Abstract
Background: A sharp, localised, thoracolumbar gibbus is pathognomonic of the mucopolysaccharidosis (MPS) group of disorders, the most common of which is Hurlers syndrome (MPS I). Untreated patients with this disease run an inevitable course of neurological and physical degeneration until death within the first decade. Haemopoietic stem cell transplantation (HSCT) has resulted in considerable improvement in survival with amelioration of many of the symptoms and signs which characterise this disease. Data, however, is disappointing in relation to the impact of HSCT on skeletal dysplasia. This study reviews the natural history of spinal deformity in Hurler’s syndrome after HSCT in infancy.
Methods: Twenty three patients (12 male and 11 female), transplanted at a mean age of 0.9 years ± 0.47, (range 0.27 – 1.8yrs) were investigated, of whom 19 were at least two years post-HSCT and were included. HLA identical donor sources included unaffected or heterozygote family members, unrelated adults or cord blood. Mean age at review was 9.4 years ± 4.57, (range 2.5 – 18.4yrs). Serial measurements of the thoracolumbar spines incorporated clinical records, radiographs and surface topography. The thoracolumbar gibbus was measured on lateral spinal radiograph using the standard adaptation of the Cobb method. Two segments of the spine were documented: the gibbus itself and the thoracic profile above it. Clinical assessment and surface topography were contrasted with this.
Results: At presentation, all showed the characteristic gibbus at the thoracolumbar junction, with a flat and stiff thoracic spine above. Three patients underwent surgery to correct or maintain the gibbus, which was unsuccessful in two; the third is stable, but still young. Two patients have developed scoliosis: one in the juvenile period and one in infancy. Three female patients are now post-menarchal and have shown no progression of their gibbus. One male patient, now aged 19 years, had significant progression of his gibbus at puberty, but is now stable, untreated and cosmetically acceptable. The remainder are still pre-pubertal but their deformities are not currently progressive.
Conclusion: The fate of the spinal deformity in untreated MPS-I has been poorly documented, as the condition was invariably fatal from cardiorespiratory failure during the first decade. These interim results suggest that, while the deformity persists and may become more pronounced during growth and adolescence, it does not significantly impact on quality of life. The considerations which usually dictate intervention in other spinal deformities of childhood may not necessarily apply and should be approached with caution. The more recent availability of recombinant human -L- iduronidase adds further interest to the management of these patients and warrants cautious expectation , in the context of experience gained in these groups of patients. In conclusion atients with MPS I have complex multisystem disorders, independent of their orthopaedic status. While monitoring their spinal deformity is indicated, over-intrusive investigation and treatment may be counterproductive.
The abstracts were prepared by Mr Colin E. Bruce. Correspondence should be addressed to Colin E. Bruce, Consultant Orthopaedic Surgeon, Alder Hey Children’s Hospital, Eaton Road, Liverpool, L12 2AP.
