The vacuum phenomenon in the lumbar spine is a common finding on radiographs and CT imaging. Its presence has been known for more than a century and has been increasing in spine literature during the past 20 years. Although once thought of as an incidental finding, further research may yield important findings about the vacuum phenomenon, which may allow radiologists to understand its meaning more clearly when it is encountered.Learning Objective: The goal of this article is to present the reader with a better understanding of the vacuum phenomenon as it pertains to the lumbar spine and with its history in radiology and surgery literature, its presence in recent literature, and how it may impact spine radiology and surgery moving forward.

Background: Lumbar vacuum phenomenon (VP) within the intervertebral disc has been classified based on CT imaging. We compared same-patient sagittal CT images and dynamic flexion-extension x-rays to determine if there is a difference in the amount of vertebral instability present between three VP morphologies on CT.Methods: Anterior subluxation measurements on x-ray were compared with same-segment VP on CT images from the same patient when both findings were present. VP were classified as spot, island, or linear. It was determined if there was a difference in the amount of anterior subluxation between the three morphologies. Secondary analysis looked at whether there was a difference in anterior subluxation between the three groups if patients had undergone a prior lumbar fusion surgery or not. Results: There was no difference in anterior subluxation between the three groups on dynamic flexion-extension x-rays. There was also no difference between the three groups on flexion-extension x-rays when patients were separated based on if they had received or not received a previous lumbar fusion surgery. Conclusion: IVD VP morphology is not a useful indicator in determining vertebral instability pre-operatively according to CT scan. Further fine-tuning of an IVD VP CT classification is needed to help radiologists and spine surgeons know when IVD VP presence is important.

Introduction As the elderly population of the United States and the world increases, so does the incidence of osteoporotic fragility fractures from a fall or minor injury. This results in a large cost to the health care system. This cost is further increased as more than 50% of individuals will have refractures within the first year. In order to reduce the refracture rate in such patients, we enrolled our elderly trauma patients with vertebral compression fractures and vertebral augmentation in a Fracture Liaison Service (FLS) clinic for two years and reevaluated their refracture rate. Method This is a retrospective analysis of 720 patients. 142 patients (Group A) were seen between 2012 and 2014 before establishing the FLS program and 578 patients (Group B) were seen between 2015 and 2020 after implementation of the FLS program. The patients enrolled in the FLS program were followed for two years after sustaining a vertebral compression fracture. The data collected included age, sex, serum calcium and vitamin D levels, dual energy X-ray absorptiometry (DXA) scan, 10-year fracture risk (FRAX) score, pressure measurements in PSI taken during vertebral augmentation, as well as the refracture rate. The data collected were analyzed and compared between the two groups using the Student’s t-test and chi-square test. Results There was significant reduction in the refracture rate of pre-FLS vs post-FLS vertebral, as well as other fractures in the FLS group (pre-FLS: 48.9% vs post-FLS: 37.0%; P = .01). There was no significant difference between groups A and B in regard to the mean serum level of calcium (9.44 mg/dL vs 9.53 mg/dL), vitamin D level (35.04 ng/mL vs 41.39 ng/mL), DXA scan for spine (−.52 vs −.76) and for femur (−1.77 vs −1.52), and 10-year refracture risk for osteoporotic major fracture (FRAX score-mean: 22.6% vs 19.2%) and for hip fracture (9.18% vs 7.53%). There was a significant difference in the mean age between the groups (79.5 vs 73.5 years; P = .01). Of those who underwent vertebral augmentation, 235 had Pressure Scale Index (PSI) measurements taken. There was a trend in increasing refracture rate when PSI ≤199 compared with those who had PSI ≥200, although statistical significance was not met (33.9% vs 27.0%, P = .21). Conclusion A Fracture Liaison Service program will improve the bone health of geriatric osteoporotic patients presenting to the trauma service with vertebral compression fractures and thus reduces the subsequent refracture rate. Further study is needed to evaluate the best PSI used to impact reduction in refracture rate.