Ultrasound-Guided Regional Anesthesia of the Femoral Nerve in the Pediatric Emergency Department.

OBJECTIVES: Femur fractures are painful, and use of systemic opioids and other sedatives can be dangerous in pediatric patients. The fascia iliaca compartment nerve block and femoral nerve block are regional anesthesia techniques to provide analgesia by anesthetizing the femoral nerve. They are widely used in adult patients and are associated with good effect and reduced opioid use. Ultrasound (US) guidance of nerve blocks can increase their safety and efficacy. We sought to report on the use and safety of US-guided regional anesthesia of the femoral nerve performed by emergency physicians for femur fractures in 6 pediatric emergency departments. METHODS: Records were queried at 6 pediatric EDs across North America to identify patients with femur fractures managed with US-guided regional anesthesia of the femoral nerve between January 1, 2016, and May 1, 2021. Data were abstracted regarding demographics, injury pattern, nerve block technique, and analgesic use before and after nerve block. RESULTS: Eighty-five cases were identified. Median age was 5 years (interquartile range, 2-9 years). Most patients were male and had sustained blunt trauma (59% low-mechanism falls). Ninety-four percent of injuries were managed operatively. Most patients (79%) received intravenous opioid analgesia before their nerve block. Ropivacaine was the most common local anesthetic used (69% of blocks). No procedural complications or adverse effects were identified. CONCLUSIONS: Ultrasound-guided regional anesthesia of the femoral nerve is widely performed and can be performed safely on pediatric patients by emergency physicians and trainees in the pediatric emergency department.

Multi-compartment mesenchymal tissue segmentation in pelvic MRI examinations of women: Anthropomorphic and clinical correlations.

AIM: To investigate the reliability of multicompartmental volumetric mesenchymal segmentations on MRI and their correlations with anthropomorphic and clinical parameters. MATERIALS AND METHODS: A consecutive series of middle-age (35-50 year old) female volunteers with variable body mass index (BMI) and MRI scans performed as a part of the Dallas Heart Study were included. A semi-automatic segmentation tool was used to partition different mesenchymal tissues- fat, muscle, and bone on MRI of pelvis. Total volumes of each compartment were calculated and compared between overweight/obese (BMI> = 25 kg/m2) and non-obese (BMI < 25 kg/m2) groups, and with physical performance measurements, i.e. mean activity counts per minute (MVPA) and cardiorespiratory fitness (CRF) estimated by submaximal treadmill test (TT). Kruskal Wallis, Mann-Whitney U test, intraclass correlation coefficient (ICC) and Spearman correlations were used. P value <0.05 was considered statistically significant. RESULTS: There were statistically significant positive correlations between fat volume and BMI (p < 0.0001), muscle volume and height (p = 0.03), and bone volume and height (p < 0.0001). Significant inverse correlations were found between bone volume and BMI (p = 0.002). Fair to good interobserver reliability was seen with muscle and fat volumes (ICC = 0.43-0.64) and excellent reliability was seen with bone volumes (ICC = 0.78-0.79). Statistically significant inverse correlations were found between MVPA and age (p = 0.01), and TT with BMI and weight (p = 0.01, 0.03). CONCLUSION: Multi-compartment mesenchymal tissue volume quantification on pelvic MRI is reliable in females. Inverse correlation of bone volume with BMI has potential implications for future risk of fracture.

Multi-parametric muscle and fat correlation of computed tomography parameters to outcomes in a total hip arthroplasty population.

BACKGROUND: Cross-sectional imaging is not currently used in planning Total Hip Arthroplasty (THA). The aim of our study is to determine correlations between CT parameters and outcomes following THA. METHODS: A prospective registry of patients who underwent total joint arthroplasty was reviewed for patients who: (1) underwent THA, (2) had a CT between 1 year before and 6 months after surgery, and (3) completed perioperative WOMAC and Harris Hip Score (HHS) questionnaires. Two readers measured CT parameters, yielding mean Hounsfield Units, area, average diameter, and perimeter of the psoas major, gluteus medius and minimus muscles. A segmentation algorithm determined visceral and subcutaneous fat area, and waist circumference. ICC was calculated for each measurement to examine inter-reader agreement. Regression analyses were performed to select measurements with most impact on outcome scores. RESULTS: Twenty-eight patients met inclusion criteria (17 female, 11 male), having mean (+/- standard deviation) age of 54.4 +/- 14.8 years and BMI 29.0 +/- 6.3 kg/m2. Correlations were found between HHS and age (0.650, p = 0.018), height (-1.263, p = 0.009), visceral-to-subcutaneous fat area ratio at the psoas level (0.511, p = 0.018), and waist circumference at the psoas level (1.759, p = 0.002). Inter-reader analysis showed ICC > 0.850 for all measurements. CONCLUSION: Age and height, as well as CT-derived visceral-to-subcutaneous fat area ratio and waist circumference significantly correlate with postsurgical HHS scores following THA. Our study suggests that parameters derived from cross-sectional CT imaging can be useful additional preoperative planning tool for THA.

Tumor segmentation of whole-body magnetic resonance imaging in neurofibromatosis type 1 patients: tumor burden correlates.

OBJECTIVE: Segmentation of whole-body MRI (WBMRI) to assess the feasibility, quantitate the total tumor volume (tumor burden) in patients with neurofibromatosis type 1 (NF1) and examine associations with demographic, disease-related and anthropomorphic features. METHODS: A consecutive series of patients with NF1 underwent WBMRI and were reviewed for tumors. Tumors were segmented using a semiautomated software-based tool. Tumors were classified as superficial or deep and discrete or plexiform. Segmentation times were recorded. Segmentation yielded the quantity and tumor burden of superficial, internal and plexiform tumors. Correlations between segmentation data and demographic, disease-related and anthropomorphic features were examined. RESULTS: Fifteen patients were evaluated (42.3 ± 13.6 years, 10 female, 5 male). Segmentation times were a median of 30 min and yielded 2,328 tumors (1,582 superficial, 746 internal and 23 plexiform). One tumor was malignant. Tumor counts ranged from 14 to 397. Tumor burden ranged from 6.95 cm3 to 571 cm3. Individual tumor volume ranged from 0.0120 cm3 to 298 cm3. Significant correlation was found between the total volume of superficial tumors and height (ρ = 0.5966, p < 0.02). Male patients had higher overall tumor burdens (p < 0.05) and higher superficial tumor burden (p < 0.03). Patients with negative family history had more tumors (p < 0.05). CONCLUSION: Segmentation of WBMRI in patients with NF1 is feasible and elucidates meaningful relationships among disease phenotype, anthropomorphic and demographic features.

Using electrophoretic mobility shift assays to measure equilibrium dissociation constants: GAL4-p53 binding DNA as a model system.

An undergraduate biochemistry laboratory experiment is described that will teach students the practical and theoretical considerations for measuring the equilibrium dissociation constant (K(D) ) for a protein/DNA interaction using electrophoretic mobility shift assays (EMSAs). An EMSA monitors the migration of DNA through a native gel; the DNA migrates more slowly when bound to a protein. To determine a K(D) the amount of unbound and protein-bound DNA in the gel is measured as the protein concentration increases. By performing this experiment, students will be introduced to making affinity measurements and gain experience in performing quantitative EMSAs. The experiment describes measuring the K(D) for the interaction between the chimeric protein GAL4-p53 and its DNA recognition site; however, the techniques are adaptable to other DNA binding proteins. In addition, the basic experiment described can be easily expanded to include additional inquiry-driven experimentation. © 2012 by The International Union of Biochemistry and Molecular Biology.