A five-year-old boy with known MPS IV presented in December 1975 for the evaluation of genu valgum and thoracolumbar kyphosis. Physical examination revealed short stature, pectus carinatum, valgus knee deformities, and a flexible thoracolumbar kyphosis. Neurological examination revealed normal findings. The patient subsequently was not seen again for five years. In January 1981, he presented with a decreasing ability to walk and had been using a wheelchair for three months. He held the head in extension and had a 50° arc of lateral rotation. The thoracolumbar spine still demonstrated a flexible kyphosis. Neurological examination revealed grade-3 (of 5) motor strength in both the upper and lower extremities. Sensory function was intact in all four extremities. Hyperreflexia was present in both lower extremities, with bilateral sustained clonus and a positive Babinski reflex in both feet. Flexion and extension lateral radiographs demonstrated odontoid hypoplasia with diminished space available for the cord of 9.5 mm without evidence of instability (Figs. 1-A, 1-B, and 1-C). This finding was confirmed on a myelogram (Fig. 2), which demonstrated substantial cervical spinal stenosis at the C1 level as demonstrated by the hourglass appearance of the contrast medium stream. Magnetic resonance imaging was not available at that time. The family declined surgery at first but returned two months later with the patient lying in a stretcher; the patient was having difficulty breathing and had grade-2 (of 5) strength throughout the extremities.
Posterior decompression of C1 and fusion from the occiput to C2 with wires and Gallie bone graft was performed without complication (as later described by Dormans et al. in 199513) (Fig. 3). Postoperatively, the patient was stabilized in a halo vest for three months. He slowly regained full neurological function and walking ability. Radiographic examination demonstrated propagation of the fusion down to C3 at the time of the most recent follow-up (Fig. 4). One year after cervical spine fusion, at the age of eleven years, the patient underwent distal femoral osteotomies to correct valgus deformities of both knees.
The patient was reevaluated yearly for twenty-six years. When the patient reached the age of thirty-seven years, increased cervical lordosis had been present for more than twenty years (Fig. 5). Neck motion was limited to 20° of lateral rotation in each direction and flexion was limited to just past neutral secondary to the previous fusion. The patient had hyperreflexia in both knees and ankles, which had been present for many years and was stable. Manual muscle testing revealed overall lower extremity strength of grade 4 (of 5), which also had been stable for many years. The patient had a minimal gibbus deformity, and the most recent lateral radiograph demonstrated 30° of thoracolumbar kyphosis. Hip and knee flexion were both 110°, with full hip and knee extension. The patient was able to walk in the home but used a walker because of arthritis of the left knee. He used a motorized scooter in the community. At the time of the latest follow-up, he had recently retired from working as a bilingual (Spanish-English) translator.