Pitfalls in the CT diagnosis of atlantoaxial rotary subluxation

Kowalski, HM; Cohen, W A; Cooper, Philip; Wisoff, Jeffrey H.

doi:10.2214/ajr.149.3.595

Cited by 77 publications

(33 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The interpretation of the radiological study is often difficult and complex, especially with children. Cervical rotation resulting from patient attitude in the case of Grisel's syndrome or other clinical conditions can cause radiographic changes that are indistinguishable from rotary atlanto-axial subluxation [8,19,20,30]. Open-mouth radiographs of the upper cervical spine can be made by having the patient rotate their head to each side [15,31], but they are also difficult to interpret [8,15].…”

Section: Discussionmentioning

confidence: 99%

Preliminary CT study of C1-C2 rotational mobility in normal subjects

Villas

Arriagada

1999

European Spine Journal

View full text Add to dashboard Cite

IntroductionOnly in neutral position is the caudal surface of the atlas (C1) articular processes in full contact with its corresponding opposite in the axis (C2). Therefore, any rotational displacement of C1 on C2 should result in some degree of contact loss between the corresponding articular surfaces.The classical concepts about atlanto-axial (C1-C2) mechanics give a 40°rotation to both the left and right [29,30], so we can expect that a normal full rotation implies a wide articular surface contact loss. Nevertheless, not only is there no image representing this "expected fact" in classical literature, but it is simply indicated by means of circular arrows [30] upon an anatomical schematic model representing a lateral view of C1 on C2 in neutral position. White and Panjabi [30] show a contact loss between the opposing surfaces of the C1 and C2 articular processes (with no mention of it) when trying to demonstrate the possibly troublesome lengthening that the vertebral artery undergoes when nearing its rotational limits. Furthermore, we have also found a paper showing images in which the previously mentioned surface contact loss can be seen when explaining another altogether different topic [16].The paper by Fielding and Hawkins [8, 9] on atlantoaxial rotatory fixation has become a classic one and it is constantly referred to in almost all published papers relatAbstract A CT study of normal atlanto-axial (C1-C2) rotary mobility was carried out on ten normal immature subjects. In order to determine the limits of normality, the ten children underwent clinical and radiological examination. The clinical study included checking for objective signs of joint laxity and measurement of rotational neck mobility. The radiological study included standard lateral radiographs in neutral and maximal flexion positions and a CT scan taken in maximal left and right side rotation at the C1-C2 articular processes joint. The superpositioning of the images taken in every rotational direction showed, in all ten children, a wide contact loss between the C1-C2 corresponding facets, ranging from 74 to 85% of the total articular surface. The report on these images, carried out by three independent radiologists, concluded that there was a rotary subluxation in all cases. In the ten children studied, there were no significant differences with regard to neck mobility or laxity signs in clinical or standard X-ray examination. Our results lead us to conclude that, except for complete C1-C2 rotational dislocation with facet interlocking, a CT scan showing a wide -but incomplete -rotational facet displacement is not sufficient to define a status of subluxation. This leads us to perceive that there is a risk of overdiagnosis when evaluating upper cervical spine rotational problems in children. The concept of both rotary C1-C2 fixation and subluxation should be revised.

show abstract

Section: Discussionmentioning

confidence: 99%

Preliminary CT study of C1-C2 rotational mobility in normal subjects

Villas

Arriagada

1999

European Spine Journal

View full text Add to dashboard Cite

show abstract

“…The rotation of the human cervical spine has been studied using different approaches and techniques, both in vivo and in vitro [11][12][13][14][15][16][17][18][19]. Researchers report a mean maximum range of rotation for the head relative to the body of 60-80 to both sides [12][13][14]19,20].…”

Section: Introductionmentioning

confidence: 99%

“…Researchers report a mean maximum range of rotation for the head relative to the body of 60-80 to both sides [12][13][14]19,20]. 50-60% of this movement, or a mean of 30-45, takes place in the atlanto-axial joint (C1-C2) [12][13][14][15][16]20], and the rest is distributed at the lower levels of the cervical column (C2-T1), C0-C1 having only a minor contribution [12][13][14]16,20]. For some individuals, a normal maximum rotation in the atlanto-axial joint of over 50 has been reported [11,13], and Dvorak and co-workers suggest that hypermobility or instability of the occipito-atlanto-axial complex should be suspected if the maximum rotation exceeds 56 at the C1-C2-segment [13].…”

Section: Introductionmentioning

confidence: 99%

“…Atlanto-axial fixation may occur with subluxation or dislocation of the atlantoaxial complex, but it may also occur within what is believed to be the vertebras normal range of motion [18,21]. According to Kowalski et al, it is virtually impossible to distinguish radiographically the physiological rotation between the atlas and the axis that occurs in the normal rotation of the head from the pathological subluxations in torticollis and atlanto-axial fixation [15].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Atlanto-axial rotatory subluxations in postmortem CT: Radiologists be aware of a common pitfall

Persson

Falk

Berge

et al. 2013

Forensic Science International

View full text Add to dashboard Cite

The aim of the present study was to determine the frequency of atlanto-axial rotatory subluxations (AARS) in multi detector computed tomography (MDCT) performed on human corpses for forensic purposes and to investigate whether these are a physiological postmortem finding or indicate a trauma to the neck region. 80 forensic cases examined with MDCT from November 2003 to March 2007 were included in the study. The study was approved by the regional ethics committee. For each case volumes were rendered and investigated with reference to suspected AARS and any other anomalies of the head and neck region. The rotation of the head as well as in the atlanto-axial joint were measured and occurring AARS were judged according Fielding`s classification. The finding of AARS was correlated to case criteria such as postmortem head rotation, sex, age, cause of death, time since death and further autopsy results. Statistical analysis was performed using Fisher's exact test, Wilcoxon`s rank sums test and Chisquare test with Pearson approximation. 70 % (n=56) of the cases included in the study presented with an AARS. A strong correlation (p<.0001) between suspected AARS and postmortem head rotation was found. Two cases presented with an atlanto-axial rotation greater than the head rotation. One showed an undiscovered lateral dislocation of the atlas, and one an unfused atlas-ring. There was no correlation to any further investigated case criteria. Ipsilateral AARS with head rotation alone does not indicate trauma to the neck. PmCT can substantially support forensic examinations of the skeleton, especially in body regions, which are elaborate to access at autopsy, such as the cervical spine. Isolated AARS (Fielding type I) on pmCT is usually a normal finding associated with ipsilateral head rotation. Atlanto-Axial Rotatory Subluxations in Postmortem CT:Radiologists Be Aware of a common Pitfall. *Manuscript (without author identifiers) Click here to view linked References ABSTRACTThe aim of the present study was to determine the frequency of atlanto-axial rotatory subluxations (AARS) in multi detector computed tomography (MDCT) performed on human corpses for forensic purposes and to investigate whether these are a physiological postmortem finding or indicate a trauma to the neck region. PmCT can substantially support forensic examinations of the skeleton, especially in body regions, which are elaborate to access at autopsy, such as the cervical spine. Isolated AARS (Fielding type I) on pmCT is usually a normal finding associated with ipsilateral head rotation.

show abstract

“…It can then be reconstructed in any plane to give excellent bony 3-dimensional information about the atlanto-axial articulation [7]. Accurate focusing of the radiation beam ensures small radiation doses and protects vital neighbouring organs [8].…”

Section: Introductionmentioning

confidence: 99%