Quantitative Tension on the Abdominal Wall in Posterior Components Separation With Transversus Abdominis Release.

Importance: Posterior components separation (PCS) is a commonly used myofascial release technique in ventral hernia repairs. The contribution of each release with anterior and posterior fascial advancement has not yet been characterized in patients with ventral hernias. Objective: To quantitatively assess the changes in tension on the anterior and posterior fascial elements of the abdominal wall during PCS to inform surgeons regarding the technical contribution of each step with those changes, which may help to guide intraoperative decision-making. Design, Setting, and Participants: This case series enrolled patients from December 2, 2021, to August 2, 2022, and was conducted at the Cleveland Clinic Center for Abdominal Core Health. The participants included adult patients with European Hernia Society classification M1 to M5 ventral hernias undergoing abdominal wall reconstruction with PCS. Intervention: A proprietary, sterilizable tensiometer measured the force needed to bring the fascial edge of the abdominal wall to the midline after each step of a PCS (retrorectus dissection, division of the posterior lamella of the internal oblique aponeurosis, and transversus abdominis muscle release [TAR]). Main Outcome: The primary study outcome was the percentage change in tension on the anterior and posterior fascia associated with each step of PCS with TAR. Results: The study included 100 patients (median [IQR] age, 60 [54-68] years; 52 [52%] male). The median (IQR) hernia width was 13.0 (10.0-15.2) cm. After complete PCS, the mean (SD) percentage changes in tension on the anterior and posterior fascia were -53.27% (0.53%) and -98.47% (0.08%), respectively. Of the total change in anterior fascial tension, retrorectus dissection was associated with a mean (SD) percentage change of -82.56% (0.68%), incision of the posterior lamella of the internal oblique with a change of -17.67% (0.41%), and TAR with no change. Of the total change in posterior fascial tension, retrorectus dissection was associated with a mean (SD) percentage change of -3.04% (2.42%), incision of the posterior lamella of the internal oblique with a change of -58.78% (0.39%), and TAR with a change of -38.17% (0.39%). Conclusions and Relevance: In this case series, retrorectus dissection but not TAR was associated with reduced tension on the anterior fascia, suggesting that it should be performed if anterior fascial advancement is needed. Dividing the posterior lamella of the internal oblique aponeurosis and TAR was associated with reduced tension on the posterior fascia, suggesting that it should be performed for posterior fascial advancement.

Early wound morbidity and clinical outcomes associated with P4HB mesh compared to permanent synthetic mesh in umbilical and small to medium, routine ventral hernia repairs.

Background: Permanent synthetic meshes such as polypropylene (PP) have been utilized for hernia repair for decades, but concerns remain regarding potential long-term, mesh-related complications. A resorbable polymer such as poly-4-hydroxybutyrate (P4HB) represents an alternative with high initial strength, that gradually resorbs, leaving an abdominal wall that is at least as strong as it would be in its native state. We aimed to compare early wound morbidity and clinical outcomes associated with P4HB to traditional, permanent PP in umbilical and small to medium, routine ventral hernias using data from the Abdominal Core Health Quality Collaborative (ACHQC). Methods: Inclusion criteria for the umbilical cohort included: all Centers for Disease Control and Prevention (CDC) wound classes, all Ventral Hernia Working Group (VHWG) hernia grades, and hernia defects <3 cm. The small to medium, routine ventral hernia cohort was limited to CDC class I wounds, VHWG hernia grades I and II, and hernia defects <5 cm. The study group was comprised of P4HB meshes; the comparator group was an aggregate of PP meshes. Clinical outcomes were assessed at 30 days. Results: There was no significant difference in early wound morbidity, readmission, or reoperation between the P4HB and PP cohorts. A small number of patients experienced SSO, with ≤4% requiring procedural intervention. None of the patients (0% in all cases) experienced skin/soft tissue necrosis, infected seroma, infected hematoma, exposed/contaminated/infected mesh, enterocutaneous fistula, graft failure, or pain requiring intervention at 30-days. However, P4HB was associated with significantly greater operative time, length of stay, and use of myofascial release compared to PP (p < 0.05 in all cases). Conclusions: Short-term clinical outcomes associated with resorbable P4HB mesh are comparable to permanent synthetic PP mesh in umbilical and small to medium, routine ventral hernia repairs, despite significant differences in operative time and length of stay. Longer-term follow-up is needed to expand on the clinical relevance of these short-term findings.

A Micro-longitudinal Approach to Measuring Medication Adherence in Pediatric Inflammatory Bowel Diseases.

Measuring medication adherence in pediatric inflammatory bowel diseases (IBD) is challenging because of complexities in personalized treatment regimens and increased use of biologic mono- and combination therapy. Objective measurement of adherence via electronic monitoring is the gold standard; however, it is not useful for daily monitoring when multiple medication formulations (eg, pills, injections, infusions) as well as vitamins/supplements are prescribed. Although validated subjective measures are available, they are not designed for daily use and do not capture day-to-day variation in adherence. In the following article, a new approach to measuring adherence regardless of a patient's specific medication regimen is presented. Utilizing a micro-longitudinal design, 30 days of daily self-reported medication adherence data was collected from youth with IBD via text message. Results reflect mean adherence rates from studies utilizing pill counts and electronic monitoring, suggesting promise for the use of self-reported daily diaries to assess medication adherence in pediatric IBD.

An Evaluation of Parastomal Hernia Repair Using the Americas Hernia Society Quality Collaborative.

The purpose of this review was to evaluate outcomes relating to parastomal hernia repair. Data from the Americas Hernia Society Quality Collaborative were used to identify patients undergoing parastomal hernia repair from 2013 to 2016. Parastomal hernia repairs were compared with other repairs using Pearson's test and Wilcoxon test with a P value <0.05 considered significant. Parastomal hernia repairs were performed in 311 patients. Techniques of repair include open in 85 per cent and laparoscopic in 15 per cent. Mesh was used in 92 per cent with keyhole in 34 per cent, flat mesh in 33 per cent, and Sugarbaker in 25 per cent. Mesh types were permanent synthetic in 79 per cent, biologic in 13 per cent, absorbable synthetic in 6 per cent, and hybrid synthetic/biologic in 2 per cent. Most common location for mesh was sublay in 84 per cent followed by onlay in 14 per cent and inlay in 2 per cent with 59 per cent of patients undergoing a myofascial release. Ostomy disposition included ostomy left in situ (47%), moved to a new site (18%), taken down (22%), and rematured in same location in (13%). Outcomes related to parastomal hernia repair included 10 per cent surgical site infection, 24 per cent surgical site occurrence, and 12 per cent surgical site occurrences requiring procedural interventions with a 13 per cent readmission rate and 6 per cent reoperation rate. When comparing parastomal hernias with other ventral hernia repairs, parastomal hernias had a significantly higher surgical site infection, surgical site occurrence, surgical site occurrences requiring procedural intervention, readmission, reoperation rate, and length of stay, and were less commonly performed laparoscopically (P < 0.05). Most parastomal hernias are being repaired open with synthetic mesh in the sublay position. Less favorable outcomes of parastomal hernia repair when compared with other ventral hernia repairs are likely related to the complexity of parastomal hernia repair.

Multicenter, Prospective, Longitudinal Study of the Recurrence, Surgical Site Infection, and Quality of Life After Contaminated Ventral Hernia Repair Using Biosynthetic Absorbable Mesh: The COBRA Study.

OBJECTIVE: The aim of the study was to evaluate biosynthetic absorbable mesh in single-staged contaminated (Centers for Disease Control class II and III) ventral hernia (CVH) repair over 24 months. BACKGROUND: CVH has an increased risk of postoperative infection. CVH repair with synthetic or biologic meshes has reported chronic biomaterial infections and high hernia recurrence rates. METHODS: Patients with a contaminated or clean-contaminated operative field and a hernia defect at least 9 cm had a biosynthetic mesh (open, sublay, retrorectus, or intraperitoneal) repair with fascial closure (n = 104). Endpoints included overall Kaplan-Meier estimates for hernia recurrence and postoperative wound infection rates at 24 months, and the EQ-5D and Short Form 12 Health Survey (SF-12). Analyses were conducted on the intent-to-treat population, and health outcome measures evaluated using paired t tests. RESULTS: Patients had a mean age of 58 years, body mass index of 28 kg/m, 77% had contaminated wounds, and 84% completed 24-months follow-up. Concomitant procedures included fistula takedown (n = 24) or removal of infected previously placed mesh (n = 29). Hernia recurrence rate was 17% (n = 16). At the time of CVH repair, intraperitoneal placement of the biosynthetic mesh significantly increased the risk of recurrences (P ≤ 0.04). Surgical site infections (19/104) led to higher risk of recurrence (P < 0.01). Mean 24-month EQ-5D (index and visual analogue) and SF-12 physical component and mental scores improved from baseline (P < 0.05). CONCLUSIONS: In this prospective longitudinal study, biosynthetic absorbable mesh showed efficacy in terms of long-term recurrence and quality of life for CVH repair patients and offers an alternative to biologic and permanent synthetic meshes in these complex situations.

Permissible Intraabdominal Hypertension following Complex Abdominal Wall Reconstruction.

BACKGROUND: Repair of hernias with loss of domain can lead to elevated intraabdominal pressure. The authors aimed to characterize the effects of elective hernia repair on intraabdominal pressure, as well as its predictors and association with negative outcomes. METHODS: Patients undergoing elective hernia repair requiring myofascial release had intraabdominal and pulmonary plateau pressures measured preoperatively, postoperatively, and on the morning of the first postoperative day. Loss of domain was measured by preoperative computed tomography. Outcome measures included predictors of an increase in plateau pressure, respiratory complications, and acute kidney injury. RESULTS: Following 50 consecutive cases, diagnoses of intraabdominal hypertension (92 percent), abdominal compartment syndrome (16 percent), and abdominal perfusion pressure less than 60 mmHg (24 percent) were determined. Changes in intraabdominal pressure (preoperative, 12.7 ± 4.0 mmHg; postoperative, 18.2 ± 5.4 mmHg; postoperative day 1, 12.9 ± 5.2 mmHg) and abdominal perfusion pressure (preoperative, 74.7 ± 15.7; postoperative, 70.0 ± 14.4; postoperative day 1, 74.9 ± 11.6 mmHg) consistently resolved by postoperative day 1, and were not associated with respiratory complications or acute kidney injury. Patients who remained intubated postoperatively for an elevation in pulmonary plateau pressure (≥6 mmHg) all demonstrated an improvement in plateau pressure by postoperative day 1 (preoperative, 18.9 ± 4.5 mmHg; postoperative, 27.4 ± 4.0 mmHg; postoperative day 1, 20.1 ± 3.7 mmHg), and could be identified preoperatively as having a hernia volume of greater than 20 percent of the abdominal cavity (p < 0.001), but were still more likely to have postoperative respiratory events (p = 0.01). CONCLUSIONS: Elevated intraabdominal pressure following elective hernia repair requiring myofascial releases is common but transient. Change in plateau pressure by 6 mmHg or more following repair can be expected with a loss of domain greater than 20 percent and is a more useful surrogate than intraabdominal pressure measurements with regard to predicting postoperative pulmonary complications. The perception and management of elevated intraabdominal pressure should be considered distinct and "permissible" in this context.

Small intestinal intraepithelial TCRγδ+ T lymphocytes are present in the premature intestine but selectively reduced in surgical necrotizing enterocolitis.

BACKGROUND: Gastrointestinal barrier immaturity predisposes preterm infants to necrotizing enterocolitis (NEC). Intraepithelial lymphocytes (IEL) bearing the unconventional T cell receptor (TCR) γδ (γδ IEL) maintain intestinal integrity and prevent bacterial translocation in part through production of interleukin (IL) 17. OBJECTIVE: We sought to study the development of γδ IEL in the ileum of human infants and examine their role in NEC pathogenesis. We defined the ontogeny of γδ IEL proportions in murine and human intestine and subjected tcrδ-/- mice to experimental gut injury. In addition, we used polychromatic flow cytometry to calculate percentages of viable IEL (defined as CD3+ CD8+ CD103+ lymphocytes) and the fraction of γδ IEL in surgically resected tissue from infants with NEC and gestational age matched non-NEC surgical controls. RESULTS: In human preterm infants, the proportion of IEL was reduced by 66% in 11 NEC ileum resections compared to 30 non-NEC controls (p<0.001). While γδ IEL dominated over conventional αß IEL early in gestation in mice and in humans, γδ IEL were preferential decreased in the ileum of surgical NEC patients compared to non-NEC controls (50% reduction, p<0.05). Loss of IEL in human NEC was associated with downregulation of the Th17 transcription factor retinoic acid-related orphan nuclear hormone receptor C (RORC, p<0.001). TCRδ-deficient mice showed increased severity of experimental gut injury (p<0.05) with higher TNFα expression but downregulation of IL17A. CONCLUSION: Complimentary mouse and human data suggest a role of γδ IEL in IL17 production and intestinal barrier production early in life. Specific loss of the γδ IEL fraction may contribute to NEC pathogenesis. Nutritional or pharmacological interventions to support γδ IEL maintenance in the developing small intestine could serve as novel strategies for NEC prevention.

Deletion of cationic amino acid transporter 2 exacerbates dextran sulfate sodium colitis and leads to an IL-17-predominant T cell response.

L-Arginine (L-Arg) is a semiessential amino acid that has altered availability in human ulcerative colitis (UC), a form of inflammatory bowel disease, and is beneficial in murine colitis induced by dextran sulfate sodium (DSS), a model with similarity to UC. We assessed the role of cationic amino acid transporter 2 (CAT2), the inducible transporter of L-Arg, in DSS colitis. Expression of CAT2 was upregulated in tissues from colitic mice and localized predominantly to colonic macrophages. CAT2-deficient (CAT2-/-) mice exposed to DSS exhibited worsening of survival, body weight loss, colon weight, and histological injury. These effects were associated with increased serum L-Arg and decreased tissue L-Arg uptake and inducible nitric oxide synthase protein expression. Clinical benefits of L-Arg supplementation in wild-type mice were lost in CAT2-/- mice. There was increased infiltration of macrophages, dendritic cells, granulocytes, and T cells in colitic CAT2-/- compared with wild-type mice. Cytokine profiling revealed increases in proinflammatory granulocyte colony-stimulating factor, macrophage inflammatory protein-1α, IL-15, and regulated and normal T cell-expressed and -secreted and a shift from an IFN-γ- to an IL-17-predominant T cell response, as well as an increase in IL-13, in tissues from colitic CAT2-/- mice. However, there were no increases in other T helper cell type 2 cytokines, nor was there a global increase in macrophage-derived proinflammatory cytokines. The increase in IL-17 derived from both CD4 and γδ T cells and was associated with colonic IL-6 expression. Thus CAT2 plays an important role in controlling inflammation and IL-17 activation in an injury model of colitis, and impaired L-Arg availability may contribute to UC pathogenesis.

L-arginine supplementation improves responses to injury and inflammation in dextran sulfate sodium colitis.

Inflammatory bowel disease (IBD), consisting of Crohn's disease and ulcerative colitis (UC), results in substantial morbidity and is difficult to treat. New strategies for adjunct therapies are needed. One candidate is the semi-essential amino acid, L-arginine (L-Arg), a complementary medicine purported to be an enhancer of immunity and vitality in the lay media. Using dextran sulfate sodium (DSS) as a murine colonic injury and repair model with similarities to human UC, we assessed the effect of L-Arg, as DSS induced increases in colonic expression of the y(+) cationic amino acid transporter 2 (CAT2) and L-Arg uptake. L-Arg supplementation improved the clinical parameters of survival, body weight loss, and colon weight, and reduced colonic permeability and the number of myeloperoxidase-positive neutrophils in DSS colitis. Luminex-based multi-analyte profiling demonstrated that there was a marked reduction in proinflammatory cytokine and chemokine expression with L-Arg treatment. Genomic analysis by microarray demonstrated that DSS-treated mice supplemented with L-Arg clustered more closely with mice not exposed to DSS than to those receiving DSS alone, and revealed that multiple genes that were upregulated or downregulated with DSS alone exhibited normalization of expression with L-Arg supplementation. Additionally, L-Arg treatment of mice with DSS colitis resulted in increased ex vivo migration of colonic epithelial cells, suggestive of increased capacity for wound repair. Because CAT2 induction was sustained during L-Arg treatment and inducible nitric oxide (NO) synthase (iNOS) requires uptake of L-Arg for generation of NO, we tested the effect of L-Arg in iNOS(-/-) mice and found that its benefits in DSS colitis were eliminated. These preclinical studies indicate that L-Arg supplementation could be a potential therapy for IBD, and that one mechanism of action may be functional enhancement of iNOS activity.