Model Setting and Interpretation of Results in Research Using Structural Equation Modeling: A Checklist with Guiding Questions for Reporting

PurposeThis study develops a checklist with guidelines for the methods and important factors to consider in research using structural equation modeling (SEM).MethodThe paper discusses the factors to consider in the process across the three stages of 1) model setting, 2) model evaluation and modification, and 3) interpretation and reporting of SEM-based studies.ResultsThe authors present a checklist for researchers during the stages of model setting, model evaluation and modification, result analysis, and reporting, along with examples of figures and tables with explanations.ConclusionA checklist will help to improve the reporting quality of SEM-based studies.     

Hypertensive Crisis during Microwave Ablation of Adrenal Neoplasms: A Retrospective Analysis of Predictive Factors

PurposeTo identify risk factors for hypertensive crisis (HC) during ultrasound-guided percutaneous microwave (MW) ablation of adrenal neoplasms.Materials and MethodsPatients who underwent MW ablation for adrenal tumors between April 2006 and November 2017 were retrospectively identified for this study (51 consecutive patients; 35 males, 16 females; mean age, 55 years; range, 15–85 years). A total of 77 MW ablation treatments were performed for 67 tumors (24 primary [9 pheochromocytomas, 8 adenomas, and 7 cortical carcinomas]; and 43 metastases [22 hepatocellular carcinoma, 8 renal cell carcinoma, 5 non-small cell lung cancer, 4 colorectal cancer, 3 liposarcoma, and 1 malignant fibrous histiocytoma]). The mean diameter of the adrenal tumors was 4.6 cm (range, 1.2–16.2 cm). Information about patient demographics, imaging studies, pathology and laboratory results, procedure records, and clinical outcomes was retrieved and analyzed. Statistical analysis was then performed to determine potential risk factors for HC.ResultsOf the 77 MW ablation procedures, HC occurred in 13 (16.9%). A significantly higher risk of HC was observed in patients with pheochromocytoma (odds ratio [OR], 9.037; 95% confidence interval [CI], 1.731–47.172; P = .009), body mass index <24 kg/m² (OR, 5.167; 95% CI, 1.060–25.194; P = .042), dominant tumor size ≤4.5 cm (OR, 4.023; 95% CI, 1.011–16.005; P = .048), and pre-procedural systolic blood pressure ≥130 mmHg (OR, 0.242; 95% CI, 0.068–0.861; P = .029).ConclusionHC can occur during MW ablation in patients with either primary or metastatic adrenal tumors. Pheochromocytoma, body mass index, tumor size, and pre-procedural systolic blood pressure appear to be significant risk factors for the occurrence of HC.     

Motor unit number index (MUNIX) in the quantitative assessment of severity and surgical outcome in cervical spondylotic amyotrophy

ObjectiveTo assess the feasibility of motor unit number index (MUNIX) in the quantitative assessment of the cervical spondylotic amyotrophy (CSA).MethodsMUNIX was recorded bilaterally on the abductor pollicis brevis, abductor digiti minimi, biceps brachii and middle deltoid in 41 normal controls and 47 patients with CSA (distal-type to proximal-type ratio: 25 to 22). Additionally, patients were assessed on handgrip strength (HGS), the disabilities of arm, shoulder and hand (DASH) and Medical Research Council (MRC) scales. These examinations were re-evaluated approximately 18 months after surgery in 37 of these CSA patients.ResultsMUNIX values were noticeably lower in the mainly affected muscles of CSA patients than those in controls (P < 0.05), and 49.0% (51/104) of the tested muscles with abnormal MUNIX measurements showed normal muscle strength. Significant correlations between MUNIX measurements and both DASH and MRC scores were observed in both CSA patient groups (P < 0.05). Postoperative longitudinal follow-up analysis identified significant increase in motor unit number in both CSA patient groups within approximately 18 months (P < 0.05), with or without improved measures of motor function.ConclusionsA significant reduction in MUNIX values related to motor impairment was observed in CSA patients, even in the subclinical stage. Compared to measures of motor function, the MUNIX measurements in the patients with CSA improved more noticeably after surgical intervention.SignificanceMUNIX may serve as an available supplementary test to quantitatively evaluate the motor dysfunction in CSA and to track its progression, that is complementary to conventional electromyography.     

A comparison of the academic impact of plastic surgery units in the United Kingdom and Ireland using bibliometric analysis

Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia.     

Re-engineering the interpretation of electronic fetal monitoring to identify reversible risk for cerebral palsy: a case control series

Background: Even key opinion leaders now concede that electronic fetal monitoring (EFM) cannot reliably identify fetal acidemia which many vouch as the only labor mediated pathophysiologic precursor for cerebral palsy (CP). We have developed the “Fetal Reserve Index” – an algorithm combining five dynamic components of EFM (1. Rate, 2. Variability, 3. Accelerations, 4. Decelerations, and 5. Excessive uterine activity) considered individually that are combined with the presence of: 6. maternal, 7. obstetrical, and 8. fetal risk factors.

Objective: Here, we compare this 8-point fetal reserve index (FRI) against the performance of ACOG monograph criteria and ACOG Category systems for predicting risk for both CP and the need for emergency operative delivery (EOD). We then studied how varied management for screen positives (Red zone-defined below) impacts the outcome of such cases.

Study design: Four hundred twenty term patients were studied: all entered labor with normal EFMs and no apparent cause of harm except events of labor and delivery. Sixty subsequently developed CP, and 360 were apparently normal controls. An FRI, normal on all eight parameters scored 100%, 4 of the 8 was 50%, etc. We divided cases into Green zone >50%, Yellow 50–26%, and Red ≤25%. An FRI in the Red zone was considered a positive screen. We then compared performance metrics for the three evaluation schemes and differences between controls that reached Red against those controls whose worst scores were Green/Yellow.

Results: For detection of injury during labor, the FRI performed much better than the ACOG Category criteria (sensitivity 28%), and Category III (45%) (p?Conclusions: FRI shows better discrimination for adverse fetal outcome and EOD than traditional EFM interpretation. The Category system is a very poor, subjective screening method as the vast majority of CP babies never reach the “action point” result of Category III. While reaching the Red zone does not ordain a bad outcome, how it is managed, does. Compared to CP cases, Red controls were delivered faster, had higher FRIs, and often had prompt management including IR maneuvers, which improved the FRI and lowered the risk of EODs even for cases with normal outcomes. With further study and validation, the quantitative FRI approach may replace the current, very subjective interpretation with a quantitative “lab test” approach.     

Brain maturation in the first 3 months of life,measured by electroencephalogram: A comparison between preterm and term-born infants

ObjectivePreterm infants are at risk for altered brain maturation resulting in neurodevelopmental impairments. Topographical analysis of high-density electroencephalogram during sleep matches underlying brain maturation. Using such an EEG mapping approach could identify preterm infants at risk early in life.Methods20 preterm (gestational age < 32 weeks) and 20 term-born infants (gestational age > 37 weeks) were recorded by 18-channel daytime sleep-EEG at term age (GA 40 weeks for preterm and 2–3 days after birth for term infants) and 3 months (corrected age for preterm infants).ResultsPreterm infant’s power spectrum at term age is immature, leveling off with term infants at 3 months of age. Topographical distribution of maximal power density however, reveals qualitative differences between the groups until 3 months of age. Preterm infants exhibit more temporal than central activation at term age and more occipital than central activation at 3 months of age. Moreover, being less mature at term age predicts being less mature at 3 months of age.ConclusionTopographical analysis of sleep EEG reveals changes in brain maturation between term and preterm infants early in life.SignificanceIn future, automated analysis tools using topographical power distribution could help identify preterm infants at risk early in life.