Does posterior fusion prevent parasol deformity of the chest in inmature patients (Risser sign 0 and open triradiate cartilage of pelvis) with MSA type II ? N. Ventura PhD., A. Ey-Batlle M.D, I.Vilalta M.D., Celeste Tavolaro M.D., P. Domenech M.D.

The scoliosis secondary to Spinal Muscular Atrophy (SMA) type II in inmature patients (Risser sign 0 and trirradiate cartilage of the pelvis ) can be treated by posterior fusion (PF) or growing rods (GR). Many SMA have a ribs collapse known as “parasol chest”. 12 Y.O.SMA Posterior fusion 8 Y.O. Growing Rods INTRODUCTION

Growing rods apply to patients with SMA type II, respect the growth of the spine but do not avoid the collapse of the ribs and the chest deformity (parasol phenomenon) Albert Fujak et al, Arch Orthop Trauma Surg (2012). McElroy MJ et al, Spine, 2011 This study compare radiographic parameters in the thoracic spine and chest shape between SMA type II inmature patients treated with growing rods (GR) versus posterior fusion (PF) YO mm 221mm 6 Y:O: mm 218 mm BACKGROUND

 Retrospective radiographic study type case report including a total of 22 SMA type II inmature patients  11 Patients treated with GR, average age 8.4 Y. ( ), mean follow up 5.4 Y ( )  11 pateints treated with PF, average age 10.3 Y. ( ), mean follow up 8.9 Y. (4.6-16)  Spinal curve and thoracic shape was quantified using Cobb angle, T.1-T.12 length, T.1-S.1 length and thoracic width at T.6 and T.12. MATERIAL AND METHODS

Preoperative and postoperative : Cobb angle A.P and L., T.1-T.12 length, T.1-S.1 length, T.6 thoracic width, T.12 width T.1-T.12 Length T.1-S.1 Length Thoracic width T 6 Thoracic width T12 T.W. T6 T. W. T.12 T.1-T.12 length T.1-S.1 length RADIOGRAPHIC STUDY

GR patients group:  Mean preoperative Cobb angle 92º (70º-111º) and at the last control 40.4 º ( º) with a % of correction of 56.7% (28 – 84%)  T.1-T.12 length grew a mean of 66.1 mm ( mm)  T.1-S.1 length grew a mean of 122 mm ( mm)  Mean preoperative T.6 thoracic width was 154 mm ( mm) and at last control 136 mm ( mm), with a mean difference of - 18 mm (- 39/+14 mm).  Mean preoperative T.12 thoracic width was 193 mm ( mm), and at the last control 205mm ( mm) with a difference of 11 mm (-47/+37 mm). RESULTS

SMA type II,G.R, 6.8 Y., ( ), 11 lengthening procedure + definitive posterior fusion at 14 Y, significant descreased of the thorathic width at T.6 and T.12 Preop. Last lengthening 2006 T. W.T.6 : - 39 mm Definitive P.F. T.WT mm Y 14 A

PF patient group :  Preoperative Cobb angle 82º (66-98º), at the last control 40º (32- 50º) with a % of correction of 51% /(37-64%)  T.1-T.12 length grew 60 mm (44-75mm) from pre to latest control  T.1-S.1 length grew 83 mm (1-114 mm) from pre to latest.  Mean preoperative T.6 thoracic width was 174 mm ( mm), at last control was 192 mm ( mm), the difference was 18mm (-14/+ 34 mm).  T.12 thoracic width was preoperative 214 mm ( mm) at last control was 259 mm ( mm) the difference was 45 mm (+13/+75 mm) RESULTS

mm 213 mm 10 Y.O mm 291 mm + 45 mm + 78 mm 22 Y.O. SMA tipe II, D.P.F. At 10 Y.O., Risser’s sign 0, T.C.P. opened. Significant increase of thoracic width at T.6 and T.12

182 mm 212 mm 10 Y.O YO 208 mm + 16 mm 275 mm+ 63 mm 24 Y.O. Civil engineer BIPAP during night SMA type II, definitive posterior fusion at 10 Y.O. T.6 width increased 16 mm and the T.12 width 63 mm. The patient who is a civil engineer use the BIPAP during the night

Scoliosis secundary to SMA type II in inmature patients can be effectively manage with definitively posterior fusion or with growing rods. Early posterior fusion obtains similars results in crontrolling curve angle, pelvic obliquity, thorax length and thorax width at T.6 an T.12 that GR without the morbidity of succesives distractions. CONCLUSIONS