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A Radiographic Assessment of the Ability of the Extreme Lateral Interbody Fusion Procedure to Indirectly Decompress the Neural Elements

Oliveira, Leonardo BSc*; Marchi, Luis MSc*; Coutinho, Etevaldo MD*; Pimenta, Luiz MD, PhD

doi: 10.1097/BRS.0b013e3182022db0

Study Design. Prospective nonrandomized clinical study on the decompressive effect of the extreme lateral interbody fusion (XLIF) procedure.

Objective. This study evaluates the results of interbody distraction from a lateral retroperitoneal approach for the treatment of lumbar degenerative conditions inclusive of central and/or lateral stenosis.

Summary of Background Data. Traditional treatment for symptomatic lumbar stenosis has been by direct posterior decompression (i.e., removal of ligamentum flavum, laminotomy/laminectomy, facetectomy, as needed). Stenotic symptoms may also be alleviated indirectly, through correction of intervertebral and foraminal height and correction of spinal alignment. Anterior-only spinal procedures rely on this indirect decompression when used in patients with radicular symptoms.

Methods. Consecutive patients presenting with degenerative conditions that included concomitant lumbar stenosis were consented and treated via stand-alone XLIF. Pre- and postoperative radiographic measurements were made from plain lateral radiographs and sagittal and axial magnetic resonance imaging views by an independent radiologist using medical imaging software. Measurements included disc height, foraminal height, foraminal area, and canal diameter.

Results. In all, 7 male and 14 female patients (mean age, 67.6 years; range, 40–83) underwent XLIF at 43 lumbar levels in an average operative time of 47 minutes and with an average 23 mL estimated blood loss per level. There were no intraoperative complications. Mean hospital stay was 29.5 hours. Transient postoperative psoas weakness occurred in 3 (14.3%) of the cases. Substantial dimensional improvement was evidenced in all radiographic parameters, with increases of 41.9% in average disc height, 13.5% in foraminal height, 24.7% in foraminal area, and 33.1% in central canal diameter. Two patients (9.5%) required a second procedure for additional posterior decompression and/or instrumentation.

Conclusion. The XLIF procedure provides the necessary decompression for the treatment of central and/orlateral stenosis in a minimally disruptive way, avoiding, in most cases, the need for the direct resection of posterior elements and associated morbidities. Indirect decompression may be limited in cases of congenital stenosis and/or locked facets. Its effect may also be reduced by postoperative subsidence and/or loss of correction.

A prospective radiographic evaluation of the immediate indirect decompressive effect of the lateral interbody procedure demonstrates that central and/or lateral stenosis can be relieved less invasively, avoiding in most cases the need for the direct resection of posterior elements and associated morbidities.

From the *Instituto de Patologia de Coluna, São Paulo, Brazil; and †Department of Neurosurgery, University of California San Diego, San Diego, CA.

Acknowledgment date: August 19, 2010. First revision date: September 27, 2010. Second revision date: October 14, 2010. Acceptance date: October 15, 2010.

Supported by NuVasive, Inc. financially and materially in the form of coverage for nonreimbursable study-related imaging costs and provision of devices.

The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication. Corporate/Industry funds were received to support this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Address correspondence and reprint requests to Leonardo Oliveira, BSc, Instituto de Patologia da Coluna, Rua Vergueiro, 1421-Sala 305. São Paulo, Brazil 04101000; E-mail:

© 2010 Lippincott Williams & Wilkins, Inc.