Low radius of curvature growth-friendly rib-based implants increase the risk of developing clinically significant proximal junctional kyphosis.
Spine Deform
; 11(3): 733-738, 2023 05.
Article
in En
| MEDLINE
| ID: mdl-36689054
ABSTRACT
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.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Scoliosis
/
Kyphosis
Type of study:
Etiology_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Child
/
Child, preschool
/
Humans
Language:
En
Journal:
Spine Deform
Year:
2023
Document type:
Article
Affiliation country:
Canadá