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Myelomeningocele Scoliosis



- See:
       - Orthopaedic Manifestations of Myelomeningocele:

- Discussion:
    - scoliosis in myelomenigocele may have a multifactorial etiology:
           - idiopathic causes;
           - myelomeningocele structural defect;
           - congenital defects
           - paralytic etiology;
    - 15-20% of children who have myelomeningocele have congenital vertebral abnormalities in addition to congenital scoliosis;
    - over-all incidence of scoliosis in pts who have thoracic-level lesion is 85%;
    - all children who are born with an osseous dysraphism at level of T12 or higher, are at risk for the development of a severe scoliotic 
           deformity for which arthrodesis is needed;
    - progression of scoliosis in myelomeningocele is natural;
    - progressive scoliosis in myelomeningocele:
           - may manifest as lower extremity spasticity;
           - MRI is helpful in evaluating these children;
           - diff dx:
                  - tethered cord:
                         - if curve continues to progress despite neurosurgical release of tethered cord, then curve must be stabilized with spinal fusion;
                  - non-functioning shunt:
                         - must be corrected before attempt is made to correct the scoliotic deformity;
                  - Arnold Chiari malformation:
                  - syringomyelia:
                  - hydromyelia:
                  - hydrocephalus:
    - treatment considerations:
           - goal is to have a compensated spine of normal height over level pelvis, w/ preservation of normal sagittal alignment;
           - documented progression of curve is indication for early fusion, just as in child who does not have myelomeningocele;


- Bracing:
    - orthotic treatment is helpful for the more common paralytic curve until the child reaches puberty;
    - although bracing does not alter natural history of deformity, it promotes spinal growth & preserves better sitting posture, esp in pts who 
           have lesion at thoracic level;
    - carefully fitted, custommolded, bivalve plastic total-contact  thoracolumbosacral orthosis provides maximum support and allows 
           monitoring of the skin over pressure-sensitive areas;
    - custom-molded chair insert for sitting is valuable for the child who has high thoracic-level lesion or severe kyphotic deformity;
    - attempts at bracing (TLSO) may fail & require subcutaneous rodding for very young children and fusion later;


- Operative Treatment of Scoliosis:
    - preop eval:
           - aggressive evaluation of urinary tract, treatment of urinary tract infection, & periop ATB are important in reducing wound infections;
           - treatment of the scoliosis without recognition of syringomyelia and Chiari malformation can lead to paraplegia;
    - paralytic scoliosis:
           - treated w/ anterior arthrodesis combined w/ posterior arthrodesis and secure internal fixation, plus bone grafting;
    - luque sublaminar wiring w/ fixation to sacrum;
           - curves > 60 deg require initial anterior release & fusion;


- Selection of fusion level;
     - it is difficult to decide which levels to include in spinal fusion;
          - 55-deg curve that ends at L-3 can probably be corrected satisfactorily w/ anterior/posterior fusion & instrumentation so that sacral
                   fusion will not be necessary;
     - fusion to sacrum:
           - arthrodesis to pelvis is often needed to correct severe pelvic obliquity and dysraphism;
           - in pts w/ high-level myelomeningocele, it is important to fuse to sacrum if curve is major and cannot be corrected below 15 deg;
           - in child w/ low lumbar myelomeningocele who is able to walk, a fusion to sacrum will impair walking ability & confine child to 
                  wheelchair;
           - sacrum should not be fused in walking child unless it is absolutely necessary;
     - high-level myelomeningocele:
           - it is important to fuse to sacrum if curve is major and cannot be corrected below 15 degrees;
     - low level myelomeningocele:
           - in pt w/ low lumbar myelomeningocele who is able to walk, fusion to sacrum will impair walking ability & confine child to a 
                 wheelchair;
     - staged anterior & posterior arthrodesis:
           - in young child, it is important to maintain anterior/posterior fusion, otherwise crank shaft phenomenon" may develop w/continued 
                  progression of curve;
           - staged anterior & posterior arthrodeses are necessary to achieve adequate correction and solid fusion due to absence of 
                 posterior osseous elements, muscle weakness, & lack of ligamentous support in the dysraphic spine,
           - combined anterior & posterior arthrodeses allow for major correction of spinal deformity as well as stabilization of pulmonary
                  function and improvement of respiration;
     - posterior arthrodesis:
           - Luque and CD systems may allow isolated posterior arthrodesis w/o need for anterior fusion;



- Complications:
    - spinal operations in patients who have myelomeningocele have been associatted w/high incidence of complications such as pseudarthrosis,
            loss of correction, & sepsis



Efficacy of surgical management for scoliosis in myelomeningocele: correction of deformity and alteration of functional status.

The crank shaft phenomenon.