Radiological and surgical anatomy of ventral c1-c2 complex

Abstract

ventral plating. Although the TO approach to the CVJ is an effective and important approach, it is associated with a high rate of morbidity. Therefore, many surgeons have recently started to perform minimally-invasive transnasal (TN) endoscopic odontoidectomy. Both TO and TN approaches require information about bony and neurovascular structures. The aim of this study is to measure bony structures related to these approaches after anterior exploration of the C1 (first cervical vertebra)-C2 (second cervical vertebra) complex. █ INTRODUCTIONT he transoral (TO) approach is an important route to reach to the upper cervical spine. This approach is commonly used for decompression of the craniovertebral junction (CVJ) ventrally, particularly for decompression of the upper cervical spinal cord due to cranial settling of the odontoid, CVJ tumours and infections. This route has also been used occasionally for C0-C1-C2 (occipito-atlanto-axial complex) AIM: To evaluate anatomical data of the bony structures during exploration of the C1-C2 complex. MATERIAL and METHODS:This study included six formalin-fixed cadaveric head and neck specimens. Radiological images and anatomical measurements included: C1-C2 distance, bony distance between C1 anterior tubercle-nares and superior incisors, height of C1 anterior arch, and height and width of odontoid articular surface. RESULTS:The mean distance between C1 anterior tubercle-nares and superior incisors on maxilla were 96.16 ± 8.07 mm and 84.14 ± 9.16 mm, respectively. The mean height of C1 anterior arch was 13.89 mm. The meandistance between medial borders of right-left C1 lateral masses was 19.10 ± 1.80 mm. The mean distance between medial border of lateral midline on mass right and left sides were 9.43 ± 0.88 mm and 9.68 ± 0.97 mm, respectively. The mean height of C1 anterior arch at midline was 13.89 ± 2.48 mm, and the mean distance between ventral surface of anterior arch and ventral joint of odontoid at midline was 6.43 ± 1.29 mm. The anteroposterior, horizontal diameters of odontoid on its base were 12.12 ± 0.38 mm, and 11.12 ± 0.94 mm, respectively. The angles of transoral and transnasal approaches to C1 were 32.67 ± 4.59° and 32.00 ± 2.10°, respectively. CONCLUSION:A safe transoral or transnasal odontoidectomy requires accurate measurements and imaging regarding ventral C1-C2 relationships, distances of odontoid, lateral mass and midline.

Treatment of Upper Cervical Spinal Cord Injury (Unstable C1-C2) by Direct Visualization and Nailing Technique and the Advantages of Early MRI

“…Moreover, 3D preoperative planning can help understand the exact anatomy of C1 and C2 in each patient, reducing the risk of vertebral artery injury, as well as measuring the C2 isthmus height and width; understanding the detail of the morphological isthmus features can decrease the risk of vertebral artery injury and make the surgeon aware in some cases. C1 cover parts of the odontoid process [ 15 ], so it is essential to identify the exact problem in upper SCI and the presence of other abnormalities (bone fragments and degree of displacement). The complexity of C1 and C2 structure reveals that surgical procedure is a better choice that improves the stability of the C1-C2 combination.…”