Author(s): Rao PJ, Maharaj MM, Phan K, Lakshan Abeygunasekara M, Mobbs RJ
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Abstract BACKGROUND CONTEXT: A frequently quoted advantage of anterior lumbar interbody fusion (ALIF) is indirect foraminal decompression, although there are few studies substantiating this statement. Also, there are no clinical studies using a standardized method to measure the foraminal area (FA) and the correlation with disc height (DH) parameters. This study is proposed to measure the degree of indirect foraminal decompression radiologically using a standardized method and correlate with the intervertebral disc parameters. PURPOSE: To standardize the foramen measurement technique. To measure indirect neural foraminal decompression in surgically operated patients after ALIF using radiographic measurement and elucidate factors affecting foraminal restoration. STUDY DESIGN: A prospective cohort study. PATIENT SAMPLE: A continuous cohort of patients undergoing ALIF surgery. OUTCOME MEASURES: It included FA, foraminal height (FH), and foraminal width. METHODS: This is a prospective analysis of a single surgeon series of consecutive patients undergoing an ALIF from 2011 to 2013. Pre- and postoperative computed tomography scans were used to obtain a standardized foramen snapshot using the pedicle-to-pedicle (P-P) technique, and measurements were obtained using image j software. Radiologic parameters such as DH, local disc angle (LDA), and lumbar lordosis (LL) were measured using radiographs and Surgimap software. RESULTS: One-hundred forty patients with 184 levels were operated. Anterior lumbar interbody fusion resulted in a statistically significant (p<.01) improvement in foraminal dimensions (area=67\%, height=21\%, and width=38\%). Other parameters also significantly improved, including anterior DH (90\%), posterior DH (77\%), LDA, and LL (6\%). Posterior DH correlated significantly with FH improvement. Statistically, the P-P technique presented with high intra- and interclass reliabilities. CONCLUSIONS: Anterior lumbar interbody fusion results in significant indirect foraminal decompression based on the new P-P technique. Posterior DH is a significant factor in the restoration of the FH. Copyright © 2015 Elsevier Inc. All rights reserved.
This article was published in Spine J
and referenced in Journal of Spine