Impact of radiation dose distribution on nutritional supplementation needs in head and neck cancer radiotherapy: a voxel-based machine learning approach.

Objectives: To investigate the relationship between nutritional supplementation and radiation dose to the pharyngeal constrictor muscles and larynx for head and neck (HN) cancer patients undergoing radiotherapy. Methods: We retrospectively analyzed radiotherapy (RT) dose for 231 HN cancer patients, focusing on the pharyngeal constrictors and larynx. We defined nutritional supplementation as feeding tube utilization or >10% weight loss from baseline within 90 days after radiotherapy completion. Using deformable image registration (DIR), we mapped each patient's anatomical structures to a reference coordinate system, and corresponding deformations were applied to dose matrices. Voxel doses were utilized as features for ridge logistic regression models, optimized through 5-fold cross-validation. Model performance was assessed with area under the curve of a receiver operating curve (AUC) and F1 score. We built and compared models using 1) pharyngeal constrictor voxels, 2) larynx voxels, 3) clinical factors and mean regional dose metrics, and 4) clinical factors and dose-volume histogram metrics. Test set AUCs were compared among the models, and feature importance was evaluated. Results: DIR of the pharyngeal constrictors and larynx yielded mean Dice coefficients of 0.80 and 0.84, respectively. Pharyngeal constrictors voxels and larynx voxel models had AUC of 0.88 and 0.82, respectively. Voxel-based dose modeling identified the superior to middle regions of the pharyngeal constrictors and the superior region of larynx as most predictive of feeding tube use/weight loss. Univariate analysis found treatment setting, treatment laterality, chemotherapy, baseline dysphagia, weight, and socioeconomic status predictive of outcome. An aggregated model using mean doses of pharyngeal constrictors and larynx subregions had an AUC of 0.87 and the model using conventional DVH metrics had an AUC of 0.85 with p-value of 0.04. Feature importance calculations from the regional dose model indicated that mean doses to the superior-middle pharyngeal constrictor muscles followed by mean dose to the superior larynx were most predictive of nutritional supplementation. Conclusions: Machine learning modeling of voxel-level doses enables identification of subregions within organs that correlate with toxicity. For HN radiotherapy, doses to the superior-middle pharyngeal constrictors are most predictive of feeding tube use/weight loss followed by the doses to superior portion of the larynx.

Ultrasound diagnosis of Mondor's disease involving the superficial scrotal veins: Unveiling a rare mimicker of acute scrotal emergencies.

We describe a rare case of Mondor disease of the superficial scrotal veins, which can clinically mimic acute testicular pathologies such as testicular torsion or epididymo-orchitis, and highlight the value of grayscale/Doppler ultrasound examination in distinguishing these entities, which have different management implications.

Predictors of mortality within the first year post-hepatectomy for hepatocellular carcinoma.

BACKGROUND: Hepatic resection (HR) for hepatocellular carcinoma (HCC) is safe with good perioperative and long-term oncologic outcomes. There is a paucity of data with regards to intermediate-term outcomes (i.e., beyond 90-day and within 1-year mortality). This paper studies the risk factors for within 1-year mortality after elective HR with curative intent in patients with HCC. METHODS: An audit of patients who underwent curative HR for HCC from January 2007 to April 2016 was conducted. Univariate and multivariate analysis were sequentially performed on perioperative variables using Cox-regression analysis to identify factors predicting intermediate-term outcomes defined as within 1-year mortality. Kaplan-Meier survival curves and hazard ratios were obtained. RESULTS: Three hundred forty-eight patients underwent HR during the study period and 163 patients had curative hepatectomy for HCC. Fifteen patients (9.2%) died within 1-year after HR. Multivariate analysis identified Child-Pugh class B/C (HR 5.5, p = 0.035), multinodularity (HR 7.1, p = 0.001), macrovascular invasion (HR 4.2, p = 0.04) postoperative acute renal failure (HR 5.8, p = 0.049) and posthepatic liver failure (HR 9.6, p = 0.009) as significant predictors of 1-year mortality. CONCLUSION: One-year mortality following HR for HCC remains high and can be predicted preoperatively by multinodularity, Child-Pugh class, and macrovascular invasion. Postoperative acute renal failure and liver failure are associated with 1-year mortality.

Perceptions of Singaporeans towards informed consent: a cross-sectional survey.

INTRODUCTION: In a patient-centric health system, it is essential to know patients' views about informed consent. The objective of this study was to understand the perceptions of the local population regarding informed consent. METHODS: Spanning across six weeks from January 2016 to March 2016, a cross-sectional survey of adults attending General Surgery outpatient clinics at Tan Tock Seng Hospital was performed. Sociodemographic data, lifestyle and health-related information, perception and purpose of consent forms, and decision-making preferences were studied. RESULTS: 445 adults participated in the survey. Most participants were below 40 years old (n = 265, 60.1%), female (n = 309, 70.1%) and degree holders (n = 196, 44.4%). 56.9% of participants wanted to know every possible risk, while 28.3% wanted to know common and serious risks. On multivariate analysis, age (age 61-74 years: odds ratio [OR] 11.1, 95% confidence interval [CI] 2.2-56.1, p = 0.004; age > 75 years: OR 22.2, 95% CI 1.8-279.1, p = 0.017) was a predictor of not wanting to know any risks. Age also predicted risk of disclosure for death (age 61-74 years: OR 13.4, 95% CI 4.2-42.6, p < 0.001; age > 75 years: OR 32.0, 95% CI 4.5-228.0, p = 0.001). Most participants (48.1%) preferred making shared decisions with doctors, and an important predictor was employment status (OR = 4.8, 95% CI 1.9-12.2, p = 0.001). CONCLUSION: Sociodemographic factors and educational level influence decision-making, and therefore, the informed consent process should be tailored for each patient.

How efficacious are Octreotide and Somatostatin in the management of chylothorax in congenital cardiac surgical patients?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was how efficacious are Octreotide and Somatostatin in the management of chylothorax in congenital cardiac surgical patients. Altogether >55 papers were found using the reported search, of which 8 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The comparative data on LOS and chylothorax duration are mixed though interpretation is difficult since Octreotide has been instituted belatedly from the onset of chylothorax in multiple instances. There is also preliminary evidence to suggest that responders to Somatostatin and Octreotide are affected by single-ventricle physiology and CVP levels. Meanwhile, non-responders tend to have higher mortality and may merit earlier surgical intervention. The included studies thus far have significant limitations such as low-level evidence study design, selection bias, variability in duration and dosage of therapy and heterogenous comparative arms. Notwithstanding these limitations, Octreotide has shown to be an useful adjunct treatment in reducing chylothorax volume especially in patients with higher output chylothorax (>40 ml/kg/h) after the failure of conservative management.

Behind the Façade: Robotic-Assisted Resection of a Diaphragmatic Osteochondroma.

Neoplasms arising from the diaphragm are not typically seen in clinical practice, though they may inflict significant morbidity and mortality. In the realm of thoracic surgery, osteochondromas are only encountered at the thoracic wall or vertebra. In this study, we describe a case of an osteochondroma arising from the diaphragm masquerading as a malignant lesion. The tumor was resected via robotic-assisted means and the patient was discharged with no complications.

Inferior vena cava leiomyosarcoma in an octogenerian.

Inferior Vena Cava (IVC) leiomyosarcoma (LM) is a rare malignancy of mesenchymal origin with an incidence of 1/100,000. We present an 82-year-old lady with a past history of open cholecystectomy who presented with a large indeterminate mass on abdominal imaging. Open resection of the mass was performed and histology with immunohistochemical staining revealed leiomyosarcoma. She received adjuvant radiotherapy and remained disease free 4 years after.

The effect of inlet and outlet boundary conditions in image-based CFD modeling of aortic flow.

BACKGROUND: Computational modeling of cardiovascular flow is a growing and useful field, but such simulations usually require the researcher to guess the flow's inlet and outlet conditions since they are difficult and expensive to measure. It is critical to determine the amount of uncertainty introduced by these assumptions in order to evaluate the degree to which cardiovascular flow simulations are accurate. Our work begins to address this question by examining the sensitivity of flow to several different assumed velocity inlet and outlet conditions in a patient-specific aorta model. METHODS: We examined the differences between plug flow, parabolic flow, linear shear flows, skewed cubic flow profiles, and Womersley flow at the inlet. Only the shape of the inlet velocity profile was varied-all other parameters were identical among these simulations. Secondary flow in the form of a counter-rotating pair of vortices was also added to parabolic axial flow to study its effect on the solution. In addition, we examined the differences between two-element Windkessel, three element Windkessel and the outflow boundary conditions. In these simulations, only the outlet boundary condition was varied. RESULTS: The results show axial and in-plane velocities are considerably different close to the inlet for the cases with different inlet velocity profile shapes. However, the solutions are qualitatively similar beyond 1.75D, where D is the inlet diameter. This trend is also observed in other quantities such as pressure and wall shear stress. Normalized root-mean-square deviation, a measure of axial velocity magnitude differences between the different cases, generally decreases along the streamwise coordinate. The linear shear inlet velocity boundary condition and plug velocity boundary condition solution exhibit the highest time-averaged wall shear stress, approximately [Formula: see text] higher than the parabolic inlet velocity boundary condition. Upstream of 1D from the inlet, adding secondary flow has a significant impact on temporal wall shear stress distributions. This is especially observable during diastole, when integrated wall shear stress magnitude varies about [Formula: see text] between simulations with and without secondary flow. The results from the outlet boundary condition study show the Windkessel models differ from the outflow boundary condition by as much as [Formula: see text] in terms of time-averaged wall shear stress. Furthermore, normalized root-mean-square deviation of axial velocity magnitude, a measure of deviation between Windkessel and the outflow boundary condition, increases along the streamwise coordinate indicating larger variations near outlets. CONCLUSION: It was found that the selection of inlet velocity conditions significantly affects only the flow region close to the inlet of the aorta. Beyond two diameters distal to the inlet, differences in flow solution are small. Although additional studies must be performed to verify this result, the data suggest that it is important to use patient-specific inlet conditions primarily if the researcher is concerned with the details of the flow very close to the inlet. Similarly, the selection of outlet conditions significantly affects the flow in the vicinity of the outlets. Upstream of five diameters proximal to the outlet, deviations between the outlet boundary conditions examined are insignificant. Although the inlet and outlet conditions only affect the flow significantly in their respective neighborhoods, our study indicates that outlet conditions influence a larger percentage of the solution domain.

Predicting morbidity of liver resection.

PURPOSE: Multiple models have attempted to predict morbidity of liver resection (LR). This study aims to determine the efficacy of American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) surgical risk calculator and the Physiological and Operative Severity Score in the enUmeration of Mortality and Morbidity (POSSUM) in predicting post-operative morbidity in patients who underwent LR. METHODS: A retrospective analysis was conducted on patients who underwent elective LR. Morbidity risk was calculated with the ACS-NSQIP surgical risk calculator and POSSUM equation. Two models were then constructed for both ACS-NSQIP and POSSUM-(1) the original risk probabilities from each scoring system and (2) a model derived from logistic regression of variables. Discrimination, calibration, and overall performance for ACS-NSQIP and POSSUM were compared. Sub-group analysis was performed for both primary and secondary liver malignancies. RESULTS: Two hundred forty-five patients underwent LR. Two hundred twenty-three (91%) had malignant liver pathologies. The post-operative morbidity, 90-day mortality, and 30-day mortality rate were 38.3%, 3.7%, and 2.4% respectively. ACS-NSQIP showed superior discriminative ability, calibration, and performance to POSSUM (p = 0.03). Hosmer-Lemeshow plot demonstrated better fit of the ACS-NSQIP model than POSSUM in predicting morbidity. CONCLUSION: In patients undergoing LR, the ACS-NSQIP surgical risk calculator was superior to POSSUM in predicting morbidity risk.

The comparative effects of high fat diet or disturbed blood flow on glycocalyx integrity and vascular inflammation.

BACKGROUND AND AIMS: Endothelial surface glycocalyx shedding plays a role in endothelial dysfunction and increases vessel wall permeability, which can lead to inflammation and atherogenesis. We sought to elucidate whether a high fat diet (HFD) or disturbed blood flow conditions, both of which are atherogenic risk factors, would contribute more detrimentally to pre-atherosclerotic loss of endothelial glycocalyx integrity and vascular inflammation. METHODS: Six to seven week-old C57BL/6-background apolipoprotein-E-knockout (ApoE-KO) male mice were either fed a chow diet, fed a modified Western HFD, and/or subjected to a partial left carotid artery (LCA) ligation procedure to induce disturbed blood flow patterns in the LCA. Mice were sacrificed after 1 week of experimental conditions. Both LCA and right carotid artery (RCA) vessels were dissected and preserved to compare glycocalyx coverage and thickness as well as macrophage accumulation in carotid arterial walls amongst and between cohorts. RESULTS: Glycocalyx coverage of the endothelium was significantly reduced in the LCAs of HFD fed mice when compared to the control. More significant reduction in glycocalyx coverage occurred in the LCAs of mice exposed to disturbed flow by partial LCA ligation when compared to the control. No differences were found in glycocalyx coverage of RCAs from all cohorts. Regarding inflammation, no difference in macrophage accumulation in carotid arterial walls was observed when comparing the LCAs and RCAs of control and HFD fed mice. However, macrophage infiltration in vessel walls showed a 20-fold increase in the LCAs exposed to disturbed flow following ligation, when compared to control LCAs, while no such statistical difference was observed between the RCAs of the group. CONCLUSIONS: In our mouse model, endothelial glycocalyx integrity was compromised more by disturbed blood flow patterns than by exposure of the carotid vessel to HFD conditions. The pathophysiological implications include endothelial dysfunction, which correlates to macrophage infiltration in vessel walls and promotes atherogenesis.

Cardiopulmonary bypass time: every minute counts.

BACKGROUND: This study was conducted to examine the impact of CPB times on postoperative outcomes. We sought to determine the optimum cut-offs of CPB per graft time and cumulative CPB time and their predictive accuracy for mortality in conjunction with EuroSCORE II. METHODS: The de-identified data of 1960 patients who had undergone isolated on-pump CABG from 2009 to 2014 were analyzed. The risk strata of cardiopulmonary bypass (CPB)/graft and cumulative CPB times, identified with a decision tree, were added into an augmented model for predicting short- and intermediate-term postoperative clinical events. RESULTS: Prolonged cumulative CPB time (>180 minutes) was significant in predicting mortality while adjusting for EuroSCORE II, postoperative complications, prolonged ICU stay and prolonged mechanical ventilation. Whereas prolonged CPB/graft time (>56 minutes) was marginally non-significant in terms of its direct effects, its indirect effect on mortality could be manifested through enhanced risks of complications, prolonged ICU stay (>48 hours) and prolonged mechanical ventilation (>24 hours). CONCLUSIONS: Prolonged CPB times could predict postoperative clinical events, in particular mortality. To minimize the occurrence of unfavorable adverse outcomes, it is recommended that the CPB/graft time and cumulative CPB time be kept below 56 minutes and 180 minutes respectively.