DAVID J. ABRAHAM, M.D. Resident, Orthopaedic Surgery

J. RICHARD BOWEN, M.D. Chief Department of Orthopaedic Surgery


April 16, 1996


Kg is a 6+6 year old white female evaluated in the orthopaedic clinic for progressive scoliosis, bilateral hip dislocations and diffuse hypotonia with inability to walk.

Past medical history significant for recurrent upper respiratory infections occasionally requiring hospitalization.

Developmental History: 8 pound 6 ounce, full term female with no perinatal events and normal intrauterine movement was developing normally until 6 months of age when parents noticed she stopped moving her legs and lost the ability to roll over.

Pediatric neurologist diagnosed Spinal Muscular Atrophy after reviewing the muscle Biopsy.

Managed with physical therapy and inpatient rehabilitation consisting of intensive physical, occupational and aquatic therapy and the use of long leg braces at age of 2.

Radiographic evaluation at age of 3 showed mild scoliosis and bilateral dislocated hips.

Parents were informed that scoliosis would likely progress and PSF would be needed in the future.

Age 6 scoliosis progressed to 78 degrees and PSF with the unit rod was performed.


A group of disorders characterized by degeneration of the anterior horn cells of the spinal cord and occasionally the neurons of the lower bulbar motor nuclei resulting in muscle weakness and atrophy.

Autosomal recessive disorder that occurs in one in 20,000 live births.

One in 40 to 80 people are carriers of the gene.

Loss of the anterior horn cell is acute event without neurologic progression.

The progression of muscle weakness is a reflection of normal growth that exceeds muscle reserve.

Respiratory function is compromised causing atelectasis and pneumonia and eventually resulting in death .


Based on age of onset and functional capacity at time of presentation .

  1. Type I: Acute Werdnig Hoffman Disease
  2. Type II: Chronic Werdnig Hoffman Disease
  3. Type III: Kugelberg-Welander Disease

No evidence of primary myopathy


Orthopaedic concerns involve the treatment of soft tissue contractures of the lower extremities, hip subluxation or dislocation and inevitable spinal deformity.

  1. Soft tissue contracture:
  2. Hip subluxation/dislocation
  3. Spinal Deformity
1. Curve greater than 40 degrees
2. FVC less than 40 % of normal
1. Long posterior fusion was the best way to prevent secondary curves above and below the fusion
2. Anterior arthrodesis alone was not sufficient to maintain spinal stability
3. Anterior arthrodesis was associated with significant increase in pulmonary complications
4. Pre and post operative PT were essential to preserve function.
5. Spine arthrodesis reduced the rate of pulmonary deterioration but did not prevent its progression

Recommendation: Presently we recommend posterior spinal arthrodesis with segmental fixation from T1 to the pelvis and currently use the Unit Rod System.

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