Weighing the Impact: The Influence of Body Mass Index on Facility Costs in Total Joint Arthroplasty.

BACKGROUND: Using time-driven activity-based costing (TDABC), a novel cost calculation method that more accurately reflects true resource utilization in health care, we sought to compare the total facility costs across different body mass index (BMI) groups following total joint arthroplasty (TJA). METHODS: The study consisted of 13,806 TJAs (7,340 total knee arthroplasties [TKAs] and 6,466 total hip arthroplasties [THAs]) performed between 2019 and 2023. The TDABC data from an analytics platform was employed to depict total facility costs, comprising personnel and supply costs. For the analysis, patients were stratified into four BMI categories: <30, 30 to <35, 35 to <40, and ≥40. Multivariable regression was used to determine the independent effect of BMI on facility costs. RESULTS: When indexed to patients who had BMI <30, elevated BMI categories (30 to <35, 35 to <40, and ≥40) were associated with higher total personnel costs (TKA 1.03x versus 1.07x versus 1.13x, P < .001; THA 1.00x versus 1.08x versus 1.08x, P < .001), and total supply costs (TKA 1.01x versus 1.04x versus 1.04x, P < .001; THA 1.01x versus 1.02x versus 1.03x, P = .007). Total facility costs in TJAs were significantly greater in higher BMI categories (TKA 1.02x versus 1.05x versus 1.08x, P < .001; THA 1.01x versus 1.05x versus 1.05x, P < .001). Notably, when incorporating adjustments for demographics and comorbidities, BMI values of 35, 40, and 45 relative to BMI of 25, exhibit a significant association with a 2, 3, and 5% increase in total facility cost for TKAs and a 3, 5, and 7% increase for THAs. CONCLUSIONS: Using TDABC methodology, this study found that overall facility costs of TJAs increase with BMI. The present study provides patient-level cost insights, indicating the potential need for reassessment of physician compensation models in this population. Further studies may facilitate the development of risk-adjusted procedural codes and compensation models for public and private payors. LEVEL OF EVIDENCE: Level IV, economic and decision analyses.

Odontoid fractures above C2 to pelvis posterior instrumented fusions: a single center's 11-year experience.

PURPOSE: To define the prevalence, characteristics, and treatment approach for proximal junction failure secondary to odontoid fractures in patients with prior C2-pelvis posterior instrumented fusions (PSF). METHODS: A single institution's database was queried for multi-level fusions (6+ levels), including a cervical component. Posterior instrumentation from C2-pelvis and minimum 6-month follow-up was inclusion criteria. Patients who sustained dens fractures were identified; each fracture was subdivided based on Anderson & D'Alonzo and Grauer's classifications. Comparisons between the groups were performed using Chi-square and T tests. RESULTS: 80 patients (71.3% female; average age 68.1 ± 8.1 years; 45.0% osteoporosis) were included. Average follow-up was 59.8 ± 42.7 months. Six patients (7.5%) suffered an odontoid fracture post-operatively. Cause of fracture in all patients was a mechanical fall. Average time to fracture was 23 ± 23.1 months. Average follow-up after initiation of fracture management was 5.84 ± 4 years (minimum 1 year). Three patients sustained type IIA fractures one of which had a concomitant unilateral C2 pars fracture. Three patients sustained comminuted type III fractures with concomitant unilateral C2 pars fractures. Initial treatment included operative care in 2 patients, and an attempt at non-operative care in 4. Non-operative care failed in 75% of patients who ultimately required revision with proximal extension. All patients with a concomitant pars fracture had failure of non-operative care. Patients with an intact pars were more stable, but 50% required revision for pain. CONCLUSIONS: In this 11-year experience at a single institution, the prevalence of odontoid fractures above a C2-pelvis PSF was 7.5%. Fracture morphology varied, but 50% were complex, comminuted C2 body fractures with concomitant pars fractures. While nonoperative management may be suitable for type II fractures with simple patterns, more complex and unstable fractures likely benefit from upfront surgical intervention to prevent fracture displacement and neural compression. As all fractures occurred secondary to a mechanical fall, inpatient and community measures aimed to minimize risk and prevent mechanical falls would be beneficial in this high-risk group.

YAP localization mediates mechanical adaptation of human cancer cells during extravasation in vivo.

Biophysical profiling of primary tumors has revealed that individual tumor cells fall along a highly heterogeneous continuum of mechanical phenotypes. One idea is that a subset of tumor cells is "softer" to facilitate detachment and escape from the primary site, a step required to initiate metastasis. However, it has also been postulated that cells must be able to deform and generate sufficient force to exit into distant sites. Here, we aimed to dissect the mechanical changes that occur during extravasation and organ colonization. Using multiplexed methods of intravital microscopy and optical tweezer based active microrheology, we obtained longitudinal images and mechanical profiles of cells during organ colonization in vivo. We determined that cells were softer, more liquid like upon exit of the vasculature but stiffened and became more solid like once in the new organ microenvironment. We also determined that a YAP mediated mechanogenotype influenced the global dissemination in our in vivo and in vitro models and that reducing mechanical heterogeneity could reduce extravasation. Moreover, our high throughput analysis of mechanical phenotypes of patient samples revealed that this mechanics was in part regulated by the external hydrodynamic forces that the cancer cells experienced within capillary mimetics. Our findings indicate that disseminated cancer cells can keep mutating with a continuum landscape of mechano-phenotypes, governed by the YAP-mediated mechanosensing of hydrodynamic flow.

The Human Microbiome and Its Role in Musculoskeletal Disorders.

Musculoskeletal diseases (MSDs) are characterized as injuries and illnesses that affect the musculoskeletal system. MSDs affect every population worldwide and are associated with substantial global burden. Variations in the makeup of the gut microbiota may be related to chronic MSDs. There is growing interest in exploring potential connections between chronic MSDs and variations in the composition of gut microbiota. The human microbiota is a complex community consisting of viruses, archaea, bacteria, and eukaryotes, both inside and outside of the human body. These microorganisms play crucial roles in influencing human physiology, impacting metabolic and immunological systems in health and disease. Different body areas host specific types of microorganisms, with facultative anaerobes dominating the gastrointestinal tract (able to thrive with or without oxygen), while strict aerobes prevail in the nasal cavity, respiratory tract, and skin surfaces (requiring oxygen for development). Together with the immune system, these bacteria have coevolved throughout time, forming complex biological relationships. Changes in the microbial ecology of the gut may have a big impact on health and can help illnesses develop. These changes are frequently impacted by lifestyle choices and underlying medical disorders. The potential for safety, expenses, and efficacy of microbiota-based medicines, even with occasional delivery, has attracted interest. They are, therefore, a desirable candidate for treating MSDs that are chronic and that may have variable progression patterns. As such, the following is a narrative review to address the role of the human microbiome as it relates to MSDs.

Obesity in children with low back pain: implications with imaging phenotypes and opioid use.

BACKGROUND CONTEXT: Low back pain (LBP) is common in children and adolescents, carrying substantial risk for recurrence and continuation into adulthood. Studies have linked obesity to the development of pediatric LBP; however, its association with lumbar spine degeneration, alignment parameters, and opioid use remains debated. PURPOSE: Considering the increasing prevalence of pediatric obesity and LBP and the inherent issues with opioid use, this study aimed to assess the association of obesity with lumbar spine degeneration, spinopelvic alignment, and opioid therapy among pediatric patients. STUDY DESIGN/SETTING: A retrospective study of pediatric patients presenting to a single institute with LBP and no history of spine deformity, tumor, or infection was performed. PATIENT SAMPLE: A totasl of 194 patients (mean age: 16.7±2.3 years, 45.3% male) were included, of which 30 (15.5%) were obese. OUTCOME MEASURES: Prevalence of imaging phenotypes and opioid use among obese to nonobese pediatric LBP patients. Magnetic resonance and plain radiographic imaging were evaluated for degenerative phenotypes (disc bulging, disc herniation, disc degeneration [DD], high-intensity zones [HIZ], disc narrowing, Schmorl's nodes, endplate phenotypes, Modic changes, spondylolisthesis, and osteophytes). Lumbopelvic parameters including lumbar lordosis, pelvic tilt, sacral slope, pelvic incidence and pelvic incidence-lumbar lordosis (PI-LL) mismatch were also examined. METHODS: Demographic and clinical information was recorded, including use of opioids. The associations between obesity and lumbar phenotypes or opiod use were assessed by multiple regression models. RESULTS: Based on multivariate analysis, obesity was significantly associated with the presence of HIZ (adjusted OR: 5.36, 95% CI: 1.30 to 22.09). Further analysis demonstrated obesity (adjusted OR: 3.92, 95% CI: 1.49 to 10.34) and disc herniation (OR: 4.10, 95% CI: 1.50 to 11.26) were associated with opioid use, independent of duration of symptoms, other potential demographic determinants, and spinopelvic alignment. CONCLUSIONS: In pediatric patients, obesity was found to be significantly associated with HIZs of the lumbar spine, while disc herniation and obesity were associated with opioid use. Spinopelvic alignment parameters did not mitigate any outcome. This study underscores that pediatric obesity increases the risk of developing specific degenerative spine changes and pain severity that may necessitate opioid use, emphasizing the importance of maintaining healthy body weight in promoting lumbar spine health in the young.

Smart polymeric nanofibers for topical delivery of levothyroxine.

Topical administration of levothyroxine (T4) helps to reduces deposits of adipose tissue on skin. The question is whether topical application of T4 could lead to systemic effects. In the present study a series of nanofibrous membranes were electrospun into blends of poly vinyl alcohol (PVA) and poly-N-isopropylacrylamide (PNIPAM) to develop a sustained topical delivery of T4. The polymeric nanofiber mats were characterized by field emission scanning electron microscopy (FESEM) and fourier transform infrared (FTIR) spectroscopy. In vitro permeation of the drug from the polymeric nanofibers was studied using excised human skin and the permeation mechanism investigated using confocal microscopy. It was observed that polymeric nanofibers were able to sustain the penetration of T4 to the skin and help maintain the effective drug concentration in the skin layers for longer period of time. These formulations may have potential uses in topical skin products and can help to increase the accumulation of the active compound on the skin surface thus minimize the adverse side effects which may be caused by systemic absorption. This may result in great improvement in consumer compliance, avoid frequent dosing and enhance the therapeutic effectiveness.

Physicochemical effects of terpenes on organogel for transdermal drug delivery.

It is accepted that terpenes are effective penetration enhancers to promote the passage of drugs or chemicals through the human skin barrier. However the physical and chemical changes of a pharmaceutical vehicle induced by the incorporation of terpenes have not been explored. Thus, this study examines the effects of three terpenes (linalool, cineole, limonene) on the rheology and chemical stability of an organogel composed of dibutyllauroylglutamide (GP1) and propylene glycol (PG). At a given GP1 concentration, oxygen-containing linalool and cineole decreased gel moduli (elastic and viscous) and brittleness, and the reverse was obtained for hydrocarbon limonene. Probably, linalool and cineole interfered with hydrogen bonding between GP1 molecules while limonene could have initiated a phase separation-mediated gelation, changing the gel morphology. Microcalorimetry detected minute heat endotherms for gels (with and without terpenes) subjected to accelerated heat testing. These heat changes could arise from a small degree of structural disruption of the gel network. Heat endotherms normalized with respect to GP1 content were used to assess gel chemical stability. Although the terpenes altered rheology, they did not significantly affect the chemical stability of the gels. This is the first in the literature that reports the effect of penetration enhancers, such as terpenes, on the physical, rheological and chemical characteristics of a model pharmaceutical formulation for topical and transdermal drug delivery.

Limonene GP1/PG organogel as a vehicle in transdermal delivery of haloperidol.

Penetration enhancers are a classical means for improving transdermal drug delivery (TDD). Enhancers permeate into the skin and reversibly decrease the barrier resistance. Basically, our aim is to formulate a transdermal gel containing an appropriate enhancer for a controlled drug release. Terpenes, namely limonene, linalool and cineole, in propylene glycol (PG) were first investigated in vitro for their capacity to enhance the percutaneous release of an anti-psychotic drug, haloperidol (HP). Relative to oxygenated linalool and cineole, hydrocarbon limonene was more effective as a skin enhancer; it increased human skin permeability and decreased lag time. Limonene was thus incorporated in an organogel comprised of gelator GP1 and PG. This skin-friendly gel in a transdermal patch could act as a long-acting formulation that delivers HP at a sustained percutaneous rate. The microscopic framework of the organogel is a branched network of interlocking fibres. Varying the gelator content modulates the fibre density and gel stiffness, and presents different degrees of resistance to drug diffusion on the vehicle side. Rheological and permeation studies demonstrated that an increase in gelator concentration increased gel moduli and decreased drug flux simultaneously. The rheology of the gel matrix influenced drug release rate in a manner described by several experimentally-derived correlations.