Analysis of Risk Factors of Cement Leakage in Vertebroplasty
Date Issued
2008
Date
2008
Author(s)
Ou, Jen-Kai
Abstract
Objective: To investigate the effect of cement viscosity, bone mineral density, and fracture level on the injection force and on the cement spreading pattern within the vertebrae during percutaneous vertebroplasty.ummary of Background Data: Vertebroplasty is a minimal invasive surgery for spinal compression fracture. Cement viscosity, bone mineral density, and fracture level have been suspected to influence the injection force and spreading pattern of the cement; hence, further affect the risk of cement leakage.aterials and Methods: Two experiments were conducted in this study. The first one was to find the effect of bone structure, bone porosity, and viscosity on the injection force and spreading patterns of the silicon oil. Three types of sawbones (BMD= 0.33 g/cm2, open cell; BMD= 0.53 g/cm2, open cell; BMD= 1.18 g/cm2, closed cell) and silicon oil (η=30, 60, 100 Pa*s ) were used. The second experiment was to find the effect of the fracture level and the cement viscosity on the injection force and spreading pattern of the bone cement. Ten cadaveric thoracic vertebrae were compressed to 30% of original height, and another 10 vertebrae were compressed to 60% of original height. Two kinds of bone cement with different viscosity were made by setting the powder-monomer ratio to be 1.3 and 1.6. In the first and the second experiment, 3 mL of silicon oil and bone cement was injected into the specimen at speed of 1.62 mL/min using the standard vertebroplasty procedure. The process of bone deformation and silicon oil /cement injection was scanned using cine-CT. The spreading patterns of silicone oil / bone cement within the sawbones and vertebrae were analyzed with an in-house image processing software. The specimens were sliced to find the spreading patterns and leakage pathway. The parameters that significantly influenced the injection force were determined by one-way ANOVA.esults: In the first experiment, the injection force increased with viscosity of silicone oil. The injection force was 31(10) N for 30 Pa*s, 63(4) N for 60 Pa*s, and 81(12) N for 100 Pa*s silicone oil. The porosity and structure of sawbones did not affect the injection force. The spreading patterns of silicon oil were “bulb”shape within low- and median-density sawbones, but spreading patterns were irregular within high-density sawbones. In the second experiment, injection force also increased with viscosity of bone cement. The injection force was 208(39) N for high viscosity and 115(38) N for low viscosity. Bone mineral density and fracture level did not affect the injection force. The incidence of cement leakage increased with level of fracture. The cement was leaked in 3 out of 10 low fractured specimens, while all cement was leaked in high fractured specimens. The leakage pathway included fractured site of cortical shell, endplate fissure, basivertebral foramina and needle track. Bone mineral density and cement viscosity did not affect the cement leakage. The lower viscous cement spread wider and further in the vertebrae with lower fracture level. The height of vertebrae was recovered significantly after the vertebroplasty.onclusion: The injection force increases with viscosity of bone cement. The incidence of cement leakage is highly related to the level of fracture, while the fractured cortical shell, endplate fissures, basivertebral foramina and needle track are possible leakage sites. For the vertebrae without defects on cortical surface, injecting lower viscous cement is suggested, because the injection force is lower and the cement will not leak out of the vertebrae. For the vertebrae with defects on cortical surface, injecting higher viscous cement, keeping the injection track away from the defects and stopping injection when cement reaches the defects are suggested to avoid leakage.Keyword】osteoporosis, compression fracture, vertebroplasty, bone cement, leakage, injection force
Subjects
osteoporosis
compression fracture
vertebroplasty
bone cement
leakage
injection force
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95548013-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):36149070a5ec10cb798e9980bca2b0d5