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Cervical sagittal balance: a biomechanical perspective can help clinical practice

European Spine Journal volume 27, pages 25–38 (2018)Cite this article

Abstract

Purpose

In this article, we summarize our work on understanding the influence of cervical sagittal malalignment on the mechanics of the cervical spine.

Methods

Biomechanical studies were performed using an ex vivo laboratory model to study the kinematic and kinetic response of human cervical spine specimens in the setting of cervical sagittal imbalance. The model allowed controlled variations of C2–C7 Sagittal Vertical Alignment (C2–C7 SVA) and T1-Slope so that clinically relevant sagittally malaligned profiles could be prescribed, while maintaining horizontal gaze, and their biomechanical consequences studied.

Results

Our results demonstrated that increasing C2–C7 SVA caused flexion of lower cervical (C2–C7) segments and hyperextension of suboccipital (C0–C1–C2) segments to maintain horizontal gaze. An increase in C2–C7 SVA increased the lower cervical neural foraminal areas. Conversely, increasing T1-slope predominantly influenced subaxial cervical lordosis and, as a result, decreased cervical neural foraminal areas. Therefore, we believe patients with increased upper thoracic kyphosis and radicular symptoms may respond with increased forward head posture (FHP) as a compensatory mechanism to increase their lower cervical neural foraminal area and alleviate nerve root compression as well as reduce the burden on posterior muscles and soft and bony structures of the cervical spine. Increasing FHP (i.e., increased C2–C7 SVA) was associated with shortening of the cervical flexors and occipital extensors and lengthening of the cervical extensors and occipital flexors, which corresponds to C2–C7 flexion and C0–C2 extension. The greatest shortening occurred in the suboccipital muscles, suggesting considerable load bearing of these muscles during chronic FHP. Regardless, there was no evidence of nerve compression within the suboccipital triangle. Finally, cervical sagittal imbalance may play a role in exacerbating adjacent segment pathomechanics after multilevel cervical fusion and should be considered during surgical planning.

Conclusions

The results of our biomechanical studies have improved our understanding of the impact of cervical sagittal malalignment on pathomechanics of the cervical spine. We believe this improved understanding will assist in clinical decision-making.

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Note: Asterisks correspond to statistical significance: *P < 0.05, and **P < 0.01. Figures a and b are reprinted from Patwardhan et al. [19], Fig. c reprinted from Khayatzadeh et al. [21]

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References

  1. McAviney J, Schulz D, Bock R, Harrison DE, Holland B (2005) Determining the relationship between cervical lordosis and neck complaints. J Manip Physiol Ther 28:187–193

    Article  Google Scholar 

  2. Yip CH, Chiu TT, Poon AT (2008) May) The relationship between head posture and severity and disability of patients with neck pain. Man Ther 13:148–154

    Article  PubMed  Google Scholar 

  3. Lau KT, Cheung KY, Chan KB et al (2010) Oct) Relationships between sagittal postures of thoracic and cervical spine, presence of neck pain, neck pain severity and disability. Man Ther 15:457–462

    Article  PubMed  Google Scholar 

  4. Villavicencio AT, Babuska JM, Ashton A et al (2011) Prospective, randomized, double-blind clinical study evaluating the correlation of clinical outcomes and cervical sagittal alignment. Neurosurgery 68:1309–1316

    Article  PubMed  Google Scholar 

  5. Tang JA, Scheer JK, Smith JS et al (2012) The impact of standing regional cervical sagittal alignment on outcomes in posterior cervical fusion surgery. Neurosurgery 71:662–669

    Article  PubMed  Google Scholar 

  6. Smith JS, Shaffrey CI, Lafage V et al (2012) Spontaneous improvement of cervical alignment after correction of global sagittal balance following pedicle subtraction osteotomy. J Neurosurg Spine 17:300–307

    Article  PubMed  Google Scholar 

  7. Kuntz C, Levin LS, Ondra SL, Shaffrey CI, Morgan CJ (2007) Neutral upright sagittal spinal alignment from the occiput to the pelvis in asymptomatic adults: a review and resynthesis of the literature. J Neurosurg Spine 6:104–112

    Article  PubMed  Google Scholar 

  8. Iyer S, Nemani VM, Nguyen J et al (2016) Impact of cervical sagittal alignment parameters on neck disability. Spine 41:371–377

    Article  PubMed  Google Scholar 

  9. Hoy D, March L, Woolf A et al (2014) The global burden of neck pain: estimates from the global burden of disease 2010 study. Ann Rheum Dis 73:1309–1315

    Article  PubMed  Google Scholar 

  10. Bao H, Varghese J, Lafage R et al (2017) Principal radiographic characteristics for cervical spinal deformity: a health-related quality of life analysis. Spine 42(18):1375–1382

    Article  PubMed  Google Scholar 

  11. Scheer JK, Tang JA, Smith JS et al (2013) Cervical spine alignment, sagittal deformity, and clinical implications: a review. J Neurosurg Spine 19:141–159

    Article  PubMed  Google Scholar 

  12. Hardacker JW, Shuford RF, Capicotto PN, Pryor PW (1997) Radiographic standing cervical segmental alignment in adult volunteers without neck symptoms. Spine 22(13):1472–1479

    CAS  Article  PubMed  Google Scholar 

  13. Cacho-Rodrigues P, Campana M, Obeid I, Vital JM, Gille O (2016) Sagittal Correction and reciprocal changes after thoracic pedicle subtraction osteotomy. Spine 41(13):E791–E797

    Article  PubMed  Google Scholar 

  14. Knott PT, Mardjetko SM, Techy F (2010) The use of the T1 sagittal angle in predicting overall sagittal balance of the spine. Spine J 10:994–998

    Article  PubMed  Google Scholar 

  15. Bess S, Protopsaltis TS, Lafage V et al (2016) Clinical and radiographic evaluation of adult spinal deformity. Clin Spine Surg 29:6–16

    PubMed  Google Scholar 

  16. Lamartina C, Berjano P (2014) Jun) Classification of sagittal imbalance based on spinal alignment and compensatory mechanisms. Eur Spine J 23:1177–1189

    Article  PubMed  Google Scholar 

  17. Ames CP, Blondel B, Scheer JK et al (2013) Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy. Spine 38:S149–S160

    Article  PubMed  Google Scholar 

  18. Le Huec J-C, Demezon H, Aunoble S (2015) Sagittal parameters of global cervical balance using EOS imaging: normative values from a prospective cohort of asymptomatic volunteers. Eur Spine J 24:63–71

    Article  PubMed  Google Scholar 

  19. Patwardhan AG, Havey RM, Khayatzadeh S et al (2015) Postural consequences of cervical sagittal imbalance: a novel laboratory model. Spine 40:783–792

    Article  PubMed  Google Scholar 

  20. Smith ZA, Khayatzadeh S, Bakhsheshian J et al (2016) Dimensions of the cervical neural foramen in conditions of spinal deformity: an ex vivo biomechanical investigation using specimen-specific CT imaging. Eur Spine J 25:2155–2165

    Article  PubMed  Google Scholar 

  21. Khayatzadeh S, Kalmanson OA, Schuit D et al (2017) Cervical spine muscle-tendon unit length differences between neutral and forward head postures: biomechanical study using human cadaveric specimens. Phys Ther 97(7):756–766

    Article  PubMed  Google Scholar 

  22. Patwardhan AG, Khayatzadeh S, Nguyen NL et al (2016) Is cervical sagittal imbalance a risk factor for adjacent segment pathomechanics after multilevel fusion? Spine 41(10):E580–E588

    Article  PubMed  Google Scholar 

  23. Havey RM, Goodsitt J, Khayatzadeh S et al (2015) Three-dimensional computed tomography-based specimen-specific kinematic model for ex vivo assessment of lumbar neuroforaminal space. Spine 40(14):E814–E822

    Article  PubMed  Google Scholar 

  24. Yoganandan N, Pintar FA, Zhang J, Baisden JL (2009) Physical properties of the human head: mass, center of gravity and moment of inertia. J Biomech 42:1177–1192

    Article  PubMed  Google Scholar 

  25. Madsen DP, Sampson WJ, Townsend GC (2008) Craniofacial reference plane variation and natural head position. Eur J Orthod 30:532–540

    Article  PubMed  Google Scholar 

  26. Kapandji IA (2007) The physiology of the joints, vol 3. Churchill Livingstone, Edinburgh, New York

    Google Scholar 

  27. McKenzie R (1983) Treat your own neck. Spinal Publications, Waikanae

    Google Scholar 

  28. Neumann D (2010) Kinesiology of the musculoskeletal system: foundations for rehabilitation. Mosby/Elsevier, St. Louis

    Google Scholar 

  29. Cleland JA, Glynn P, Whitman JM et al (2007) Short-term effects of thrust versus nonthrust mobilization/manipulation directed at the thoracic spine in patients with neck pain: a randomized clinical trial. Phys Ther 87(4):431–440

    Article  PubMed  Google Scholar 

  30. Humphreys SC, Hodges SD, Patwardhan A et al (1998) The natural history of the cervical foramen in symptomatic and asymptomatic individuals aged 20–60 years as measured by magnetic resonance imaging. A descriptive approach. Spine 23:2180–2184

    CAS  Article  PubMed  Google Scholar 

  31. Ebraheim NA, Liu J, Shafiq Q et al (2006) Quantitative analysis of changes in cervical intervertebral foramen size with vertebral translation. Spine 31:E62–E65

    Article  PubMed  Google Scholar 

  32. Kitagawa T, Fujiwara A, Kobayashi N et al (2004) Morphologic changes in the cervical neural foramen due to flexion and extension: in vivo imaging study. Spine 29:2821–2825

    Article  PubMed  Google Scholar 

  33. Humphreys SC, Chase J, Patwardhan A et al (1998) Flexion and traction effect on C5–C6 foraminal space. Arch Phys Med Rehabil 79:1105–1109

    CAS  Article  PubMed  Google Scholar 

  34. Yoo JU, Zou D, Edwards WT, Bayley J, Yuan HA (1992) Effect of cervical spine motion on the neuroforaminal dimensions of human cervical spine. Spine 17:1131–1136

    CAS  Article  PubMed  Google Scholar 

  35. Muhle C, Resnick D, Ahn JM, Sudmeyer M, Heller M (2001) In vivo changes in the neuroforaminal size at flexion-extension and axial rotation of the cervical spine in healthy persons examined using kinematic magnetic resonance imaging. Spine 26:E287–E293

    CAS  Article  PubMed  Google Scholar 

  36. Jenis LG, Banco S, Jacquemin JJ, Lin KH (2004) The effect of posterior cervical distraction on foraminal dimensions utilizing a screw-rod system. Spine 29:763–766

    Article  PubMed  Google Scholar 

  37. Pingel A, Kandziora F (2013) Anterior decompression and fusion for cervical neuroforaminal stenosis. Eur Spine J 22:671–672

    Article  PubMed  PubMed Central  Google Scholar 

  38. Hojo Y, Ito M, Abumi K et al (2011) A late neurological complication following posterior correction surgery of severe cervical kyphosis. Eur Spine J 20:890–898

    Article  PubMed  Google Scholar 

  39. Radhakrishnan K, Litchy WJ, O’Fallon WM, Kurland LT (1994) Epidemiology of cervical radiculopathy. A population-based study from Rochester, Minnesota, 1976 through 1990. Brain 117(Pt 2):325–335

    Article  PubMed  Google Scholar 

  40. Kalmanson O, Khayatzadeh S, Germanwala A et al (2016) The effects of forward head posture on the suboccipital triangle region. In: 16th Annual Meeting of International Society for the Advancement of Spine Surgery. Las Vegas

  41. Fakhran S, Qu C, Alhilali LM (2016) Aug) Effect of the Suboccipital Musculature on Symptom Severity and Recovery after Mild Traumatic Brain Injury. AJNR Am J Neuroradiol 37:1556–1560

    CAS  Article  PubMed  Google Scholar 

  42. Alix ME, Bates DK (1999) Oct) A proposed etiology of cervicogenic headache: the neurophysiologic basis and anatomic relationship between the dura mater and the rectus posterior capitis minor muscle. J Manip Physiol Ther 22:534–539

    CAS  Article  Google Scholar 

  43. Lee MY, Lee HY, Yong MS (2014) Nov) characteristics of cervical position sense in subjects with forward head posture. J Phys Ther Sci 26:1741–1743

    Article  PubMed  PubMed Central  Google Scholar 

  44. Nemmers TM, Miller JW (2008) Factors influencing balance in healthy community-dwelling women age 60 and older. J Geriatr Phys Ther 31:93–100

    Article  PubMed  Google Scholar 

  45. Naja ZM, El-Rajab M, Al-Tannir MA, Ziade FM, Tawfik OM (2006) Occipital nerve blockade for cervicogenic headache: a double-blind randomized controlled clinical trial. Pain Pract 6(2):89–95

    Article  PubMed  Google Scholar 

  46. Inan N, Ceyhan A, Inan L, Kavaklioglu O, Alptekin A, Unal N (2001) C2/C3 nerve blocks and greater occipital nerve block in cervicogenic headache treatment. Funct Neurol 16(3):239–243

    CAS  PubMed  Google Scholar 

  47. Gabrhelik T, Michalek P, Adamus M (2011) Pulsed radiofrequency therapy versus greater occipital nerve block in the management of refractory cervicogenic headache—a pilot study. Prague Med Rep 112(4):279–287

    CAS  PubMed  Google Scholar 

  48. Lauretti GR, Correa SW, Mattos AL (2015) Efficacy of the greater occipital nerve block for cervicogenic headache: comparing classical and subcompartmental techniques. Pain Pract 15(7):654–661

    Article  PubMed  Google Scholar 

  49. Hilibrand AS, Robbins M (2004) Adjacent segment degeneration and adjacent segment disease: the consequences of spinal fusion? Spine J 4:190S–194S

    Article  PubMed  Google Scholar 

  50. Ishihara H, Kanamori M, Kawaguchi Y, Nakamura H, Kimura T (2004) Adjacent segment disease after anterior cervical interbody fusion. Spine J 4:624–628

    Article  PubMed  Google Scholar 

  51. Riew KD, Schenk-Kisser JM, Skelly AC (2012) Adjacent segment disease and C-ADR: promises fulfilled? Evid Based Spine Care J 3:39–46

    Article  PubMed  PubMed Central  Google Scholar 

  52. Carrier CS, Bono CM, Lebl DR (2013) Evidence-based analysis of adjacent segment degeneration and disease after ACDF: a systematic review. Spine J 13:1370–1378

    Article  PubMed  Google Scholar 

  53. Lawrence BD, Hilibrand AS, Brodt ED, Dettori JR, Brodke DS (2012) Predicting the risk of adjacent segment pathology in the cervical spine: a systematic review. Spine 37:52–64

    Article  Google Scholar 

  54. Hansen MA, Kim HJ, Van Alstyne EM, Skelly AC, Fehlings MG (2012) Does postsurgical cervical deformity affect the risk of cervical adjacent segment pathology? A systematic review. Spine 37:75–84

    Article  Google Scholar 

  55. Faldini C, Pagkrati S, Leonetti D, Miscione MT, Giannini S (2011) Sagittal segmental alignment as predictor of adjacent-level degeneration after a cloward procedure. Clin Orthop Relat Res 469:674–681

    Article  PubMed  Google Scholar 

  56. Katsuura A, Hukuda S, Saruhashi Y, Mori K (2001) Kyphotic malalignment after anterior cervical fusion is one of the factors promoting the degenerative process in adjacent intervertebral levels. Eur Spine J 10:320–324

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  57. Kulkarni V, Rajshekhar V, Raghuram L (2004) Accelerated spondylotic changes adjacent to the fused segment following central cervical corpectomy: magnetic resonance imaging study evidence. J Neurosurg 100:2–6

    Article  PubMed  Google Scholar 

  58. Park MS, Kelly MP, Lee DH et al (2014) Sagittal alignment as a predictor of clinical adjacent segment pathology requiring surgery after anterior cervical arthrodesis. Spine J 14:1228–1234

    Article  PubMed  Google Scholar 

  59. Fuller DA, Kirkpatrick JS, Emery SE, Wilber RG, Davy DT (1998) A kinematic study of the cervical spine before and after segmental arthrodesis. Spine 23:1649–1656

    CAS  Article  PubMed  Google Scholar 

  60. Maiman DJ, Kumaresan S, Yoganandan N, Pintar FA (1999) Biomechanical effect of anterior cervical spine fusion on adjacent segments. Biomed Mater Eng 9:27–38

    CAS  PubMed  Google Scholar 

  61. Schulte K, Clark CR, Goel VK (1989) Kinematics of the cervical spine following discectomy and stabilization. Spine 14:1116–1121

    CAS  Article  PubMed  Google Scholar 

  62. Eck JC, Humphreys SC, Lim TH et al (2002) Biomechanical study on the effect of cervical spine fusion on adjacent-level intradiscal pressure and segmental motion. Spine 27:2431–2434

    Article  PubMed  Google Scholar 

  63. Dmitriev AE, Cunningham BW, Hu N et al (2005) Adjacent level intradiscal pressure and segmental kinematics following a cervical total disc arthroplasty: an in vitro human cadaveric model. Spine 30:1165–1172

    Article  PubMed  Google Scholar 

  64. Cunningham BW, Hu N, Zorn CM, McAfee PC (2010) Biomechanical comparison of single- and two-level cervical arthroplasty versus arthrodesis: effect on adjacent-level spinal kinematics. Spine J 10:341–349

    Article  PubMed  Google Scholar 

  65. Dmitriev AE, Kuklo TR, Lehman RA, Rosner MK (2007) Stabilizing potential of anterior, posterior, and circumferential fixation for multilevel cervical arthrodesis: an in vitro human cadaveric study of the operative and adjacent segment kinematics. Spine 32:E188–E196

    Article  PubMed  Google Scholar 

  66. Park DH, Ramakrishnan P, Cho TH et al (2007) Effect of lower two-level anterior cervical fusion on the superior adjacent level. J Neurosurg Spine 7:336–340

    Article  PubMed  Google Scholar 

  67. Leahy PD, Puttlitz CM (2016) Addition of lateral bending range of motion measurement to standard sagittal measurement to improve diagnosis sensitivity of ligamentous injury in the human lower cervical spine. Eur Spine J 25(1):122–126

    Article  PubMed  Google Scholar 

  68. Bartolomei JC, Theodore N, Sonntag VK (2005) Adjacent level degeneration after anterior cervical fusion: a clinical review. Neurosurg Clin N Am 16:575–587

    Article  PubMed  Google Scholar 

  69. Tan JS, Uppuganti S (2012) Cumulative multiple freeze-thaw cycles and testing does not affect subsequent within-day variation in intervertebral flexibility of human cadaveric lumbosacral spine. Spine 37(20):E1238–E1242

    Article  PubMed  Google Scholar 

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Acknowledgements

Research funding was received from the Department of Veterans Affairs, Washington, DC (Grant #1I01RX001269-01A2).

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Authors and Affiliations

  1. Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines, IL, USA

    Avinash G. Patwardhan, Saeed Khayatzadeh, Robert M. Havey, Leonard I. Voronov & Alexander J. Ghanayem

  2. Loyola University Stritch School of Medicine, Maywood, IL, USA

    Avinash G. Patwardhan, Robert M. Havey, Leonard I. Voronov, Olivia Kalmanson & Alexander J. Ghanayem

  3. Northwestern Feinberg School of Medicine, Chicago, IL, USA

    Zachary A. Smith

  4. Wentworth Spine Clinic, Sydney, NSW, Australia

    William Sears

  5. Department of Orthopaedic Surgery and Rehabilitation, Loyola University Medical Center, 2160 S. First Avenue, Maywood, IL, 60153, USA

    Avinash G. Patwardhan

Authors
  1. Avinash G. Patwardhan
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  2. Saeed Khayatzadeh
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  3. Robert M. Havey
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  4. Leonard I. Voronov
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Correspondence to Avinash G. Patwardhan.

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Patwardhan, A.G., Khayatzadeh, S., Havey, R.M. et al. Cervical sagittal balance: a biomechanical perspective can help clinical practice. Eur Spine J 27, 25–38 (2018). https://doi.org/10.1007/s00586-017-5367-1

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Keywords

  • Cervical sagittal alignment
  • Sagittal balance
  • C2–C7 SVA
  • T1 slope
  • Forward head posture
  • Biomechanics