Differences in spine growth potential for Sanders maturation stages 7A and 7B have implications for treatment of idiopathic scoliosis.

PURPOSE: This study aimed to clarify the differences in spine and total body height growth and curve progression between Sanders maturation stage (SMS) 7A and 7B in patients with adolescent idiopathic scoliosis (AIS). METHODS: This retrospective case-control study involving patients with AIS at SMS 7 evaluated the differential gains in the spine (T1-S1) and total body height and curve progression between SMS 7A and 7B. A validated formula was used to calculate the corrected height, accounting for height loss due to scoliosis. A multivariable non-linear and logistic regression model was applied to assess the distinct growth and curve progression patterns between the SMS 7 subtypes, adjusting for potential confounders. RESULTS: A total of 231 AIS patients (83% girls, mean age 13.9 ± 1.2 years) were included, with follow-up averaging 3.0 years. Patients at SMS 7A exhibited larger gains in spine height (9.9 mm vs. 6.3 mm) and total body height (19.8 mm vs. 13.4 mm) compared with SMS 7B. These findings remained consistent even after adjustments for curve magnitude. Non-linear regression models showed continued spine and total body height increases plateauing after 2 years, significantly greater in SMS 7A. More SMS 7A patients had curve progression over 10°, with an adjusted odds ratio of 3.31. CONCLUSION: This study revealed that patients staged SMS 7A exhibited more spine and total body growth and a greater incidence of substantial curve progression than those at 7B. These findings imply that delaying brace discontinuation until reaching 7B could be beneficial, particularly for those with larger curves. LEVEL OF EVIDENCE: Level III (Case-control study).

Walking status and spinopelvic parameters in young children with achondroplasia: 10-year follow-up.

PURPOSE: Thoracolumbar kyphosis (TLK) is common in children with achondroplasia and resolves in 90% by 10 years of age. Our purpose was to describe the natural progression of TLK in a cohort of pre-walking children with achondroplasia. METHODS: A single-center, retrospective review identified 62 children (32 male, 30 female) with achondroplasia. Clinical information and sagittal spinopelvic parameters were collected. The children were divided into positive pelvic tilt (PT) and negative PT. All parents were routinely counseled about unsupported sitting. RESULTS: Spontaneous resolution rate was 64.5% at 1-year post-walking, 74.2% at 5 years of age, and 88.7% at 10 years of age. None of the children required posterior spinal decompression and fusion for progressive deformity or symptomatic spinal stenosis. At 1-year post-walking, the negative PT group had a higher sacral slope (p = 0.006), higher lumbar lordosis (p < 0.001), and lower pelvic incidence (p < 0.001). This relationship remained constant up to 10 years of age, and there was no association with TLK. CONCLUSION: In this largest series to date, spontaneous resolution of TLK in children with achondroplasia was 64.5% at 1-year post-walking, 74.2% at 5 years of age, and 88.7% in children followed to 10 years of age. With early identification and regular follow-up with patient education, no patient in this series required treatment or developed symptomatic spinal stenosis. While not predictive of resolution of TLK, the dichotomous presentation of PT in young children with achondroplasia persists at 5 and 10 years of age and reliably predicts the spinopelvic parameters. LEVEL OF EVIDENCE: III-retrospective comparative study.