Implant Porosity and the Foreign Body Response.

The biocompatibility of prosthetic mesh is dependent on a number of physicochemical properties that ultimately incite an optimal foreign body response. The magnitude and character of the foreign body response directly affect the clinical success of the hernia repair, with too little scar resulting in bulge or hernia recurrence and too much scar causing mesh wrinkling and pain. Moreover, it is important to consider the effect of a sustained foreign body response and scar remodeling on the combined strength of the mesh-tissue construct over time. Understanding key elements that determine the foreign body response, such as implant porosity, surface area, and filament size, is critical to the performance of surgery. New absorbable materials introduce the additional variable of durability and persistence of the foreign body response after the foreign body itself has dissolved. In this review, we discuss the experimental and clinical literature relating the quality of the foreign body response to the physical attributes of implants in an effort to demystify prosthetic mesh selection.

Current Risk Stratification Systems Are Not Generalizable across Surgical Technique in Midline Ventral Hernia Repair.

BACKGROUND: Current ventral hernia repair risk estimation tools focus on patient comorbidities with the goal of improving clinical outcomes through improved patient selection. However, their predictive value remains unproven. METHODS: Outcomes of patients who underwent midline ventral hernia repair with retrorectus placement of mid-weight soft polypropylene mesh between 2010 and 2015 were retrospectively reviewed and compared with predicted wound-related complication risk from 3 tools in the literature: Carolinas Equation for Determining Associated Risk, the Ventral Hernia Working Group (VHWG) grade, and a modified VHWG grade. RESULTS: A total of 101 patients underwent hernia repair. Mean age was 56 years and mean body mass index was 29 m/kg2 (range, 18-51 m/kg2). We found no significant relationship between the risk estimated by Carolinas Equation for Determining Associated Risk (B = 1.45, P = 0.61) and actual wound-related complications. VHWG grades >1 were not statistically different with regard to rate of wound complication compared with VHWG grade 1 (grade 2: B = 0.05, P = 0.95; grade 3: B = -0.21, P = 0.86; grade 4: B = 2.57, P = 0.10). Modified VHWG grades >1 were not statistically different with regard to rate of wound complication compared with modified VHWG grade 1 (grade 2: B = 0.20, P = 0.80; grade 3: B = 1.03, P = 0.41). CONCLUSIONS: Current risk stratification tools overemphasize patient factors, ignoring the importance of technique in minimizing complications and recurrence. We attribute our low complication rate to retrorectus placement of a narrow, macroporous polypropylene mesh with up to 45 suture fixation points for force distribution in contrast to current strategies that employ wide meshes with minimal fixation.

Reliable complex abdominal wall hernia repairs with a narrow, well-fixed retrorectus polypropylene mesh: A review of over 100 consecutive cases.

BACKGROUND: Our objective was to determine outcomes for complex ventral hernia repairs in a large cohort of patients utilizing an operative construct employing retrorectus placement of a narrow, macroporous polypropylene mesh with up to 45 suture fixation points for force distribution. No consensus exists on the optimal technique for repair of complex ventral hernias. Current trends emphasize large meshes with wide overlaps and minimal suture fixation, though reported complications and recurrence remain problematic. METHODS: A retrospective review was performed for all patients undergoing ventral hernia repair with retrorectus placement of midweight, uncoated, soft polypropylene mesh by a single surgeon (GAD) between the years of 2010 and 2015. Patient characteristics, operative history, operative data, and postoperative course were reviewed. RESULTS: A total of 101 patients with a mean age of 56 years and a mean body mass index of 29 m/kg2 (range 18-51 m/kg2) underwent hernia repair. Patients had a median of 3 prior abdominal operations (range 0-9), with 44 patients presenting with recurrent hernias. A total of 42 patients were Ventral Hernia Working Group grade 1, 40 grade 2, 17 grade 3, and 2 grade 4. There were no recurrences at a mean follow-up of almost 400 days for the 93 patients with long-term follow-up. The surgical site occurrence rate was 7.9% (3 surgical site infections, 2 seromas, 2 hematomas, and 4 instances of delayed wound healing in 8 patients). One patient required reoperation for hematoma drainage; 5 patients required readmission within 30 days. CONCLUSION: An operative construct employing a retrorectus placement of a narrow, macroporous polypropylene mesh with up to 45 suture fixation points for force distribution can achieve significantly better outcomes across a spectrum of Ventral Hernia Working Group grade, risk-stratified patients compared to rates reported in the literature for current strategies that employ wide meshes with minimal fixation.

Combinatorial Histone Readout by the Dual Plant Homeodomain (PHD) Fingers of Rco1 Mediates Rpd3S Chromatin Recruitment and the Maintenance of Transcriptional Fidelity.

The plant homeodomain (PHD) finger is found in many chromatin-associated proteins and functions to recruit effector proteins to chromatin through its ability to bind both methylated and unmethylated histone residues. Here, we show that the dual PHD fingers of Rco1, a member of the Rpd3S histone deacetylase complex recruited to transcribing genes, operate in a combinatorial manner in targeting the Rpd3S complex to histone H3 in chromatin. Although mutations in either the first or second PHD finger allow for Rpd3S complex formation, the assembled complexes from these mutants cannot recognize nucleosomes or function to maintain chromatin structure and prevent cryptic transcriptional initiation from within transcribed regions. Taken together, our findings establish a critical role of combinatorial readout in maintaining chromatin organization and in enforcing the transcriptional fidelity of genes.