Radiographic Predictors for Mechanical Failure After Adult Spinal Deformity Surgery: A Retrospective Cohort Study in 138 Patients

TY - JOUR

T1 - Radiographic Predictors for Mechanical Failure After Adult Spinal Deformity Surgery

T2 - A Retrospective Cohort Study in 138 Patients

AU - Hallager, Dennis W

AU - Karstensen, Sven

AU - Bukhari, Naeem

AU - Gehrchen, Martin

AU - Dahl, Benny

PY - 2017

Y1 - 2017

N2 - STUDY DESIGN: Retrospective cohort study at a single institution.OBJECTIVE: We aimed at estimating the rate of revision procedures and identify radiographic predictors of mechanical failure after adult spinal deformity surgery.SUMMARY OF BACKGROUND DATA: Mechanical failure rates after adult spinal deformity surgery range 12% to 37% in literature. Although the importance of spinal and spino-pelvic alignment is well documented for surgical outcome and ideal alignment has been proposed as sagittal vertical axis (SVA) < 5 cm, pelvic tilt < 20° and lumbar lordosis (LL) = pelvic incidence ± 9°, the role of radiographic sagittal spine parameters and alignment targets as predictors for mechanical failure remains uncertain.METHODS: A consecutive cohort of adult spinal deformity patients who underwent corrective surgery with at least 5 levels of instrumentation between January 2008 and December 2012 at a single tertiary spine unit were followed for at least 2 years. Time to death or failure was recorded and cause-specific Cox regressions were applied to evaluate predictors for mechanical failure or death.RESULTS: A total of 138 patients with median age of 61 years were included for analysis. Follow up ranged 2.1 to 6.8 years. In total 47% had revision and estimated failure rates were 16% at 1 year increasing to 56% at 5 years. A multivariate analysis adjusting for age at surgery showed increased hazard of failure from LL change > 30°, postoperative TK > 50°, and SS ≤30°. LL change was mostly because of 3-column osteotomy and ending the instrumentation at L5 or S1 increased the hazard of failure more than 6 fold compared with more cranial lumbar levels.CONCLUSION: Mechanical failure rate was 47% after adult spinal deformity corrective surgery. LL change > 30°, postoperative TK > 50°, and postoperative SS ≤30° were independent radiographic predictors associated with increased hazard of failure.LEVEL OF EVIDENCE: 4.

AB - STUDY DESIGN: Retrospective cohort study at a single institution.OBJECTIVE: We aimed at estimating the rate of revision procedures and identify radiographic predictors of mechanical failure after adult spinal deformity surgery.SUMMARY OF BACKGROUND DATA: Mechanical failure rates after adult spinal deformity surgery range 12% to 37% in literature. Although the importance of spinal and spino-pelvic alignment is well documented for surgical outcome and ideal alignment has been proposed as sagittal vertical axis (SVA) < 5 cm, pelvic tilt < 20° and lumbar lordosis (LL) = pelvic incidence ± 9°, the role of radiographic sagittal spine parameters and alignment targets as predictors for mechanical failure remains uncertain.METHODS: A consecutive cohort of adult spinal deformity patients who underwent corrective surgery with at least 5 levels of instrumentation between January 2008 and December 2012 at a single tertiary spine unit were followed for at least 2 years. Time to death or failure was recorded and cause-specific Cox regressions were applied to evaluate predictors for mechanical failure or death.RESULTS: A total of 138 patients with median age of 61 years were included for analysis. Follow up ranged 2.1 to 6.8 years. In total 47% had revision and estimated failure rates were 16% at 1 year increasing to 56% at 5 years. A multivariate analysis adjusting for age at surgery showed increased hazard of failure from LL change > 30°, postoperative TK > 50°, and SS ≤30°. LL change was mostly because of 3-column osteotomy and ending the instrumentation at L5 or S1 increased the hazard of failure more than 6 fold compared with more cranial lumbar levels.CONCLUSION: Mechanical failure rate was 47% after adult spinal deformity corrective surgery. LL change > 30°, postoperative TK > 50°, and postoperative SS ≤30° were independent radiographic predictors associated with increased hazard of failure.LEVEL OF EVIDENCE: 4.

KW - Adolescent

KW - Adult

KW - Aged

KW - Aged, 80 and over

KW - Body Weights and Measures

KW - Female

KW - Humans

KW - Male

KW - Middle Aged

KW - Osteotomy

KW - Reoperation

KW - Retrospective Studies

KW - Spinal Curvatures/diagnostic imaging

KW - Spinal Fusion

KW - Treatment Failure

KW - Young Adult

U2 - 10.1097/BRS.0000000000001996

DO - 10.1097/BRS.0000000000001996

M3 - Journal article

C2 - 27879571

SN - 0362-2436

VL - 42

SP - E855-E863

JO - Spine

JF - Spine

IS - 14

ER -