Intracorporeal bone grafting in stent-armed kyphoplasty for acute traumatic vertebral body burst fractures: histological evidence of allogeneic bone graft vascularization and incorporation
Year: 2026
Type: article
Study design: Clinical Trial
Abstract: Background: The optimal management of thoracolumbar burst fractures remains controversial. Increasing evidence suggests that anatomical and biological restoration of the vertebral body is important in young and middle-aged patients, who are expected to experience cumulative spinal loading throughout life, as it may restore structural integrity, load-bearing capacity, and spinal function while minimizing post-traumatic degenerative changes. The objective of this study was to characterize the histological healing response at the cellular level following a novel surgical technique involving intracorporeal bone allografting for vertebral burst fractures and to determine whether this approach can achieve biological reconstruction of the vertebral body as a living osseous structure.Methods: A prospective study included 32 patients with acute traumatic thoracolumbar complete burst fractures treated using a novel vertebral body reconstruction technique combining pedicle fixation, stent-armed kyphoplasty, and intracorporeal allogeneic bone grafting. Between 1 and 2 years postoperatively, intra-stent bone biopsy was offered to assess allograft incorporation and healing prior to posterior instrumentation removal; biopsies were obtained from the left-sided stent. Histological analysis was performed using an automated algorithm trained to identify nuclei associated with bone tissue and bone marrow (Bm), as well as inflammatory and fibrous tissues. Quantitative assessment was based on nuclear density and the relative proportion of nuclei. Specimens were also evaluated for the presence of perfused vessels and evidence of bone necrosis or graft rejection.Results: From a total of 32 patients, 9 opted not to undergo pedicle instrumentation removal and therefore did not undergo biopsy. Bone core biopsy specimens were obtained from within the stents in 22 of the 23 biopsied patients, with successful histological demonstration of viable, incorporated bone allograft in all 22 cases. Allograft incorporation and revascularization were characterized by the presence of trabecular bone (Tb) containing osteocyte-filled lacunae and cellular Bm, with identifiable sinusoids and capillaries containing erythrocytes. No histological evidence of bone necrosis or graft rejection was observed. The majority of detected cell nuclei were associated with bone and Bm tissues, whereas fibrous and inflammatory tissues were present only focally and in limited amounts. For bone tissue, the mean nuclear density was 359.07±250.07 nuclei/mm2, with a mean nuclear proportion of 13.17%±10.64%. The mean nuclear density of Bm was 5,670.04±4,204.17 nuclei/mm2, with a mean nuclear proportion of 79.82%±16.17%.Conclusions: This study provides the first human histological evidence of revascularization, cellular repopulation, and biological incorporation of intracorporeal allograft placed within expandable stents following stent-armed kyphoplasty for acute traumatic vertebral burst fractures. These findings provide preliminary evidence supporting the biological reconstructive potential of this novel minimally invasive surgical approach and its underlying aim of achieving an osseous reconstructed vertebral body, while providing a foundation for future comparative studies and further clinical investigation.
Source: Journal of Spine Surgery
Institutions: Unidade Local de Saúde de Coimbra, University of Coimbra
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7224000101