Vertebral Bone Quality and Prediction of Screw Loosening in Spine Fusion

Study Overview
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Brief Summary
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Finding a way to use Vertebral CT scan will help to predict screw loosing risk in spinal fusion for degenerative spine disease. Patients who will undergo at least two spine fusion levels for degenerative spine disease will be enrolled in. Before surgery, patients will undergo a spinal QCT scan with a calibrated phantom. The calibrated bone density, at bone-implant interface, will be assessed using dual energy CT scan immediately after surgery, and six months later. The primary outcomes will be the difference between the two values of the bone implant interface. The difference between density values will be correlated to the pre-op bone density value.

Detailed Description
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Screw loosening is a real problem in degenerative spine surgery because of the morbidity of secondary surgery sometimes needed for elderly patients. Today, there is no real possibility to know before surgery if cemented screws are needed or not. The use of cemented screws has its morbidity. In fact, bone densitometry is not a good exam to predict the bone quality in degenerative spine because of the arthritis. T-score in degenerative spine can be overestimated. The goal of our study is analyze the bone-implant interface after spine fusion using dual-energy CT scan technology which can provide pictures without artifact compared to standard CT scan. This is a prospective observational monocentric study. Patients over 18 years old and have undergone at least two primary spine fusion levels will be enrolled. The exclusion criteria are the use of cemented screws, secondary surgery and neurodegenerative disease. The primary outcome will be the change in the bone-implant interface at six months post-surgery compared to the interface after surgery. The change will be assessed by calibrated dual CT scan. The interface bone density will be assessed using calibrated scans, and correlate to the true vertebral bone density measured before surgery with a QCT. We hope that this study can provide a simple and reproducible help for surgeons to choose between uncommented and cemented screws for their spine fusions surgeries.

Official Title
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Vertebral Bone Quality and Prediction of Screw Loosening in Spine Fusion

Conditions
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Spine Fusion for Degenerative Spine Disease

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: More than 18 years old needed a minimum 2 levels spinal fusion agreed protocol Exclusion Criteria: Cimented pedicular screws secondary surgery neurodegenerative disease

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of bone-implant interface at 6-month follow up compared to post operative interface assessed on Dual energy CT Scan | Assessment of bone-implant interface (1 to 3 mm around the screw) using calibrated bone density on spinal dual energy CT scan just after surgery and at 6 months of follow up. Comparison between the two measured values. | 6 montths | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| evolution of bone density of non instrumented levels between T0 and 6 months follow up assessed with Dual Energy CT scan |  | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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degenerative spine disease, screw loosening, Quantitative CT scan, vertebral bone density