Abstract
Introduction
The knowledge of the pedicle size in the lumbar vertebrae is important for safe and effective placement of screws in cases of instrumentation in this region. This importance is even more relevant when it is about fixing through a minimally invasive way. Most of the minimally invasive techniques for lumbar spine instrumentation is described recommending parameters for introduction of pedicle screws (25mm) based on measurement of the pedicle length in model populations (North American / European mostly). It is our purpose in this work to establish the morphometric parameters of the lumbar vertebrae pedicles in the Brazilian population, which has no such parameters well studied yet.
Material and Methods
Cross-sectional study of 100 adult patients (between 26 and 90 years old), 50 males and 50 females (all without trauma, tumor, inflammatory / infectious diseases or post-surgical condition) who underwent simple tomography of the lumbar spine from January to December 2012 at the Institute of Radiology of the Hospital of São Paulo in Brazil, 1000 pedicles of lumbar vertebrae were evaluated. And Literature Review conducted by PUBMED by Keyword: Lumbar Spine pedicles
Results
We describe for each lumbar level (L1 through L5) two measure: (Measurements made for both sides (left / right) of each pedicle): Measure A (length of the longitudinal axis of the pedicle base to the intersection of 90 ° with the imaginary line that goes from the anterior border of the spinal foramen) / Measure B (length of the longest longitudinal axis of the pedicle, the base to the junction with the anterior cortex of the vertebral body, line tangential to the spinal foramen and without crossing the midline). Measurements were obtained by electronic measurement system in iSITE Radiology in the axial plane of the major axis of each pedicle on CT scans without contrast cut standard 0.5mm Based on this assessment, we noticed that the average measure (to measure A) of the pedicles in the studied population was 17,12mm to L1, L2 to 16,22mm, 15,40mm to L3, 14,83mm to L4, L5 to 14,64mm
Conclusion
Thus the measure advocated for introduction of pedicle screws in minimally invasive techniques is appropriate for this population