The Effect of Additional Transpedicular Instrumentation for Patients with Symptomatic Degenerative Spondylosis with Instability Treated with Posterior Lumbar Interbody Fusion Using Autologous Iliac Bone Dowels

ABSTRACT

OBJECTIVE: The purpose of this study is to determine whether the additional transpedicular instrumentation improves the clinical outcome and fusion rate of patients undergoing posterior lumbar interbody fusion with autologous iliac bone dowels after decompression for spinal stenosis with spondylolisthesis or instability. METHODS: Among 51 patients who had symptomatic spondylolisthesis or instability with stenosis, 24 patients underwent decompressive laminectomy and interbody graft with autologous iliac bone dowels (Group A) and 27 patients had additional transpedicluar instrumentation after decompression and interbody fusion(Group B). Patients were followed up for more than two years after the operation and meanwhile change of the symptoms, patient's satisfaction, fusion rates and surgical complications were checked. RESULTS: Mean age(year), duration of the symptoms(months), and follow-up period(months) of the two groups were 47, 42, 42 and 51, 86, 32 respectively. Seventy-nine percent in Group A and 86% in Group B reported good to excellent clinical outcomes. Successful interbody fusion was accomplished in 50% in Group A and 87% in Group B(p<0.001). Anterior slippage correction rates were 40%(Group A) and 45%(Group B). Complications occurred in 5 cases of Group A(2 donor site pain, 3 reoperations) and 9 cases of Group B(5 donor site pain, 3 reoperations, 1 screw fracture). CONCLUSION: In patients undergoing one or two level interbody bone graft for symptomatic spondylolis-thesis or instability, the use of pedicle screws improve the fusion rates, but do not necessarily guarantee favorable clinical outcome and may increase the complication rates with instrumentation. Pedicle screw fixation procedure need to be selected cautiously in symptomatic degenerative spondylosis patients.