Computed Tomography-based Variation of Lumbar Pedicular Morphometry: A Descriptive Study in Indian Population

Computed tomography (CT)-based pedicle measurements are the most accurate indicators depicting the anatomical pedicle morphometry. 14,15The pedicle screw diameter, screw length, and the angle of its insertion are better tailored according to the CT pedicle measurements. 16,17Understanding the dimensions through CT measurements of pedicular inner diameter, outer diameter, and depth (taken along the long axis of the pedicle) measured in IntroductIonLow back pain is the most common orthopedic problem worldwide. 1Spinal pathologies require definitive surgical stabilization in the form of decompression and instrumentation when indicated.Historically, various implants were used, but with invention of the pedicular screw by Dr Roy Camille in 1963, the gold standard for spine stabilization was brought into practice. 2he rationale for choosing the pedicle as the primary site for screw was that the pedicle is the strongest site accessible posteriorly, the bridge between the three columns of the spine, through which a three-dimensional rigid fixation of the vertebra is performed with additional benefit of high biomechanical screw pull-out strength. [3][4]][5][6] The dimensions of pedicles change at each vertebral level and vary according to the sex and age in Indian population and differs from other populations. 7,8The complications associated with the screw implant are nerve root irritation, implant failure and breakage, 9 screw misplacement, lateral wall perforation and pedicular fracture, rod screw disjunction and screw cut out, 9 vascular injury apart from the neurological complications that can result in permanent neurological deficits (up to 3.5%). 10Considering the frequency, fracture of the pedicle is the most important, with an index ranging from 1.7 to 30%, 11 and for minimally invasive surgery is 3-12%. 12To reduce these complications, accurate anatomical information of the orientation and size of lumbar pedicles is necessary. 13