Current practices in complex abdominal wall reconstruction in the Americas: need for national guidelines?

BACKGROUND: Component separation (CS) procedures have become an important part of surgeons' armamentarium. However, the exact criteria for training, procedure/mesh choice, as well as patient selection for CS remains undefined. Herein we aimed to identify trends in CS utilization between various cohorts of practicing surgeons. STUDY DESIGN: Members of the Americas Hernia Society were queried using an online survey. Responders were stratified according to their experience, practice profile (private vs academic, general vs hernia surgery), and volume (low (< 10/year) vs high) of CS procedures. We used Chi-squared tests to evaluate significant associations between surgeon characteristics and outcomes. RESULTS: 275 responses with overwhelming male preponderance (88%) were collected. The two most common self-identifiers were "general" (66%) and "hernia" (28%) surgeon. PCS was the most commonly (67%) used type of CS; endoscopic ACS was least common (3%). Low-volume surgeons were more likely to utilize the ACS (p < 0.05). Only 7% of respondents learned PCS during their residency, as compared to 36% that use ACS. 65% felt 0-10 cases was sufficient to become proficient in their preferred technique. 10 cm-wide defect was the most common indication for CS; 23% used it for 5-8 cm defects. Self-identified "hernia" and high-volume surgeons were more likely to use synthetic mesh in the setting of previous wound infections and/or contaminated field (p < 0.05). More general/low-volume surgeons use biologic mesh. Contraindications to elective CS varied widely in the cohort, and 9.5% would repair poorly optimized patients electively. Severe morbid obesity was the most feared comorbidity to preclude CS. CONCLUSION: The use of CS varies widely between surgeons. In this cohort, we discovered that PCS was the most commonly used technique, especially by hernia/high-volume surgeons. There are differences in mesh utilization between high-volume and low-volume surgeons, specifically in contaminated fields. Despite its prevalence, CS training, indications/contraindications, and patient selection must be better defined.

Evaluation of anterior versus posterior component separation for hernia repair in a cadaveric model.

BACKGROUND: Component separation remains an integral step during ventral hernia repair. Although a multitude of techniques are described, anterior component separation (ACS) via external oblique release (EOR) and posterior component separation (PCS) via transversus abdominis muscle release (TAR) are commonly utilized. The extent of myofascial medialization after ACS or PCS has not been well elucidated. We conducted a comparative analysis of ACS versus PCS in an established cadaveric model. METHODS: Fifteen cadavers underwent both ACS via EOR and PCS via TAR. Following midline laparotomy (MLL), baseline myofascial elasticity was measured. Steps for ACS included creation of subcutaneous flaps (SQF), external oblique release (EOR), and retrorectus dissection (RRD). For PCS, steps included retrorectus dissection (RRD), transversus abdominis muscle division (TAD), and retromuscular dissection (RMD). Maximal advancement of anterior rectus fascia (ARF) was measured following application of tension to the fascia as a whole, and separately at upper, middle, and lower segments. Statistical analysis was performed with Mann-Whitney U test. Values are represented as average myofascial medialization in centimeters. RESULTS: Following MLL an average of 5.0 ± 0.9 cm (range 3.4-6.0 cm) of baseline medialization was obtained. Complete ACS provided 8.8 ± 1.2 cm (range 6.3-10.7 cm) of ARF advancement compared to 10.2 ± 1.7 cm (range 7.6-12.7 cm) with PCS, p = 0.046. In the upper and mid-abdomen, we noted increased ARF advancement with PCS versus ACS (8.1 ± 1.4 cm vs. 6.7 ± 1.2 cm and 11.4 ± 1.5 vs. 9.6 ± 1.4 cm, respectively, p = 0.01). Similar levels of ARF advancement were observed in the lower abdomen, 9.1 ± 1.7 cm versus 8.7 ± 1.8 cm, p = 0.535. CONCLUSIONS: Component separation via both anterior and posterior approaches provide substantial myofascial advancement. In our model, we noted statistically greater anterior fascial medialization after PCS versus ACS as a whole, and especially in the upper and mid-abdomen. We advocate PCS as a reliable and possibly superior alternative for linea alba restoration for reconstructive repairs, especially for large defects in the upper and mid-abdomen.

Robotic-Assisted Transabdominal Preperitoneal Ventral Hernia Repair.

Ventral hernia repair is one of the most common operations performed by surgeons worldwide. The widespread adoption of laparoscopic surgery has significantly reduced complications related to traditional open approaches. The most common approach in laparoscopic ventral hernia repair is the intraperitoneal onlay mesh (IPOM) approach. This technique, though simple to perform, has limitations, including bridging mesh, intraperitoneal positioning of mesh, transfascial fixation, circumferential mesh fixation, and the use of more expensive composite mesh materials. These limitations are magnified when hernias occur in anatomically difficult sites such as the subxiphoid, suprapubic, and flank regions. Robotic-assisted hernia repair using a transabdominal preperitoneal (TAPP) approach has emerged as a viable alternative to traditional IPOM by potentially addressing these limitations. We review the operative considerations, intraoperative approach, and current body of literature related to robotic-assisted TAPP ventral hernia repair and conclude that it is feasible and may result in improved outcomes related to the restoration of abdominal wall anatomy and reduced operative costs. Further studies are needed to assess if robotic-assisted TAPP should become the standard approach for repair of ventral hernia defects.

Comparative analysis of perioperative outcomes of robotic versus open transversus abdominis release.

BACKGROUND: Transversus abdominis release (TAR) has evolved as an effective approach to complex abdominal wall reconstructions. Although the role of robotics in hernia surgery is rapidly expanding, the benefits of a robotic approach for abdominal wall reconstruction have not been established well. We aimed to compare the impact of the application of robotics to the TAR procedure on the perioperative outcomes when compared to the open TAR repairs. METHODS: Case-matched comparison of patients undergoing robotic TAR (R-TAR) at two specialized hernia centers to a matched historic cohort of open TAR (O-TAR) patients was performed. Outcome measures included patient demographics, operative details, postoperative complications, and length of hospitalization. RESULTS: 38 consecutive patients undergoing R-TAR were compared to 76 matched O-TAR. Patient demographics were similar between the groups, but ASA III status was more prevalent in the O-TAR group. The average operative time was significantly longer in the R-TAR group (299 ± 95 vs.. 211 ± 63 min, p < 0.001) and blood loss was significantly lower for the R-TAR group (49 ± 60 vs. 139 ± 149 mL, p < 0.001). Wound morbidity was minimal in the R-TAR, but the rate of surgical site events and surgical site infection was not different between groups. Systemic complications were significantly less frequent in the R-TAR group (0 vs. 17.1%, p = 0.026). The length of hospitalization was significantly reduced in the R-TAR group (1.3 ± 1.3 vs. 6.0 ± 3.4 days, p < 0.001). CONCLUSIONS: In our early experience, robotic TAR was associated with longer operative times. However, we found that the use of robotics was associated with decreased intraoperative blood loss, fewer systemic complications, shorter hospitalizations, and eliminated readmissions. While long-term outcomes and patient selection criteria for robotic TAR repair are under investigations, we advocate selective use of robotics for TAR reconstructions in patients undergoing AWR.

Is old age a contraindication to elective ventral hernia repair?

BACKGROUND: Ventral hernia repair (VHR) is a frequent problem in the expanding aging population. However, advanced age is often viewed as a contraindication to elective hernia surgery. We aimed to analyze outcomes of VHR in a large cohort of elderly patients. We hypothesized that elective VHR is safe and effective even in patients over 70 years old. METHODS: We conducted a retrospective review of consecutive patients over the age of 70 who underwent VHR at a at a tertiary care hospital. Main outcome measures included postoperative complications and recurrence rate. RESULTS: Between 2006 and 2015, 263 elderly patients who underwent elective VHR were included. Major comorbidities included diabetes, COPD, and smoking history. The majority of the patients underwent open repairs. Surgical site events occurred in 54 patients (21%). Postoperative complications included 17 venous thromboembolism occurrences, 2 myocardial infarctions, 41 patients who required postoperative critical care, and 1 mortality. Readmission within 90 days postoperatively occurred in 34 patients (13%). At a mean follow-up of 25.6 months, 17 patients in the open group and 6 patients in the laparoscopic group had a recurrence. CONCLUSION: We demonstrated that VHR can be performed reasonably safely and effectively even in this potentially risky cohort. The use of laparoscopy might be associated with further reduction in morbidity. Overall, age should not be a contraindication to elective VHR, even in patients over 70 years old.

Development of a novel murine model for treatment of infected mesh scenarios.

BACKGROUND: Indications regarding hernia repair after removal of previously infected prostheses remain unclear. Patients may receive staged primary repair or single-stage reconstructions, neither of which may be ideal. Although animal models have simulated contamination by direct inoculation of implants with bacteria, there remains a paucity of literature, which simulates a field following mesh infection and removal. We aimed to develop a murine model to mimic this complex scenario to allow for further testing of various implants. METHODS: Thirty-six female CL57BL/6J mice underwent implantation of a 0.7 × 0.7 cm polyester mesh in the dorsal subcutaneous position. Wounds were closed and inoculated with 100 µL containing 1 × 104 CFU of GFP-labeled MSSA. After 2 weeks, the infected mesh was removed and the cavity was copiously irrigated with saline. Mice were split into four groups: with three groups receiving new polyester, polypropylene, and porcine mesh and remaining as non-mesh controls. Mice were survived for another 2 weeks and underwent necropsy. Gross infection was evaluated at 2 and 4 weeks. Tissue homogenization and direct plating to recover GFP MSSA was completed at 4 weeks. RESULTS: At 2 weeks, all mice were noted to have gross mesh infection. One animal died due to overwhelming infection and wound breakdown. At 4 weeks, 5/6 (83 %) control mice who did not have a second mesh implantation had full clearance of their wounds. In contrast, 9/10 (90 %) mice with re-implantation of polypropylene were noted to have pus and recovery of GFP MSSA on plating. This was also observed in 100 % of mice with polyester and porcine mesh. CONCLUSION: Our novel murine model demonstrates that mesh re-implantation after infected mesh removal results in infection of the newly placed prosthesis, regardless of the material characteristic or type. This model lays foundation for development and investigation of implants for treatment strategies following infected mesh removal.

Evaluation of antibiotic pressurized pulse lavage for contaminated retromuscular abdominal wall reconstruction.

BACKGROUND: Despite patient risk factors such as diabetes and obesity, contamination during surgery remains a significant cause of infections and subsequent wound morbidity. Pressurized pulse lavage (PPL) has been utilized as a method to reduce bacterial bioburden with promising results in many fields. Although existing methods of lavage have been utilized during abdominal operations, no studies have examined the use of PPL during complex hernia repair. METHODS: Patients undergoing abdominal wall reconstruction (AWR) in clean-contaminated or contaminated fields with antibiotic PPL, from January 2012 to May 2013, were prospectively evaluated. Primary outcome measures studied were conversion of retrorectus space culture from positive to negative after PPL and 30-day surgical site infection (SSI) rate. RESULTS: A total of 56 patients underwent AWR, with 44 patients (78.6 %) having clean-contaminated fields and 12 patients (21.4 %) having contaminated ones. Twenty-two patients (39.3 %) had positive pre-PPL cultures, 18 of which (81.8 %) converted to negative cultures after PPL. Eleven patients (19.6 %) developed SSIs. Those with persistently positive cultures after PPL had the highest rate of SSI, where two out of four patients (50.0 %) developed an SSI. Contrastingly, only 5 of 18 patients (27.8 %) who converted from a positive to negative culture after PPL developed an SSI. CONCLUSION: Our findings demonstrate that antibiotic PPL is an effective method to reduce bacterial bioburden during AWR in clean-contaminated and contaminated fields. While complete conversion and eradication of SSI were not achieved, we believe that PPL may be a useful adjunct to standard operative asepsis in preventing prosthetic contamination during contaminated AWR.

Hiatal Hernia Repair: Current Evidence for Use of Absorbable Mesh to Reinforce Hiatal Closure.

INTRODUCTION: There continues to be debate regarding the best surgical technique for the treatment of paraesophageal hernias. While laparoscopic and robotic approaches are widely employed around the world, the benefits of mesh use to reinforce hiatal closure are still not well established. The goal of this manuscript is to describe the currently available results with biologic and bioabsorbable meshes for treatment of paraesophageal hernias, particularly with reference to the rate of recurrence. MATERIALS AND METHODS: A systematic review of the literature was conducted to identify studies describing treatment of hiatal hernias with biologic or bioabsorbable mesh. The available studies were categorized as comparative (when authors compared results with a different patient cohort undergoing suture repair of the hiatus without mesh reinforcement) and non-comparative, and organized by levels of evidence. RESULTS: We identified two randomized control trials, a long-term follow-up to one of the trials, a prospective case control study, one retrospective case control study, two meta-analyses of the above-mentioned studies, as well as 11 non-comparative studies, which included two prospective, 10 retrospective, and two case series. Most studies involved the use of different biologic meshes, while bioabsorbable mesh use was only described in four of the retrospective studies mentioned. The results are variable, however, most authors found a benefit from hiatal closure reinforcement with mesh. CONCLUSIONS: The available literature lacks definitive evidence to support the use of biologic or bioabsorbable materials to reinforce hiatal closure in the cure of paraesophageal hernias. Further studies are needed to assess newer materials and longer-term effects of existing products.

Outcomes of Posterior Component Separation With Transversus Abdominis Muscle Release and Synthetic Mesh Sublay Reinforcement.

OBJECTIVE: To evaluate the safety and efficacy of transversus abdominis muscle release (TAR) with retrorectus synthetic mesh reinforcement in a large series of complex hernia patients. BACKGROUND: Posterior component separation via TAR during abdominal wall reconstruction (AWR) continues to gain popularity. Although our early experience with TAR has been promising, long-term outcomes have not been reported. METHODS: From December 2006 to December 2014, consecutive patients undergoing open AWR utilizing TAR were identified in our prospectively maintained database and reviewed retrospectively. Main outcome measures included demographics, perioperative details, wound complications, and recurrences. RESULTS: During the study period, 428 consecutive TAR procedures were analyzed. Mean age was 58, with mean body mass index 34.4 kg/m (range 20-65). Major comorbidities included diabetes (21%), chronic obstructive pulmonary disease (12%), and immunosuppression (3%). Mean hernia defect area was 606 cm (range 180-1280) and average mesh size was 1220 cm (range 600-4500). The majority of cases (66%) were clean, 26% were clean-contaminated, and 8% were contaminated. Eighty (18.7%) surgical-site events occurred, of which 39 (9.1%) were surgical-site infections. Three patients required mesh debridement; however, no instances of mesh explantation occurred. Of the 347 (81%) patients with at least 1-year follow-up (mean 31.5 mo), there were 13 (3.7%) recurrences. CONCLUSIONS: Complex AWR represents a formidable surgical challenge. In this large series, we demonstrated that posterior component separation via TAR with wide synthetic mesh sublay provides a very durable repair with low morbidity, even in comorbid patients with large defects. We strongly advocate TAR as a robust addition to the armamentarium of reconstructive surgeons.

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.

Cell-coating affects tissue integration of synthetic and biologic meshes: comparative analysis of the onlay and underlay mesh positioning in rats.

BACKGROUND: While mesh reinforcement is recognized as the optimal strategy for many hernia repairs, there remains debate on the optimal position for deployment and characteristics that lead to improved biocompatibility. Coatings are an avenue by which integration may be improved. Our aim was to evaluate tissue integration between uncoated, fibroblast- and mesenchymal stem cell-coated meshes placed as subcutaneous onlay (ON) or intraperitoneal underlay (UN). METHODS: Three commonly used biologic and synthetic hernia meshes were tested including Parietex, TIGR and Strattice. Each mesh was coated with rat kidney fibroblasts (NRKs) or rat mesenchymal stem cells (MSCs) along with an uncoated group. In the ON group, mesh was fixated on top of the external oblique fascia. In the UN group, mesh was placed against the intact peritoneum. Animals were survived for 30 days and killed for biomechanical and histologic analysis. A "T"-peel test was performed on a mesh-tissue explant from each sample to analyze the strength of integration at the mesh-tissue interface. Tissue integration was evaluated histologically using an established scoring system. RESULTS: All uncoated meshes demonstrated significantly higher tissue ingrowth in the UN compared to ON position. Cell-coating of synthetic meshes decreased tissue ingrowth as UN, but increased it as ON, with a net effect of minimizing biomechanical difference between the two positions. In the biologic group however, NRK-coating decreased tissue ingrowth regardless of position, while MSC-coating increased it in both ON and UN positions. CONCLUSIONS: Both cell-coating and positioning affect mesh-tissue integration. Integration is superior in the underlay position compared to onlay when uncoated. Cell-coating of selected synthetic meshes can improve integration, particularly in the onlay position. Furthermore, MSCs appear to be a viable choice for biologic mesh coating, especially when implanted as an onlay. Overall, cell-coating of surgical meshes appears to a have a potential to improve mesh-tissue integration.

Evaluation of the Antimicrobial Efficacy of a Novel Rifampin/Minocycline-Coated, Noncrosslinked Porcine Acellular Dermal Matrix Compared With Uncoated Scaffolds for Soft Tissue Repair.

Background Despite meticulous aseptic technique and systemic antibiotics, bacterial colonization of mesh remains a critical issue in hernia repair. A novel minocycline/rifampin tyrosine-coated, noncrosslinked porcine acellular dermal matrix (XenMatrix AB) was developed to protect the device from microbial colonization for up to 7 days. The objective of this study was to evaluate the in vitro and in vivo antimicrobial efficacy of this device against clinically isolated methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli. Methods XenMatrix AB was compared with 5 existing uncoated soft tissue repair devices using in vitro methods of zone of inhibition (ZOI) and scanning electron microscopy (SEM) at 24 hours following inoculation with MRSA or E coli These devices were also evaluated at 7 days following dorsal implantation and inoculation with MRSA or E coli (60 male New Zealand white rabbits, n = 10 per group) for viable colony-forming units (CFU), abscess formation and histopathologic response, respectively. Results In vitro studies demonstrated a median ZOI of 36 mm for MRSA and 16 mm for E coli for XenMatrix AB, while all uncoated devices showed no inhibition of bacterial growth (0 mm). SEM also demonstrated no visual evidence of MRSA or E coli colonization on the surface of XenMatrix AB compared with colonization of all other uncoated devices. In vivo XenMatrix AB demonstrated complete inhibition of bacterial colonization, no abscess formation, and a reduced inflammatory response compared with uncoated devices. Conclusion We demonstrated that XenMatrix AB possesses potent in vitro and in vivo antimicrobial efficacy against clinically isolated MRSA and E coli compared with uncoated devices.

Antibiotic Coating of Hernia Meshes: The Next Step Toward Preventing Mesh Infection.

Mesh bacterial colonization/infection remains a critical issue in complex ventral hernia repair. Despite the recent emergence of biologic meshes, current strategies to prevent and treat mesh infection are largely ineffective, often leading to device failure and subsequent explantation along with the associated costs and effect on patient welfare. Unacceptably high rates of morbidity and hernia recurrence following mesh infection highlight the need for innovation in the area of hernia repair for the complex patient. One recent strategy to address such shortcomings is local antibiosis in the form of polymer coatings applied to the mesh itself. Current literature regarding the use of antibiotic-coated hernia mesh is limited but does illustrate the ability of these devices to inhibit bacterial growth and prevent mesh infection in both in vitro and in vivo studies. Although there is a paucity of literature regarding long-term clinical efficacy, this provides opportunity for further inquiry into a promising new development to combat mesh infective complications.

Effects of mesenchymal stem cell and fibroblast coating on immunogenic potential of prosthetic meshes in vitro.

BACKGROUND: The aim of this study was to reveal the effect of fibroblast or mesenchymal stem cell (MSC) coating on the mesh-induced production of IL-1ß, IL-6, and VEGF by macrophages. METHODS: Four commonly used surgical meshes were tested in this study, including Parietex, SoftMesh, TIGR, and Strattice. One-square-centimeter pieces of each mesh were placed on top of a monolayer of human fibroblasts or rat MSCs. The coating status was monitored with a light microscope. The human promonocytic cell line U937 was induced to differentiate into macrophages (MΦ). Three weeks later, meshes were transferred to new 24-well plates and cocultured with the MΦs for 72 h. Culture medium was collected and analyzed for IL-1ß, IL-6, and VEGF production using standard ELISA essays. Parallel mesh samples were fixed with paraformaldehyde or glutaraldehyde for histology or transmission electronic microscopy (TEM) analyses, respectively. RESULTS: Uncoated meshes induced increased production of all three cytokines compared with macrophages cultured alone. HF coating further increased the production of both IL-6 and VEGF but reduced IL-1ß production. Except for the SoftMesh group, MSC coating significantly blunted release of all cytokines to levels even lower than with MΦs cultured alone. MΦs tended to deteriorate in the presence of MSCs. Both histology and TEM revealed intimate interactions between cell-coated meshes and MΦs. CONCLUSIONS: Cytokine response to fibroblast coating varied, while MSC coating blunted the immunogenic effect of both synthetic and biologic meshes in vitro. Cell coating appears to affect mesh biocompatibility and may become a key process in mesh evolution.

Structured Resident Training in Robotic Surgery: Recommendations of the Robotic Surgery Education Working Group.

OBJECTIVE: A universal resident robotic surgery training pathway that maximizes proficiency and safety has not been defined by a consensus of surgical educators or by surgical societies. The objective of the Robotic Surgery Education Working Group was to develop a universal curriculum pathway and leverage digital tools to support resident education. DESIGN: The two lead authors (JP and YN) contacted potential members of the Working Group. Members were selected based on their authorship of peer-review publications, their experience as minimally invasive and robotic surgeons, their reputations, and their ability to commit the time involved to work collaboratively and efficiently to reach consensus regarding best practices in robotic surgery education. The Group's approach was to reach 100% consensus to provide a transferable curriculum that could be applied to the vast majority of resident programs. SETTING: Virtual and in-person meetings in the United States. PARTICIPANTS: Eight surgeons (2 females and 6 males) from five academic medical institutions (700-1541 beds) and three community teaching hospitals (231-607 beds) in geographically diverse locations comprised the Working Group. They represented highly specialized general surgeons and educators in their mid-to-late careers. All members were experienced minimally invasive surgeons and had national reputations as robotic surgery educators. RESULTS: The surgeons initially developed and agreed upon questions for each member to consider and respond to individually via email. Responses were collated and consolidated to present on an anonymized basis to the Group during an in-person day-long meeting. The surgeons self-facilitated and honed the agreed upon responses of the Group into a 5-level Robotic Surgery Curriculum Pathway, which each member agreed was relevant and expressed their convictions and experience. CONCLUSIONS: The current needs for a universal robotic surgery training curriculum are validated objective and subjective measures of proficiency, access to simulation, and a digital platform that follows a resident from their first day of residency through training and their entire career. Refinement of current digital solutions and continued innovation guided by surgical educators is essential to build and maintain a scalable, multi-institutional supported curriculum.

Effects of weight reduction surgery on the abdominal wall fascial wound healing process.

BACKGROUND: Bariatric surgery patients enter into a catabolic state postoperatively, which can lead to an aberrant wound healing process. To improve the future treatment of morbidly obese patients, the aim of our study was to understand the link between bariatric surgery and alterations in the wound healing processes. METHODS: A total of 18 morbidly obese Zucker rats were separated into three groups and underwent one of three surgical procedures: Roux-en-Y gastric bypass (RYGB; n = 6); sleeve gastrectomy (GS; n = 6); or midline laparotomy only (n = 6). The rats were weighed on postoperative day 0, 3, 7, and 14. On day 14, the abdominal wall was harvested and underwent histologic and biomechanical evaluation. RESULTS: A significant difference was found in the weight gain between the laparotomy control group (LC) and bariatric surgical groups at 7 and 14 d. By postoperative day 7, the GS and RYGB rats weighed significantly less than the LC group, losing, on average, 7% and 6% of their initial body weight, respectively, and the LC gained 4% of their weight (P < 0.05). By postoperative day 14, the LC had gained 20% of their original weight, and the two bariatric groups both weighed significantly less (P < 0.05). The breaking strength in the RYGB group (0.42 ± 0.18 N/mm) was significantly lower statistically than LC (0.69 ± 0/19 N/mm). The LC and GS groups (0.62 ± 0.27 N/mm) did not show a significant difference. The results of the histologic analysis showed that the collagen deposition in the wound was significantly lower statistically in the RYGB group compared with the LC group. No histologic difference was noted between the RYGB and GS groups. CONCLUSIONS: Malabsorptive bariatric surgery negatively affects wound healing both histologically and biomechanically compared with nonbariatric models. Although obesity remains a significant factor in the wound healing process, understanding the link between bariatric surgery and alterations in wound healing is imperative before advocating simultaneous repair of ventral hernias during concomitant bariatric surgery.

Laparoscopic mechanical fixation devices: does firing angle matter?

BACKGROUND: A variety of permanent and absorbable tacks are available for mesh fixation during laparoscopic hernia repairs. Although manufacturers recommend deploying tacks perpendicular to the tissue, achieving this can sometimes be challenging. This study aimed to analyze comparatively the effects of angled deployment among commonly used tacks. METHODS: A piece of composite mesh was fixed to the peritoneal surface of a pig with a single tack fired at either a perpendicular (90°) or acute (30°) angle. A lap-shear test was performed to determine fixation strength. Two permanent tacks (a titanium spiral tack: Protack [PT]; and a hollow screw fastener: PermaFix [PF]) and three absorbable tackers (a solid screw: Absorbatack [AT]; a hollow screw fastener: SorbaFix [SF]; and a strap: SecurStrap [SS]) were challenged. A total of 16 samples were performed for each device at each angle. A nonabsorbable transfascial suture was used as a control condition. RESULTS: Transabdominal sutures had the maximum acute tensile strength (ATS) (29.9 ± 5.5 N). Protack at both 90° and 30° performed significantly better than absorbable tacks (p < 0.01). No significant difference was found among absorbable tacks at 90°. When the same construct was compared at different angles, SS and SF performance was not affected (p = 0.07 and 0.2, respectively). In contrast, PT and AT had significantly reduced fixation strength (p = 0.003 and 0.004, respectively). However, PT fired at an acute angle had fixation equal to that of absorbable tacks fired perpendicularly. CONCLUSION: Transabdominal sutures performed better than tacks in the acute setting. No absorbable fixation device demonstrated superior efficacy within its class. Spiral titanium tacks provided better fixation than absorbable tacks at both perpendicular and acute angles. Moreover, titanium spiral tacks deployed at 30° performed equal to or better than absorbable tacks fired perpendicularly to the tissue. It appears that spiral titanium tacks should be strongly considered for cases in which perpendicular tack deployment cannot be achieved.

Decreased expression of hepatic signaling phosphoproteins after laparoscopic and hand-assisted surgery in a porcine model.

OBJECTIVE: Minimally-invasive surgery (MIS) is associated with a decreased activation of both systemic and peritoneal immunity compared with the open technique. However, hepatic response to laparoscopic (LAP) and hand-assisted laparoscopic (HAL) surgery has not been defined well. We postulated that both LAP and HAL approaches are associated with a diminished activation of hepatic inflammatory signaling pathways compared with the traditional open surgery. MATERIALS AND METHODS: Eighteen pigs underwent a transabdominal nephrectomy via Open, HAL, or LAP approach. Liver samples were obtained 24 h postoperatively and spot frozen. Frozen tissue samples were then homogenized and the nuclear pellets were separated and stored. Nuclear extracts were analyzed for activation of three nuclear signaling phosphoproteins: nuclear factor-kappaB (NFκB)-p65, heat-shock protein 27 (HSP27), and p38 mitogen-activated protein kinases (p38MAPK) using a standard Bioplex technique. Statistical comparison was performed using ANOVA and Student's t-test. RESULTS: The average expression of HSP27 was significantly higher in the Open versus either the LAP or the HAL groups (P = 0.028 and P = 0.039). The average expression of NFκB-p65 was significantly higher in the Open versus either the LAP or the HAL groups (P = 0.032 and P = 0.049). The average expression of p38MAPK was significantly higher in the Open versus either the LAP or the HAL groups (P = 0.007 and P = 0.036). There was no significant difference in the expressions of HSP27 and NFκB-p65 between LAP and HAL groups (P = 0.38 and P = 0.20), however, detection of p38MAPK generated statistical difference between these two groups (P = 0.018). CONCLUSION: Hand-assisted laparoscopic surgery has been widely accepted as an effective alternative to traditional laparoscopic procedures. We demonstrated that both laparoscopic and hand-assisted approaches resulted in blunted hepatic stress manifested by diminished expression of hepatic HSP27, NFκB, and p38-MAPK. In addition, the hand-assisted approach was equal to the laparoscopic approach in two of the three phosphoproteins studied. It appears that the use of hand-assisted techniques did not abrogate immunologic benefits of pure laparoscopy. Overall, in addition to the clinical benefits of minimal access, both hand-assisted and pure laparoscopic techniques may also confer an immunologic advantage over laparotomy.

Comparative analysis of histopathologic effects of synthetic meshes based on material, weight, and pore size in mice.

BACKGROUND: While synthetic prosthetics have essentially become mandatory for hernia repair, mesh-induced chronic inflammation and scarring can lead to chronic pain and limited mobility. Mesh propensity to induce such adverse effects is likely related to the prosthetic's material, weight, and/or pore size. We aimed to compare histopathologic responses to various synthetic meshes after short- and long-term implantations in mice. MATERIAL AND METHODS: Samples of macroporous polyester (Parietex [PX]), heavyweight microporous polypropylene (Trelex[TX]), midweight microporous polypropylene (ProLite[PL]), lightweight macroporous polypropylene (Ultrapro[UP]), and expanded polytetrafluoroethylene (DualMesh[DM]) were implanted subcutaneously in mice. Four and 12 wk post-implantation, meshes were assessed for inflammation, foreign body reaction (FBR), and fibrosis. RESULTS: All meshes induced varying levels of inflammatory responses. PX induced the greatest inflammatory response and marked FBR. DM induced moderate FBR and a strong fibrotic response with mesh encapsulation at 12 wk. UP and PL had the lowest FBR, however, UP induced a significant chronic inflammatory response. Although inflammation decreased slightly for TX, marked FBR was present throughout the study. Of the three polypropylene meshes, fibrosis was greatest for TX and slightly reduced for PL and UP. For UP and PL, there was limited fibrosis within each mesh pore. CONCLUSION: Polyester mesh induced the greatest FBR and lasting chronic inflammatory response. Likewise, marked fibrosis and encapsulation was seen surrounding ePTFE. Heavier polypropylene meshes displayed greater early and persistent fibrosis; the reduced-weight polypropylene meshes were associated with the least amount of fibrosis. Mesh pore size was inversely proportional to bridging fibrosis. Moreover, reduced-weight polypropylene meshes demonstrated the smallest FBR throughout the study. Overall, we demonstrated that macroporous, reduced-weight polypropylene mesh exhibited the highest degree of biocompatibility at sites of mesh implantation.

Evaluation of fibrin sealant for biologic mesh fixation at the hiatus in a porcine model.

BACKGROUND: The ideal method to secure biologic mesh during laparoscopic hiatal hernia repair remains uncertain. Suture or tack fixation can be technically difficult, and serious cardiovascular complications have been reported. Fibrin sealant (FS) offers a potential solution to this problem. We hypothesized that FS provides comparable mesh fixation to suture repair during laparoscopic mesh hiatoplasty. STUDY DESIGN: Using a porcine model, laparoscopic hiatal hernia repair was performed with suture reapproximation of the crura and reinforcement with an acellular porcine dermal matrix. Prior to repair, animals were randomized to mesh fixation with sutures (S) or FS. After 30-day survival, an esophagram was performed, the diaphragm harvested, and mesh position, fixation, and incorporation were evaluated histologically and biomechanically using a T-peel test. RESULTS: Twenty (10 S and 10 FS) laparoscopic hiatal hernia repairs were performed. Total operative time was significantly less in the FS group (74.7 versus 127.0 min, p < 0.01). There were no instances of mesh migration in any animal. Mean peel force did not differ significantly between the S and FS groups (0.21 vs. 0.18 N/mm, respectively; p = 0.49). There was no significant difference in cellular repopularization or inflammatory changes around the mesh. CONCLUSIONS: Fibrin sealant offers a reasonable alternative to suturing biologic mesh during laparoscopic hiatal hernia repair with equivalent mesh fixation. At 30 days it provides adhesive strength similar to suture fixation, while significantly reducing operative time.