When Convex Growth Arrest in the Thoracic Spine fails to controlprogression of a congenital scoliosis: Case Report

Abstract

Congenital scoliosis are one type of Early-Onset Scoliosis (EOS), a paediatric spinal deformity that progresses rapidly before the age of 10. Due to the high risk of spinal curvature aggravation and subsequent thoracic constraints during the critical period for lung development early in life, these young children with EOS may develop impaired pulmonary function. Some of these patients are at risk of developing Thoracic Insufficiency Syndrome (TIS) due to Volume Depletion Deformities (VDD), particularly the Type II (with rib synostosis). In the past, early spinal fusion of the thoracic spine was the standard surgical treatment but resulted in iatrogenic restrictive lung disease due to shortening of thorax “height”. For some of the congenital cases, Convex Growth Arrest (CGA or hemiepiphysiodesis) of the main spinal curvature is a recognized growth-guided surgical technique, appropriate to deal with this type of condition, but the outcome can be rather unreliable and its failure can lead to severe residual chest and spinal deformities that may compromise pulmonary function in the same way.

Case Report: This is a 2 year old boy with Goldenhar Syndrome, a congenital condition with several spine and rib deformities like hemivertebrae, butterfly vertebrae, fused ribs and congenital scoliosis. With all these anomalies present, the thoracic scoliosis progressed to 75º by two years of age and he underwent a CGA in order to stop curve deterioration and hopefully to improve the deformity. However, despite this procedure the scoliosis got progressively worse and at 5y of age had a cobb angle of 114º. Upon discussion of the several alternatives to improve the spinal deformity, a VEPTR (spine to rib) was inserted at the of age five with subsequent repeated distraction program that successfully controlled the deformity. The boy at the age of ten had the curvature almost fully corrected but due to the hospital’s waiting list, the final procedure was only performed by the age of thirteen (with progression of the curvature). He reached skeletal maturity with definitive posterior spinal instrumented fusion in a stable condition with preserved respiratory function leading a normal life, able to play tennis.

Conclusions: For patients at risk of TIS due to congenital EOS and rib synostosis, expandable thoracic distraction device is an alternative growth sparing tool in the armamentarium to correct a severe thoracic scoliosis while preserving thoracic spine lengthening and optimizing pulmonary growth development. Failure of hemiepiphysiodesis often requires more invasive salvage techniques to manage aggressive curve progression. Clinical success should be assessed by the stabilization of respiratory condition and preservation of vertical trunk growth in a balanced spine, rather than by correction of the Cobb angle only.