Myelodysplasia : Wheeless' Textbook of Orthopaedics

- Discussion:
- disorder of spinal cord development/closure or secondary rupture of developing cord secondary to hydrocephalus;
- term myelodysplasia includes:
- spina bifida occulta
- meningocele: sac without neural elements protruding through defect;
- myelomeningocele;
- rachischisis (neural elements exposed without any covering);
- in utero dx: increased alpha feto protein, w/ high risk infant;
- risk factors:
- folic acid antagonists:
- dihydrofolate reductase inhibitors: (displace folate from the enzyme and block the conversion of folate to active metabolites);
- aminopterin, methotrexate, sulfasalazine, pyrimethamine, triamterene, and trimethoprim;
- note that adequate intake of folate before and during pregnancy may prevent up to 85% of myelomenigocele deformities;
- antiepileptic drugs: carbamazepine, phenytoin, primidone, and phenobarbital;

- Functional ability and evaluation:
- related to level of defect & other assoc congenital abnormalities;
- myelodysplasia level is based on the lowest functioning level;
- L4 is key level because quads can function & allow community ambulation;
- functional ability depends on:
- quadriceps
- scoliosis
- pelvic obliquity
- alignment of lower extremity and trunk
- dislocated hips do not limit functio nor do they cause pain;
- sudden changes:
- changes in function, scoliotic progression, or new neurologic deficit may be associated w/:
- hydrocephalus, (most common);
- consider head CT (70% of myelodysplastics have hydrocephalus);
- tethered cord;
- hydromyelia;