Short term effect and effect on rate of lung function decline
after surgery for neuromuscular or syndromic scoliosis.
Esther S. Veldhoen, MRCPCH 1, Anneloes de Vries,
Msc1 , Tom P.C. Schlosser, PhD2,
Moyo C. Kruyt, PhD2 , Ruben P.A. van Eijk,
PhD3,4, Joyce M. Tersmette, Msc5,
Erik H. Hulzebos, PhD6, Ludo W. van der Pol,
PhD3, Roelie M. Wösten-van Asperen,
PhD1 , Cornelis K. van der Ent,
PhD5.
1 Pediatric Intensive Care Unit, Wilhelmina Children’s
Hospital, University Medical Center Utrecht,The Netherlands.
2Department of Orthopedic surgery, University Medical
Center Utrecht,The Netherlands.
3 Department of Neurology, Brain Centre Rudolf Magnus,
University Medical Center Utrecht, The Netherlands.
4Biostatistics & Research Support, Julius Center for
Health Sciences and Primary Care, University Medical Center Utrecht,
Utrecht University, Utrecht, The Netherlands
5Department of Pediatric Pulmonology, Wilhelmina
Children’s Hospital, University Medical Center Utrecht, The Netherlands.
6Child Development and Exercise Center, Wilhelmina
Children’s Hospital, University Medical Center Utrecht, The Netherlands.
Corresponding Author: E.S. Veldhoen Wilhelmina Children’s Hospital,
University Medical Center Utrecht, PO box 85090, 3508 AB Utrecht The
Netherlands Tel +31 887554702
E.S.Veldhoen@umcutrecht.nl
No financial support or grants.
Keywords: Lung function; Neuromuscular disease; Scoliosis,
Abbreviated title: Lung function after scoliosis surgery.
Abstract
Introduction
Understanding the impact of scoliosis surgery on lung function is
important for counseling patients about risks and benefits of surgery.
We prospectively compared the trends in lung function test (LFT) results
prior to and after scoliosis surgery in children with neuromuscular
diseases, or dysmorphic syndromes. We hypothesized a stabilization.
Methods
We prospectively included children with neuromuscular or syndromic
scoliosis able to perform LFTs. We studied (Forced) Vital Capacity
((F)VC), the ratio of Forced Expiratory Volume in 1 second
(FEV1) and FVC, and Peak Expiratory Flow (PEF).
Preoperative LFT results were compared with results 3-4 months after
surgery. The mean monthly change in LFT results up to 2 years after
surgery was compared with the preoperative natural history using linear
mixed effects models.
Results
We included 43 patients. No significant change was observed in absolute
values of (F)VC, FEV1/FVC and PEF prior to and after
surgery. Median standardized VC, FVC and PEF decreased significantly
after surgery from 59 to 58%, 60 to 51% and 61 to 53% respectively.
The monthly rate of change in FVC was -0.13 % (95% CI -0.42 to 0.17)
prior to surgery and -0.20% (95% CI -0.42 to 0.03) after surgery, mean
difference -0.07 (95% CI -0.46 to 0.31; p=0.36).
Conclusion
No stabilization of lung function 3-4 months after scoliosis surgery was
observed in children with neuromuscular and syndromic scoliosis with
restrictive lung function disease. The effect of surgery on the rate of
lung function decline remains inconclusive.
Introduction
Scoliosis is a common complication in patients with neuromuscular
diseases (NMDs) and genetic syndromes and scoliosis surgery may be
necessary for a number of reasons. It improves ease of nursing care,
reduces back pain and allows the patient a much better sitting posture
and balance, thereby improving the patient’s overall quality of life and
self-image 1,2.
One of the more significant factors causing morbidity and mortality in
patients with neuromuscular scoliosis is the deterioration in pulmonary
function to which scoliosis progression may contribute1. By distorting thoracic anatomy and rib alignment,
severe scoliosis decreases the compliance of the chest wall, thereby
restricting vital capacity (VC) 2, while lordotic
deformation of the thoracic spine may cause bronchial kinking or
compression and bronchial obstruction 3. Straightening
the spine has the potential to improve the ability to elevate the ribs
and thus expand the chest on inspiration 2. On the
other hand, children with preexisting respiratory compromise have an
increased risk of developing postoperative complications4. Understanding the impact of neuromuscular or
syndromic scoliosis surgery on lung function is important for counseling
patients about risks and longer term benefits of scoliosis surgery on
respiratory function 2.
Research on the impact of scoliosis surgery on lung function has yielded
conflicting results.
In this prospective cohort study, we compared lung function test (LFT)
results of children with probable restrictive lung function due to
neuromuscular disease (NMD) or syndromic syndromes prior to and after
scoliosis surgery in a single center.
We aimed to study the short term improvement of lung function after
surgery and determine the mean change in post-operative compared to
pre-operative progression rate in lung function. We hypothesized that
scoliosis surgery slows the rate of lung function decline.
Materials and methods
Eligibility was checked in pediatric patients planned for surgery for a
neuromuscular or syndromic scoliosis at the preoperative clinic of the
Pediatric Intensive Care Unit (PICU) of the Wilhelmina Children’s
Hospital Utrecht, the Netherlands in 2018 or 2019. Patients were
included if they were able to perform lung function tests (LFTs). Only
reproducible LFT results were included. We excluded patients with
hereditary proximal spinal muscular atrophy (SMA) who had started
treatment with genetic therapies during follow up, as this might provide
an alternative explanation for improvement of LFT results. This study
was approved by the local Medical Ethics Committee. Written informed
consent was obtained from all participants and/or their parents. The
reporting of this study conforms to the STROBE statement5.
Spirometry data (Geratherm Spirostick®) were collected
at the department of pulmonology prior to and 3 months after surgery. We
included results of (Forced) Vital Capacity ((F)VC), the ratio of Forced
Expiratory Volume in 1 second (FEV1) and FVC, and Peak
Expiratory Flow (PEF). All LFTs were measured in sitting position,
without corsets or braces by a small team of professionals experienced
in conducting these tests in children with NMDs and other comorbidities.
All LFTs were measured and reported according to the European
Respiratory Society guideline 6. If patients were
unable to stand to measure height, arm span was used as a surrogate
measure. We reported absolute and standardized LFT values, according to
the Global Lung Initiative 7.
We compared values 0-3 months before and 3-4 months after scoliosis
surgery. In patients with more than three months between the PICU clinic
visit and surgery, LFTs were repeated on the day of admission. We chose
this timing of 3-4 months after surgery, to combine it with regular
orthopedic follow up and consequently minimize the burden for the
patient .
To study the progression rate of LFT results before and after surgery,
we used LFT results obtained during regular follow up in the 2 years
before and after surgery whenever available.