Jeffrey Hills,Gregory M Mundis,Eric O Klineberg,Justin S Smith,Breton Line,Jeffrey L Gum,Themistocles S Protopsaltis,D Kojo Hamilton,Alex Soroceanu,Robert Eastlack,Pierce Nunley,Khaled M Kebaish,Lawrence G Lenke,Richard A Hostin,Munish C Gupta,Han Jo Kim,Christopher P Ames,Douglas C Burton,Christopher I Shaffrey,Frank J Schwab,Virginie Lafage,Renaud Lafage,Shay Bess,Michael P Kelly,
{"title":"T4-L1-髋轴:长结构成人脊柱畸形手术中的矢状脊柱重新对位目标:早期影响。","authors":"Jeffrey Hills,Gregory M Mundis,Eric O Klineberg,Justin S Smith,Breton Line,Jeffrey L Gum,Themistocles S Protopsaltis,D Kojo Hamilton,Alex Soroceanu,Robert Eastlack,Pierce Nunley,Khaled M Kebaish,Lawrence G Lenke,Richard A Hostin,Munish C Gupta,Han Jo Kim,Christopher P Ames,Douglas C Burton,Christopher I Shaffrey,Frank J Schwab,Virginie Lafage,Renaud Lafage,Shay Bess,Michael P Kelly,","doi":"10.2106/jbjs.23.00372","DOIUrl":null,"url":null,"abstract":"BACKGROUND\r\nOur understanding of the relationship between sagittal alignment and mechanical complications is evolving. In normal spines, the L1-pelvic angle (L1PA) accounts for the magnitude and distribution of lordosis and is strongly associated with pelvic incidence (PI), and the T4-pelvic angle (T4PA) is within 4° of the L1PA. We aimed to examine the clinical implications of realignment to a normal L1PA and T4-L1PA mismatch.\r\n\r\nMETHODS\r\nA prospective multicenter adult spinal deformity registry was queried for patients who underwent fixation from the T1-T5 region to the sacrum and had 2-year radiographic follow-up. Normal sagittal alignment was defined as previously described for normal spines: L1PA = PI × 0.5 - 21°, and T4-L1PA mismatch = 0°. Mechanical failure was defined as severe proximal junctional kyphosis (PJK), displaced rod fracture, or reoperation for junctional failure, pseudarthrosis, or rod fracture within 2 years. Multivariable nonlinear logistic regression was used to define target ranges for L1PA and T4-L1PA mismatch that minimized the risk of mechanical failure. The relationship between changes in T4PA and changes in global sagittal alignment according to the C2-pelvic angle (C2PA) was determined using linear regression. Lastly, multivariable regression was used to assess associations between initial postoperative C2PA and patient-reported outcomes at 1 year, adjusting for preoperative scores and age.\r\n\r\nRESULTS\r\nThe median age of the 247 included patients was 64 years (interquartile range, 57 to 69 years), and 202 (82%) were female. Deviation from a normal L1PA or T4-L1PA mismatch in either direction was associated with a significantly higher risk of mechanical failure, independent of age. Risk was minimized with an L1PA of PI × 0.5 - (19° ± 2°) and T4-L1PA mismatch between -3° and +1°. Changes in T4PA and in C2PA at the time of final follow-up were strongly associated (r2 = 0.96). Higher postoperative C2PA was independently associated with more disability, more pain, and worse self-image at 1 year.\r\n\r\nCONCLUSIONS\r\nWe defined sagittal alignment targets using L1PA (relative to PI) and the T4-L1PA mismatch, which are both directly modifiable during surgery. In patients undergoing long fusion to the sacrum, realignment based on these targets may lead to fewer mechanical failures.\r\n\r\nLEVEL OF EVIDENCE\r\nTherapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.","PeriodicalId":22625,"journal":{"name":"The Journal of Bone & Joint Surgery","volume":"64 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The T4-L1-Hip Axis: Sagittal Spinal Realignment Targets in Long-Construct Adult Spinal Deformity Surgery: Early Impact.\",\"authors\":\"Jeffrey Hills,Gregory M Mundis,Eric O Klineberg,Justin S Smith,Breton Line,Jeffrey L Gum,Themistocles S Protopsaltis,D Kojo Hamilton,Alex Soroceanu,Robert Eastlack,Pierce Nunley,Khaled M Kebaish,Lawrence G Lenke,Richard A Hostin,Munish C Gupta,Han Jo Kim,Christopher P Ames,Douglas C Burton,Christopher I Shaffrey,Frank J Schwab,Virginie Lafage,Renaud Lafage,Shay Bess,Michael P Kelly,\",\"doi\":\"10.2106/jbjs.23.00372\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"BACKGROUND\\r\\nOur understanding of the relationship between sagittal alignment and mechanical complications is evolving. In normal spines, the L1-pelvic angle (L1PA) accounts for the magnitude and distribution of lordosis and is strongly associated with pelvic incidence (PI), and the T4-pelvic angle (T4PA) is within 4° of the L1PA. We aimed to examine the clinical implications of realignment to a normal L1PA and T4-L1PA mismatch.\\r\\n\\r\\nMETHODS\\r\\nA prospective multicenter adult spinal deformity registry was queried for patients who underwent fixation from the T1-T5 region to the sacrum and had 2-year radiographic follow-up. Normal sagittal alignment was defined as previously described for normal spines: L1PA = PI × 0.5 - 21°, and T4-L1PA mismatch = 0°. Mechanical failure was defined as severe proximal junctional kyphosis (PJK), displaced rod fracture, or reoperation for junctional failure, pseudarthrosis, or rod fracture within 2 years. Multivariable nonlinear logistic regression was used to define target ranges for L1PA and T4-L1PA mismatch that minimized the risk of mechanical failure. The relationship between changes in T4PA and changes in global sagittal alignment according to the C2-pelvic angle (C2PA) was determined using linear regression. Lastly, multivariable regression was used to assess associations between initial postoperative C2PA and patient-reported outcomes at 1 year, adjusting for preoperative scores and age.\\r\\n\\r\\nRESULTS\\r\\nThe median age of the 247 included patients was 64 years (interquartile range, 57 to 69 years), and 202 (82%) were female. Deviation from a normal L1PA or T4-L1PA mismatch in either direction was associated with a significantly higher risk of mechanical failure, independent of age. Risk was minimized with an L1PA of PI × 0.5 - (19° ± 2°) and T4-L1PA mismatch between -3° and +1°. Changes in T4PA and in C2PA at the time of final follow-up were strongly associated (r2 = 0.96). Higher postoperative C2PA was independently associated with more disability, more pain, and worse self-image at 1 year.\\r\\n\\r\\nCONCLUSIONS\\r\\nWe defined sagittal alignment targets using L1PA (relative to PI) and the T4-L1PA mismatch, which are both directly modifiable during surgery. In patients undergoing long fusion to the sacrum, realignment based on these targets may lead to fewer mechanical failures.\\r\\n\\r\\nLEVEL OF EVIDENCE\\r\\nTherapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.\",\"PeriodicalId\":22625,\"journal\":{\"name\":\"The Journal of Bone & Joint Surgery\",\"volume\":\"64 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-09-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"The Journal of Bone & Joint Surgery\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.2106/jbjs.23.00372\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Journal of Bone & Joint Surgery","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.2106/jbjs.23.00372","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
The T4-L1-Hip Axis: Sagittal Spinal Realignment Targets in Long-Construct Adult Spinal Deformity Surgery: Early Impact.
BACKGROUND
Our understanding of the relationship between sagittal alignment and mechanical complications is evolving. In normal spines, the L1-pelvic angle (L1PA) accounts for the magnitude and distribution of lordosis and is strongly associated with pelvic incidence (PI), and the T4-pelvic angle (T4PA) is within 4° of the L1PA. We aimed to examine the clinical implications of realignment to a normal L1PA and T4-L1PA mismatch.
METHODS
A prospective multicenter adult spinal deformity registry was queried for patients who underwent fixation from the T1-T5 region to the sacrum and had 2-year radiographic follow-up. Normal sagittal alignment was defined as previously described for normal spines: L1PA = PI × 0.5 - 21°, and T4-L1PA mismatch = 0°. Mechanical failure was defined as severe proximal junctional kyphosis (PJK), displaced rod fracture, or reoperation for junctional failure, pseudarthrosis, or rod fracture within 2 years. Multivariable nonlinear logistic regression was used to define target ranges for L1PA and T4-L1PA mismatch that minimized the risk of mechanical failure. The relationship between changes in T4PA and changes in global sagittal alignment according to the C2-pelvic angle (C2PA) was determined using linear regression. Lastly, multivariable regression was used to assess associations between initial postoperative C2PA and patient-reported outcomes at 1 year, adjusting for preoperative scores and age.
RESULTS
The median age of the 247 included patients was 64 years (interquartile range, 57 to 69 years), and 202 (82%) were female. Deviation from a normal L1PA or T4-L1PA mismatch in either direction was associated with a significantly higher risk of mechanical failure, independent of age. Risk was minimized with an L1PA of PI × 0.5 - (19° ± 2°) and T4-L1PA mismatch between -3° and +1°. Changes in T4PA and in C2PA at the time of final follow-up were strongly associated (r2 = 0.96). Higher postoperative C2PA was independently associated with more disability, more pain, and worse self-image at 1 year.
CONCLUSIONS
We defined sagittal alignment targets using L1PA (relative to PI) and the T4-L1PA mismatch, which are both directly modifiable during surgery. In patients undergoing long fusion to the sacrum, realignment based on these targets may lead to fewer mechanical failures.
LEVEL OF EVIDENCE
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.