J Korean Soc Spine Surg.  2016 Mar;23(1):54-62. 10.4184/jkss.2016.23.1.54.

Kyphotic Neck and Correlation With Clinical Outcomes

• Min WK
• Mun JU

• KMID: 2161013
• DOI: http://doi.org/10.4184/jkss.2016.23.1.54

Abstract

STUDY DESIGN: A literature review regarding the correlation between a kyphotic neck and its clinical outcomes.
OBJECTIVES
This review examines normal cervical alignment, methods for assessing alignment, a specific correlation between kyphotic neck and clinical outcomes, and indications and methods of surgical treatment. SUMMARY OF LITERATURE REVIEW: Cervical kyphotic deformity is problematic in terms of HRQOL due to nerve damage or loss of horizontal gaze.
MATERIALS AND METHODS
Review of the literature.
RESULTS
Cervical kyphosis can be caused by postlaminectomy, degenerative disc disease, and trauma, and the symptoms exhibit diverse clinical progression including compensatory mechanisms, adjacent segment disease, changes in quality of life, and cervical myelopathy. Given the serious complications of cervical surgery, we need a deep understanding of spine anatomy, preoperative planning, and correction methods.
CONCLUSIONS
It is vital to investigate cervical sagittal alignment and to perform intensive treatment and corrective surgery to achieve better clinical outcomes.

Keyword

Cervical spine alignment; Cervical kyphosis; Cervical adjacent-segment disease; Cervical myelopathy; Sagittal vertical axis

MeSH Terms

Congenital Abnormalities
Kyphosis
Neck*
Quality of Life
Spinal Cord Diseases
Spine

Figure

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  Fig. 1. Sagittal radiographs showing 3 different methods used to determine cervical lordosis. (A) The 4-line method for measuring cervical Cobb angles. This method includes drawing a line either parallel to the inferior endplate of C-2 or extending from the anterior tubercle of C-1 to the posterior margin of the spinous process, and another line parallel to the inferior endplate of C-7. Perpendicular lines are then drawn from each of the 2 lines noted above, and the angle subtended between the crossing of the perpendicular lines is the cervical curvature angle. (B) The Jackson physiological stress lines method for measuring cervical curvature. The method requires drawing 2 lines, both parallel to the posterior surface of the C-7 and C-2 vertebral bodies and measuring the angle between them. (C) The Harrison method for measuring cervical curvature. The Harrison posterior tangent method involves drawing lines that are parallel to the posterior surfaces of all cervical vertebral bodies from C-2 to C-7 and then summing the segmental angles for an overall cervical curvature angle. Adapted from Sheer J.K et al; J Neurosurg Spine. 2013;19(2):141-7)

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  Fig. 2. Visual representation of the technique used to measure cervical SVA. The arrows represent the distance between the posterior superior corner of C7 and a plumb line dropped from C2 (C2-C7 SVA), the external auditory meatus (EAM; CGH-C7 SVA), and C1 (C1-C7 SVA). SVA, sagittal vertical axis; CGH, center of gravity of head. Adapted from Tang JA et al; Neurosurgery. 2012;71(3):662-9.3)

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  Fig. 3. Artist's illustration of the following spinal measurements Chin-brow vertical angle(CBVA) T1 slope. Adapted from Ames CP et al; Spine (Phila Pa 1976). 2013;38(22 Suppl 1):S149-60.1)

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  Fig. 4. Upper: Chain of correlation between pelvic incidence and regional sagittal parameters with the corresponding Pearson coefficient (r) values. A large pelvic incidence requires a large lumbar lordosis (r=0.52). An increase of lumbar lordosis is correlated with an increased thoracic kyphosis (r=-0.34), which is correlated with an increased cervical lordosis (r= -0.51). Lower:Correlation between pelvic tilt and lumbar/ cervical lordosis. A loss of lumbar lordosis is correlated with a pelvic retroversion acting as compensatory mechanisms (r=-0.29). Pelvic retro-version is also correlated with an increased cervical lordosis (r=0.31). Adapted from Blondel et al., unpublished data, 2012.

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  Fig. 5. Comparison of effects of positive sagittal alignment on NDI and PCS scores. Left, patient with C2-C7 SVA of 20.9mm exhibiting PCS score of 55.1 and NDI score of 3 (no disability). Right, patient with C2-C7 SVA of 59.2 mm exhibiting PCS score of 28 and NDI score of 37 (severe disability). SVA, sagittal vertical axis; NDI, neck disability index; PCS, physical component score Adapted from Tang JA et a l; Neurosurgery. 2012;71(3):662-9.3)

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