Growing spinal systems and early onset deformities: is hyperkhyphosis a contraindication?

Abstract

Background: Growing spinal systems are actually used for the treatment of early onset scoliosis. However, they are distraction based systems, so the hyperkyphosis is not considered as a correct indication. Aim of our study is to show if those systems can be effectively used in the treatment of spinal kyphotic deformities. Methods: We retrospectively reviewed 16 paediatric patients affected by kyphotic spinal deformity (minimum T3-T12 kyphosis: 60degree) surgically treated with Growing Rod or VEPTR-like systems from 2006 to 2011. There were 8 males and 8 females, with a mean age of 7 years (range, 4 to 11). The aetiology was: idiopathic scoliosis (5 cases), kyphosis in Morquio disease (1) and in Pott disease (1), congenital scoliosis (3), trisomy 8 (1), Escobar syndrome (1), Prader Willi (1), spondylocostal dysplasia (1), arthrogryposis (2). Growing rod was implanted in 9 cases (always dual rod construct), VEPTR in 9 (always rib to spine construct). Pre-operative main thoracic scoliosis averaged 64degree (range, 10degree to 100degree), lumbar scoliosis 55degree and thoracic kyphosis 71degree (60degree to 90degree), 67degree in patients treated with growing rod and 77degree for those treated with VEPTR. Results: Mean follow-up was 30 months (range, 18 to 67). After the first surgery, thoracic kyphosis was corrected from a mean value of 71degree (range, 60degree to 90degree) to 52degree (21degree to 80degree) (p<0.05); in cases treated with growing rod, kyphosis was corrected from 67degree to 44degree (p<0.05), in cases treated with VEPTR from 77degree to 60degree (p<0.05). At final follow up, after 31 lengthening procedures, a loss of correction occurred on sagittal plane: thoracic kyphosis increased from 52degree to 59degree (p<0.05); in case of growing rod, from 44degree to 50degree (p<0.05), in case of VEPTR from 60degree to 70degree (p<0.05). 15 complications occurred in 8 patients, requiring revision surgery in 7 (4 cases of proximal junctional failure). Conclusions: Our results showed that growing spinal implants can be safely used in the treatment of kyphotic deformities. Due to distraction procedures, a loss of correction on sagittal plane is commonly observed at follow up. The final result is mostly related to kyphosis correction obtained during first surgery: growing rods, through cantilever manoeuvre, seem to grant a better sagittal plane restoration compared to VEPTR.