TY - JOUR
T1 - Global sagittal axis
T2 - A step toward full-body assessment of sagittal plane deformity in the human body
AU - Diebo, Bassel G.
AU - Oren, Jonathan H.
AU - Challier, Vincent
AU - Lafage, Renaud
AU - Ferrero, Emmanuelle
AU - Liu, Shian
AU - Vira, Shaleen
AU - Spiegel, Matthew Adam
AU - Harris, Bradley Yates
AU - Liabaud, Barthelemy
AU - Henry, Jensen K.
AU - Errico, Thomas J.
AU - Schwab, Frank J.
AU - Lafage, Virginie
N1 - Funding Information:
Dr. Schwab has direct stock ownership in Nemaris, Inc., and is a consultant for K2M, Medicrea, NuVasive, Zimmer-Biomet, and MSD. He has speaking/teaching arrangements with K2M, Medicrea, NuVasive, Zimmer-Biomet, and MSD. Dr. Schwab has received clinical or research support from SRS, AO, DePuy Spine, and Syntesis. He is a patent holder for MSD and K2M. Dr. Lafage has direct stock ownership in Nemaris, Inc., and is a consultant for NuVasive. Dr. Lafage has received clinical or research support from SRS, NIH, and DePuy Spine Synthesis. She has speaking/teaching arrangements with Medicrea, NuVasive, DePuy Spine, and Nemaris, Inc.
Publisher Copyright:
©AANS, 2016.
PY - 2016/10
Y1 - 2016/10
N2 - OBJECTIVE: Sagittal malalignment requires higher energy expenditure to maintain an erect posture. Because the clinical impact of sagittal alignment is affected by both the severity of the deformity and recruitment of compensatory mechanisms, it is important to investigate new parameters that reflect both disability level and compensatory mechanisms for all patients. This study investigated the clinical relevance of the global sagittal axis (GSA), a novel measure to evaluate the standing axis of the human body. METHODS: This is a retrospective review of patients who underwent full-body radiographs and completed health-related quality of life (HRQOL) questionnaires: Oswestry Disability Index (ODI), Scoliosis Research Society-22, EuroQol-5D (EQ-5D), and the visual analog scale for back and leg pain. The GSA was defined as the angle formed by a line from the midpoint of the femoral condyles to the center of C-7, and a line from the midpoint between the femoral condyles to the posterior superior corner of the S-1 sacral endplate. After evaluating the correlation of GSA/HRQOL with sagittal parameters, linear regression models were generated to investigate how ODI and GSA related to radiographic parameters (T-1 pelvic angle, pelvic retroversion, knee flexion, and pelvic posterior translation). RESULTS: One hundred forty-three patients (mean age 44 years) were included. The GSA correlated significantly with all HRQOL (up to r = 0.6 with EQ-5D) and radiographic parameters (up to r = 0.962 with sagittal vertical axis). Regression between ODI and sagittal radiographic parameters identified the GSA as an independent predictor (r = 0.517, r2 = 0.267; p < 0.001). Analysis of standardized coefficients revealed that when controlling for deformity, the GSA increased with a concurrent decrease in pelvic retroversion (-0.837) and increases in knee flexion (+0.287) and pelvic posterior translation (+0.193). CONCLUSIONS: The GSA is a simple, novel measure to assess the standing axis of the human body in the sagittal plane. The GSA correlated highly with spinopelvic and lower-extremities sagittal parameters and exhibited remarkable correlations with HRQOL, which exceeded other commonly used parameters.
AB - OBJECTIVE: Sagittal malalignment requires higher energy expenditure to maintain an erect posture. Because the clinical impact of sagittal alignment is affected by both the severity of the deformity and recruitment of compensatory mechanisms, it is important to investigate new parameters that reflect both disability level and compensatory mechanisms for all patients. This study investigated the clinical relevance of the global sagittal axis (GSA), a novel measure to evaluate the standing axis of the human body. METHODS: This is a retrospective review of patients who underwent full-body radiographs and completed health-related quality of life (HRQOL) questionnaires: Oswestry Disability Index (ODI), Scoliosis Research Society-22, EuroQol-5D (EQ-5D), and the visual analog scale for back and leg pain. The GSA was defined as the angle formed by a line from the midpoint of the femoral condyles to the center of C-7, and a line from the midpoint between the femoral condyles to the posterior superior corner of the S-1 sacral endplate. After evaluating the correlation of GSA/HRQOL with sagittal parameters, linear regression models were generated to investigate how ODI and GSA related to radiographic parameters (T-1 pelvic angle, pelvic retroversion, knee flexion, and pelvic posterior translation). RESULTS: One hundred forty-three patients (mean age 44 years) were included. The GSA correlated significantly with all HRQOL (up to r = 0.6 with EQ-5D) and radiographic parameters (up to r = 0.962 with sagittal vertical axis). Regression between ODI and sagittal radiographic parameters identified the GSA as an independent predictor (r = 0.517, r2 = 0.267; p < 0.001). Analysis of standardized coefficients revealed that when controlling for deformity, the GSA increased with a concurrent decrease in pelvic retroversion (-0.837) and increases in knee flexion (+0.287) and pelvic posterior translation (+0.193). CONCLUSIONS: The GSA is a simple, novel measure to assess the standing axis of the human body in the sagittal plane. The GSA correlated highly with spinopelvic and lower-extremities sagittal parameters and exhibited remarkable correlations with HRQOL, which exceeded other commonly used parameters.
KW - Deformity
KW - Full-body sagittal alignment
KW - GSA
KW - Global sagittal axis
UR - http://www.scopus.com/inward/record.url?scp=84990828238&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84990828238&partnerID=8YFLogxK
U2 - 10.3171/2016.2.SPINE151311
DO - 10.3171/2016.2.SPINE151311
M3 - Article
C2 - 27203811
AN - SCOPUS:84990828238
SN - 1547-5654
VL - 25
SP - 494
EP - 499
JO - Journal of Neurosurgery: Spine
JF - Journal of Neurosurgery: Spine
IS - 4
ER -