Radiologic Adjacent Segment Degeneration: Two Levels fusion (L3-4-5 and L4-5-S1) Using Percutaneous Pedicle Screw Fixation in Degenerative Lumbar Spinal Disease; A Preliminary Report

ABSTRACT

OBJECTIVE: The purpose of this study is to examine radiological adjacent segment degeneration (ASD) and clinical results after two levels percutaneous pedicle screw fixation. METHODS: From 2007 to 2009, 34 patients who underwent percutaneous pedicle screw fixation on L3-4-5 or L4-5-S1 for lumbar degenerative disorders were selected. According to the presence of radiological ASD, ASD group and non-ASD group were compared for clinical results and radiologic results such as total lordotic angle (TLA), segmental lordotic angle (SLA) via lumbar X-rays during follow up periods. Furthermore, we compared pre-operative degree of disc degeneration at adjacent segment between two groups via MRI. RESULTS: The mean follow-up period and mean age were 27.38+/-9.45 months and 59.21+/-12.73 years. ASD group were 7 patients, and non-ASD group were 27 patients. The mean age of the ASD group (67.40+/-4.81) was significantly older than that of the non-ASD group (57.46+/-13.18). Pre-operative disc degeneration of cranial adjacent segment in ASD group were 6 patients (25.9%), whereas that in non-ASD group were 4 patients (14.8%), showing that preoperative disc degeneration was significantly more severe in the ASD group. CONCLUSION: Percutaneous pedicle screw fixation is favorable technique to prevent ASD for two levels fusion, however, when the patient is old or the preoperative disc degeneration of the adjacent segment is severe, there is the risk of postoperative ASD, and thus special attention should be paid during the follow-up period.