Determining the accuracy of lumbar 4/5 pedicle screw entry point based on digital three-dimensional technology / 西安交通大学学报(医学版)

ABSTRACT

【Objective】 To establish a digital model of lumbar 4 and lumbar 5 vertebral bodies through three-dimensional imaging technology so as to explore the precise placement of pedicle screws during the lumbar posterior internal fixation operation. 【Methods】 CT scan image data set of lumbar spine included six specimens. Then lumbar modeling was produced using Mimics software， implanting pedicle screws was simulated with the computer to determine the reliability of pedicle screw for herringbone crest method， Weinstein method， and Magerl method. 【Results】 This study included six specimens （4 males and 2 females）， with an average age of 42.83 years. The distance from the right Magerl entry point to the actual entry point of the lumbar 4 vertebrae was significantly greater than that of the left side. The distance from the left herringbone crest entry point of lumbar 4 vertebrae to the actual entry point was significantly greater than Weinstein method and Magerl method （PMagerl abduction angle > Weinstein abduction angle > herringbone abduction angle. The distances of true-Weinstein and true-herringbone ridges on the left side of lumbar 5 vertebrae were significantly greater than those on the right side （P=0.002 and P=0.004）， and the Weinstein abduction angle on the right side of lumbar 5 vertebrae was greater than that on the left side （P=0.003）. For the left and right sides of lumbar 5 vertebrae， the distance from herringbone crest entry point to the actual entry point was significantly greater than that of Weinstein method and Magerl method （P Magerl abduction angle > Weinstein abduction angle > herringbone abduction angle. 【Conclusion】 Both Weinstein entry point and Magerl entry point for lumbar 4 and lumbar 5 vertebra are close to the real entry point. The Weinstein abduction angle and Magerl abduction angle of lumbar 4 and lumbar 5 vertebrae have minor differences compared with real abduction angle. Therefore， it is recommended that Weinstein method is the preferred choice for lumbar 4 pedicle screw placement， while Weinstein method or Magerl method is the preferred choice for lumbar 5 pedicle screw placement.