Medical Student University of Massachusetts Chan Medical School
Introduction: Achondroplasia is the most common human skeletal dysplasia, with an incidence of approximately 1 in 20,000 live births. The incidence of tandem spinal stenosis (TSS) of the lumbar and cervical spine has been reported as high as 23.7% in the general population. In achondroplastic patients, spinal stenosis frequently presents initially in the thoracolumbar spine, but the incidence of TSS has not been reported. We sought to quantify the incidence of TSS in achondroplastic dwarfism to improve diagnostic workup of spinal stenosis in this patient population.
Methods: 61 adult patients with achondroplasia and a documented history of moderate-to-severe lumbar stenosis, and records of cervical spine imaging, were identified from a multinational database from two large academic medical centers. We compared the number of patients with lumbar-cervical TSS to the total number of patients with lumbar stenosis, and compared this proportion to the incidence of TSS in patients without achondroplasia (23.7%) using a Fisher Exact Test.
Results: Of the 61 cases that met inclusion criteria, 39 cases showed a documented history of moderate-to-severe cervical cord compression in addition to lumbar stenosis (63.9%). A significant difference exists between this proportion and the incidence of TSS in patients without achondroplasia (23.7%) (p < 0.001). Among 39 patients with TSS, lumbar stenosis was identified first in 33 patients (84.6%).
Conclusion : The incidence of TSS is significantly higher in the examined cohort of patients with achondroplasia compared to patients without achondroplasia. Lumbar stenosis was identified first in the majority of these patients. This suggests that cervical spinal imaging should be considered in the management of lumbar stenosis in achondroplastic patients, particularly in the setting of mild-to-moderate myelopathic symptoms. Study limitations include the fact that cervical spine MRI’s were often ordered in the setting of cervical cord compression symptoms rather than prophylactically.
