Additional Risk Factors for Adding-On After Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis

Implication of Lowest Instrumented Vertebra Angle and Lumbosacral Takeoff

Woojin Cho, Michael J. Faloon, David Essig, Gbolabo Sokunbi, Thomas Ross, Matthew Cunningham, Oheneba Boachie-Adjei

Research output: Contribution to journalArticle

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Abstract

Study Design: Retrospective chart and radiographic review. Objective: The purpose of this study was to identify any additional risk factors adding-on after selective thoracic fusion in adolescent idiopathic scoliosis (AIS). Summary of Background Data: Previous studies have shown that the proper selection of lowest instrumented vertebra (LIV) is critical in preventing adding-on (AD) phenomenon after selective thoracic fusion (STF). However, even after selecting the correct LIV, AD can still occur. Methods: This is a retrospective review of 380 consecutive AIS patients who underwent corrective surgery by a single surgeon. LIV was chosen as stable vertebra (SV) or SV-1 if intersected by the center sacral vertical line (CSVL). One hundred thirty-five patients were identified who had complete radiographic images stored in PACS. After Lenke 5, anterior or combined surgeries, TL fusion, and hybrid construct were excluded, two groups were identified out of 78 patients who received STF with all pedicle screw construct: Adding-on (AD) and Control. AD was defined as >5° angle of the superior endplate of LIV-1 to the inferior endplate of LIV+1 between postoperation and the final follow-up. We analyzed the values for the AD group and compared them with those for the control group to identify risk factors not previously defined. Results: Patients with other complication and follow-up less than 2 years were excluded, and there remained 11 patients in AD (14%), and 8 in the control group. There was no significant difference between the 2 groups in terms of demographic data, LIV selection, and curve types. In AD, there was significant curve progression within fused segments. Even though lumbosacral takeoff (LSTO) was not significantly different, (LIV-H)+LSTO and LIV-H (LIV horizontal) showed significant difference. Conclusion: After excluding the effect of known risk factors for AD, LIV-H angle, and LIV-H mismatch with LSTO were found to be the additional risk factors for AD. In addition to consideration of other risk factors such as LIV selection or Risser stage, these risk factors should be considered.

Original languageEnglish (US)
JournalSpine Deformity
DOIs
StateAccepted/In press - 2017

Fingerprint

Scoliosis
Spine
Thorax
Control Groups
Retrospective Studies
Demography

Keywords

  • Adding-on
  • Adolescent idiopathic scoliosis (AIS)
  • Lowest instrumented vertebrae (LIV)
  • Lumbosacral takeoff (LSTO)

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

Cite this

Additional Risk Factors for Adding-On After Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis : Implication of Lowest Instrumented Vertebra Angle and Lumbosacral Takeoff. / Cho, Woojin; Faloon, Michael J.; Essig, David; Sokunbi, Gbolabo; Ross, Thomas; Cunningham, Matthew; Boachie-Adjei, Oheneba.

In: Spine Deformity, 2017.

Research output: Contribution to journalArticle

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title = "Additional Risk Factors for Adding-On After Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis: Implication of Lowest Instrumented Vertebra Angle and Lumbosacral Takeoff",
abstract = "Study Design: Retrospective chart and radiographic review. Objective: The purpose of this study was to identify any additional risk factors adding-on after selective thoracic fusion in adolescent idiopathic scoliosis (AIS). Summary of Background Data: Previous studies have shown that the proper selection of lowest instrumented vertebra (LIV) is critical in preventing adding-on (AD) phenomenon after selective thoracic fusion (STF). However, even after selecting the correct LIV, AD can still occur. Methods: This is a retrospective review of 380 consecutive AIS patients who underwent corrective surgery by a single surgeon. LIV was chosen as stable vertebra (SV) or SV-1 if intersected by the center sacral vertical line (CSVL). One hundred thirty-five patients were identified who had complete radiographic images stored in PACS. After Lenke 5, anterior or combined surgeries, TL fusion, and hybrid construct were excluded, two groups were identified out of 78 patients who received STF with all pedicle screw construct: Adding-on (AD) and Control. AD was defined as >5° angle of the superior endplate of LIV-1 to the inferior endplate of LIV+1 between postoperation and the final follow-up. We analyzed the values for the AD group and compared them with those for the control group to identify risk factors not previously defined. Results: Patients with other complication and follow-up less than 2 years were excluded, and there remained 11 patients in AD (14{\%}), and 8 in the control group. There was no significant difference between the 2 groups in terms of demographic data, LIV selection, and curve types. In AD, there was significant curve progression within fused segments. Even though lumbosacral takeoff (LSTO) was not significantly different, (LIV-H)+LSTO and LIV-H (LIV horizontal) showed significant difference. Conclusion: After excluding the effect of known risk factors for AD, LIV-H angle, and LIV-H mismatch with LSTO were found to be the additional risk factors for AD. In addition to consideration of other risk factors such as LIV selection or Risser stage, these risk factors should be considered.",
keywords = "Adding-on, Adolescent idiopathic scoliosis (AIS), Lowest instrumented vertebrae (LIV), Lumbosacral takeoff (LSTO)",
author = "Woojin Cho and Faloon, {Michael J.} and David Essig and Gbolabo Sokunbi and Thomas Ross and Matthew Cunningham and Oheneba Boachie-Adjei",
year = "2017",
doi = "10.1016/j.jspd.2017.08.008",
language = "English (US)",
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T1 - Additional Risk Factors for Adding-On After Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis

T2 - Implication of Lowest Instrumented Vertebra Angle and Lumbosacral Takeoff

AU - Cho, Woojin

AU - Faloon, Michael J.

AU - Essig, David

AU - Sokunbi, Gbolabo

AU - Ross, Thomas

AU - Cunningham, Matthew

AU - Boachie-Adjei, Oheneba

PY - 2017

Y1 - 2017

N2 - Study Design: Retrospective chart and radiographic review. Objective: The purpose of this study was to identify any additional risk factors adding-on after selective thoracic fusion in adolescent idiopathic scoliosis (AIS). Summary of Background Data: Previous studies have shown that the proper selection of lowest instrumented vertebra (LIV) is critical in preventing adding-on (AD) phenomenon after selective thoracic fusion (STF). However, even after selecting the correct LIV, AD can still occur. Methods: This is a retrospective review of 380 consecutive AIS patients who underwent corrective surgery by a single surgeon. LIV was chosen as stable vertebra (SV) or SV-1 if intersected by the center sacral vertical line (CSVL). One hundred thirty-five patients were identified who had complete radiographic images stored in PACS. After Lenke 5, anterior or combined surgeries, TL fusion, and hybrid construct were excluded, two groups were identified out of 78 patients who received STF with all pedicle screw construct: Adding-on (AD) and Control. AD was defined as >5° angle of the superior endplate of LIV-1 to the inferior endplate of LIV+1 between postoperation and the final follow-up. We analyzed the values for the AD group and compared them with those for the control group to identify risk factors not previously defined. Results: Patients with other complication and follow-up less than 2 years were excluded, and there remained 11 patients in AD (14%), and 8 in the control group. There was no significant difference between the 2 groups in terms of demographic data, LIV selection, and curve types. In AD, there was significant curve progression within fused segments. Even though lumbosacral takeoff (LSTO) was not significantly different, (LIV-H)+LSTO and LIV-H (LIV horizontal) showed significant difference. Conclusion: After excluding the effect of known risk factors for AD, LIV-H angle, and LIV-H mismatch with LSTO were found to be the additional risk factors for AD. In addition to consideration of other risk factors such as LIV selection or Risser stage, these risk factors should be considered.

AB - Study Design: Retrospective chart and radiographic review. Objective: The purpose of this study was to identify any additional risk factors adding-on after selective thoracic fusion in adolescent idiopathic scoliosis (AIS). Summary of Background Data: Previous studies have shown that the proper selection of lowest instrumented vertebra (LIV) is critical in preventing adding-on (AD) phenomenon after selective thoracic fusion (STF). However, even after selecting the correct LIV, AD can still occur. Methods: This is a retrospective review of 380 consecutive AIS patients who underwent corrective surgery by a single surgeon. LIV was chosen as stable vertebra (SV) or SV-1 if intersected by the center sacral vertical line (CSVL). One hundred thirty-five patients were identified who had complete radiographic images stored in PACS. After Lenke 5, anterior or combined surgeries, TL fusion, and hybrid construct were excluded, two groups were identified out of 78 patients who received STF with all pedicle screw construct: Adding-on (AD) and Control. AD was defined as >5° angle of the superior endplate of LIV-1 to the inferior endplate of LIV+1 between postoperation and the final follow-up. We analyzed the values for the AD group and compared them with those for the control group to identify risk factors not previously defined. Results: Patients with other complication and follow-up less than 2 years were excluded, and there remained 11 patients in AD (14%), and 8 in the control group. There was no significant difference between the 2 groups in terms of demographic data, LIV selection, and curve types. In AD, there was significant curve progression within fused segments. Even though lumbosacral takeoff (LSTO) was not significantly different, (LIV-H)+LSTO and LIV-H (LIV horizontal) showed significant difference. Conclusion: After excluding the effect of known risk factors for AD, LIV-H angle, and LIV-H mismatch with LSTO were found to be the additional risk factors for AD. In addition to consideration of other risk factors such as LIV selection or Risser stage, these risk factors should be considered.

KW - Adding-on

KW - Adolescent idiopathic scoliosis (AIS)

KW - Lowest instrumented vertebrae (LIV)

KW - Lumbosacral takeoff (LSTO)

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