Does Recombinant Human Bone Morphogenic Protein 2 Affect Perioperative Blood Loss after Lumbar and Thoracic Spinal Fusion?

Study Design Retrospective cohort design. Purpose This study aimed to determine whether recombinant human bone morphogenic protein 2 (rhBMP-2) reduces total perioperative blood loss during lumbar and thoracic fusion. Overview of Literature Previous studies on rhBMP-2 versus iliac crest bone grafting in thoracic and lumbar fusions have yielded mixed results regarding reductions in blood loss and have largely neglected the postoperative period when analyzing total blood loss. Additionally, these studies have been limited by heterogeneity and sample size. Methods We analyzed the blood loss patterns of 617 consecutive adult patients undergoing lumbar and/or thoracic fusions requiring subfascial drain placement at a single institution from January 2009 to December 2016. Patients were divided into BMP and non-BMP cohorts, and a propensity score analysis was conducted to account for the differences between cohorts. Results At a per-level fused basis, the BMP group exhibited a significant reduction in the intraoperative (66.1 mL per-level fused basis; 95% confidence interval [CI], 127.9 to 4.25 mL; p=0.036) and total perioperative blood loss (100.7 mL per-level fused basis; 95% CI, 200.9 to 0.5 mL; p=0.049). However, no significant differences were observed in an analysis when not controlling for the number of levels or when examining the postoperative drain output. Conclusion RhBMP-2 appears to reduce both intraoperative and total blood loss during lumbar and thoracic fusions on a per-level fused basis. This total reduction in blood loss was achieved via intraoperative effects because RhBMP-2 had no significant effect on the postoperative drain output

An Ovariectomy-Induced Rabbit Osteoporotic Model: A New Perspective

Study DesignExperimental Animal Model.PurposeThe aim of our study was to validate a pure bilateral ovariectomy (OVX) female New Zealand white rabbit model of postmenopausal osteoporosis utilizing animal-sparing in vivo techniques for evaluating bone mineral density (BMD). We also sought to demonstrate that bilateral OVX in female New Zealand white rabbits can produce diminished BMD in the spinal column and simulate osteoporosis, without the need for adjuvant chemotherapeutic agents (i.e., no additional glucocorticosteroids or other drugs were used for stimulating accelerated BMD loss), which can be assessed by in vivo BMD testing.Overview of LiteratureMultiple animal models of postmenopausal osteoporosis have been described. Rat ovariectomy models have been successful, but are limited by rats' inability to achieve true skeletal maturity and a slight morphology that limits surgical instrumentation. Rabbit models have been described which do not have these limitations, but previous models have relied on adjunctive steroid therapy to achieve osteoporosis and have required animal sacrifice for bone mineral density assessment.MethodsThirty-six skeletally mature female rabbits underwent bilateral OVX. BMD was measured using dual-energy X-ray absorptiometry on the metaphysis of the proximal tibia and distal femur, at baseline and 17 weeks postoperatively.ResultsMean BMD values were significantly reduced by 21.9% (p<0.05) in the proximal tibia and 11.9% (p<0.001) in the distal femur at 17 weeks.ConclusionsThis study is the first to demonstrate a significant bone loss within four months of pure OVX in rabbits using animal-sparing validation techniques. We believe that this OVX model is safe, reproducible, and can be employed to longitudinally evaluate the effect of anti-osteoporosis therapeutics and surgical interventions

Osteoporosis-related Vertebral Fragility Fractures: A Review and Analysis of the American Orthopaedic Association\u27s Own the Bone Database

© 2020 Wolters Kluwer Health, Inc. All rights reserved. Study Design.Retrospective cohort study of the Own the Bone database which is a fracture liaison service designed to improve recognition and treatment of osteoporosis.Objective.To use the Own the Bone (OTB) database to 1) examine the specific demographics of patients presenting with a low-energy clinical vertebral fracture (VFX) and 2) compare demographic and fracture-specific risk factors between patients with clinical VFX versus patients with nonvertebral low-energy fracture (NVFX).Summary of Background Data.Large database studies have described risk factors for developing VFX. It is well described that a history of previous VFX portends an increased risk of future VFX. Few studies have reported cohorts from a fracture liaison service such as the OTB initiative.Methods.35,039 unique cases of fragility fracture occurred between 2009 and 2016 and were included in analysis. VFX accounted for 3395 (9.9%) of the presenting fractures at OTB enrollment. The demographics, lifestyle factors, medication use, and fracture-specific data for patients in the OTB registry with vertebral fractures were summarized and then statistically compared to those with nonvertebral fragility fractures.Results.The majority of VFX patients were Caucasian, postmenopausal women (74.4%). There was an increased likelihood of presenting with a vertebral fracture in patients who sustained a previous VFX after the age of 50, while patients who sustained a prior nonvertebral fracture (NVFX) were more likely to present with a subsequent NVFX. After controlling for patients with a history of fracture after the age of 50, VFX patients (vs. NVFX) were more likely to be age 70-79, class 1 obesity, with a history of taking anti-osteoporotic prescription medications.Conclusions.Multiple factors were associated with a significantly increased risk of VFX compared with NVFX. Understanding the risk factors unique to fragility VFX is a critical component for targeting at-risk patients and preventing future osteoporosis-related fractures and their consequences.Level of Evidence: 4