Anales de la RANM

187 A N A L E S R A N M R E V I S T A F U N D A D A E N 1 8 7 9 THORACOLUMBAR ROTATIONAL KYPHOSIS Pizones J, et al. An RANM. 2022;139(02): 186 - 195 In the past decade, there has been increasing interest in the study of adult spinal deformity. Patients with this condition may have pain, disability, mental health problems, and concerns about their physical appearance. Surgery has been demonstrated to be effective in treating spinal deformity. Controlling both coronal and sagittal deformity and addressing the degenerative changes that cause pain can relieve symptoms and improve patient reported outcome measures. Sagittal plane correction has been the focus of much study, as it seems to be the most influential parameter on clinical symptoms. Surgical planning should aim to restore sagittal balance and the ideal parameters of healthy individuals. Thoracolumbar (TL) scoliosis is often associated with rotational or transitional thoracolumbar kyphosis (TLK). When the apex of the coronal curve is located at the thoracolumbar junction, the rotation created by the axial plane deformity often draws a false kyphosis at this segment, as seen on plain lateral radiograph [1]. The surgical correc- tion of scoliosis in one plane leads to correction of the other planes by coupling effect [2]. Thus, when translating the coronal plane and derota- ting the axial plane, the sagittal plane automati- cally flattens [3]. This rotational kyphosis decrease at the TL junction should produce lordosis at the upper lumbar arc, migration of the inflexion point to a more cranial location, and should add more vertebrae into the global lordosis [4], eventually modifying the preexisting lordosis distribution [5]. The sagittal plane of healthy adults varies by pelvic anatomy and sacral inclination [6, 7]. We know that adult scoliosis (AS) can distort the ideal sagittal profile [8], and one of the goals of surgery should be to restore the proper sagittal shape and lumbar distribution to prevent mechanical complications [9]. Typical mechanical complica- tions are rod breakage due to pseudoarthrosis, proximal junctional kyphosis and screw pull-out or loosening. Little is known about the role of TLK in this process. What impact does surgery have on the sagittal profile of patients with scoliosis who have TL rotational kyphosis? How much does this change affect the sagittal plane matching its ideal type and the outcome in terms of mechanical failure? Do results differ when flattening the upper lumbar arch between patients with low vs high pelvic incidence (PI)? The aim of our study was to analyze a cohort of adult surgical patients with scoliosis and thoracolumbar rotational kyphosis, to understand how the lateral projection of this segment changes after surgery, what impact this change has on lumbar sagittal distribution and ideal sagittal plane matching, and its consequences on mechanical complications. We conducted a retrospective analysis of prospec- tively collected data from a multicenter adult deformity database European Spine Study Group (EESG). Database enrollment criteria were age ≥ 18 years and at least 1 of the following: coronal Cobb angle of ≥ 20°, sagittal vertical axis of ≥ 5 cm, pelvic tilt of ≥ 25°, and thoracic kyphosis of ≥ 60°. Institutional review board approval was obtained at each site for patient enrollment and data collection protocols. All patients signed an informed consent prior to enrollment. The inclusion criteria for this specific study were surgical patients with AS and a TL/L curve > 30° (double or single TL/L curves), T10-L2 sagittal kyphosis defined as (TLK) > 20°, and at least a 2-year follow-up. We analyzed the following preoperative and 2-year postoperative coronal and sagittal radiographic parameters: coronal TL Cobb angle, TL coronal translation (measured from the TL coronal apex to the central sacral vertical line), thoracolumbar kyphosis (TLK) (T10-L2), maximal lumbar lordosis (MaxLL) (measured from the inflection point to S1 endplate), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), inflection point (where kyphosis transitions to lordosis) [5], type of Roussouly sagittal shape (R-type), and the location of the upper and lower instrumented vertebra (UIV and LIV). INTRODUC TION MATERIAL AND METHODS Incidencia Pélvica. Este cambio sagital TL no se asociaba directamente a complica- ciones o al desajuste del perfil ideal. Las complicaciones mecánicas sólo se asociaban a mayor edad e instrumentación hasta la pelvis. Comparando pacientes con PI alta y baja la corrección del Cobb fue similar, al igual que la corrección de la CTL y el porcentaje de complicaciones mecánicas. Resultó más difícil restaurar el plano sagital ideal en pacientes con PI-alta y aquellos fusionados a la pelvis. Conclusiones: La corrección quirúrgica de la escoliosis TL aplana el segmento TL unos 20°, automáticamente ajustándose a los parámetros dictados por la incidencia pélvica. Este cambio TL alarga el arco lumbar superior en un segmento, trasladando el punto de inflexión a craneal. Sin embargo, este cambio no tuvo un impacto directo en las complicaciones mecánicas o el ajuste final del perfil sagital.