Comparing The Early Efficacies Of Autologous Bone Grafting And Interbody Fusion Cages For Treating Degenerative Lumbar Instability In Patients Of Different Ages

Objective The aim of this study was to compare the early efficacies of interbody bone graft fusion versus interbody fusion cage in degenerative lumbar instability patients of different ages during modified transforaminal lumbar interbody fusion(TLIF).Methods Data of 33 patients with double-segment degenerative lumbar instability, who were treated with modified TLIF combined with posterior fixation system from December 2008 to June 2014 and obtained complete follow-up, were retrospectively analyzed. The two segments separately received interbody bone graft fusion and interbody fusion cage. According to the age, patients were divided into group A(middle-aged and elderly group, ≥ 55 years, n=13) and group B(young adult group, < 55 years, n=20). Clinical efficacies of modified TLIF combined with posterior fixation system were assessed using Japanese Orthopaedic Association(JOA), Oswestry Disability Index(ODI) and Visual Analogue Scale(VAS) before and after surgery and during final follow-up. We measured mean intervertebral space height, intervertebral foramen height, lumbar lordosis angle, and the increased values of mean intervertebral space height and intervertebral foramen height as criteria for image evaluation. Interbody fusion was evaluated using Suk standard.Results Patients in the group A were followed up for(19.15±8.01) months. Patients in the group B were followed up for(14.80±5.47) months. Postoperative JOA, ODI, VAS and lumbar lordosis angle were improved apparently. Moreover, the early clinical follow-up effect was good. In the group A, significant differences in intervertebral foramen height post surgery and during final follow-up, mean intervertebral space height during final follow-up, the increased values of intervertebral foramen height and mean intervertebral space height were detected between the two fusion methods, and no significant difference in other parameters was found. In the group B, significant differences in intervertebral foramen height during final follow-up, and mean intervertebral space height post surgery and during final follow-up were detected between the two fusion methods, and no significant difference in other parameters was found. Both fusion methods reached bony fusion in all cases. Fusion time of autologous bone graft and interbody fusion cage was respectively(5.46±1.20) months and(6.77±1.01) months in the group A,(5.50±1.28) months and(6.35±1.76) months in the group B, showing significant differences.Conclusion At different ages, interbody fusion cage has advantages in maintaining intervertebral space and intervertebral foramen height, but autologous bone graft can rapidly reach bony fusion. Interbody fusion cage is ideal for young adults, and autologous bone graft is ideal for middle-aged and elderly patients during modified TLIF.