The effect of simultaneous dual-rod derotation technique on thoracal kyphosis in patients with adolescent idiopathic scoliosis

Abstract

Aim:: When correcting the coronal plane deformity, providing thoracic kyphosis is also very important in scoliosis. The aim of our study is to determine the effect of the simultaneous dual-rod rotation technique(SDRT) on thoracic kyphosis of patients. Material and Methods: 23 patients with Aolescent Idiopathic Scoliosis (AIS) who underwent posterior spinal fusion and correction with the SDRT method in our clinic between August 2011 and September 2017 were included in the study. Demographic information of patients, Lenke classification, preoperative, second year and last follow up Cobb angles(PT, MT, T/L), apical vertebral rotation, thoracic kyphosis(T5-T12), C7 translation(coronal balance parameter) and sagittal vertical axis(SVA) measured. Results: The mean age of the patients was 14.4 years, the Female:Male ratio was 2.8:1, and the mean follow-up period was 4.24(4-10) years . Of them, 47%(n=10) of the patients had Lenke type 1, 26%(n=6) type 5, 17%(n=4) type3, 13%(n=3) had type 6 curve. The mean MT major curve was 44.3±3.2 degrees preoperatively, and 9.5±2.3 degrees and 12.3±3.6 degrees at the second year and last follow up. The mean major TL curvature was 54.3±2.9 degrees preoperatively, 7.4±5.1 degrees in the second year postoperatively, and 10.2±5.6 degrees at the last follow-up. The mean thoracic kyphosis was 29.6±4.8 degrees preoperatively, 26.4±4.3 degrees in the second year postoperatively, and 28.4±4.5 degrees at the last follow-up, while no statistically significant change was detected(p>0.05). The preoperative median value of C7 translation was 2.24 mm, 2.83 mm and 1.32 mm at the second year and at the last follow-up, respectively. While the mean preoperative value of SVA was -1.93 mm, it was -2.81 mm and -3.82 mm at the second year and at the last follow-up, respectively. The change in apical rotation was 1.8 before surgery and 1.6 there after. Conclusion: SDRT provides adequate improvement in the coronal plane, but has no significant corrective effect on thoracic kyphosis.

Keywords

• Scoliosis
• idiopathic
• adolescent
• kyphosis

Adölesan idiopatik skolyozlu hastalarda uygulanan eş zamanlı çift rod rotasyon tekniğinin torakal kifoza etkisi

Abstract

Amaç: Skolyoz, da koronal plan deformitesinin düzetilmesi kadar, torakal kifozun sağlanması da önemlidir. Çalışmamızın amacı, kliniğimizde uygulanan eş zamanlı dual-rod rotasyon tekniğinin (EDRT), torakal kifoz üzerine etkisinin tespit edilmesidir. Gereç ve Yöntemler: Kliniğimizde, Ağustos 2011-Eylül 2017 arasında EDRT ile düzeltme uygulanan ve posterior spinal füzyon yapılan 23 Adölesan İdiopatik Skolyoz (AİS) hastası çalışmaya dahil edildi. Hastaların demografik bilgileri, Lenke sınıflaması, ameliyat öncesi, 2. yıl ve son kontrol Cobb açıları (PT, MT, T/L), torakal kifozu (T5-T12), apikal vertebral rotasyon derecesi, C7 translasyonu (koronal denge parametresi) ve sagittal vertikal aksı (SVA) ölçüldü. Bulgular: Hastaların ortalama yaşı 14.4, Kadın:Erkek oranı 2.8:1, ortalama takip süresi 4.24 yıl (4-10 yıl) olarak bulundu. Hastaların %47’si (n=10) Lenke tip 1, %26’sı (n=6) tip 5, %17’si (n=4) tip 3, %13’ü (n=3) tip 6 eğriliğe sahipti. MT eğrilik ameliyat öncesi ortalama 44.3±3,2 derece, ameliyat sonrası ikinci yıl 9.5±2,3 derece ve son kontrolde 12.3±3,6 dereceydi. TL eğrilik ise ameliyat öncesi ortalama 54.3±2,9 derece, ameliyat sonrası ikinci yıl 7,4±5,1 derece ve son kontrolde 10,2±5,6 dereceydi. Torakal kifoz ameliyat öncesi ortalama 29.6±4,8 derece, ameliyat sonrası ikinci yıl 26.4±4,3 derece ve son kontrolde 28.4±4,5 dereceydi ve anlamlı değişiklik saptanmadı (p>0.05). C7 translasyonunun preop ortanca değeri 2,24 mm’yken, ikinci yıl ve son kontrolde sırasıyla 2,83 mm ve 1,32 mm; SVA’ın preop ortalama değeri -1,93 mm iken, ikinci yıl ve son kontrolde sırasıyla -2,81 mm ve -3,82 mm olarak bulundu. Apikal rotasyondaki değişim ise ameliyat öncesi 1,8 iken sonrası 1,6 olarak sabit kaldı. Sonuç: EDRT koronal planda yeterince düzelme sağlamaktadır ancak torakal kifoza anlamlı etkisisi yoktur.

Keywords

• Skolyoz
• idiopatik
• adölesan
• dual-rod derotasyon
• kifoz

References

1. 1. Cobb JR. American Academy of Orthopaedic Surgeons, ed Instructional Course Lectures. Vol. 5. Ann Arbor, MI: JW Edwards; 1948. Outline for the study of scoliosis; pp. 261–75
2. 2. Burwell RG. Aetilogy of idiopathic scoliosis: Current concepts. Pediatr Rehabil. 2003; 6: 137–70.
3. 3. Castelein RM, van Dieen JH, Smit TH. The role of dorsal shear forces in the pathogenesis of adolescent idiopathic scoliosis-a hypothesis. Med Hypotheses. 2005; 65: 501–8.
4. 4. Anekstein Y, Mirovsky Y, Arnabitsky V, et al. Reversing the concept: Correction of adolescent idiopathic scoliosis using the convex rod de-rotation maneuver. Eur Spine J 2012; 21: 1942-9.
5. 5. Kim YJ, Lenke LG, Bridwell KH, et al. Free hand pedicle screw placement in the thoracic spine. Is it safe? Spine 2004; 29: 333–42.
6. 6. Hwang SW, Samdani AF, Gressot LV, et al. Effect of direct vertebral body derotation on the sagittal profile in adolescent idiopathic scoliosis. Eur Spine J 2012; 21: 31–9.
7. 7. Delikaris A, Wang X, Boyer L, et al. Implant Density at the Apex Is More Important Than Overall Implant Density for 3D Correction in Thoracic Adolescent Idiopathic Scoliosis Using Rod Derotation and En Bloc Vertebral Derotation Technique. Spine 2018; 43: 639-47.
8. 8. Cotrel Y, Dubousset J, Guillaumat M. New universal instrumentation in spinal surgery. Clin Orthop. 1988; 227: 10-23.

9. 9. Liljenqvist UR, Halm HF, Link TM. Pedicle screw instrumentation of the thoracic spine in idiopathic scoliosis. Spine. 1997; 22: 2239-45
10. 10. Xiong B, Sevastik B, Willers U, et al. Structural vertebral changes in the horizontal plane in idiopathic scoliosis and the long-term corrective effect of spine instrumentation. Eur Spine J. 1995; 4: 11-4.
11. 11. Zifang H, Hengwei F, Yaolong D, et al. Convex-Rod Derotation Maneuver on Lenke Type I Adolescent Idiopathic Scoliosis. Neurosurgery. 2017; 81: 844-51.