Measurement of Occipitocervical Angle

Shoda, Naoki; Takeshita, Katsushi; Seichi, Atsushi; Akune, Toru; Nakajima, Susumu; Anamizu, Yorito; Nakamura, Kozo

doi:10.1097/00007632-200405150-00022

Cited by 34 publications

(21 citation statements)

References 22 publications

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“…The absolute value of the O-C2A in a neutral position varies between individuals, and any change from this position is important clinically [9,12,13]. The impact of the O-C2A on the oropharyngeal space and D/D after the O-C fusion has been demonstrated from several directions [8][9][10], and the present study reconfirms it clearly from another perspective.…”

Section: Discussionsupporting

confidence: 81%

The O-C2 angle established at occipito-cervical fusion dictates the patient’s destiny in terms of postoperative dyspnea and/or dysphagia

et al. 2013

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Purpose We have revealed that the cause of postoperative dyspnea and/or dysphagia after occipito-cervical (O-C) fusion is mechanical stenosis of the oropharyngeal space and the O-C2 alignment, rather than total or subaxial alignment, is the key to the development of dyspnea and/or dysphagia. The purpose of this study was to confirm the impact of occipito-C2 angle (O-C2A) on the oropharyngeal space and to investigate the chronological impact of a fixed O-C2A on the oropharyngeal space and dyspnea and/or dysphagia after O-C fusion. Materials and methods We reviewed 13 patients who had undergone O-C2 fusion, while retaining subaxial segmental motion (OC2 group) and 20 who had subaxial fusion without O-C2 fusion (SA group). The O-C2A, C2-C6 angle and the narrowest oropharyngeal airway space were measured on lateral dynamic X-rays preoperatively, when dynamic X-rays were taken for the first time postoperatively, and at the final follow-up. We also recorded the current dyspnea and/or dysphagia status at the final followup of patients who presented with it immediately after the O-C2 fusion.Results There was no significant difference in the mean preoperative values of the O-C2A (13.0 ± 7.5 in group OC2 and 20.1 ± 10.5 in group SA, Unpaired t test, P = 0.051) and the narrowest oropharyngeal airway space (17.8 ± 6.0 in group OC2 and 14.9 ± 3.9 in group SA, Unpaired t test, P = 0.105). In the OC2 group, the narrowest oropharyngeal airway space changed according to the cervical position preoperatively, but became constant postoperatively. In contrast, in the SA group, the narrowest oropharyngeal airway space changed according to the cervical position at any time point. Three patients who presented with dyspnea and/or dysphagia immediately after O-C2 fusion had not resolved completely at the final follow-up. The narrowest oropharyngeal airway space and postoperative dyspnea and/or dysphagia did not change with time once the O-C2A had been established at O-C fusion. Conclusions The O-C2A established at O-C fusion dictates the patient's destiny in terms of postoperative dyspnea and/or dysphagia. Surgeons should pay maximal attention when establishing the O-C2A during surgery, because their careless decision for the O-C2A may cause persistent dysphagia or a life-threatening consequence. We recommend that the O-C2A in O-C fusion should be kept at least at more than the preoperative O-C2A in the neutral position.

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Section: Discussionsupporting

confidence: 81%

The O-C2 angle established at occipito-cervical fusion dictates the patient’s destiny in terms of postoperative dyspnea and/or dysphagia

et al. 2013

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“…We have chosen to use the McGregor line for its sensitivity and interobserver reproducibility [14]. In literature, there are many reports evaluating the occipitoaxial angle and its relation to the clinical outcome, but many of this papers are not comparable because of the different methods of investigation used [10,13].…”

Section: Discussionmentioning

confidence: 99%

“…The study here proposed is based on the relationship between the clinical outcome and the occipitocervical fusion angle. Occipitocervical angle in healthy adults, measured using the McGregor line, is about 15°in lordosis [9,14], varying from 5°to 30°depending on the sex and age. Philips et al [13] evaluated the normal occipitocervical angle in healthy individuals using the McRae and Barnum [10] line, therefore, obtain 44°in lordosis.…”

Section: Methodsmentioning

confidence: 99%

Relevance of the cranioaxial angle in the occipitocervical stabilization using an original construct: a retrospective study on 50 patients

2009

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We present a retrospective study on a series composed of 50 patients, treated between 1992 and 2006, affected by pathologies of the craniocervical junction. All the patients were treated using an innovative procedure based on a cranial claw made up of low profile hooks, conceived by one of the authors. Advantages of this technique are, to our point of view, a higher resistance to cranial hooks dislodgment, when compared with screw fixation instrumentation, especially in pathological conditions, such as rheumatoid arthritis that leads to a qualitative deterioration of the bone stock and to the reduction of the occipital wall thickness. Occipitoaxial alignment was assessed radiographically using the McGregor line. We observed an improvement in the subjective evaluation of pain in all treated patients with a 46% improvement from the initial values. Moreover, patient stabilized with an occipitoaxial angle included in the physiological range showed better results either for the survival of the instrumentation or the onset of junctional pathology. Patients have been followed up afterwards and evaluated by the visual analogue scale for the assessment of pain and by the Nurick scale for the cases associated with myelopathy. We believe that cranial anchorage with a hook claw allows for an instrumentation provided with high stability, particularly useful in revision surgery and major instabilities. The study of the occipitoaxial angles showed that the better results and the long-lasting stability of the implant are correlated to a fusion angle included in the physiological range.

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“…1A-C). [11][12][13] For example, the angle between the McGregor line and the inferior surface of the axis should be within the range of 0-30 degrees, taking into consideration the long-term mechanical effects. 10) The angles between the inferior endplate of the C2 vertebra and the occiput line were measured using the Chamberlain, McRae, and McGregor lines on the lateral radiographs of 30 healthy volunteers.…”

Section: Discussionmentioning

confidence: 99%

“…[1][2][3][4][5]7,14) Various methods are available to measure the angle of the craniovertebral junction based on lateral radiography. [11][12][13] Here we describe a simple and reliable measurement of fixation angle during occipitocervical fusion.…”

Section: Introductionmentioning

confidence: 99%

Importance of Fixation Angle in Posterior Instrumented Occipitocervical Fusion -Technical Note-

Takami

Ichinose

Ishibashi

et al. 2008

Neurol. Med. Chir.(Tokyo)

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Occipitocervical fusion with the head in a functionally neutral position is critically important. Various methods have been proposed for measuring the angle of the craniovertebral junction based on lateral radiography. We describe a simple and reliable measurement of fixation angle during occipitocervical fusion using the line parallel to the bony palate and the posterior longitudinal line of the C2 vertebra. The normal range of the angle of the craniovertebral junction was measured in 30 normal healthy volunteers, 15 males and 15 females aged from 17 to 77 years (mean 45.1 years), without symptoms of neck pain or limitations of neck movement. The angle ranged from 85 to 118 degrees. The mean angle was 97.1 degrees in males and 102.6 degrees in females, with overall mean ± standard deviation of 99.9 ± 8.1 degrees. Careful adjustment of the angle of the craniovertebral junction can help to avoid postoperative complications such as dysphagia, dyspnea, and subaxial subluxation.

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Measurement of Occipitocervical Angle

Abstract: The McGregor line is the most reproducible and reliable method for measurement of the occipitocervical angle.

Cited by 34 publications

References 22 publications

The O-C2 angle established at occipito-cervical fusion dictates the patient’s destiny in terms of postoperative dyspnea and/or dysphagia

The O-C2 angle established at occipito-cervical fusion dictates the patient’s destiny in terms of postoperative dyspnea and/or dysphagia

Relevance of the cranioaxial angle in the occipitocervical stabilization using an original construct: a retrospective study on 50 patients

Importance of Fixation Angle in Posterior Instrumented Occipitocervical Fusion -Technical Note-

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