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Neurofibromatosis

Neurofibromatosis (NF) is a disease that affects the growth of nervous tissue. Tumors can grow on nerve cells either on or beneath the skin anywhere in the body. These tumors are usually benign (not cancerous) but can be disfiguring. NF can cause a number of problems from skin changes, bone deformities to developmental abnormalities.

What causes Neurofibromatosis?

There are two different forms of NF, type 1 and type 2. Each is caused by a defect in a specific gene. Type 1 (NF1) also known as von Recklinghausen disease, is the most common type of neurofibromatosis. Occurring in 1 out of 4,000 births, it affects mainly the nerves on the outer parts of the body. Type 2 (NF2) is less common, only occurring in 1 out of 40,000 births. It mainly affects the central nervous system, causing tumors in the brain and spinal cord.

Neurofibromatosis 1

Symptoms usually appear early in life and include:

  • Multiple birthmarks Neurofibromas
  • Tumors that grow from the nerves
  • Small brown tumors that can appear in the iris (colored part) of the eye
  • Skeletal abnormalities

Neurofibromatosis 2

Diagnosis may be difficult to diagnose without a family history because symptoms don’t appear until teenage years or later. Symptoms include:

  • Hearing loss, beginning in the teenage years/early 20s
  • Auditory nerve tumors, which can lead to hearing loss
  • Other complications such as ringing in the ears, headaches, facial pain/numbness and trouble with balance

Orthopedic Concerns

Skeletal deformities associated with NF1, which include:

Congenital Tibial Deformity or Fracture
Anterolateral tibial bowing occurs at birth and is characterized by the affected leg bowed forward and usually shortened. By age two the bowed tibia fractures spontaneously and does not heal, which forms a pseudoarthrosis (non-union). Bracing is used to prevent the congenital tibial deformity from fracturing. Surgery is needed to treat congenital tibial fractures. These fractures have low healing potential, and multiple surgeries may be necessary.

Limb Length Discrepancy
A discrepancy is noted when there is a difference in the length of either the arms or legs. Arm length discrepancies usually do not cause any significant problems in function. Most functional problems are associated with significant leg length discrepancies. Limb length discrepancy is usually mild and is actually quite common in the population. Mild leg length discrepancy is a normal variant that does not require any surgical treatment, but shoe lifts may be prescribed to help alleviate some symptoms. Larger differences may require surgical treatment such as leg shortening or lengthening using an external fixator.

Scoliosis
This is a curvature of the spine greater than 10 degrees. Diagnosis is made with radiographs of the spine to evaluate the amount of curving. Treatments include observation if there is mild curvature of less than 20–30 degrees, application of a brace for moderate curvature of 30–40 degrees, and a posterior spinal fusion with instrumentation for severe curves of greater than 50 degrees.

Treatment

Since the symptoms of Neurofibromatosis can vary, the treatment will depend on the patient. In many instances, patients will require several specialized physicians to be involved in their care. Bone deformities will need to be addressed by an orthopedic specialist.