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Paediatric lung disease
Effect of idiopathic thoracic scoliosis on the tracheobronchial tree
  1. James Farrell1 and
  2. Enrique Garrido2
  1. 1 School of Engineering, University of Edinburgh, Edinburgh, UK
  2. 2 Scottish National Spine Deformity Service, Royal Hospital for Sick Children, Edinburgh, UK
  1. Correspondence to Enrique Garrido; enrique.garrido{at}nhslothian.scot.nhs.uk

Abstract

Introduction High prevalence of obstructive lung disease has been reported in patients undergoing surgical correction of thoracic scoliosis. Airway narrowing due to spine morphology is analysed as a contributing factor.

Methods Preoperative surgical planning CTs of 34 patients with right-sided thoracic scoliosis (age: 17.6±9.0) were retrospectively analysed and compared with 15 non-scoliotic controls (age: 16.3±5.1). Three-dimensional models of spine and airway lumen were reconstructed. Based on thoracic sagittal profile, patients were divided into hypokyphosis (HypoS: <10°), normal kyphosis (NormS: ≥10° and <40°) and hyperkyphosis (HyperS: ≥40°) groups. Lumen area of bronchi, bifurcation angles and minimum spine–airway distance were measured. Pulmonary function tests were correlated to scoliosis, kyphosis and lumen area.

Results Loss of kyphosis led to proximity between bronchus intermedius (BI) and spine. HypoS (NormS) had lumen area reductions in the right main bronchus of 29% (19%), BI of 45% (23%), right middle lobar bronchus of 46% (32%) and right lower lobe bronchus (RLL7) of 66% (37%), respectively (P<0.05). The lower right superior segmental bronchus was reduced across all scoliotic groups (P<0.05). Airways were displaced caudal by 0.65±0.45 vertebra in patients with scoliosis. Loss of kyphosis correlated negatively with forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC), FVC/(FVC predicted) and FEV1/(FEV1 predicted) (P<0.01). Lumen area of trachea, right upper lobar bronchus, BI and RLL7 correlated negatively with FEV1/FVC. BI and RLL7 narrowing were strong predictors of FVC and FEV1 loss (P<0.001).

Conclusions Right-sided main stem airways are narrowed in HypoS and NormS. Loss of kyphosis leads to narrowing of BI and its trifurcation. FEV1/FVC correlated negatively with airway narrowing, implying an obstructive element to lung function impairment in patients with scoliosis and hypokyphosis.

  • paediatric lung disaese
  • lung physiology
  • paediatric physician
  • thoracic surgery

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/4.0/

https://doi.org/10.1136/bmjresp-2017-000264

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    Footnotes

    • Contributors JF and EG devised the study; JF performed the segmentation and measurements; EG conducted the literature review; JF and EG analysed and interpreted the results; JF prepared the figures; JF and EG drafted the manuscript and approved the final version.

    • Funding This study was supported in part by studentship funding from the Engineering and Physical Sciences Research Council (EPSRC) and K2M.

    • Competing interests None declared.

    • Patient consent Detail has been removed from this case description/these case descriptions to ensure anonymity. The editors and reviewers have seen the detailed information available and are satisfied that the information backs up the case the authors are making.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Data sharing statement No additional data are available.