Javier Pizones1, Francisco Javier Sánchez Perez-Grueso2, Lucía Moreno-Manzanaro2, Fernando Escámez2, Caglar Yilgor3, Alba Vila-Casademunt4, Nicomedes Fernández-Baíllo2, José Miguel Sánchez-Márquez2, Ibrahim Obeid5, Frank Kleinstück6, Ahmet Alanay3, Ferran Pellisé7. 1. Department of Orthopedic Surgery, Spine Unit, Hospital Universitario La Paz, Paseo de la Castellana 261, 28046, Madrid, Spain. javierpizones@gmail.com. 2. Department of Orthopedic Surgery, Spine Unit, Hospital Universitario La Paz, Paseo de la Castellana 261, 28046, Madrid, Spain. 3. Department of Orthopedics and Traumatology, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey. 4. Spine Research Unit, Vall d'Hebron Institute of Research, Barcelona, Spain. 5. Spine Surgery Unit, Pellegrin University Hospital, Bordeaux, France. 6. Department of Orthopedics, Schulthess Klinik, Zurich, Switzerland. 7. Spine Surgery Unit, Hospital Universitario Vall d'Hebron, Barcelona, Spain.
Abstract
PURPOSE: The compensatory mechanisms recruited by un-instrumented patients against sagittal imbalance are well documented. However, there is a lack of information regarding instrumented patients. MATERIAL AND METHODS: We performed a retrospective analysis of data collected prospectively in a multicenter adult spinal deformity database. We included patients suffering PJK/PJF after (T8-L2) to iliac instrumentation with minimum two-year follow-up. We measured quantitative sagittal spinopelvic and qualitative sagittal distribution parameters in the immediate postoperative period (6w) and at the time of PJK/PJF appearance. We analyzed how these parameters changed comparing these two time points with univariate and multivariate logistic regression analyses. RESULTS: A total of 69 patients were included. Two different patterns at PJK/PJF were found: 36 patients activated compensation (defined as an increase in pelvic retroversion (ΔRPV > 5º), and 33 did not (ΔRPV < 5º). The difference in behavior relied mostly on the amount of not surgically restored pelvic rotation at 6w (OR: 0.6; CI95%: 0.4-9.2; P = 0.017). Non-compensators had less rotation reserve (PTx100/PI = 33.9% vs 47.8%;P < 0.001) associated with worse 6w relative pelvic version and lower lumbar arc restoration, worse 6w relative sagittal alignment and GAP-score, compared with compensators (P < 0.001). Compensators' response was based on pelvic retroversion, causing lower lumbar arc decrease, lumbar apex caudal migration, and upper lumbar arc posterior inclination. Despite compensation, a thoracic kyphosis increase in both upper and lower arches gradually evolved into a PJK/PJF. Non-compensators did not react to PJK/PJF, which forced them into kyphosis from the lumbar apex and extending cranially, mainly throughout the upper thoracic arc. CONCLUSIONS: In patients fused from the TL junction to the iliac, those having greater postoperative pelvic rotation reserve showed greater capacity to recruit compensatory mechanisms against PJK/PJF.
PURPOSE: The compensatory mechanisms recruited by un-instrumented patients against sagittal imbalance are well documented. However, there is a lack of information regarding instrumented patients. MATERIAL AND METHODS: We performed a retrospective analysis of data collected prospectively in a multicenter adult spinal deformity database. We included patients suffering PJK/PJF after (T8-L2) to iliac instrumentation with minimum two-year follow-up. We measured quantitative sagittal spinopelvic and qualitative sagittal distribution parameters in the immediate postoperative period (6w) and at the time of PJK/PJF appearance. We analyzed how these parameters changed comparing these two time points with univariate and multivariate logistic regression analyses. RESULTS: A total of 69 patients were included. Two different patterns at PJK/PJF were found: 36 patients activated compensation (defined as an increase in pelvic retroversion (ΔRPV > 5º), and 33 did not (ΔRPV < 5º). The difference in behavior relied mostly on the amount of not surgically restored pelvic rotation at 6w (OR: 0.6; CI95%: 0.4-9.2; P = 0.017). Non-compensators had less rotation reserve (PTx100/PI = 33.9% vs 47.8%;P < 0.001) associated with worse 6w relative pelvic version and lower lumbar arc restoration, worse 6w relative sagittal alignment and GAP-score, compared with compensators (P < 0.001). Compensators' response was based on pelvic retroversion, causing lower lumbar arc decrease, lumbar apex caudal migration, and upper lumbar arc posterior inclination. Despite compensation, a thoracic kyphosis increase in both upper and lower arches gradually evolved into a PJK/PJF. Non-compensators did not react to PJK/PJF, which forced them into kyphosis from the lumbar apex and extending cranially, mainly throughout the upper thoracic arc. CONCLUSIONS: In patients fused from the TL junction to the iliac, those having greater postoperative pelvic rotation reserve showed greater capacity to recruit compensatory mechanisms against PJK/PJF.
Authors: Caglar Yilgor; Nuray Sogunmez; Louis Boissiere; Yasemin Yavuz; Ibrahim Obeid; Frank Kleinstück; Francisco Javier Sánchez Pérez-Grueso; Emre Acaroglu; Sleiman Haddad; Anne F Mannion; Ferran Pellise; Ahmet Alanay Journal: J Bone Joint Surg Am Date: 2017-10-04 Impact factor: 5.284