Surgical management of thoracolumbar kyphosis in mucopolysaccharidosis type 1 in a reference center

Mucopolysaccharidosis (MPS) I is a rare autosomal recessive lysosomal storage disease. Thoracolumbar kyphosis is an early characteristic feature of the disease. Ossification failure in the anterosuperior quadrant of the vertebral body results in anterior dislocation. This study describes the surgical management of thoracolumbar kyphosis in MPS IH (Hurler syndrome) in a national reference center. Among 72 MPS I patients followed in our institution, we treated surgically 14 MPS IH patients with severe thoracolumbar kyphosis. The decision was made after documented deformity progression. Mean age at surgery was 8 (3.5-15) years. Sagittal imbalance of the trunk was constant. One patient underwent extended fusion for associated scoliosis. We retrospectively reviewed 13 patients who underwent selective circumferential fusion at the thoracolumbar level. Average preoperative kyphosis was +57.5A degrees(+30A degrees; +90A degrees). Surgical correction of the kyphosis was about 66 % and maintained at final follow-up. Fusion was obtained in all patients. Two patients required revision surgery consecutively to a previous posterior-only fusion, as a significant loss of correction occurred. One patient presented delayed neurologic deficit secondarily to cardiac embolism. One patient died postoperatively from cardiorespiratory failure. Surgery is necessary when kyphosis is progressive despite orthopedic management, aggravating the multifactorial trunk imbalance. Regarding our experience, circumferential arthrodesis should be recommended to achieve stable correction. Surgical management requires a multidisciplinary approach due to multisystemic failure and neurological risks specific to metabolic disorders.