Comparison Of The Clinical Effect Of Long-segment And Short-segment Pedicle Screw Fixation For Low Lumbar Fracture And Dislocation

Background and Objective: Amon all spinal fractures, there are only 1% happened at the region of low lumbar(L3-L5). But anatomic and biomechanical characteristics of this region are different from thoracolumbar. Nowadays there are still no unified standards of treating low lumbar fractures, which makes it a controversial issue to chose between short-segment pedicle fixation and long-segment instrumentation. Some studies demonstrated that short-segment instrumentation is the best option for low lumbar fractures because spinal mobility can be persisted and post-operational low back pain and failure rate of intern fixation can be reduced. But other researchers pointed out that short-segment fixation is not strong enough, especially when it is used to treat multi-segmental spinal fractures and unstable lower lumbar fractures, but long-segment instrumentation can obtain good effect at this circumstance. Nowadays, there are no comparative study on short-segment fixation and long-segment instrumentation for low lumbar fractures and dislocation. The goal of this study is to compare short-segment pedicle instrumentation versus long- segment instrumentation for low lumbar fractures.Materials and Methods: We performed a retrospective study from January 2013 to June 2015, 25 cases of low lumbar fracture patients were collected(17 males and 8 females). 10 patients performed long-segment pedicle fixation, and 15 patients performed short-segment instrumentation. The sagittal Cobb ’s angle, anterior vertebral compression and sagittal index, operation time, ASIA neurological classification, low back outcome score(LBOS) were evaluated in all cases.Results: All the patients obtained good outcomes. Long-segment instrumentation group had 1 case of fixation failure while Short-segment fixation group had no fixation failure. There were no statistical differences between the two gropes in preoperative and postoperative sagittal index and anterior vertebralcompression. But when it came to follow-up sagittal index and anterior vertebral compression there were statistical differences between the two gropes. There was significant difference in operation time between the two groups. Long-segment fixation group needed a longer operation time. No patient in any of the two groups had a corrective angle lose more than 10° at the follow-up duration. But compared to long-segment group, short-segment fixation group had a significant larger lose of corrective angle. As to neurological improvement, there was no significant difference for between long-segment fixation and short-segment instrumentation. There was no statistical difference between the two groups in terms of LBOS at the last follow-up time, even if we heard more complains about low back pain in the long-segment group.Conclusions: 1. Compared to short-segment fixation, long-segment instrumentation had better outcomes in terms of maintaining vertebral height, sagittal index and sagittal a Cobb ’s angle. 2.Short-segment fixation could obtain good effect while it is used to treat low lumbar compression fractures and burst fractures. 3.Long-segment fixation need more time to complete than short-segment instrumentation. 4.There is no significant difference for neurological improvement between long-segment fixation and short-segment instrumentation.