October 2023

This is a prospective observational study of 526 infants who underwent laparoscopic pyloromyotomy. During surgery, their inguinal canals were examined for the presence of a patent processus vaginalis (PPV); they were then followed annually to determine the incidence and timing of any subsequent inguinal hernia development and need for repair. This study showed that while there was a high incidence of PPV during surgery, the need for inguinal hernia repair is low. 

Summary:

Inguinal hernias are common in both men and women, with indirect inguinal hernias being the most frequently encountered type. These hernias are believed to arise due to a persistent patent processus vaginalist (PPV). However, there is a lack of literature regarding the natural progression of PPVs in the absence of symptomatic hernias. This knowledge gap results in inconclusive guidelines for managing incidentally discovered PPVs or those found on the contralateral side during inguinal hernia repair in children. 

This prospective observational study included 526 infants under 4 months across 9 centers from the Midwest Pediatric Surgery Consortium. Patients who underwent laparoscopic pyloromyotomy were evaluated for the presence of a PPV in their bilateral inguinal canals. If a PPV was noted, further detail of location, size, estimated depth, and presence of scrotal/labial insufflation was recorded. 

During initial surgery, there were a total of 283 (53.8%) PPVs identified, of which 132 (47%) were bilateral, 116 (41%) were only right sided, and 35 (12%) were only left sided. Patients with a PPV were significantly younger (1.1 months vs 1.3 months, p=0.02), weighed less (3.76 kg vs 3.9 kg, p=0.03), were more commonly male (88% vs 75%, p<0.001), and had a lower gestational age (38 weeks vs 39 weeks (p=0.003). 

This study is ongoing with the intention to follow patients annually until 18 years old. At the time of interim analysis, 246 patients had reached at least one year of study enrollment. At 1-year follow up, 130/219 (59%) patients responded, with 3 reporting development of an inguinal hernia, all of which were managed operatively. At 2-year follow up, 64/151 (42%) responded, with no inguinal hernias reported. At 3-year follow up, 36/77 (47%) responded with no inguinal hernias reported. 22 patients have reached the 4-year follow up milestone so far, of which 16 (73%) had no reports of inguinal hernias. 

The overall rate of inguinal hernias in the 246 PPVs discovered by the time of interim analysis was 1.2% (3/246), all of which, interestingly, occurred within the first 120 days after laparoscopic pyloromyotomy. This demonstrates that while the incidence of PPV during the first 4 months of life is high, the risk of developing a hernia or requiring repair is low. Some limitations of this study include the recruitment of a cohort of patients after detection of PPV during another surgery (retrospective), which means the reported incidence of PPV is likely artificially inflated. Additionally, similar studies have shown that patients ultimately needing hernia repair were in their teens, suggesting that the relatively short-term interim analysis of only 4 years is not yet long enough to capture the full range of pathology. Long-term follow-up of this cohort will further establish the subsequent natural history of development of inguinal hernia in infants born with a PPV.

Bottom line: This observational study showed that while patent processus vaginalis may be prevalent among infants, most will never become clinically relevant or require intervention. 

This article describes the development of a novel machine-learning algorithm that closely predicts firearm violence in the urban United States (US) based on social, structural, and geospatial determinants of health.

Summary: In the US, firearm violence is a persistent health crisis, resulting in nearly 20,000 deaths per year and even greater incidence of injury. National data on firearm violence is, however, incredibly heterogenous and difficult to access, limiting development of prevention strategies and targeted resource allocation. This study sought to develop a tool to predict urban communities at highest risk of firearm violence using a machine learning algorithm. The goal was to create a tool is designed to use certain community characteristics to predict violence, allowing for more generalized use.

The study cohort involved 64,909 shooting incidents (both fatal and nonfatal) from eight US cities (Boston, Baltimore, Chicago, Cincinnati, Los Angeles, New York City, Philadelphia, and Rochester). Self-inflicted and accidental shootings were excluded. Latitude and longitude of each shooting incident was geocoded into 3,962 census tracts. The authors then chose 30 population characteristics to include in the model based on literature review and established public health principles on social and structural determinants of health; this prediction model was named the Firearm Violence Vulnerability Index (FVVI). The model’s primary outcome was shooting rate per 1,000 people within a census tract. The study cohort was split into a training group, and a validation group, with Chicago data withheld for use as a final model accuracy test.

A total of 64,909 shooting incidents in 3,962 census tracts were used to develop the model. A total of 3,169 census tracts were used in the training set and 793 in the validation set; in the test set, there were 14,898 shooting incidents in 776 census tracts.

Interestingly, the three population characteristics with the greatest impact on accuracy and permutation feature importance were (1) historical third-grade math scores of adults ~30 years of age, (2) percentage of parents incarcerated during their childhood, and (3) vacant housing units. Using the test set (Chicago), FVVI had a high predictive ability for shooting incidence per 1,000 people in a census tract, with a mean Poisson deviance of 2.29 and goodness of fit, D2 , of 0.77. They found that an FVVI value of 0.7 or higher appears to confer a notable increase in the risk of shooting incidents within a census tract. 

Overall, the development of the FVVI further highlights the role of systemic and structural inequities in driving urban firearm violence. A notable strength of the study is its use of both nonfatal and fatal shooting incidents and the use of 8 different US cities. However, the lack of inclusion of data from southern and midwestern cities from the training group (likely due to a lack of availability) could potentially limit the generalizability of this tool.

Bottom line: The FVVI, a machine-learning algorithm that predicts firearm violence within urban US census tracts, is a promising instrument that could be used for targeted violence prevention.

This retrospective study assesses post-transplant survival outcomes among liver transplant recipients following a 2017 Organ Procurement and Transplantation Network (OPTN) policy revision aimed at minimizing unnecessary simultaneous liver-kidney (SLK) transplants. The authors find that the policy did not adversely affect overall post-transplant survival; however, a significant survival reduction was noted among African American patients post-policy implementation.

Summary: In 2002, following the adoption of the MELD score for liver allocation, there was a notable rise in the number of SLKs; this increase was driven by the incorporation of serum creatinine into the MELD score, leading to the prioritization of liver transplant candidates who have both acute and chronic kidney injury. Therefore, in 2017, OPTN modified the criteria for SLK allocation, aiming to reduce the number of unnecessary procedures. In addition to limiting the number of kidney transplants for liver transplant patients in general, they also added a “safety net” for liver transplant patients still requiring dialysis or experience renal dysfunction one year post liver transplant, in which they have priority access to kidney transplants if needed. 

To study the effect of this revision in the policy, the authors performed a retrospective cohort study which including 109,626 adult patients listed for first-time deceased donor liver transplant, either for SLK or liver transplant alone (LTA), from 2013-2020. The outcome of interest was the impact of allocation policy on posttransplant survival. Using propensity score matching and instrumental variable analysis, they matched 319 SLK recipients with sustained acute kidney injury (sAKI) pre-policy (who would not have met criteria for SLK post-policy change) to 638 LTA patients with sustained acute kidney injury (sAKI) post-policy (who would have been eligible for SLK pre-policy change).

Overall, they found no significant difference in one-year and three-year post-transplant survival between SLK and LTA cohorts (87% vs 89% and 81% vs 80%, p = 0.9). However, a marked decrease in survival of African American patients post-policy was observed (89% vs 83% at one year; 87% vs 61% at three years; p = 0.03). A simulation model implementing a race-neutral eGFR calculation generated survival outcomes without racial disparity (p = 0.17), supporting OPTN's 2022 adoption of race-neutral eGFR. In all, this study found that the 2017 policy revision successfully reduced the number of SLKs while avoiding adverse effects on post-transplant survival in the overall population, while recognizing a notable survival decline among African American patients with sAKI. 

This study is constrained by the OPTN/UNOS dataset's limited patient-level data, center-specific propensity scores used for cohort matching, and limited sample size. The date range was deliberately chosen to exclude major confounding factors including the Share 35 policy, FDA approval of novel HCV antivirals, and the COVID-19 pandemic. 

Bottom Line: The revised 2017 OPTN policy effectively reduced the number of unwarranted SLK procedures without compromising the overall survival rate post-liver transplant. However, the survival rate for African American patients post-policy dropped significantly. The recent UNOS/OPTN adoption of the race-neutral 2021 CKD-EPI eGFR calculation is poised to address this gap, underscoring the ongoing need for policy evaluation and refinement to ensure equitable outcomes for all patients.