J Neurosurg Spine Volume 23 • September 2015 spine literature review J Neurosurg Spine 23:314–319, 2015 A rthrodesis of the lumbosacral junction is a com- mon surgical procedure used successfully in the treatment of multiple spinal diseases such as scoli- osis and spondylolisthesis. Several techniques to fuse this segment have been described; however, an interbody tech- nique is commonly used. This method has a large surface area for new bone formation, provides anterior column support, and can reestablish the disc height, which can both indirectly decompress the nerve roots and aid in the correction of local and global sagittal alignment. 13 While this procedure can be performed from several different ap- proaches, each requires signifcant mobilization of either neurovascular structures or abdominal viscera, which can lead to signifcant morbidity. 6,7,12,14,22,25,28,32 An understanding of the morbidity associated with tra- ditional spinal exposures led to the emergence of newer minimally invasive techniques. 20,21,23,34 With their newly developed instrumentation and image guidance, such tech- abbreviatioNS ALIF = anterior lumbar interbody fusion; GLMM = generalized linear mixed model; rhBMP-2 = recombinant human bone morphogenetic protein 2. Submitted September 2, 2014. accepted January 8, 2015. iNclude wheN citiNg Published online June 12, 2015; DOI: 10.3171/2015.1.SPINE14900. diScloSure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Dr. Kepler is a board member of the Association of Collaborative Spine Research; is a consultant for Healthgrades Inc.; and has received support from CSRS and NASS for non–study-related clinical or research effort. Dr. Schroeder has received travel support from Medtronic. Dr. Vaccaro receives royalties from DePuy, Medtronic, Stryker Spine, Biomet Spine, Globus, and Aesculap; is a consultant for Gerson Lehrman Group, Guidepoint Global, Medacorp, Globus, Stryker Spine, Stout Medical, Innovative Surgical Design, Ellipse, Expert Testimony, Medtronic, and Orthobullets; owns stock or stock options in Globus Medical, Progressive Spinal Technologies,Advanced Spinal Intellectual Properties, Computational Biodynamics, Stout Medical, Paradigm Spine, Replication Medica, Spinology, Spine Medica, Vertiflex, Small Bone Technologies, Crosscurrent, Syndicom, In Vivo, Flagship Surgical, Location Based Intelligence, Gamma Spine, Cytonics, Bonovo Orthopaedics, Electrocore, RSI, Rothman Institute and Related Properties, Innova- tive Surgical Design, Flow Pharma, and Spinicity; receives research support from Cerapedics and AOSpine; receives royalties or financial support from Elsevier, Thieme, Jaypee, and Taylor & Francis; is on the editorial board of Spine, Journal of Neurosurgery: Spine, Pan Arab Journal of Neurosurgery, and European Spine Journal; is a board member or has a committee appointment with Innovative Surgical Design, Association of Collaborative Spine Research, Spinicity, Progressive Spinal Technologies, Compu- tational Biodynamics, Advanced Spinal Intellectual Properties, Location Based Intelligence, RSI, and Rothman Institute and Related Properties. Axial interbody arthrodesis of the L5–S1 segment: a systematic review of the literature gregory d. Schroeder, md, christopher K. Kepler, md, mba, and alexander r. vaccaro, md, phd Rothman Institute, Thomas Jefferson University, Philadelphia, Pennsylvania obJect The object of this study was to determine the fusion rate and safety profle of an axial interbody arthrodesis of the L5–S1 motion segment. methodS A systematic search of MEDLINE was conducted for literature published between January 1, 2000, and August 17, 2014. All peer-reviewed articles related to the fusion rate of L5–S1 and the safety profle of an axial interbody arthrodesis were evaluated. reSultS Seventy-four articles were identifed, but only 15 (13 case series and 2 retrospective cohort studies) met the study inclusion criteria. The overall pseudarthrosis rate at L5–S1 was 6.9%, and the rate of all other complications was 12.9%. A total of 14.4% of patients required additional surgery, and the infection rate was 5.4%. Deformity studies reported a signifcantly increased rate of complications (46.3%), and prospectively collected data demonstrated signif- cantly higher complication (36.8%) and revision (22.6%) rates. Lastly, studies with a confict of interest reported lower complication rates (12.4%). coNcluSioNS A systematic review of the literature indicates that an axial interbody fusion performed at the lumbo- sacral junction is associated with a high fusion rate (93.15%) and an acceptable complication rate (12.90%). However, these results are based mainly on retrospective case series by authors with a confict of interest. The limited prospective data available indicate that the actual fusion rate may be lower and the complication rate may be higher than currently reported. http://thejns.org/doi/abs/10.3171/2015.1.SPINE14900 Key wordS axial interbody arthrodesis; systematic review; Axialif; L5–S1 fusion; lumbar 314 ©AANS, 2015