View/Download PDF
Review Article
2019
:10;
147
doi:
10.25259/SNI_339_2019
CROSSMARK LOGO Buy Reprints
PDF

Which factors predict the loss of cervical lordosis following cervical laminoplasty? A review of various indices and their clinical implications

Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
Corresponding author: Sachin A. Borkar, Department of Neurosurgery, 720, CNC, All India Institute of Medical Sciences, New Delhi - 110 029, India. sachin.aiims@gmail.com
Licence
This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Sharma R, Borkar SA, Goda R, Kale SS. Which factors predict the loss of cervical lordosis following cervical laminoplasty? A review of various indices and their clinical implications. Surg Neurol Int 2019;10:147.

Abstract

Background:

Many patients undergoing laminoplasty develop postoperative loss of cervical lordosis or kyphotic alignment of cervical spine despite sufficient preoperative lordosis. This results in poor surgical outcomes.

Methods:

Here, we reviewed the relationship between multiple radiological parameters of cervical alignment that correlated with postoperative loss of cervical lordosis in patients undergoing laminoplasty.

Results:

Patient with a high T1 slope (T1S) has more lordotic alignment of the cervical spine preoperatively and is at increased risk for the loss of cervical lordosis postlaminoplasty. Those with lower values of difference between T1S and Cobb’s angle (T1S-CL) and CL-T1S ratio have higher risks of developing a loss of the cervical lordosis postoperatively. Alternatively, C2-C7 lordosis, neck tilt, cervical range of motion, and thoracic kyphosis had no role in predicting the postlaminoplasty kyphosis.

Conclusion:

Among various radiological parameters, the preoperative T1S is the most important factor in predicting the postoperative loss of the cervical lordosis/alignment following laminoplasty.

Keywords

Cervical laminoplasty
Loss of cervical lordosis
T1 slope
C2-C7 lordosis
C2-C7 Cobb’s angle
C2-C7 sagittal vertical axis
C2-C3 disc angle

INTRODUCTION

Although laminectomy has better long-term clinical and radiological outcomes, laminoplasty is still favored for the management of cervical spondylotic myelopathy as it preserves the cervical range of motion (ROM) with a lower risk of postoperative kyphosis.[3,14-17]. Despite an adequate preoperative cervical lordosis, increases in the T1 slope (T1S) may result in postlaminoplasty kyphosis.[1,2,4-6] Here, we highlight the relationship between T1S and other radiological indicators of cervical alignment and correlate these with postlaminoplasty kyphosis/loss of lordosis.

METHODS

Measures of cervical alignment

Multiple studies have described various indices that help predict the risk of loss of cervical lordosis in postlaminoplasty patients [Table 1, Figure 1].[9,11-13]

Table 1:: Description of indices affecting cervical alignment.
Figure 1:: The lateral X-ray of cervical spine showing various radiological measurements.

RESULTS

T1S

The T1S is one of the most important indices that can help predict the postlaminoplasty loss of cervical lordosis. Notably, the preoperative cervical lordosis (C2-C7 Cobb’s angle) was greater in patients with higher T1S versus those with lower T1S; these patients have a higher risk of kyphosis postlaminoplasty.[2,5-7,18] Lee et al.[10] concluded that patients with a T1S of >29° are more likely to exhibit postlaminoplasty kyphosis/loss of lordosis of more than 5° versus those with T1S of <29°.

C2-C7 sagittal vertical axis (SVA)

Several studies have shown that the preoperative C2-C7 SVA had no significant correlation with the postlaminoplasty loss of cervical lordosis.[2,5,6,18] Alternatively, Zhang et al.[18] concluded that C2-C7 SVA was positively correlated with loss of cervical lordosis following laminoplasty.[2,5,6,18] Lin et al.[13] showed the combined effect of T1S and C2-C7 SVA on predicting loss of cervical lordosis. Patient with low T1S (≤20°) and large C2-C7 SVA (>22 mm) surprisingly had an increased cervical lordosis postlaminoplasty.

Other factors are predictive of postlaminoplasty kyphosis

There are multiple other factors that predict postlaminoplasty kyphosis. Li et al.[11] concluded that patients with high Cobb’s angle-T1S ratio (CL/T1S) have a higher risk of kyphosis versus those with low CL/T1S. Kim et al.[5] and Zhang et al.[18] showed no relationship between cervical ROM and the risk for postoperative kyphosis. Similar to cervical ROM, neck tilt (NT) a measure of cervical spine tilt with respect to sternum, also does not predict the loss of cervical lordosis following laminoplasty.[6] Thoracic kyphosis (TK) is, however, directly related to cervical lordosis.[8] Cephalad vertebral level undergoing laminoplasty has also emerged as a new risk factor for loss of cervical lordosis following laminoplasty.

CONCLUSION

A high T1S and C2-C7 SVA are the most predictive factors for postlaminoplasty kyphosis. Those risk factors that do not contribute to this include; (1) the preoperative C2-C7 lordosis, NT, cervical ROM, and TK.

Financial support and sponsorship

None.

Conflicts of interest

There are no conflicts of interest.

REFERENCES

  1. , , , , , , . Lordotic alignment and posterior migration of the spinal cord following en bloc open-door laminoplasty for cervical myelopathy: A magnetic resonance imaging study. J Neurol. 1996;243:626-32
    [Google Scholar]
  2. , , , , , , . Does preoperative T1 slope affect radiological and functional outcomes after cervical laminoplasty? Spine (Phila Pa 1976). 2014;39:E1575-81
    [Google Scholar]
  3. , , , , , , . Minimum 10-year followup after en bloc cervical laminoplasty. Clin Orthop Relat Res. 2003;411:129-39
    [Google Scholar]
  4. , , , , , , . Myoarchitectonic spinolaminoplasty: Efficacy in reconstituting the cervical musculature and preserving biomechanical function. J Neurosurg Spine. 2007;7:293-304
    [Google Scholar]
  5. , , , , . T1 slope as a predictor of kyphotic alignment change after laminoplasty in patients with cervical myelopathy. Spine (Phila Pa 1976). 2013;38:E992-7
    [Google Scholar]
  6. , , , , , , . Relationship between T1 slope and loss of lordosis after laminoplasty in patients with cervical ossification of the posterior longitudinal ligament. Spine J. 2016;16:219-25
    [Google Scholar]
  7. , , , , , , . Adjacent-level range of motion and intradiscal pressure after posterior cervical decompression and fixation: An in vitro human cadaveric model. Spine (Phila Pa 1976). 2012;37:E778-85
    [Google Scholar]
  8. , , , , . Factors determining cervical spine sagittal balance in asymptomatic adults: Correlation with spinopelvic balance and thoracic inlet alignment. Spine J. 2015;15:705-12
    [Google Scholar]
  9. , , , , , , . A lower T1 slope as a predictor of subsidence in anterior cervical discectomy and fusion with stand-alone cages. J Korean Neurosurg Soc. 2017;60:567-76
    [Google Scholar]
  10. , , , , , , . The effect of C2-3 disc angle on postoperative adverse events in cervical spondylotic myelopathy. J Neurosurg Spine. 2018;30:38-45
    [Google Scholar]
  11. , , , , , , . Influence of the ratio of C2-C7 cobb angle to T1 slope on cervical alignment after laminoplasty. World Neurosurg. 2019;124:e659-66
    [Google Scholar]
  12. , , , , , , . The severity of operative invasion to the posterior muscular-ligament complex influences cervical sagittal balance after open-door laminoplasty. Eur Spine J. 2015;24:127-35
    [Google Scholar]
  13. , , , , , , . Impact of global spine balance and cervical regional alignment on determination of postoperative cervical alignment after laminoplasty. Medicine (Baltimore). 2018;97:e13111
    [Google Scholar]
  14. , , . Analysis of the cervical spine alignment following laminoplasty and laminectomy. Spinal Cord. 1999;37:20-4
    [Google Scholar]
  15. , . Cervical laminoplasty: A critical review. J Neurosurg. 2003;98:230-8
    [Google Scholar]
  16. , , , , , , . Long-term results of double-door laminoplasty for cervical stenotic myelopathy. Spine (Phila Pa 1976). 2001;26:479-87
    [Google Scholar]
  17. , , , , . Long-term follow-up of clinical and radiological outcome after cervical laminectomy. Eur Spine J. 2015;24:229-35
    [Google Scholar]
  18. , , , , , , . Predictors of cervical lordosis loss after laminoplasty in patients with cervical spondylotic myelopathy. Eur Spine J. 2017;26:1205-10
    [Google Scholar]
Show Sections