summary Myelodysplasia is a common group of congenital disorders caused by various chromosomal abnormalities that lead to the failure of closure of the fetal spinal cord and present with anatomic anomalies and neurological impairment of varying degree. Diagnosis can be made in utero with fetal ultrasound. Treatment involves a multidisciplinary approach to address neurological, genitoturinary, and orthopedic manifestations. Epidemiology Demographics 0.1-0.2% incidence Risk factors folate deficiency supplementation can decrease risk by 70% maternal hyperthermia maternal diabetes valproic acid Etiology Genetics chromosomal abnormalities up to 10% of fetuses have a chromosomal abnormality trisomy 13 trisomy 18 triploidy various single-gene mutations Associated conditions orthopaedic manifestations pathologic fractures spine deformities scoliosis kyphosis hip dysplasia hip dislocations contractures knee deformities tibial torsion contractures foot deformities neurosurgical manifestations Type II Arnold-Chiari malformation most common associated congenital abnormality hydrocephalus 70% incidence tethered cord urological manifestations neurologic bladder Special considerations IgE mediated latex allergy results in profound anaphylaxis present in 20 to 70% of patients with this disorder Classification Forms of myelodysplasia spinal bifida oculta defect in vertebral arch with confined cord and meninges meningocele protruding sac without neural elements myelomeningocele protruding sac with neural elements rachischisis neural elements exposed with no covering Function level (described by lowest functioning level) Function level (described by lowest functioning level) Level Function Primary Motion Primary Muscles L2 Nonambulatory L3 Marginal Household ambulator High risk of hip dislocation Hip flexion Hip adduction Iliopsoas (lumbar plexus, femoral n.) Hip adductors (obturator n.) L4 Household ambulator plus Key level because quadriceps can function Knee extension Ankle dorsiflexion & inversion Quadriceps (femoral n.) Tibialis anterior (deep peroneal n.) L5 Community ambulator Toe dorsiflexion Hip extension Hip abduction EHL (deep peroneal n.) EDL (deep peroneal n.) Gluteus med.& min. (superior gluteal n.) S1 Normal ambulator Foot plantar flexion Gastroc-soleus (tibial n.) S2 Normal ambulator Toe plantar flexion FHL (tibial n.) S3,4 Normal ambulator Bowel & bladder function Imaging Radiographs useful for monitoring scoliosis/kyphosis hip dysplasia pathologic fractures MRI change in neurologic exam prompts urgent MRI to rule out cord tethering Studies Labs alpha-fetoprotein (AFP) elevated in 75% of children with open spina bifida obtain during second trimester Pathologic Fractures Introduction fractures of the long bones are common due to osteopenia frequency increases with the higher the level of the defect common in hip and knee in children ages 3 to 7 years of age fractures are often confused with infection osteomyelitis cellulitis Treatment short period of immobilization in a well-padded splint indications fractures in satisfactory alignment technique well-padded cast avoid long-term casting may lead to osteopenia repeat fractures Scoliosis Introduction may result from muscle imbalance (neurogenic) or congenital malformation (e.g., hemivertebrae) defined as curve > 20° higher the functional level, the greater the incidence of scoliosis 100% scoliosis rate with defects in thoracic levels consider cord tethering in rapidly progressing deformities Treatment nonoperative bracing not effective operative ASF and PSF with pelvic fixation indications progressive curve indicated in most situations as bracing is not effective technique anterior fusion required due to dysplastic posterior elements that may impair posterior fusion complications high psuedoarthrosis rate high incidence of infection (15 to 25%) due to poor soft tissue coverage of posterior spine Congenital Kyphosis Introduction present in 10-15% with myelodysplasia usually congenital and progressive Physicalexam Gibbus deformity may cause recurrent skin breakdown due to pressure points when sitting Treatment operative kyphectomy with fusion and posterior instrumentation indications progressive deformity technique check shunt function prior to kyphectomy shunt failure during surgery may result in death Hip Disorders Hip dislocation introduction most common at L3 level due to unopposed hip flexion and adduction treatment nonoperative indications all levels technique close observation operative indications surgical treatment of dislocated hips is controversial Hip abduction contracture introduction can cause pelvic obliquity and scoliosis treatment proximal division of fascia lata and distal iliotibial band release (Ober-Yount procedure) indications contractures interfere with sitting or bracing Hip flexion contracture introduction common in high lumbar or thoracic defects treatment anterior hip release with tenotomy of the iliopsoas, sartorius, rectus femoris, and tensor fascia lata indications contractures greater than 40 degrees Knee Disorders Weak quadriceps introduction common condition affecting children with myelodysplasia treatment KAFO (knee-ankle-foot orthotic) Flexion contracture introduction not as important to treat in wheelchair bound patients treatment hamstring lengthening +/- posterior capsulotomy indications greater than 20 degrees of knee flexion contracture supracondylar extension osteotomy indications older patients those who have failed soft tissue procedures Extension contracture introduction less common than flexion contractures treatment serial casting indications extension contracture limiting ambulation or sitting technique goal is to reach 90 degrees of flexion Tibial rotational deformities (torsion) treatment observation and orthotics Indications children less than 5 years old distal tibial derotational osteotomy indications children older than 5 years Foot and Ankle deformities Introduction very common 60 - 90% incidence due to high incidence of lower nerve root involvement Myelodysplasia foot deformity by level Level Foot Deformity Proper orthosis L1 & L2 Equinovarus HKAFO L3 Equinovarus KAFO L4 Cavovarus AFO L5 Calcaneovalgus AFO S1 Foot deformity shoes Clubfeet (talipes equinovarus) introduction 30% incidence with myelodysplasia most common foot deformity very rigid insensate in the foot (different from idiopathic clubfeet) treatment serial casting indications initial treatment of choice complications high complication rate with serial casting posteromedial lateral release indications failure of serial casting technique perform when child 12-18 months old Foot dorsiflexion deformity introduction seen with L5 or sacral level patients unopposed anterior tibialis causes dorsiflexion deformity treatment posterior transfer of the anterior tibial tendon indications inability to achieve neutral foot with bracing Vertical talus Prognosis Survival and neurologic impairment depend on level of spinal segment involved Untreated infants have a mortality rate of 90-100% Ability to ambulate L3 or above are mostly confined to a wheelchair L5 level patients have a good prognosis for independent ambulation