• Journal of Korean Neurosurgical Society
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• 제61권1호
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• pp.114-119
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• 2018

Objective : The purpose of this study was to determine the feasibility of screw fixation in previously augmented vertebrae with bone cement. We also investigated the influence of cement distribution pattern on the surgical technique. Methods : Fourteen patients who required screw fixation at the level of the previous percutaneous vertebroplasty or balloon kyphoplasty were enrolled in this study. The indications for screw fixation in the previously augmented vertebrae with bone cement included delayed complications, such as cement dislodgement, cement leakage with neurologic deficits, and various degenerative spinal diseases, such as spondylolisthesis or foraminal stenosis. Clinical outcomes, including pain scale scores, cement distribution pattern, and procedure-related complications were assessed. Results : Three patients underwent posterior screw fixation in previously cemented vertebrae due to cement dislodgement or progressive kyphosis. Three patients required posterior screw fixation for cement leakage or displacement of fracture fragments with neurologic deficits. Eight patients underwent posterior screw fixation due to various degenerative spinal diseases. It was possible to insert screws in the previously augmented vertebrae regardless of the cement distribution pattern; however, screw insertion was more difficult and changed directions in the patients with cemented vertebrae exhibiting a solid pattern rather than a trabecular pattern. All patients showed significant improvements in pain compared with the preoperative levels, and no patient experienced neurologic deterioration as seen at the final follow-up. Conclusion : For patients with vertebrae previously augmented with bone cement, posterior screw fixation is not a contraindication, but is a feasible option.

• Archives of Plastic Surgery
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• 제33권6호
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• pp.688-694
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• 2006

Purpose: Reconstruction of the craniofacial defects can be carried out with autogenous tissues, allogenic implants, or alloplastic materials. Titanium mesh systems have been used for bony reconstruction in non load-bearing areas. They offer several advantages: immediate availibility without any donor site morbidity, easy handling, stable 3-D reconstruction, and low susceptibility to infection. The aim of this study is to evaluate the usefulness and complications of titanium mesh system in the reconstruction of the craniofacial defects. Methods: From Jan. 2000, to Dec. 2004, we performed reconstruction of craniofacial bone defects in 21 patients who had benign or malignant tumor and fracture events in the cranium, orbit, nasal bone, maxilla, zygoma and the mandible. The size of the defects ranged from $1.0{\times}1.5cm$ to $12{\times}10cm$. Two different mesh systems, micro-titanium augmentation mesh and dynamic mesh was used for bony reconstruction in non load-bearing areas. The patients were evaluated from 1 to 4 yrs clinically and radiographically with a mean follow up period of 1.5 yrs. Results: There were no serious complications, including wound infection, foreign body reaction, exposures or loos of the mesh, central infection and pathologic findings of bone around mesh exception of one patient, who had expired of skull base tumor recurrence. Long-term stability of the reconstructions and the overall functional and aesthetic outcome was excellent. Conclusion: Our experiences demonstrate that the Titanium mesh system is a relatively safe and efficient method in the craniofacial reconstruction and have broadens our choices of therapeutic procedures in the craniomaxillofacial surgery.

• Advances in biomechanics and applications
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• 제1권3호
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• pp.187-210
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• 2014

With the goal of increasing the survivorship of the prosthesis and anticipating primary stability problems of new prosthetic implants, finite element evaluation of the micromotion, at an early stage of the development, is mandatory. This allows assessing and optimizing different designs without manufacturing prostheses. This study aimed at investigating, using finite element analysis (FEA), the difference in the prediction of the primary stability of cementless hip prostheses implanted into a $Sawbones^{(R)}$ 4th generation, using the manufacturer's mechanical properties and using mechanical properties close to that of human bone provided by the literature (39 papers). FEA was carried out on the composite $Sawbones^{(R)}$ implanted with a straight taper femoral stem subjected to a loading condition simulating normal walking. Our results show that micromotion increases with a reduction of the bone material properties and decreases with the augmentation of the bone material properties at the stem-bone interface. Indeed, a decrease of the cancellous Young modulus from 155MPa to 50MPa increased the average micromotion from $29{\mu}m$ up to $41{\mu}m$ (+42%), whereas an increase of the cancellous Young modulus from 155MPa to 1000MPa decreased the average micromotion from $29{\mu}m$ to $5{\mu}m$ (-83%). A decrease of cortical Young modulus from 16.7GPa to 9GPa increase the average global micromotion from $29{\mu}m$ to $35{\mu}m$ (+33%), whereas an increase of the cortical Young modulus from 16.7GPa to 21GPa decreased the average global micromotion from $29{\mu}m$ to $27{\mu}m$ (-7%). It can also be seen that the material properties of the cancellous structure had a greater influence on the micromotion than the material properties of the cortical structure. The present study shows that micromotion predicted at the stem-bone interface with material properties of the $Sawbones^{(R)}$ 4th generation is close to that predicted with mechanical properties of human femur.

• Journal of Periodontal and Implant Science
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• 제39권sup2호
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• pp.205-212
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• 2009

Purpose: The aim of this retrospective study was to compare the survival rate of oxidized titanium implants and sandblasted large-grit acid etched implants in soft bone. Methods: 201 oxidized titanium implants were inserted in 84 patients between May 1999 and May 2004. 120 sandblasted large-grit acid etched implants were inserted in 74 patients between December 2000 and May 2004. The patients were followed-up 0${\sim}$5 years in ITI group or 0${\sim}$6 years in BRA group, respectively. The following information was collected from the patient records: age, gender, systemic disease, implant type, number, length and diameter of the implants, their location in the jaws, bone quantity, the number of failed implants, the causes of failure, and advanced surgery for bone augmentation. Results: In the oxidized titanium implants, 8 implants showed early failure, and 1 implant showed late failure, respectively. The cumulative survival rate was 95.48%. In the sandblasted large-grit acid etched implants, 1 implant showed late failure and cumulative survival rate was 99.10%. The cumulative survival rate and the survival rates in the case of the advanced procedure during the implant placement were not significantly different in both groups. Conclusions: Oxidized titanium implants and sandblasted large-grit acid etched implants can be used successfully in soft bone regardless of the surgical methods used during the implant placement. (J Korean Acad Periodontol 2009;39:205-212)

• Journal of Periodontal and Implant Science
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• 제43권2호
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• pp.64-71
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• 2013

Purpose: The objective of this study was to elucidate the role of collagen membranes (CMs) when used in conjunction with bovine hydroxyapatite particles incorporated with collagen matrix (BHC) for lateral onlay grafts in dogs. Methods: The first, second, and third premolars in the right maxilla of mongrel dogs (n=5) were extracted. After 2 months of healing, two BHC blocks ($4mm{\times}4mm{\times}5mm$) were placed on the buccal ridge, one with and one without the coverage by a CM. The animals were sacrificed after 8 weeks for histometric analysis. Results: The collagen network of the membranes remained and served as a barrier. The quantity and quality of bone regeneration were all significantly greater in the membrane group than in the no-membrane group (P<0.05). Conclusions: The use of barrier membranes in lateral onlay grafts leads to superior new bone formation and bone quality compared with bone graft alone.

• Journal of Periodontal and Implant Science
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• 제52권4호
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• pp.325-337
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• 2022

Purpose: The aim of this study was to investigate the effect of (1) the size of the bony access window and (2) collagen membrane coverage over the window in sinus floor elevation in a rabbit sinus model. Methods: Small bony access windows (SW; ø 2.8 mm) were made in 6 rabbits and large windows (LW; ø 6 mm) in 6 other rabbits. Both sinuses in each rabbit were allocated to groups with or without coverage of a collagen membrane (CM) on the window, resulting in 4 groups: SW, LW, SW+CM, and LW+CM. After 4 weeks of healing, micro-computed tomographic, histologic, and histomorphometric analyses were performed. Results: Bony healing in the window area was incomplete in all groups, but most bone graft particles were well confined in the augmented cavity. Histologically, the pattern of new bone formation was similar in all groups. Histomorphometrically, the percentage of newly formed bone was greater in the groups with CM than in the groups without CM, and in the groups with SW than in the groups with LW (12.92%±6.40% in the SW+CM group, 4.21%±7.73% in the SW group, 10.45%±4.81% in the LW+CM group, 11.77%±3.83% in the LW group). The above differences were not statistically significant (P>0.05). Conclusions: The combination of a small bony access window and the use of a collagen membrane over the window favored new bone formation compared to other groups, but this result should be further investigated due to the limitations of the present animal model.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권2호
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• pp.238-242
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• 2000

Recurrent mandibular dislocation is frequent morbidity of temporomandibular joint relatively. There are many etiologic causes in TMJ disorders but, difficult to find obvious one. Various treatment methods have been utilized for a mandibular dislocation. It is categorized into two groups broadly - nonsurgical or surgical methods. The basic rationale of the surgical method is to allow free movement of the condyle by reducing height of articular eminence or to limit anterior excessive movement of the condyle by increasing height of articular eminence or soft tissue anchoring procedure. In this case, 69 year-old woman was treated by augmentation of the articular eminence with mandibular symphysial bone graft leading to osteosynthesis without difficulty. As a result, favorable postoperative outcome was obtained functionally without any complication or recurrence.

• 대한두개안면성형외과학회지
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• 제12권1호
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• pp.43-47
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• 2011

Purpose: Romberg's disease manifests as progressive hemifacial atrophy of the skin, soft tissue and bone, which usually begins in the first or second decade of life. When present, atrophy may originate from the cutaneous stigmata and may become so sharply delimited by the midline. Methods: A 10-year-old girl, who had suffered from right mandibular area atrophy for 3 years, visited us and was diagnosed with Romberg's disease. The depressed lesion of the face was augmented successfully using a deepithelialized groin free flap. The superficial circumflex iliac vessels were used as the donor pedicle and the facial artery and vein were used as the recipient vessels. Results: After surgery, the flap survived well and she was satisfied with the result. Although there are various methods of facial augmentation using free flaps, this flap has some advantages. First, there is a considerable amount of fat tissue components for augmentation. Second, flap elevation with thinning is possible. Third, the donor site can be hidden. Conclusion: The groin dermo-fat free flap is a good method for the facial augmentation of Romberg's disease.

• 대한의용생체공학회:의공학회지
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• 제24권5호
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• pp.401-410
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• 2003

본 연구에서는 유한요소법을 이용하여 대퇴골 전자간 골절 치료에 대한 다양한 수술기법을 골밀도 변화에 따라 생체역학적으로 분석하여 이를 평가하고자 한다. 이에 구현된 모델들은 압박 고관절 나사만을 이용하여 시술한 모델 (Type I), 삽입된 압박 고관절 나사 주위에 시멘트 영역을 확보한 뒤 골 시멘트로 보강하는 시술을 구현한 모델 (Type II),대학교추가의 골소실이 없이 시멘트를 가압하여 주입하는 시술을 구현한 모델 (TypeIII)의 3가지 형태로 구현하였다. 시술 상황에 따라 골절부위와 삽입물의 경계면 주위에 접촉요소를 사용하기 위해 적절한 마찰계수를 설정하였으며, 골다공증 정도 (Singh Indices, II∼V)에 따라 대퇴골의 물성치를 적절하게 적용시켰다. 각 모델에 있어 골밀도 변화에 따른 수술기법의 차이를 분석하기 위하여 다음과 같은 인자를 분석하였다 : (a) 대퇴골두 내에서의 von Mises 응력 부피비, (b) 대퇴골두 망상골과 인공 삽입물내에서의 최대 von Mises 응력 (PVMS), (c) 대퇴골두 내에서의 최대 von Mises 변형률 (MVMS), (d) 골절 부위와 인공 삽입물 주위에서의 미세운동량. 수술기법 중 Type III가 대퇴골두 내에서 골밀도 변화에 상관없이 가장 낮은 PVMS, MVMS 수치를 보여 가장 효율적인 결과를 나타내었다. 이는 기존 시술법 (Type I,II)에 비해 내고정 실패 가능성이 가장 적을 것으로 예측되었다. 특히, 골밀도가 낮을 때에는 Type III의 수술 효과가 더욱 커지는 것으로 나타났다. 또한, 삽입물 주위에서 미세운동량을 분석한 결과, Type III의 수치가 다른 시술법들의 15∼20%로 나타나 시멘트를 가 압하여 보강하는 시술법이 삽입물 주위의 미세운동을 억제하는데 있어 가장 효과적이다는 것을 증명하는 것이다. 이러한 결과로부터, 압박 고관절 나사를 이용한 대퇴골두 전자간 골절 치료에 있어 골 시멘트를 가압하여 보강하는 방법이 골밀도가 낮은 환자에 있어 인공삽입물의 내고정 및 골유합에 가장 큰 효과를 보일 것으로 사료된다.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.273-288
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• 2006

The purpose of this study was to evaluate exophytically vertical bone formation in rabbit calvaria by the concept of guided bone regeneration with a custom-made porous titanium membrane combined with bone graft materials. For this purpose, a total of 12 rabbits were used, and decorticated calvaria were created with round carbide bur to promote bleeding and blood clot formation in the wound area. Porous titanium membranes (0.5 mm in pore diameter, 10 mm in one side, 2 mm in inner height) were placed on the decorticated calvaria, fixed with metal pins and covered with full-thickness flap. Experimental group I was treated as titanium membrane only. Experimental group II, III, IV was treated as titanium membrane with BBM, titanium membrane with DFDB and titanium membrane with FDB. The animals were sacrificed at 8 and 12 weeks after surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. 1. Porous titanium membrane was biocompatable and capable of maintaining the regeneration space. 2. At 8 and 12 weeks, all groups demonstrated exophytic bone formation and there was a statistical significant difference among different groups only at 12 weeks. 3. The DFDB group revealed the most new bone formation compared to other groups (p<0.05). 4. At 12 weeks, DFDB and FDB groups showed the most significant resorption of graft materials (p<0.05). 5. The BBM was not resorbed at all until 12 weeks. 6. The fixation metal pin revealed excellent effect in peripheral sealing. On the basis of these findings, we conclude that a porous titanium membrane may be used as an augmentation membrane for guided bone regeneration, and DFDB as an effective bone forming graft material. The fixation of the membrane with pin will be helpful in GBR technique. However, further study is required to examine their efficacy in the intraoral experiments.