Biomechanical in vitro comparison between anterior column realignment and pedicle subtraction osteotomy for severe sagittal imbalance correction
To investigate the biomechanical effects of anterior column realignment (ACR) and pedicle subtraction osteotomy (PSO) on local lordosis correction, primary stability and rod strains.
Seven cadaveric spine segments (T12–S1) underwent ACR at L1–L2. A stand-alone hyperlordotic cage was initially tested and then supplemented with posterior bilateral fixation. The same specimens already underwent a PSO at L4 stabilized by two rods, a supplemental central rod (three rods) and accessory rods (four rods) with and without adjacent interbody cages (La Barbera in Eur Spine J 27(9):2357–2366, 2018). In vitro flexibility tests were performed under pure moments in flexion/extension (FE), lateral bending (LB) and axial rotation (AR) to determine the range of motion (RoM), while measuring the rod strains with strain gauge rosettes.
Local lordosis correction with ACR (24.7° ± 3.7°) and PSO (25.1° ± 3.9°) was similar. Bilateral fixation significantly reduced the RoM (FE: 31%, LB: 2%, AR: 18%), providing a stability consistent with PSO constructs (p > 0.05); however, it demonstrates significantly higher rod strains compared to PSO constructs with lateral accessory rods and interbody cages in FE and AR (p < 0.05), while being comparable in FE or slightly higher in AR compared to PSO constructs with two and three rods.
Bilateral posterior fixation is highly recommended following ACR to provide adequate primary stability. However, primary rod strains in ACR were found comparable or higher than weak PSO construct associated with frequent rod failure; therefore, caution is recommended.
KeywordsAnterior column release Pedicle subtraction osteotomy Primary stability Revision surgery Rod breakage In vitro study Strain gauge Spine Biomechanics
The study was funded by the Scoliosis Research Society through a New Investigator Grant awarded to the first author. The implants and surgical tools for specimens’ preparation and instrumentation were provided by DePuy Synthes (Raynham, MA, USA), Medtronic Sofamor Danek (Minneapolis, MN, USA) and NuVasive (San Diego, CA, USA). The authors gratefully acknowledge Gloria Casaroli Ph.D., Maria Luisa Ruspi, Lisa Flachmüller and Theodor Di Pauli von Treuheim for their assistance during specimens’ preparation.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest related to the content of the current study.
- 3.Smith JS, Shaffrey CI, Glassman SD, Berven SH, Schwab FJ, Hamill CL, Horton WC, Ondra SL, Sansur CA, Bridwell KH, Spinal Deformity Study Group (2011) Risk-benefit assessment of surgery for adult scoliosis: an analysis based on patient age. Spine (Phila Pa 1976) 36(10):817–824. https://doi.org/10.1097/BRS.0b013e3181e21783 CrossRefGoogle Scholar
- 5.La Barbera L, Brayda-Bruno M, Liebsch C, Villa T, Luca A, Galbusera F, Wilke HJ (2018) Biomechanical advantages of supplemental accessory and satellite rods with and without interbody cages implantation for the stabilization of pedicle subtraction osteotomy. Eur Spine J 27(9):2357–2366. https://doi.org/10.1007/s00586-018-5623-z CrossRefGoogle Scholar
- 6.Smith JS, Shaffrey CI, Klineberg E et al (2017) Complication rates associated with 3-column osteotomy in 82 adult spinal deformity patients: retrospective review of a prospectively collected multicenter consecutive series with 2-year follow-up. J Neurosurg Spine 27(4):444–457. https://doi.org/10.3171/2016.10.SPINE16849 CrossRefGoogle Scholar
- 8.Smith JS, Shaffrey CI, Ames CP, Demakakos J, Fu KMG, Keshavarzi S, Li CMY, Deviren V, Schwab FJ, Lafage V, Bess S (2012) Assessment of symptomatic rod fracture after posterior instrumented fusion for adult spinal deformity. Neurosurgery 71(4):862–867. https://doi.org/10.1227/NEU.0b013e3182672aab CrossRefGoogle Scholar
- 10.Gupta S, Eksi MS, Ames CP, Deviren V, Durbin-Johnson B, Smith JS, Gupta MC (2017) A novel 4-rod technique offers potential to reduce rod breakage and pseudarthrosis in pedicle subtraction osteotomies for adult spinal deformity correction. Oper Neurosurg (Hagerstown). https://doi.org/10.1093/ons/opx151 Google Scholar
- 14.Uribe JS, Schwab F, Mundis GM, Xu DS, Januszewski J, Kanter AS, Okonkwo DO, Hu SS, Vedat D, Eastlack R, Berjano P, Mummaneni PV (2019) The comprehensive anatomical spinal osteotomy and anterior column realignment classification. J Neurosurg Spine 29(5):565–575. https://doi.org/10.3171/2018.4.SPINE171206 CrossRefGoogle Scholar
- 16.Deukmedjian AR, Dakwar E, Ahmadian A, Smith DA, Uribe JS (2012) Early outcomes of minimally invasive anterior longitudinal ligament release for correction of sagittal imbalance in patients with adult spinal deformity. Sci World J 2012:789698. https://doi.org/10.1100/2012/789698 CrossRefGoogle Scholar
- 17.Mundis GM Jr, Turner JD, Kabirian N, Pawelek J, Eastlack RK, Uribe J, Klineberg E, Bess S, Ames C, Deviren V, Nguyen S, Lafage V, Akbarnia BA, International Spine Study Group (2017) Anterior column realignment has similar results to pedicle subtraction osteotomy in treating adults with sagittal plane deformity. World Neurosurg 105:249–256. https://doi.org/10.1016/j.wneu.2017.05.122 CrossRefGoogle Scholar
- 18.Deukmedjian AR, Le TV, Baaj AA, Dakwar E, Smith DA, Uribe JS (2012) Anterior longitudinal ligament release using the minimally invasive lateral retroperitoneal transpsoas approach: a cadaveric feasibility study and report of 4 clinical cases. J Neurosurg Spine 17(6):530539. https://doi.org/10.3171/2012.8.SPINE12432 CrossRefGoogle Scholar
- 19.Hosseini P, Mundis GM Jr, Eastlack RK, Bagheri R, Vargas E, Tran S, Akbarnia BA (2017) Preliminary results of anterior lumbar interbody fusion, anterior column realignment for the treatment of sagittal malalignment. Neurosurg Focus 43(6):E6. https://doi.org/10.3171/2017.8.FOCUS17423 CrossRefGoogle Scholar
- 20.Berjano P, Cecchinato R, Sinigaglia A, Damilano M, Ismael MF, Martini C, Villafañe JH, Lamartina C (2015) Anterior column realignment from a lateral approach for the treatment of severe sagittal imbalance: a retrospective radiographic study. Eur Spine J 24(Suppl 3):433–438. https://doi.org/10.1007/s00586-015-3930-1 CrossRefGoogle Scholar
- 21.Akbarnia BA, Mundis GM Jr, Moazzaz P, Kabirian N, Bagheri R, Eastlack RK, Pawelek JB (2014) Anterior column realignment (ACR) for focal kyphotic spinal deformity using a lateral transpsoas approach and ALL release. J Spinal Disord Tech 27(1):29–39. https://doi.org/10.1097/BSD.0b013e318287bdc1 CrossRefGoogle Scholar
- 22.Le TV, Baaj AA, Dakwar E, Burkett CJ, Murray G, Smith DA, Uribe JS (2012) Subsidence of polyetheretherketone intervertebral cages in minimally invasive lateral retroperitoneal transpsoas lumbar interbody fusion. Spine (Phila Pa 1976) 37(14):1268–1273. https://doi.org/10.1097/BRS.0b013e3182458b2f CrossRefGoogle Scholar
- 23.Luca A, Ottardi C, Sasso M, Prosdocimo L, La Barbera L, Brayda-Bruno M, Galbusera F, Villa T (2017) Instrumentation failure following pedicle subtraction osteotomy: the role of rod material, diameter, and multi-rod constructs. Eur Spine J 26(3):764–770. https://doi.org/10.1007/s00586-016-4859-8 CrossRefGoogle Scholar
- 24.Luca A, Ottardi C, Lovi A, Brayda-Bruno M, Villa T, Galbusera F (2017) Anterior support reduces the stresses on the posterior instrumentation after pedicle subtraction osteotomy: a finite-element study. Eur Spine J 26(Suppl 4):450–456. https://doi.org/10.1007/s00586-017-5084-9 CrossRefGoogle Scholar
- 25.Kim C, Harris JA, Muzumdar A, Khalil S, Sclafani JA, Raiszadeh K, Bucklen BS (2017) The effect of anterior longitudinal ligament resection on lordosis correction during minimally invasive lateral lumbar interbody fusion: biomechanical and radiographic feasibility of an integrated spacer/plate interbody reconstruction device. Clin Biomech (Bristol Avon) 43:102–108. https://doi.org/10.1016/j.clinbiomech.2017.02.006 CrossRefGoogle Scholar
- 26.Uribe JS, Smith DA, Dakwar E, Baaj AA, Mundis GM, Turner AW, Cornwall GB, Akbarnia BA (2012) Lordosis restoration after anterior longitudinal ligament release and placement of lateral hyperlordotic interbody cages during the minimally invasive lateral transpsoas approach: a radiographic study in cadavers. J Neurosurg Spine 17(5):476–485. https://doi.org/10.3171/2012.8.SPINE111121 CrossRefGoogle Scholar
- 27.Uribe JS, Harris JE, Beckman JM, Turner AW, Mundis GM, Akbarnia BA (2015) Finite element analysis of lordosis restoration with anterior longitudinal ligament release and lateral hyperlordotic cage placement. Eur Spine J 24(Suppl 3):420–426. https://doi.org/10.1007/s00586-015-3872-7 CrossRefGoogle Scholar
- 39.Lafage V, Schwab F, Vira S, Hart R, Burton D, Smith JS, Boachie-Adjei O, Shelokov A, Hostin R, Shaffrey CI, Gupta M, Akbarnia BA, Bess S, Farcy JP (2011) Does vertebral level of pedicle subtraction osteotomy correlate with degree of spinopelvic parameter correction? J Neurosurg Spine 14(2):184–191. https://doi.org/10.3171/2010.9.SPINE10129 CrossRefGoogle Scholar