LITERATURE REVIEW J Neurosurg Spine 30:211–221, 2019 A ccording to a recent study, low-back pain is the second most common cause of disability in the US 9 and the reported 1-year incidence rate of any low-back pain ranges from 1.6% to 36%. 17 The pathology is also associated with a huge economic burden, with some studies reporting a cost as high as $90.7 billion. 24 As such, there has been much advancement in both nonsurgical and surgical management of common pathologies leading to low-back pain. Among surgical modalities, minimally in- vasive techniques have recently been increasingly adopted by neurosurgeons. 21 A commonly used surgical technique in treating pa- thologies of the spine is transpsoas lateral lumbar inter- body fusion. The technique was frst described by Ozgur et al. in 2006 and has since been endorsed by many spine surgeons. 36 There have been several studies since its frst description highlighting the improved outcomes, ease of access, and lower/comparable complications when com- ABBREVIATIONS GRADE = Grading of Recommendations Assessment, Development and Evaluation; ODI = Oswestry Disability Index; PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses; TP = standalone transpsoas lateral lumbar interbody fusion; TPP = transpsoas lateral lumbar interbody fusion with poste- rior instrumentation; VAS = visual analog scale. SUBMITTED March 30, 2018. ACCEPTED July 10, 2018. INCLUDE WHEN CITING Published online November 2, 2018; DOI: 10.3171/2018.7.SPINE18385. * M.A.A. and R.A. share first authorship of this work. The impact of adding posterior instrumentation to transpsoas lateral fusion: a systematic review and meta-analysis *Mohammed Ali Alvi, MBBS, 1,2 Redab Alkhataybeh, MBBS, 1,2 Waseem Wahood, MS, 1,2 Panagiotis Kerezoudis, MD, MS, 1,2 Sandy Goncalves, MS, 1,2 M. Hassan Murad, MD, MPH, 1–3 and Mohamad Bydon, MD 1,2 1 Mayo Clinic Neuro-Informatics Laboratory, 2 Department of Neurologic Surgery, and 3 Evidence-based Practice Center, Mayo Clinic, Rochester, Minnesota OBJECTIVE Transpsoas lateral interbody fusion is one of the lateral minimally invasive approaches for lumbar spine surgery. Most surgeons insert the interbody cage laterally and then insert pedicle or cortical screw and rod instrumenta- tion posteriorly. However, standalone cages have also been used to avoid posterior instrumentation. To the best of the authors’ knowledge, the literature on comparison of the two approaches is sparse. METHODS The authors performed a systematic review and meta-analysis of the available literature on transpsoas lateral interbody fusion by an electronic search of the PubMed, EMBASE, and Scopus databases using PRISMA guide- lines. They compared patients undergoing transpsoas standalone fusion (TP) with those undergoing transpsoas fusion with posterior instrumentation (TPP). RESULTS A total of 28 studies with 1462 patients were included. Three hundred and seventy-four patients underwent TPP, and 956 patients underwent TP. The mean patient age ranged from 45.7 to 68 years in the TP group, and 50 to 67.7 years in the TPP group. The incidence of reoperation was found to be higher for TP (0.08, 95% confdence interval [CI] 0.04–0.11) compared to TPP (0.03, 95% CI 0.01–0.06; p = 0.057). Similarly, the incidence of cage movement was found to be greater in TP (0.18, 95% CI 0.10–0.26) compared to TPP (0.03, 95% CI 0.00–0.05; p < 0.001). Oswestry Disability Index (ODI) and visual analog scale (VAS) scores and postoperative transient defcits were found to be comparable be- tween the two groups. CONCLUSIONS These results appear to suggest that addition of posterior instrumentation to transpsoas fusion is asso- ciated with decreased reoperations and cage movements. The results of previous systematic reviews and meta-analyses should be reevaluated in light of these results, which seem to suggest that higher reoperation and subsidence rates may be due to the use of the standalone technique. https://thejns.org/doi/abs/10.3171/2018.7.SPINE18385 KEYWORDS transpsoas; XLIF; lumbar fusion; spine surgery; minimally invasive surgery J Neurosurg Spine Volume 30 • February 2019 211 ©AANS 2019, except where prohibited by US copyright law Unauthenticated | Downloaded 07/02/20 12:14 PM UTC