• Journal of Korean Neurosurgical Society
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• v.53 no.4
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• pp.223-227
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• 2013

Objective : Although there is no consensus on the ideal treatment of the craniocervical instability, biomechanical stabilization and bone fusion can be induced through occipito-cervical fusion (OCF). The authors conducted this study to evaluate efficacy of OCF, as well as to explore methods in reducing complications. Methods : A total of 16 cases with craniocervical instability underwent OCF since the year 2002. The mean age of the patients was 51.5 years with a mean follow-up period of 34.9 months. The subjects were compared using lateral X-ray taken before the operation, after the operation, and during last follow-up. The Nurick score was used to assess neurological function pre and postoperatively. Results : All patients showed improvements in myelopathic symptoms after the operation. The mean preoperative Nurick score was 3.1. At the end of follow-up after surgery, the mean Nurick score was 2.0. After surgery, most patients' posterior occipito-cervical angle entered the normal range as the pre operation angle decresed from 121 to 114 degree. There were three cases with complications, such as, vertebral artery injury, occipital screw failure and wound infection. In two cases with cerebral palsy, occipital screw failures occurred. But, reoperation was performed in one case. Conclusion : OCF is an effective method in treating craniocervical instability. However, the complication rate can be quite high when performing OCF in patients with cerebral palsy, rheumatoid arthritis. Much precaution should be taken when performing this procedure on high risk patients.

• Journal of Korean Neurosurgical Society
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• v.52 no.2
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• pp.114-119
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• 2012

Objective : The purpose of this study was 1) to analyze clinically-executed cervical lateral mass screw fixation by the Kim's technique as suggested in the previous morphometric and cadaveric study and 2) to examine various complications and bicortical purchase that are important for b-one fusion. Methods : A retrospective study was done on the charts, operative records, radiographs, and clinical follow up of thirty-nine patients. One hundred and seventy-eight lateral mass screws were analyzed. The spinal nerve injury, violation of the facet joint, vertebral artery injury, and the bicortical purchases were examined at each lateral mass. Results : All thirty-nine patients received instrumentations with poly axial screws and rod systems, in which one hundred and seventy-eight screws in total. No vertebral artery injury or nerve root injury were observed. Sixteen facet joint violations were observed (9.0%). Bicortical purchases were achieved on one hundred and fifty-six (87.6%). Bone fusion was achieved in all patients. Conclusion : The advantages of the Kim's technique are that it is performed by using given anatomical structures and that the complication rate is as low as those of other known techniques. The Kim's technique can be performed easily and safely without fluoroscopic assistance for the treatment of many cervical diseases.

• Journal of the Korean Arthroscopy Society
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• v.14 no.2
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• pp.131-134
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• 2010

Inappropriate treatment of osteochondral fracture can cause osteoarthritis, pain, functional disorder. With large osteochondral fracture, reduction and fixation of the fragment using metal implant. However, when the bone fragment had less than 2mm, the fragment extracted because of difficulty of fragment fixation. Authors treated patients with fracture fragment thickness less than 2mm of osteochondral dissecans in medial femoral condyle and patella fracture using biodegradable meniscus screw, and then we obtained good result.

• Clinics in Shoulder and Elbow
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• v.19 no.1
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• pp.8-14
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• 2016

Background: The purpose of this study was to investigate the difference between two nailing approaches of intramedullary screw fixation, the retrograde nailing versus the anterograde nailing, on the radiological and clinical outcomes in patients with clavicle shaft fractures. Methods: From April 2002 to August 2014, we enrolled a total of 22 patients with clavicle shaft fractures to participate in this study. Twelve patients received retrograde intramedullary nailing and 10 received anterograde nailing. The average duration of follow-up was 12 months. In all the patients, we took follow-up radiographs of the anteroposterior and the axial views to assess the postoperative radiological outcomes. We measured the visual analogue scale (VAS) score, American Shoulder and Elbow Surgeons (ASES) score, and the range of motion (ROM). Results: Clinically, we did not find a statistically significant difference in the retrograde group and the anterograde group in terms of the duration to bone union, the VAS score the ASES score and the ROMs. Radiologically, we found that the difference in the clavicle shortening of the affected arm and the unaffected arm did not show a statistically significant difference at the immediate postoperative assessment. we found that the difference in the clavicle shortening of the affected arm between the immediate postoperative and the final follow-up value did not show a statistically significant difference. Conclusions: We found that both the retrograde nailing and the anterograde nailing gave a favorable outcome for clavicle shaft fractures. Although we saw evidence of clavicle shortening after intramedullary screw fixation, this was not a factor that influenced clinical outcome.

• Journal of Trauma and Injury
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• v.36 no.3
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• pp.196-205
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• 2023

Purpose: Surgical stabilization of rib fractures (SSRF) is widely used in patients with flail chests, and several studies have reported the efficacy of SSRF even in multiple rib fractures. However, few reports have discussed the hardware failure (HF) of implanted plates. We aimed to evaluate the clinical characteristics of patients with HF after SSRF and further investigate the related factors. Methods: We retrospectively reviewed the electronic medical records of patients who underwent SSRF for multiple rib fractures at a level I trauma center in Korea between January 2014 and January 2021. We defined HF as the unintentional loosening of screws, dislocation, or breakage of the implanted plates. The baseline characteristics, surgical outcomes, and types of HF were assessed. Results: During the study period, 728 patients underwent SSRF, of whom 80 (10.9%) were diagnosed with HF. The mean age of HF patients was 56.5±13.6 years, and 66 (82.5%) were men. There were 59 cases (73.8%) of screw loosening, 21 (26.3%) of plate breakage, 17 (21.3%) of screw migration, and seven (8.8%) of plate dislocation. Nine patients (11.3%) experienced wound infection, and 35 patients (43.8%) experienced chronic pain. A total of 21 patients (26.3%) underwent reoperation for plate removal. The patients in the reoperation group were significantly younger, had fewer fractures and plates, underwent costal fixation, and had a longer follow-up. There were no significant differences in subjective chest symptoms or lung capacity. Conclusions: HF after SSRF occurred in 10.9% of the cases, and screw loosening was the most common. Further longitudinal studies are needed to identify risk factors for SSRF failure.

• Journal of Korean Foot and Ankle Society
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• v.20 no.2
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• pp.67-72
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• 2016

Purpose: The purpose of this study was to assess the 2-year follow-up results of patients with a trimalleolar fracture, who had undergone an anterior incision cannulated screw fixation of the posterior malleolar fragment, which had more than 25% of articular involvement or had no cortical continuity with the distal tibia. Materials and Methods: Among 28 patients with a trimalleolar fracture who had undergone fixation of the posterior malleolar fragment between February 2005 and February 2010, 14 patients, who underwent an anterior incision cannulated screw fixation of posterior malleolar fragment and were followed-up for more than 2 years, were selected. The postoperative clinical and radiological findings immediately and at the 1- and 2-year follow-up were compared. The clinical findings were evaluated as American Orthopaedic Foot and Ankle Society (AOFAS) score. The radiological assessment was evaluated as the maintenance of reduction, period to bone union, and the presence of nonunion, malunion, and complications. Results: The clinical outcome by mean AOFAS score revealed 83.0 points in the group with preoperative displacement below 2 mm and 80.7 points in the group with preoperative displacement above 2 mm postoperatively. The mean AOFAS score was 91.7 and 93.1 points in the group with preoperative displacement below 2 mm on 1- and 2-year follow-up, respectively, and 89.8 and 91.7 points in group with the preoperative displacement above 2 mm on 1- and 2-year follow-up, respectively. After a 2-year follow-up among 14 cases selected for this study, 13 cases showed an excellent reduction state and only 1 case (7.1%) showed a displacement of more than 2 mm. No complication were encountered in the group with preoperative displacement below 2 mm. On the other hand, among 8 patients in the group with preoperative displacement above 2 mm, there were 3 with limitations of the range of motion of the ankle joint (37.5%) and 1 post-traumatic arthritis (12.5%) at the 2-year follow-up. Conclusion: Anterior incision cannulated screw fixation of the posterior malleolar fragment could be a valuable method for the treatment of trimalleolar fractures that provides satisfactory results.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.3
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• pp.157-170
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• 1993

To prove the effct of semi-rigid fixation which utilize wire and rigid fixation which utilizes miniplate toward cranio-facial growth and development of growing children for teenagers, 28 rabbits-6 weeks, about 1.5kg-were experimented. They were classified three groups the semi-rigid group was 12 rabbits which were fixed with 26 gauge stainless steel wire to cross a fronto-nasal suture, the rigid group was the other 12 rabbits which were fixed with miniplate and screw, the control group was 4 rabbits which were get rid of only periosteum. The sample of fronto-nasal of rabbits which were sacrified after 2 weeks, 4 weeks, 8 weeks, and 12 weeks of the operation were investigated and made a comparative study with the light microscops. 1. At the control group, the central part of bony suture was connected with colagen bundle, the osteoblastic layer was investigated at the bony ending, new bone which covered the inside and outside faces of the bone suture was formed between periosteum. 2. Two weeks later from the experiment, ran slightly irregularly the collagen bundle which connects both bony endings of the rigid group. 3. Four weeks later from the experiment, collagen bundle of bone surface were arranged parally a little and comparing to the semi-rigid group, newly formed woven bone of surface of the adjacent bone was made obviously a little. 4. Eight weeks later from the experiment, collagen bundle which is located between both bony ending become close. Both the semi-rigid group and the rigid group showed significant formation of new bone at the periosteum and the bone surface. 12 weeks later from the experiment, both the semi-rigid group and the rigid group showed the regular running in the collagen bundle and smooth, dense periosteum. Then they assumed a similar aspect of the control group. I think that it does not give the influence to the cranio-facial growth of children or teenager to utilize a rigid fixation for a short period. Because as the time goes on, the surface of the bone suture was recovered and adjacent bone surface of the miniplate fixation showed compensatory growth, although both the semi-rigid group which utilized wire and rigid group which utilized a miniplate brought about the change of the area of the bone suture at the early period.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.3
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• pp.274-287
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• 2000

The use of dental implants has increased tremendously in recent years and is expected to increase even more in the future. The successful outcome of any implant procedure is surely dependent on interrelationship of the various components of an equation that includes biocompatibility of implant material, macroscopic and microscopic nature of the implant surface, the status of implant bed, surgical technique, undisturbed healing phase and subsequent prosthetic design and long-term loading phase. The purpose of this study was to clarify the effects of adrenalectomy on the osseointegration of pure titanium implants. Seventy rats, 11 weeks of age, were divided into two groups : an adrenalectomized group and a control group. Titanium screw implant(diameter, 2.0mm; length, 3.5mm) was placed into left tibia of 70 rats, 35 in control group and 35 in the experimental group. The rats were sacrificed at different time interval (1, 2, 3, 4, 6, 8, and 12 weeks after implantation) for histopathologic observation, histomorphometric analysis and immunohistochemistry with fibronectin and CD44 antibody. The results obtained from this study were as follows: 1. Histopathogically, findings, newly formed bone was seen at 3 weeks control group and became lamellar bone at 12 weeks. At 6 weeks, lipocytes were observed in bone marrow space. Thickness of regenerated trabecular bone increased till 6 weeks after then, that decreased gradually. 2. By histomorphometric analysis, marrow bone density and contact ratio of marrow bone to implant decreased significantly from 8 to 12 weeks in experimental group compared to control group and also total bone to implant contact ratio decreased significantly from 4 to 12 weeks in experimental group compared to control group. 3. Fibronectin immunoreactivity was very strong at 3 and 4 weeks control group. And after that reduced gradually. But it was continuously strong from 1 to 12 weeks experimental group. 4. CD44 immunoreactivity was very strong in the newly formed osteoblasts at 3 and 4 weeks control group. But it reacted minimally later. However, it reacted continuously strong from 3 to 12 weeks experimental group. From these results, bone to implant contact ratio decreased gradually from 4 weeks in adrenalectomized group compared to control group. CD44 and fibronectin immunoreactivities were strong at all times in adrenalectomized rats. Therefore, it could be stated that immature bone remained continuously for a long time and not readily proceeded into mature status.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.228-239
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• 2008

Objective: The aim of this study was to evaluate the strain induced in the cortical bone surrounding an orthodontic microimplant during insertion. Methods: A 3D finite element method was used to model the insertion of a microimplant (AbsoAnchor SH1312-7, Dentos Co., Daegu, Korea) Into 1 mm thick cortical bone with a pre-drilled hole of 0.9 mm in diameter. A total of 1,800 analysis steps was used to simulate the 10 turns and 5 mm advancement of the microimplant. A series of remesh in the cortical bone was allowed to accommodate the change in the geometry accompanied by the implant insertion. Results: Bone strains of well higher than 4,000 microstrain, the reported upper limit for normal bone remodeling, was observed in the bone along the whole length of the microimplant. At the bone in the vicinity of the screw tip, strains of higher than 100% was recorded. The insertion torque was calculated at approximately 1.2 Ncm which was slightly lower than those measured from the animal experiment using rabbit tibias. Conclusions: The insertion process of a microimplant was successfully simulated using the 3D finite element method which showed that bone strains from a microimplant insertion might have a negative impact on physiological remodeling of bone.

• The korean journal of orthodontics
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• v.37 no.3 s.122
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• pp.171-181
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• 2007

Objective: The present study was aimed at an analytical formulation of the micro-implant related torque as a function of implant size, i.e. the diameter and length, screw size, and the bony resistance at the implant to bone interface. Methods: The resistance at the implant to cancellous bone interface $(S_{can})$ was assumed to be in the range of 1.0-2.5 MPa. Micro-implant model of Absoanchor (Dentos Inc. Daegu, Korea) was used in the course of the analysis. Results: The results showed that the torque was a strong function of diameter, length, and the screw height. As the diameter increased and as the screw size decreased, the torque index decreased. However the strength index was a different function of the implant and bone factors. The whole Absoanchor implant models were within the safe region when the resistance at the implant/cancellous bone $(=S_{can})$ was 1.0 or less. Conclusion: For bone with $S_{can}$ of 1.5 MPa, the cervical diameter should be greater than 1.5 mm if micro-implant models of 12 mm long are to be placed. For $S_{can}$ of 2.0 MPa, micro-implant models of larger cervical diameter than 1.5 mm were found to be safe only if the endosseous length was less than 8 mm.