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STUDY DESIGN: Level 3 retrospective database study. OBJECTIVE: This study aims to compare work RVU (wRVU), practice expense RVU (peRVU), malpractice RVU (mpRVU), and inflation-adjusted facility price alongside MS-DRG relative weight length of stay (LOS) for cervical spine fusions between 2011 and 2023. SUMMARY OF BACKGROUND DATA: Both RVU and MS-DRG reimbursement have been studied in various surgical subspecialties; however, little investigation has centered on cervical spine fusions. To the best of our knowledge, this is the first study to investigate trends in RVU and MS-DRG reimbursement in cervical spine fusion throughout the COVID-19 pandemic. METHODS: Center for Medicaid and Medicare Services (CMS) physician fee schedule was queried between 2011 and 2023 for RVU and facility reimbursement using common single and multilevel anterior and posterior cervical fusion codes. RVU facility prices were inflation adjusted to 2023. MS-DRG reimbursement data from 2011 to 2022 were compiled for cervical spinal fusion procedures with major complication or comorbidity (MCC) 471, complication or comorbidity (CC) 472, and without CC/MCC 473. Compound annual growth rates (CAGRs), Mean Annual Change, and yearly percent changes were calculated. RESULTS: No changes in wRVU were seen for all cervical CPT codes; however, the CAGR of peRVU (-0.51%±0.60%) and mpRVU (0.69%±0.41%) demonstrated marginal fluctuations. Every CPT code displayed an inflation-adjusted facility price decrease (-2.18%±0.24%). When assessing MS-DRG, there were marginal changes in geometric mean LOS (0.17%±0.45%), arithmetic mean LOS (-0.15%±0.84%), and relative weight (1.09%±0.68%). Unlike RVU reimbursement, the yearly percent change differs between each MS-DRG code. CONCLUSIONS: Inflation-adjusted RVU reimbursement facility prices demonstrated a consistent decrease, while DRG code reimbursement stayed relatively consistent over the study period. This data may help surgeons and hospitals become cognizant of temporal variations in reimbursement patterns as it may affect their personal practice. LEVEL OF EVIDENCE: Level III retrospective study.
RESUMEN
Polyelectrolyte complex particles assembled from plasmid DNA (pDNA) and poly(ethylenimine) (PEI) have been widely used to produce lentiviral vectors (LVVs) for gene therapy. The current batch-mode preparation for pDNA/PEI particles presents limited reproducibility in large-scale LVV manufacturing processes, leading to challenges in tightly controlling particle stability, transfection outcomes, and LVV production yield. Here we identified the size of pDNA/PEI particles as a key determinant for a high transfection efficiency with an optimal size of 400-500 nm, due to a cellular-uptake-related mechanism. We developed a kinetics-based approach to assemble size-controlled and shelf-stable particles using preassembled nanoparticles as building blocks and demonstrated production scalability on a scale of at least 100 mL. The preservation of colloidal stability and transfection efficiency was benchmarked against particles generated using an industry standard protocol. This particle manufacturing method effectively streamlines the viral manufacturing process and improves the production quality and consistency.