Achondroplasia Treatment & Management
- Author: Shital Parikh, MD; Chief Editor: Jeffrey D Thomson, MD more...
The availability of somatotropin (recombinant human growth hormone) has revolutionized the treatment of short stature. Growth hormone is currently being used to augment the height of patients with achondroplasia. The greatest acceleration in growth velocity is seen during the first year of treatment and in those with the lowest growth velocities before treatment. However, no long-term studies exist to determine final height, nor do any randomized controlled studies exist to justify prolonged treatment with growth hormone in patients with short stature.
For maximum benefit, it is recommended that therapy be intiated at a young age (1-6 years).
Most of the orthopedic problems encountered in patients with achondroplasia are related to the spine. Craniocervical stenosis, thoracolumbar kyphosis, spinal stenosis, angular deformities of the lower extremities, and lengthening of the short extremities are the orthopedic problems commonly addressed in achondroplasia.[1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35]
Treatment of spinal canal stenosis
Wide, multilevel laminectomies extending to the pedicles and lateral recesses with foraminotomies may be necessary. Extradural removal of herniated disc material is performed as necessary. The length of decompression usually extends from the lower thoracic spine to the sacrum to prevent recurrence. Maintaining the integrity of facet joints is necessary to prevent postlaminectomy instability. If instability does occur, anterior fusion may be necessary.
To obtain successful results, it is important to ensure that laminectomies are carried out to the appropriate extent, which should be three levels cephalad to the proximal extent of compression, distal to the second sacral level, and lateral to the facet joints. The results of this more extensive approach are encouraging.
Treatment of thoracolumbar kyphosis
Treatment of thoracolumbar kyphosis consists of mere observation for the child who has not begun to walk because spontaneous resolution frequently occurs. Reports exist that demonstrate the efficacy of early prohibition of unsupported sitting. If wedging of the apical vertebra persists after independent ambulation (typically, wedging of T12 or L1), an extension-type thoracolumbosacral orthosis should be used.
If the thoracolumbar kyphosis persists and measures greater than 30° at age 5 years, then surgery should be performed. Surgery is usually in the form of combined anterior and posterior fusion. Posterior instrumentation generally is not recommended, because of the narrow canal size. Placement of any instrumentation (eg, hooks or sublaminar wires) in the canal is contraindicated because of the marked stenosis and decreased subarachnoid fluid space.
If kyphosis is associated with a neurologic deficit such as paraplegia, laminectomy alone is not indicated, because it can destabilize the spine further. Treatment should consist of anterior cord decompression with strut grafting and posterior fusion.
Correction of genu varum
Surgical correction of genu varum may be required. This may be in the form of proximal tibiofibular osteotomy or of proximal and distal fibular epiphysiodesis. Osteotomy is performed when rapid correction of symptomatic deformity is required. It can be performed through small incisions without internal fixation, with long-leg cast immobilization for 6 weeks.
Lengthening of limbs
Limb lengthening of the upper and lower extremities is promoted in Europe.[29, 30, 31, 32, 37, 38] However, the Little People of America (LPA) and the Dwarf Athletic Association of America (DAAA) are generally opposed to these procedures (see Overview, Patient Education).
If lengthening is to be performed, any existing angular deformities should be corrected simultaneously. With the current techniques of distraction osteogenesis, 30 cm of length can be gained. Gradual lengthening of the osteotomy callus (callostasis) or through the epiphyseal plates (chondrodiastasis) can be obtained using monolateral frames or Ilizarov ring fixators.[26, 39] The six-segment lengthening (femur, tibia, humerus) can be performed as staged procedures in various sequences.
A potential exists for major complications during six-segment lengthening. Neurologic injury has been reported in 35% of procedures. Foot drop, vascular compromise, soft-tissue contractures, loss of motion, knee subluxation, infection, psychological changes, and death have been reported with extensive lengthening procedures.
Foramen magnum decompression (neurosurgery)
Narrowing of the foramen magnum may result in a variety of neurologic problems in the first several years of life. Significant improvement of severe neurologic symptoms has been reported with foramen magnum decompression and C1 laminectomy; however, prophylactic surgery is not recommended.
Ventriculoperitoneal shunts are indicated for patients with rapidly progressive head enlargement, increased intracranial pressures, or neurologic signs and symptoms. Neurosurgery is also indicated for other neurologic abnormalities, such as Chiari malformation.
Nutritional counseling is helpful. Obesity is a lifelong issue, and dietary therapy should be initiated early in life.
The following consultations may be considered:
Orthodontist - Maxillary hypoplasia leads to dental crowding and malocclusion, often necessitating orthodontic treatment.
Speech therapist - Although most of the speech problems resolve by the time patients are of school age, children with persistent problems should be referred to a speech therapist
Otolaryngologist - Early recognition and treatment of chronic otitis media is required to prevent hearing loss; relative hypertrophy of tonsils and adenoids due to midface hypoplasia may require treatment; an otolaryngologist may be involved in the treatment of sleep apnea syndrome, for which tonsillectomy, adenoidectomy, and, rarely, tracheostomy are the procedures performed
Geneticist - A clinical geneticist may be of help by providing counseling to the family and may also may be a valuable resource for the pediatrician seeking additional information or consultation; the proper establishment of the mode of inheritance not only aids in genetic counseling but also enables the orthopedist to distinguish achondroplastic dwarfism from other forms of dwarfism, many of which have an autosomal recessive inheritance
Pulmonologist - Pulmonary function should be evaluated, and respiratory complications such as apnea, pneumonia, and cyanosis should be avoided
Pediatrician - The American Academy of Pediatrics Committee on Genetics has issued guidelines to assist the pediatrician in caring for children with achondroplasia and their families  ; occasionally, the pediatrician is called on to advise pregnant women who have been informed of a prenatal diagnosis of achondroplasia
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