Estimated Cost of Transcarotid Arterial Revascularization Compared With Carotid Endarterectomy and Transfemoral Carotid Stenting.

Objectives Transcarotid arterial revascularization (TCAR) is associated with a lower risk of stroke or death than transfemoral carotid artery stenting (TF-CAS). TCAR infers a lower risk of cranial nerve injury and a similar risk of myocardial infarction (MI) than carotid endarterectomy (CEA). There have been no comparative studies on the cost of TCAR, TF-CAS, and CEA, which may have important implications for institutional support for the new modality to address carotid artery stenosis. Our aim was to compare the estimated cost profiles of TCAR, TF-CAS, and CEA. Methods A review was performed on Medicare patients who underwent TCAR, TF-CAS, or CEA between January 1, 2020, and December 31, 2020. Demographics, comorbidities, operative details, and postoperative complications were reviewed. Acute stroke presentations and elective procedures were included. Cost data were obtained from the hospital's finance department. Quantitative variables were compared using analysis of variance, and categorical variables were compared using the chi-square analysis. Results In total, 21 TCAR, 97 TF-CAS, and 26 CEA patients were initially identified. After removing the non-Medicare patients, 17 TCAR, 57 TF-CAS, and 13 CEA patients were included in the analysis. In-hospital stroke, MI, and mortality included three deaths in TF-CAS patients. At 30 days, the stroke rates for TCAR, TF-CAS, and CEA groups were 0%, 1.8%, and 0%, respectively. The payments for TCAR, TF-CAS, and CEA were $15,400 ± 2,100, $23,400 ± 11,800 and $14,300 ± 5,700 (p=0.001), respectively. The estimated costs for TCAR, TF-CAS, and CEA were $10,500 ± 3,300, $13,800 ± 14,300, and $12,400 ± 6,000 (p=0.575), respectively. The profit margins for TCAR, TF-CAS, and CEA were $5,100 ± 3,100, $9,600 ± 12,100, and $1,900 ± 6,400 (p=0.032), respectively. There was no significant difference in American Society of Anesthesiologists (ASA) scores (p=0.635) or age (p=0.485) among the three groups. The length of hospital stay was not significantly different (p=0.107). The TF-CAS maintained the highest profit margin (p<0.001) when matched for the same diagnosis-related code (without complications or comorbidities). Urgency classification within the TF-CAS group included 45 elective, four urgent, and eight emergent cases. The profit margin was significantly higher for the elective group than for the emergent group (p=0.002) but not different for elective versus urgent (p=0.503) or urgent versus emergent (p=0.102). All patients who underwent TCAR and CEA were elective. Conclusion The hospital reimbursement and profit margins are higher for TF-CAS than for TCAR. With the increasing data now demonstrating similar outcomes with TF-CAS and CEA, further research is required to examine the long-term cost-effectiveness of TCAR and how this will compare to TF-CAS.

Periprosthetic joint infection.

Periprosthetic joint infections are a devastating complication after arthroplasty and are associated with substantial patient morbidity. More than 25% of revisions are attributed to these infections, which are expected to increase. The increased prevalence of obesity, diabetes, and other comorbidities are some of the reasons for this increase. Recognition of the challenge of surgical site infections in general, and periprosthetic joint infections particularly, has prompted implementation of enhanced prevention measures preoperatively (glycaemic control, skin decontamination, decolonisation, etc), intraoperatively (ultraclean operative environment, blood conservation, etc), and postoperatively (refined anticoagulation, improved wound dressings, etc). Additionally, indications for surgical management have been refined. In this Review, we assess risk factors, preventive measures, diagnoses, clinical features, and treatment options for prosthetic joint infection. An international consensus meeting about such infections identified the best practices and further research needs. Orthopaedics could benefit from enhanced preventive, diagnostic, and treatment methods.

Temporary polysaccharide dermal fillers: a model for persistence based on physical properties.

BACKGROUND: The physical and chemical properties that control the clinical persistence of temporary dermal fillers are not well understood. Discovering the relationship between the clinical performance and physical properties of temporary fillers may stimulate the design of future, high-performance fillers. OBJECTIVE: Described here is the rheology of polysaccharide dermal fillers composed of cross-linked hyaluronic acid (XLHA) or un-cross-linked sodium carboxymethylcellulose (CMC) and polyethylene oxide (PEO). Using measured rheology data and published clinical study data, we have developed a predictive model for the persistence of polysaccharide-containing dermal fillers. METHODS AND MATERIALS: The XLHA dermal fillers were obtained from commercial sources. The CMC/PEO dermal filler formulation was prepared in house. The rheologic properties of the polysaccharide fillers were measured and related to comparative clinical persistence data available from controlled clinical studies. RESULTS: The clinical persistence of the polysaccharide dermal fillers correlates linearly with the concentration of polymer in the formulation divided by the tan delta (G''/G'). SUMMARY: The work described here has shown that a model relating the concentration of the polysaccharide and the tan delta of the formulation can predict the comparative clinical persistence of XLHA and CMC/PEO dermal fillers.

Crosslinked hyaluronic acid dermal fillers: a comparison of rheological properties.

Temporary dermal fillers composed of crosslinked hyaluronic acid (XLHA) are space filling gels that are readily available in the United States and Europe. Several families of dermal fillers based on XLHA are now available and here we compare the physical and rheological properties of these fillers to the clinical effectiveness. The XLHA fillers are prepared with different crosslinkers, using HA isolated from different sources, have different particle sizes, and differ substantially in rheological properties. For these fillers, the magnitude of the complex viscosity, |eta*|, varies by a factor of 20, the magnitude of the complex rigidity modulus, |G*|, and the magnitude of the complex compliance, |J*| vary by a factor of 10, the percent elasticity varies from 58% to 89.9%, and the tan delta varies from 0.11 to 0.70. The available clinical data cannot be correlated with either the oscillatory dynamic or steady flow rotational rheological properties of the various fillers. However, the clinical data appear to correlate strongly with the total concentration of XLHA in the products and to a lesser extent with percent elasticity. Hence, our data suggest the following correlation: dermal filler persistence = [polymer] x [% elasticity] and the clinical persistence of a dermal filler composed of XLHA is dominated by the mass and elasticity of the material implanted. This work predicts that the development of future XLHA dermal filler formulations should focus on increasing the polymer concentration and elasticity to improve the clinical persistence.

Novel synthetic dermal fillers based on sodium carboxymethylcellulose: comparison with crosslinked hyaluronic acid-based dermal fillers.

BACKGROUND: The persistence of dermal fillers containing crosslinked hyaluronic acid (XLHA) correlates linearly to the concentration of polymer in solution. For dermal fillers composed of XLHA, a polymer concentration above approximately 25 mg/mL is not practical because it cannot be easily injected through a small-bore needle. OBJECTIVE: Formulating dermal fillers from mixtures of carboxymethylcellulose (CMC) and polyethylene oxide (PEO) has several advantages over XLHA. We hypothesize that increasing the concentration of CMC/PEO will increase the persistence in the dermis. These polymers of CMC and PEO can be formulated at higher concentrations than XLHA to produce smooth, particulate-free gels resulting in easier, more controllable injection. Second, these gels are not required to be covalently crosslinked; CMC/PEO forms a stable gel-like structure in solution without crosslinking. MATERIALS AND METHODS: Here we have prepared dermal fillers from CMC/PEO polymer blends at concentrations of 20 mg/mL (dermal filler 1), 29 mg/mL (dermal filler 2), 37 mg/mL (dermal filler 3), and 45 mg/mL (dermal filler 4) and measured their rheologic properties compared to commercial XLHA dermal fillers. RESULTS AND CONCLUSIONS: The data here demonstrate that it is possible to duplicate the rheologic properties of commercial XLHA fillers using CMC/PEO at different polymer concentrations to formulate improved dermal fillers. All of the dermal filler formulations prepared can be easily injected through 30-gauge needles.

Rheological and cohesive properties of hyaluronic acid.

Hyaluronic acid (HA) is a naturally occurring polysaccharide with unique biomedical applications. We have studied the cohesive and rheological properties of HA of three molecular weights (0.35 x 10(6) -1.80 x 10(6) Da) and found that the cohesive nature of HA was highly dependent on molecular weight and solution concentration. To a first approximation, the cohesive nature of HA in solution correlates with concentration, independent of molecular weight. Several rheological parameters correlated with molecular weight: zero shear viscosity, complex viscosity, and the complex viscosity at the crossover point. The cohesive properties of the HA solutions, measured by dynamic aspiration (Poyer et al, J Cataract Refract Surg 1998;24:1130-1135), were found to decrease as the zero shear viscosity increases. The cohesive properties of HA polymer in solution were found to correlate with the high frequency complex viscosity and high frequency loss modulus independent of molecular weight.

Reduction of epidural fibrosis in lumbar surgery with Oxiplex adhesion barriers of carboxymethylcellulose and polyethylene oxide.

BACKGROUND CONTEXT: Postsurgical epidural adhesions and fibrosis after surgery for lumbar disc herniation are a consequence of normal wound healing. The presence of fibrosis renders reoperations risky, and in some patients fibrosis may lead to nerve root tethering. PURPOSE: One approach to minimizing the risk of developing epidural adhesions is to provide a barrier between the dural membrane and the healing connective tissues. The purpose of these studies was to evaluate such a barrier device. STUDY DESIGN/SETTING: In vivo investigation in an animal model at a university laboratory. PATIENT SAMPLE: Rabbit. OUTCOME MEASURES: Gross and histomorphic evaluation. METHODS: Barriers comprised of carboxymethylcellulose (CMC) and polyethylene oxide (PEO) (Oxiplex; FzioMed, Inc., San Luis Obispo, CA) were studied as devices to reduce epidural adhesion formation in rabbit laminotomy and laminectomy models. The barriers tested were either a gel alone (gel) or a gel covered with a film (gel/film combination). Two laminotomy or laminectomy sites (depending on the surgical method) were created in each rabbit at L4 and L6. One site was treated with a CMC/PEO gel, or CMC/PEO gel/film combination, and the other site served as a surgical control. Two surgical models that differed in the extent of adhesion formation at untreated injury sites and the method of injury generation were used. RESULTS: Model A, which did not incorporate dural abrasion, resulted in up to 40% adhesion-free laminectomy sites in controls. Model B, which did incorporate abrasion of the dural membrane, resulted in less than 10% adhesion-free laminotomy sites in controls. Compositions of CMC/PEO gels (2.5% to 10% PEO) and films (22.5% PEO) were tested in both models. Efficacy parameters included measuring the number of sites free of epidural fibrosis and reduction in the severity of fibrosis (adhesions). Both gels and gel/film combinations consistently reduced the frequency and the extent of epidural fibrosis in both models. Gels of CMC/PEO containing a higher content of PEO (10%) and a higher molecular weight of PEO (4.4 mD) were most effective in Model B and resulted in up to 84% laminotomy sites with minimal or no epidural fibrosis, whereas controls exhibited over 90% of the sites with epidural fibrosis. Histological evaluation of the surgical sites indicated that the reduction of epidural fibrosis was accompanied by normal bone healing. In addition, these experiments demonstrated that the gel/film combination provided no additional benefit to that obtained by the gel alone. CONCLUSIONS: Gels of CMC/PEO reduced epidural fibrosis and did not impair normal heal ing.

Adhesion barriers of carboxymethylcellulose and polyethylene oxide composite gels.

Composite gels and films of CMC and PEO have been used to separate healing tissues and have been demonstrated to reduce postsurgical adhesions in animal models of adhesion formation. Gels of CMC/PEO were studied here to elucidate the mechanism by which the combination of PEO with CMC is effective in reducing adhesions between tissues. CMC and PEO were demonstrated to undergo micro phase separation to form a two-phase system. Protein partitioning was measured in this system for albumin, fibrinogen, and gamma globulin. All of these proteins were found to partition preferentially into the CMC phase. When gels of CMC and PEO were examined for tissue adherence, the addition of PEO reduced the adherence of CMC to tissues. To further investigate the effects of PEO on tissue adherence of the gel, the extent of thrombus formation of citrated blood initiated by calcium chloride in CMC/PEO gels was measured in vitro. The extent of thrombus formation by CMC was reduced proportionally to the content of PEO in gels of CMC/PEO. A model was developed to explain how CMC and PEO contribute to the effectiveness of CMC/PEO gels that form a barrier between healing tissues to reduce postsurgical adhesions. In an open system PEO is released from the gel faster than CMC is dissolved, resulting in a shell structure with CMC coated by PEO. The PEO-rich outer layer functions to inhibit protein deposition and thrombus formation. The CMC-rich layer functions to anchor the gel to the tissue surface.