[Neurosurgical aspects in achondroplasia: evaluation and treatment]

Achondroplasia is the most common genetic disorder associated with bone dysplasia. The mode of inheritance is autosomal dominance, while most cases appear to represent a new mutation. Achondroplastic patients suffer from dwarfism, and from typical features of the head and limbs (rhizomelia, macrocephaly, frontal bossing and kyphosis). Half of the patients show various neurological complications. The most serious complication of achondroplasia is respiratory impairment, apnea and sudden infant death, resulting from compression of the medulla oblongata. This study describes the neurosurgical sequels in 10 achondroplastic patients, who underwent 12 surgical procedures. The average age was 14 years (ages ranged from 3 months to 40 years). The patients suffered from back pain, muscle weakness, incontinence, hypotonia, psychomotor delay, apnea and respiratory arrest. Four patients were diagnosed as suffering from obstructive sleep apnea. Craniocervical MRI showed: narrowing of the foramen magnum, fusion of C1, spinal stenosis, and severe cervicomedullary or spinal cord compression. In 5 patients the MRI also showed ventriculomegaly of the lateral and third ventricles. Seven patients underwent foramen magnum decompression and C1 laminectomy. Three patients with severe spinal cord compression underwent laminectomy of the involved spines (T12-L5). Two of the patients required more then one operation due to the recurrence of their neurological symptoms. There was no need for duraplasty or shunt procedures. The average hospital stay was 6 days. Eight patients showed improvement or resolution of symptoms, with an average follow-up period of 13.5 months after the last operation (ranged 6-24 months). We conclude that early neurological and MRI evaluations are required in achondroplasia patients, in order to prevent the high morbidity and mortality during infancy and childhood. In adults, MRI evaluation is needed if the patient has neurological symptoms. Early identification and immediate cervicomedulary decompression procedure can prevent the serious complications occurring in achondroplasia, including respiratory failure, apnea and sudden death.