Cervical spine biomechanics: A review of the literature

Huelke, Donald F.; Nusholtz, Guy S.

doi:10.1002/jor.1100040212

Cited by 63 publications

(20 citation statements)

References 35 publications

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“…28 Regardless of the treatment modality, in-hospital mortality rates for patients with a Type II odontoid fracture remain significant at 10% 28 to 25%. 9,32 The significance of localized osteoporosis in the outcome of surgically stabilized Type II odontoid fractures has been demonstrated, 19,21 with less robust healing observed in a more osteoporotic cohort; osteoporotic bone was observed to promote the formation of a cone-shaped excavation around the screw shank, which may reduce anchorage of the screw at the densbody junction. 21 Although the current update to the guidelines issued by the Joint Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons makes no specific mention of osteoporosis, 28,29 the guidelines issued in 2002 7 referenced an article that identified severe osteoporosis as a contraindication to anterior screw fixation; CT attenuation allows rapid and quantitative characterization of the severity of bone loss.…”

Section: Discussionmentioning

confidence: 99%

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Osteoporosis in acute fractures of the cervical spine: the role of opportunistic CT screening

Emohare¹,

Dittmer

Morgan

et al. 2015

SPI

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OBJECT Recently published data make it possible to generate estimates of bone mineral density (BMD) by using CT attenuation; this innovation can save time and reduce costs. Although advanced age is associated with reduced BMD, especially in patients with a fracture of C-2, relatively few patients ever undergo formal dual x-ray absorptiometry studies. To the authors' knowledge, this is the first study to assess the utility of this technique in elucidating BMD in patients with an acute fracture of the cervical spine. METHODS Patients who presented to a Level I trauma center with an acute fracture of the cervical spine and underwent abdominal (or L-1) CT scanning either at admission or in the 6 months before or after the injury were evaluated. Using a picture-archiving and communication system, the authors generated regions of interest of similar size in the body of L-1 (excluding the cortex) and computed mean values for CT attenuation. The values derived were compared with threshold values, which differentiate between osteoporotic and nonosteoporotic states; age-stratified groups were also compared. RESULTS Of the 91 patients whose data were reviewed, 51 were < 65 years old (mean 43.2 years) and 40 were ≥ 65 years old (mean 80.9 years). The overall mean CT attenuation values (in Hounsfield units [HU]), stratified according to age, were 193.85 HU for the younger cohort and 117.39 HU for the older cohort; the result of a comparison between these two values was significant (p < 0.001). CONCLUSIONS Using opportunistic CT scanning, this study demonstrates the relative frequency of osteoporosis in acute fractures of the cervical spine. It also objectively correlates overall BMD with the known higher frequency of C-2 fractures in older patients. This technique harnesses the presence of opportunistic CT scans of the abdomen, which potentially reduces the need for the extra time and cost that may be associated with dual x-ray absorptiometry scanning.

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Section: Discussionmentioning

confidence: 99%

“…9 Much like bone in other parts of the spine, the cervical spine is affected by physiological processes such as aging and degeneration. In other parts of the spine, when fractures related to aging occur, the risk of future fractures increases.…”

mentioning

confidence: 99%

Osteoporosis in acute fractures of the cervical spine: the role of opportunistic CT screening

Emohare¹,

Dittmer

Morgan

et al. 2015

SPI

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“…We tested the FSU C5/6, as most cervical spine injuries occur at this level [8,10,23]. The types of artificial discoligamentous injuries we created were based on the findings of biomechanical studies dealing with injury patterns of the discoligamentous structures of the lower cervical spine, especially in whiplash injuries [8,23].…”

Section: Discussionmentioning

confidence: 99%

Load-displacement properties of the normal and injured lower cervical spine in vitro

Richter¹,

Wilke

Kluger³

et al. 2000

European Spine Journal

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IntroductionThe discoligamentous structures of the cervical spine are often involved in cervical spine injuries, for example in whiplash injuries. Although standard clinical imaging techniques, especially nuclear magnetic resonance imaging (MRI), allow the detection of discoligamentous injuries [9,13,24,30,31], few biomechanical data exist concerning the significance of the different discoligamentous structures for the load-displacement properties of the cervical spine under physiological loads. Several studies have been carried out to evaluate the load-displacement properties of the normal lower cervical spine in vitro [6,15,17,19,25] and in vivo [2,3,12,20], as well as in different types of artificial defect situations [6,18,26,32]. Variations in the study designs with regard to testing protocol and type of artificial defect make comparison between the different studies difficult. Few studies have tested artificial discoligamentous defects in the lower cervical spine under near-physiological loads [25,26,32].The objective of this study was therefore to evaluate the type and amount of instability caused by injury of different discoligamentous structures of the cervical spine in comparison to the intact cervical spine.Abstract The objective of this study was to determine which discoligamentous structures of the lower cervical spine provide significant stability with regard to different loading conditions. Accordingly, the loaddisplacement properties of the normal and injured lower cervical spine were tested in vitro. Four artificially created stages of increasing discoligamentous instability of the segment C5/6 were compared to the normal C5/6 segment. Six fresh human cadaver spine segments C4-C7 were tested in flexion/extension, axial rotation, and lateral bending using pure moments of ± 2.5 Nm without axial preload. Five conditions were investigated consecutively: (1) the intact functional spinal unit (FSU) C5/6; (2) the FSU C5/6 with the anterior longitudinal ligament and the intertransverse ligaments sectioned; (3) the FSU C5/6 with an additional 10-mm-deep incision of the anterior half of the anulus fibrosus and the disc; (4) the FSU C5/6 with additionally sectioned ligamenta flava as well as interspinous and supraspinous ligaments; (5) the FSU C5/6 with additional capsulotomy of the facet joints. In flexion/extension, significant differences were observed concerning range of motion (ROM) and neutral zone (NZ) for all four stages of instability compared to the intact FSU. In axial rotation, only the stage 4 instability showed a significantly increased ROM and NZ compared to the intact FSU. For lateral bending, no significant differences were observed. Based on these data, we conclude that flexion/extension is the most sensitive load-direction for the tested discoligamentous instabilities.

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“…However, they are all based on relative moment of the cervical vertebrae against each other, resulting from different motion vectors of the head and the thorax during, for example, a low-speed rear-end impact (Backaitis, 1993;Huelke, 1986;Walz, 1995;Yoganandan, 1998a). Relative motion between, for example, the first thoracic vertebra and the head as observed in tests with volunteers, PMTS (post-mortem test subjects), or (modern) dummies often barely exceeds motion corridors of voluntary movement of the head and neck.…”

Section: Injury Criteria Applied To Seat Comparison Testsmentioning

confidence: 99%