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Improvement of Pulmonary Function in Children With Early-Onset Scoliosis Using Magnetic Growth Rods

Yoon, Wai Weng MBBS, BSc (Hons), FRCS (Tr & Orth)*; Sedra, Fady MD*; Shah, Suken MRCS; Wallis, Colin MD; Muntoni, Francesco MD§; Noordeen, Hilali FRCS*

doi: 10.1097/BRS.0000000000000383
Deformity

Study Design. Case series.

Objective. To determine whether there is improvement in pulmonary function in children with early-onset scoliosis (EOS) using magnetic growth rods (MGRs).

Summary of Background Data. EOS deformities have large impacts on lung function and volumes. Deterioration of pulmonary function in scoliosis is multifactorial, including severity, location of apex vertebra, and medical comorbidities. MGR insertion has benefits including reduction in operative procedures with repeated anesthetics, cost-effectiveness, and minimizing surgical and psychological distress. Pulmonary function tests provide objective and quantitative information about functional impairment caused by scoliosis. This is the first study that observes the MGR lengthening and changes in pulmonary function during a minimum period of 2.2 years.

Methods. Six cases of EOS secondary to neuromuscular disease were identified. Mean age at diagnosis was 2.8 year (2.1–4.9 yr), mean age at surgery was 7.5 year (5–10 yr), and mean follow-up was 2.5 year (2.2–2.8 yr). Pulmonary function test (forced vital capacity [FVC] + forced expired volume in 1 second [FEV1] both % predicted) was measured before and after insertion of MGR and at every lengthening clinic subsequently for a minimum 2 years. Coronal and sagittal Cobb angles were measured pre- and postoperatively as were length extension of growth rods. All except 1 patient had dual MGRs inserted (the other had a single rod). Lengthening was commenced and data was collected at 6-month intervals.

Results. Average correction was 34° ± 18° and 36° ± 15° for coronal and sagittal Cobb angles, respectively. Mean lengthening achieved was 24.9 mm. Mean improvement in postoperative FVC and FEV1 was 14.1% and 17.2%, respectively. There was significant difference between the median preoperative and postoperative Cobb angle, P = 0.028.

Conclusion. This study demonstrates early intervention using MGR in patients with EOS is associated with significant improvement in postoperative pulmonary function tests; and significant improvement in deformity correction with use of MGR with added benefits of reduction in repeat anesthesia, reduction in surgical and psychological distress, and cost-effectiveness.

Level of Evidence: 4

Magnetic growth rod (MGR) intervention in patients with early-onset scoliosis is associated with a significant improvement in postoperative pulmonary function tests. We also found significant improvement in deformity correction with use of MGR with added benefits of reduction in repeat anesthesia, reduction in surgical and psychological distress, as well as cost-effectiveness.

*Spinal Deformity Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom

Spine and Scoliosis Center, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE

Respiratory Paediatric Department, Great Ormond Street Hospital, London, United Kingdom; and

§Dubowitz Neuromuscular Centre, Great Ormond Street Hospital, London, United Kingdom.

Address correspondence and reprint requests to Wai Weng Yoon, MBBS, BSc (Hons), FRCS (Tr & Orth), Spinal Deformity Unit, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, United Kingdom; E-mail: wwyoon@me.com

Acknowledgment date: May 14, 2013. First revision date: September 6, 2013. Second revision date: January 23, 2014. Third revision date: January 27, 2014. Acceptance date: January 28, 2014.

The device(s)/drug(s) that is/are the subject of this manuscript is/are not FDA-approved for this indication and is/are not commercially available in the United States.

The manuscript includes unlabeled/investigational uses of the products/devices listed below and the status of these is disclosed in the manuscript: Magec Rod.

National Health Service, United Kingdom, funds were received to support this work. H.N. received funding related to the study for consulting fee or honorarium, support for travel and fees for participation in review activities. W.W.Y. received funding related to the study for support for travel.

Relevant financial activities outside the submitted work: board membership, consultancy, employment, expert testimony, grants/grants pending, payment for lectures, patents, royalties, payment for development of educational presentations, travel/accommodations/meeting expenses, and stock/stock options.

© 2014 by Lippincott Williams & Wilkins