Case SeriesNormative Data of Pulmonary Function Tests and Radiographic Measures of Chest Development in Children Without Spinal Deformity: Is a T1–T12 Height of 22 cm Adequate?
Introduction
Management of early-onset scoliosis aims to improve and prevent deformity progression while accommodating and promoting growth of the spine and thoracic cavity. As early thoracic fusions in young patients whose lungs are immature and developing is associated with unacceptably poor functional results [1], [2], [3], [4], the old saying of a short, straight spine is better than a long, curved spine has been debunked. However, when to proceed with definitive fusion in patients with early-onset scoliosis continues to be an area of interesting debate and one without ultimate consensus.
Thoracic height measured between T1 and T12 is one radiographic marker used to guide timing of definitive fusion in this patient population, as it has been associated with pulmonary function tests (PFTs) [1], [5], [6]. In a landmark article by Karol et al., children who underwent early spinal fusions demonstrated compromised PFTs when thoracic height was <22 cm [1]. Although this threshold has been a benchmark, its association with appropriate long-term pulmonary function has recently been questioned [6]. As such, the goals of this study are twofold: (1) to develop normative data of PFTs and radiographic measures of chest development in normal children, and (2) to determine if the prior proposed T1–T12 height of 22 cm for spinal fusion in a growing child is adequate for pulmonary function based on normative PFT values at skeletal maturity.
Section snippets
Cohort
After approval from the Institutional Review Board, a tertiary-care children hospital's pulmonology database was queried to identify all children who underwent PFT evaluation. After including only children with PFT values >90% and without chest or spinal deformity, a radiology database was cross-referenced to identify all children who had a chest radiograph within two months of PFT studies. For each child, the following PFT and radiographic data were collected.
Pulmonary function data
- 1.
Absolute forced vital capacity
Cohorts
A total of 1,797 children were identified who underwent PFTs. Of this group, 149 children (average age 12.4 ± 3.0 years, range 7.1–18.4 years) met inclusion criteria. Demographic data are presented in Table 1. There were nearly twice as many girls (n = 97) as boys (n = 52). Number of girls by age group were as follows: <10 years (n = 25; average age 8.6 ± 0.8), 10–12 years (n = 16; average age 10.9 ± 0.5), 12–14 years (n = 17; average age 12.7 ± 0.5 years), and >14 years (n = 39; average age
Discussion
Shortening of the spine from T1–T12 is a concern with early thoracic fusion for spinal deformity, as it has a deleterious effect on the development of the pulmonary system [1], [2], [3], [4]. In this study, we present two major findings: 1) normative data of pulmonary function tests (PFTs) and radiographic measures of chest development in normal children and 2) a child whose T1–T12 height is halted and maintained at 22 cm to skeletal maturity is predicted to have FEV1 and FVC values <50% of
Conclusions
Percent-predicted FEV1 and FVC values for normal children with a T1–T12 height of 22 cm at skeletal maturity were <50%. Though this analysis does not take into consideration radial expansion of the chest or children with scoliosis (idiopathic, congenital, neuromuscular), these values are concerning and may not be adequate to guarantee that children with early-onset scoliosis who are fused with T1–T12 heights of 22 cm will have an asymptomatic pulmonary status in adulthood.
References (25)
- et al.
Continued deterioration in pulmonary function at minimum 18-year follow-up from early thoracic fusion in non-neuromuscular scoliosis
Spine Deform
(2017) - et al.
Reference values for paediatric pulmonary function testing: the Utrecht dataset
Respir Med
(2011) - et al.
The Veterans Administration-Army cooperative study of pulmonary function. I. Clinical spirometry in normal men
Am J Med
(1961) Long-term outcome of early fusions for congenital scoliosis
Spine Deform
(2018)- et al.
Pulmonary function following early thoracic fusion in non-neuromuscular scoliosis
J Bone Joint Surg Am
(2008) Early definitive spinal fusion in young children: what we have learned
Clin Orthop Relat Res
(2011)- et al.
A retrospective cohort study of pulmonary function, radiographic measures, and quality of life in children with congenital scoliosis: an evaluation of patient outcomes after early spinal fusion
Spine (Phila Pa 1976)
(2008) - et al.
Respiratory function and cosmesis at maturity in infantile-onset scoliosis
Spine (Phila Pa 1976)
(2003) - et al.
Is there a relationship between thoracic dimensions and pulmonary function in early-onset scoliosis?
Spine (Phila Pa 1976)
(2014) - et al.
Spine and thoracic height measurements have excellent interrater and intrarater reliability in patients with early onset scoliosis
Spine (Phila Pa 1976)
(2018)
Prediction of thoracic dimensions and spine length on the basis of individual pelvic dimensions: validation of the use of pelvic inlet width obtained by radiographs compared with computed tomography
Spine (Phila Pa 1976)
Reliability of radiographic measures for infantile idiopathic scoliosis
J Bone Joint Surg Am
Cited by (6)
3D quasi-automatic spine length assessment using low dose biplanar radiography after surgical correction in thoracic idiopathic scoliosis
2022, Medical Engineering and PhysicsCitation Excerpt :Indeed, decreasing thoracic height could result in restrictive lung dysfunction [28,29]. It would appear that a T1-T12 distance of 22 cm leads to asymptomatic lung status in adulthood [30]. Another application is severe scoliosis (Cobb angle is over 80°), where it may be useful to study the gain in height obtained by the halo preparation and to plan the operation date accordingly [31].
Long-Term Radiographic and Pulmonary Function Outcomes After Dual Growing-Rod Treatment for Severe Early-Onset Scoliosis
2023, Journal of Bone and Joint SurgeryOlder children with early onset scoliosis
2022, The Growing Spine: Management of Spinal Disorders in Young Children: Third EditionPulmonary evaluation in early-onset scoliosis
2022, The Growing Spine: Management of Spinal Disorders in Young Children: Third Edition
Author disclosures: AAT (none), JS (none), MK (none), JRG (none), SJL (none).
IRB approval: This study was approved by the Washington University School of Medicine Institutional Review Board (#201706176).
Funding Source: No funding.