Cervicothoracic Kyphosis and Spinal Cord Compression in Hurler Syndrome

Hurler syndrome is characterized by significant spinal abnormalities, including cervical instability, odontoid dysplasia, and spinal cord compression. Spinal compression and kyphosis at the cervicothoracic (C-T) junction are also observed but less commonly reported. The present study was conducted to determine the prevalence of C-T kyphosis and spinal cord compression at the C-T junction in patients with Hurler syndrome. In addition, we aimed to evaluate the significance of C-T kyphosis and spinal cord compression in these patients in terms of clinical symptoms or neuromonitoring changes in nonspine surgery.

This retrospective case series examines patients with Hurler syndrome at a single pediatric institution from 2009 to 2023, with 47 included based on available spinal MRIs. Radiographic assessments included the C6-T4 kyphosis, maximal C-T kyphosis, and spinal cord compression using Kang grading for stenosis. Follow-up MRIs tracked changes in C-T kyphosis and new spinal cord compression. The value of C-T kyphosis associated with spinal cord compression (Kang grades 2 and 3) was determined using receiver operating characteristic (ROC) analysis. IONM data, including SSEP and TcMEP, were reviewed for significant changes during surgeries unrelated to the spine.

This study involved 47 patients with an average age of 5 years and 57% male. Initial MRI showed a mean C-T kyphosis of 17 degrees, primarily affecting C7-T3. Follow-up MRIs revealed progressive C-T kyphosis and spinal cord compression. A C-T kyphosis >20 degrees was associated with Kang grade 2 spinal cord compression. IONM during nonspine surgeries identified significant changes in 3 patients. One patient developed postoperative paraplegia following hip surgery performed without IONM. A retrospective review of a prior airway MRI showed a C-T kyphosis of 49 degrees along with spinal canal stenosis.

The manuscript sheds light on the intricate nature of C-T kyphosis in individuals with Hurler syndrome. While the clinical significance and optimal management of this condition are still under discussion, the study underscores the importance of evaluating C-T kyphosis to guide surgical planning and reduce the risk of spinal cord injury in affected patients.

Case series, Level IV.