Research

Purpose: Bone marrow transplantation increases longevity in Hurler syndrome (mucopolysaccharidosis type I-H) that in turn increases the complexity of spinal deformity must be addressed. We describe the surgical management of spine deformities in 12 MPS patients.
Methods: Spinal deformities included eight patients with thoracolumbar or lumbar kyphosis/kyphoscoliosis, three with thoracic scoliosis, and one combined cervicothoracic and thoracolumbar kyphosis. All nine thoracolumbar or lumbar kyphosis/kyphoscoliosis curves were treated with circumferential fusion, four with posterior instrumentation and five without instrumentation. Seven patients had autologous rib strut grafts and two had autologous rib as segmental interbody graft. The scoliosis patients (3 cases) were treated with posterior fusion with instrumentation. All patients had cast or brace for a minimum of 6 months post-surgery.
Results: The follow-up was from 24 months to 8 years 4 months. Average age at initial surgery was 8 years 9 months (2+6 to 15+10). Kyphosis was reduced from 79° (60°-91°) prior to surgery to 47° (20°-74°) at final follow up. Loss of correction greater than 10° was observed in two uninstrumented, strut graft patients (one due to graft resorption and dislodgement, one due to graft resorption and pseudoarthrosis) and in one instrumented interbody graft patient. This occurred above the anterior fusion region. Two cases with autogenous rib interbody graft had no pseudarthrosis or graft complications, in addition to a third patient who has healed her interbody grafts but was not included due to short follow-up. The four scoliosis curves were corrected from 55° pre-surgery to 25° at final follow-up. This includes one patient who had initial surgery at age 8 and required a subsequent surgery at age 9 due to crankshaft phenomenon. Two patients (17%) had superficial wound infections. There were no neurological complications.
Conclusion: Although hypoplastic vertebrae, osteopenia and soft tissue alternation increases the technical difficulty and contributes to correction loss, significant correction of kyphosis and scoliosis can be achieved and maintained. Resorption of multilevel anterior struts is common. Instead, we recommend interbody autogenous rib grafts for anterior spinal fusion.