• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.385-396
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• 2001

The purpose of this experiment was to examine the histological changes and the pattern of expression of proliferating cell nuclear antigen(PCNA) and type I collagen in the elongated bone affected by osteodistraction of the mandibular body in an adult canine model. Seven adult male mongrel dogs weighing over 20kg were used for this experiment. The author excluded 3 animals because they died before the planned time of sacrifice. The custom-made linear extraoral device and 4 bicortical fixation screws 2.3mm in diameter, 50mm in total length, 15mm in screw length were used in each animal. The distal part of the distractor produced a 0.75mm gap between proximal and distal bony segments every $360^{\circ}$ turn of the rotation rod of the device. The mandibular body of the right side from each animal was experimental side and the left side was left intact and served as control. At the experimental side, the mandibular body was osteotomized. After 5-day latency period, the segments were distracted with a rate of 1.1mm/day and a rhythm of two/day for ensuing 7 days. The animals were sacrificed at the 4th. 17th, and 32th day after the end of the distraction. The bony specimens were decalcified, embedded in paraffin, sectioned $5{\mu}m$ thick and stained with Masson trichrome and examined under the light microscope. The immunohistochemical examinations using anti-PCNA antibody and anti-type-I collagen antibody were performed to examine the pattern of the expression of PCNA and type I collagen, respectively. Results : 1. The mean increment of the distance between the proximal and distal screw-holding parts of the distractor was 6.8mm. The average elongation of the mandible in the experimental side was 5.3mm. The loss of elongation was 1.5mm in average. 2. New bone was already observed at the 4th. day after the end of distraction. But, bony union was not completed in the distraction gap at the 32th. day after the end of distraction by radiographic and microscopic examinations. 3. The expression rate of PCNA positive cells in the distraction gap had a tendency of decrease from 35.1-68.8% initially, to 49.1%, and finally to 17.6-27.2%. But at the final period, the tissue of the elongated gap still had the ability of cell proliferation. On the other hand, the expression of PCNA positive cells in the control side were negligible through the experimental period. 4. PCNA positive cells were observed primarily both at the central fibrous zone and at the region of just adjacent to CFZ which initiated new bone formation. 5. The expression pattern of the type I collagen was not zone-specific. They were observed diffusely throughout the elongation gap. 6. The predominant mechanism of new bone formation in the distraction gap was intramembranous. But, some of the regenerated bone was formed by endochondral ossification.

• The korean journal of orthodontics
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• v.38 no.5
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• pp.304-313
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• 2008

Objective: The purpose of this study was to evaluate the stress distribution in bone and displacement distribution of the miniscrew according to the length and number of the miniscrews used for the fixation of miniplate, and the direction of orthodontic force. Methods: Four types of finite element models were designed to show various lengths (6 mm, 4 mm) and number (3, 2) of 2 mm diameter miniscrew used for the fixation of six holes for a curvilinear miniplate. A traction force of 4 N was applied at $0^{\circ}$, $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$ to an imaginary axis connecting the two most distal unfixed holes of the miniplate. Results: The smaller the number of the miniscrew and the shorter the length of the miniscrew, the more the maximum von Mises stress in the bone and maximum displacement of the miniscrew increased. Most von Mises stress in the bone was absorbed in the cortical portion rather than in the cancellous portion. The more the angle of the applied force to the imaginary axis increased, the more the maximum von Mises stress in the bone and maximum displacement of the miniscrew increased. The maximum von Mises stress in the bone and maximum displacement of the miniscrew were measured around the most distal screw-fixed area. Condusions: The results suggest that the miniplate system should be positioned in the rigid cortical bone with 3 miniscrews of 2 mm diameter and 6 mm length, and its imaginary axis placed as parallel as possible to the direction of orthodontic force to obtain good primary stability.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.419-426
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• 2021

Purpose: In the surgical treatment of pyogenic lumbar spondylodiscitis, screw insertion at the affected vertebra has been avoided because of biofilm formation, and the risk of infection recurrence. The authors analyzed the success rate of infection treatment while minimizing the number of instrumented segments by inserting pedicle screws into the affected vertebrae. Therefore, this study examined the usefulness of this technique. Materials and Methods: From January 2000 to June 2018, among patients with pyogenic lumbar spondylodiscitis treated surgically, group A consisted of patients with pedicle screws inserted directly at the affected vertebrae (28 cases), and group B underwent fusion by inserting screws at the adjacent normal vertebrae due to bone destruction of the affected vertebral pedicle (20 cases). The classified clinical results were analyzed retrospectively. All patients were treated via the posterior-only approach, so the affected disc and sequestrum were removed. Posterior interbody fusion was performed with an autogenous strut bone graft, and the segments were then stabilized with pedicle screw systems. The hospitalization period, operation time, amount of blood loss, EQ-5D index, duration of intravenous antibiotics, and the clinical and radiological results were analyzed. Results: In group A, the number of instrumented segments, operation time, blood loss, and EQ-5D index at one month postoperatively showed significant improvement compared to group B. There were no significant differences in the duration of antibiotic use, hospitalization, radiological bone union time, sagittal angle correction rate, and recurrence rate. Conclusion: Minimal segmental fixation, in which pedicle screws were inserted directly into the affected vertebrae through the posterior approach, reduced the surgery time and blood loss, preserved the lumbar motion by minimizing fixed segments and showed rapid recovery without spreading or recurrence of infection. Therefore, this procedure recommended for the surgical treatment of lumbar pyogenic spondyodiscitis.

• Journal of Korean Neurosurgical Society
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• v.41 no.3
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• pp.166-170
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• 2007

Objective : The purpose of this study is to evaluate the clinical outcome of the two-stage operation for thoracic tuberculous spondylitis. Methods : Eleven patients [4 male, 7 female] with thoracic tuberculous spondylitis were treated with two-stage operation. First stage consisted of anterior debridement and interbody fusion using rib graft and second with posterior instrumentation with fusion. Mean age was 46 years, and mean follow-up period was 18 months. All patients were treated with 12 months of antituberculotic medication postoperatively, and evaluated before and after surgery with respect to pain level, neurological status, associated lesions, hematological parameters and change of kyphotic angle. Results : The associated lesions were pulmonary tuberculosis in 4 cases. There were no recurrences of infection and bone union was obtained within 6 months of the operation in all cases. Changes in the pain severity, neurological status, and hematological parameters demonstrated significant clinical improvement in all patients. The mean kyphotic angle was corrected from $17.8^{\circ}$ to $9.8^{\circ}$ after surgery. The most recent follow-up of the mean kyphotic angle was $12.3^{\circ}$, with a loss of correction of $2.5^{\circ}$. The preoperative VAS averaged to be 7.18 [range, 4-10]. It decreased significantly an average of 1.45 [p <0001]. Conclusion : These results indicate that two-stage surgical treatment for thoracic tuberculous spondylitis provid safe and satisfactory results. Spine instability and kyphosis can be also prevented by two-stage operation.

• Journal of Korean Neurosurgical Society
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• v.40 no.2
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• pp.84-89
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• 2006

Objective : The purpose of this study is to compare the outcomes of two methods for stabilization and fusion : Postero-Lateral Fusion [PLF, pedicle screw fixation with bone graft] and Posterior Lumbar Interbody Fusion [PLIF, cage insertion] for spinal stenosis and recurred disc herniation except degenerative spondylolisthesis. Methods : Seventy one patients who underwent PLF [n=36] or PLIF [n=35] between 1997 and 2001 were evaluated prospectively. These two groups were compared for the change of interbody space, the range of segmental angle, the angle of lumbar motion, and clinical outcomes by Prolo scale. Results : The mean follow-up period was 32.6 months. The PLIF group showed statistically significant increase of the interbody space after surgery. However, the difference in the change of interbody space between two groups was insignificant [P value=0.05]. The range of segmental angle was better in the PLIF group, but the difference in the change of segmental angle was not statistically significant [P value=0.0l7]. Angle of lumbar motion was similar in the two groups. Changes of Prolo economic scale were not statistically significant [P value=0.193]. The PLIF group showed statistically significant improvement in Prolo functional scale [P value=0.003]. In Prolo economic and functional scale, there were statistically significant relationships between follow-up duration [P value<0.001]. change of interbody space [P value<0.001], and range of segmental angle [P value<0.001]. Conclusion : Results of this study indicate that PLIF is superior to PLF in interbody space augmentation and clinical outcomes by Prolo functional scale. Analysis of clinical outcomes showed significant relationships among various factors [fusion type, follow-up duration, change of interbody space, and range of segmental angle]. Therefore, the authors recommend instrumented PLIF to offer better clinical outcomes in patients who needed instrumented lumbar fusion for spinal stenosis and recurred disc herniation.

• Journal of Biomedical Engineering Research
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• v.22 no.1
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• pp.69-80
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• 2001

본 연구에서는 환자의 골다공증 유무에 따른 내고정 장치 시술 직후 및 융합 후의 안정성을 평가하기 위해 다양한 하중 모드에서 C5-C6 운동분절의 생체역학적 거동을 분석하였다. 이러한 목적으로 먼저, C5-C6 경추부의 유한요소 모델을 구현하여 검증하였다. 모델의 결과는 기존 실험치와 유사하여 신뢰성이 부여되었다. 검증된 모델은 Smith-Robinson 방식으로 골이식물을 삽입한 후 전방 내고정 장치를 적용한 시술 상황을 재현하기 위해 수정되었다. 수정된 모델은 두 종류로 구현되었다. (1) 첫 번째 모델에서는, 시술 직후의 상황을 재현하기 위해 골이식물과 종판의 경계면에 접촉요소를 사용하였다. (2)두 번째 모델에서는 완전히 융합된 상황을 나타내기 위해 골이식물을 종판에 고정하였다. 골다공증의 효과를 예측하기 위하여 두 모델의 해면골에 대한 탄성계수를 변화시켰다(정상: 100MPa, 골다공증: 40MPa). 각 모델의 C5 주체의 상위면에 73.6N의 압축 하중을 가한 후에 108Nm의 굴곡/신전, 굽힘, 비틀림 하중을 가하였으며, C6 추체의 하단면은 모든 방향에 대하여 구속하였다. 전체적인 결과에 있어서 상대적 회전운동, 미끄럼운동, 골이식물 내에서의 von Mises 응력의 경우 정상 모델에 비해 골다공증 모델에서 증가함을 보였으며, 특히 시술 직후의 모델에서 비틀림 하중이 가해진 경우, 상대적 회전운동 및 미끄럼 운동이 가장 높게 예측되었다. 이는 골다공증환자에게 전방 내고정 장치를 시술한 경우 골이식물의 파단 및 유합의 실패가 비틀림 하중에서 발생할 수 있음을 나타낸다. 해면골의 von Mises 응력은 시술 직후에 골다공증 모델의 모든 하중 모드에서, 유합 후에는 굽힘 하중 외의 모든 하중에서 ultimate strength를 초과하는 것으로 나타나 골다공증 환자에게 screw의 해리가 발생할 가능성이 높은 것으로 예측되었다. 따라서 골다공증 환자에게 과도한 운동이 발생하지 않도록 하기 위해서 시술 후 세심한 주의와 halo 같은 견고한 정형술이 필요할 것으로 사료된다.

• Journal of Korean Orthopaedic Sports Medicine
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• v.3 no.2
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• pp.128-133
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• 2004

Purpose: This study was planned to evaluate complications? of posterior cruciate ligament (PCL) reconstruction with tibial inlay technique using autogenous bone-patellar tendon-bone graft. Materials and Methods: From September 1994 to January 2004, we analyzed surgical complications in fifty-seven patients with fifty-eight cases who underwent PCL reconstruction. Fifty of them were male and seven female. The mean age of the patients was 35(15$\~$73). Twenty eight cases of injury were isolated PCL, while thirty cases had associated injury of knee. The causes of injury were thirty-nine cases of traffic accident, seven sport injuries, seven fall down injuries, and five of others. The follow-up study was done at 4 weeks, 3 months,6 months and 1 year after surgery. KT-2000 arthrometer and posterior stress X-ray were used to examine the stability of the knee joint and the Lysholm Knee Score and a variety of clinical complications were evaluated. Results: Although the mean score of the preoperative Lysholm Knee Score was 43.2, the postoperative score was increased to 87.9. The preoperative mean value of knee stability using KT-2000 arthrometer was 8.75 mm(6.2$\~$14.3 mm) but the postoperative mean was 3.41 mm(2.1$\~$10.6 mm). The intraoperative complications were: one case of popliteal artery injury with compartment syndrome, one case of patellar fracture, two cases of 20$^{\circ}$ flexion loss, and two cases of anterior cortical penetration of the screw through proximal tibia during screw fixation. The postoperative complications were: eleven cases of knee instability, one case of patellar fracture, five cases of extension loss, thirteen cases of flexion loss, twenty-one cases of around knee pain and eight cases of kneeling pain. Conclusion: After PCL reconstruction with tibial inlay technique using autogenous bone-patella tendon-bone graft, complications were observed in this study. Careful attention during and after the operation, as well as rehabilitation must be required.

• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.327-335
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• 2019

Purpose: To investigate the radiological efficacy of polymethylmethacrylate (PMMA) augmentation of pedicle screw operation in osteoporotic vertebral compression fractures (OVCF) patients. Materials and Methods: Twenty OVCF patients, who underwent only posterior fusion using pedicle screws with PMMA augmentation, were included in the study. The mean follow-up period was 15.6 months. The demographic data, bone mineral density (BMD), fusion segments, number of pedicle screws, and amount of PMMA were reviewed as medical records. To analyze the radiological outcomes, the radiologic parameters were measured as the time serial follow-up (preoperation, immediately postoperation, postoperation 6 weeks, 3, 6 months, and 1 year follow-up). Results: A total of 20 patients were examined (16 females [80.0%]; mean age, 69.1±8.9 years). The average BMD was -2.5±0.9 g/cm². The average cement volume per vertebral body was 6.3 ml. The mean preoperative Cobb angle of focal kyphosis was 32.7°±7.0° and was improved significantly to 8.7°±6.9° postoperatively (p<0.001), with maintenance of the correction at the serial follow-up, postoperatively. The Cobb angle of instrumented kyphosis, wedge angle, and sagittal index showed similar patterns. In addition, the anterior part of fractured vertebral body height averaged 11.0±5.0 mm and was improved to 18.5±5.7 mm postoperatively (p=0.006), with maintenance of the improvement at the 3-month, 6-month, and 1-year follow-up. Conclusion: The reinforcement of pedicle screws using PMMA augmentation may be a feasible surgical technique for OVCF. Moreover, it appears to be appropriate for improving the focal thoracolumbar/lumbar kyphosis and is maintained well after surgery.

• Clinics in Shoulder and Elbow
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• v.15 no.1
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• pp.25-31
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• 2012

Purpose: The clinical and radiographic outcomes of the internal fixation, which were executed on patients over the age of 65 with proximal humerus fracture by using a polyaxial angular stable locking compression plate (Non-Contact-Bridging proximal humerus plate, Zimmer, Switzerland, NCB), were evaluated. Materials and Methods: Thirty two patients over the age of 65 among the proximal humerus fracture treated with NCB plate, between August 2007 and January 2011, were chosen as the subjects. The average age of patients was 71 years, and the average postoperative follow-up period was 11.5 months. The fractures included 14 two-part and 18 three-part fractures. The clinical results were evaluated, using the visual analog scale (VAS) score and the Constant score. The radiological results were evaluated by time to union and Paavolainen method, which measures the neck shaft angle. Results: At the last follow-up examination, the mean VAS score was 3 points and the mean Constant score was 64.5 points, with bone union achieved after the average of 16.2 weeks following the surgery in all the cases. The mean neck shaft angle was 125.9 and 24 cases had good results, while 8 cases had fair results by Paavolainen method, at the last follow-up. There were 1 case of delayed union and cerclage wire failure, and 3 cases of subacromial impingement. There were no complications, such as loss of reduction, nonunion, screw loosening, or avascular necrosis of the humeral head. Conclusion: Internal fixation, using a NCB plate, was considered to be an effective surgical method in treating proximal humerus fracture in the elderly patients, on whom the fixation of the fracture and maintenance of reduction are difficult.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.49-54
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• 2002

Purpose : To analyze the clinical results of treatment for the osteochondritis dissecans of femoral condyle by age, the type of lesion and method of treatment. Methods : From March 1991 to February 2000, 17 patients (20 cases) with osteochondritis dissecans of the femoral condyle were followed up over 1 year. Three patients had bilateral lesion. There were 12 cases with trauma history (9 cases with sports injury and 3 cases with direct trauma). The initial symptoms were pain, clicking, locking, giving way in the order of frequency, pain was revealed in all cases. Clinical evaluation of IKDC and Hughston method were used for subjective and objective function. Results : The number of male patient was 12, and the mean age was 19.8 year old (11$\~$50). The location of the lesion was 14 cases in medial femoral condyle and 6 cases in lateral femoral condyle. The arthroscopic findings of the lesion in 15 cases were as follows, early separation in 6 cases, partially detachment in 4 cases, and crators and complete detachment in 5 cases. 5 cases were treated with mutiple drilling and 5 cases with Herbert screw fixation, 3 cases with Herbert screw fixation and bone graft. In early stage, 7 cases were treated with conservative method. In the grading of Hughston score, 6 cases were graded as excellent, 9 cases as good, 15 cases were graded as good to excellent. Based on the IKDC scale, 1 case was graded as normal, 6 as nearly normal, and 10 as abnormal. Conclusions : The trauma seemed to be important factor in occurrence of osteochondritis dissecans of the femoral condyle. The clinical results of juvenile period showed better than adolescence and adult period, it is necessary to detect the lesion as soon as possible. The result of subjective evaluation was worse than the Hughston evaluation. It was caused by limiting involvement of sports activity and limited activity in the adolescence.