Characterization of host response,resorption, and strength properties,and performance in the presence of bacteria for fully absorbable biomaterials for soft tissue repair

Purpose

The objective was to evaluate the host response, resorption, and strength properties, and to assess the performance in the presence of bacteria for Phasix? Mesh (Phasix?) and Gore^® Bio-A^® Tissue Reinforcement (Bio-A^®) in preclinical models.

Methods

In a rat model, one mesh (2 × 2 cm) was implanted subcutaneously in n = 60 rats. Animals were euthanized after 2, 4, 8, 12, 16, or 24 weeks (n = 5/mesh/time point), and implant sites were assessed for host inflammatory response and overall fibrotic repair thickness. In a rabbit model, meshes (3.8 cm diameter) were bilaterally implanted in subcutaneous pockets in n = 20 rabbits (n = 10 rabbits/mesh) and inoculated with 10⁸ CFU clinically isolated methicillin-resistant Staphylococcus aureus (MRSA). One mesh type was implanted per animal. Animals were euthanized after 7 days, and implants were assessed for abscess formation, bacterial colonization, and mechanical strength.

Results

In the rat study, Phasix? and Bio-A^® exhibited similar biocompatibility, although Bio-A^® demonstrated a significantly greater inflammatory response at 4 weeks compared to Phasix? (p < 0.01). Morphometric analysis demonstrated rapid resorption of Bio-A^® implants with initially thicker repair sites at 2, 4, 8, and 12 weeks (p < 0.0001), which transitioned to significantly thinner sites compared to Phasix? at 16 and 24 weeks (p < 0.0001). In the rabbit bacterial inoculation study, Phasix? exhibited significantly lower abscess score (p < 0.001) and bacterial colonization (p < 0.01), with significantly greater mechanical strength than Bio-A^® (p < 0.001).

Conclusions

Host response, resorption, repair thickness, strength, and bacterial colonization suggest a more stable and favorable outcome for monofilament, macroporous devices such as Phasix? relative to multifilament, microporous devices such as Bio-A^® over time.

     

Comparative analysis of histopathologic responses to implanted porcine biologic meshes

Objectives

Biologic mesh (BM) prostheses are increasingly utilized for hernia repairs. Modern BMs are not only derived from different tissue sources, but also undergo various proprietary processing steps—factors that likely impact host tissue responses and mesh performance. We aimed to compare histopathologic responses to various BMs after implantation in a mouse model.

Materials and methods

Five-mm samples of non-crosslinked [Strattice (ST)], and intentionally crosslinked [CollaMend (CM), Permacol (PC)] porcine-derived biologic meshes were implanted subcutaneously in C57BL/6 mice. 1, 4, 8, and 12 weeks post-implantation, meshes were assessed for inflammation, foreign body reaction (FBR), neocellularization, and collagen deposition using H&E and trichrome stains.

Results

All meshes induced early polymorphonuclear cell infiltration (highest in CM; lowest in ST) that resolved by 4 weeks. ST was associated with extensive macrophage presence at 12 weeks. Foreign body response was not seen in the ST group, but was present abundantly in the CM and PC groups, highest at 8 weeks. New peripheral collagen deposition was seen only in the ST group at 12 weeks. Collagen organization was highest in the ST group as well. Both CM and PC groups were associated with fibrous encapsulation and no evidence of integration or remodeling.

Conclusions

Inflammation appears to be a common component of integration of all biologic meshes studied. Pronounced inflammatory responses as well as profound FBR likely lead to observed encapsulation and poor host integration of the crosslinked BMs. Overall, ST was associated with the lowest foreign body response and the highest degree of new collagen deposition and organization. These features may be key predictors for improved mesh performance during hernia repair.     

The use of Vicryl mesh in a porcine model to assess its safety as an adjunct to posterior fascial closure during retromuscular mesh placement

Background

Posterior component separation has become a common approach to complex abdominal wall reconstructions. This technique includes creation of an extraperitoneal retromuscular space for subsequent large synthetic mesh reinforcement. In certain cases, when complete restoration of “posterior” layer is precluded by significant tissue loss/damage, one proposed strategy is to replace the posterior fascia with an absorbable synthetic polyglactin (Vicryl) mesh. However, the safety of this strategy to prevent mesh-related visceral complication is unknown. Herein, we aimed to characterize mesh-viscera adhesion profiles and host tissue response of synthetic mesh either exposed directly to the viscera, or protected with Vicryl mesh.

Methods

Using adult Yorkshire pigs, 5 × 5 cm pieces of mesh were secured to the intact peritoneum in each of the four quadrants (n = 6 pigs, 24 mesh samples). The study groups were Vicryl (V), Marlex (M), Softmesh (S), Marlex + Vicryl construct (MV), Softmesh + Vicryl construct (SV). The self-made composite meshes were then implanted with the Vicryl side facing the exposed viscera. The pigs were survived for 60 days. At necropsy, grossly, the extent and tenacity of visceral adhesions were evaluated using established scales. Histologically, all specimens for fibrous encapsulation on the visceral surface of the mesh were reviewed by an experienced pathologist blind to meshes used.

Results

At necropsy, all Vicryl meshes were completely resorbed. The mean adhesion and tenacity scores for M and MV were 1.8 and 1.1 (P > 0.05), 2.0 and 1.5 (P > 0.05), respectively; while the mean adhesion extent scores and tenacity scores for S and SV were 2.0 and 1.2 (P > 0.05), 2.0 and 1.7 (P > 0.05). No significant difference in adhesion extent and tenacity was observed between Synthetic and Vicryl composite mesh groups. Histologically, Marlex + Vicryl mesh and Softmesh + Vicryl mesh constructs had thicker fibrous capsules than the corresponding unprotected Marlex and Soft mesh implants. Furthermore, visceral adhesions in the composite groups were noted to be to the fibrous capsule and not synthetic mesh itself.

Conclusion

Utilization of the absorbable polyglactin (Vicryl) mesh as a separating layer between a synthetic mesh and intestines, did not reduce adhesions across various mesh types and composites. Histologically, however, a thick fibrous capsule replaced the Vicryl mesh and may be an important layer to prevent intestinal erosion into retromuscular synthetic meshes.

     

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.

     

Postoperative changes after surgical mesh hernia repair: a pitfall in interpretation of 18F-FDG PET-CT

Objective

A number of case reports have demonstrated FDG uptake around mesh prostheses after hernia repair surgery. This study characterizes FDG PET-CT findings after hernia repair with synthetic mesh in a series of cancer patients.

Materials and methods

FDG PET-CT studies were reviewed for increased FDG uptake consistent with CT appearances of post-surgical hernia repair in cancer patients. The findings were correlated with clinical data and follow-up studies.

Results

53 PET-CT studies in 22 patients (18 males, 31–79 years) were identified. Surgery for repair of inguinal (n = 14), ventral (n = 5) or umbilical (n = 3) hernia was performed, 4–204 months prior to PET-CT. FDG avidity was focal or linear in the region of the anterior abdominal or pelvic wall (mean SUV max 4.0 ± 2.3). Corresponding nonspecific CT findings included soft tissue thickening (n = 18), fat infiltration (n = 20) and fluid collection (n = 19) in the region of the omentum, adjacent to or in the inner abdominal or pelvic wall at the surgical site. Linear hyper-dense structures (n = 9) or metallic clips (n = 8) seen on CT suggested benign postoperative changes. In 10/12 (83.3%) patients with repeat PET-CT, FDG uptake remained unchanged, one showed more diffuse uptake and another showed reduced uptake on follow-up. There was neither significant change in CT appearance at the surgical site in these 12 patients, nor in 3 additional patients with only CT follow-up. Another 3 patients had previous CT demonstrating hernia at the same location.

Conclusion

With increasing use of synthetic mesh, awareness of variations in FDG PET-CT appearance is important to avoid false interpretation in cancer patients.

     

Experimental study of inflammatory response and collagen morphometry with different types of meshes

Purpose

To compare an inflammation score and collagen morphometry after incisional hernia repair with four different meshes at two time points.

Methods

Four types of mesh were used to repair an abdominal wall incisional defect in Wistar rats: high-density polypropylene (HW/PP); low-density polypropylene (LW/PP); polypropylene mesh encapsulated with polydioxanone coated with oxidized cellulose (PP/CE); and expanded polytetrafluoroethylene (ePTFE). An inflammation score based on histological analysis and collagen morphometry was performed after 7 and 28 days after operation (POD).

Results

Compared to LW/PP group at 7 POD, HW/PP group had lower (p = 0.014) and PP/CE group had higher inflammation scores (p = 0.001). At 28 POD, higher scores were seen in all the other groups compared to the LW/PP group (HW/PP, p = 0.046; PP/CE, p < 0.001; ePTFE, p = 0.027). Comparing groups individually at 7 and 28 PODs, all demonstrated lower inflammation score values at 28 POD (HW/PP, p < 0.001; LW/PP, p < 0.001; PP/CE, p = 0.002; ePTFE, p = 0.001). At 7 POD, higher amounts of collagen were detected in ePTFE compared to HW/PP (p < 0.001) and LW/PP (p = 0.004) and in PPCE group compared to HW/PP (p = 0.022). At 28 POD, no statistically significant difference was found. Comparing groups individually at 7 and 28 PODs, HW/PP and LW/PP showed larger amounts of collagen at the 28th POD, without any statistically significant differences for the PP/CE and ePTFE groups.

Conclusions

Inflammation scores decreased in all groups at 28 POD. Collagen deposition was higher for non-composite meshes at 28 POD.

     

Lower exposure rates of partially absorbable mesh compared to nonabsorbable mesh for cystocele treatment: 3-year follow-up of a prospective randomized trial

Introduction and hypothesis

In surgery for pelvic organ prolapse (POP) the use of alloplastic meshes has become common. Among possible complications, mesh exposure is the most frequent problem. It is hypothesized that exposure rates are correlated to mesh weight and the amount of foreign material. Therefore, we conducted a prospective open-label randomized multicenter trial comparing a conventional polypropylene mesh (PP) with a partially absorbable polypropylene mesh (PA) for cystocele treatment.

Methods

A total of 200 patients with POP > stage I were randomized either to a conventional or a partially absorbable mesh. Exposure rates were observed after 3, 12, and 36 months and correlated to mesh material, patient characteristics, intraoperative data, and treatment centers. Furthermore, management of mesh exposure, satisfaction with surgery, and postoperative pain were evaluated.

Results

At all follow-up intervals mesh exposure rate was smaller in the group of the partially absorbable mesh (3 months PP 11.3 % vs PA 3.2 %, p?=?0.0492; 12 months 6.6 % vs 6.3 %; 36 months 7.5 % vs 3.4 %). Over the course of time, mesh exposure was observed in 27 patients, with surgical intervention necessary in 11 patients. The rate of recurrent POP was higher (p?>?0.05) in patients with the partially absorbable mesh. The majority of patients were fully satisfied with the operation (52.8 %) and had no pelvic floor pain (67.5 %).

Conclusion

In this prospective, randomized trial with a long-term follow-up there was a low exposure rate in both treatment groups with a trend toward fewer exposures in the group of the partially absorbable mesh.     

A mechanism of mesh-related post-herniorrhaphy neuralgia

Purpose

The objective is to compare nerve densities in explanted polypropylene meshes in patients with or without chronic pain. Pain has supplanted recurrences as a complication of hernia surgery. The increased incidence of pain mirrors a parallel increase in the use of polypropylene meshes. Neither triple neurectomy nor careful nerve preservation has brought relief. Perhaps because we have forgotten that nerves, in response to some evolutionary mechanism, tend to regenerate, undergo changes imposed by prosthetic elements and architecture, mimicking entrapment and compartment syndromes.

Methods

A total of 33 hernia meshes have been analyzed: 17 excised due to severe pain, two for combined pain and recurrence, 14 sampled during revision for recurrence without pain. Each mesh had standardized sampling for histology and the nerves were highlighted by S100 stain. Nerve densities were assessed within the mesh spaces and in tissue outside the mesh.

Results

The density of nerves present in the standardized mesh samples of patients complaining of pain was much more elevated than in the mesh of those patients who had a recurrence but no pain. The difference was statistically significant (p < 0.001). Excluding two patients who had both pain and recurrence, the difference was even more marked (p < 0.0001).

Conclusions

Re-innervation and neo-innervation are known to take place following hernia repairs in indigenous tissue as well as through polypropylene meshes. However, when pain is an overriding issue dictating mesh explant, the degree of mesh innervation is significantly higher when compared to mesh excised for recurrence. That increase has been confirmed statistically.

     

A single-centre experience of relaparoscopy in complications of laparoscopic inguinal hernia repair-feasibility and outcomes

Background

Management of complications of laparoscopic inguinal hernia repair remains challenging as well as debatable. Relaparoscopy in management of these complications is relatively newer concept. We tried to analyse the feasibility of relaparoscopy (transabdominal preperitoneal approach) in management of complications of laparoscopic inguinal hernia repair.

Materials and methods

The study group included 61 patients (referral cases) from a prospectively maintained database of previous laparoscopic inguinal hernia surgery with majority of the patients of recurrence (n = 39). Other complications were mesh infections (n = 15), pubic osteitis (n = 3), migration of mesh into adjacent viscera (n = 3) and meralgia paresthetica (n = 1). All patients underwent transabdominal preperitoneal approach (TAPP) between January 2007 and December 2013.

Results and outcome

Most of the patients had previous TEP repair (n = 49) with variable complications detected in the range of 9 days to 38 months. Small-sized mesh (n = 12) and rolled up mesh (n = 10) were the causes of recurrence in 57 % cases. Mycobacterium tuberculosis (40 %) and mixed bacterial infections (33 %) strains were detected in the infected mesh. Pubic osteitis and meralgia paresthetica were tackers induced. All patients dealt with TAPP approach. Recurrent hernia cases underwent mesh placement and infected mesh was removed in mesh infection. Tackers were removed in cases of osteitis pubis and meralgia paraesthesia. Median operative time was 62 min (42–126 min) and hospital stay 3 days (2–13 days). The relaparoscopy was accomplished in 95.1 % of cases with no major intraoperative complications and minimal postoperative morbidity.

Conclusion

Relaparoscopy through TAPP approach remains safe and feasible option to deal with primary laparoscopic hernia repair complications. Surgical techniques during primary laparoscopic repair are important cause for aforementioned complications. Though, surgical expertize remains warranted for relaparoscopy.

     

Rail or roll: a new,convenient and safe way to position self-gripping meshes in open inguinal hernia repair

Purpose

In open inguinal hernia repair self-gripping meshes are currently commonly employed. Assumed benefits are saving of time, ease of handling and omission of fixation. Self-gripping meshes are, however, not as easy to handle and position as commonly stated. We describe a newly developed way of intra-operative mesh preparation and implantation and compare it to the conventional technique of insertion of self-gripping meshes.

Methods

A two-armed, randomized trial with 64 patients was performed. For implantation of the self-gripping, light weight and partially absorbable mesh we used either a newly described rolling technique (group 1: n = 32) or the conventional way of insertion (group 2: n = 32). Primary endpoints of the study were feasibility with regard to actual implantation time and surgeons’ satisfaction with the methods. Secondary endpoints were total operating time, length of hospital stay, postoperative pain, duration of pain medication intake and postoperative morbidity. In addition all patients were prospectively followed up according to the Hernia Med® registry’s standards.

Results

Implantation time (seconds) 140 ± 74 vs. 187 ± 84, p = 0.008, duration of pain medication intake (days) 3.6 ± 2.8 vs. 4.8 ± 2.6; p = 0.046 and postoperative morbidity 2 (6%) vs. 8 (25%) was significantly beneficial in group 1 (rolling technique) compared to group 2 (conventional method). Blinded questionnaire revealed that rolling the mesh is generally easier with less repositioning maneuvers than conventional placement. Neither overall procedure time, length of stay nor postoperative pain scores differed significantly between groups.

Conclusion

The newly introduced rolling technique for the actual placement of self-gripping meshes in open inguinal hernia repair is technically less demanding and therefore significantly faster when compared to the conventional way of insertion of the same product. In addition the rolling technique has shown to be safe for the patients and to also provide higher surgeons’ satisfaction.

     

In vitro assessment of an antibacterial quaternary ammonium-based polymer loaded with chlorhexidine for the coating of polypropylene prosthetic meshes

Purpose

This study assesses the use of an absorbable polymer loaded with chlorhexidine (CHX) as an antibacterial coating for polypropylene (PP) meshes employed in hernia repair.

Methods

The polymer N,N-dimethyl-N-benzyl-N-(2-methacryloyloxyethyl) ammonium bromide was loaded with CHX (1 % w/w). Fragments (1 cm²) of Optilene^® Mesh Elastic were coated either with the unloaded (POL) or CHX-loaded polymer (POL–CHX). Uncoated fragments (PP) served as controls. The release kinetics of the POL–CHX coating was monitored by HPLC. Sterile fragments were placed on agar plates previously contaminated with 10⁶ CFU of Staphylococcus aureus (Sa) ATCC25923, Staphylococcus epidermidis (Se) ATCC12228, or Escherichia coli (Ec) ATCC25922 and incubated at 37 °C for 1/2/7 days. At each time point, inhibition halos were measured and bacterial adhesion to the meshes quantified by sonication and scanning electron microscopy. Coating cytotoxic effects were examined on cultured fibroblasts.

Results

The polymer coating gradually released CHX over 3 days. Inhibition halos were produced only around the POL–CHX-coated meshes and these were significantly smaller for Ec than Sa or Se (p < 0.01). While POL–CHX prevented bacterial adhesion to the mesh, the reduced bacterial yields over time were observed for the POL-coated versus control PP meshes (p < 0.001). By day 7, only Ec remained attached to the surface of control meshes. The POL coating was not cytotoxic, yet POL–CHX reduced the viability of cultured fibroblasts.

Conclusions

When loaded with the antiseptic CHX, this quaternary ammonium-based polymer coating released its contents in a controlled manner indicating its potential prophylactic use to reduce the risk of infection following PP mesh implantation.

     

Major Complex Abdominal Wall Repair in Contaminated Fields with Use of a Non-cross-linked Biologic Mesh: A Dual-Institutional Experience

Background

Data on the use of biologic mesh in abdominal wall repair in complex cases remain sparse. Aim of this study was to evaluate a non-cross-linked porcine acellular dermal matrix for repair of complex contaminated abdominal wall defects.

Methods

Retrospective observational cohort study of consecutive patients undergoing abdominal wall repair with use of Strattice? Reconstructive Tissue Matrix (LifeCell Corporation, Oxford, UK) between January 2011 and February 2015 at two National Intestinal Failure Units.

Results

Eighty patients were identified. Indications for abdominal wall repair included enterocutaneous fistula takedown (n = 50), infected synthetic mesh removal (n = 9), restoration of continuity or creation of a stoma with concomitant ventral hernia repair (n = 12), and others (n = 9). The median defect area was 143.0 cm² (interquartile range or IQR 70.0–256.0 cm²). All had a grade III or IV hernia. Component separation technique (CST) was performed in 54 patients (68%). Complete fascial closure was not possible despite CST and biologic mesh-assisted traction (bridged repair) in 20 patients (25%). In-hospital mortality was 1%. Thirty-six patients (45%) developed a wound infection. None required mesh removal. Of 76 patients with a median clinical follow-up of 7 months (IQR 4–15) available for analysis, 10 patients (13%) developed a hernia recurrence, of whom 3 had undergone bridged repairs. Seven patients developed a postoperative (recurrent) fistula (9%).

Conclusion

Repair of challenging and contaminated abdominal wall defects can be done effectively with non-cross-linked biologic mesh and component separation technique without the need for mesh removal despite wound infections.

     

Anatomical and functional changes to the pelvic floor after robotic versus laparoscopic ventral rectopexy: a randomised study

Introduction and hypothesis

To compare the effect of laparoscopic and robot-assisted ventral rectopexy for posterior compartment procidentia on the pelvic floor anatomy and function.

Methods

A prospective randomised single-centre study was carried out of 29 female patients, who underwent robot-assisted or laparoscopic ventral mesh rectopexy for external or internal rectal prolapse with symptoms of obstructive defecation and/or faecal incontinence. Anatomical changes were measured by Pelvic Organ Prolapse Quantification (POP-Q) and magnetic resonance defecography. Functional changes were evaluated using symptom questionnaires before and 3 months after surgery.

Results

After rectopexy, changes in POP-Q measurements were statistically significant for points Ap, Bp, C, D and Ba. The descent of the anorectum and cervix/vaginal cuff during straining were significantly reduced with regard to the reference line (mean, ?10.4?±?14.9 mm, p?=?0.001) and (?13.3?±?18.1 mm, p?<?0.001) respectively. Pelvic organ mobility (POM) was reduced statistically significantly for the posterior (mean, ?16.6?±?20.8 mm, p?<?0.001) and apical compartments (mean, ?13.1?±?14.8, p?<?0.001). The PFDI-20, PFIQ-7 and PISQ-12 questionnaires showed statistically significant improvement of symptoms and sexual function. No significant differences were observed between the robot-assisted and laparoscopic techniques in terms of anatomical or functional parameters.

Conclusion

Ventral mesh recto-colpo-sacropexy effectively corrects the anatomy of the posterior compartment, elevates the vaginal apex and reduces pelvic organ mobility of the posterior and middle compartments. The robot-assisted and laparoscopic techniques had similar anatomical and functional outcomes.

     

Randomized Clinical Trial Comparing Cyanoacrylate Glue Versus Suture Fixation in Lichtenstein Hernia Repair: 7-Year Outcome Analysis

Background

Lichtenstein hernioplasty has relatively low recurrence rate, but chronic inguinal pain may cause harm to the patient. The aim of our study was to compare long-term results of cyanoacrylate glue versus absorbable sutures for mesh fixation in Lichtenstein hernioplasty.

Methods

Lichtenstein hernioplasty (n = 302) was performed under local anesthesia in three hospitals. The patients were randomized to receive either 1 ml of butyl-2-cyanoacrylate tissue glue (Glubran^®; 151 hernias) or absorbable polyglycolic acid sutures (Dexon^®; 151 hernias) for mesh fixation (Optilene^® mesh). Short-term results were published previously. Chronic groin pain, foreign body sensation, use of analgesics, recurrence and re-operations were analyzed 7 years after surgery.

Results

We reached 236 patients (78%) to present study. In the glue group (n = 115), there were five (4.3%) and in the suture group (n = 121) three (2.5%) recurrent hernias (p = 0.491). The prevalence of chronic pain (NRS ≥ 3) in the patients without re-operations was similar in two groups: 15/118 (13%) and 13/111 (12%), respectively (p = 0.843). There were no significant differences in the foreign body sensation (8/14, p = 0.267) or in the need of analgesics (2/2, p = 1.00) between the two study groups.

Conclusion

Both cyanoacrylate glue and mesh fixation with absorbable sutures were equal in terms of chronic pain and rate of recurrences in Lichtenstein hernioplasty after 7-year follow-up.

Trial registration number

NCT00659542.

     

Evaluation of a novel permanent capped helical coil fastener in a porcine model of laparoscopic ventral hernia repair

Background

Existing permanent helical coil fasteners, although commonly employed for mesh fixation during laparoscopic hernia repair, are associated with peritoneal tissue attachment formation and resultant visceral complications. We evaluated attachment formation, fastener engagement, and mesh/tissue integration associated with laparoscopic fixation using a novel permanent capped helical coil fastener (HC-Capped) compared to permanent non-capped helical coil fasteners (HC-Non-Capped) in a porcine model.

Methods

Twelve female pigs underwent bilateral laparoscopic intraperitoneal fixation of Composix? L/P Mesh (10 × 15 cm oval) with HC-Capped or HC-Non-Capped fasteners. Thirty-two fasteners were used to secure each mesh utilizing a “double-crown” technique. Laparoscopy at 30 days was used to evaluate the presence and area coverage of attachments (Diamond Score) and percentage of engaged fasteners. At 90 days, following necropsy, each mesh was evaluated for the presence, percentage, and tenacity (Butler Score) of attachments and fastener engagement. Samples were biomechanically evaluated to assess tissue integration via T-peel testing.

Results

HC-Capped fasteners demonstrated a significantly lower attachment area score compared to the HC-Non-Capped group at 30 days (0.92 ± 0.26 vs. 2.50 ± 0.29/3.00, p = 0.002) and 90 days (0.60 ± 0.22 vs. 2.08 ± 0.29/3.00, p = 0.004). At 90 days, the HC-Capped group evidenced significantly lower attachment tenacity score (1.00 ± 0.37 vs. 2.75 ± 0.33/4.00, p = 0.013). Furthermore, at 30 and 90 days, a significantly greater percentage of HC-Capped fasteners remained properly engaged (30 days: 99.7 % vs. 86.5 %, p < 0.001 and 90 days: 99.4 % vs. 74.5 %, p = 0.001). T-peel biomechanical testing demonstrated significantly greater mesh/tissue integration for HC-Capped group (2.16 ± 0.24 vs. 1.16 ± 0.29 N/cm, p = 0.038).

Conclusions

In a porcine model, HC-Capped fasteners demonstrated significantly less attachment coverage and tenacity in the early postoperative period. Furthermore, the HC-Capped cohort evidenced significantly greater percentage of properly engaged fasteners and greater mesh/tissue integration. Data suggest that shielding exposed fastener points on the visceral mesh surface with polymer caps may reduce attachment formation and aid in mesh fixation and integration.

     

Impacts of Supervised Exercise Training in Addition to Interdisciplinary Lifestyle Management in Subjects Awaiting Bariatric Surgery: a Randomized Controlled Study

Background

Experts recommend physical activity (PA) to optimize bariatric surgery (BS) results. However, evidence on the effect of PA before BS is missing. The aim of this study was to assess the impact of adding a Pre-Surgical Exercise Training (PreSET) to an interdisciplinary lifestyle intervention on physical fitness, quality of life, PA barriers, and anthropometric parameters of subjects awaiting BS.

Methods

Thirty candidates for BS (43.2?±?9.2 years, 47.5?±?8.1 kg/m²) have been randomized in two groups: one group following the PreSET (endurance and strength training) and another receiving usual care. Before and after 12 weeks, we assessed physical fitness with a battery of tests (symptom-limited exercise test, 6-min walk test (6MWT), sit-to-stand test, half-squat test, and arm curl test), quality of life with the laval questionnaire, and PA barriers with the physical exercise belief questionnaire.

Results

One control group subject abandoned the study. Subjects in the PreSET group participated in 60.0 % of the supervised exercise sessions proposed. Results showed significant improvements in the 6MWT (17.4?±?27.2 vs. ?16.4?±?42.4 m; p?=?0.03), half-squat test (17.1?±?17.9 vs. ?0.9?±?14.5 s; p?=?0.05), arm curl repetitions (4.8?±?2.3 vs. 1.0?±?4.1; p?=?0.01), social interaction score (10.7?±?12.5 vs. ?2.1?±?11.0 %; p?=?0.02), and embarrassment (?15.6?±?10.2 vs. ?3.1?±?17.8 %; p?=?0.02) in completers (n?=?8) compared to the non-completers (n?=?21). No significant difference between groups in BMI and other outcomes studied was observed after the intervention.

Conclusions

Adding a PreSET to an individual lifestyle counselling intervention improved physical fitness, social interactions, and embarrassment. Post-surgery data would be interesting to confirm these benefits on the long term.

     

Early biocompatibility of crosslinked and non-crosslinked biologic meshes in a porcine model of ventral hernia repair

Purpose

Biologic meshes have unique physical properties as a result of manufacturing techniques such as decellularization, crosslinking, and sterilization. The purpose of this study is to directly compare the biocompatibility profiles of five different biologic meshes, AlloDerm^® (non-crosslinked human dermal matrix), PeriGuard^® (crosslinked bovine pericardium), Permacol^® (crosslinked porcine dermal matrix), Strattice^® (non-crosslinked porcine dermal matrix), and Veritas^® (non-crosslinked bovine pericardium), using a porcine model of ventral hernia repair.

Methods

Full-thickness fascial defects were created in 20 Yucatan minipigs and repaired with the retromuscular placement of biologic mesh 3 weeks later. Animals were euthanized at 1 month and the repair sites were subjected to tensile testing and histologic analysis. Samples of unimplanted (de novo) meshes and native porcine abdominal wall were also analyzed for their mechanical properties.

Results

There were no significant differences in the biomechanical characteristics between any of the mesh-repaired sites at 1 month postimplantation or between the native porcine abdominal wall without implanted mesh and the mesh-repaired sites (P > 0.05 for all comparisons). Histologically, non-crosslinked materials exhibited greater cellular infiltration, extracellular matrix (ECM) deposition, and neovascularization compared to crosslinked meshes.

Conclusions

While crosslinking differentiates biologic meshes with regard to cellular infiltration, ECM deposition, scaffold degradation, and neovascularization, the integrity and strength of the repair site at 1 month is not significantly impacted by crosslinking or by the de novo strength/stiffness of the mesh.

     

Shoulder periprosthetic joint infection caused by <Emphasis Type="Italic">Propionibacterium acnes</Emphasis>

Background

Propionibacterium acnes is increasingly recognized as an important cause of shoulder periprosthetic joint infection (PJI). We performed a retrospective cohort study of P. acnes shoulder PJI to analyze the clinical, diagnostic, and treatment characteristics.

Methods

Patients diagnosed with shoulder PJI caused by P. acnes were retrospectively analyzed in two university hospitals. Patient data were retrieved through chart review. The outcome was evaluated at patient follow-up visits.

Results

The study included 20 patients with shoulder PJI (median age, 65 years; range, 54–77 years); 75 % were males. The median time from prosthesis implantation to diagnosis of PJI was 34 months (range, 2–60 months). Most PJI (55?%) were diagnosed >24 months after arthroplasty, followed by delayed manifestation 3–24 months after arthroplasty in 30?%. The diagnosis of PJI was preoperatively confirmed in 50?% of patients and suspected in 20 %. Persistent pain was present in 90?%, local signs of inflammation in 60?%, and radiological signs of loosening in 70 % of patients. P. acnes was cultured in joint aspirate in 33?%, periprosthetic tissue in 60?%, and sonication fluid in 89?% of patients. In four patients, coinfection with coagulase-negative staphylococci was found. One-stage prosthesis exchange was performed in four patients (20?%) and two-stage exchange in 15 patients (75?%); in one patient the prosthesis was not re-implanted. After a median follow-up of 26 months (range, 12–47 months), 18 patients (90?%) showed no signs or symptoms of infection.

Conclusion

P. acnes PJI typically manifested several years after implantation. In 30?% of patients, PJI was not suspected before surgery. In patients with persistent pain or prosthesis loosening, low-grade PJI should be excluded, including infection caused by P. acnes.

     

Early Weight Loss as a Predictor of 2-Year Weight Loss and Resolution of Comorbidities After Sleeve Gastrectomy

Background

The objective of this study was to investigate whether early postoperative weight loss predicts weight loss 1 and 2 years after laparoscopic sleeve gastrectomy (LSG) and to determine its effect on the resolution of comorbidities.

Methods

This was a prospective study of patients who underwent LSG at Jordan University Hospital from February 2009 to January 2014.

Results

One hundred ninety patients (mean age 34.0?±?10.8 years; mean preoperative body mass index 46.2?±?7.7 kg/m²) were included in the study. Of these, 146 were followed for 1 year and 73 were followed for 2 years. Thirty patients (20.5 %) had hypertension, 23 (15.8 %) had diabetes, 78 (53.4 %) had hyperlipidemia, 30 (20.5 %) had obstructive sleep apnea, and 50 (34.2 %) had more than one comorbidity. The percentage of excess weight loss (%EWL) was 22.7?±?8.1, 75.1?±?22.8, and 72.6?±?17.5 at 1, 12, and 24 months, respectively. Fifty-five patients (37.7 %) had a 1-year %EWL of ≥80 %, and 29 (39.7 %) had a 2-year %EWL of ≥80 %. Linear regression analysis showed a strong correlation between 1-month %EWL and %EWL at 1 year (r ²?=?0.23, p?<?0.001) and 2 years (r ²?=?0.28, p?<?0.001). Resolution of comorbidities was associated with higher %EWL achieved at 1 year, but early postoperative weight loss did not have a significant effect on comorbidity resolution.

Conclusions

Early postoperative weight loss can be used to identify and target poor responders.

     

Does Presoaking Synthetic Mesh in Antibiotic Solution Reduce Mesh Infections? An Experimental Study

Background

Prosthetic mesh infection is one of the most challenging complications after hernia repair. We evaluate the efficacy of soaking mesh in antibiotics to prevent prosthetic infection in an animal model of clean–contaminated ventral hernia repair (VHR).

Material and Methods

Rats underwent an acute VHR with one of four synthetic meshes (composite multifilament polyester (Parietex PCO), multifilament polyester (Parietex TET), composite monofilament polypropylene (Ventralight), or monofilament polypropylene (SoftMesh)). Prior to implantation, mesh was soaked in saline or 10 mg/ml of vancomycin for 15 min. Following implantation, meshes were contaminated with 10⁴ CFU of methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Thirty days after implantation, mesh samples were cultured and evaluated under scanning electron microscope for biofilm formation.

Results

Presoaking meshes significantly improves bacterial clearance in composite meshes and multifilament polyester mesh. MRSA clearance was as follows for all meshes (saline-soaked vs. vanco-soaked): Parietex PCO (0 vs. 56 %, p?=?0.006), Parietex TET (0 vs. 50 %, p?=?0.01), Ventralight (20 vs. 78 %, p?=?0.012), and SoftMesh (70 vs. 80 %, p?=?0.6). MRSA biofilm formation was consistent with bacterial growth.

Conclusion

Presoaking multifilament and composite mesh in vancomycin solution reduces MRSA bacterial growth. Its implementation may reduce the risk of mesh infection in clean–contaminated cases, although further investigation with human trials should be performed.