Chronic thoracic pain after cardiac surgery: role of inflammation and biomechanical sternal stability.

Introduction: The pathogenesis of chronic chest pain after cardiac surgery has not been determinate. If left untreated, postoperative sternal pain reduces the quality of life and patient satisfaction with cardiac surgery. The purpose of the study was to examine the effect of chest inflammation on postoperative pain, risk factors for chronic pain after cardiac surgery and to explore how chest reconstruction was associated with the intensity of pain. Methods: The authors performed a study of acute and chronic thoracic pain after cardiac surgery in patients with and without sternal infection and compared different techniques for chest reconstruction. 42 high-risk patients for the development of mediastinitis were included. Patients with mediastinitis received chest reconstruction (group 1). Their demographics and risk factors were matched with no-infection patients with chest reconstruction (group 2) and subjects who underwent conventional sternal closure (group 3). Chronic pain was assessed by the numeric rating scale after surgery. Results: The assessment of the incidence and intensity of chest pain at 3 months post-surgery demonstrated that 14 out of 42 patients across all groups still experienced chronic pain. Specifically, in group 1 with sternal infection five patients had mild pain, while one patient experienced mild pain in group 2, and eight patients in group 3. Also, follow-up results indicated that the highest pain score was in group 3. While baseline levels of cytokines were increased among patients with sternal infection, at discharge only the level of interleukin 6 remained high compared to no infection groups. Compared to conventional closure, after chest reconstruction, we found better healing scores at 3-month follow-up and a higher percentage of patients with the complete sternal union. Conclusions: Overall, 14 out of 42 patients have chronic pain after cardiac surgery. The intensity of the pain in mediastinitis patients significantly decreased at 3 months follow-up after chest reconstruction. Thus, post-surgery mediastinitis is not a determining factor for development the chronic chest pain. There is no correlation between cytokines levels and pain score except interleukin 6 which remains elevated for a long time after treatment. Correlation between sternal healing score and chronic chest pain was demonstrated.

Challenges and Opportunities for the Use of Patient-Reported Outcome Measures in Orthopaedic Pediatric and Sports Medicine Surgery.

Patient-reported outcome measures (PROMs) are essential tools in assessing treatment response, informing clinical decision making, driving healthcare policy, and providing important prognostic data regarding patient health status change. These tools become essential in orthopaedic disciplines, such as pediatrics and sports medicine, given the diversity of patient populations and procedures. However, the creation and routine administration of standard PROMs alone do not suffice to appropriately facilitate the aforementioned functions. Indeed, both the interpretation and optimal application of PROMs are essential to provide to achieve greatest clinical benefit. Contemporary developments and technologies surrounding PROMs may help augment this benefit, including the application of artificial intelligence, novel PROM structure with improved interpretability and validity, and PROM delivery methods that provide increased access to patients resulting in greater compliance and data acquisition yields. Despite these exciting innovations, several challenges remain in this realm that must be addressed to continue to advance the clinical usefulness and subsequent benefit of PROMs. This review will highlight the opportunities and challenges surrounding contemporary PROM use in the orthopaedic subspecialties of pediatrics and sports medicine.

Multivariable regression: understanding one of medicine's most fundamental statistical tools.

Multivariable regression is a fundamental tool that drives observational research in orthopaedic surgery. However, regression analyses are not always implemented correctly. This study presents a basic overview of regression analyses and reviews frequent points of confusion. Topics include linear, logistic, and time-to-event regressions, causal inference, confounders, overfitting, missing data, multicollinearity, interactions, and key differences between multivariable versus multivariate regression. The goal is to provide clarity regarding the use and interpretation of multivariable analyses for those attempting to increase their statistical literacy in orthopaedic research.

Unsupervised machine learning methods and emerging applications in healthcare.

Unsupervised machine learning methods are important analytical tools that can facilitate the analysis and interpretation of high-dimensional data. Unsupervised machine learning methods identify latent patterns and hidden structures in high-dimensional data and can help simplify complex datasets. This article provides an overview of key unsupervised machine learning techniques including K-means clustering, hierarchical clustering, principal component analysis, and factor analysis. With a deeper understanding of these analytical tools, unsupervised machine learning methods can be incorporated into health sciences research to identify novel risk factors, improve prevention strategies, and facilitate delivery of personalized therapies and targeted patient care.Level of evidence: I.

Choosing the appropriate measure of central tendency: mean, median, or mode?

Mean, median, and mode are among the most basic and consistently used measures of central tendency in statistical analysis and are crucial for simplifying data sets to a single value. However, there is a lack of understanding of when to use each metric and how various factors can impact these values. The aim of this article is to clarify some of the confusion related to each measure and explain how to select the appropriate metric for a given data set. The authors present this work as an educational resource, ensuring that these common statistical concepts are better understood throughout the Orthopedic research community.

Fragility Part I: a guide to understanding statistical power.

The aim of this paper is to close the knowledge-to-practice gap around statistical power. We demonstrate how four factors affect power: p value, effect size, sample size, and variance. This article further delves into the advantages and disadvantages of a priori versus post hoc power analyses, though we believe only understanding of the former is essential to addressing the present-day issue of reproducibility in research. Upon reading this paper, physician-scientists should have expanded their arsenal of statistical tools and have the necessary context to understand statistical fragility.

External Validation of a Machine Learning Algorithm for Predicting Clinically Meaningful Functional Improvement After Arthroscopic Hip Preservation Surgery.

BACKGROUND: Individualized risk prediction has become possible with machine learning (ML), which may have important implications in enhancing clinical decision making. We previously developed an ML algorithm to predict propensity for clinically meaningful outcome improvement after hip arthroscopy for femoroacetabular impingement syndrome. External validity of prognostic models is critical to determine generalizability, although it is rarely performed. PURPOSE: To assess the external validity of an ML algorithm for predicting clinically meaningful improvement after hip arthroscopy. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: An independent hip preservation registry at a tertiary academic medical center was queried for consecutive patients/athletes who underwent hip arthroscopy for femoroacetabular impingement syndrome between 2015 and 2017. By assuming a minimal clinically important difference (MCID) outcome/event proportion of 75% based on the original study, a minimum sample of 132 patients was required. In total, 154 patients were included. Age, body mass index, alpha angle on anteroposterior pelvic radiographs, Tönnis grade and angle, and preoperative Hip Outcome Score-Sports Subscale were used as model inputs to predict the MCID for the Hip Outcome Score-Sports Subscale 2 years postoperatively. Performance was assessed using identical metrics to the internal validation study and included discrimination, calibration, Brier score, and decision curve analysis. RESULTS: The concordance statistic in the validation cohort was 0.80 (95% CI, 0.71 to 0.87), suggesting good to excellent discrimination. The calibration slope was 1.16 (95% CI, 0.74 to 1.61) and the calibration intercept 0.13 (95% CI, -0.26 to 0.53). The Brier score was 0.15 (95% CI, 0.12 to 0.18). The null model Brier score was 0.20. Decision curve analysis revealed favorable net treatment benefit for patients with use of the algorithm as compared with interventional changes made for all and no patients. CONCLUSION: The performance of this algorithm in an independent patient population in the northeast region of the United States demonstrated superior discrimination and comparable calibration to that of the derivation cohort. The external validation of this algorithm suggests that it is a reliable method to predict propensity for clinically meaningful improvement after hip arthroscopy and is an essential step forward toward introducing initial use in clinical practice. Potential uses include integration into electronic medical records for automated prediction, enhanced shared decision making, and more informed allocation of resources to optimize patient outcomes.

Picking apart p values: common problems and points of confusion.

Due to its frequent misuse, the p value has become a point of contention in the research community. In this editorial, we seek to clarify some of the common misconceptions about p values and the hazardous implications associated with misunderstanding this commonly used statistical concept. This article will discuss issues related to p value interpretation in addition to problems such as p-hacking and statistical fragility; we will also offer some thoughts on addressing these issues. The aim of this editorial is to provide clarity around the concept of statistical significance for those attempting to increase their statistical literacy in Orthopedic research.

Efficient cardiac gene transfer and early-onset expression of a synthetic adeno-associated viral vector, Anc80L65, after intramyocardial administration.

OBJECTIVE: Gene therapy is a promising approach in the treatment of cardiovascular diseases. Preclinical and clinical studies have demonstrated that adeno-associated viral vectors are the most attractive vehicles for gene transfer. However, preexisting immunity, delayed gene expression, and postinfection immune response limit the success of this technology. The aim of this study was to investigate the efficacy of the first synthetic adeno-associated viral lineage clone, Anc80L65, for cardiac gene therapy. METHODS: By combining 2 different reporter approaches by fluorescence with green fluorescent protein and bioluminescence (Firefly luciferase), we compared transduction efficiency of Anc80L65 and adeno-associated virus, serotype 9 in neonatal rat cardiomyocytes ex vivo and rat hearts in vivo after intramyocardial and intracoronary administration. RESULTS: In cardiomyocytes, Anc80L65 provided a green fluorescent protein expression of 28.9% (36.4 ± 3.34 cells/field) at 24 hours and approximately 100% on day 7. In contrast, adeno-associated virus, serotype 9 green fluorescent protein provided minimal green fluorescent protein expression of 5.64% at 24 hours and 11.8% on day 7. After intramyocardial injection, vector expression peaked on day 7 with Anc80L65; however, with adeno-associated virus, serotype 9 the peak expression was during week 6. Administration of Anc80L65 demonstrated significantly more efficient expression of reporter gene than after adeno-associated virus, serotype 9 at 6 weeks (6.81 ± 0.64 log10 gc/100 ng DNA vs 6.49 ± 0.28 log10 gc/100 ng DNA, P < .05). These results were consistent with the amount of genome copy per cell observed in the heart. CONCLUSIONS: Anc80L65 vector allows fast and robust gene transduction compared with adeno-associated virus, serotype 9 vector in cardiac gene therapy. Anc80L65 did not adversely affect cardiac function and caused no inflammatory response or toxicity.

Inflammatory Responses with Left Ventricular Compromise after Induction of Myocardial Infarcts in Sheep (Ovis aries).

Ischemic myocardial disease is a major cause of death among humans worldwide; it results in scarring and pallor of the myocardium and triggers an inflammatory response that contributes to impaired left ventricular function. This response includes and is evidenced by the production of several inflammatory cytokines including TNFα, IL1ß, IL4, IFNγ, IL10 and IL6. In the current study, myocardial infarcts were induced in 6 mo old male castrated sheep by ligation of the left circumflex obtuse marginal arteries (OM 1 and 2). MRI was used to measure parameters of left ventricular function that include EDV, ESV, EF, SVI, dp/dt max and dp/dt min at baseline and at 4 wk and 3 mo after infarct induction. We also measured serum concentrations of an array of cytokines. Postmortem histologic findings corroborate the existence of left ventricular myocardial injury and deterioration. Our data show a correlation between serum cytokine concentrations and the development of myocardial damage and left ventricular functional compromise.

Use of longitudinal rigid sternal fixation in prevention and treatment of wound complications among high-risk patients after cardiac surgery.

BACKGROUND: Traditionally, wire cerclage closure has been used to reapproximate the sternum after cardiac surgery. Recent evidence suggests that rigid sternal fixation may reduce the risk of wound complications. The aim of this study was to analyze our 10-year experience with longitudinal rigid sternal fixation (LRSF) for prevention and treatment of wound complications in high-risk patients. METHODS: We reviewed data from cardiac surgical database of patients who underwent LRSF, and compared their outcomes with conventional wire cerclage closure (CWS). Among these 319 patients were designated as having high-risk for the development of deep wound complications and received primary LRSF (treatment group). We matched their outcomes with 319 patients who met indications for LRSF however, underwent standard closure with CWC (control group). RESULTS: Both groups were comparable regarding preoperative and intraoperative variables. The benefit observed among matched patients who had undergone LRSF was largely driven by a decreased rate of deep wound infections (0.63% vs. 3.45% vs., p < .01), 30-day mortality (1.57% vs. 5.96%) and hospital length (8.2 vs. 11.7 days) p < .05, respectively. A multivariate logistic regression analysis found four independent risk factors for the development of sternal dehiscence. Sternal healing evaluated by computerized tomography scan using 6-point scale at 3 months after surgery was superior in LRSF patients. Pain scores were significantly lower in LRSF patients as well. CONCLUSIONS: In patients with an increased risk for sternal instability and wound infections after cardiac surgery, sternal reconstruction using LRSF is an effective technique to stabilize sternum for preventive and treatment purposes.

Median Sternotomy After Sternal Reconstruction With Bilateral Longitudinal Plating in a Patient With Osteoporosis.

In recent decades, new information has arisen regarding sternal healing and extended indications for using rigid plate fixation in patients during cardio-thoracic procedures. Three randomized controlled multicenter clinical trials recently demonstrated positive results after rigid plate fixation, including reduced sternal complications and decreased length of hospital stay. However, redo-sternotomy after sternal reconstruction utilizing rigid fixation has not been previously delineated in surgical literature. This case highlights the technical challenges of performing a median sternotomy for cardiac surgery after sternal reconstruction with bilateral longitudinal plating.

Single-stage hybrid repair of a ruptured Kommerell diverticulum associated with dextrorotation, bovine arch, and bicuspid aortic valve.

BACKGROUND: A strategy for the surgical repair of ruptured Kommerell diverticulum has not yet been established. The aim of this study is to demonstrate that this entity could be associated with a number of other cardiac anomalies and this lesion can be successfully treated by a hybrid approach. CASE PRESENTATION: The patient, with a combination of ruptured Kommerell diverticulum, dextrorotation, bovine arch, and bicuspid aortic valve, underwent emergency surgery. A single stage hybrid surgical/endovascular repair including subclavian artery revascularization, aortic resection with open proximal anastomosis under circulatory arrest, endovascular stenting, and valve repair was performed. Histological studies indicated the presence of the aortic wall media degeneration. Postoperative course was uneventful and patient is free of symptoms during 2-year follow up. CONCLUSIONS: Less invasive hybrid technique is safe and effective treatment option. Accumulated knowledge of Kommerell diverticulum has lead to understanding the best clinical treatment for this complicated aortic anomaly.

Right Atrial Anomalous Muscle Bundle Presenting with Acute Superior Vena Cava Syndrome and Pulmonary Embolism: Surgical Management.

BACKGROUND: An anomalous muscle bundle (AMB) crossing the right atrial cavity represents a pathologic finding with unproved clinical significance. This congenital anomaly may be difficult to recognize via echocardiography and could be confused with other intracavitary lesions. METHODS: We report the case of a 53-year-old woman presented to the cardiovascular service with acute superior vena cava (SVC) syndrome and submassive pulmonary embolism. RESULTS: The patient underwent venography, confirming SVC stenosis. A ventilation/perfusion lung scan showed 2 sizable perfusion defects because of pulmonary embolism. Magnetic resonance imaging and echocardiography imaging demonstrated a right atrium (RA) mass. Surgery was then carried out using standard cardiopulmonary bypass; the right atrial muscle bundle was excised, and SVC reconstruction was performed. The patient was discharged uneventfully and remains symptom-free at 2-year follow-up. CONCLUSIONS: In cases of nonmalignant pathology of SVC syndrome, appropriate studies should be conducted to exclude potential congenital abnormalities such as this AMB in the RA. Open-heart surgery is a viable treatment option in select cases.