The clinical spectrum of lumbar spine disease in achondroplasia.

A retrospective study was done to determine the entire clinical spectrum of lumbar spine disease in 47 adult patients, averaging 27.6 years of age, with achondroplasia. Five distinct clinical categories were defined. Twenty-eight percent of the patients were asymptomatic; 28% had only mechanical or degenerative lumbar pain; 6% had symptoms of a disc herniation; 21% had spinal claudication; and 17% had spinal claudication and objective neurologic deficits. Over 50% of the achondroplastic patients in this series had minor or no lumbar-spine-related symptoms through the third decade. The number of symptomatic patients did not increase in the older age groups. Ninety-one percent of symptomatic patients were 30 years of age or younger at the onset of symptoms. The presence of a thoracolumbar kyphosis, regardless of its magnitude, an L1 interpediculate distance less than 20 mm, and L5 interpediculate distance less than 16 mm, and a large structural lumbar lordosis were found more frequently in patients with disabling symptoms.