A randomized double-blinded clinical trial to evaluate the safety and efficacy of a novel superelastic nickel–titanium spinal rod in adolescent idiopathic scoliosis: 5-year follow-up

  • Jason Pui Yin Cheung
  • Dino Samartzis
  • Kelvin Yeung
  • Michael To
  • Keith Dip Kei Luk
  • Kenneth Man-Chee Cheung
Original Article

Abstract

Purpose

To evaluate the safety and efficacy of a superelastic shape-memory alloy (SNT) rod used in the treatment of adolescent idiopathic scoliosis (AIS).

Methods

AIS Patients with Lenke 1 curves undergoing fusion surgery were randomized (1:1) at the time of surgery to receive either the SNT or a conventional titanium alloy (CTA) rod. Radiographs were obtained preoperatively and postoperatively up to 5 years of follow-up. Parameters assessed included coronal and sagittal Cobb angles, and overall truncal and shoulder balance. Sagittal profiles were subcategorized into Types A (<20°), B (20–40°), and C (>40°).

Results

Twenty-four patients with mean age of 15 years were recruited. A total of 87.0% of subjects were followed up till postoperative 5 years, but all patients had minimum 2 years of follow-up. The fulcrum-bending correction index for the SNT group was 113% at postoperative day 4 and 127% at half-year, while the CTA group was 112% at postoperative day 4 and only 106% at half-year. In terms of sagittal profile, the SNT group moved toward type B profile at half-year follow-up with a mean correction of 7.6°, while no significant change was observed in the CTA group (−0.7°). Nickel levels remained normal, and there were no complications.

Conclusions

This is the first randomized clinical trial of a novel SNT rod for treating patients with AIS, noting it to be safe and has potential to gradually correct scoliosis over time. This study serves as a pilot and platform to properly power future large-scale studies to demonstrate efficacy and superiority.

Keywords

Adolescent idiopathic scoliosis Superelastic Nickel Titanium Rod 

References

  1. 1.
    Lenke LG, White DK, Kemp JS, Bridwell KH, Blanke KM, Engsberg JR (2002) Evaluation of ventilatory efficiency during exercise in patients with idiopathic scoliosis undergoing spinal fusion. Spine (Phila Pa 1976) 27:2041–2045CrossRefGoogle Scholar
  2. 2.
    Luk KD, Lu DS, Cheung KM, Wong YW (2004) A prospective comparison of the coronal deformity correction in thoracic scoliosis using four different instrumentations and the fulcrum-bending radiograph. Spine (Phila Pa 1976) 29:560–563CrossRefGoogle Scholar
  3. 3.
    Cui G, Watanabe K, Nishiwaki Y, Hosogane N, Tsuji T, Ishii K, Nakamura M, Toyama Y, Chiba K, Matsumoto M (2012) Loss of apical vertebral derotation in adolescent idiopathic scoliosis: 2-year follow-up using multi-planar reconstruction computed tomography. Eur Spine J 21:1111–1120CrossRefPubMedPubMedCentralGoogle Scholar
  4. 4.
    Hwang SW, Samdani AF, Stanton P, Marks MC, Bastrom T, Newton PO, Betz RR, Cahill PJ (2013) Impact of pedicle screw fixation on loss of deformity correction in patients with adolescent idiopathic scoliosis. J Pediatr Orthop 33:377–382CrossRefPubMedGoogle Scholar
  5. 5.
    Takahashi J, Ikegami S, Kuraishi S, Shimizu M, Futatsugi T, Kato H (2014) Skip pedicle screw fixation combined with Ponte osteotomy for adolescent idiopathic scoliosis. Eur Spine J 23:2689–2695CrossRefPubMedGoogle Scholar
  6. 6.
    Yilmaz G, Borkhuu B, Dhawale AA, Oto M, Littleton AG, Mason DE, Gabos PG, Shah SA (2012) Comparative analysis of hook, hybrid, and pedicle screw instrumentation in the posterior treatment of adolescent idiopathic scoliosis. J Pediatr Orthop 32:490–499CrossRefPubMedGoogle Scholar
  7. 7.
    Cheng I, Kim Y, Gupta MC, Bridwell KH, Hurford RK, Lee SS, Theerajunyaporn T, Lenke LG (2005) Apical sublaminar wires versus pedicle screws–which provides better results for surgical correction of adolescent idiopathic scoliosis? Spine (Phila Pa 1976) 30:2104–2112CrossRefGoogle Scholar
  8. 8.
    Kim YJ, Lenke LG, Cho SK, Bridwell KH, Sides B, Blanke K (2004) Comparative analysis of pedicle screw versus hook instrumentation in posterior spinal fusion of adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 29:2040–2048CrossRefGoogle Scholar
  9. 9.
    Kim YJ, Lenke LG, Kim J, Bridwell KH, Cho SK, Cheh G, Sides B (2006) Comparative analysis of pedicle screw versus hybrid instrumentation in posterior spinal fusion of adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 31:291–298CrossRefGoogle Scholar
  10. 10.
    Remes V, Helenius I, Schlenzka D, Yrjonen T, Ylikoski M, Poussa M (2004) Cotrel-Dubousset (CD) or Universal Spine System (USS) instrumentation in adolescent idiopathic scoliosis (AIS): comparison of midterm clinical, functional, and radiologic outcomes. Spine (Phila Pa 1976) 29:2024–2030CrossRefGoogle Scholar
  11. 11.
    Suk SI, Lee SM, Chung ER, Kim JH, Kim SS (2005) Selective thoracic fusion with segmental pedicle screw fixation in the treatment of thoracic idiopathic scoliosis: more than 5-year follow-up. Spine (Phila Pa 1976) 30:1602–1609CrossRefGoogle Scholar
  12. 12.
    Cidambi KR, Glaser DA, Bastrom TP, Nunn TN, Ono T, Newton PO (2012) Postoperative changes in spinal rod contour in adolescent idiopathic scoliosis: an in vivo deformation study. Spine (Phila Pa 1976) 37:1566–1572CrossRefGoogle Scholar
  13. 13.
    Serhan H, Mhatre D, Newton P, Giorgio P, Sturm P (2013) Would CoCr rods provide better correctional forces than stainless steel or titanium for rigid scoliosis curves? J Spinal Disord Tech 26:E70–74CrossRefPubMedGoogle Scholar
  14. 14.
    Abul-Kasim K, Karlsson MK, Ohlin A (2011) Increased rod stiffness improves the degree of deformity correction by segmental pedicle screw fixation in adolescent idiopathic scoliosis. Scoliosis 6:13CrossRefPubMedPubMedCentralGoogle Scholar
  15. 15.
    Huang TH, Ma HL, Wang ST, Chou PH, Ying SH, Liu CL, Yu WK, Chang MC (2014) Does the size of the rod affect the surgical results in adolescent idiopathic scoliosis? 5.5-mm versus 6.35-mm rod. Spine J 14:1545–1550CrossRefPubMedGoogle Scholar
  16. 16.
    Prince DE, Matsumoto H, Chan CM, Gomez JA, Hyman JE, Roye DP Jr, Vitale MG (2014) The effect of rod diameter on correction of adolescent idiopathic scoliosis at two years follow-up. J Pediatr Orthop 34:22–28CrossRefPubMedGoogle Scholar
  17. 17.
    Clements DH, Betz RR, Newton PO, Rohmiller M, Marks MC, Bastrom T (2009) Correlation of scoliosis curve correction with the number and type of fixation anchors. Spine (Phila Pa 1976) 34:2147–2150CrossRefGoogle Scholar
  18. 18.
    Hwang CJ, Lee CK, Chang BS, Kim MS, Yeom JS, Choi JM (2011) Minimum 5-year follow-up results of skipped pedicle screw fixation for flexible idiopathic scoliosis. J Neurosurg Spine 15:146–150CrossRefPubMedGoogle Scholar
  19. 19.
    Bharucha NJ, Lonner BS, Auerbach JD, Kean KE, Trobisch PD (2013) Low-density versus high-density thoracic pedicle screw constructs in adolescent idiopathic scoliosis: do more screws lead to a better outcome? Spine J 13:375–381CrossRefPubMedGoogle Scholar
  20. 20.
    Liu H, Li Z, Li S, Zhang K, Yang H, Wang J, Li X, Zheng Z (2014) Main thoracic curve adolescent idiopathic scoliosis: association of higher rod stiffness and concave-side pedicle screw density with improvement in sagittal thoracic kyphosis restoration. J Neurosurg Spine 22:1–8Google Scholar
  21. 21.
    Giudici F, Galbusera F, Zagra A, Wilke H-J, Archetti M, Scaramuzzo L (2017) Determinants of the biomechanical and radiological outcome of surgical correction of adolescent idiopathic scoliosis surgery: the role of rod properties and patient characteristics. Eur Spine J. doi:10.1007/s00586-017-5148-x Google Scholar
  22. 22.
    Yoshihara H (2013) Rods in spinal surgery: a review of the literature. Spine J Off J N Am Spine Soc 13:1350–1358CrossRefGoogle Scholar
  23. 23.
    Hwang SW, Samdani AF, Tantorski M, Cahill P, Nydick J, Fine A, Betz RR, Antonacci MD (2011) Cervical sagittal plane decompensation after surgery for adolescent idiopathic scoliosis: an effect imparted by postoperative thoracic hypokyphosis. J Neurosurg Spine 15:491–496CrossRefPubMedGoogle Scholar
  24. 24.
    Ilharreborde B, Morel E, Mazda K, Dekutoski MB (2009) Adjacent segment disease after instrumented fusion for idiopathic scoliosis: review of current trends and controversies. J Spinal Disord Tech 22:530–539CrossRefPubMedGoogle Scholar
  25. 25.
    Schlosser TP, Shah SA, Reichard SJ, Rogers K, Vincken KL, Castelein RM (2014) Differences in early sagittal plane alignment between thoracic and lumbar adolescent idiopathic scoliosis. Spine J 14:282–290CrossRefPubMedGoogle Scholar
  26. 26.
    Yong Q, Zhen L, Zezhang Z, Bangping Q, Feng Z, Tao W, Jun J, Xu S, Xusheng Q, Weiwei M, Weijun W (2012) Comparison of sagittal spinopelvic alignment in Chinese adolescents with and without idiopathic thoracic scoliosis. Spine (Phila Pa 1976) 37:E714–E720CrossRefGoogle Scholar
  27. 27.
    Luhmann SJ, Lenke LG, Erickson M, Bridwell KH, Richards BS (2012) Correction of moderate (< 70 degrees) Lenke 1A and 2A curve patterns: comparison of hybrid and all-pedicle screw systems at 2-year follow-up. J Pediatr Orthop 32:253–258CrossRefPubMedGoogle Scholar
  28. 28.
    Newton PO, Yaszay B, Upasani VV, Pawelek JB, Bastrom TP, Lenke LG, Lowe T, Crawford A, Betz R, Lonner B, Harms Study G (2010) Preservation of thoracic kyphosis is critical to maintain lumbar lordosis in the surgical treatment of adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 35:1365–1370CrossRefGoogle Scholar
  29. 29.
    Potter BK, Lenke LG, Kuklo TR (2004) Prevention and management of iatrogenic flatback deformity. J Bone Jt Surg Am 86-A:1793–1808CrossRefGoogle Scholar
  30. 30.
    Watanabe K, Nakamura T, Iwanami A, Hosogane N, Tsuji T, Ishii K, Nakamura M, Toyama Y, Chiba K, Matsumoto M (2012) Vertebral derotation in adolescent idiopathic scoliosis causes hypokyphosis of the thoracic spine. BMC Musculoskelet Disord 13:99CrossRefPubMedPubMedCentralGoogle Scholar
  31. 31.
    Belmont PJ Jr, Klemme WR, Dhawan A, Polly DW Jr (2001) In vivo accuracy of thoracic pedicle screws. Spine (Phila Pa 1976) 26:2340–2346CrossRefGoogle Scholar
  32. 32.
    Lehman RA Jr, Lenke LG, Keeler KA, Kim YJ, Buchowski JM, Cheh G, Kuhns CA, Bridwell KH (2008) Operative treatment of adolescent idiopathic scoliosis with posterior pedicle screw-only constructs: minimum three-year follow-up of one hundred fourteen cases. Spine (Phila Pa 1976) 33:1598–1604CrossRefGoogle Scholar
  33. 33.
    Suk SI, Kim WJ, Lee SM, Kim JH, Chung ER (2001) Thoracic pedicle screw fixation in spinal deformities: are they really safe? Spine (Phila Pa 1976) 26:2049–2057CrossRefGoogle Scholar
  34. 34.
    Yeung KW, Cheung KMC, Lu WW, Chung CY (2004) Optimization of thermal treatment parameters to alter austenitic phase transition temperature of NiTi alloy for medical implant. Mater Sci Eng, A 383:213–218CrossRefGoogle Scholar
  35. 35.
    Kim YJ, Kassab F, Berven SH, Zurakowski D, Hresko MT, Emans JB, Kasser JR (2005) Serum levels of nickel and chromium after instrumented posterior spinal arthrodesis. Spine (Phila Pa 1976) 30:923–926CrossRefGoogle Scholar
  36. 36.
    Liu X, Wu S, Yeung KW, Chan YL, Hu T, Xu Z, Liu X, Chung JC, Cheung KM, Chu PK (2011) Relationship between osseointegration and superelastic biomechanics in porous NiTi scaffolds. Biomaterials 32:330–338CrossRefPubMedGoogle Scholar
  37. 37.
    Liu XM, Wu SL, Chan YL, Chu PK, Chung CY, Chu CL, Yeung KW, Lu WW, Cheung KM, Luk KD (2007) Surface characteristics, biocompatibility, and mechanical properties of nickel–titanium plasma-implanted with nitrogen at different implantation voltages. J Biomed Mater Res A 82:469–478CrossRefPubMedGoogle Scholar
  38. 38.
    Poon RW, Yeung KW, Liu XY, Chu PK, Chung CY, Lu WW, Cheung KM, Chan D (2005) Carbon plasma immersion ion implantation of nickel–titanium shape memory alloys. Biomaterials 26:2265–2272CrossRefPubMedGoogle Scholar
  39. 39.
    Wu S, Liu X, Chan YL, Chu PK, Chung CY, Chu C, Yeung KW, Lu WW, Cheung KM, Luk KD (2009) Nickel release behavior and surface characteristics of porous NiTi shape memory alloy modified by different chemical processes. J Biomed Mater Res A 89:483–489CrossRefPubMedGoogle Scholar
  40. 40.
    Wu S, Liu X, Chan YL, Ho JP, Chung CY, Chu PK, Chu CL, Yeung KW, Lu WW, Cheung KM, Luk KD (2007) Nickel release behavior, cytocompatibility, and superelasticity of oxidized porous single-phase NiTi. J Biomed Mater Res A 81:948–955CrossRefPubMedGoogle Scholar
  41. 41.
    Wu SL, Chu PK, Liu XM, Chung CY, Ho JP, Chu CL, Tjong SC, Yeung KW, Lu WW, Cheung KM, Luk KD (2006) Surface characteristics, mechanical properties, and cytocompatibility of oxygen plasma-implanted porous nickel titanium shape memory alloy. J Biomed Mater Res A 79:139–146CrossRefPubMedGoogle Scholar
  42. 42.
    Yeung KW, Lu WW, Luk KD, Cheung KM (2006) Mechanical testing of a smart spinal implant locking mechanism based on nickel–titanium alloy. Spine (Phila Pa 1976) 31:2296–2303CrossRefGoogle Scholar
  43. 43.
    Yeung KW, Poon RW, Chu PK, Chung CY, Liu XY, Lu WW, Chan D, Chan SC, Luk KD, Cheung KM (2007) Surface mechanical properties, corrosion resistance, and cytocompatibility of nitrogen plasma-implanted nickel–titanium alloys: a comparative study with commonly used medical grade materials. J Biomed Mater Res A 82:403–414CrossRefPubMedGoogle Scholar
  44. 44.
    Yeung KW, Poon RW, Liu XY, Ho JP, Chung CY, Chu PK, Lu WW, Chan D, Cheung KM (2005) Corrosion resistance, surface mechanical properties, and cytocompatibility of plasma immersion ion implantation-treated nickel–titanium shape memory alloys. J Biomed Mater Res A 75:256–267CrossRefPubMedGoogle Scholar
  45. 45.
    Yeung KW, Poon RW, Liu XY, Ho JP, Chung CY, Chu PK, Lu WW, Chan D, Cheung KM (2005) Investigation of nickel suppression and cytocompatibility of surface-treated nickel–titanium shape memory alloys by using plasma immersion ion implantation. J Biomed Mater Res A 72:238–245CrossRefPubMedGoogle Scholar
  46. 46.
    de Jonge T, Dubousset JF, Illes T (2002) Sagittal plane correction in idiopathic scoliosis. Spine (Phila Pa 1976) 27:754–760CrossRefGoogle Scholar
  47. 47.
    Cheung KM, Luk KD (1997) Prediction of correction of scoliosis with use of the fulcrum bending radiograph. J Bone Jt Surg Am 79:1144–1150CrossRefGoogle Scholar
  48. 48.
    Cheung KM, Natarajan D, Samartzis D, Wong YW, Cheung WY, Luk KD (2010) Predictability of the fulcrum bending radiograph in scoliosis correction with alternate-level pedicle screw fixation. J Bone Jt Surg Am 92:169–176CrossRefGoogle Scholar
  49. 49.
    Luk KD, Cheung KM, Lu DS, Leong JC (1998) Assessment of scoliosis correction in relation to flexibility using the fulcrum bending correction index. Spine (Phila Pa 1976) 23:2303–2307CrossRefGoogle Scholar
  50. 50.
    Samartzis D, Leung Y, Shigematsu H, Natarajan D, Stokes O, Mak KC, Yao G, Luk KD, Cheung KM (2015) Selection of fusion levels using the fulcrum bending radiograph for the management of adolescent idiopathic scoliosis patients with alternate level pedicle screw strategy: clinical decision-making and outcomes. PLoS One 10:e0120302CrossRefPubMedPubMedCentralGoogle Scholar
  51. 51.
    Shigematsu H, Cheung JP, Bruzzone M, Matsumori H, Mak KC, Samartzis D, Luk KD (2017) Preventing fusion mass shift avoids postoperative distal curve adding-on in adolescent idiopathic scoliosis. Clin Orthop Relat Res 475:1448–1460CrossRefPubMedGoogle Scholar
  52. 52.
    Yao G, Cheung JP, Shigematsu H, Ohrt-Nissen S, Cheung KM, Luk KD, Samartzis D (2016) Characterization and predictive Value of “Segmental Curve Flexibility” in adolescent idiopathic scoliosis patients. Spine (Phila Pa 1976) (In Press)Google Scholar
  53. 53.
    Luk KD, Vidyadhara S, Lu DS, Wong YW, Cheung WY, Cheung KM (2010) Coupling between sagittal and frontal plane deformity correction in idiopathic thoracic scoliosis and its relationship with postoperative sagittal alignment. Spine (Phila Pa 1976) 35:1158–1164CrossRefGoogle Scholar
  54. 54.
    Stagnara P, De Mauroy JC, Dran G, Gonon GP, Costanzo G, Dimnet J, Pasquet A (1982) Reciprocal angulation of vertebral bodies in a sagittal plane: approach to references for the evaluation of kyphosis and lordosis. Spine (Phila Pa 1976) 7:335–342CrossRefGoogle Scholar
  55. 55.
    Ilizarov GA (1988) The principles of the Ilizarov method. Bull Hosp Jt Dis Orthop Inst 48:1–11PubMedGoogle Scholar
  56. 56.
    Cheung JP, Samartzis D, Cheung KM (2014) A novel approach to gradual correction of severe spinal deformity in a pediatric patient using the magnetically-controlled growing rod. Spine J 14:e7–13CrossRefPubMedGoogle Scholar
  57. 57.
    Sanders JO, Sanders AE, More R, Ashman RB (1993) A preliminary investigation of shape memory alloys in the surgical correction of scoliosis. Spine (Phila Pa 1976) 18:1640–1646CrossRefGoogle Scholar
  58. 58.
    Wang Y, Zheng G, Zhang X, Zhang Y, Xiao S, Wang Z (2010) Comparative analysis between shape memory alloy-based correction and traditional correction technique in pedicle screws constructs for treating severe scoliosis. Eur Spine J 19:394–399CrossRefPubMedGoogle Scholar
  59. 59.
    Wang Y, Zheng G, Zhang X, Zhang Y, Xiao S, Wang Z (2011) Temporary use of shape memory spinal rod in the treatment of scoliosis. Eur Spine J 20:118–122CrossRefPubMedGoogle Scholar
  60. 60.
    Lowenstein JE, Matsumoto H, Vitale MG, Weidenbaum M, Gomez JA, Lee FY, Hyman JE, Roye DP Jr (2007) Coronal and sagittal plane correction in adolescent idiopathic scoliosis: a comparison between all pedicle screw versus hybrid thoracic hook lumbar screw constructs. Spine (Phila Pa 1976) 32:448–452CrossRefGoogle Scholar
  61. 61.
    Vora V, Crawford A, Babekhir N, Boachie-Adjei O, Lenke L, Peskin M, Charles G, Kim Y (2007) A pedicle screw construct gives an enhanced posterior correction of adolescent idiopathic scoliosis when compared with other constructs: myth or reality. Spine (Phila Pa 1976) 32:1869–1874CrossRefGoogle Scholar
  62. 62.
    Carreon LY, Sanders JO, Diab M, Sturm PF, Sucato DJ, Spinal Deformity Study G (2011) Patient satisfaction after surgical correction of adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 36:965–968CrossRefGoogle Scholar
  63. 63.
    Cundy TP, Antoniou G, Sutherland LM, Freeman BJ, Cundy PJ (2013) Serum titanium, niobium, and aluminum levels after instrumented spinal arthrodesis in children. Spine (Phila Pa 1976) 38:564–570CrossRefGoogle Scholar
  64. 64.
    Putters JL, Kaulesar Sukul DM, de Zeeuw GR, Bijma A, Besselink PA (1992) Comparative cell culture effects of shape memory metal (Nitinol), nickel and titanium: a biocompatibility estimation. Eur Surg Res 24:378–382CrossRefPubMedGoogle Scholar
  65. 65.
    Doran A, Law FC, Allen MJ, Rushton N (1998) Neoplastic transformation of cells by soluble but not particulate forms of metals used in orthopaedic implants. Biomaterials 19:751–759CrossRefPubMedGoogle Scholar
  66. 66.
    Kujala S, Pajala A, Kallioinen M, Pramila A, Tuukkanen J, Ryhanen J (2004) Biocompatibility and strength properties of nitinol shape memory alloy suture in rabbit tendon. Biomaterials 25:353–358CrossRefPubMedGoogle Scholar
  67. 67.
  68. 68.
    Zhu F, Fan W, Wang X, Qu L, Yao S (2011) Health risk assessment of eight heavy metals in nine varieties of edible vegetable oils consumed in China. Food Chem Toxicol 49:3081–3085CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Department of Orthopaedics and TraumatologyThe University of Hong KongHong Kong SARChina

Personalised recommendations