Congenital Spinal Canal Stenosis with Ossification of the Ligamentum Flavum in an Achondroplastic Patient: A Case Report and Literature Review.

Achondroplasia has an effect on intracartilaginous ossification during the development of the spine resulting in a narrow spinal canal. This abnormal anatomy could make an achondroplastic patient tend to have spinal canal stenosis. We reported a case of congenital spinal canal stenosis with achondroplasia combined with ossified ligamentum flavum (OLF) at the thoracolumbar and lumbar spine, which was treated by decompressive surgery. We reported a 52-year-old Thai male with achondroplasia presented with progressive myelopathy and neurogenic claudication due to spinal canal stenosis. Spinal canal stenosis was observed at T10/11 and L1-L5 and OLF at T10/11 through L5 varying in size. Laminectomy and removal of the OLF were performed at T11 and L1-L5. The patient's neurological symptom improved after the surgery. He could walk with a walker at the time of 6-month follow-up postoperatively. In this report, we describe a rare case of achondroplasia with OLF presenting with progressive myelopathy and claudication symptoms from multiple levels of spinal canal stenosis. Laminectomy, removal of the ossified ligament, and fusion with instrumentation resulted in the improvement of the patient's neurological symptoms and function.