J Neurosurg 47:115-118, 1977
An unusual atlanto-axial dislocation Case report
JOHN L. FOX, M . D . , AND ALVARO JEREZ, M . D .
Division of Neurosurgery, West Virginia University Medical Center, Morgantown, West Virginia, and Clinica Tiscapa, Managua, Nicaragua is A case is presented in which the patient sustained a complete dislocation of the odontoid process in front of the anterior arch of the first cervical vertebra. There was no fracture of the arch of C-1 vertebra. The patient was treated successfully by transoral excision of the odontoid process and the anterior arch of C-1. Twenty days later the patient's spine was stabilized posteriorly at C-I through C-3 with wire and methylmethacrylate. KEY WORDS cervical fusion
9
spinal dislocation
HE following case, as far as we can determine, represents a unique type of dislocation of the C-1 and C-2 vertebrae.
T
Case Report This 65-year-old physician was driving his automobile on June 14, 1975, in Managua, Nicaragua, when he was struck broadside from his right by another car. The patient was rendered immediately quadriplegic and was admitted to the local hospital. He did not recall the details of the accident. He was placed in traction using skull tongs. Examination. Five hours after the injury the neurological examination was normal. X-ray films of the cervical spine revealed the following a b n o r m a l i t i e s t h a t were subsequently confirmed at surgery (Fig. 1). Although no fractures were present, the odontoid process lay in front of the anterior arch of C-I (or, one can say the C-1 vertebra and
J. Neurosurg. / Volume 47 / July, 1977
9 transoral surgery
9
the c r a n i u m were dislocated posteriorly with relative inferior tilting of the C-1 posterior arch). The odontoid also was 1.5 c m to the right of the C-1 midline. The C-2 v e r t e b r a did not a p p e a r to be rotated on its axis since the spinous process and odontoid were in the same parasagittal plane on the anteroposterior view (Fig. 1 right). H o w e v e r , the C - 1 / C - 2 facet articulation was completely disrupted bilaterally, with the C-2 superior facets m o v e d about 1.5 cm to the right of the C-1 inferior facets. The right C-2 superior facet (Fig. 1 lower right) was a b o v e and anterior to the right C-1 inferior facet. The left C-2 superior facet was anterior to the left C-1 inferior facet. Operation. On June 18, 1975, the axis and atlas were exposed surgically via an anterior transoral approach. The odontoid previously could be palpated through the open mouth. The axis-atlas relationship was as described above, except that the odontoid a p p e a r e d to 115
J. L. F o x a n d A. J e r e z
FIG. I. Cervical spine films (upper), and artist's drawings (lower). Left: Lateral view, showing the odontoid process in front of the anterior arch of C-I (arrow). Right: Open-mouth anteroposterior view, showing the odontoid process (arrow). a: odontoid process in front of anterior arch of C-l; b: right superior facet of C-2; c: left superior facet of C-2; d: right inferior facet of C-1; e: left inferior facet of C-1; f: spinous process of C-2; g: mastoid process; h: superior facet of C-3.
be at the midline (rather than to the right), and the anterior arch of the atlas seemed to be displaced leftward. The exposed odontoid process was removed easily, but attempts to relocate the normal axis-atlas alignment in order to fuse the facet joints failed. Therefore, the anterior arch of the atlas was excised to allow decompression of the spinal cord. Postoperative Course. Postoperatively the wound healed well. Twenty days later the patient underwent an uneventful wiring and methylmethacrylate stabilization. The spinous processes and laminae of C-l, C-2, and C-3 were immobilized by a posterior approach (Fig. 2). Since then he has been able to walk, and has resumed his normal activities. ] 16
Discussion Our review of the literature has not turned up any similar case of anterior dislocation of the odontoid process without fracture. The patient's transient quadriplegia was most likely due to either compression of the spinal cord by the odontoid process as it ruptured its ligaments during an initial flexion of C-1 and extension of C-2, or the subsequent encroachment o f the anterior arch of C-I on the spinal cord. Transient stretching, spasm, a n d / o r occlusion of the vertebral arteries and its branches may have also played a role. Vertebral angiography was not done in this case. A review of anatomical and biomechanical descriptions of the axis and atlas indicated the
J. Neurosurg. / Volume 47 / July. 1977
Atlanto-axial dislocation
FIG. 2. Postoperative films. There is no change in the fixed original C-1 and C-2 relationships. The odontoid process of C-2 and anterior arch of C-I are removed. The stabilizing wires (encased in methylmethacrylate) can be seen.
following ligaments must have been ruptured to allow this dislocation: 1,8,7 the alar ligaments (including the apical odontoid and lateral check ligaments to the occiput), the anterior atlanto-axial ligament (anterior longitudinal ligament), and the articular capsules of both facet joints. The transverse ligament m u s t have been severely damaged, although not necessarily ruptured. In view of such instability we had hoped to remove the odontoid process, relocate the axis against the atlas, and fuse the C - 1 / C - 2 facet joints via the transoral approach. Since we were unable to relocate the atlas, we elected to remove the posteriorly dislocated anterior arch of C-1. This technique of approach to the C - 1 / C - 2 region for decompression with or without fusion now is well d o c u m e n t e d ) -5,7-13 One of the largest series done for atlanto-axial dislocation is that of Toczek, TM who now has 11 cases o f transoral decompression and fusion (two were fused posteriorly after anterior decompression). The similar decompression in our case allowed for greater safety during the subsequent posterior cervical stabilization. J. Neurosurg. / Volume 47 / July, 1977
References 1. Bailey RW: The Cervical Spine. Philadelphia: Lea and Febiger, 1974, pp 10-46 2. Bonney G: Stabilization of the upper cervical spine by the transpharyngeal route. Proc R Soc Med 63:896-897, 1970 3. Estridge MN, Smith RA: Transoral fusion of odontoid fracture. Case report. J Neurosurg 27:462-465, 1967 4. Fang HSY, Ong GB: Direct anterior approach to the upper cervical spine. J Bone Joint Surg 44A:1588-1604, 1962 5. Fang HSY, Ong GB, Hodgson AR: Anterior spinal fusion. The operative approaches. Clin Orthop 35:16-33, 1964 6. Goss CM (ed): Gray's Anatomy of the Human Body, ed 26. Philadelphia: Lea and Febiger, 1954, pp 331-336 7. Greenberg AD: Atlanto-axial dislocations. Brain 91:655-684, 1968 8. Greenberg AD, Scoville WB, Davey LM: Transoral decompression of atlanto-axial dislocation due to odontoid hypoplasia. Report of two cases. J Neurosurg 28:266-269, 1968 9. de Rougemont J, Abada M, Barge M: Les possibilit6s de la voie d'abord ant6rieure dans les ]|7
J, L. Fox and A. Jerez 16sions des trois premi6res vert6bres cervicales. Neurochirurgie 12:323-336, 1966 10. Sukoff MH, Kadin MM, Moran T: Transoral decompression for myelopathy caused by rheumatoid arthritis of the cervical spine. Case report. J Neurosurg 37:493-497, 1972 11. Thompson H: Transpharyngeal fusion of the upper cervical spine. Proe R Soc Med 63:893-896, 1970 12. Toczek SK: Personal communication, 1975
] ]8
13. Verbiest H: Anterolateral operations for fractures or dislocations of the cervical spine due to injuries or previous surgical interventions. Clin Neurosurg 20:334-366, 1973 Address reprint requests to: John L. Fox, M.D., Division of Neurosurgery, West Virginia University Medical Center, Morgantown, West Virginia 26506.
J. Neurosurg. / Volume 47 / July, 1977
An unusual atlanto-axial dislocation Case report
JOHN L. FOX, M . D . , AND ALVARO JEREZ, M . D .
Division of Neurosurgery, West Virginia University Medical Center, Morgantown, West Virginia, and Clinica Tiscapa, Managua, Nicaragua is A case is presented in which the patient sustained a complete dislocation of the odontoid process in front of the anterior arch of the first cervical vertebra. There was no fracture of the arch of C-1 vertebra. The patient was treated successfully by transoral excision of the odontoid process and the anterior arch of C-1. Twenty days later the patient's spine was stabilized posteriorly at C-I through C-3 with wire and methylmethacrylate. KEY WORDS cervical fusion
9
spinal dislocation
HE following case, as far as we can determine, represents a unique type of dislocation of the C-1 and C-2 vertebrae.
T
Case Report This 65-year-old physician was driving his automobile on June 14, 1975, in Managua, Nicaragua, when he was struck broadside from his right by another car. The patient was rendered immediately quadriplegic and was admitted to the local hospital. He did not recall the details of the accident. He was placed in traction using skull tongs. Examination. Five hours after the injury the neurological examination was normal. X-ray films of the cervical spine revealed the following a b n o r m a l i t i e s t h a t were subsequently confirmed at surgery (Fig. 1). Although no fractures were present, the odontoid process lay in front of the anterior arch of C-I (or, one can say the C-1 vertebra and
J. Neurosurg. / Volume 47 / July, 1977
9 transoral surgery
9
the c r a n i u m were dislocated posteriorly with relative inferior tilting of the C-1 posterior arch). The odontoid also was 1.5 c m to the right of the C-1 midline. The C-2 v e r t e b r a did not a p p e a r to be rotated on its axis since the spinous process and odontoid were in the same parasagittal plane on the anteroposterior view (Fig. 1 right). H o w e v e r , the C - 1 / C - 2 facet articulation was completely disrupted bilaterally, with the C-2 superior facets m o v e d about 1.5 cm to the right of the C-1 inferior facets. The right C-2 superior facet (Fig. 1 lower right) was a b o v e and anterior to the right C-1 inferior facet. The left C-2 superior facet was anterior to the left C-1 inferior facet. Operation. On June 18, 1975, the axis and atlas were exposed surgically via an anterior transoral approach. The odontoid previously could be palpated through the open mouth. The axis-atlas relationship was as described above, except that the odontoid a p p e a r e d to 115
J. L. F o x a n d A. J e r e z
FIG. I. Cervical spine films (upper), and artist's drawings (lower). Left: Lateral view, showing the odontoid process in front of the anterior arch of C-I (arrow). Right: Open-mouth anteroposterior view, showing the odontoid process (arrow). a: odontoid process in front of anterior arch of C-l; b: right superior facet of C-2; c: left superior facet of C-2; d: right inferior facet of C-1; e: left inferior facet of C-1; f: spinous process of C-2; g: mastoid process; h: superior facet of C-3.
be at the midline (rather than to the right), and the anterior arch of the atlas seemed to be displaced leftward. The exposed odontoid process was removed easily, but attempts to relocate the normal axis-atlas alignment in order to fuse the facet joints failed. Therefore, the anterior arch of the atlas was excised to allow decompression of the spinal cord. Postoperative Course. Postoperatively the wound healed well. Twenty days later the patient underwent an uneventful wiring and methylmethacrylate stabilization. The spinous processes and laminae of C-l, C-2, and C-3 were immobilized by a posterior approach (Fig. 2). Since then he has been able to walk, and has resumed his normal activities. ] 16
Discussion Our review of the literature has not turned up any similar case of anterior dislocation of the odontoid process without fracture. The patient's transient quadriplegia was most likely due to either compression of the spinal cord by the odontoid process as it ruptured its ligaments during an initial flexion of C-1 and extension of C-2, or the subsequent encroachment o f the anterior arch of C-I on the spinal cord. Transient stretching, spasm, a n d / o r occlusion of the vertebral arteries and its branches may have also played a role. Vertebral angiography was not done in this case. A review of anatomical and biomechanical descriptions of the axis and atlas indicated the
J. Neurosurg. / Volume 47 / July. 1977
Atlanto-axial dislocation
FIG. 2. Postoperative films. There is no change in the fixed original C-1 and C-2 relationships. The odontoid process of C-2 and anterior arch of C-I are removed. The stabilizing wires (encased in methylmethacrylate) can be seen.
following ligaments must have been ruptured to allow this dislocation: 1,8,7 the alar ligaments (including the apical odontoid and lateral check ligaments to the occiput), the anterior atlanto-axial ligament (anterior longitudinal ligament), and the articular capsules of both facet joints. The transverse ligament m u s t have been severely damaged, although not necessarily ruptured. In view of such instability we had hoped to remove the odontoid process, relocate the axis against the atlas, and fuse the C - 1 / C - 2 facet joints via the transoral approach. Since we were unable to relocate the atlas, we elected to remove the posteriorly dislocated anterior arch of C-1. This technique of approach to the C - 1 / C - 2 region for decompression with or without fusion now is well d o c u m e n t e d ) -5,7-13 One of the largest series done for atlanto-axial dislocation is that of Toczek, TM who now has 11 cases o f transoral decompression and fusion (two were fused posteriorly after anterior decompression). The similar decompression in our case allowed for greater safety during the subsequent posterior cervical stabilization. J. Neurosurg. / Volume 47 / July, 1977
References 1. Bailey RW: The Cervical Spine. Philadelphia: Lea and Febiger, 1974, pp 10-46 2. Bonney G: Stabilization of the upper cervical spine by the transpharyngeal route. Proc R Soc Med 63:896-897, 1970 3. Estridge MN, Smith RA: Transoral fusion of odontoid fracture. Case report. J Neurosurg 27:462-465, 1967 4. Fang HSY, Ong GB: Direct anterior approach to the upper cervical spine. J Bone Joint Surg 44A:1588-1604, 1962 5. Fang HSY, Ong GB, Hodgson AR: Anterior spinal fusion. The operative approaches. Clin Orthop 35:16-33, 1964 6. Goss CM (ed): Gray's Anatomy of the Human Body, ed 26. Philadelphia: Lea and Febiger, 1954, pp 331-336 7. Greenberg AD: Atlanto-axial dislocations. Brain 91:655-684, 1968 8. Greenberg AD, Scoville WB, Davey LM: Transoral decompression of atlanto-axial dislocation due to odontoid hypoplasia. Report of two cases. J Neurosurg 28:266-269, 1968 9. de Rougemont J, Abada M, Barge M: Les possibilit6s de la voie d'abord ant6rieure dans les ]|7
J, L. Fox and A. Jerez 16sions des trois premi6res vert6bres cervicales. Neurochirurgie 12:323-336, 1966 10. Sukoff MH, Kadin MM, Moran T: Transoral decompression for myelopathy caused by rheumatoid arthritis of the cervical spine. Case report. J Neurosurg 37:493-497, 1972 11. Thompson H: Transpharyngeal fusion of the upper cervical spine. Proe R Soc Med 63:893-896, 1970 12. Toczek SK: Personal communication, 1975
] ]8
13. Verbiest H: Anterolateral operations for fractures or dislocations of the cervical spine due to injuries or previous surgical interventions. Clin Neurosurg 20:334-366, 1973 Address reprint requests to: John L. Fox, M.D., Division of Neurosurgery, West Virginia University Medical Center, Morgantown, West Virginia 26506.
J. Neurosurg. / Volume 47 / July, 1977
