A Novel Polypropylene Mesh (T-Line®) for Abdominal Wall Repair: Early Experience at Three Centers in the United States.

Mesh suture was initially developed and investigated to overcome suture pull-through in hernia repair. It has a large area compared to standard suture which distributes the load in tissue, reducing stress at the suture/tissue interface and preventing suture from cutting through tissue or the mesh. This report describes our early experience using the new T-line® mesh (Deep Blue Medical Advances, Durham, NC, USA) in patients with incisional and primary ventral hernia repairs. This is a descriptive, retrospective study in 18 patients who underwent abdominal wall repair with T-Line® mesh from November 2020 to November 2021 in three academic centers. T-Line® is a novel moderate-weight macroporous, polypropylene mesh with extensions that are 29 times the cross-sectional area of #0 polypropylene suture. They can be sewn into fascia to anchor the mesh with no need for suture tackers or other devices to fixate the mesh. The median age of the patients was 56.5 years (range 25-83) and the median BMI was 31.7 kg/m2 (range 23.6-51). Twelve patients (66.7%) had primary hernias, and 11 (61.1%) had a recurrent hernia. The median defect area was 117.5 cm2 (range 4-390) and the median mesh area was 449.5 cm2 (range 130-600). The mesh position was onlay in 16 cases (88.9%) and sublay in 2 cases (11.1%). The median operative time was 247 minutes (range 104-395). The median length of stay was six days (range 0-21) with no significant in-hospital complications. One patient had a surgical site infection (5.5%) and two patients developed seromas (11.1%). There were no early hernia recurrences with a median follow-up of 28 days (range 8-307). The T-Line® mesh was shown to be safe and effective for patients with ventral hernia in the short term.

Neonatal Hepatic Myeloid Progenitors Expand and Propagate Liver Injury in Mice.

BACKGROUND: Biliary atresia (BA) is a progressive pediatric inflammatory disease of the liver that leads to cirrhosis and necessitates liver transplantation. The rapid progression from liver injury to liver failure in children with BA suggests that factors specific to the perinatal hepatic environment are important for disease propagation. Hematopoietic stem and progenitor cells (HSPCs) reside in the fetal liver and are known to serve as central hubs of inflammation. We hypothesized that HSPCs are critical for the propagation of perinatal liver injury (PLI). METHODS: Newborn BALB/c mice were injected with rhesus rotavirus (RRV) to induce PLI or with PBS as control. Livers were compared using histology and flow cytometry. To determine the effects of HSPCs on PLI, RRV-infected neonatal mice were administered anti-CD47 and anti-CD117 to deplete HSPCs. RESULTS: PLI significantly increased the number of common myeloid progenitors and the number of CD34+ hematopoietic progenitors. Elimination of HSPCs through antibody-mediated myeloablation rescued animals from PLI and significantly increased survival (RRV+isotype control 36.4% vs. RRV+myeloablation 77.8%, Chi-test = 0.003). CONCLUSIONS: HSPCs expand as a result of RRV infection and propagate PLI. Targeting of HSPCs may be useful in preventing and treating neonatal inflammatory diseases of the liver such as BA.

Hand-Assisted Versus Pure Minimally-Invasive Distal Pancreatectomy: Is There a Downside to Lending a Hand?

BACKGROUND: Hand-assisted laparoscopic distal pancreatectomy (HALDP) is suggested to offer similar outcomes to pure laparoscopic distal pancreatectomy (LDP). However, given the longer midline incision, it is unclear whether HALDP increases the risk of postoperative hernia. Our aim was to determine the risk of postoperative incisional hernia development after HALDP. METHODS: We retrospectively collected data from patients undergoing HALDP or LDP at a single center (2012-2020). Primary endpoints were postoperative incisional hernia and operative time. All patients had at minimum six months of follow-up. Outcomes were compared using unadjusted and multivariable regression analyses. RESULTS: Ninety-five patients who underwent laparoscopic distal pancreatectomy were retrospectively identified. Forty-one patients (43%) underwent HALDP. Patients with HALDP were older (median, 67 vs. 61 years, p = 0.02). Sex, race, Body Mass Index (median, 27 vs. 26), receipt of neoadjuvant chemotherapy, gland texture, wound infection rates, postoperative pancreatic fistula, overall complications, and hospital length-of-stay were similar between HALDP and LDP (all p > 0.05). In unadjusted analysis, operative times were shorter for HALDP (164 vs. 276 min, p < 0.001), but after adjustment, did not differ significantly (MR 0.73; 0.49-1.07, p = 0.1). Unadjusted incidence of hernia was higher in HALDP versus LDP (60% vs. 24%, p = 0.004). After adjustment, HALDP was associated with an increased odds of developing hernia (OR 7.52; 95% CI 1.54-36.8, p = 0.014). After propensity score matching, odds of hernia development remained higher for HALDP (OR 4.62; 95% CI 1.28-16.65, p = 0.031) p = 0.03). CONCLUSIONS: Compared with LDP, HALDP was associated with increased likelihood of postoperative hernia with insufficient evidence that HALDP shortens operative times. Our results suggest that HALDP may not be equivalent to LDP.

Advances in the Treatment of Neonatal Biliary Disease.

This article discusses current standard of care in neonatal biliary disease, particularly management of biliary atresia and choledochal cysts. It highlights surgical considerations, guidelines for adjuvant therapies, and promising therapeutic options that are under investigation.

Minimally Invasive Distal Pancreatectomy Techniques: A Contemporary Analysis Exploring Trends, Similarities, and Differences to Open Surgery.

Limited contemporary data has compared similarities and differences between total laparoscopic (LDP), hand-assisted (HALDP), and open distal pancreatectomy (ODP). This study aimed to examine similarities and differences in outcomes between these three approaches in a contemporary cohort. Methods: Patients undergoing elective LDP, HALDP, and ODP in the NSQIP dataset (2014−2019) were included. Descriptive statistics and multivariate regression analyses were employed to compare postoperative outcomes. Results: Among 5636 patients, 33.9% underwent LDP, 13.1% HALDP, and 52.9% ODP. Compared with the LDP approach, surgical site infections were more frequent in HALDP and ODP approaches (1.2% vs. 2.6% vs. 2.8%, respectively, p < 0.01). After adjustment, the LDP approach was associated with a significantly lower likelihood of surgical site infection (OR 0.25, p = 0.03) when compared to ODP. There was no difference in the likelihood of surgical site infection when HALDP was compared to ODP (OR 0.59, p = 0.40). Unadjusted operative times were similar between approaches (LDP = 192 min, HALDP = 193 min, ODP = 191 min, p = 0.59). After adjustment, the LDP approach had a longer operative time (+10.3 min, p = 0.04) compared to ODP. There was no difference in the adjusted operative time between HALDP and ODP approaches (+5.4 min, p = 0.80). Conclusions: Compared to ODP, LDP was associated with improved surgical site infection rates and slightly longer operative times. There was no difference in surgical site infection rates between ODP and HALDP. Surgeon comfort and experience should decide the operative approach, but it is important to discuss the differences between these approaches with patients.

Hepatic Ly6CLo Non-Classical Monocytes Have Increased Nr4a1 (Nur77) in Murine Biliary Atresia.

Biliary atresia (BA) is a rapidly progressive perinatal inflammatory disease, resulting in liver failure. Hepatic Ly6CLo non-classical monocytes promote the resolution of perinatal liver inflammation during rhesus rotavirus-mediated (RRV) BA in mice. In this study, we aim to investigate the effects of inflammation on the transcription factor Nr4a1, a known regulator of non-classical monocytes. Nr4a1-GFP reporter mice were injected with PBS for control or RRV within 24 h of delivery to induce perinatal liver inflammation. GFP expression on myeloid immune populations in the liver and bone marrow (BM) was quantified 3 and 14 days after injection using flow cytometry. Statistical significance was determined using a student's t-test and ANOVA, with a p-value < 0.05 for significance. Our results demonstrate that non-classical monocytes in the neonatal liver exhibit the highest mean fluorescence intensity (MFI) of Nr4a1 (Ly6CLo MFI 6344 vs. neutrophils 3611 p < 0.001; macrophages 2782; p < 0.001; and Ly6CHi classical monocytes 4485; p < 0.0002). During inflammation, hepatic Ly6CLo non-classical monocytes showed a significant increase in Nr4a1 expression intensity from 6344 to 7600 (p = 0.012), while Nr4a1 expression remained unchanged on the other myeloid populations. These findings highlight the potential of using Nr4a1 as a regulator of neonatal hepatic Ly6CLo non-classical monocytes to mitigate perinatal liver inflammation.

Bursting the Hidden Curriculum Bubble: A Surgical Near-Peer Mentorship Pilot Program for URM Medical Students.

The hidden curriculum of unspoken professional expectations negatively impacts medical student interest in surgery. Medical student mentorship and early surgical exposure have been shown to demystify the hidden curriculum. Although residents and faculty play a vital role, near-peer mentorship may aid in uncovering the hidden curriculum and promoting medical student interest in surgery, especially for those learners who are underrepresented in medicine. We developed and implemented a formalized near-peer mentorship program composed of quarterly small group Surgical Peer Teacher led lessons and one-on-one Surgical Support Team mentorship meetings covering surgical curriculum topics for medical students at an academic medical school. This structured near-peer mentorship model provides a mechanism to demystify surgical culture, increase early access to surgical mentorship, and develop mentorship skills amongst students. This program aims to uncover the surgical hidden curriculum to improve surgical career support and interest among medical students with less exposure and access to physician role models. This longitudinal mentorship model is student-run and can be easily adapted to enhance existing support models at medical schools. Future studies will evaluate utilization, impact on surgical specialty interest, and efficacy in demystifying the surgical hidden curriculum.

Determining Hospital Volume Threshold for Safety of Minimally Invasive Pancreaticoduodenectomy: A Contemporary Cutpoint Analysis.

BACKGROUND: Guidelines recommend limiting minimally invasive pancreaticoduodenectomy (MIPD) to high-volume centers. However, the definition of high-volume care remains unclear. We aimed to objectively define a minimum number of MIPD performed annually per hospital associated with improved outcomes in a contemporary patient cohort. PATIENTS AND METHODS: Resectable pancreatic adenocarcinoma patients undergoing MIPD were included from the National Cancer Database (2010-2017). Multivariable modeling with restricted cubic splines was employed to identify an MIPD annual hospital volume threshold associated with lower 90-day mortality. Outcomes were compared between patients treated at low-volume (≤ model-identified cutoff) and high-volume (> cutoff) centers. RESULTS: Among 3079 patients, 141 (5%) died within 90 days. Median hospital volume was 6 (range 1-73) cases/year. After adjustment, increasing hospital volume was associated with decreasing 90-day mortality for up to 19 (95% CI 16-25) cases/year, indicating a threshold of 20 cases/year. Most cases (82%) were done at low-volume (< 20 cases/year) centers. With adjustment, MIPD at low-volume centers was associated with increased 90-day mortality (OR 2.7; p = 0.002). Length of stay, positive surgical margins, 30-day readmission, and overall survival were similar. On analysis of the most recent two years (n = 1031), patients at low-volume centers (78.2%) were younger and had less advanced tumors but had longer length of stay (8 versus 7 days; p < 0.001) and increased 90-day mortality (7% versus 2%; p = 0.009). CONCLUSIONS: The cutpoint analysis identified a threshold of at least 20 MIPD cases/year associated with lower postoperative mortality. This threshold should inform national guidelines and institution-level protocols aimed at facilitating the safe implementation of this complex procedure.

Unifying the Hepatopancreatobiliary Surgery Fellowship Curriculum via Delphi Consensus.

BACKGROUND: Hepatopancreatobiliary (HPB) Fellowship training in the Americas consists of 3 distinctive routes with variable curricula: Surgical Oncology Fellowship via the Society of Surgical Oncology (SSO), Abdominal Transplant Surgery Fellowship via the American Society of Transplant Surgeons (ASTS), and HPB Fellowship via the Americas Hepato-Pancreato-Biliary Association (AHPBA). Our objective was to establish a pan-American consensus among HPB surgeons, surgical oncologists, abdominal transplant surgeons, and general surgery residency program directors (GSPDs) on a core knowledge curriculum for HPB fellowship, and to identify topics appropriate for general surgery residency and subspecialty beyond HPB fellowship. STUDY DESIGN: A 3-round modified Delphi process was used. Baseline statements were developed by the Education and Training Committee of the AHPBA, in collaboration with representatives of the SSO, ASTS, and GSPDs. The expert panel, consisting of members of the 3 societies together with GSPDs, rated the statements on a 5-point Likert scale and suggested editing or adding new statements. A statement was included in the final curriculum when Cronbach's alpha value was ≥ 0.8 and ≥ 80% of the panel agreed on inclusion. RESULTS: The response rate was 100% for the first round, and 98% for the second and third rounds. Eighty-nine of 138 proposed statements were included in the final HPB fellowship curriculum. Curricula for general surgery residency and subspecialty beyond HPB fellowship included 50 and 29 statements, respectively. CONCLUSIONS: A multinational consensus on core knowledge for an HPB fellowship curriculum was achieved via the modified Delphi method. This core curriculum may be used to standardize HPB fellowship training across different pathways in the Americas.

The Role of Myeloid Populations during Perinatal Liver Injury and Repair.

Perinatal liver inflammation can have life-threatening consequences, particularly in infants and young children. An example of a hepatic inflammatory disease during infancy is biliary atresia (BA), an obliterative cholangiopathy that rapidly progresses to hepatic fibrosis and liver failure. The aggressive nature of BA in neonates compared to the pathogenesis of inflammatory liver diseases in adults, suggests that the mechanisms responsible for restoring tissue homeostasis following inflammation are impaired in affected infants. This article reviews our recent findings demonstrating that the relative abundance of Ly6cLo non-classical monocytes promotes resolution of perinatal liver injury in a murine model of perinatal hepatic inflammation. Our research also identifies a potential co-regulatory role between neutrophils and non-classical monocytes. Further work is needed to understand how neutrophils regulate other myeloid populations during perinatal liver inflammation. Elucidating the mechanisms that govern perinatal liver injury and repair may lead to the development of immune-directed therapies that can be used to mitigate the devastating effects of diseases like BA.

The relative abundance of monocyte subsets determines susceptibility to perinatal hepatic inflammation.

The devastating consequences of perinatal liver inflammation contribute to a pressing need to develop therapeutics for the diseases that underly this condition. Biliary atresia (BA) is a perinatal inflammatory disease of the liver that results in obliterative cholangiopathy and rapidly progresses to liver failure, requiring transplantation. The ability to develop targeted therapies requires an understanding of the immune mechanisms that mitigate perinatal liver inflammation. This article reviews our recent findings demonstrating that in a murine model of perinatal hepatic inflammation, Ly6cLo non-classical monocytes express a pro-reparative transcriptomic profile and that the relative abundance of Ly6cLo monocytes promotes resolution of perinatal liver inflammation, rendering neonatal pups resistant to disease. We also examine the lineage relationship between monocyte subsets, reviewing data that suggests classical monocytes are a precursor for non-classical monocytes, and the alternative possibility that separate progenitors exist for each subset. Although a precursor-product relationship between classical and non-classical monocytes might exist in certain environments, we argue that they may also arise from separate progenitors, which is evident by sustained Ly6cLo non-classical monocyte expansion when Ly6cHi monocytes are absent. An improved understanding of monocyte subsets and their developmental trajectories during perinatal hepatic inflammation will provide insight into how therapies directed at controlling monocyte function may help alleviate the devastating consequences of diseases like BA.