Evidence showing the relationship between sagittal balance and clinical outcomes in surgical treatment of degenerative spinal diseases: a literature review

Abstract

The measure of radiographic pelvic and spinal parameters for sagittal balance analysis has gained importance in reconstructive surgery of the spine and particularly in degenerative spinal diseases (DSD). Fusion in the lumbar spine may result in loss of lumbar lordosis (LL), with possible compensatory mechanisms: decreased sacral slope (SS), increased pelvic tilt (PT) and decreased thoracic kyphosis (TK). An increase in PT after surgery is correlated with postoperative back pain. A decreased SS and/or abnormal sagittal vertical axis (SVA) after fusion have a higher risk of adjacent segment degeneration. High pelvic incidence (PI) increases the risk of sagittal imbalance after spine fusion and is a predictive factor for degenerative spondylolisthesis. Restoration of a normal PT after surgery is correlated with good clinical outcome. Therefore, there is a need for comparative prospective studies that include pre-and postoperative spinopelvic parameters and compare complication rate, degree of disability, pain and quality of life.

Importance of balance and profile in adult spinal reconstruction

“…Fortunately, the translation of this pioneering work into practical guidelines led to increasingly common reports on how the sagittal profile impacts on daily living of affected patients, and this trend does not seem to stop on either sides of the Atlantic Ocean [2,3,9] . Many are the parameters of spinal balance described so forth [4] , but three deserve particular attention, i.e., Pelvic Incidence (PI), Pelvic Tilt (PT) and Sacral Slope (SS).…”

“…These four types are rather simple keep in mind and should be used as a reference template in planning osteotomies and correction of ASD, in order to respect the original shape, i.e., profile, of the individual spine [3,4] . In a simplistic way, the last important concept is that 70% of all lumbar lordosis, irrespective of the spinal profile, is concentrated between L4 and S1.…”

“…It became progressively apparent and accepted that patients undergoing fusion for degenerative deformities did not do well when their sagittal rather than coronal balance was less than restored [2] . Alleged reasons for these failures included natural history [3] , junctional degeneration [4] and bone-implant interface failure [5] to name a few. It was only when surgeons started to learn the rules of spino-pelvic parameters and to apply them to patients that reports on adult spinal deformity surgery changed their grim faces into a more optimistic appearance [6] .…”

“…We analysed English edited papers on ASD surgery through PubMed in the years 2000-2014 with attention to parameters that closely related to surgical outcomes [2][3][4][5][6][7][8][9] . Eleven papers were included in the analysis because of their clinical relevance to the subject [2][3][4][5][6][7][8][9][10][11][12] .…”

“…Eleven papers were included in the analysis because of their clinical relevance to the subject [2][3][4][5][6][7][8][9][10][11][12] . All of them are retrospective case series or reviews limiting the value of their evidence to lower levels.…”