Comparison of pedicle fixation by the Wiltse approach and the conventional posterior open approach for thoracolumbar fractures, using MRI, histological and electrophysiological analyses of the multifidus muscle
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To use imaging, histology and electrophysiological assessment to compare the Wiltse approach to pedicle fixation with the conventional posterior open approach for thoracolumbar fractures.
We analyzed clinical and histopathological information of consecutive patients with thoracolumbar fractures who underwent short-segment pedicle fixation using either the Wiltse approach or the posterior open approach. Seventy-five patients were enrolled between June 2010 and August 2014 (Wiltse group 35 cases; posterior open group 40 cases). The two groups were compared for MRI appearance, histological and electrophysiological changes in multifidus muscle.
On MRI, multifidus cross-sectional area (CSA) in the Wiltse group decreased by only 7.6% between pre-op and the last follow-up, compared to 35.4% in the posterior open group, and less fatty infiltration was found in the Wiltse group. Histologically, post-op (removal of internal fixation) tissue from the posterior open group showed disordered myofibrils, with diameter and CSA decreased by 11.6 and 24.3%, respectively; also, the myofibril gap became larger with fat deposition and scar formation. The Wiltse group had no such significant changes. Electrophysiologically, in the posterior open group, median frequency slope (MFs) significantly increased by 67.6% with average amplitude (AA) significantly decreased by 17.5% between pre-op and 12 months post-op. No significant changes were found in the Wiltse group. At 12 months post-op, AA was significantly lower and MFs was higher in the posterior open group than the Wiltse group.
The Wiltse approach showed a lower incidence of multifidus atrophy and denervation, and less fatty infiltration. It is an effective and minimally invasive approach for thoracolumbar fractures.
KeywordsMultifidus muscle Wiltse approach Thoracolumbar fractures Conventional posterior open approach
The authors wish to express their gratitude to Prof. Michael Adams and Dr. Patricia Dolan for help with the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
National Natural Science Foundation of China (project number: 31270997); Zhejiang Medical and Health Science and Technology project: (project number: 2016136915, 2013KYA2334).
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