1. Surgery of Spinal Deformities Rizzoli Orthopaedic Institute Bologna, Italy Surgical options in progressive scoliosis in pediatric patients with Neurofibromatosis type I Konstantinos Martikos, Francesco Lolli, Mario Di Silvestre MD, Alfredo Cioni, Stefano Giacomini, Mauro Spina, Tiziana Greggi,

2. Background Spinal deformity  Spinal deformity in approximately 49% of patients with NF1 (1) 2 types of scoliosis in NF1 Non-dystrophic  progressession similar to AIS  treated as an AIS Dystrophic (2)  more severe  osseous abnormalities that complicate treatment  early and aggressive surgical intervention is necessary

3. Dural ectasia  bone erosion  meningocele Vertebral scalloping  <3mm thoracic spine <4mm in lumbar spine Background Dystrophic alterations Rib Penciling  may cause paralysis Dumbbell lesion  canalar neurofibromas  expand through foramen

4. Orthopedic featuresModulation  a process by which dystrophic characteristics develop over time (3) C. S. Female 5 yrs C. S. Female 10 yrs  Modulation should be carefully assessed to prevent progression of deformity in young patients under the age of 10 years.  Modulation rate is reported 65%;  Occures in 81% of NF-1 patients with scoliosis before the age of 7.

5.  Retrospective evaluation of surgical outcomes  23 consecutive patients, between 4 and 11 years, with severe progressive scoliosis in NF1.  Average Cobb angle before surgery: 48° (min. 38°, max. 82°)  Skeletal maturity according to Risser sign was 0 in all patients.  Mean age at first surgical procedure: 9.1 years (min. 8 yrs, max. 11yrs)  Mean follow up: 4 years (min. 18 mos, max 15 yrs). Materials and methods  Group A (14 patients): Thoracic kyphosis inferior to 50°. Posterior only instrumentation.  Group B (9 patients): Thoracic kyphosis superior to 50°. Combined anterior and posterior instrumented arthrodesis. Patients retrospectively divided into 2 Groups

6.  Average correction rate of Cobb angle: 60%.  Overall complication rate: 24%.  Major complication rate was 7%.  Crankshaft phenomenon observed in 3 Group A patients (21%); in these cases anterior arthrodesis was performed after a mean 15 mos period from first surgical procedure.  Fusion failure observed in 1 Group B patient, treated by revision of posterior instrumentation.  Clinical and radiographic evaluation at follow up showed good outcome in terms of deformity progression and quality of life. Results

7. Patient M. M. Female 21-07-1996 2004, age 8  right convex thoracic scoliosis with hyperkyphosis  highly dystrophic

8. Patient M. B. Female 21-07-1996 2005, age 9 Combined anterior and posterior arthrodesis with autologus bone graft

9. 2009, age 13 4-year follow-up Patient M. M. Female 21-07-1996 2011, age 15 6-year follow-up

10. In highly dystrophic progressive deformities in pediatric age:  early arthrodesis should be performed early  approach should be aggressive (anterior and posterior fusion) Posterior accessAnterior access Conclusions

11.  Surgical treatment of early progressive spinal deformities in NF1 is a demanding procedure with un uncertain outcome  Revision surgery may be necessary due to the ongoing dystrophic alterations that may occur over time (modulation). Conclusions 13-year-old male: double-access arthrodesis with anterior fibular graft 21 years follow up: erosion spares only anterior bone graft

12. None of the authors has any potential conflict of interest