Demonstration of craniocervical junction abnormalities for diagnosis of atlanto-occipital assimilation using MRI

Year 2018, Volume: 12 Issue: 2, 76 - 82, 15.08.2018

Ali Koç , Özgür Karabıyık , Turgut Tursem Tokmak , Aysel Özaşlamacı Mustafa Özdemir Gamze Türk

Abstract

Objectives: Atlanto-occipital assimilation (AOA) is one of the most common skeletal anomalies of the craniovertebral junction

(CVJ). Because its clinical symptomatology is non-specific and it has several variations, many cases go unnoticed which

may lead to additional and unnecessary radiological examinations. In this study, we aimed to present CVJ abnormalities with

MRI to improve diagnostic accuracy of AOA.

Methods: Cervical MRIs of the patients registered in PACS between January 2008 and October 2011 were scanned and AOA

was detected in 40 cases. Sagittal FSE T1 and T2-weighted cervical MRIs and axial T2*-GRE sequence images were re-evaluated

for AOA typing, anterior atlantodental interval (AADI), posterior atlantodental interval (PADI) measurements, spine fusion anomalies,

basilar invagination, tonsillar herniation, myelomalacia, suboccipital muscles and vertebral arteries (VAs).

Results: CVJ abnormalities were present in all cases and the most frequent association was observed in suboccipital muscles

(100%) and VAs (95%). 60% of the cases had decreased PADI, 32% C2–3 vertebrae fusion, 25% increased AADI, 22.5% basilar

invagination, 15% myelomalacia and 5% tonsillar herniation.

Conclusion: Suboccipital muscle abnormality was found in all AOA cases whatever the severity and type of the bony fusion.

VA anomaly was observed as the second most common abnormality and accompanied preferably the cases with lateral body

involvement. Being aware of additional CVJ abnormalities in MRI examinations may reduce unnecessary radiological examinations

by increasing the AOA diagnosis rate.

Keywords

assimilation, craniocervical, magnetic resonance imaging

References

• 1. Jadhav SD, Ambali MP, Patil RJ, Doshi MA, Roy PP. Assimillation of atlas in Indian dry skulls. JKIMSU 2012; 1:102-106.
• 2. Mudaliar RP, Shailaja S, Komala N. An osteological study of occipito cervical synostosis: its embryological and clinical significance. J Clin Diagn Res 2013; 7: 1835.
• 3. Pooja, J, Khursheed, R, Chiman, K, Manisha, H, Sb R. Cranio-vertebral junction anomaly: atlanto-occipital assimilation. Clin Ter 2015; 167:77-79.
• 4. Skrzat J, Mróz I, Jaworek JK, Walocha J. A case of occipitalization in the human skull. FoliaMorphol 2010; 69:134-137.
• 5. Menezes AH. Primary cranio-vertebral anomalies and the hindbrain herniation syndrome (Chiari I): database analysis. Pediatr Neurosurg 1995; 25:260-269.
• 6. Erbengi A, HK Öge. Congenital malformations of the craniovertebral junction: classification and surgical treatment. Acta Neurochir 1994; 27:180-185.
• 7. McRae DL, AS Barnum. Occipitalization of the atlas. Am J Roentgenol Radium Ther Nucl Med 1953; 70:23.
• 8. Bodon G, Tibor G, Claes O. Anatomical changes in occipitalization: is there an increased risk during the standard posterior approach? Eur Spine J 2013; 22:512-516.
• 9. Greenbery AD. Atlanto–axial Dislocation. Brain 1968; 91:655.
• 10. Hinck VC, Hopkins CE. Measurement of the atlanto-dental interval in the adult. Am J Roentgenol Radium Ther Nucl Med 1960; 84:945-951.
• 11. Chamberlain WE. Basilar impression (platybasia): bizarre developmental anomaly of occipital bone and upper cervical spine with striking and misleading neurologic manifestations.Yale J Biol Med 1939; 11:487–496.
• 12. Barkovich AJ, Wippold FJ, Sherman JL, Citrin CM. Significance of cerebellar tonsillar position on MR. Am J Neuroradiol 1986; 7:795–99.
• 13. Clark, JG, Abdullah KG, Steinmetz MP, Mroz TE. Biomechanics of the Craniovertebral Junction. INTECH 2011
• 14. Smoker WRK, Geetika K. Imaging the craniocervical junction. Child's Nervous System 2008; 24:1123-1145.
• 15. Hussain SS, Mavishetter, GF, Thomas ST, Prasanna LC, Muralidhar P. Occipitalization of Atlas: A case report. J Biomed Sci Res 2010; 2:73-5.
• 16. Wackenheim A. Roentgen diagnosis of the craniovertebral region. New York, Springer-Verlag 1974; 9-10.
• 17. Gholve, PA, Hosalkar, HS, Ricchetti, ET, Pollock, AN, Dormans, JP, Drummond, DS. Occipitalization of the atlas in children. J Bone Joint Surg Am. 2007; 89:571-578.
• 18. Zong R, Yin Y, Qiao G, Jin, Y, Yu X. Quantitative Measurements of the Skull Base and Craniovertebral Junction in Congenital Occipitalization of the Atlas: A Computed Tomography–Based Anatomic Study. World Neurosurg 2017; 99:96-103.
• 19. Vakili ST, Aguilar JC, Muller J. Sudden unexpected death associated with atlanto-occipitalfusion. Am J Forensic Medand Path 1985; 6:39–43.
• 20. Bundschuh C, Modic MT, Kearney F, Morris R, Deal C. Rheumatoid arthritis of the cervicalspine: surface-coil MR imaging. Am J Roentgenol 1988; 151:181-187.
• 21. Boden SD, Dodge LD, Bohlman HH, Rechtine GR. Rheumatoid arthritis of the cervicalspine. A long-term analysis with predictors of paralysis and recovery. J Bone Joint Surg Am 1993; 75:1282-1297.
• 22. Wang S, Wang C, Liu Y, Yan M, Zhou H. Anomalous vertebral artery in craniovertebral junction with occipitalization of the atlas. Spine 2009; 34:2838-2842.
• 23. Tubbs RS, Salter EG, Oakes WJ. The intracranial entrance of the atlantal segment of the vertebral artery in crania with occipitalization of the atlas. J Neurosurg 2006; 4:319-322.
• 24. Kassim NM, Latiff AA, Das S, et al. Atlanto-occipital fusion: an osteological study with clinical implications. Bratislavskelekarske listy 2009; 10:562-565.
• 25. Hallgren RC, Greenman PE, Rechtien JJ. Atrophy of suboccipital muscles in patients with chronic pain: a pilot study. J Am Osteopath Assoc 1994; 94:1032-1038.