Vol:.(1234567890) European Spine Journal (2018) 27 (Suppl 4):S574–S576 https://doi.org/10.1007/s00586-018-5665-2 1 3 OPEN OPERATING THEATRE (OOT) Spino‑pelvic balance and surgical treatment of L5–S1 isthmic spondylolisthesis Cesare Faldini 1 · Fabrizio Perna 1 · Antonio Mazzotti 1 · Niccolò Stefanini 1 · Giuseppe Geraci 1 · Francesco Traina 1 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Keywords Spino-pelvic parameters · Isthmic · Spondylolisthesis · Dysplastic · Reduction · Sagittal balance · Surgical reduction · Surgical fusion Learning objectives • To explain the principles of spino-pelvic balance; • To show the clinical appearance, physical examination and indication for surgery in high-grade L5–S1 isthmic spondylolisthesis; • To learn anatomy and technique related to severe high dysplastic isthmic spondylolisthesis; • To explain technical tricks when performing a surgical reduction and fusion of a high-grade and high dysplastic isthmic spondylolisthesis. Introduction Spondylolisthesis is defned as the forward slippage of a verte- bra over the underlying one, which typically occurs in the lum- bosacral region. Despite segmental involvement, this pathol- ogy afects the whole biomechanical balance of the spine. Thus, a better defnition could be that spondylolisthesis is the forward slippage of a portion of the spine on the underlying portion [1]. Isthmic spondylolisthesis is the youngster form of slippage which occurs due to pars interarticularis defect and L5–S1 level is the most frequently afected site due to an L5 pars defect. Slippage severity can be easily assessed measuring the percentage of slipping. Consequently, spondylolisthesis can be classifed as low-grade when the slippage is below 50% or high-grade when it exceeds half of the underlying vertebra. Surgery is indicated only in rare cases like: • Demonstrated progression of the slippage; • High slippage degree of spondylolisthesis due to the improved risk of evolution; • Pelvic unbalance; • Low back pain and/or sciatica unresponsive to conserva- tive treatment; • Associated neurological defcits. The role of reduction of the slipped vertebra has been extensively studied and can be evaluated through the analy- sis of the spinopelvic alignment. Aim of these paper and video is to show the surgical proce- dure and technical tricks for the surgical reduction and fusion of a high-grade and high dysplastic isthmic spondylolisthesis by a comprehensive analysis of the spino-pelvic balance. Case description We present the case of a 36-year-old male patient who is sufering of chronic low back pain and non-responsive L5 bilateral radiculopathy. He has been previously subjected to conservative treatment for 6 months without acceptable clinical results. X-rays show a severe unbalanced isthmic spondylolisthesis of L5 that can be classifed as 3rd degree according to Meyerding [1]. Watch surgery online Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00586-018-5665-2) contains supplementary material, which is available to authorized users. * Cesare Faldini cesare.faldini@ior.it 1 Rizzoli Orthopaedic Institute, University of Bologna, Bologna, Italy