects LCM mechanical properties, but they still have values closer to the native tissues than the commercially available ones. We also showed that in vitro biocompatibility of LCM2 is not affected by EO sterilisation, as HDFs attached and proliferated on the mesh, while EO affected attachment on LCM1. A more detailed cost analysis of the potential savings for healthcare systems around the world needs to be performed to strengthen the cost-effectiveness of this frugal innovation.

Variability in mortality following caesarean delivery, appendectomy, and groin hernia repair in low-income and middle-income countries: a systematic review and analysis of published data

BACKGROUND

Surgical interventions occur at lower rates in resource-poor settings, and complication and death rates following surgery are probably substantial but have not been well quantified. A deeper understanding of outcomes is a crucial step to ensure that high quality accompanies increased global access to surgical care. We aimed to assess surgical mortality following three common surgical procedures--caesarean delivery, appendectomy, and groin (inguinal and femoral) hernia repair--to quantify the potential risks of expanding access without simultaneously addressing issues of quality and safety.

METHODS

We collected demographic, health, and economic data for 113 countries classified as low income or lower-middle income by the World Bank in 2005. We did a systematic review of Ovid, MEDLINE, PubMed, and Scopus from Jan 1, 2000, to Jan 15, 2015, to identify studies in these countries reporting all-cause mortality following the three commonly undertaken operations. Reports from governmental and other agencies were also identified and included. We modelled surgical mortality rates for countries without reported data using a two-step multiple imputation method. We first used a fully conditional specification (FCS) multiple imputation method to establish complete datasets for all missing variables that we considered potentially predictive of surgical mortality. We then used regression-based predictive mean matching imputation methods, specified within the multiple imputation FCS method, for selected predictors for each operation using the completed dataset to predict mortality rates along with confidence intervals for countries without reported mortality data. To account for variability in data availability, we aggregated results by subregion and estimated surgical mortality rates.

FINDINGS

From an initial 1302 articles and reports identified, 247 full-text articles met our inclusion criteria, and 124 provided data for surgical mortality for at least one of the three selected operations. We identified 42 countries with mortality data for at least one of the three procedures. Median reported mortality was 7·9 per 1000 operations for caesarean delivery (IQR 2·8-19·9), 2·2 per 1000 operations for appendectomy (0·0-17·2), and 4·9 per 1000 operations for groin hernia (0·0-11·7). Perioperative mortality estimates by subregion ranged from 2·8 (South Asia) to 50·2 (East Asia) per 1000 caesarean deliveries, 2·4 (South Asia) to 54·0 (Central sub-Saharan Africa) per 1000 appendectomies, and 0·3 (Andean Latin America) to 25·5 (Southern sub-Saharan Africa) per 1000 hernia repairs.

INTERPRETATION

All-cause postoperative mortality rates are exceedingly variable within resource-constrained environments. Efforts to expand surgical access and provision of services must include a strong commitment to improve the safety and quality of care.

FUNDING

None.

Prophylactic antibiotic use in elective inguinal hernioplasty in a trauma center

PURPOSE

In this double-blind prospective randomized trial, our objective was to investigate the effect of antibiotic prophylaxis in patients undergoing elective inguinal hernia surgery with mesh repair in a large-volume tertiary referral trauma center.

METHODS

Eligible patients were assigned randomly to either an antibiotic prophylaxis group or a control group. Patients in the prophylaxis group were given 1 g cefazolin by IV bolus injection whereas the placebo control group received an equal volume of sterile saline preoperatively. A Lichtenstein repair was done in all cases. The patients were examined for surgical site infection (SSI) and other postoperative local complications before discharge, and reexamined 3, 5, 7, and 30 days after discharge.

RESULTS

Groups were well matched for age, sex, coexisting diseases, ASA scores, type of hernia, type of anesthesia, duration of surgery. Incidence of infection was 7% in the control group (7/100) and 5% in the prophylaxis group (5/100) (P = 0.38). All the infections were superficial and responded well to drainage and proper antibiotic therapy. All other postoperative complications were similar in the two groups.

CONCLUSIONS

In our settings antibiotic prophylaxis has no significant effect on the incidence of SSI in elective repair of inguinal hernias with mesh. The most effective way to reduce the incidence of infection in prosthetic repair may be a specific center for treatment of abdominal wall hernias.

Resterilized mesh in repair of abdominal wall defects in rats

A variety of negative opinions about repeated usage of relatively expensive resterilized synthetic meshes have been considered. It had been stated that resterilized polypropylene meshes inhibits fibroblastic activity, decreases proliferative activity, and increases apoptosis in human fibroblast culture, in vitro. The purpose of this study is the in vivo evaluation of the resterilized mesh repairs of abdominal hernia defects in rat models of incisional hernia by comparing primer repair and original mesh repairs. The rats (n = 22) were separated into three groups. While the abdominal defect was repaired by primary suture in the control group (CG), the defects were repaired by original mesh (OG) or resterilized mesh (RG) in mesh-repaired groups. After 21 days, the rats were evaluated for tissue tensile strengths, tissue hydroxyproline levels, tissue inflammation, fibrosis, and apoptosis. Although the tensile strengths in OG and RG were significantly higher than those of CG (p < .05 and p < .05), there was no significant difference between two groups. The tissue hydroxyproline levels in OG and RG were also higher than those of CG. The difference was not significant between the two groups. The inflammation and fibrosis indexes in OG and RG were significantly higher than those of CG (p < .0001 for both), but there was no difference between groups. While the apoptosis index in OG and RG was also higher than that of CG (p < .0001 for both), there was no significant difference between OG and RG. The usage of resterilized mesh in abdominal wall repair did not reduce the tissue tensile strength, did not affect the tissue hydroxyproline levels, did not decrease the fibrosis, and did not increase the tissue inflammation and apoptosis. In conclusion, usage of resterilized meshes in abdominal wall defects was as safe as sterilized meshes.

Wound infections due to Mycobacterium fortuitum after polypropylene mesh inguinal hernia repair

Mycobacterium fortuitum complex is a group of rapidly growing mycobacteria (RGM). These opportunistic pathogens are frequently associated with infections related to surgical procedures involving biomaterials. Two cases of Mycobacterium fortuitum infection occurred in a prospective study of inguinal hernia prosthesis repairs. These infections differed from those caused by other bacteria in terms of pathogenic mechanisms, clinical manifestation and resistance to both prophylactic and therapeutic antibiotics.