4th International Congress on Early Onset Scoliosis & Growing Spine November 19-20, 2010 Treatment of Kyphoscoliosis and TIS Associated with Myelodysplasia Using the VEPTR in an Eiffel Tower Construct Ajeya Joshi, MD Robert Campbell, MD Davin Cordell, MD Vishwas Patil, MD James W. Simmons, DO, PhD William Koeck, MD Kent Reinker, MD University of Texas Health Science Center at San Antonio (UTHSCSA) San Antonio, Texas Children’s Hospital of Philadelphia Philadelphia, PA

Disclosures A. Joshi, MD Celling Technologies R. Campbell, MD Synthes D. Cordell, MD none V. Patil, MD none J. Simmons, DO, PhD none W. Koeck, MD none K. Reinker, MD none

Introduction Thoracic Insufficiency Syndrome (TIS) is a source of morbidity and mortality in children with spinal and thoracic deformities VEPTR has been a successful treatment for TIS associated with spinal and thoracic deformities We analyzed the effect of VEPTR treatment on spinal, thoracic, and pelvic deformities and TIS in children with myelomeningocele

Background Orthopedic management of myelomeningocele Correct spinal, thoracic, and pelvic deformities Improve respiratory function Maintain spinal growth Surgical management of spinal deformities in myelomeningocele is challenging High infection rates Poor soft tissue coverage High hardware failure rates Myelomeningocele can result in both primary and secondary TIS With improved neurosurgical and urological management of myelomeningocele, orthopedics has become more involved in management of children with myelomeningocele. Number of different strategies have been developed: kyphectomy (Sherrard), fusion (posterior and anterior/posterior) with multiple techniques, growing rods. Kyphosis/scoliosis: relentlessly progressive; to halt progression and correct coronal and sagittal balance Pelvic obliquity: to improve sitting balance, decrease pressure, improve function Complications: Most common: hardware failure, infection, pseudarthroses, shunt insufficiency Niall et al (2004) [aka Goldberg study]; 20 of 24 experienced post-op complications, complicated primary wound healing most frequent; 18 required further surgeries for protruding hardware.

Secondary TIS Thoracic Insufficiency Syndrome Secondary TIS The inability of the thorax to support normal respiration or lung growth Secondary TIS upward pressure of the abdominal contents against the diaphragm, interfering with normal respiration and lung growth It occurs in myelomeningocele due to: Lack of active lumbar extension Severe pelvic obliquity The marionette sign is a clinical manifestation of this phenomenon Primary TIS in myelomeningocele: volume depleting deformities due to fused/absent ribs, thoracic kyhposcoliosis, windswept deformities, and thoracic hypoplasia/shortening Lack of lumbar extension: diminished or absent posterior spinal elements with anterior migration of paravertebral muscles; thoracic or upper lumbar neurological level. Severe pelvic obliquity causes approximation of pelvis to thorax, causing upward pressure against diaphragm.

Objectives To describe an operative technique using VEPTR for children with myelomeningocele To assess the effects of VEPTR on the spinal, thoracic, and pelvic deformities To measure changes in respiratory status To measure response of TIS to VEPTR treatment To identify complications associated with the use of VEPTR in children with myelomeningocele

Materials & Methods Retrospective study Study Criteria Inclusion: Diagnosis of myelomeningocele with kyphoscoliosis Selection for treatment using VEPTR instrumentation Minimum 2 years follow-up Exclusion: prior spinal or thoracic surgeries Patient selection 10 patients met the inclusion criteria; none were excluded 6 males; 4 females Age at first surgery: 7.7 years (range, 1.2-14.1) Length of follow-up: 6.2 years (range, 2.3-12.1) Average age at final f/u = 18 patients with myelomeningocele and kyphoscoliosis 8 had less than 2 years follow-up 3 deceased; 3 received follow-up elsewhere; 2 <?>

Materials & Methods Chart review Radiographic Assessment Demographic data Operative technique and frequency Respiratory status: Assisted Ventilatory Rating (AVR), respiratory rate, capillary blood gases, marionette sign Complications Radiographic Assessment Cobb angle Lumbar kyphosis Pelvic obliquity Space Available for Lungs (SAL) Data analyzed using paired student t-test and Mann-Whitney U test

Operative Technique: Eiffel Tower Construct

Operative Technique: Eiffel Tower Construct

Results Operative Technique Implantation 8 unilateral rib-to-pelvis device 2 staged bilateral rib-to-pelvis devices All received lateral rib-to-rib devices (6 bilateral; 4 unilateral) Replacements Mean of 2.5 surgeries (25 total) 2 for migration; 3 for DM hook fracture; 2 for infection Expansions Mean of 7.8 surgeries (range, 3-15) Unilateral devices: 4 right, 3 left (4) Time between staged implants: 16mo, 5.5mo (24mo, 8yr7mo) Migrations: 2 superior hooks, 2 D-M hooks, 2 inferior hooks Mean number of expansions: 11.9 (range, 6-15) Mean interval betw expansions: 10 months

Results Spinal, Thoracic, & Pelvic Alignment Pre-implant Final F/u Cobb angle: 70.8 46.9 (p = 0.004) Lumbar kyphosis: 42.5 22.3 (p = 0.07) Pelvic obliquity: 24.7 8.6 (p = 0.009) SAL: 0.659 0.880 (p = 0.002) n Pre-Implant Final F/u p-value* Cobb Angle 10 70.8° ±18.4° 46.9° ±17.2° 0.004 Lumbar Kyphosis 6 42.5° ±13.7° 22.3° ±18.9° 0.07 Pelvic Obliquity 24.7° ±11.6° 8.6° ±6.6° 0.009 SAL 0.659 ±0.100 0.880 ±0.057 0.002 * paired student t-test Cobb angle correction (%) = 62.6% Pelvic obliquity correction (%) = 65.2% Criteria for normal lumbar curvature came from Propst et al, Radiographic determination of lordosis and kyphosis in normal and scoliotic children, J Pediatr Orthop, (1983) 3:344-6. Normal children had mean 40° (range, 31°-49.5°) lordosis. All children with a normal lumbar lordosis (n=4) maintained curves. Pre = 37.8°, post = 36.0° (p=0.54). If definition of lumbar kyphosis expanded to less than 30deg lordosis: 19.8 (pre), 3 (post), p=0.05

Results Respiratory Status AVR: (4=full-time mechanical ventilation; 0=no assistance) 8 unchanged (AVR 0) 1 improved (AVR 1 to AVR 0); 1 declined (AVR 0 to AVR 1) p > 0.05 using Mann-Whitney U test Respiratory rate: 29 (pre) 24 (post) CBG: pO2 81.5 (pre) 68.4 (post) (p = 0.15) pCO2 34.5 (pre) 38.8 (post) (p = 0.014) Marionette sign: 6 positive (pre); 0 positive (post) n Pre-Implant Final F/u p-value AVR 10 8 unchanged (AVR 0) 1 improved (AVR 1 to AVR 0) 1 declined (AVR 0 to AVR 1) >0.05* Respiratory Rate 29.3 ±5.4 24.0 ±1.7 n/a CBG: pCO2 34.5 ±2.9 38.8 ±2.1 0.01** Marionette Sign 6 positive 0 positive AVR: (0=no assistance; 4=full-time ventilator dependence) * Mann-Whitney U test ** paired student t-test

Results Complications Device migrations: 6 (in 4 patients) 2 superior cradles 2 D-M hooks 2 inferior cradles Hardware fatigue fractures: 3 (in 3 patients) all D-M hook fractures Wound Infections: 4 (in 4 patients) 3 superficial 1 deep all successfully treated Device migrations: all from hybrid device except inferior cradles Device fractures: 1 wheelchair track racing and weight-lifting with severe flexion, the other 2 occurred with histories of falls from wheelchair Wound infections: 3 device replacements occurred; otherwise treated with I&D, abx,

Conclusions VEPTR treatment is a useful technique for addressing primary and secondary TIS in myelomeningocele Spinal, thoracic and pelvic deformity correction was observed The ‘Eiffel Tower’ construct using bilateral or unilateral rib-to-pelvis hybrid devices with wide base and narrow apex might be most effective for correcting lumbar kyphosis and pelvic obliquity Infections were surgically treatable with implant salvage and acceptable morbidity

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