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Wo J, Lv Z, Wang J, Shen K, Zhu H, Liu Y, Huang Y, Sun G, Li Z. Biomechanical Analysis of Cervical Artificial Disc Replacement Using Cervical Subtotal Discectomy Prosthesis. Front Bioeng Biotechnol 2021; 9:680769. [PMID: 34336799 PMCID: PMC8317600 DOI: 10.3389/fbioe.2021.680769] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/11/2021] [Indexed: 01/22/2023] Open
Abstract
Background: Anterior cervical discectomy and fusion (ACDF) sacrifices segmental mobility, which can lead to the acceleration of adjacent segment degeneration. The challenge has promoted cervical artificial disc replacement (CADR) as a substitute for ACDF. However, CADR has revealed a series of new issues that are not found in ACDF, such as hypermobility, subsidence, and wear phenomenon. This study designed a cervical subtotal discectomy prosthesis (CSDP) consisting of a cervical disc prosthesis structure (CDP structure), cervical vertebra fixation structure (CVF structure), link structure, and locking screw, aiming to facilitate motion control and reduce subsidence. The aim of this study was to assess the biomechanics of the CSDP using finite element (FE) analysis, friction-wear test, and non-human primates implantation study. Study Design: For the FE analysis, based on an intact FE C2-C7 spinal model, a CSDP was implanted at C5-C6 to establish the CSDP FE model and compare it with the Prestige LP prosthesis (Medtronic Sofamor Danek, Minneapolis, MN, United States). The range of motion (ROM), bone-implant interface stress, and facet joint force were calculated under flexion extension, lateral bending, and axial rotation. In addition, CSDP was elevated 1 mm to mimic an improper implantation technique to analyze the biomechanics of CSDP errors in the FE model. Moreover, the friction-wear test was conducted in vitro to research CSDP durability and observe surface wear morphology and total wear volume. Finally, the CSDP was implanted into non-human primates, and its properties were evaluated and verified by radiology. Results: In the FE analysis, the ROM of the CSDP FE model was close to that of the intact FE model in the operative and adjacent segments. In the operative segment, the CSDP error FE model increased ROM in flexion extension, lateral bending, and axial rotation. The maximum stress in the CSDP FE model was similar to that of the intact FE model and was located in the peripheral cortical bone region. The facet joint force changes were minimal in extension, lateral bending, and axial rotation loads in CSDP. In the friction-wear test, after the 150-W movement simulation, both the CVF-link-junction and the CDP-link-junction had slight wear. In the CSDP non-human primate implantation study, no subsidence, dislocation, or loosening was observed. Conclusion: In the FE analysis, the biomechanical parameters of the CSDP FE model were relatively close to those of the intact FE model when compared with the Prestige LP FE model. In terms of CSDP error FE models, we demonstrated that the implantation position influences CSDP performance, such as ROM, bone-implant interface stress, and facet joint force. In addition, we performed a friction-wear test on the CSDP to prove its durability. Finally, CSDP studies with non-human primates have shown that the CSDP is effective.
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Affiliation(s)
- Jin Wo
- Department of Orthopedics, First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Zhenjing Lv
- Department of Spine Orthopedics, Guangdong Hospital of Integrated Traditional Chinese and Western Medicine, Foshan, China
| | - Jing Wang
- Department of Neurosurgery, First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Kui Shen
- Department of Orthopedics, First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Haoran Zhu
- Department of Orthopedics, First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Yang Liu
- Department of Orthopedics, First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Yuen Huang
- Department of Rehabilitation, First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Guodong Sun
- Department of Orthopedics, First Affiliated Hospital, Jinan University, Guangzhou, China.,Department of Orthopedics, Fifth Affiliated Hospital, Heyuan Shenhe People's Hospital, Jinan University, Heyuan, China
| | - Zhizhong Li
- Department of Orthopedics, First Affiliated Hospital, Jinan University, Guangzhou, China.,Department of Orthopedics, Fifth Affiliated Hospital, Heyuan Shenhe People's Hospital, Jinan University, Heyuan, China.,Department of Orthopedics, Heyuan People's Hospital, Heyuan Affiliated Hospital of Jinan University, Heyuan, China
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Li M, Liu S, Kong Q, Sun H, Zhang X, Wang G. Incidence and age and gender profiles of hyperplasia in individual cervical vertebrae. J Int Med Res 2016; 44:917-22. [PMID: 27235407 PMCID: PMC5536620 DOI: 10.1177/0300060516645038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 03/28/2016] [Indexed: 11/15/2022] Open
Abstract
Objective To analyze the incidence and age and gender profiles of hyperplasia in individual cervical vertebrae. Methods In this retrospective study, computed tomography three-dimensional reconstruction images of cervical vertebrae from patients with neck discomfort were analyzed for the presence of hyperplasia and compared with age and gender data. Results Scans from a total of 580 patients (352 males, 228 females) were analyzed. The highest incidence of hyperplasia was seen in C2 (25%), followed by C1 (23%), C6 (16%), C5 (15%), C7 (9%), C4 (8%) and C3 (4%). Patients with C2 hyperplasia were the youngest and those with C1 hyperplasia were the second youngest, while patients with C7 hyperplasia were the oldest. Of those with C2, C1 and C7 hyperplasia, males were significantly younger than females, whereas of those with C3, C4, C5 and C6 hyperplasia, females were significantly younger than males. Conclusions Hyperplasia of the cervical spine shows different age and gender profiles among the seven vertebrae. These findings may be helpful for the early recognition of cervical hyperplasia and highlight the importance of protecting the atlanto-axial joint in daily life.
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Affiliation(s)
- Min Li
- School of Medicine, Shandong University, Jinan, Shandong Province, China Department of Radiology, Taian City Central Hospital, Shandong Province, China
| | - Shuyong Liu
- School of Medicine, Shandong University, Jinan, Shandong Province, China Department of Radiology, Taian City Central Hospital, Shandong Province, China
| | - Qingkui Kong
- Department of Radiology, Taian City Central Hospital, Shandong Province, China
| | - Haitao Sun
- Department of Radiology, Taian City Central Hospital, Shandong Province, China
| | - Xia Zhang
- Department of Radiology, Taian City Central Hospital, Shandong Province, China
| | - Guangbin Wang
- School of Medicine, Shandong University, Jinan, Shandong Province, China
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Betsch MW, Blizzard SR, Shinseki MS, Yoo JU. Prevalence of degenerative changes of the atlanto-axial joints. Spine J 2015; 15:275-80. [PMID: 25277533 DOI: 10.1016/j.spinee.2014.09.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 08/06/2014] [Accepted: 09/15/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Degeneration of the atlantodens and atlanto-axial joints is associated with cervical spine pain and may also be associated with an increased risk of dens fracture. However, there is paucity of literature describing the prevalence of specific degenerative changes in the atlantodens and atlanto-axial facet joints. PURPOSE To document age-related degenerative changes of the cervical spine in a large cohort of patients. STUDY DESIGN/SETTING This is a retrospective cohort study. PATIENT SAMPLE Adult trauma patients were admitted to our Level 1 trauma center. OUTCOME MEASURES Osteoarthritis of the atlantodens and atlanto-axial facet joints of the cervical spine and the presence of intraosseous cyst and calcific synovitis, as determined by computed tomography (CT) scans. METHODS We conducted a retrospective study of 1,543 adult trauma patients who received a cervical spine CT scan. The anterior atlantodens joint interval was measured. The presence or absence of intraosseous cysts and calcific synovitis was recorded. Degeneration of the atlantodens and atlanto-axial facet joints at age intervals was quantified. RESULTS The atlantodens interval narrowed linearly with age (R(2)=0.992, p<.001). The prevalence of intraosseous cysts increased exponentially with age from 4.2% to 37.4%, and calcific synovitis increased from 0% to 11.1%. Intraosseous cyst formation generally began in the second and third decades of life and synovitis in the fifth and sixth decades of life. Facet joints also demonstrated age-related changes; however, the rate of degenerative changes was lower than in the atlantodens joint. CONCLUSIONS To our knowledge, this is the first study that documents specific changes of both atlantodens and atlanto-axial facet joints as a function of age in a large cohort of 1,543 patients. These changes increased exponentially with age and may contribute to pain and limitation in motion. In light of our findings and recent studies demonstrating the association between degeneration and dens fracture in elderly, cervical spine radiographs of elderly patients should be carefully assessed for these changes.
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Affiliation(s)
- Marcel W Betsch
- Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, Portland, OR, USA
| | - Sabina R Blizzard
- Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, Portland, OR, USA
| | - Matthew S Shinseki
- Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, Portland, OR, USA
| | - Jung U Yoo
- Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, Portland, OR, USA.
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Sugiura T, Nagamoto Y, Iwasaki M, Kashii M, Kaito T, Murase T, Tomita T, Yoshikawa H, Sugamoto K. In vivo 3D kinematics of the upper cervical spine during head rotation in rheumatoid arthritis. J Neurosurg Spine 2014; 20:404-10. [DOI: 10.3171/2014.1.spine13252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The upper cervical spine is commonly involved in persons with rheumatoid arthritis (RA). Although 2D measurements have long been used in the evaluation of cervical lesions caused by RA, 2D measurements are limited in their effectiveness for detecting subtle and complex morphological and kinematic changes. The purpose of this study was to elucidate the 3D kinematics of the upper cervical spine in RA and the relationship between 3D morphological changes and decreased segmental rotational motion.
Methods
Twenty-five consecutive patients (2 men and 23 women, mean age 63.5 years, range 42–77 years) with RA (the RA group) and 10 patients (5 men and 5 women, mean age 69.9 years, range 57–82 years) with cervical spondylosis and no involvement of the upper cervical spine (the control group) underwent 3D CT of the cervical spine in 3 positions (neutral, 45° head rotation to the left, and 45° head rotation to the right). The segmental rotation angle from the occiput (Oc) to C-2 was calculated for each participant using a voxel-based registration method, and the 3D destruction of articular facets was quantified using the authors' own parameter, the articular facet index.
Results
The segmental rotation angle was significantly smaller at C1–2 and larger at Oc–C1 in the RA group compared with the control group. The degree of the destruction of the articular facet at C-1 and C-2 correlated with the segmental rotation angle.
Conclusions
In vivo 3D kinematics of the upper cervical spine during head rotation in patients with RA were accurately measured, allowing quantification of the degree of joint destruction for the first time. Joint destruction may play an important role in decreasing segmental motion of the upper cervical spine in RA.
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Affiliation(s)
| | - Yukitaka Nagamoto
- 2Department of Orthopaedic Surgery, Osaka National Hospital, Osaka, Japan
| | - Motoki Iwasaki
- 3Orthopaedics, Osaka University Graduate School of Medicine; and
| | - Masafumi Kashii
- 3Orthopaedics, Osaka University Graduate School of Medicine; and
| | - Takashi Kaito
- 3Orthopaedics, Osaka University Graduate School of Medicine; and
| | - Tsuyoshi Murase
- 3Orthopaedics, Osaka University Graduate School of Medicine; and
| | | | - Hideki Yoshikawa
- 3Orthopaedics, Osaka University Graduate School of Medicine; and
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Boszczyk BM, Littlewood AP, Putz R. A geometrical model of vertical translation and alar ligament tension in atlanto-axial rotation. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2012; 21:1575-9. [PMID: 22382726 DOI: 10.1007/s00586-012-2209-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2009] [Accepted: 02/17/2012] [Indexed: 10/28/2022]
Abstract
INTRODUCTION While allowing the greatest range of axial rotation of the entire spine with 40° to each side, gradual restraint at the extremes of motion by the alar ligaments is of vital importance. In order for the ligaments to facilitate a gradual transition from the neutral to the elastic zone, a complex interaction of axial rotation and vertical translation via the biconvex articular surfaces is essential. The aim of this investigation is to establish a geometrical model of the intricate interaction of the alar ligaments and vertical translatory motion of C1/C2 in axial rotation. METHODS Bilateral alar ligaments including the odontoid process and condylar bony entheses were removed from six adult cadavers aged 65-89 years within 48 h of death. All specimens were judged to be free of abnormalities with the exception of non-specific degenerative changes. Dimensions of the odontoid process and alar ligaments were measured. Graphical multiplanar reconstruction of atlanto-axial rotation was done in the transverse and frontal planes for the neutral position and for rotation to 40° with vertical translation of 3 mm. The necessary fibre elongation of the alar ligaments in the setting with and without vertical translation of the atlas was calculated. RESULTS The mean diameter of the odontoid process in the sagittal plane was 10.6 mm (SD 1.1). The longest fibre length was measured from the posterior border of the odontoid enthesis to the posterior border of the condylar enthesis with an average of 13.2 mm (SD 2.5) and the shortest between the lateral (anterior) border odontoid enthesis and the anterior condylar enthesis with an average of 8.2 mm (SD 2.2). In graphical multiplanar reconstruction of atlanto-axial rotation to 40° without vertical translation of C1/C2, theoretical alar fibre elongation reaches 27.1% for the longest fibres, which is incompatible with the collagenous structure of the alar ligaments. Allowing 3 mm caudal translation of C1 on C2 at 40° rotation, as facilitated by the biconvex atlanto-axial joints, reduces alar fibre elongation to 23.3%. CONCLUSION The biconvex configuration of the atlanto-axial joints is an integral feature of the functionality of upper cervical spine as it allows gradual vertical translation of the atlas against the axis during axial rotation, with gradual tensing of the alar ligaments. Vertical translation on its own, however, does not explain the tolerance of the alar ligaments towards the maximum of 40° of rotation and is most likely synergistic with the effects of the coupled motion of occipitocervical extension during rotation.
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Affiliation(s)
- B M Boszczyk
- The Centre for Spinal Studies and Surgery, Queen's Medical Centre, Nottingham University Hospitals, Nottingham, UK.
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Dolinak D. Low Force Fracture of the Odontoid, with Discussion of High Force Cervical Fracture. Acad Forensic Pathol 2012. [DOI: 10.23907/2012.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cervical fracture may occur with a high force mechanism of injury such as a motor vehicle crash, or with a low force mechanism of injury such as a ground level fall. To better characterize and understand low force cervical fractures and their significance, case files from the Travis County Medical Examiner's office covering a 5-year time period were retrospectively reviewed for fatal cervical fracture occurring with an accidental ground level fall. Thirty such fatal cervical fractures were identified, all occurring in elderly individuals (>65 years of age), with odontoid type 2 fracture of the C2 vertebra identified as the most frequent type of fracture. Odontoid fracture should be included in the list of craniocervical injury that may result from not only motor vehicle crashes and other high force mechanisms of injury, but also low force mechanisms of injury such as a ground level fall with head impact in an elderly individual.
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Lakshmanan P, Jones A, Howes J, Lyons K. CT evaluation of the pattern of odontoid fractures in the elderly--relationship to upper cervical spine osteoarthritis. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2005; 14:78-83. [PMID: 15723251 PMCID: PMC3476682 DOI: 10.1007/s00586-004-0743-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 02/23/2004] [Accepted: 04/10/2004] [Indexed: 10/26/2022]
Abstract
Odontoid fractures are common in the elderly following minor falls. Almost all of them have osteoarthritis of the cervical spine below the axis vertebra. As a result, there is increased stress on the spared upper cervical spine, resulting in a higher incidence of injuries. As movement in the upper cervical spine involves participation of five joints, degeneration in any one particular joint may affect the biomechanics of loading of the upper cervical spine. We aimed to analyse the relationship of odontoid fractures to the pattern of upper cervical spine osteoarthritis in the elderly. We studied the CT-scan images of the cervical spine in 23 patients who were over the age of 70 years and had odontoid fractures. In each patient, the type of odontoid fracture and the characteristics of the degenerative changes in each joint were analysed. Twenty-one of 23 patients had Type-II odontoid fractures. The incidence of significant atlanto-odontoid degeneration in these individuals was very high (90.48%), with relative sparing of the lateral atlantoaxial joints. Osteoporosis was found in 13 of 23 patients at the dens-body junction and in seven of 23 patients at the odontoid process and body of the axis. With ageing, progressively more severe degenerative changes develop in the atlanto-odontoid joint. These eventually obliterate the joint space and fix the odontoid to the anterior arch of the atlas. In contrast, the lateral atlantoaxial joints are hardly affected by osteoarthritis. Thus, ultimately, atlantoaxial movements including atlantoaxial rotation are markedly limited by osteoarthritis of the atlanto-odontoid joint. However, there is still potential for movement in the lateral atlantoaxial joints, as they remain relatively free of degenerative change. The vulnerability of the atlantoaxial segment is further increased by markedly limited rotation below the axis vertebra due to severe facet-joint degeneration. As a consequence, a relatively low-energy trauma to the lateral part of the face, for instance by a fall, will induce forced atlantoaxial rotation. This, with the marked limitation of movement at the atlanto-odontoid joint, will produce a torque force at the base of the odontoid process leading to a Type II fracture.
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Affiliation(s)
- Palaniappan Lakshmanan
- Department of Trauma and Orthopaedics, University Hospital Of Wales and Llandough Hospital, Cardiff, UK.
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Hong-Wan N, Ee-Chon T, Qing-Hang Z. Biomechanical effects of C2-C7 intersegmental stability due to laminectomy with unilateral and bilateral facetectomy. Spine (Phila Pa 1976) 2004; 29:1737-45; discussion 1746. [PMID: 15303016 DOI: 10.1097/01.brs.0000134574.36487.eb] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN The biomechanical responses resulting from laminectomy with graded unilateral and bilateral facetectomy were quantified using a three-dimensional nonlinear finite element model of the C2-C7 motion segments. OBJECTIVE To study the influence of laminectomy with graded unilateral and bilateral facetectomy on the cervical spinal biomechanics. SUMMARY OF BACKGROUND DATA Cervical spinal stenosis is a condition that is caused by the narrowing of the spinal canal. Laminectomy and facetectomy are commonly used surgical procedures for decompressing cervical spinal stenosis. Resection of the posterior structures causes instability and affects the internal stresses of the cervical spinal components. However, the influence of these surgical procedures on the biomechanical responses of the cervical spine has not been studied. METHODS A nonlinear finite element model of the intact C2-C7 was constructed and validated. Ten surgically altered models were created from the intact model and were tested under physiologic loading. Because of the inclusion of five motion segments, it was possible to determine the intersegmental responses and internal cortical shell and disc stresses in the adjacent altered and unaltered spinal components. RESULTS Under combined flexion and extension, intersegmental motions at C4-C5 and C5-C6 increased significantly after C5 laminectomy. Subsequent facetectomy performed at C5 and C6 on the laminectomized model only affected the responses at the C5-C6 segment. Overall, slight intersegmental responses of up to 5% were observed at the adjacent levels of C3-C4 and C6-C7. Laminectomy did not cause any significant increase in the intersegmental motions under lateral bending and axial rotation. Extending the surgical procedures to unilateral and bilateral facetectomy only increased the intersegmental motions slightly. Similar increases in the intervertebral disc and the cortical shell stresses were observed. These findings may partially explain the clinical observations of enhanced osteophytes formation. CONCLUSIONS This study provides a better understanding of the surgically altered cervical spinal biomechanics and may help formulate treatment strategies such as spinal implants.
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Affiliation(s)
- Ng Hong-Wan
- School of Mechanical and Production Engineering, Nanyang Technological University, Singapore.
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10
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Lin RM, Tsai KH, Chu LP, Chang PQ. Characteristics of sagittal vertebral alignment in flexion determined by dynamic radiographs of the cervical spine. Spine (Phila Pa 1976) 2001; 26:256-61. [PMID: 11224861 DOI: 10.1097/00007632-200102010-00010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN This study was conducted to depict the change patterns of intervertebral motion of the cervical spine during flexion, upright, and extension positions using dynamic radiographs. Special interest was focused on the flexion position. OBJECTIVES To find reliable criteria for judging the normal intervertebral flexibility based on a survey of the normal population. METHODS The lateral dynamic radiographs of 75 normal subjects were analyzed by digitization and computer calculation. The characteristics of intervertebral positions were investigated using flexion radiographs. RESULTS From extension to flexion, the angles of intervertebral angular displacement changed from lordosis with different degrees to nearly 0 degrees, which means the adjacent endplates are almost parallel, except at C1-C2; the intervertebral translation changes from slightly retrolisthetic to zero displacement. Using C2-C3 as a baseline to calculate the intervertebral differences of angular displacement and translation in flexion radiographs, nearly all the intervertebral differences of angular displacement were less than 7 degrees, and those of translation were less than 0.06 mm. CONCLUSIONS Qualitative changes from extension to flexion and quantitative values of intervertebral differences in flexion radiographs help define the normal flexibility of the cervical spine more accurately.
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Affiliation(s)
- R M Lin
- Department of Orthopedics, College of Medicine, National Taiwan University, Taipei, Taiwan.
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Castro WH, Sautmann A, Schilgen M, Sautmann M. Noninvasive three-dimensional analysis of cervical spine motion in normal subjects in relation to age and sex. An experimental examination. Spine (Phila Pa 1976) 2000; 25:443-9. [PMID: 10707389 DOI: 10.1097/00007632-200002150-00009] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Experimental examination in vivo. OBJECTIVES To determine the precision of the ultrasound-based Coordinate Measuring System (CMS 50; Zebris Medizintechnik GmbH, D-88316, Isny, Germany) and then to establish a reference range for the active range of motion of the cervical spine in normal test subjects grouped according to age and sex. SUMMARY OF BACKGROUND DATA Many different devices such as inclinometers, goniometers, potentiometers, computer-aided devices, and radiographic procedures have been developed to examine the range of motion of the cervical spine. All of them have more or less inherent limitations. METHODS To assess the precision of this examination method, preliminary experiments were performed including intraobserver retest and two-observer repeatability, intraindividual variability, a daily profile, and a comparison between active and passive motions. In the subsequent main experiment 157 persons (86 women and 71 men) were examined during active motion. The sex groups were further subdivided into age groups of 10 years each. A comparison of weight and athletic activity was also performed. RESULTS The range of motion decreased with increasing age, increasing body weight, and decreasing athletic activity. The rotation in the upper cervical spine increases with age to compensate for the reduced range of motion in the lower levels. Women showed significantly better mobility than men of the same age, only above the age of 70. CONCLUSIONS The CMS 50 device provides precise reproducible measurements of the active range of motion of the cervical spine in all three planes. Criteria such as age, sex, body weight, and athletic activity influence the range of motion of the cervical spine.
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Affiliation(s)
- W H Castro
- Akademie für Manuelle Medizin an der Westfälischen Wilhelms-Universität Münster, Germany
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Duerinckx AJ, Yu WD, El-Saden S, Kim D, Wang JC, Sandhu HS. MR imaging of cervical spine motion with HASTE. Magn Reson Imaging 1999; 17:371-81. [PMID: 10195580 DOI: 10.1016/s0730-725x(98)00176-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The HASTE (half-Fourier acquisition single-shot turbo spin-echo) technique delivers images with T2-weighting in about half a second and could be ideal for fast dynamic studies when T2-weighting is needed. We evaluated cardiac-triggered HASTE to study cervical spine flexion/extension. The cervical spines of ten asymptomatic volunteers were studied during flexion/extension motion on a 1.5 Tesla imager using a cardiac triggered version of the HASTE technique. Midline sagittal images were acquired every 2 to 3 s during neck flexion and extension. Image quality was compared to traditional T2-weighted Turbo spin-echo. The study duration per flexion/ extension was typically less than 20 seconds and well tolerated. The cardiac-gated T2-weighted HASTE images compared favorably to the traditional T2-weighted TSE images in quality and overall anatomic detail. Range of motion averaged: flexion 30 degrees (range 8 degrees -48 degrees) and extension 23 degrees (range 0 degrees -57 degrees ). Greatest motion occurred in the lower cervical spine (C4-C7). At the intervertebral discs the canal diameter, anterior and posterior CSF spaces were widest in neutral position and decreased with flexion and extension. Therefore, Cardiac-gated T2 HASTE sequences provide diagnostic and time-efficient dynamic MR images of cervical spine motion.
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Affiliation(s)
- A J Duerinckx
- Radiology Service, VA Medical Center, West Los Angeles, CA 90073, USA.
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Lu J, Ebraheim NA, Yang H, Heck BE, Yeasting RA. Anatomic considerations of anterior transarticular screw fixation for atlantoaxial instability. Spine (Phila Pa 1976) 1998; 23:1229-35; discussion 1236. [PMID: 9636976 DOI: 10.1097/00007632-199806010-00011] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
STUDY DESIGN Anatomic parameters of C1 and C2 were measured in 30 dried human cervical spines. Anterior transarticular C1-C2 screws were placed in 15 cadaveric spines. OBJECTIVE To provide anatomic data for anterior transarticular atlantoaxial screw or C1-C2 screw and plate fixation. SUMMARY OF BACKGROUND DATA A posterior approach to fixation in the atlantoaxial joint has been well described. Damage to the vertebral artery is documented as a rare complication of posterior atlantoaxial transarticular screw fixation. An anterior surgical approach to exposing the upper cervical spine for internal fixation and bone graft recently has been developed. No anatomic information regarding the anterior transarticular atlantoaxial screw or screw and plate fixation between C1 and C2 is available in the literature. METHODS Direct measurements using digital calipers and a goniometer were taken from 30 pairs of dried human C1 and C2 vertebrae. The anterior transarticular C1-C2 screw insertion point is at the junction of the lateral edge of the C2 vertebral body to 4 mm above the inferior edge of the C2 anterior arch. The parameters related to anterior transarticular atlantoaxial screw fixation or screw and plate fixation between the C1 lateral mass and the C2 vertebral body were measured. Fifteen embalmed cadavers were used for anterior C1-C2 transarticular screw placement. Longer screws (30-40 mm) were used to detect whether the screw tips violated the upper cervical canal or vertebral arteries. RESULTS In the anterior transarticular atlantoaxial screw placement, lateral angulation of the screw placement relative to sagittal plane ranged from 4.8 +/- 1.8 degrees to 25.3 +/- 2.6 degrees. The posterior angulation of the screw placement relative to the coronal plane ranged from 12.8 +/- 3.1 degrees to 22.6 +/- 3.2 degrees. The length of the medial screw path ranged from 14.7 +/- 1.5 mm to 25.4 +/- 2.8 mm. In the anterior screw and plate fixation, the anteroposterior diameter of the inferior facet articular surface ranged from 16.2 +/- 1.6 mm to 17.1 +/- 1.8 mm. The anteroposterior diameter of the C2 vertebral body ranged from 9.3 +/- 1 mm to 16.2 +/- 1.8 mm. The anterior prevascular retropharyngeal approach appropriately exposed the atlantoaxial joint for anterior transarticular C1-C2 screw placement. No screws violated the vertebral artery and cervical canal. CONCLUSIONS An anterior transarticular atlantoaxial screw 15-25 mm long can be inserted with a lateral angulation of 5-25 degrees relative to the sagittal plane and a posterior angulation of 10-25 degrees relative to the coronal plane. Additionally, in C1-C2 anterior plate fixation screws 15 mm long could be anchored in the inferior facet of the C1, and screws 9-15 mm long could be anchored in the C2 vertebral body.
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Affiliation(s)
- J Lu
- Department of Orthopaedic Surgery, Medical College of Ohio, Toledo, USA
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Dumas JL, Salama J, Dreyfus P, Thoreux P, Goldlust D, Chevrel JP. Magnetic resonance angiographic analysis of atlanto-axial rotation: anatomic bases of compression of the vertebral arteries. Surg Radiol Anat 1996; 18:303-13. [PMID: 8983110 DOI: 10.1007/bf01627609] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The aim of this study was to identify the functional anatomic factors involved in the maintenance or disturbance of flow in the vertebral aa. during atlanto-axial rotation. Fourteen healthy volunteers were studied by magnetic resonance angiography (MRA) by a three-dimensional sequence in phase contrast centered on the vertebral aa. at the level of the cranio-cervical junction before and after left rotation of the head. A decrease in the signal intensity of the arterial flow was sought for. The results were compared to the posterolateral development of the loop of the vertebral a. in its atlanto-axial segment in neutral position, and to the measurement of the angular opening between the atlas and axis in dynamic position. Seven subjects also had a three-dimensional CT study (3D CT) of the bony relations of C1 and C2 after rotation. In 4 subjects a disturbance of flow in the right vertebral a. was observed in the transverse foramen of C2. This occurred when two factors were combined: an under-developed atlanto-axial arterial loop and a C1-C2 angle exceeding 35 degrees in maximal rotation. In the other subjects a well-developed arterial loop and/or a C1-C2 angle of less than 35 degrees in maximal rotation were factors preserving the arterial flow. The risk factor associated with the C1-C2 angle seemed correlated in 3D CT with loss of the usual asymmetric character of rotation. A clinical application is reported with a case combining chronic rotational dysfunction of the cranio-cervical junction as shown by 3D CT and complete compression of the vertebral a. in MRA, confirmed by conventional angiography. A knowledge of this physiopathologic mechanism allows clinical detection and evaluation of the risk of any effect of pathology of the cranio-cervical junction on the vertebral a.
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Affiliation(s)
- J L Dumas
- Institut d'Anatomie Clinique, UFR de Bobigny, Université de Paris Nord, France
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Abstract
The biomechanical characteristics of four different methods of C1-2 cable fixation were studied to assess the effectiveness of each technique in restoring atlantoaxial stability. Biomechanical testing was performed on the upper cervical spines of four human cadaveric specimens. Physiological range loading was applied to the atlantoaxial specimens and three-dimensional motion was analyzed with stereophotogrammetry. The load-deformation relationships and kinematics were measured, including the stiffness, the angular ranges of motion, the linear ranges of motion, and the axes of rotation. Specimens were nondestructively tested in the intact state, after surgical destabilization, and after each of four different methods of cable fixation. Cable fixation techniques included the interspinous technique, the Brooks technique, and two variants of the Gallie technique. All specimens were tested immediately after fixation and again after the specimen was fatigued with 6000 cycles of physiological range torsional loading. All four cable fixation methods were moderately flexible immediately; the different cable fixations allowed between 5 degrees and 40 degrees of rotational motion and between 0.6 and 7 mm of translational motion to occur at C1-2. The Brooks and interspinous methods controlled C1-2 motion significantly better than both of the Gallie techniques. The motion allowed by one of the Gallie techniques did not differ significantly from the motion of the unfixed destabilized specimens. All cable fixation techniques loosened after cyclic loading and demonstrated significant increases in C1-2 rotational and translational motions. The bone grafts shifted during cyclic loading, which reduced the effectiveness of the fixation. The locations of the axes of rotation, which were unconstrained and mobile in the destabilized specimens, became altered with cable fixation. The C1-2 cables constrained motion by shifting the axes of rotation so that C-1 rotated around the fixed cable and graft site. After the specimen was fatigued, the axes of rotation became more widely dispersed but were usually still localized near the cable and graft site. Adequate healing requires satisfactory control of C1-2 motion. Therefore, some adjunctive fixation is advocated to supplement the control of motion after C1-2 cable fixation (that is, a cervical collar, a halo brace, or rigid internal fixation with transarticular screws).
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Affiliation(s)
- C A Dickman
- Spinal Biomechanics Research Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
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Dickman CA, Crawford NR, Brantley AG, Sonntag VK. Biomechanical effects of transoral odontoidectomy. Neurosurgery 1995; 36:1146-52; discussion 1152-3. [PMID: 7643995 DOI: 10.1227/00006123-199506000-00013] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The acute biomechanical effects of transoral odontoidectomy were studied by using qualitative and quantitative methods to assess atlantoaxial motion. In vitro biomechanical testing was performed on the upper cervical spines of eight baboon and five human cadaveric specimens. Using an unconstrained testing apparatus, we performed a flexibility method of testing. Physiological range loading was applied to atlantoaxial specimens, and three-dimensional motion was analyzed with stereophotogrammetry. Force-deformation relationships were delineated in intact specimens and again after surgical removal of the anterior C1 arch, odontoid process, and transverse atlantal ligament. We studied the total range of rotational and linear motions, the behavior of the neutral zone and elastic zone, the flexibility coefficients, and the instantaneous axes of rotation during flexion, extension, bilateral lateral bending, and bilateral axial rotation. Odontoidectomy produced several distinct alterations in motion and in force-deformation responses at C1-C2 that were almost identical in the baboon and human specimens. After odontoidectomy, the atlas developed significantly increased translational movements, which were most prominent in the anteroposterior direction. The total angular range of motion increased significantly during flexion, extension, and lateral bending but not during axial rotation. When the total range of motion was altered, the neutral zone was affected selectively and the elastic zone was spared. Surgery produced mobile, widely spread, unconstrained instantaneous axes of rotation that were in a constrained, fixed position in intact specimens. Clinically, transoral odontoidectomy may predispose patients to spinal instability. Even if acute spinal instability is not apparent, the patients may be susceptible to the delayed effects of the surgery because of the altered anatomy and biomechanical responses.
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Affiliation(s)
- C A Dickman
- Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
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