The Hip: Preservation, Replacement and Revision

Orthopaedic Manifestations of Myelomeningocele

- Discussion of Myelodysplasia

- Spinal Deformities:
    - vertebral column development:
    - scoliotic & kyphosis in myelomeningocele may be either congenital or paralytic, or combination of both;
    - scoliosis in myelomenigocele:
    - kyphosis in myelomenigocele:
         - need to distinguish between 2 distinct types of kyphosis both of which are centered over mid lumbar segment;
               - C shaped curve w/o rigid segment;
               - more progressive S shape curve w/ rigid kyphosis which often has vertebral anomalies;
         - pts less than 1 yr of age w/ a curve less than 90 deg can be expected to progress 8 deg / yr;
         - pts older than 1 yr w/ curves greater than 90 deg may progress 13 deg / yr;
         - radiographs:
               - need to measure cobb angle on lateral radiographs;
               - need to measure distance of kyphosis from line connecting C1 to S1;
         - indications for treatment: (resection of kyphotic segment);
               - increasing spinal deformity;
               - respiratory deformity or crowding of abdominal contents;
               - failure of skin ulcerations to heal;
         - treatment:
               - surgery should be delayed as long as possible inorder to delay recurrence;
               - patent shunt is essential to prevent acute hydrocephalus, which can result from spinal sac excision usually necessary with kyphectomy;
               - resection of kyphosis w/ local fusion or fusion to pelvis may be required;
               - kyphectomy for severe congenital kyphosis in pts with thoracic-level myelomeningocele is indicated for sitting imbalance or w/ skin problems occur over the apex;
               - cordotomy:
                       - in the report by Lalonde F and Jarvis J (1999), the authors performed a cordotomy as a part of spinal correction in myelomeningocele patients at an avg age of 9 years;
                              - cordotomy was performed at or below the level of the kyphosis;
                              - the mean kyphotic angle improved from 117 deg to 49 deg;
                              - only one patient showed deterioration of bladder function, whereas 8 out 9 patients showed improvement in bladder capacity and compliance;
         - references:
               - Kyphotic deformity in patients who have a myelomeningocele. Operative treatment and long-term follow-up.
               - Congenital kyphosis in myelomeningocele.  The effect of cordotomy on bladder function.

- Upper Extremity:
    - pt w/ incr upper extremity weakness should be evaluated for arrested hydrocephalus due to an Arnold Chiari malformation;

- Lower Extremity:
    - functional prognosis:
           - functional motor level is major determinant of prognosis and outcome
           - quadriceps strength is the most important determinant of ambulation in adulthood;
                   - significant quadriceps weakness indicates a high lumbar neurologic level, and the prognosis for long term ambulation is poor;
           - in children and adolescents, sacral and L5 lesions are consistent w/ community ambulation;
                   - where as the vast majority of children will be community ambulators, upto one third of adults will have a significant decline in their ability
                          to walk by adulthood (relying instead on wheel chairs);
           - even w/ sacral level myelomenigocele long term functional results in adults is not promising;
                   - adults will commonly experience progressive motor and sensory loss in the foot and ankle (leading to reclassification of low lumbar level dysplasia);
           - references:
                   - Ambulation in patients with myelomeningocele: A multivariate statistical analysis.  
                   - Myelomeningocele at the sacral level. Long-term outcomes in adults.
                   - Walking ability after transplantation of the iliopsoas: A long term follow-up
    - hip in myelomeningocele:
    - fractures:
           - frx are common in myelodydysplasia, most often about knee & hip in 3-7 yo age group, & are dx'ed by redness, warmth, and swelling;
           - fractures usually heal with abundant callus;
           - references:
                   - Fractures in patients who have myelomeningocele.
    - myelodysplastic knee:
           - usually includes quadriceps weakness (usually treated with KAFO's);
           - recurvatum (associatted with clubfeet and hip dislocation) is rarely problem & can be treated with early with serial casting and KAFOs;
           - tenotomies (quadriceps lengthening) are sometimes required;
           - valgus deformities are usually not a problem;
           - sometimes, iliotibial band release or late osteotomies may be needed (if they interfere with sitting or if they lead to foot deformities or ulceration);
    - foot deformities in myelomeningocele:
           - congenital vertical talus:
           - club foot:
           - ankle vaglus:
                 - resulting from disparity in fibular versus tibial growth;
                 - treated w/ tibial osteotomy or hemiephysiodesis (older pts) if fibula is shortened, or Achilles tendon tenodesis to the fibula (younger patients);
           - hindfoot valgus:
                 - total contact AFOs may be used initially;
                 - triple arthrodesis should be avoided in most myelodysplastics & is used only for severe deformities with sensate feet;
           - calcaneovalgus deformity:
           - talipes calcaneus:
                 - arises from unopposed pull of tibialis anterior tendon, toe extensors or the peroneal tendons;
                 - treatment:
                      - non-operative treatment for talipes calcaneus is limited;
                      - always seek to determine exact muscle imbalance causing this deformity;
                      - w/ mild deformity, simple resection of the offending tendon will allow foot to be brought into satisfactory position;
                      - in phase transfer: involves transfer of peroneal tendons to the os calcis;
                      - out of phase transfer: transfer tibialis anterior thru interosseous membrane to os calcis;
                      - operative intervention is delayed until child is 18 months old;
                      - after age of 6 years, the deformity is usually osseous, and a posterior displacement osteotomy of the calcaneus may be necessary;
                      - after age of 10 years, triple arthrodesis may be done for severe deformity that is not controllable by bracing or an osteotomy;
                             - however, many surgeon's are adverse to performing a triple arthrodesis in insensate skin;
                 - references:
                      - The results of tenodesis of the tendo achillis to the fibula for paralytic pes calcaneus.
                      - Treatment of the calcaneocavus foot deformity.

Current Concepts Review.  Orthopaedic Aspects of Myelomeningocele.

Effectiveness of muscle transfer in myelomeningocele hips measured by radiographic indices.

Rotational deformities of the lower limb in myelomenigocele.  

Assessment and management of the lower extremity in myelodysplasia.    NC Carroll.  Orthop Clin North Am. Vol 18. 1987. p 709-724.

Reduction in Neural-Tube Defects after Folic Acid Fortification in Canada

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Wednesday, April 25, 2012 11:08 am