TY - JOUR
T1 - Low radius of curvature growth-friendly rib-based implants increase the risk of developing clinically significant proximal junctional kyphosis
AU - Pediatric Spine Study Group
AU - Parker, Ellen
AU - Al Anazi, Mohammed
AU - Hurry, Jennifer K.
AU - Kawakami, Noriaki
AU - Cheung, Kenneth
AU - Kwan, Kenny
AU - Cheung, Jason
AU - Emans, John
AU - Karlin, Lawrence
AU - Snyder, Brian
AU - Miyanji, Firoz
AU - Gomez, Jaime
AU - Andras, Lindsay
AU - Skaggs, David
AU - Garg, Sumeet
AU - Roye, Benjamin
AU - Vitale, Michael
AU - Saiman, Lisa
AU - Cahill, Patrick
AU - Flynn, Jack
AU - Mayer, Oscar
AU - Oetgen, Matthew
AU - Murphy, Josh
AU - Sturm, Peter
AU - Parent, Stefan
AU - Sponseller, Paul
AU - Sawyer, Jeffrey
AU - Noelle, A. Larson
AU - Murphy, Robert
AU - Ying, G. Li
AU - Shah, Suken
AU - Anderson, Richard
AU - Blakemore, Laurel
AU - Brockmeyer, Douglas
AU - Smith, John
AU - Akbarnia, Behrooz
AU - Yaszay, Burt
AU - Glotzbecker, Michael
AU - Hardesty, Christina
AU - Thompson, George
AU - Redding, Gregory
AU - White, Klane
AU - Gupta, Purnendu
AU - Hwang, Steven
AU - Pahys, Josh
AU - Samdani, Amer
AU - Johnston, Charles
AU - McIntosh, Amy
AU - Sanders, James
AU - Schulz, Jacob
N1 - Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Scoliosis Research Society.
PY - 2023/5
Y1 - 2023/5
N2 - Background: Clinically significant proximal junctional kyphosis (PJK) occurs in 20% of children with scoliosis treated with posterior distraction-based growth-friendly surgery. In an effort to identify modifiable risk factors, it has been theorized biomechanically that low radius of curvature (ROC) implants (i.e., more curved rods) may increase post-operative thoracic kyphosis, and thus may pose a higher risk of developing PJK. We sought to test the hypothesis that early onset scoliosis (EOS) patients treated with low ROC distraction-based implants will have a greater risk of developing clinically significant PJK as compared to those treated with high ROC (straighter) implants. Methods: We conducted a retrospective review of prospectively collected data obtained from a multi-centre EOS database on children treated with rib-based distraction with a minimum 2-year follow-up. Variables of interest included: implant ROC at index (220 mm or 500 mm), participant age, pre-operative scoliosis, pre-operative kyphosis, and scoliosis etiology. PJK was defined as clinically significant if revision surgery with a superior extension of the upper instrumented vertebrae was performed. Results: In 148 participants with scoliosis, there was a higher risk of clinically significant PJK with low ROC (more curved) rods (OR: 2.6 (95% CI 1.09–5.99), χ2 (1, n = 148) = 4.8, p = 0.03). Participants had a mean pre-operative age of 5.3 years (4.6y 220 mm vs 6.2y 500 mm, p = 0.002). A logistic regression model was created with age as a confounding variable, but it was determined to be not significant (p = 0.6). Scoliosis etiologies included 52 neuromuscular, 52 congenital, 27 idiopathic, 17 syndromic with no significant differences in PJK risk between etiologies (p = 0.07). Overall, participants had pre-op scoliosis of 69° (67° 220 mm vs 72° 500 mm, p = 0.2), and kyphosis of 48° (45° 220 mm vs 51° 500 mm, p = 0.1). The change in thoracic kyphosis pre-operatively to final follow-up (mean 4.0 ± 0.2 years) was higher in participants treated with 220 mm implants compared to 500 mm implants (220 mm: 7.5 ± 2.6° vs 500 mm: − 4.0 ± 3.0°, p = 0.004). Conclusions: Use of low ROC (more curved) posterior distraction implants is associated with a significantly greater increase in thoracic kyphosis which likely led to a higher risk of developing clinically significant PJK in participants with EOS. Level of evidence: Level III – retrospective comparative study.
AB - Background: Clinically significant proximal junctional kyphosis (PJK) occurs in 20% of children with scoliosis treated with posterior distraction-based growth-friendly surgery. In an effort to identify modifiable risk factors, it has been theorized biomechanically that low radius of curvature (ROC) implants (i.e., more curved rods) may increase post-operative thoracic kyphosis, and thus may pose a higher risk of developing PJK. We sought to test the hypothesis that early onset scoliosis (EOS) patients treated with low ROC distraction-based implants will have a greater risk of developing clinically significant PJK as compared to those treated with high ROC (straighter) implants. Methods: We conducted a retrospective review of prospectively collected data obtained from a multi-centre EOS database on children treated with rib-based distraction with a minimum 2-year follow-up. Variables of interest included: implant ROC at index (220 mm or 500 mm), participant age, pre-operative scoliosis, pre-operative kyphosis, and scoliosis etiology. PJK was defined as clinically significant if revision surgery with a superior extension of the upper instrumented vertebrae was performed. Results: In 148 participants with scoliosis, there was a higher risk of clinically significant PJK with low ROC (more curved) rods (OR: 2.6 (95% CI 1.09–5.99), χ2 (1, n = 148) = 4.8, p = 0.03). Participants had a mean pre-operative age of 5.3 years (4.6y 220 mm vs 6.2y 500 mm, p = 0.002). A logistic regression model was created with age as a confounding variable, but it was determined to be not significant (p = 0.6). Scoliosis etiologies included 52 neuromuscular, 52 congenital, 27 idiopathic, 17 syndromic with no significant differences in PJK risk between etiologies (p = 0.07). Overall, participants had pre-op scoliosis of 69° (67° 220 mm vs 72° 500 mm, p = 0.2), and kyphosis of 48° (45° 220 mm vs 51° 500 mm, p = 0.1). The change in thoracic kyphosis pre-operatively to final follow-up (mean 4.0 ± 0.2 years) was higher in participants treated with 220 mm implants compared to 500 mm implants (220 mm: 7.5 ± 2.6° vs 500 mm: − 4.0 ± 3.0°, p = 0.004). Conclusions: Use of low ROC (more curved) posterior distraction implants is associated with a significantly greater increase in thoracic kyphosis which likely led to a higher risk of developing clinically significant PJK in participants with EOS. Level of evidence: Level III – retrospective comparative study.
KW - Early onset scoliosis (EOS)
KW - Proximal Junctional Kyphosis (PJK)
KW - Radius of curvature
KW - Rod shape
KW - Scoliosis
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U2 - 10.1007/s43390-023-00645-6
DO - 10.1007/s43390-023-00645-6
M3 - Article
C2 - 36689054
AN - SCOPUS:85146877920
SN - 2212-134X
VL - 11
SP - 733
EP - 738
JO - Spine deformity
JF - Spine deformity
IS - 3
ER -