Improvement in functional gait parameters following corrective thoracolumbar surgery in children affected by Mucopolysaccharidosis 1 (Hurler syndrome)

Rajkumar Sundarapandian,Neil Oxborrow,Simon Jones,Pauline Hensman,Alexander Broomfield

doi:10.1186/s13023-020-01427-3

Abstract

ObjectiveThoracolumbar kyphosis is a common indication for spinal surgery in children with Mucopolysaccharidosis. Functional outcome of spinal surgical intervention has never been published in patients with this rare disease. We present a cohort of patients with Mucopolysaccharidosis 1(Hurler syndrome) who underwent thoraco-lumbar spinal deformity correction and functional outcome assessed by pre-operative and post-operative gait analysis. This study represents the first attempt at presenting a functional assessment of surgical outcome in any Mucopolysaccharidosis subtype.MethodsA retrospective analysis of prospectively collected data was carried out from 11 children diagnosed with this subtype of Mucopolysaccharidosis. All patients underwent thoracolumbar kyphosis correction between the years 2013 to 2016. Gait assessment was performed using GAITRite™ electronic walkway pre-operatively and post-operatively within 9 to 24 months from the index surgery. Walking distance, cadence and gait velocity were the three spatio-temporal parameters analysed. Wilcoxon signed rank test was used to analyse the data and P-Value ≤0.05 was deemed significant.ResultsThere was a statistically significant improvement in walking distance in 9 out of 11 patient post-operatively with a mean increase of 232.06 cms (P = 0.05). There was marginal improvement in cadence by 6.33 steps/min post-operatively (P-value 0.79). Gait velocity also showed a marginal increase by 8.73 cms/sec post-operatively (P-value 0.32).ConclusionThe results of our study suggest that correction of thoracolumbar kyphosis in children with Mucopolysaccharidosis 1 resulted in a significant improvement of walking distance with a trend towards improved gait in the other parameters. Post-operative change in cadence was not statistically significant suggesting that physiological maturation of gait had minimal effect in the specified post-operative assessment timeframe. This study emphasizes that outcomes of spinal surgery in children with Mucopolysaccharidosis 1 should be determined by functional measures aiming to maintain or improve quality of life.

Highlights

The results of our study suggest that correction of thoracolumbar kyphosis in children with Mucopolysaccharidosis 1 resulted in a significant improvement of walking distance with a trend towards improved gait in the other parameters
This study emphasizes that outcomes of spinal surgery in children with Mucopolysaccharidosis 1 should be determined by functional measures aiming to maintain or improve quality of life
Mucopolysaccharidosis 1(MPS1) or Hurler syndrome is a rare autosomal recessive disorder which results in a deficiency of lysosomal enzyme α-L-iduronidase [1]

Summary

Introduction

Mucopolysaccharidosis 1(MPS1) or Hurler syndrome is a rare autosomal recessive disorder which results in a deficiency of lysosomal enzyme α-L-iduronidase [1]. This leads to failure in the degradation of glycosaminoglycans and their accumulation in various systems of the body. The global incidence of MPS 1 was reported as 1 in 100,000 live births [2]. The incidence of MPS 1 in England and Wales was 1.07 per 100,000 live births [3]. MPS 1 exists on a spectrum with severe mutations in IDUA leading to complete enzyme deficiency and more rapidly progressive disease. Standard of care for this phenotype of MPS 1 is Haematopoietic stem cell transplantation (HSCT)

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