George D C, Krag M H, Johnson C C, Van Hal M E, Haugh L D, Grobler L J
Department of Orthopaedics and Rehabilitation, McClure Musculoskeletal Research Center, University of Vermont College of Medicine, Burlington.
Spine (Phila Pa 1976). 1991 Feb;16(2):181-4.
In each of eight thoracolumbar human cadaveric vertebrae, a hole was made through one pedicle into the vertebral body with a drill bit and through the contralateral pedicle with a probe. Identical metal screws were implanted into the holes to equal depths, and maximum pull-out force was determined for each screw. Using a paired Student t test, no significant difference (P = 0.87) was found in pull-out strength between the screws implanted into drilled holes and those implanted into probed holes. In fact, the average pull-out strengths for the two groups differed by less than 2%. The pedicular cortex was broken through during hole preparation in 5 of the 16 pedicles: 3 as a result of drilling and 2 secondary to probing. The average pull-out strength of the screws in these five pedicles was 11.0% less than the average pull-out strength of the screws implanted into the contralateral intact pedicles. Although this does not represent a statistically significant difference (P = 0.15), it suggests that damaging the pedicular cortex may weaken pedicle screw fixation.
在八个胸腰椎人尸体椎骨中，用钻头在每个椎骨的一个椎弓根上钻孔并穿透椎体，并用探针穿过对侧椎弓根。将相同的金属螺钉植入孔中至相同深度，并测定每个螺钉的最大拔出力。使用配对学生t检验，发现钻入孔中的螺钉与探针孔中植入的螺钉之间的拔出强度无显著差异（P = 0.87）。实际上，两组的平均拔出强度相差不到2%。在16个椎弓根中的5个椎弓根准备孔的过程中，椎弓根皮质被穿透：3个是由于钻孔，2个是由于探针操作。这五个椎弓根中螺钉的平均拔出强度比植入对侧完整椎弓根的螺钉的平均拔出强度低11.0%。虽然这在统计学上没有显著差异（P = 0.15），但表明破坏椎弓根皮质可能会削弱椎弓根螺钉固定。
