• 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 Veterinary Clinics
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• v.35 no.1
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• pp.30-33
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• 2018

A 7-month-old female Bichon Frise, displaying neck pain and ataxia, was diagnosed with craniocervical junction abonormality (CJA), along with atlantoaxial subluxation. Surgical fixation of the atlantoaxial subluxation was performed, using cortical screws and bone cement, along with an odontoidectomy. After surgery, nonsteroidal anti-inflammatory medication was prescribed for pain control, and a loose bandage was applied to the neck. Mild ambulatory tetraparesis remained 1 week after surgery. Three weeks after surgery, the range of neck motion was near normal, and clinical signs had improved. CJA should be considered as a differential diagnosis in dogs with cervical myelopathy. Surgical stabilization using cortical screws and bone cement through a ventral approach can be successful in dogs with CJA and atlantoaxial subluxation.

• Journal of Korean Neurosurgical Society
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• v.52 no.2
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• pp.120-125
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• 2012

Objective : To investigate the feasibility of C1 lateral mass screw and C2 pedicle screw with polyaxial screw and rod system supplemented with miniplate for interlaminar fusion to treat various atlantoaxial instabilities. Methods : After posterior atlantoaxial fixation with lateral mass screw in the atlas and pedicle screw in the axis, we used 2 miniplates to fixate interlaminar iliac bone graft instead of sublaminar wiring. We performed this procedure in thirteen patients who had atlantoaxial instabilities and retrospectively evaluated the bone fusion rate and complications. Results : By using this method, we have achieved excellent bone fusion comparing with the result of other methods without any complications related to this procedure. Conclusion : C1 lateral mass screw and C2 pedicle screw with polyaxial screw and rod system supplemented with miniplate for interlaminar fusion may be an efficient alternative method to treat various atlantoaxial instabilities.

• Journal of Veterinary Clinics
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• v.14 no.1
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• pp.126-130
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• 1997

10개월경의 그리폰 벤딘 수컷 강아지가 8개월경부터 점점 운동 실조 및 마비증상을 나타내어 머독대학 동물병원에 내원 하였다. 내원 했을 때 주변에 매우 민감한 반응과 경계를 늦추지 않았지만 호흡과 심박수 및 체온은 정상이었다. 일반 방사선 사진 및 척수조영사진(myelography)을 촬영하여 확인한 결과 환축추의 불안정에 따른 척수의 복측 압박을 확인할 수 있었다. 외과적 고정은 복측 접근을 통하여 2개의 키르크너 강선(Kirschner wire)과 자가골이식을 실시하였으며 8주동안 외부 고정을 하였다. 수술 후 5개월 동안 지켜본 결과 증상은 꾸준히 좋아졌으며 환축추 관절으 관절고정술(arthrodesis)은 완벽한 고정을 유지하고 있었다.

• Journal of Korean Neurosurgical Society
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• v.47 no.3
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• pp.221-223
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• 2010

C1 lateral mass and C2 pedicle (C1LM-C2P) fixation is a relatively new technique for atlantoaxial stabilization. Complications from C1LM-C2P fixation have been rarely reported. The authors report unilateral rod migration into the posterior fossa as a rare complication after this posterior C1-C2 stabilization technique. A 23-year-old man suffered severe head trauma and cervical spine injury after vehicle accident. He was unconscious for 2 months and regained consciousness. He underwent C1LM-C2P fixation for stabilization of type II odontoid process fracture described by Harms. The patient recovered without a major complication. Twenty months after operation, brain computed tomogram performed at psychology department for disability evaluation showed rod migration into the right cerebellar hemisphere. The patient had mild occipital headache and dizziness only regarding the misplaced rod. He refused further operation for rod removal. To our knowledge, this complication is the first report regarding rod migration after Harms method. We should be kept in mind the possibility of rod migration, and C1LM-C2P fixation should be performed with meticulous technique and long-term follow-up.

• Journal of Korean Neurosurgical Society
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• v.55 no.5
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• pp.255-260
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• 2014

Objective : The purpose of this study was to compare the radiological and neurological outcomes between two atlantoaxial fusion method for atlantoaxial stabilization; C1 lateral mass-C2 pedicle screws (screw-rod constructs, SRC) versus C1-2 transarticular screws (TAS). Methods : Forty-one patients in whom atlantoaxial instability was treated with atlantoaxial fixation by SRC group (27 patients, from March 2005 to May 2011) or TAS group (14 patients, from May 2000 to December 2005) were retrospectively reviewed. Numeric rating scale (NRS) for pain assessment, Oswestry disability index (ODI), and Frankel grade were also checked for neurological outcome. In radiologic outcome assessment, proper screw position and fusion rate were checked. Perioperative parameters such as blood loss during operation, operation time, and radiation exposure time were also reviewed. Results : The improvement of NRS and ODI were not different between both groups significantly. Good to excellent response in Frankel grade is shown similarly in both groups. Proper screw position and fusion rate were also observed similarly between two groups. Total bleeding amount during operation is lesser in SRC group than TAS group, but not significantly (p=0.06). Operation time and X-ray exposure time were shorter in SRC group than in TAS group (all p<0.001). Conclusion : Both TAS and SRC could be selected as safe and effective treatment options for C1-2 instability. But the perioperative result, which is technical demanding and X-ray exposure might be expected better in SRC group compared to TAS group.

• Journal of Korean Neurosurgical Society
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• v.61 no.2
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• pp.277-281
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• 2018

Objective : Craniovertebral junctional anomalies constitute a technical challenge. Surgical opening of atlantoaxial joint region is a complex procedure especially in patients with nuchal deformity like basilar invagination. This region has actually very complicated anatomical and functional characteristics, including multiple joints providing extension, flexion, and wide rotation. In fact, it is also a bottleneck region where bones, neural structures, and blood vessels are located. Stabilization surgery regarding this region should consider the fact that the area exposes excessive and life-long stress due to complex movements and human posture. Therefore, all options should be considered for surgical stabilization, and they could be interchanged during the surgery, if required. Methods : A 53-year-old male patient applied to outpatients' clinic with complaints of head and neck pain persisting for a long time. Physical examination was normal except increased deep tendon reflexes. The patient was on long-term corticosteroid due to an allergic disease. Magnetic resonance imaging and computed tomography findings indicated basilar invagination and atlantoaxial dislocation.The patient underwent C0-C3-C4 (lateral mass) and additional C0-C2 (translaminar) stabilization surgery. Results : In routine practice, the sites where rods are bound to occipital plates were placed as paramedian. Instead, we inserted lateral mass screw to the sites where occipital screws were inserted on the occipital plate, thereby creating a site where extra rod could be bound.When C2 translaminar screw is inserted, screw caps remain on the median plane, which makes them difficult to bind to contralateral system. These bind directly to occipital plate without any connection from this region to the contralateral system.Advantages of this technique include easy insertion of C2 translaminar screws, presence of increased screw sizes, and exclusion of pullout forces onto the screw from neck movements. Another advantage of the technique is the median placement of the rod; i.e., thick part of the occipital bone is in alignment with axial loading. Conclusion : We believe that this technique, which could be easily performed as adjuvant to classical stabilization surgery with no need for special screw and rod, may improve distraction force in patients with low bone density.

• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.341-347
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• 2011

Objective : The purpose of this retrospective study was to evaluate the efficacy and safety of atlantoaxial stabilization using a new entry point for C2 pedicle screw fixation. Methods : Data were collected from 44 patients undergoing posterior C1 lateral mass screw and C2 screw fixation. The 20 cases were approached by the Harms entry point, 21 by the inferolateral point, and three by pars screw. The new inferolateral entry point of the C2 pedicle was located about 3-5 mm medial to the lateral border of the C2 lateral mass and 5-7 mm superior to the inferior border of the C2-3 facet joint. The screw was inserted at an angle $30^{\circ}$ to $45^{\circ}$ toward the midline in the transverse plane and $40^{\circ}$ to $50^{\circ}$ cephalad in the sagittal plane. Patients received followed-up with clinical examinations, radiographs and/or CT scans. Results : There were 28 males and 16 females. No neurological deterioration or vertebral artery injuries were observed. Five cases showed malpositioned screws (2.84%), with four of the screws showing cortical breaches of the transverse foramen. There were no clinical consequences for these five patients. One screw in the C1 lateral mass had a medial cortical breach. None of the screws were malpositioned in patients treated using the new entry point. There was a significant relationship between two group (p=0.036). Conclusion : Posterior C1-2 screw fixation can be performed safely using the new inferolateral entry point for C2 pedicle screw fixation for the treatment of high cervical lesions.

• Journal of Veterinary Clinics
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• v.25 no.2
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• pp.131-135
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• 2008

A 5-year-old Chihuahua dog was evaluated for a tetraparesis. The dog was presented with a non-ambulatory tetraparesis and neck pain. Radiography demonstrated an atlantoaxial (AA) subluxation and increased distance between the dorsal arch of the C1 and the dorsal spinous process of the C2. The AA joint was fixed with ventral transarticular fixation using two screws under fluoroscopic guidance. Neck brace was applied during 3 weeks post-operation. After 4 weeks, the dog was fully ambulatory with improved neurological function. Postoperative radiographs confirmed reduction of the luxation and no migration of screws. The dog showed complete resolution of clinical signs without signs of recurrence till 4 months after operation. Proper angulations of screws provided under fluoroscopic guidance, enabled adequate stabilization of the AA joints using ventral transarticular screw fixation which improved neurologic outcome of the patient.

• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.499-502
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• 2013

An eight-year-old, castrated male, Poodle dog was presented with a bite wound in the neck region. Clinical examination revealed non-ambulatory signs of tetraparesis with deep pain, and upper motor neuron changes in all limbs. Fractures of the transverse process of C1 and the dorsal spinous process of C2 were observed on the radiographs and the computed tomography (CT). Conservative therapy was performed for 1 week. However the neurological problems were not alleviated until 7 days after injury. The owners agreed to perform surgical stabilization. The surgical stabilization was performed 7 days after presentation. Ventral stabilization was performed with screws, K-wires and bone cement. The dog stood up independently after 4 weeks and was able to walk 6 weeks postoperatively. In this report we suggest that using combined stabilization techniques are effective for this type of cervical fracture in which the dorsal and ventral structures of the vertebra are severely disrupted.