SUMMARY Lytic spondylolis~hcsis .is a common condition and is frequently identified in the adult patient with low back pain. The current premise . is that lytic defect is the result of a fatigue fracture that oc~urs through a congenitally weak or ·deficient pars. If radiologic studies are required,. plain x rays are the basic studies to diagnose and evaluate the condition, however, magnetic resonance imaging IS an essential preoperative investigation. I Despite a . wide array of surgical options . available, nonoperative care continues to be the mainstay and initial focus of treatment for · the -adult with lytic spondylolisthesis. For patients who have persistent complaints of lower back pain, with or without radiculopathY,and who have not responded satisfactorily to nonoperative management, arthrodesis may be indicated. Based on the previous facts, this prospective study was conducted on 50 adult patients, with low grade lytic spondylolisthesis. The protocole of surgical management used in this series consisted of: In situ autogenous posterolateral fusion pedicular fixation using the Oswestry pedicular screw system Gill decompression After an average follow up of 20 months the results obtained from this work are quite satisfactory, with an overall fusion rate of 94%, and a satisfactory, excellent and good clinical outcome in 92%. 149 SUMMARY The results of this study support the reliability of the segmental pedicular fhmtion !Is a safe technique resulting in a satisfactory out come of in situ posterolateral grafting and the consequent clinical outcome. 150