Eur J Orthop Surg Traumatol (2013) 23 (Suppl 1):S47–S51 DOI 10.1007/s00590-012-0966-3
Sagittal alignment of the cervical spine after neck injury Michail Beltsios • Olga Savvidou • Evanthia A. Mitsiokapa Andreas F. Mavrogenis • Angelos Kaspiris • Nikolaos Efstathopoulos • Panayiotis J. Papagelopoulos
Received: 27 December 2011 / Accepted: 18 February 2012 / Published online: 10 March 2012 Ó Springer-Verlag 2012
Abstract The normal sagittal alignment of the cervical spine is lordotic and is affected by the posture of the head and neck. The question of whether loss of cervical lordosis is the result of muscle spasm after injury or a normal variation, and the clinical significance of such changes in sagittal profile of the cervical spine has been an issue of several studies. The purpose of this paper is to study the incidence of normal cervical lordosis and its changes after neck injury compared to the healthy population. We studied the lateral radiographs of the cervical spine of 60 patients with neck injury compared to 100 patients without a neck injury. Lateral radiographs were obtained in the standing or sitting position, and the curvature of the cervical spine was measured using the angle formed between the inferior end plates of the C2 and C7 vertebrae. In the patients without neck injury, lordotic and straight cervical spine sagittal alignment was observed in 36.5% each, double curvature in 17%, and kyphotic in 10%. In the patients with neck injury, lordotic sagittal alignment was observed in 36%, straight in 34%, double curvature in 26% M. Beltsios (&) O. Savvidou A. Kaspiris Department of Orthopaedics, Thriasio Hospital, 19600 Elefsis, Greece e-mail: [email protected]
E. A. Mitsiokapa Department of Physical Medicine and Rehabilitation, General University Hospital of Patras, Rio, Greece A. F. Mavrogenis P. J. Papagelopoulos First Department of Orthopaedics, Athens University Medical School, 41 Ventouri Street, 15562 Holargos, Athens, Greece e-mail: [email protected]
; [email protected]
N. Efstathopoulos Second Department of Orthopaedics, Athens University Medical School, Athens, Greece
and kyphotic in 4%. No significant difference between the two groups regarding all types of sagittal alignment of the cervical spine was found (p [ 0.100). The alterations in normal cervical lordosis in patients with neck injury must be considered coincidental. These alterations should not be associated with muscle spasm caused by neck pain. Keywords
Cervical spine Lordosis Neck injury
Introduction Hippocrates  and Galinos  were the first who introduced the terms lordosis and kyphosis for the spine [3, 4]. The thoracic and sacrococcygeal are the primary or adjustment spinal curvatures that are developed during endometrial life, while the cervical and lumbar curvatures are secondary or compensatory and maintain balance in the upright position [5–10]. Some reported that it is the thoracic kyphosis that determines cervical lordosis , while others support that the movements of the baby as a result of the gasp reflect and the effect of muscles on the osseous spine result in the secondary cervical curve . The typical sagittal alignment of the cervical spine is lordotic , with normal values ranging from 20 to 35° [3, 4, 6–10]. Cervical lordosis becomes apparent at 3–4 months of life when the baby lifts its head and becomes more pronounced at 9 months when the baby obtains the sitting position [12, 13]. Thereafter, lordosis is the more common sagittal profile of the cervical spine [6, 8, 14, 15]. Following cervical spine injury, it has been a general belief that the loss of lordosis is due to muscle spasm or ligamentous injury [9, 16]. However, previous studies considered the loss of lordosis and sagittal alterations of the cervical spine such as straight, kyphotic or double
curvature as normal variations [3, 6, 14]. We carried out this observational study to evaluate the sagittal alignment of the cervical spine and to confirm previous reports regarding the normal variations of cervical spine sagittal alignment and its association with neck injury.
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Radiographs of the cervical spine were repeated only if there were clinical symptoms. The mean follow-up of these patients was 8 weeks (range, 2 weeks–4 months).
Results Patients and methods We retrospectively studied the medical files of 160 patients examined at the authors’ institutions from January 2007 to April 2007. Sixty patients (54 men and 6 women; mean age, 27 years; range, 20–35 years) presented to the emergency department with acute neck pain after cervical spine injury without neurological deficits and radiographic findings of bone or ligamentous injury. One hundred patients (84 men and 16 women; mean age 27 years; range, 25–35 years) did not have cervical spine injury or any clinical symptoms from the cervical spine; these patients had cervical spine radiographs for the differential diagnosis work-up for headache, shoulder pain, upper extremity pain, dysphagia and thoracic outlet syndrome. All patients gave written informed consent for their data to be included in this study. This study was approved by the Institutional Review Board/Ethics Committee of the authors’ institutions. In all patients, the lateral radiograph of the cervical spine was obtained in the standing or sitting position with the arms hanging free at the lateral thorax, and the cervical spine in neutral position in the sense of the patients’ comfort, which in the patients with neck injury was causing the least pain. The curvature of the cervical spine (C2–C7) was measured in the lateral radiographs using the angle formed between the inferior end plates of the C2 and C7 vertebrae . All patients with cervical spine injury were treated with a 5-day period of cervical soft collar immobilization, a 10-day period of non-steroidal anti-inflammatory drugs administration, and routine follow-up evaluation.
Fig. 1 Four types of sagittal alignment of the CS of the 60 patients with neck injury: lordotic (a), straight (b), double curvature (c) and kyphotic (d). The patient with double curvature, C3–C4 and C4–C5
Twenty-two (36.5%) of the 60 patients with cervical spine injury had lordotic cervical spine sagittal alignment, 22 patients (36.5%) had straight, ten patients (17%) had double curvature, and six patients (10%) had kyphotic sagittal alignment (Fig. 1). Eighteen of the 60 patients with neck injury had repeat radiographs of the cervical spine within 2–3 weeks after the injury because of persistent symptoms. In two of the 18 patients, repeat radiographs showed change in the sagittal alignment of the cervical spine from straight (at the time of injury) to lordotic (at repeat imaging examination). In the remaining 16 of the 18 patients, repeat radiographs did not show any change in sagittal alignment of the cervical spine from the radiographs obtained at the time of injury. Thirty-six (36%) of the 100 patients without cervical spine injury had lordotic sagittal alignment, 34 patients (34%) had straight CS, 26 patients (26%) had double curvature, and four patients (4%) had kyphosis (Fig. 2). Overall, lordotic sagittal alignment of the CS was the most common (58 of the 160 patients); however, a statistically significant difference of the sagittal alignments of the cervical spine between the patients with and without cervical spine injury was not observed (p [ 0.100) (Table 1). Variable radiographic findings were observed in the radiographs of patients of both groups, such as anterolisthesis and degenerative disk disease (Fig. 1c); possibly, these findings may have contributed to neck pain in these patients. However, at the last clinical examination, all patients were asymptomatic and completely returned to their previous activities.
anterolisthesis, and C5–C6 discopathy was asymptomatic at the last clinical examination
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Fig. 2 Four types of sagittal alignment of the CS of the 100 patients without neck injury: lordotic (a), straight (b), double curvature (c) and kyphotic (d)
Table 1 Sagittal alignment of the CS of the patients included in this series Patients
A statistically significant difference between the two groups was not observed (p = 0.100)
Discussion Lordosis is the more common sagittal alignment of the cervical spine [6, 8, 14, 15]. Less common, although normal variants are straight, kyphotic and angulated curvatures [6, 8, 14]. We carried out this study to evaluate the types of sagittal alignment of the cervical spine in patients with and without neck injury and to confirm previous reports [6, 8, 14, 15], regarding the association the cervical spine curvature with neck injury. On the basis of our results, in patients with and without cervical spine injury, although lordotic sagittal alignment was the most common [6, 8, 14, 15], straight, angulated and kyphotic curvatures were also observed. Since no statistical significance regarding the sagittal alignment was found between patients with and without cervical spine injury, and all patients were examined with the same radiographic technique in the sitting or standing posture, these curvatures should be considered normal variants and not pathological sagittal alignments of the cervical spine. We acknowledge three limitations in this study. First, the number of patients is small, the two groups were not equal, most subjects were men, and their body type was not controlled; in this setting, our results may be regarded with caution. Second, the sample is not adequate for comparison, as the pathology of the patients without neck injury may have produced an irritation to the area, causing
muscular spasm and change of cervical alignment. Since the patients without a cervical spine injury were not volunteers but patients having radiographs of the cervical spine for possible disorders of the head, neck or shoulder, they likely represent a specific selection rather than a random sample of the normal population. A group of asymptomatic volunteers would have been ideal; however, for radiation protection reasons this would have been unethical. For the same reason, radiographic examination of the sagittal alignment of the whole spine was not carried out, and hence, any influence of the sagittal alignment of the lower spinal regions as a possible determinant of cervical spine curvature  remains uncertain. Third, preinjury cervical spine radiographs of the patients with neck injury are not available; if such radiographs were available, this would have strengthened this study. In addition, other imaging studies such as computed tomography and magnetic resonance imaging were not carried out since neurological symptoms were not observed, and neck pain resolved completely after a short period of cervical spine collar immobilization and non-steroidal anti-inflammatory drugs administration. The methods for the radiographic measurement of the spinal curvature vary [3–10, 14, 15]. In addition, there is only vague information regarding the exact degrees of cervical spine sagittal alignment, and these appear to be highly dependent on the method of assessment [3–10]. A visual subjective classification into kyphotic, straight or lordotic sagittal alignment has proven to be unreliable . Alternatively, as in the present study, objective methods of assessment of cervical spine sagittal alignment allow for more accurate measurement with minimal intra- and interobserver variability [7, 14, 16–19]. Moreover, it is known that factors such as pelvic tilt, sitting or standing position, shape of the backrest when sitting, and head position can influence the sagittal curve of the cervical
spine [4, 7, 14, 20–24]. These factors should be considered when obtaining radiographs of the cervical spine. For the purpose of comparative studies and reproducibility of the results, the radiographs should be always taken with the head and neck in the same posture; it is recommended that posture should be neutral that is where there is minimal muscle activity [4, 14, 18]. Neutral position can be obtained by asking the patients to flex and extend their neck with the eyes closed until they find a comfortable position of equilibrium that is the neutral position . However, since the position of the neck’s equilibrium varies from individual to individual, a different cervical spine curvature angle may occur. The posture of the head also affects the curvature of the cervical spine [7, 20, 21]. In a study, 70 cervical spine were lordotic in the neutral relaxed position of the neck; however, when the neck was placed in the military position (chin lowered), lordotic cervical spine reduced to 23, nine became straight, 15 became kyphotic, and nine developed double curvatures . Similarly, others reported that when lowering the chin of the patients, 50–70% of the cervical spine loses lordosis and becomes straight or kyphotic [20, 21]. Other factors that may influence the cervical spine curvature are the thoracic kyphosis, the congenital or developmental vertical hyperplasia of the facets, the degenerative cervical spine disk disease, the length of the cervical spine, the angle of the facets, the height index of the vertebrae, the cervical spine muscles and ligaments in the extreme positions of the cervical spine, and the center of weight of the head . Muscle spasm and loss of normal cervical spine lordosis are the common findings after neck injury [4, 8, 19, 25–30]; however, there is often concern in clinical practice whether it indicates osseoligamentous injury and unstable injuries such as intervertebral disk rupture , posterior spinal joints injury , ligament stretch or traumatic spondylosis [8, 19], or it is a normal variant [4, 25–27]. Previous studies attributed non-lordotic cervical spine after injury to muscle spasm [25, 28]. Others stated that posterior muscles are bulkier than anterior and muscle spasm should cause hyperlordosis due to extension of the head and neck rather than cervical spine straightening or kyphosis . In patients with whiplash injuries of the cervical spine, loss of lordosis was more frequent compared to other types of cervical spine injuries; in these cases, loss of lordosis occurs because of hyperextension of the lower and flexion of the upper cervical spine [31–33]. Moreover, a relationship between cervical spine sagittal alignment and outcome after neck injury has not been reported [8, 14, 19, 34–37]; decreased or reversed lordosis after cervical spine injury has not been related to longer period of pain, incapacity for work or development of degenerative spondylosis [34–37]. In the present study, a statistically significant difference of cervical spine sagittal alignments changes in patients with
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and without cervical spine injury was not observed; all types of sagittal alignment were observed in both groups of patients, and variable radiographic findings were observed. However, at the last examination, all cervical spine injured patients were asymptomatic and completely returned to their previous daily living and occupational activities. Thus, cervical spine sagittal alignment changes after neck injury should be considered coincidental and not indicative of muscle spasm or osseoligamentous injury. Conflict of interest
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