Authors: ShunWu Fan ZhiJun Hu FengDong Zhao Xing Zhao Yue Huang Xiangqian Fang
Publish Date: 2009/10/30
Volume: 19, Issue: 2, Pages: 316-324
Abstract
We set out to determine whether a minimally invasive approach for onelevel instrumented posterior lumbar interbody fusion reduced undesirable changes in the multifidus muscle compared to a conventional open approach We also investigated associations between muscle injury during surgery creatinine kinase levels clinical outcome and changes in the multifidus at followup We studied 59 patients treated by one team of surgeons at a single institution minimally invasive approach in 28 and conventional open approach in 31 voluntarily chosen by patients More than 1 year postoperatively all the patients were followed up with the visual analogue scale VAS and Oswestry disability index ODI and 16 patients from each group were evaluated using MRI This enabled the crosssectional area CSA of lean multifidus muscle and the T2 signal intensity ratio of multifidus to psoas muscle to be compared at the operative and adjacent levels The minimally invasive group had less postoperative back pain P 0001 and lower postoperative ODI scores P = 0001 Multifidus atrophy was less in the minimally invasive group P 0001 with mean reductions in CSA of 122 at the operative and 85 at the adjacent levels compared to 368 and 293 in the conventional open group The increase in the multifiduspsoas T2 signal intensity ratio was similarly less marked in the minimally invasive group where values increased by 106 at the operative and 83 at the adjacent levels compared to 344 and 227 in the conventional open group P 0001 These changes in multifidus CSA and T2 signal intensity ratio were significantly correlated with postoperative creatinine kinase levels VAS scores and ODI scores P 001 The minimally invasive approach caused less change in multifidus less postoperative back pain and functional disability than conventional open approach Muscle damage during surgery was significantly correlated with longterm multifidus muscle atrophy and fatty infiltration Furthermore these degenerative changes of multifidus were also significantly correlated with longterm clinical outcome
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