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Spine Nov 2014In vitro biomechanical study.
STUDY DESIGN
In vitro biomechanical study.
OBJECTIVES
To investigate mechanisms of odontoid fracture.
SUMMARY OF BACKGROUND DATA
Odontoid fractures in younger adults occur most often due to high-energy trauma including motor vehicle crashes and in older adults due to fall from standing height.
METHODS
Horizontally aligned head impacts into a padded barrier were simulated using a human upper cervical spine specimen (occiput through C3) mounted to a surrogate torso mass on a sled and carrying a surrogate head. We divided 13 specimens into 3 groups on the basis of head impact location: upper forehead in the midline, upper lateral side of the forehead, and upper lateral side of the head. Post-impact fluoroscopy and anatomical dissection documented the injuries. Time-history biomechanical responses were determined.
RESULTS
Four of the 5 specimens subjected to impact to the upper forehead in the midline sustained type II or high type III odontoid fractures due to abrupt deceleration of the head and continued forward torso momentum. Average peak force reached 1787.1 N at the neck at 50.3 milliseconds. Subsequently, the motion peaks occurred for the head relative to C3 reaching 15.2° for extension, 2.1 cm for upward translation, and 5.3 cm for horizontal compression, between 62 and 68 milliseconds.
CONCLUSION
We identified impact to the upper forehead in the midline as a mechanism that produced odontoid fracture and associated atlas and ligamentous injuries similar to those observed in real-life trauma. We were not able to create odontoid fractures during impacts to the upper lateral side of the forehead or upper lateral side of the head. Dynamic odontoid fracture was caused by rapid deceleration of the head, which transferred load inferiorly combined with continued torso momentum, which caused spinal compression and anterior shear force and forward displacement of the axis relative to the atlas.
Topics: Aged, 80 and over; Biomechanical Phenomena; Cadaver; Cervical Vertebrae; Craniocerebral Trauma; Deceleration; Dissection; Female; Fluoroscopy; Forehead; Fractures, Bone; Head; Humans; Male; Motion; Odontoid Process; Torso
PubMed: 25271495
DOI: 10.1097/BRS.0000000000000609 -
Clinical Spine Surgery Dec 2017Evidence-based systematic review. (Review)
Review
STUDY DESIGN
Evidence-based systematic review.
OBJECTIVES
To define the optimal treatment of fractures involving the C2 body, including those with concomitant injuries, based upon a systematic review of the literature.
SUMMARY OF BACKGROUND DATA
Axis body fractures have customarily been treated nonoperatively, but there are some injuries that may require operative intervention. High-quality literature is sparse and there are few class I or class II studies to guide treatment decisions.
MATERIALS AND METHODS
A literature search was conducted using PubMed (MEDLINE), Cochrane Central Register of Controlled Trials, and Scopus (EMBASE, MEDLINE, COMPENDEX). The quality of literature was rated according to a grading tool developed by the Center for Evidence-based Medicine. Operative and nonoperative treatment of axis body fractures were compared using fracture bony union as the primary outcome measure. As risk factors for nonunion were not consistently reported, cases were analyzed individually.
RESULTS
The literature search identified 62 studies, of which 10 were case reports which were excluded from the analysis. A total of 920 patients from 52 studies were included. The overall bony union rate for all axis body fractures was 91%. Although the majority of fractures were treated nonoperatively, there has been an increasing trend toward operative intervention for Benzel type III (transverse) axis body fractures. Nearly 76% of axis body fractures were classified as type III fractures, of which 88% united successfully. Nearly all Benzel type I and type II axis body fractures were successfully treated nonoperatively. The risk factors for nonunion included: a higher degree of subluxation, fracture displacement, comminution, concurrent injuries, delay in treatment, and older age.
CONCLUSIONS
High rates for fracture union are reported in the literature for axis body fractures with nonoperative treatment. High-quality prospective studies are required to develop consensus as to which C2 body fractures require operative fixation.
Topics: Axis, Cervical Vertebra; Databases, Bibliographic; Fracture Fixation; Fractures, Bone; Humans; Longitudinal Studies
PubMed: 29176489
DOI: 10.1097/BSD.0000000000000309 -
Neurospine Jun 2019To describe the biomechanically relevant anatomy of the Axis vertebra and the load transfer patterns within the bone, and on that basis, to postulate its mechanism of...
To describe the biomechanically relevant anatomy of the Axis vertebra and the load transfer patterns within the bone, and on that basis, to postulate its mechanism of injury, a literature review was conducted of the anatomy and biomechanics of Axis fractures. Two hypotheses have been presented: the internal gear hypothesis and the leaf spring hypothesis. Both are based on the trabecular anatomy of the vertebra and its load transmission patterns. The relationship of the Axis with Hangman's injury is also discussed. According to the leaf spring hypothesis, the C2 pedicle corresponds to the shackle in the assembly and constitutes the weak link. The trabecular architecture of the Axis is such that the primary compression of the trabeculae is directed from the superior facet to the C2-3 endplate, with few trabeculae directed to the inferior facet. Along with the trabecular void in this area, this renders the isthmus vulnerable to trauma. The isthmus of the Axis is biomechanically susceptible to injury due to its unique anatomy in relation to the whole cervical spine and the internal load transmission patterns of the bone. The author suggests that in the flexion type of Hangman's injury, the C1-2 posterior ligaments are disrupted and need to be addressed.
PubMed: 31261461
DOI: 10.14245/ns.1938140.070 -
Ugeskrift For Laeger Feb 2020This review summarises the present, limited, knowledge of os odontoideum (OO). The prevalence is unknown, and the aetiology is widely debated, though irrelevant to... (Review)
Review
This review summarises the present, limited, knowledge of os odontoideum (OO). The prevalence is unknown, and the aetiology is widely debated, though irrelevant to management of the disease. Surgery of symptomatic patients is advocated, as there is more uncertainty about the treatment of asymptomatic patients. Diagnosis is obtained with plain X-ray. However, nowadays MRI and CT scanning are recommended for further clarification and judgement of the severity. Knowledge of OO is important to minimise misjudgement and consequently inappropriate treatment. It is recommended, that patients are examined by highly specialised spine doctors before further cervical manipulation due to the high risk of instability with potentially severe consequences.
Topics: Axis, Cervical Vertebra; Humans; Magnetic Resonance Imaging; Odontoid Process; Quadriplegia; Tomography, X-Ray Computed
PubMed: 32138818
DOI: No ID Found -
Zhongguo Gu Shang = China Journal of... Sep 2017Upper cervical fracture-dislocations are series of pathological injuries occurred in occipital, atlas and axis caused by traumatic impact, which often results in severe... (Review)
Review
Upper cervical fracture-dislocations are series of pathological injuries occurred in occipital, atlas and axis caused by traumatic impact, which often results in severe clinical consequences, such as paraplegia, quadriplegia, and even death. In light of the potential severe clinical outcomes, it is important to define the type of upper cervical fracture-dislocations depending on which the clinician can deal with the disease properly. Owing to its specific anatomical structures, the upper cervical fractures occurr to the unique osseous structures or ligamentous connections always present in predictable patterns. Common fracture include occipital condylar fracture, atlanto-occipital dislocation, atlas fracture, and the three types of fractures of axis, including odontoid fracture, Hangman's fracture and axis body fracture. In this paper we will review the literatures about the classification and management of upper cervical fracture, to help the clinicians to treat their patients better.
Topics: Axis, Cervical Vertebra; Cervical Atlas; Cervical Vertebrae; Humans; Joint Dislocations; Occipital Bone; Spinal Fractures
PubMed: 29455493
DOI: 10.3969/j.issn.1003-0034.2017.09.018 -
Neuro-Chirurgie May 2024An in-depth understanding of the anatomy of the craniocervical junction (CCJ) is indispensable in skull base neurosurgery. In this paper, we discuss the osteology of the... (Review)
Review
An in-depth understanding of the anatomy of the craniocervical junction (CCJ) is indispensable in skull base neurosurgery. In this paper, we discuss the osteology of the occipital bone, the atlas (C1) and axis (C2), the ligaments and the muscle anatomy of the CCJ region and their relationships with the vertebral artery. We will also discuss the trajectory of the vertebral artery and review the anatomy of the jugular foramen and lower cranial nerves (IX to XII). The most important surgical approaches to the CCJ, including the far lateral approach, the anterolateral approach of Bernard George and the endoscopic endonasal approach, will be discussed to review the surgical anatomy.
Topics: Humans; Skull Base; Cervical Atlas; Occipital Bone; Atlanto-Occipital Joint; Vertebral Artery; Neurosurgical Procedures; Cervical Vertebrae; Atlanto-Axial Joint; Cranial Nerves; Axis, Cervical Vertebra
PubMed: 38277861
DOI: 10.1016/j.neuchi.2023.101511 -
Spine Aug 2019
Topics: Aged; Fractures, Bone; Humans; Odontoid Process
PubMed: 31335791
DOI: 10.1097/BRS.0000000000003105 -
Ortopedia, Traumatologia, Rehabilitacja Oct 2023Odontoid fractures are found in two age groups. In younger patients, they occur following traffic accidents, falls from a height and during sports. In older patients...
BACKGROUND
Odontoid fractures are found in two age groups. In younger patients, they occur following traffic accidents, falls from a height and during sports. In older patients with poor bone quality, they are usually caused by falls from one's own height. Most fractures are stable and do not require surgical treatment. Unstable, severely displaced fractures with neurological deficits require surgical treatment. The aim of the study was to evaluate the surgical and functional outcomes of treatment of odontoid fractures with a cannulated screw.
MATERIALS AND METHODS
The study enrolled 20 patients that underwent surgery in the years 2020-2022. The patients were divided into two groups: below 60 (group A) and over 60 years of age (group B). Patients were assessed at one day pre-op, one day post-op, 6 weeks following surgery and 3 months following surgery. Imaging studies were performed to assess the angulation and degree of displacement of bone fragments. After the fracture was surgically fixed with a cannulated screw, bone union and the stability of fracture fixation were assessed. Preoperative and postoperative pain intensity as per a VAS, functional status assessed with the NDI questionnaire, quality of life (EQ-VAS) and neurological status (ASIA scale) were compared.
RESULTS
Good functional and surgical results were obtained in both groups of patients. Performance and quality of life improved, while pain intensity decreased in all patients. In 3 patients with post-traumatic paresis, the dysfunctions gradually subsided. No general medical or perioperative complications were observed. Bone union of the fracture was achieved in 40% of patients in group B and in 80% in group A. Achieving union did not determine the functional status of patients. On functional radiographs, all places of fixation were stable.
CONCLUSIONS
1. Odontoid fracture fixation with a single cannulated screw is a safe method of treatment. It provided a high union rate and good stability of the fracture. 2. Fracture non-union was noted more often in the group of older patients, but it did not negatively impact quality of life and performance.
Topics: Humans; Middle Aged; Aged; Odontoid Process; Spinal Fractures; Quality of Life; Fracture Fixation, Internal; Fractures, Bone; Treatment Outcome; Retrospective Studies
PubMed: 38088099
DOI: 10.5604/01.3001.0053.9673 -
JBJS Reviews Aug 2019
Review
Topics: Aged; Bone Screws; Female; Humans; Male; Middle Aged; Odontoid Process; Orthopedic Procedures; Spinal Fractures; Tomography, X-Ray Computed
PubMed: 31389849
DOI: 10.2106/JBJS.RVW.18.00122 -
European Journal of Orthopaedic Surgery... Apr 2018The thorough knowledge of C2 lamina anatomy is essential for the avoidance of complications during screw fixation. We performed a review of the literature, aiming to... (Review)
Review
PURPOSE
The thorough knowledge of C2 lamina anatomy is essential for the avoidance of complications during screw fixation. We performed a review of the literature, aiming to detect what was found about anatomical feasibility of C2 translaminar fixation in different populations, along with possible recommendations for the avoidance of complications, and to detect whether factors such as race or gender could influence axis lamina anatomy and fixation feasibility.
METHODS
We performed a search in PubMed and Cochrane database of systematic reviews for studies which correlated axis lamina anatomy with fixation feasibility. We extracted data concerning measurements on C2 lamina, the methods and conclusions of the studies.
RESULTS
Twenty-six studies met our inclusion criteria. The studies mainly focused on Asian populations. Male gender was generally related to larger anatomical parameters of C2 lamina. The use of a C2 translaminar screw with a diameter of 3.5 mm was generally feasible, even in children, but there was disagreement about risk of vertebral artery injury. Computed tomography was most frequently recommended preoperatively. Three-dimensional reconstruction was suggested by some authors.
CONCLUSION
C2 lamina anatomy generally permitted screw fixation in most studies, but there was disagreement about risk of vertebral artery injury. Preoperative computed tomography was generally recommended, while, according to some authors, three-dimensional reconstruction could be essential. However, there is a relative lack of studies about non-Asian populations. More research could further illustrate the anatomy of C2 lamina, clarify the safety of axis fixation for more populations and perhaps modify preoperative imaging protocols.
Topics: Axis, Cervical Vertebra; Bone Screws; Feasibility Studies; Humans; Orthopedic Procedures; Postoperative Care; Prosthesis Implantation; Sex Factors; Tomography, X-Ray Computed
PubMed: 29119372
DOI: 10.1007/s00590-017-2072-z