Self-adhesive hydrogel meshes reduce tissue incorporation and mechanical behavior versus microgrips self-fixation: a preclinical study

Purpose Atraumatic mesh fixation for abdominal hernia repair has been developed to avoid the disadvantages of classical fixation with sutures, which is considered a cause of chronic pain and discomfort. This study was designed to analyze, in the short and medium term, the biological and mechanical behavior of two self-fixing meshes compared to that of a polypropylene (PP) mesh fixed with a cyanoacrylate (CA) tissue adhesive. Methods Partial abdominal wall defects (6 × 4 cm) were created in New Zealand rabbits (n = 36) and repaired using a self-adhesive hydrogel mesh (Adhesix™), a self-gripping mesh (ProGrip™) or a PP mesh fixed with CA (Surgipro™ CA). After 14 and 90 days, the host tissue incorporation, macrophage response and biomechanical strength were examined. Results At 14 and 90 days, the ProGrip and Surgipro CA meshes showed good host tissue incorporation; however, the Adhesix implants presented poor integration, seroma formation and a higher degree of shrinkage. The Adhesix hydrogel was completely reabsorbed at 14 days, whereas ProGrip microhooks were observed at all study times. The macrophage response was higher in the ProGrip and Surgipro CA groups at 14 and 90 days, respectively, and decreased over time. At 90 days, the ProGrip implants showed the highest tensile strength values and the Adhesix implants showed the highest failure stretch. Conclusion Meshes with mechanical microgrip self-fixation (ProGrip) show better biological and mechanical behavior than those with adhesive hydrogel (Adhesix) in a preclinical model of abdominal hernia repair in rabbits.

Mesh fixation techniques for inguinal hernia repair: an overview of systematic reviews of randomised controlled trials

Purpose Inguinal hernia repair using surgical mesh is a very common surgical operation. Currently, there is no consensus on the best technique for mesh fixation. We conducted an overview of existing systematic reviews (SRs) of randomised controlled trials to compare the risk of chronic pain and recurrence following open and laparoscopic inguinal hernia repairs using various mesh fixation techniques. Methods We searched major electronic databases in April 2020 and assessed the methodological quality of identified reviews using the AMSTAR-2 tool. Results We identified 20 SRs of variable quality assessing suture, self-gripping, glue, and mechanical fixation. Across reviews, the risk of chronic pain after open mesh repair was lower with glue fixation than with suture and comparable between self-gripping and suture. Incidence of chronic pain was lower with glue fixation than with mechanical fixation in laparoscopic repairs. There were no significant differences in recurrence rates between fixation techniques in open and laparoscopic mesh repairs, although fewer recurrences were reported with suture. Many reviews reported wide confidence intervals around summary estimates. Despite no clear evidence of differences among techniques, two network meta-analyses (one assessing open repairs and one laparoscopic repairs) ranked glue fixation as the best treatment for reducing pain and suture for reducing the risk of recurrence. Conclusion Glue fixation may be effective in reducing the incidence of chronic pain without increasing the risk of recurrence. Future research should consider both the effectiveness and cost-effectiveness of fixation techniques alongside the type of mesh and the size and location of the hernia defect.

P149 THE IMPACT OF COVID-19 ON TACKOMESH RANDOMISED CONTROLLED TRIAL COMPARING SPIRAL-TACK MESH-FIXATION DEVICES IN LAPAROSCOPIC INCISIONAL HERNIA REPAIR USING THE MANCHESTER TECHNIQUE

Aim Provide a report on all patients who underwent laparoscopic incisional hernia repair as part of the TACKoMesh RCT prior to unblinding of treatment arms. Material and Methods Trial recruitment was for primary incisional hernia with a defect diameter of 3–10cm. 63 patients (target 74-136) were operated on prior to the outbreak of COVID-19. Post-operative pain is the primary trial outcome. Surgery was performed with either spiral-tack mesh-fixation device (Protack (permanent) or Reliatack (absorbable)), Symbotex IPOM mesh, and fascial closure with no 1 Maxon suture(s) using extracorporeal knot ties – the Manchester Technique. Data was collected on trial forms and lifestyle questionnaires (SF-36 and CCS). All data were explored and described in RStudio v1.4.1106. Results Patients were aged 36-80 and 36(57.1%) patients were male. Mean preoperative BMI was 30.91(sd5.11,range21.15–43.93). Mean operating time was 80.81(37.34,20-240)minutes. In 13(20.6%) patients multiple hernia defects were identified. A good degree of fascial closure was achieved in all patients using a median of 3(IQR 2.0-3.5)knots. Median mesh-fixation time was 286(159.5-428.0)seconds and a mean 25.24(5.49,14-41)tacks/patient were used. Median length of hospital stay was 3.5(2.0–6.0)days. Patients were asked “Please indicate on this scale [VAS 0–10] the pain that you currently experience from your incisional hernia during activity?”. Median responses for Day0/pre-op, Day1, Day6, Day30 and Day365 were 4.5, 8.0, 6.0, 3.0 and 1.5 respectively. At one year, 7(11%) patients had experienced hernia recurrence and 33(52%) post-operative seroma. Conclusions Target recruitment was not possible owing to COVID-19. The Manchester Technique has comparable recurrence rates. Reported pain increases post-operatively but is reduced at post-operative day30 and day365.

O39 ASSOCIATION OF DIFFERENT MESH AND MESH FIXATION COMBINATIONS WITH REOPERATION RISK AFTER LAPAROSCOPIC GROIN HERNIA SURGERY. A SWEDISH HERNIA REGISTRY STUDY OF 25,190 TEP AND TAPP REPAIRS

Aim The HerniaSurge guidelines concerning mesh and fixation options in laparoscopic totally extraperitoneal (TEP) and transabdominal preperitoneal (TAPP) groin hernia repair are based on studies focusing on either mesh or fixation. We hypothesized that the value of such recommendations is limited by lacking knowledge on how mesh and fixation interact. The present registry-based nationwide cohort study compared different mesh/fixation combinations regarding relative risks for reoperation after TEP and TAPP. Material and Methods All TEP and TAPP with standard polypropylene (StdPPM) or lightweight (LWM) flat meshes, combined with either tacks, fibrin glue, or no fixation, registered in the Swedish Hernia Registry 2005-2017 were included. Endpoint was reoperation due to recurrence as of December 31, 2018. Multivariable Cox regression rendered relative risk differences between the exposures, expressed as hazard ratios (HR) with 95% confidence intervals (CI). Results Of 25 190 repairs, 924 (3.7%) were later reoperated for recurrence. The lowest, mutually equivalent, reoperation risks were associated with StdPPM without fixation (HR 1), StdPPM with metal tacks (HR 0.8, CI 0.4-1.4), StdPPM with fibrin glue (HR 1.1, CI 0.7-1.6), and LWM with fibrin glue (HR 1.2, CI 0.97-1.6). LWM correlated otherwise with increased risk, whether without fixation (HR 2.0, CI 1.6-2.6), or affixed with metal (HR 1.7, CI 1.1-2.7), or absorbable tacks (HR 2.4, CI 1.8-3.1). Conclusions With StdPPM, fixation seems not to improve outcomes, despite being costlier. Thus, for this mesh category, we recommend non-fixation. With LWM, we recommend fibrin glue fixation, which was the only LWM alternative on par with non-affixed StdPPM.

O41 PREDICTORS OF LOW QUALITY AFTER OPEN INGUINAL HERNIA REPAIR USING THE EURAHS-QOL SCORE: PROSPECTIVE MULTICENTRIC COHORT STUDY

Aim Evidence about factors influencing quality of life after inguinal hernia surgery is scarce. This study aimed to identify predictors of low Quality of Life (QoL) after open inguinal hernia repair, to guide practice and inform patients at high risk. Material and Methods Prospective multicentric cohort study including consecutive patients undergoing elective open inguinal hernia repair in Portuguese hospitals (October-December 2019). The primary outcome was Quality of Life at 3 months after surgery, using the EuraHS-QoL score (higher score correlates with lower QoL). Low QoL was defined as the higher EuraHS-QoL score tertile and multivariate logistic regression was used to identify predictors. Results 893 patients were included from 33 hospitals. The majority were men (89.9% [800/891]), had unilateral hernias 88.7% (774/872) and the most common surgical technique was Lichtenstein’s repair (52.9% [472/893]). The median QoL score was 24 (IQR 10-40) before surgery and 2 (IQR 0-10) at 3 months after surgery, showing significant improvement (p < 0.001). After adjustment, low QoL at 3 months was associated with low preoperative QoL (OR 1.76, 95% CI 1.21-2.57, p = 0.003), non-absorbable mesh fixation (OR 1.64, 95% CI 1.12-2.41, p = 0.011), severe immediate postoperative pain (OR 2.90, 95% CI 1.66-5.11, p < 0.001) and minor postoperative complications (OR 2.23, 95% CI 1.30-3.84, p = 0.004). Conclusions This study supports the use of the EuraHS-QoL score preoperatively to inform consent. Although significant improvement in QoL is expected after surgery, high scores before surgery are associated with low postoperative QoL. Caution should be taken with non-absorbable mesh fixation and immediate postoperative pain control should be optimised.

P044 ATRAUMATIC AND CONSISTENT HERNIA MESH FIXATION: PERFORMANCE AND SAFETY IN A LAPAROSCOPIC IPOM PORCINE MODEL

Aim Demonstrate the performance and safety of TISSIUM on-demand activated adhesive for atraumatic hernia mesh fixation in a laparoscopic IPOM porcine model. Material and Methods Full thickness 4 cm in diameter excisional abdominal defects (n = 14) were created in pig (n = 8). The defects were repaired through laparoscopic intraperitoneal mesh placement using commercial composite meshes fixed with TISSIUM adhesive (n = 8) or resorbable tacks (n = 6). The animals were sacrificed after 28 and 90 days. An independent pathologist evaluated abdominal adhesion, mesh shrinkage, local tissue tolerance and tissue ingrowth through histological analysis (H&E and Movat Pentacrome) at sacrifice. Fixation strength of the explanted abdominal walls was also assessed via burst-ball. Results No adverse events were observed at implantation or during the survival period. All the meshes were in place at sacrifice. Mesh shrinkage and abdominal adhesion scores were similar between the two groups. Histological analysis of the mesh demonstrated equivalent quality of tissue ingrowth and excellent local tissue tolerance with minimal/mild foreign body response and mononuclear cells inflammation. The repair strength, evaluated through a burst ball method 90 days after implantation, showed no significant difference between the TISSIUM adhesive and tacks. Usability is currently being evaluated in clinically relevant models. Conclusions In this preclinical study the TISSIUM adhesive demonstrated similar fixation strength and quality of repair when compared to commercial tacks. This technology has the potential to impact hernia procedures standardization and reduce pain often associated with current fixation technologies.

P049 SAFETY AND EFFICACY OF ABSORBABLE AND NON-ABSORBABLE FIXATION SYSTEMS FOR INTRAPERITONEAL MESH FIXATION: AN EXPERIMENTAL STUDY IN SWINE

Aim Choice of the best fixation system in terms of safety and effectiveness for intraperitoneal mesh placement in hernia surgery remains controversial. The aim of this study was to compare the performance of four fixation systems in a swine model of intraperitoneal mesh fixation. Material and Methods Fourteen Landrace swine were utilized and the experiment included two stages. Initially, four pieces of polypropylene mesh with hydrogel barrier coating1 were fixed intraperitoneally to reinforce 4 small full thickness abdominal wall defects created with diathermy. Each mesh was anchored with a different tack device between titanium2, steel3 or absorbable (4,5) fasteners. The second stage took place after 60 days and included euthanasia, laparoscopy, and laparotomy. The primary endpoint was to compare the peel strength of the compound tack/mesh from the abdominal wall. Secondary parameters were the extent and quality of visceral adhesions to the mesh, the degree of mesh shrinkage and the histological response around the tacks. Results Thirteen out of 14 animals survived the experiment and 10 were included in the final analysis. Steel tacks had higher peel strength when compared to titanium and absorbable fasteners. No significant differences were noted regarding the secondary endpoints. Conclusions Steel fasteners provided higher peel strength that the other devices in this swine model of intraperitoneal mesh fixation. Our findings generate the hypothesis that this type of fixation may be superior in a clinical setting. Clinical trials with long-term follow-up are required to assess the safety and efficacy of mesh fixation systems in hernia surgery.

P080 ROUTINE ELECTIVE ILIOHYPOGASTRIC NEURECTOMY IN LICHTENSTEIN INGUINAL HERNIA REPAIR

Aim Chronic postherniorraphy pain occurs in 8-25% of patients undergoing groin hernioplasty with mesh insertion. The most common cause for inguinodynia is neuropathy resulting from nerve damage or entrapment during mesh fixation. With wide mesh insertion there is often a conflict between upper prosthesis margin and an iliohypogastric nerve. The aim of this study is to present a routine elective iliohypogastric neurectomy in Lichtenstein groin hernia repair for prevention of chronic inguinodynia. Material and Methods Between 2018 and 2020, 398 patients were admitted for open inguinal hernia repair. 218 patients underwent a Lichtenstein repair with transection of iliohypogastric nerve before implantation of 10x14 polypropylene mesh (IH group). In the control group of 180 patients all nerves were spared (C group). Follow-up was conducted on 1 POD,1 month, and 1 year after surgery. Results 1 month after a surgery a pain was reported in 24 (11%) patients in IH group (2.9% severe; 8.1% moderate; 89% no pain), and 48 (26.7%) patients in C group (3.9% severe; 22.8% moderate; 73.3% no pain). 1 year after a surgery a persistent pain was reported in 1 (0.4%) patient in IH group, and in 5 (2.8%) patients in C group. An incidence of inguinodynia was significantly lower after iliohypogastric neurectomy (0.5% vs. 2.8%; p < 0.001). Conclusions Routine neurectomy of iliohypogastric nerve appears to be an effective technique in chronic inguinodynia after open mech repair for inguinal hernias. Iliohypogastric nerve resection allows to place a flat synthetic mesh with wide coverage of myopectineal orifice with no need for additional mesh trimming.