• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.571-577
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• 2008

Root fracture of primary teeth is relatively uncommon because the more pliable alveolar bone allows displacement of the tooth. Root fracture of primary teeth is occupied $2{\sim}7%$ in trauma pattern of primary teeth. A horizontal root fracture is classified based on the location of the fracture in relation to the root tip : the apical third, middle third, or cervical third of the root. The prognosis worsens the further cervically the fracture has occurrer. Root fracture of primary teeth should be treated by splinting the incisor to the adjacent normal teeth with a resin-wire splint for $8{\sim}12$ weeks. However, if a portion of the root is abscessed or extremely mobile, it can be extracted, and the remaining root fragment will resorb normally. For coronal third fracture in primary teeth, the coronal third is extracted, leaving the apical portion of the root to resorb normally. These root fracture cases of primary teeth were treated by resin-wire splinting despite extremely mobile coronal fragment. Even though they seems like healing well, They need to be monitored regularly until their successors erupt.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.528-533
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• 2015

Objective : We sought to examine anatomic variations of the atlas and the clinical significance of these variations. Methods : We retrospectively reviewed 1029 cervical 3-dimensional (3D) CT images. Cervical 3D CT was performed between November 2011 and August 2014. Arcuate foramina were classified as partial or complete and left and/or right. Occipitalization of the atlas was classified in accordance with criteria specified by Mudaliar et al. Posterior arch defects of the atlas were classified in accordance with criteria specified by Currarino et al. Results : One hundred and eight vertebrae (108/1029, 10.5%) showed an arcuate foramen. Bilateral arcuate foramina were present in 41 of these vertebrae and the remaining 67 arcuate foramina were unilateral (right 31, left 36). Right-side arcuate foramina were partial on 18 sides and complete on 54 sides. Left-side arcuate foramina were partial on 24 sides and complete on 53 sides. One case of atlas assimilation was found. Twelve patients (12/1029, 1.17%) had a defect of the atlantal posterior arch. Nine of these patients (9/1029, 0.87%) had a type A posterior arch defect. We also identified one type B, one type D, and one type E defect. Conclusion : Preoperative diagnosis of occipitalization of the atlas and arcuate foramina using 3D CT is of paramount importance in avoiding neurovascular injury during surgery. It is important to be aware of posterior arch defects of the atlas because they may be misdiagnosed as a fracture.

• Journal of Korean Neurosurgical Society
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• v.56 no.4
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• pp.348-352
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• 2014

High-flow vertebral arteriovenous fistulas (VAVF) are rare complications of cervical spine surgery and characterized by iatrogenic direct-communication of the extracranial vertebral artery (VA) to the surrounding venous plexuses. The authors describe two patients with VAVF presenting with ischemic presentation after C1 pedicle screw insertion for a treatment of C2 fracture and nontraumatic atlatoaxial subluxation. The first patient presented with drowsy consciousness with blurred vision. The diffusion MRI showed an acute infarction on bilateral cerebellum and occipital lobes. The second patient presented with pulsatile tinnitus, dysarthria and a subjective weakness and numbness of extremities. In both cases, digital subtraction angiography demonstrated high-flow direct VAVFs adjacent to C1 screws. The VAVF of the second case occurred near the left posterior inferior cerebellar artery originated from the persistent first intersegmental artery of the left VA. Both cases were successfully treated by complete occlusion of the fistulous portion and the involved segment of the left VA using endovascular coil embolization. The authors reviewed the VAVFs after the upper-cervical spine surgery including C1 screw insertion and the feasibility with the attention notes of its endovascular treatment.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.188-192
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• 1998

A 3-month old female Holstein calf was presented with about a month history of intermittent dyspnea, exercise intolerance and cough despite antibiotic therapy. Auscultation revealed prominent inspiratory and exploratory crackles and wheezes over the causal cervical trachea which were heard equally over both side of the chest.4 modest amount of forced exercise caused severe respiratory distress with stertorous noise and occasional honkinglike cough. Pasteurella spp. was isolated on the nasal swabs and a hemogram showed mild leucocytosis with a mature neutrophilia and mild monocytosis. Lateral radiographs of the neck and thorax revealed a marked narrowing of the tracheal lumen extending from the level of the fifth cervical to the second thoracic vertebra, and the lung field was judged to be within normal limitsi except very mild peribronchial thickening. The hypertrophic non-union fractures of the first pair of ribs were noted with a well delineatedr redundant callus formations and also the completely healed fractures were found on the next seven pairs of ribs. A diagnosis of tracheal collapse was made, which is thought to be a traumatic origin.4 poor prognosis was given. The calf was euthanatized and necropsied. The tracheal rings from 19th to 41s1 were collapsed dorsoventrally. Histologically, there was no difference between the collapsed and normal areas of the tracheae except the folding mucosal layer in the collapsed area. This report details a case of tracheal collapse in a calli and the literature is reviewed.

• Journal of Korean Neurosurgical Society
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• v.56 no.2
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• pp.108-113
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• 2014

Objective : Ankylosing spondylitis is an inflammatory rheumatic disease mainly affecting the axial skeleton. The rigid spine may secondarily develop osteoporosis, further increasing the risk of spinal fracture. In this study, we reviewed fractures in patients with ankylosing spondylitis that had been clinically diagnosed to better define the mechanism of injury, associated neurological deficit, predisposing factors, and management strategies. Methods : Between January 2003 and December 2013, 12 patients with 13 fractures with neurological complications were treated. Neuroimaging evaluation was obtained in all patients by using plain radiography, CT scan, and MR imaging. The ASIA Impairment Scale was used in order to evaluate the neurologic status of the patients. Management was based on the presence or absence of spinal instability. Results : A total of 9 cervical and 4 thoracolumbar fractures were identified in a review of patients in whom ankylosing spondylitis had been diagnosed. Of these, 7 fractures were associated with a hyperextension mechanism. 10 cases resulted in a fracture by minor trauma. Posttraumatic neurological deficits were demonstrated in 11 cases and neurological improvement after surgery was observed in 5 of these cases. Conclusions : Patients with ankylosing spondylitis are highly susceptible to spinal fracture and spinal cord injury even after only mild trauma. Initial CT or MR imaging of the whole spine is recommended even if the patient's symptoms are mild. The patient should also have early surgical stabilization to correct spinal deformity and avoid worsening of the patient's neurological status.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.204-209
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• 2012

Surgical extrusion, immediate extrusion following tooth luxation, is a method to preserve one's natural tooth and achieve esthetic restoration without additional periodontal surgery when subgingival dental caries or crown fracture occurs. A 16-year-old male was referred to the clinic from the department of operative dentistry for the esthetic restoration of maxillary left lateral incisor. Due to the crown to root fracture, the tooth was endodontically treated with a buccal crown length of 4 mm. When the palatal flap was elevated, the mesiopalatal cervical fracture area was situated 3-4 mm subgingivally. Crown lengthening was achieved through surgical extrusion. After 3 months of clinical observation and provisional restoration, the maxillary left central incisor was restored with all ceramic crown and obtained a satisfactory clinical result.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.257-266
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• 2010

The purpose of this study was to determine the effect of post types and sizes on fracture resistance in immature tooth model with various restorative techniques. Bovine incisors were sectioned 8 mm above and 12 mm below the cementoenamel junction to simulate immature tooth model. To compare various post-and-core restorations, canals were restored with gutta-percha and resin core, or reinforced dentin wall with dual-cured resin composite, followed by placement of D.T. LIGHT-POST, ParaPost XT, and various sizes of EverStick Post individually. All of specimens were stored in the distilled water for 72 hours and underwent 6,000 thermal cycles. After simulation of periodontal ligament structure with polyether impression material, compressive load was applied at 45 degrees to the long axis of the specimen until fracture was occurred. Experimental groups reinforced with post and composite resin were shown significantly higher fracture strength than gutta-percha group without post placement (p < 0.05). Most specimens fractured limited to cervical third of roots. Post types did not influence on fracture resistance and fracture level significantly when cement space was filled with dual-cured resin composite. In addition, no statistically significant differences were seen between customized and standardized glass fiber posts, which cement spaces were filled with resin cement or composite resin individually. Therefore, root reinforcement procedures as above in immature teeth improved fracture resistance regardless of post types and sizes.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.1
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• pp.9-17
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• 2017

Purpose: The purpose of this study was to evaluate the fracture strength of straight and angled zirconia abutments for internal hex and external hex implants. Materials and methods: Twenty internal hex implants and 20 external hex implants were prepared. The prefabricated straight zirconia abutments and 17-degree-angled zirconia abutments were connected to those 40 implants. The specimens were classified into 4 groups depending on the connection type and abutment angulation; internal hex implant/straight abutment, group INS; internal hex implant/angled abutment, group INA; external hex implant/straight abutment, group EXS; external hex implant/angled abutment, group EXA. All specimens were loaded at a 30-degree angle with a crosshead speed of 1 mm/min using universal testing machine. The fracture loads were analyzed using 2-way ANOVA and independent t-test (${\alpha}=.05$). Results: The mean fracture load for INS was 955.91 N, 933.65 N for INA, 1267.20 N for EXS, and 1405.93 N for EXA. External hex implant showed a significantly higher fracture load, as compared to internal hex implant (P < .001). No significant differences in fracture loads were observed between the straight and angled abutment in internal hex implants (P = .747) and external hex implants (P = .222). Internal hexes of abutments were fractured horizontally in internal connection implants, while lingual cervical neck portions were fractured in external connection implants. Conclusion: The zirconia abutments with external hex implants showed significantly higher fracture strength than those with internal hex implants. However there was no difference in fracture strength between the straight and 17-degree-angled zirconia abutment connected to both implant systems.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1389-1395
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• 2000

A case report of a post-traumatic syringomyelia in a 29-year old male, developed 15 years after an L1 burst fracture, is presented. On preoperative MRI, the syrinx extended cephalad above the fracture site through the whole thoracic and cervical cord. Serial myelo-CT was performed to evaluate the dynamics of CSF. It was managed by lysis of the arachnoid adhesions, syringosubarachnoid shunt, and expansile duraplasty. After surgery, the patient's symptoms improved, and marked decrease of the syrinx was seen on postoperative MRI. The pathophysiology, the role of preoperative diagnostic methods especially serial myelo-CT, and the contmporary management modalities for posttraumatic syringomyelia is reviewed along with the pertinent literature.

• 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.