Systematic Review of Reciprocal Changes after Spinal Reconstruction Surgery : Do Not Miss the Forest for the Trees

Abstract

The purpose of this review was to synthesize the research on global spinal alignment and reciprocal changes following cervical or thoracolumbar reconstruction surgery. We carried out a search of PubMed, EMBASE, and Cochrane Library for studies through May 2020, and ultimately included 11 articles. The optimal goal of a truly balanced spine is to maintain the head over the femoral heads. When spinal imbalance occurs, the human body reacts through various compensatory mechanisms to maintain the head over the pelvis and to retain a horizontal gaze. Historically, deformity correction has focused on correcting scoliosis and preventing scoliotic curve progression. Following substantial correction of a spinal deformity, reciprocal changes take place in the flexible segments proximal and distal to the area of correction. Restoration of lumbar lordosis following surgery to correct a thoracolumbar deformity induces reciprocal changes in T1 slope, cervical lordosis, pelvic shift, and lower extremity parameters. Patients with cervical kyphosis exhibit different patterns of reciprocal changes depending on whether they have head-balanced or trunk-balanced kyphosis. These reciprocal changes should be considered to in order to prevent secondary spine disorders. We emphasize the importance of evaluating the global spinal alignment to assess postoperative changes.

Reciprocal Changes in the Whole-Body Following Realignment Surgery in Adult Spinal Deformity

“…Achieving the optimal alignment leads to potential improvements in the clinical outcomes. The patient’s degree of disability rises with a positive global malalignment following the surgical correction of a deformity [ 8 , 36 , 39 ]. Cervical alignment parameters such as: C2–7 SVA and T1S–CL are positively correlated with the HRQoL [ 22 , 61 , 63 , 65 ].…”

“…Several compensatory mechanisms have been implemented to maintain the optimal GSA, including increased CL, PT, ankle flexion, and the knee flexion (Fig. 1) [39][40][41]. The aging-related deterioration of the GSA is compensated by supportive functions of the spine, pelvis, and the lower limbs [30].…”

“…Accordingly, all the elements of the chain of balance considered to evaluate the static global balance [ 41 ]. However, it is difficult to use the conventional radiographs to assess the lower extremities or head position [ 39 ]. Therefore, using the preoperative EOS evaluation aids full-body analysis of a patient, leading to an optimal preoperative planning.…”

Postoperative Gravity Line-Hip Axis Offset as a Substantial Risk Factor for Mechanical Failure After Adult Spinal Deformity Correction Surgery

“…22 The need has arisen for a perspective to better understand spinal balance that also incorporates unfused spinal segments with a dynamic compensatory capacity and the chance of further degeneration. 23,24 Even healthy disks located below the LIV in patients with adolescent idiopathic scoliosis can degenerate, which is reflected in the debate about how to select the LIV and its impact on the consequence of adding-on phenomena or distal junctional kyphosis. [25][26][27] Since its emergence in 2005, C7-SVA has been considered to represent sagittal balance, which encompasses various radiographic parameters of the thoracolumbar spine.…”

Modeling as a Method for Studying Mechanogenesis Angular Kyphotic Deformities of the Spine

“…Степень использования математических методов в медицине характеризует глубину знаний по изучаемому предмету [3]. Не вызывает сомнения тот факт, что при возникновении патологии позвоночника его форма и пространственная ориентация изменяются [6]. Процесс формирования деформации всего позвоночника инициируется возникновением локальных изменений в двигательном сегменте позвоночника и дополняется ответными реакциями со стороны интактных сегментов позвоночника и суставов нижних конечностей [7].…”