Objectives: Evaluation of the Transpedicular Screw Fixation as a surgical treatment for the degenerative lumber spin stenosis with segmental instability. Methods: A prospective, uncontrolled and interventional study conducted on thirty patients with low back pain and associated sciatica and claudication due to degenerative spinal stenosis and instability between March 2017-August 2018. Pain assessment, dynamic x rays and MRI was done perioperatively. Results: By comparison of pre- and post-operative translational motion, it has been found that more cases tend to be “fixed in plane" with high statistically significant testing (p=0.00677) by using Wilcoxon signed rank. In the same line, angular motion was compared perioperatively with the same test above, it has been found that vertebral line is more fixed as regard angular motion with high statistically significant result (p=0.0074). By comparing both variables to test the existence of good operative results with presence of “changed" vertebral alignment from instable to stable. It has been found that good results were statistically significant associated with changed alignment from moving to unmovable spinal segment (p < 0.0001). Conclusion: Posterolateral pedicle screws insertion for degenerative lumbar spine is a good option for restoration of sagittal balance, decompression of canal stenosis and needs no demanding experience or learning curve to serve patients with lumbar spine stenosis and instability.