Quantitative Ultrasound of the Mandible as a Novel Screening Approach for Osteoporosis

This study used an axial transmission quantitative ultrasound (QUS) device to assess mandibular bone strength. The aim of the study was first to establish the precision and repeatability of the axial transmission QUS measurement for a range of mandibular anatomic sites, and second to investigate the ability of the modality to differentiate between osteoporotic subjects and a control group. Three groups of adult Caucasian women were recruited: (1) healthy premenopausal women (n?=?26), (2) healthy postmenopausal women (n?=?48), and (3) women with osteoporosis (n?=?53). Subjects were excluded from groups 1 and 2 if they had any pre-existing bone conditions. Speed of sound (SOS) measurements were taken from the mandible using an OmniSense multisite QUS device. Group 3 had dual-energy X-ray absorptiometry scans of the lumbar spine and femur. The most suitable site on the mandible was determined by repeat SOS measurements in 10 healthy premenopausal subjects, at 5 different sites. The parasymphysis site had the lowest root mean squared coefficient of variation at 0.74%, and was chosen as the most suitable site for mandibular SOS measurements. Group 1 and group 2 had significantly higher mean SOS measurements than the osteoporotic subjects (group 3), with means of 3683?m/s (210), 3514?m/s (221), and 3312?m/s (264), respectively. A 1-way analysis of variance confirmed a statistically significant difference between mean SOS measurements from the 3 groups (p?<?0.0001). Axial transmission QUS of the mandible can differentiate between subjects with osteoporosis and a healthy control group, and shows potential for use as a screening tool for osteoporosis.     

Contingent Valuation Studies in Orthopaedic Surgery: A Health Economic Review

Background

A greater emphasis on providing high-value orthopaedic interventions has resulted in increased health economic reporting. The contingent-valuation method (CVM) is used to determine consumer valuation of the benefits provided by healthcare interventions. CVM is an important value-based health economic tool that is underutilized in orthopaedic surgery.

Questions/Purposes

The purpose of this study was to (1) identify previously published CVM studies in the orthopaedic literature, (2) assess the methodologies used for CVM research, and (3) understand how CVM has been used in the orthopaedic cost–benefit analysis framework.

Methods

A systematic review of the literature using the MEDLINE database was performed to compile CVM studies. Search terms incorporated the phrase willingness to pay (WTP) or willingness to accept (WTA) in combination with orthopaedic clinical key terms. Study methodology was appraised using previously defined empirical and conceptual criteria for CVM studies.

Results

Of the 160 studies retrieved, 22 (13.8%) met our inclusion criteria. The economics of joint arthroplasty (n?=?6, 27.3%) and non-operative osteoarthritis care (n?=?4, 18.2%) were the most common topics. Most studies used CVM for pricing and/or demand forecasting (n?=?16, 72.7%); very few studies used CVM for program evaluation (n?=?6). WTP was used in all included studies, and one study used both WTP and WTA. Otherwise, there was little consistency among included studies in terms of CVM methodology. Open-ended questioning was used by only ten studies (45.5%), a significant number of studies did not perform a sensitivity analysis (n?=?9, 40.9%), and none of the studies accounted for the risk preference of subjects. Only two of the included studies applied CVM within a cost–benefit analysis framework.

Conclusion

CVM is not commonly reported in orthopaedic surgery and is seldom used in the context of cost–benefit analysis. There is wide variability in the methods used to perform CVM. We propose that CVM is an appropriate and underappreciated method for understanding the value of orthopaedic interventions. Increased attention should be paid to consumer valuations for orthopaedic interventions.

     

Mastopexy for breast ptosis: Utility outcomes of population preferences

BACKGROUND:

Breast ptosis can occur with aging, and after weight loss and breastfeeding. Mastopexy is a procedure used to modify the size, contour and elevation of sagging breasts without changing breast volume. To gain more knowledge on the health burden of living with breast ptosis requiring mastectomy, validated measures can be used to compare it with other health states.

OBJECTIVE:

To quantify the health state utility assessment of individuals living with breast ptosis who could benefit from a mastopexy procedure; and to determine whether utility scores vary according to participant demographics.

METHODS:

Utility assessments using a visual analogue scale (VAS), time trade-off (TTO) and standard gamble (SG) methods were used to obtain utility scores for breast ptosis, monocular blindness and binocular blindness from a sample of the general population and medical students. Linear regression and the Student’s t test were used for statistical analysis; P<0.05 was considered to be statistically significant.

RESULTS:

Mean (± SD) measures for breast ptosis in the 107 volunteers (VAS: 0.80±0.14; TTO: 0.87±0.18; SG: 0.90±0.14) were significantly different (P<0.0001) from the corresponding measures for monocular blindness and binocular blindness. When compared with a sample of the general population, having a medical education demonstrated a statistically significant difference in being less likely to trade years of life and less likely to gamble risk of a procedure such as a mastopexy. Race and sex were not statistically significant independent predictors of risk acceptance.

DISCUSSION:

For the first time, the burden of living with breast ptosis requiring surgical intervention was determined using validated metrics (ie, VAS, TTO and SG). The health burden of living with breast ptosis was found to be comparable with that of breast hypertrophy, unilateral mastectomy, bilateral mastectomy, and cleft lip and palate. Furthermore, breast ptosis was considered to be closer to ‘perfect health’ than monocular blindness, binocular blindness, facial disfigurement requiring face transplantation surgery, unilateral facial paralysis and severe lower extremity lymphedema.

CONCLUSIONS:

Quantifying the health burden of living with breast ptosis requiring mastopexy indicated that is comparable with other breast-related conditions (breast hypertrophy and bilateral mastectomy). Numerical values have been assigned to this health state (VAS: 0.80±0.14; TTO: 0.87±0.18; and SG: 0.90±0.14), which can be used to form comparisons with the health burden of living with other disease states.     

Mathematical modeling of extracorporeal CO<Subscript>2</Subscript> removal therapy

The extracorporeal CO₂ removal device (ECCO₂RD) is used in clinics to treat patients suffering from respiratory failures like acute respiratory distress syndrome (ARDS) or chronic obstructive pulmonary disease (COPD). The aim of this device is to decarboxylate blood externally with low blood flow. A mathematical model is proposed to describe protective ventilation, ARDS, and an extracorporeal CO₂ removal therapy (ECCO₂RT). The simulations are compared with experimental data carried out on ten pigs. The results show a good agreement between the mathematical simulations and the experimental data, which provides a nice validation of the model. This model is thus able to predict the decrease of PCO₂ during ECCO₂RT for different blood flows across the extracorporeal lung support.