Radiographic Parameters Correlating with Success of Mehta Cast

Radiographic Parameters Correlating with Success of Mehta Cast Utilization in Infantile Idiopathic Scoliosis Hamid Hassanzadeh, MD; Sreeharsha Nandyala, BA; Blaine Manning, BS; Amit Jain, MD; Kim Hammerberg, MD JHU

DISCLOSURES • None JHU University of Virginia Orthopaedic Surgery

INTRODUCTION • Infantile scoliosis indicates curves presenting at 3 ys of age or less • Scoliotic deformities presenting before 5 ys have been associated with a greater risk of cardiopulmonary complications and other comorbidities JAMES JI. . JBJS Br 1954 Branthwaite MA. Br J Dis Chest 1986 JHU University of Virginia Orthopaedic Surgery

INTRODUCTION • Treatment: • Non-operative – Mehta Casting • Operative • Growing Rod • VEPTR Mehta MH. J Bone Joint Surg Br 2005 JHU University of Virginia Orthopaedic Surgery

GOALS Identify patient factors & radiographic parameters associated with sustained curve correction in IIS patients that undergo serial plaster casting JHU University of Virginia Orthopaedic Surgery

METHODS • Retrospective review of patients who underwent Mehta casting for IIS at a single institution by a single surgeon • Consecutive series of 45 pts • Patient Characteristics • Complications • Radiographic parameters JHU University of Virginia Orthopaedic Surgery

RADIOGRAPHIC PARAMETERS • Cobb angle of the coronal deformity • Focal deformity • Rib vertebral angle difference (RVAD) • Height of the concavity & convexity of the apical 3 vertebrae • Concave-to-convex height ratios JHU University of Virginia Orthopaedic Surgery

CASTING TECHNIQUE • Derotational & translational forces on the deformity level • The precise technique varied based on type & location of the curve • Casts were changed routinely every few months JHU University of Virginia Orthopaedic Surgery

RESULTS Patient Characteristics Male Female 18 (40%) 27 (60%) Mean Age at Start of Casting (mos) 18. 8 (9. 5) Mean Age at Last Cast (mos) 35. 9 (14. 1) Mean Age at Final Follow up (mos) 52. 3 (23. 7) Mean Total Number Casts 7. 6 (2. 9) Mean total Follow up (mos) 37. 7 (19. 7) JHU University of Virginia Orthopaedic Surgery

RESULTS Radiographic Parameters Pre-Cast Last Cast p-value 22 (49%) 23 (51%) 22 (49%) - 1. 5 cm 1. 6 cm 0. 69 Mean Curve Major 52. 7° 25. 6° <0. 001 Mean RVAD 32. 3° 18. 0° <0. 001 Mean Focal Deformity 30. 5° 17. 4° <0. 001 Curve Type Left Right Mean CPL JHU University of Virginia Orthopaedic Surgery

RESULTS Mean Vertebral Heights Pre-Cast to Last Cast 16 Pre-Cast 14 p<0. 001 Last Cast p<0. 001 12 p<0. 001 10 8 6 4 2 p=0. 03 p<0. 001 e: Co nv m (m ca ve C on -1 ex ex -1 C on Ap Orthopaedic Surgery ex ) ) m (m Co nv 1 ex Ap 1 ex + Ap ex : C on ve Co nc a +1 C o ex University of Virginia Ap m (m ve ex Ap ve x ) m ) (m x Ap ex ve nc a C o ex + 1 Co nv : C on ve e ex C on c av Ap JHU Ap A pe x C on ve x ( (m m ) ) 0

RESULTS Radiographic Parameters p-value 23 (51%) 22 (49%) - Final Follow -Up 16 (35%) 22 (49%) 7 (16%) 1. 62 1. 63 0. 98 Mean Curve Major 25. 6° 16. 2° 0. 04 Mean RVAD 18. 0° 14. 1° 0. 26 Mean Focal Deformity 17. 4° 11. 5° 0. 06 Last Curve Type Left Right Neutral Mean CPL (cm) JHU University of Virginia Orthopaedic Surgery

RESULTS Mean Vertebral Heights Last Cast to Final f/u 16 14 12 Last Cast Final Follow-Up p=0. 11 p=0. 04 p=0. 07 p=0. 01 p=0. 003 10 8 6 4 p=0. 05 p=0. 14 p=0. 17 2 JHU University of Virginia m Co n (m ca ve : ca ve Ap ex -1 C on -1 ex Ap Orthopaedic Surgery ve x ) ) m (m ex Co nv 1 Ap ex Co nc a Ap ex + 1 Co nc a ve ve : C on (m m ve x ) ) ex Ap ex + 1 Co nv ex Ap nc a C o ex Ap (m m ve x : C on ve ve nc a C o ex Ap A pe x C on ve x ( (m m ) ) 0

RESULTS Factors Correlated with Sustained Curve Correction from Last Cast to Final Follow-up r B-Statistic p-value of B-Statistic Rotation Correction from precast to last cast 0. 71 0. 02 0. 79 Concave-to-Convex Ratio Improvement From precast to last cast Apex +1 Apex -1 Apex 80% Cobb angle improvement from precast to last cast Left Sided Curve 0. 72 0. 86 0. 63 0. 28 0. 04 0. 53 0. 19 0. 04 0. 69 <0. 001 0. 03 0. 38 0. 10 0. 13 0. 07 Focal Deformity Correction from precast to last cast 0. 86 0. 49 <0. 001 JHU University of Virginia Orthopaedic Surgery

RESULTS Complications None 28 (62%) Skin Reaction 10 (22%) Respiratory 3 (6%) Nausea 2 (4%) Progression of 3 (6%) curvature Noncompliance 1 (2%) 4 patients were transitioned to surgery JHU University of Virginia Orthopaedic Surgery

DISCUSSION • IIS has potential for recovery & can be reversed when treated in its early stages • Hüter-Volkmann principle plays an integral role with Mehta casting • With proper casting, growth can be channeled into a corrective mechanism JHU University of Virginia Orthopaedic Surgery

CONCLUSION • This study underscores the association of Mehta casting with significant curve correction • Radiographic parameters associated with successful Mehta cast application: – improvements in focal deformity – concave-to-convex height ratios for +1 and -1 apical vertebrae after final casting. • By delaying or sparing IIS patients from surgery & normalizing the spinal curvature, Mehta casting remains a viable treatment option for symptomatic IIS JHU University of Virginia Orthopaedic Surgery

THANK YOU JHU University of Virginia Orthopaedic Surgery