• Journal of Korean Neurosurgical Society
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• v.29 no.4
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• pp.580-585
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• 2000

The atlantoaxial rotatory fixation is a uncommon disease of deformity, occuring much more frequently in children than in adults. Despite of its benign clinical course, delayed recognition or improper management may cause persistent deformity or recurrence. We report three cases of typical atlantoaxial rotatory fixation. Successful reduction was achieved with posterior atlantoaxial fusion in one case and nonoperative treatment in others. We emphasize that it is necessary to perform dynamic CT scan to obtain correct diagnosis and to plan proper treatment for this disease entity.

• Journal of Korean Neurosurgical Society
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• v.37 no.5
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• pp.380-382
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• 2005

We report a case of atlantoaxial subluxation with bilateral high-riding vertebral artery with narrow isthmus. Because of the potential risk of bilateral vertebral artery injury, we performed atlantoaxial fixation using rod and screw instead of transarticular screw fixation. Although postoperative computed tomography reconstruction demonstrated slight breach of bilateral vertebral artery groove, postoperative angiography showed no evidence of vertebral artery injury. Though technically demanding, atlantoaxial fixation using rod and screw can be a one of the treatment options for atlantoaxial instability with bilateral high riding vertebral artery.

• Journal of Korean Neurosurgical Society
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• v.41 no.4
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• pp.248-251
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• 2007

Atlantoaxial rotatory dislocation [AARD] is an uncommon disorder of childhood in which clinical diagnosis is generally difficult and often made late. It is very rare in adults because of the unique biomechanical features of the atlantoaxial articulation. We report a case of post-traumatic AARD in an adult. Reduction was difficult to obtain by skull traction and gentle manipulation. Therefore, the patient was treated surgically by an open reduction, transpedicular screw fixation, and posterior C1-2 wiring with graft. The normal atlantoaxial relation was restored with disappearance of torticollis. Postoperatively, the patient remains neurologically intact and has radiographic documentation of fusion. Atlantoaxial transpedicular screw fixation can be one of the treatment options for the AARD.

• Journal of Korean Neurosurgical Society
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• v.29 no.1
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• pp.95-100
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• 2000

Objective : Posterior transarticular screw fixation is known to be one of the best surgical method for the atlantoaxial instability. We assessed the complication and operative risk in 15 patients. Patients and Methods : Between January 1997 and April 1998, 15 patients suffering from this condition were admitted to our institution. Atlantoaxial instability was caused by C1 or C2 fractures in 11, rheumatoid arthritis in 2, and os odontoideum in 2. This technique was used in the treatment of 13 patients and 2 patients was used in sublaminar wire fixation only. Bilateral C1-C2 screws were placed in 11 patients ; 2 patients had only one screw placed becauce of an anomalous vertebral artery and axial destruction. Follow-up period ranged from 5 to 20 months. Results : Most screws were positioned satisfactorily. One screw was malpositioned. No patients had neurological complications. Conclusion : Rigidly fixating C1-C2 instability with transarticular screws showed a significantly higher fusion rate than that achieved using wired grafts alone. The risk of screw malpositioning and catastrophic vascular or neural injury is small and can be minimized by assessing the position of the transverse foramen on preoperative computed tomographic scans and by correctly using intraoperative fluoroscopy and surgeon's precaution.

• Journal of Korean Neurosurgical Society
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• v.52 no.1
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• pp.21-26
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• 2012

Objective : To evaluate a new posterior atlantoaxial fixation technique using a nitinol shape memory loop as a simple method that avoids the risk of vertebral artery or nerve injury. Methods : We retrospectively evaluated 14 patients with atlantoaxial instability who had undergone posterior C1-2 fusion using a nitinol shape memory loop. The success of fusion was determined clinically and radiologically. We reviewed patients' neurologic outcomes, neck disability index (NDI), solid bone fusion on cervical spine films, changes in posterior atlantodental interval (PADI), and surgical complications. Results : Solid bone fusion was documented radiologically in all cases, and PADI increased after surgery (p<0.05). All patients remained neurologically intact and showed improvement in NDI score (p<0.05). There were no surgical complications such as neural tissue or vertebral artery injury or instrument failure in the follow-up period. Conclusion : Posterior C1-2 fixation with a nitinol shape memory loop is a simple, less technically demanding method compared to the conventional technique and may avoid the instrument-related complications of posterior C1-2 screw and rod fixation. We introduce this technique as one of the treatment options for atlantoaxial instability.

• Journal of Korean Neurosurgical Society
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• v.39 no.3
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• pp.221-223
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• 2006

We report the case of a patient with a retro-odontoid synovial cyst, coupled with os odontoideum and atlantoaxial instability. We observed the regression of the cyst after C1-2 transarticular screw fixation and posterior wiring without direct surgical excision of the cyst on the follow-up MR images, which were obtained two and three months postoperatively. The myelopathic symptoms and signs of this patient were resolved by degrees.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1469-1475
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• 2000

Objective : The goal of this study was to evaluate the clinical outcome of the posterior C1-2 transarticular screw fixation without C1-2 sublaminar wiring in atlantoaxial instability. Methods : Between Apr. 1995 and Feb. 2000, we used this technique in treat randomly selected 17 patients (11 men, 6 women) who had atlantoaxial instability. The causes of instability were : type II-A odontoid process fracture(10 cases) ; type II-P odontoid process fracture(1 case) ; Os odontoideum(2 cases) ; transverse ligament laxity due to rheumatoid disease(1 case) ; and, transverse ligament injury without bone fracture(3 cases). All cases were operated with posterior C1-2 transarticular screw fixation with 3.5mm cortical screw and interlaminar iliac graft without sublaminar wire fixation. The mean follow-up period was 28 months(5 to 58 months) and the mean age at the time of operation was 41 years(15 to 68 years). All Patients were allowed to ambulate with Philadelphia neck collar on the first post-operation day. Results : Bony fusion was successfully achieved in all cases demonstrated at 3-month follow-up studies. There was no operative mortality or morbidity. Conclusion : The authors conclude that the posterior transarticular screw fixation without C1-2 sublaminar wiring provide adequate stability with high bony union rate in atlantoaxial instability of various causes.

• Journal of Korean Neurosurgical Society
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• v.55 no.5
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• pp.284-288
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• 2014

A rare case of atlantoaxial rotatory subluxation occurred after pediatric cervical spine surgery performed to remove a dumbbell-shaped meningioma at the level of the C1/C2 vertebrae. This case is classified as a post-surgical atlantoaxial rotatory subluxation, but has a very rare morphology that has not previously been reported. Although there are several reports about post-surgical atlantoaxial rotatory subluxation, an important point of this case is that it might be directly related to the spinal cord surgery in C1/C2 level. On day 6 after surgery, the patient presented with the Cock Robin position, and a computed tomography scan revealed a normal type of atlantoaxial rotatory subluxation. Manual reduction was performed followed by external fixation with a neck collar. About 7 months after the first surgery, the subluxation became severe, irreducible, and assumed an atypical form where the anterior tubercle of C1 migrated to a cranial position, and the posterior tubercle of C1 and the occipital bone leaned in a caudal direction. The pathogenic process suggested deformity of the occipital condyle and bilateral C2 superior facets with atlantooccipital subluxation. A second operation for reduction and fixation was performed, and the subluxation was stabilized by posterior fixation. We encountered an unusual case of a refractory subluxation that was associated with an atypical deformity of the upper spine. The case was successfully managed by posterior fixation.

• Journal of Korean Neurosurgical Society
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• v.41 no.2
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• pp.141-144
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• 2007

A vertebral arte [VA] injury presents a difficult problem in atlantoaxial fixation. Recent technical reports described posterior C2 fixation using bilateral, crossing C2 laminar screws. The translaminar screw technique has the advantages of producing little risk of VA injury and the unconstrained screw placement. In addition, biomechanical studies have demonstrated the potential of the translaminar screw technique to provide a firmer construct that is equivalent to methods currently used. We report the successful treatment of C1-2 instability with a left-side high-riding VA. Because of the potential risk of VA injury, we performed a posterior C1-2 fixation with a combination of pedicle screws and a laminar screw in C2. We first placed bilateral C1 lateral mass screws and a right-side C2 pedicle screw. However, placement of the left- side C2 pedicle screw was technically difficult due to a narrow isthmus and pedicle. A laminar screw was inserted instead and authors believe that this posterior C1-C2 fixation with a combination of pedicle screws and a laminar screw in C2 can be a useful alternative technique for the treatment of C1-C2 instability in the presence of a unilateral high-riding VA.

• Journal of Korean Neurosurgical Society
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• v.51 no.3
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• pp.177-181
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• 2012

We present a case of an athetoid cerebral palsy with quadriparesis caused by kyphotic deformity of the cervical spine, severe spinal stenosis at the cervicomedullary junction, and atlantoaxial instability. The patient improved after the first surgery, which included a C1 total laminectomy and C-arm guided righ side unilateral C1-2 transarticular screw fixation. C1-2 fixation was not performed on the other side because of an aberrant and dominant vertebral artery (VA). Eight months after the first operation, the patient required revision surgery for persistent neck pain and screw malposition. We used intraoperative VA angiography with simultaneous fluoroscopy for precise image guidance during bilateral C1-2 transarticular screw fixation. Intraoperative VA angiography allowed the accurate insertion of screws, and can therefore be used to avoid VA injury during C1-2 transarticular screw fixation in comorbid patients with atlantoaxial deformities.