Height Changes of Intervertebral Disc and Neural Foramen after Anterior Lumbar Interbody Fusion in the Lumbar Spine

Abstract

Study design : A prospective clinical study with radiologic assessment was conducted. Objectives : To analyze the height changes of the intervertebral disc and neural foramen and width changes of the neural foramen after anterior lumbar interbody fusion and posterior fixation in the lumbar spine. Summary of Literature Review : Anterior lumbar interbody fusion distracts the height of the intervertebral disc and neural foramen and the width of the neural foramen. Materials and Methods : Minimal anterior lumbar interbody fusion and posterior fixation were performed in 20 cases from January 1999 to January 2001. The measuring factors were the height of the anterior and posterior discs, and the height and width of the neural foramen, measured with a caliper in 1mm reconstructive, computed tomography, sagittal images before and 6 months after anterior lumbar interbody fusion. The factors were independently measured by three different persons. Results : The height of the anterior and posterior discs was increased by mean 32.2% and 40.5%, respectively. The height of the right and left neural foramen was increased by mean 15.7% and 18.3%, respectively. The width of the superior, middle and inferior neural foramen was increased by mean 20.6%, 30.3% and 38.6%, respectively. There were significant increases in all measuring factors after minimal anterior lumbar interbody fusion. Conclusions : Minimal anterior lumbar interbody fusion significantly increased the height of the anterior and posterior intervertebral discs, and the height and width of the neural foramen, and produced neural decompression.