Faculty Collaboration Database

Radiographic and Respiratory Effects of Growing Rods in Children With Spinal Muscular Atrophy. J Pediatr Orthop 2017 Dec;37(8):e500-e504

Date

09/17/2016

Pubmed ID

27636914

Pubmed Central ID

PMC5352553

DOI

10.1097/BPO.0000000000000867

Scopus ID

2-s2.0-84987866690 (requires institutional sign-in at Scopus site)   30 Citations

Abstract

BACKGROUND: Respiratory weakness and spinal deformity are common in patients with spinal muscular atrophy (SMA). Posterior (distraction type) growing rods have recently gained favor as a treatment option in this population, due to their ability to prevent spinal deformity progression and their potential to allow lung volumes to increase over time. The objective of this study was to determine the impact of posterior growing rods on the spinal alignment and respiratory function in children with SMA with intermediate term follow-up.

METHODS: A single center, retrospective review was performed on SMA patients treated with growing rods, inserted between 2004 and 2010, with a minimum of 2-year follow-up. SMA type, changes in the route of bi-level positive airway pressure respiratory support and the amount of time receiving respiratory support are reported. Pulmonary function tests (PFTs) and radiographs were reviewed and data evaluated preinsertion, postinsertion, and at latest follow-up.

RESULTS: Sixteen children with SMA (5 type I, 11 type II) met inclusion criteria. The average age of insertion was 5.8 (±1.5) years, the median number of lengthenings was 4 (range, 3 to 5), and the median time between insertion and last clinical review was 4.7 (range, 2.7 to 9.5) years. Radiographic review demonstrated significant (P<0.05) improvements in the following: Spinal curve magnitude, pelvic obliquity, space available for the lung, rib vertebral angle difference, and thoracic kyphosis following growing rod implantation. Thoracic and lumbar height and chest width and depth increased significantly (P<0.05) over the lengthening process. None of the patients initially required more than noninvasive positive pressure ventilation support. Fifteen of the 16 experienced no changes in their noninvasive positive pressure ventilation support needs throughout the study duration, requiring support only at night and naps. Serial PFTs were available for 6 children with SMA type II. PFTs demonstrated significant improvements in absolute forced vital capacity (FVC), minimal changes in the maximal inspiratory and expiratory pressures, and a gradual worsening of percent predicted FVC.

CONCLUSIONS: Clinical respiratory support requirements appear to stabilize following the insertion and lengthening of posterior based growing rods in the SMA population. Similar to previous studies, increased spinal height and thoracic cavity size were noted throughout the process. Despite an increasing absolute FVC, the percent predicted FVC diminished over time.

LEVEL OF EVIDENCE: Level IV-therapeutic.

Author List

Lenhart RL, Youlo S, Schroth MK, Noonan KJ, McCarthy J, Mann D, Hetzel S, Sund SA, Halanski MA

Author

Rachel L. Lenhart MD Assistant Professor in the Orthopaedic Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Child
Child, Preschool
Disease Progression
Female
Humans
Kyphosis
Lung
Male
Muscular Atrophy, Spinal
Orthotic Devices
Radiography
Retrospective Studies
Scoliosis
Treatment Outcome
Vital Capacity