Fracture nonunion remains an unresolved complication after extremity fracture, with notable costs to patient quality of life and health systems. Nonunion is defined by the inability of fracture ends to unite without evidence of progressive healing over time. Approximately 2 to 10% of all fractures go onto nonunion, with increased rates observed in specific fracture locations and patient populations. Despite advances in fixation techniques and bone grafting, current treatments remain limited and frequently fail to restore durable bone healing. In this review, the current state of emerging biologic and bioengineering therapies for nonunion will be summarized, with a focus on how these advances may shift treatment from palliative reconstruction toward durable healing. Biological therapies such as growth factors, stem cells, and gene-modified constructs show promise but face challenges of short half-life, inconsistent efficacy, and safety concerns. Emerging approaches, including controlled-release scaffolds, immunomodulatory materials, stem cell-derived exosomes, and gene therapy platforms, offer opportunities to more precisely restore the osteogenic, angiogenic, and immunologic environment required for union.

Background Spine disorders are among the most common causes of disability, with utilization of spine procedures nearly doubling over the past 2 decades. As costs have continued to escalate, the Centers for Medicare & Medicaid Services have implemented bundled care initiatives and reimbursement reductions, leading to declining physician payment. This study provides a comprehensive summary of utilization and reimbursement for the most common spine procedures using a large national insurance database. Methods Patient data from 2010 to 2021 were accessed by querying the national insurance claims database using Current Procedural Terminology codes. After identifying the 10 most used spine procedures, the Physician Fee-Schedule Lookup Tool from the Centers for Medicare & Medicaid Services was queried to obtain Medicare physician reimbursement for the procedures (2012–2024). Dollar values were adjusted using the Consumer Price Index and are reported in 2024 US dollars. Yearly reimbursement was separated by procedure type and location. Utilization trends and demographic data were also obtained. Results From 2012 to 2021, 347,053 Medicare patients underwent 1 of the top 10 spine procedures, with fusion, laminectomy, and laminotomy being the most utilized. The average patient was 69 ± 8 years; 52.9% were women, with an average Elixhauser Comorbidity Index of 4.9 ± 3.7. Overall utilization increased by 19% (P = 0.04), with cervical and lumbar procedures rising by 30.61% (P = 0.01) and 19.97% (P = 0.04), respectively. Despite increased utilization, inflation-adjusted Medicare reimbursement significantly declined across all procedure types, with lumbar procedures experiencing the greatest reduction (−28.56%, P < 0.001). The largest annual decline occurred from 2021 to 2022 (−7.67% fusion and −7.52% decompression). Conclusion Despite the growing utilization of all included procedures, the present data have demonstrated a decrease in Medicare reimbursement across all subgroups. Clinical Relevance These reimbursement trends shape the field of spine surgery, impacting the sustainability of spine practices, affecting patient access to care, and influencing the adoption of new technologies. Level of Evidence 3.

Fracture nonunion or delayed union remains a significant clinical problem that burdens both the patient and the healthcare system. Defined as failure for bone to unite 9 months post injury or 3 months with no progression toward union, the pathology of nonunion may require multiple surgical interventions with associated morbidity. Increasing evidence has highlighted that nonunion is a multifaceted problem, not only a result of mechanical failure, but also a product of persistent dysregulation of the osteoimmune microenvironment manifested as impaired osteogenesis and bone healing. While current approaches focus on enhanced fixation and various bone grafting strategies, these treatments often fail to coordinate healing with osteoimmune regulation. This review summarizes the emerging biologic and bioengineering approaches that target osteoimmunology to enhance fracture repair. Scaffold systems, including metals, bioceramics, hydrogels, and micro/nanoparticle formulations, are being increasingly engineered to provide structural support while directing macrophage polarization and stimulating osteogenic signaling. We also review cell-based therapies and gene-modified constructs that are being developed to introduce osteoimmunology cues that halt chronic inflammation and promote an osteogenic microenvironment.

Osteoarthritis (OA) is a significant clinical problem that places a substantial burden on both patients and the healthcare system. Characterized by progressive cartilage degeneration, synovial inflammation, and subchondral bone remodeling, OA is a rapidly growing and increasingly studied disease affecting millions around the world. Growing evidence has expanded on the traditional view of OA as a mechanical “wear-and-tear” disease, highlighting that disease progression is driven not only by mechanical stress but also by chronic dysregulation of the osteoimmune environment. Activation of innate and adaptive immune pathways, macrophage M1 polarization, and dysregulated cytokine signaling all contribute to progressive joint degeneration. While current therapeutics often focus on managing symptoms or restoring joint mechanics, interventions often overlook the role of osteoimmunology in disease progression. This review summarizes the biological and bioengineering strategies emerging to address OA. These platforms include bioceramics, metal-based scaffolds, hydrogels, nanoparticles, and microsphere systems. Furthermore, small molecules, cell-based therapies, and gene-modified systems have also been shown to modulate the inflammatory microenvironment, enhance regulatory immune responses, and restore cartilage homeostasis. Together, these approaches represent the evolving research landscape, shifting away from just symptom alleviation and towards targeted disease-modifying therapies, including osteoimmunomodulation. However, significant barriers to clinical translation remain, such as limited large animal studies and species immune system differences, which need to be addressed for the development of clinically applicable interventions.

Purpose: To understand the development and trajectory of endoscopic spine surgery. Methods: The Web of Science Core Collection was searched for full-endoscopic and microendoscopic spine surgery articles published in 19 spine-related journals. Citation analysis identified top authors (first, last, and any position) and top cited articles. Study characteristics were reviewed, examining article type, level of evidence (LoE), topic, and country of origin. Results: 330 articles were identified, all published within the last 35 years. For the most frequently cited authors across all cohorts, a majority were affiliated with institutions in South Korea. Of the top 20 cited articles of all time, 55% were case series/case reports and 25% were randomized controlled trials, with 60% of studies having a LoE of IV. In the last decade (2014–2024), 30% of the top cited studies were case series/case reports, 25% were randomized controlled trials and 20% were systematic reviews/meta-analyses. Among these works, China (40%) and South Korea (25%) contributed the largest share of recent high-impact studies. Similarly, a large portion (35%) of the top articles of all time were associated with South Korean institutions. Conclusion: This bibliometric analysis highlighted the rapid advancement of the field of endoscopic spine surgery and highly cited authors who have been prominent within this field. This work particularly underscores a growing international focus on minimally invasive spinal techniques and the need for continued high-quality comparative studies.

Study Design: Database study. Objective: Given the high prevalence of degenerative lumbar pathologies, this study examines trends in computer-assisted navigation (CAN) utilization and complications in the top lumbar spine fusion procedures for degenerative conditions. Summary of Background Data: Intraoperative CAN has advanced minimally invasive techniques and anatomic characterization. However, studies on the use of CAN in lumbar spine surgery remain limited. Methods: Patient data (2010–2021) was extracted from a national insurance database using ICD-9, ICD-10, and CPT codes. The top 5 lumbar degeneration codes were identified, and associated lumbar fusion CPT codes were used to create a cohort. Patients were stratified by procedures with and without CAN. Temporal and multivariable analyses were performed on postoperative complications at 90 days. Results: A total of 771,874 lumbar fusion patients (2010–2021) were identified in the PearlDiver database, of whom 14,354 (1.86%) involved CAN. CAN utilization increased significantly from 0.62% (371 patients) in 2010 to 4.48% (2998 patients) in 2021, a 623.82% increase. The most rapid growth occurred from 2017–2021 (+189.73%). Multivariable analysis linked CAN to lower odds of revision surgery (aOR=0.79; 95% CI: 0.58–0.87) but higher odds of DVT (aOR=1.42; 95% CI: 1.28–1.76). Conclusion: Computer-assisted navigation (CAN) utilization in lumbar fusion has risen significantly, particularly in recent years. Outcome analysis suggests an association with reduced revision rates but increased DVT risk.