HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Leone, A. Articles by Marano, P. Search for Related Content PubMed PubMed Citation Articles by Leone, A. Articles by Marano, P.

Occipital Condylar Fractures: A Review¹

¹ From the Departments of Radiology (A.L., A.C., C.C, L.L., P.M.) and Neurosurgery (A.P.), Università Cattolica del Sacro Cuore, Policlinico "Agostino Gemelli," Largo Agostino Gemelli, 8, 00168 Rome, Italy. Received January 12, 1999; revision requested March 5; final revision received September 13; accepted September 14. Address correspondence to A.L. (e-mail: a.leonemd@tiscalinet.it).

View larger version (20K): [in a new window]   Figure 1. Schematics show the anatomy of the CCJ. A, Midsagittal view. B, Posterior view of coronal section passing through the occipital condyles and posterior arches of the atlas and axis after dissection of the dura mater, posterior longitudinal ligament, and tectorial membrane. C, Transverse view from above of the median atlanto-odontoid joints after dissection of the occiput, dura mater, posterior longitudinal ligament, tectorial membrane, and anterior and posterior occipitoatloid membrane. abCL = ascending band of the cruciform ligament, AL = alar ligaments (atlantal and occipital portions), AOAM = anterior occipitoatloid membrane, AOL = atlanto-odontoid ligament, ApL = apical ligament, dbCL = descending band of the cruciform ligament, DM = dura mater, OC = occipital condyle, PLL = posterior longitudinal ligament, POAM = posterior occipitoatloid membrane, SAFA = superior articular facet of the atlas, TGVA = transverse groove of the atlas for vertebral artery, TL = transverse ligament of the atlas, TM = tectorial membrane.

View larger version (27K): [in a new window]   Figure 2. Schematics show the anatomic relationships of the occipital condyles with the surrounding neurovascular structures. A, Posterior view of a coronal section passing through the occipital bone and the posterior arches of the atlas and axis. B, Posterior view of a coronal section passing through the occipital condyles and the posterior arches of the atlas and axis anterior to the section in A after dissection of the spinal cord, vertebral artery, dura mater, posterior longitudinal ligament, and tectorial membrane. C, Three-quarter view of sphenoid, temporal, and occipital (anterior and lateral portions) bones. BA = basilar artery, HC = hypoglossal canal, JF = jugular foramen, JT = jugular tubercle, OB = occipital bone, OC = occipital condyle, SC = spinal cord, SS = sigmoid sinus, VA = vertebral artery, VP = venous plexus surrounding the vertebral artery. (Modified and reprinted, with permission, from reference 53.)

View larger version (19K): [in a new window]   Figure 3. Schematics show the types of OCF according to the classification system of Anderson and Montesano (8). a, Coronal and b, transverse views from below show a type I OCF, which is a comminuted fracture of the occipital condyle (black arrows) with minimal or no fragment displacement into the foramen magnum. c, Coronal and d, transverse views from below show a type II OCF, which is a basilar skull fracture (arrowheads) extending into the occipital condyle. e, Coronal and f, transverse views from below show a type III OCF, which is a fracture with a fragment displaced medially from the inferomedial aspect of the occipital condyle (white arrows) into the foramen magnum.

View larger version (119K): [in a new window]   Figure 4a. Type I OCF in a 39-year-old woman involved in a motor vehicle accident as a driver. Glasgow Coma Scale score at admission was 13, without lower cranial nerve palsy. (a) Transverse and (b) direct coronal CT scans demonstrate an impaction fracture of the inferomedial aspect of the right occipital condyle (arrow) with minimal fragment displacement. Associated injuries included facial fractures (not shown). The patient was treated with a soft cervical collar.

View larger version (151K): [in a new window]   Figure 4b. Type I OCF in a 39-year-old woman involved in a motor vehicle accident as a driver. Glasgow Coma Scale score at admission was 13, without lower cranial nerve palsy. (a) Transverse and (b) direct coronal CT scans demonstrate an impaction fracture of the inferomedial aspect of the right occipital condyle (arrow) with minimal fragment displacement. Associated injuries included facial fractures (not shown). The patient was treated with a soft cervical collar.

View larger version (120K): [in a new window]   Figure 5a. Type II OCF in an 18-year-old man involved in a motor vehicle accident as a pedestrian. Glasgow Coma Scale score at admission was 8, without lower cranial nerve palsy. (a) Transverse CT scan shows a linear fracture of the left occipital condyle (arrowhead), which is an extension of a comminuted skull base fracture (arrow). (b) Transverse CT scan demonstrates a bone fragment (arrow) medial to the left jugular foramen. (c) Two-dimensional oblique sagittal reformation CT image clearly demonstrates the craniocaudal extent of the fracture line (arrow), which involves the osseous ring of the hypoglossal canal. Associated injuries included cortical contusions and a wedge fracture of C6 (not shown). The patient was treated with a halo vest.

View larger version (124K): [in a new window]   Figure 5b. Type II OCF in an 18-year-old man involved in a motor vehicle accident as a pedestrian. Glasgow Coma Scale score at admission was 8, without lower cranial nerve palsy. (a) Transverse CT scan shows a linear fracture of the left occipital condyle (arrowhead), which is an extension of a comminuted skull base fracture (arrow). (b) Transverse CT scan demonstrates a bone fragment (arrow) medial to the left jugular foramen. (c) Two-dimensional oblique sagittal reformation CT image clearly demonstrates the craniocaudal extent of the fracture line (arrow), which involves the osseous ring of the hypoglossal canal. Associated injuries included cortical contusions and a wedge fracture of C6 (not shown). The patient was treated with a halo vest.

View larger version (75K): [in a new window]   Figure 5c. Type II OCF in an 18-year-old man involved in a motor vehicle accident as a pedestrian. Glasgow Coma Scale score at admission was 8, without lower cranial nerve palsy. (a) Transverse CT scan shows a linear fracture of the left occipital condyle (arrowhead), which is an extension of a comminuted skull base fracture (arrow). (b) Transverse CT scan demonstrates a bone fragment (arrow) medial to the left jugular foramen. (c) Two-dimensional oblique sagittal reformation CT image clearly demonstrates the craniocaudal extent of the fracture line (arrow), which involves the osseous ring of the hypoglossal canal. Associated injuries included cortical contusions and a wedge fracture of C6 (not shown). The patient was treated with a halo vest.

View larger version (111K): [in a new window]   Figure 6a. Type II OCF in a 17-year-old girl involved in a motor vehicle accident as a passenger. Glasgow Coma Scale score at admission was 5, without lower cranial nerve palsy. (a, b) Transverse CT scans (1-mm collimation) (a) through the occipital condyles and (b) 6 mm cranial to a show an extensive comminuted right skull base fracture (arrowhead in a) extending into the ipsilateral occipital condyle (arrows in a) and involving the osseous ring of the ipsilateral jugular foramen (open arrows in b), with evidence of a distorted fragment (solid arrow in b). (c) Two transverse CT images through C1 and C2 vertebrae are superimposed to demonstrate associated mild atlantoaxial rotatory subluxation. Associated injuries included right petrous temporal bone fractures and pneumocephalus (not shown). The patient was treated with a Philadelphia cervical collar.

View larger version (106K): [in a new window]   Figure 6b. Type II OCF in a 17-year-old girl involved in a motor vehicle accident as a passenger. Glasgow Coma Scale score at admission was 5, without lower cranial nerve palsy. (a, b) Transverse CT scans (1-mm collimation) (a) through the occipital condyles and (b) 6 mm cranial to a show an extensive comminuted right skull base fracture (arrowhead in a) extending into the ipsilateral occipital condyle (arrows in a) and involving the osseous ring of the ipsilateral jugular foramen (open arrows in b), with evidence of a distorted fragment (solid arrow in b). (c) Two transverse CT images through C1 and C2 vertebrae are superimposed to demonstrate associated mild atlantoaxial rotatory subluxation. Associated injuries included right petrous temporal bone fractures and pneumocephalus (not shown). The patient was treated with a Philadelphia cervical collar.

View larger version (99K): [in a new window]   Figure 6c. Type II OCF in a 17-year-old girl involved in a motor vehicle accident as a passenger. Glasgow Coma Scale score at admission was 5, without lower cranial nerve palsy. (a, b) Transverse CT scans (1-mm collimation) (a) through the occipital condyles and (b) 6 mm cranial to a show an extensive comminuted right skull base fracture (arrowhead in a) extending into the ipsilateral occipital condyle (arrows in a) and involving the osseous ring of the ipsilateral jugular foramen (open arrows in b), with evidence of a distorted fragment (solid arrow in b). (c) Two transverse CT images through C1 and C2 vertebrae are superimposed to demonstrate associated mild atlantoaxial rotatory subluxation. Associated injuries included right petrous temporal bone fractures and pneumocephalus (not shown). The patient was treated with a Philadelphia cervical collar.

View larger version (124K): [in a new window]   Figure 7a. Type II OCF in a 23-year-old woman who fell from a horse. Glasgow Coma Scale score at admission was 10, without lower cranial nerve palsy. These (a) 5-mm and (b) 1-mm collimation transverse CT scans clearly demonstrate a left basilar skull fracture (open arrow in a) extending ipsilaterally through the jugular foramen and into the occipital condyle (solid arrows). Associated injuries included right subdural hematoma and a wedge fracture of T12 (not shown). The patient was treated with a hard cervical collar.

View larger version (121K): [in a new window]   Figure 7b. Type II OCF in a 23-year-old woman who fell from a horse. Glasgow Coma Scale score at admission was 10, without lower cranial nerve palsy. These (a) 5-mm and (b) 1-mm collimation transverse CT scans clearly demonstrate a left basilar skull fracture (open arrow in a) extending ipsilaterally through the jugular foramen and into the occipital condyle (solid arrows). Associated injuries included right subdural hematoma and a wedge fracture of T12 (not shown). The patient was treated with a hard cervical collar.

View larger version (119K): [in a new window]   Figure 8a. Type III OCF in a 16-year-old boy involved in a motorcycle accident as a passenger. Glasgow Coma Scale score at admission was 8, without lower cranial nerve palsy. The patient had no associated intracranial lesions, spinal fractures, or systemic injuries. CT scans and MR images of the CCJ were obtained 2 weeks after trauma, after clinical and radiographic examinations proved stability of the cervical spine, and during treatment with hard cervical collar. (a) Transverse and (b) direct coronal CT scans show an avulsion fracture (arrow) of the inferomedial aspect of the right occipital condyle at the insertion site of the ipsilateral alar ligament, with substantial medial displacement of the bone fragment (compare with Fig 4 in which an impaction fracture resulted in only minimal displacement of the bone fragment). (c) Coronal T1-weighted MR image shows a subtle area of high signal intensity (arrowhead) in the soft tissues medial to the bone fragment (solid arrow), with retraction of the atlantal portion of the ipsilateral alar ligament. This area showed high signal intensity also on the T2*-weighted images (not shown) and was most likely due to edema, inflammation, and hemorrhage at the site of ligamentous injury. The open arrows indicate the normal atlantal portion of the left alar ligament.

View larger version (175K): [in a new window]   Figure 8b. Type III OCF in a 16-year-old boy involved in a motorcycle accident as a passenger. Glasgow Coma Scale score at admission was 8, without lower cranial nerve palsy. The patient had no associated intracranial lesions, spinal fractures, or systemic injuries. CT scans and MR images of the CCJ were obtained 2 weeks after trauma, after clinical and radiographic examinations proved stability of the cervical spine, and during treatment with hard cervical collar. (a) Transverse and (b) direct coronal CT scans show an avulsion fracture (arrow) of the inferomedial aspect of the right occipital condyle at the insertion site of the ipsilateral alar ligament, with substantial medial displacement of the bone fragment (compare with Fig 4 in which an impaction fracture resulted in only minimal displacement of the bone fragment). (c) Coronal T1-weighted MR image shows a subtle area of high signal intensity (arrowhead) in the soft tissues medial to the bone fragment (solid arrow), with retraction of the atlantal portion of the ipsilateral alar ligament. This area showed high signal intensity also on the T2*-weighted images (not shown) and was most likely due to edema, inflammation, and hemorrhage at the site of ligamentous injury. The open arrows indicate the normal atlantal portion of the left alar ligament.

View larger version (137K): [in a new window]   Figure 8c. Type III OCF in a 16-year-old boy involved in a motorcycle accident as a passenger. Glasgow Coma Scale score at admission was 8, without lower cranial nerve palsy. The patient had no associated intracranial lesions, spinal fractures, or systemic injuries. CT scans and MR images of the CCJ were obtained 2 weeks after trauma, after clinical and radiographic examinations proved stability of the cervical spine, and during treatment with hard cervical collar. (a) Transverse and (b) direct coronal CT scans show an avulsion fracture (arrow) of the inferomedial aspect of the right occipital condyle at the insertion site of the ipsilateral alar ligament, with substantial medial displacement of the bone fragment (compare with Fig 4 in which an impaction fracture resulted in only minimal displacement of the bone fragment). (c) Coronal T1-weighted MR image shows a subtle area of high signal intensity (arrowhead) in the soft tissues medial to the bone fragment (solid arrow), with retraction of the atlantal portion of the ipsilateral alar ligament. This area showed high signal intensity also on the T2*-weighted images (not shown) and was most likely due to edema, inflammation, and hemorrhage at the site of ligamentous injury. The open arrows indicate the normal atlantal portion of the left alar ligament.

View larger version (114K): [in a new window]   Figure 9a. Type III OCF in a 24-year-old woman involved in a motor vehicle accident as a passenger. Glasgow Coma Scale score at admission was 7, with cranial nerves IX and X palsy. Transverse CT scans (1-mm collimation) (a) through the occipital condyles and (b) 3 mm cranial to a show left OCF (arrows in a) with fragment displacement (arrowhead in b) into the foramen magnum. Associated injuries included lateral craniocervical subluxation (not shown). The patient was treated with occipitocervical fusion.

View larger version (115K): [in a new window]   Figure 9b. Type III OCF in a 24-year-old woman involved in a motor vehicle accident as a passenger. Glasgow Coma Scale score at admission was 7, with cranial nerves IX and X palsy. Transverse CT scans (1-mm collimation) (a) through the occipital condyles and (b) 3 mm cranial to a show left OCF (arrows in a) with fragment displacement (arrowhead in b) into the foramen magnum. Associated injuries included lateral craniocervical subluxation (not shown). The patient was treated with occipitocervical fusion.

View larger version (150K): [in a new window]   Figure 10a. Type III OCF in a 48-year-old man involved in a motor vehicle accident. He was admitted to another institution where CT scans suggested a fracture of the left occipital condyle with superomedial displacement of a bone fragment. The patient was treated with a hard cervical collar and, 3 months later, was transferred to our institution for further treatment. On admission, the patient was conscious and had a left Collet-Sicard syndrome and signs of cerebellar dysfunction. (a) Transverse CT scan and (b) surface rendered three-dimensional CT reformation from above demonstrate a healed left OCF with medial upward displacement of a bone fragment (asterisk). (c) Coronal T1-weighted MR image better depicts the displacement of the left occipital condylar fragment (black asterisk) in the posterior fossa, impinging on the medulla (arrowheads); a left cerebellar infarction is clearly seen (white asterisk). (d) Frontal reconstruction of a three-dimensional time-of-flight MR angiogram shows that the distal left vertebral artery is distinctly narrowed and displaced (small arrows) by the medial upward displacement of the left occipital condylar fragment. The source images (not shown) demonstrated the related cranial displacement and entrapment of the caudal loop of the left posteroinferior cerebellar artery and lack of evidence of the left anteroinferior cerebellar artery. Large arrow = right anteroinferior cerebellar artery.

View larger version (151K): [in a new window]   Figure 10b. Type III OCF in a 48-year-old man involved in a motor vehicle accident. He was admitted to another institution where CT scans suggested a fracture of the left occipital condyle with superomedial displacement of a bone fragment. The patient was treated with a hard cervical collar and, 3 months later, was transferred to our institution for further treatment. On admission, the patient was conscious and had a left Collet-Sicard syndrome and signs of cerebellar dysfunction. (a) Transverse CT scan and (b) surface rendered three-dimensional CT reformation from above demonstrate a healed left OCF with medial upward displacement of a bone fragment (asterisk). (c) Coronal T1-weighted MR image better depicts the displacement of the left occipital condylar fragment (black asterisk) in the posterior fossa, impinging on the medulla (arrowheads); a left cerebellar infarction is clearly seen (white asterisk). (d) Frontal reconstruction of a three-dimensional time-of-flight MR angiogram shows that the distal left vertebral artery is distinctly narrowed and displaced (small arrows) by the medial upward displacement of the left occipital condylar fragment. The source images (not shown) demonstrated the related cranial displacement and entrapment of the caudal loop of the left posteroinferior cerebellar artery and lack of evidence of the left anteroinferior cerebellar artery. Large arrow = right anteroinferior cerebellar artery.

View larger version (168K): [in a new window]   Figure 10c. Type III OCF in a 48-year-old man involved in a motor vehicle accident. He was admitted to another institution where CT scans suggested a fracture of the left occipital condyle with superomedial displacement of a bone fragment. The patient was treated with a hard cervical collar and, 3 months later, was transferred to our institution for further treatment. On admission, the patient was conscious and had a left Collet-Sicard syndrome and signs of cerebellar dysfunction. (a) Transverse CT scan and (b) surface rendered three-dimensional CT reformation from above demonstrate a healed left OCF with medial upward displacement of a bone fragment (asterisk). (c) Coronal T1-weighted MR image better depicts the displacement of the left occipital condylar fragment (black asterisk) in the posterior fossa, impinging on the medulla (arrowheads); a left cerebellar infarction is clearly seen (white asterisk). (d) Frontal reconstruction of a three-dimensional time-of-flight MR angiogram shows that the distal left vertebral artery is distinctly narrowed and displaced (small arrows) by the medial upward displacement of the left occipital condylar fragment. The source images (not shown) demonstrated the related cranial displacement and entrapment of the caudal loop of the left posteroinferior cerebellar artery and lack of evidence of the left anteroinferior cerebellar artery. Large arrow = right anteroinferior cerebellar artery.

View larger version (164K): [in a new window]   Figure 10d. Type III OCF in a 48-year-old man involved in a motor vehicle accident. He was admitted to another institution where CT scans suggested a fracture of the left occipital condyle with superomedial displacement of a bone fragment. The patient was treated with a hard cervical collar and, 3 months later, was transferred to our institution for further treatment. On admission, the patient was conscious and had a left Collet-Sicard syndrome and signs of cerebellar dysfunction. (a) Transverse CT scan and (b) surface rendered three-dimensional CT reformation from above demonstrate a healed left OCF with medial upward displacement of a bone fragment (asterisk). (c) Coronal T1-weighted MR image better depicts the displacement of the left occipital condylar fragment (black asterisk) in the posterior fossa, impinging on the medulla (arrowheads); a left cerebellar infarction is clearly seen (white asterisk). (d) Frontal reconstruction of a three-dimensional time-of-flight MR angiogram shows that the distal left vertebral artery is distinctly narrowed and displaced (small arrows) by the medial upward displacement of the left occipital condylar fragment. The source images (not shown) demonstrated the related cranial displacement and entrapment of the caudal loop of the left posteroinferior cerebellar artery and lack of evidence of the left anteroinferior cerebellar artery. Large arrow = right anteroinferior cerebellar artery.

View larger version (50K): [in a new window]   Figure 11. Imaging criteria for CCJ instability (5,35). On the basis of the results of radiography, CT, and/or MR imaging, CCJ is considered to be stable if none of the criteria are detected and unstable if a single criterion or a combination of them are detected (5).