Value of Tibiotalocalcaneal Arthrodesis Using Retrograde Intramedullary Nailing in Severe Hindfoot Deformity and Arthritis / 대한정형외과학회잡지

PURPOSE: This study examined the radiological and clinical outcomes of tibiotalocacalcaneal arthrodesis using retrograde intramedullary nailing in a severe hindfoot deformity and ankle/subtalar arthritis. MATERIALS AND METHODS: A total of 22 patients (22 cases) with a severe hindfoot deformity and arthritis underwent tibiotalocalcaneal arthrodesis with retrograde intramedullary nails. The average age was 57.4 years (22–82 years) and the mean follow-up was 29.6 months (12–74 months). The radiological outcomes included an assessment of the preoperative and postoperative coronal ankle alignment, hindfoot alignment, sagittal alignment, and postoperative union time. The clinical outcomes were evaluated using the visual analogue scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) score, and postoperative complications. The results were analyzed statistically by dividing the patients into two groups based on a 10° angle of deformity. RESULTS: Regarding the preoperative coronal ankle alignment, 14 patients had a mean varus deformity of 17.8°±14.5° and six had a mean valgus deformity of 8.1°±6.6°. Postoperatively, a satisfactory postoperative coronal ankle alignment of less than 5° was obtained in all patients. Regarding the preoperative hindfoot alignment, 12 patients showed a mean varus deformity of 15.2°±10.5° and six had a mean valgus deformity of 8.1°±4.2°. In total, 94.4% (17 patients) had satisfactory postoperative hindfoot alignment of less than 5°. Radiological union was achieved in 90.9% at an average of 19.2 weeks (12–32 weeks) and there were 2 cases of nonunion. The clinical outcomes showed improvement in the mean VAS and AOFAS scores (p<0.001, p<0.001, respectively). Even a preoperative severe deformity more than 10° showed a significant deformity correction of coronal ankle alignment and hindfoot alignment, postoperatively (p<0.001, p<0.001, respectively). No significant differences were found between the patients with a preoperative coronal ankle deformity more than 10° and those less than 10° regarding the mean postoperative coronal ankle alignment (p=0.162). CONCLUSION: Tibiotalocalcaneal arthrodesis using retrograde intramedullary nailing is an acceptable technique for achieving satisfactory deformity correction, high union rate with minimal complications, and improvement of the clinical outcomes. In addition, tibiotalocalcaneal arthrodesis using retrograde intramedullary nailing is considered an effective treatment option, particularly in severe ankle and hindfoot deformities.

Diagnosis and Treatment of Occult Lisfranc Injury / 대한족부족관절학회지

PURPOSE: To evaluate the effectiveness of intraoperative stress test for diagnosis of occult Lisfranc injury. MATERIALS AND METHODS: Between April 2009 and October 2012, 21 patients with occult Lisfranc injuries underwent intraoperative stress test and internal fixation. There were 11 males and 10 females with an average age of 45.3 years (range, 23~79 years). Injuries were caused by traffic accident in 10 cases, indirect force (twisting injury) in 8 cases, and crush in 2 cases, falling from a height in 1 case. Unstable injuries on stress radiograph in occult injury of Lisfranc joint were treated by open reduction or closed reduction and fixation with cannulated screw or K-wire. Radiological evaluation was assessed according to preoperative and postoperative diastasis between 1st and 2nd metatarsal base. RESULTS: Assoicated injuries were 9 cases of metatarsal fractures, 6 cases of cuneiform fractures and 6 cases of both metatarsal and cuneiform fractures. Medial and middle column fixation was in 13 cases, and three columns fixation was in 8 cases. Initial diastasis between 1st and 2nd metatarsal base was 2.8 mm (1.3~4.7 mm) on AP radiograph and postoperative diastasis between 1st and 2nd metatarsal base was 1.2 mm (0.5~2.4 mm) on AP radiograph. CONCLUSION: Even there is no sign of clear Lisfranc injury, it is necessary to pay attention and give evaluation on circumstances of occult Lisfranc injuries with metatarsal or cuneiform fractures. Intraoperative stress test is helpful to diagnose an occult Lisfranc injury. For unstable injuries on stress radiographs of occult Lisfranc joint injury, operative treatment with open or closed reduction and internal fixation is useful method.

Surgical Treatment of Achilles Tendon Rupture with Absorbable Suture Materials Only / 대한족부족관절학회지

PURPOSE: To report the clinical results from using absorbable suture materials instead of nonabsorbable materials which have been used more commonly to repair Achilles tendon. MATERIALS AND METHODS: We retrospectively reviewed 21 cases of acute Achilles tendon rupture, treated surgically from 2004 to 2011. Mean follow-up period is 6 months. We repaired Achilles tendon using size 1 Vicryl (Polyglactin 910, Ethicon) for core suture and size 3-0 Vicryl for epitendinous suture. At three months after surgery, we evaluated clinical results with single heel raise height by centimeters, differences of calf circumference and passive range of motion of ankle joint, compared to contralateral side. Also we recorded clinical results with subjective satisfaction grades. RESULTS: At three months after surgery, 20 of 21 patients were able to perform single heel raise over 5 cm in height. Calf circumference differences were less than 1 cm in 12 cases, between 1 cm to 3 cm in 5 cases, more than 3 cm in 4 cases. There was no difference in range of passive motion in 19 cases. All patients satisfied with daily activity except 2 cases with mild discomfort. There was no complication such as rerupture, elongation or infection. CONCLUSION: We experienced excellent clinical results from repairing Achilles tendon with using absorbable suture materials in terms of functional outcomes and patient's satisfaction without any complication. So we may consider using absorbable suture materials instead of nonabsorbable materials to repair Achilles tendon.

Comprehensive Analysis for Risk Factors of Lower Extremity Amputation as a Treatment of Complicated Diabetic Foot / 대한족부족관절학회지

PURPOSE: The diabetic foot lesions are intractable, and aggravation often leads to amputation. None or minor amputation group was treated debridement or toe amputation and major amputation group was treated Ray, Lisfranc, Chopart, Below Knee and Above Knee amputation. We investigate the risk factors for major limb amputations among patients with diabetic foot lesion. MATERIALS AND METHODS: The subjects were 73 diabetic foot lesion patients (83 diabetic foot lesions) treated at our department from January 2006 to December 2010. Non or Minor amputation group of 44 cases were treated with debridement or toe amputation. Major amputation group of 39 cases were treated with Ray, Lisfranc, Chopart, below or above Knee amputation. We investigated socioeconomic factors, diabetes mellitus related factors and wound related factors and laboratory factors. Statistical analysis was done by Students t-test, Chi-square test, Mann-Whitney's U test. RESULTS: In our analysis, wound size, wound classification (Wagner classification, Brodsky classification), white blood cell counts, polymorphoneuclear neutrophil percentage, hemoglobin, C-reactive protein and albumin were risk factors for major amputation (p<0.05). CONCLUSION: Low education level, nutritional condition, premorbid activity level and progressed wound condition were observed in major amputation group compared with non or minor amputation group. In the major amputation group, higher white blood cell count, C-reactive protein level and lower albumin level were observed. Together with maintenance of adequate nutritional condition, early detection of lesions and foot care for early treatment is important. Therefore, active investigation with full risk evaluation of vascular complication is also important.

Does Interfragmentary Cerclage Wire Fixation in Clavicle Shaft Fracture Interfere the Fracture Healing?

PURPOSE: A technique of cerclage wire fixation in comminuted fracture of the clavicle shaft is thought to interfere the fracture healing, so authors studied radiographically and clinically about the cases of cerclage wiring of the fracture fragments with the plate and screws fixation in the comminuted fracture of the shaft of the clavicle. MATERIALS AND METHODS: According to following inclusion criteria, total 18 patients (male: 15, female: 3) were investigated; Patients who visited hospital due to clavicle shaft comminuted fracture from February 2005 to April 2009, who underwent surgery utilizing more than 2 cerclage wire fixation for the fragments when open reduction and plate fixation were operated and who could be follow-up over one year. The duration for fracture union, functional outcome and complications were investigated retrospectively. RESULTS: Radiological bone union was accomplished in average 13.3 weeks (12~16 weeks) and there was no complication such as nonunion, delayed union or infection. Range of motion of ipsilateral shoulder joint was recovered in all patients except one at the final follow-up. CONCLUSION: The clinical and radiographical results of the plate and screws fixation with cerclage wiring of the fragments in comminuted clavicle shaft fracture showed that the cerclage wiring does not interfere the fracture healing, so authors think that this method is a good alternative operation if it is performed carefully to minimize soft tissue dissection.

Pathologic Fracture Due to an Osteoblastoma of the Humerus Shaft: A Case Report / 대한골관절종양학회지

Osteoblastoma is rare, benign, bone-forming tumor that often occur in the spine. There are few reports of osteoblastomas resulting in pathologic fractures involving long bones. Authos report a unique case of a pathologic fracture due to an osteoblastoma of the humerus shaft. The tumor was treated successfully by curettage, intramedullary nailing and bone allograft.

Continuous Half Passive Motion under Distracted External Fixation for the Treatment of Distal Tibial Pilon Fractures / 대한족부족관절학회지

PURPOSE: Pilon fracture has several serious complications such as joint stiffness, arthrosis and delayed angular deformity. We report short-term results of new treatment modality using distracted dynamic external fixators and early controlled ankle motion. MATERIALS AND METHODS: Eight cases of severe pilon fractures for which we tried small plate fixation and additional distracted dynamic external fixators from July 2007 to June 2009 were included. Half passive continuous ankle joint motion was allowed under free hinged ring fixators after the operation. The external fixators were removed after two or three months from the surgery. We investigated joint space by radiograph, joint pain, range of motion, patient's satisfaction of treatment protocol. RESULTS: Joints were distracted when external fixators were applied and mean 28% of space loss developed after removal of external fixators. In most of cases, satisfactory alignments were maintained. Regarding range of joint motion, mean dorsiflexion angle was 15 degrees and mean plantarflexion angle was 32 degree in the condition of wearing external fixators. There was mean 8% reduction of range of motion but no further progression of ankle stiffness after removal of external fixators. Dorsiflexion was not improved after that, but plantarflexion angle was improved 10% even after removal of external fixators. Patients were generally in compliance with the treatment protocols with high level of satisfaction. CONCLUSION: We got good results with distracted dynamic external fixators and early continuous half-passive joint motion for pilon fractures in terms of joint pain and range of motion. Therefore we suggest this new protocol as an alternative modality for severe pilon fractures.

Microtensile bond strength of self-etching and self-adhesive resin cements to dentin and indirect composite resin / 대한치과보존학회지

The purpose of this study was to evaluate the microtensile bond strength (microTBS), failure modes and bonding interfaces of self-etching and three self-adhesive resin cements to dentin and indirect composite resin. Cylindrical composite blocks (Tescera, Bisco Inc.) were luted with resin cements (PA: Panavia F 2.0, Kuraray Medical Inc., RE: RelyX Unicem Clicker, 3M ESPE., MA: Maxem, Kerr Co., BI: BisCem, Bisco Inc.) on the prepared occlusal dentin surfaces of 20 extracted molars. After storage in distilled water for 24 h, 1.0 mm x 1.0 mm composite-dentin beams were prepared. microTBS was tested at a cross-head speed of 0.5 mm/min. Data were analyzed with one-way ANOVA and Tukey's HSD test. Dentin sides of all fractured specimens and interfaces of resin cements-dentin or resin cements-composite were examined at FE-SEM (Field Emission-Scanning Electron Microscope). In conclusion, PA and RE showed higher bond strength and closer adaptation than MA and BI when indirect composite blocks were luted to dentin using a self-etching and three self-adhesive resin cements.

Effect of application methods of a self-etching primer adhesive system on enamel bond strength / 대한치과보존학회지

The purpose of this study was to evaluate the effect of passive or active application of primer and coat times of bond on the shear bond strength when a self-etching primer adhesive (Clearfil SE Bond) was applied to enamel surface. Crowns of sixteen human molars were selected. Buccal and lingual enamels of crowns were partially exposed and slabs of 1.2 mm thick were made. They were divided into one of four equal groups (n = 8). Group 1: passive application of Primer and 1 coat of Bond, Group 2: active application of Primer and 1 coat of Bond, Group 3: passive application of Primer and 2 coats of Bond, Group 4: active application of Primer and 2 coats of Bond. Clearfil AP-X was bonded to enamel suface of each group using Tygon tubes. The bonded specimens were subjected to microshear bond strength (uSBS) testing with a crosshead speed of 1 mm/min. The results of this study were as follows; 1. The uSBS of Group 1 was the lowest among groups and the uSBS of Group 4 was the highest. 2. There was not statistically significant interaction between enamel uSBS by application method of Primer and coat time of Bond (p > 0.05). 3. There was not statistically significant difference between enamel uSBS by passive and active application of Primer (p > 0.05). 4. There was statistically significant difference between enamel uSBS by one- and two-coat of Bond (p < 0.05).

Effect of microleakage of a self-etching primer adhesive according to types of cutting instruments / 대한치과보존학회지

The purpose of this study was to evaluate the effect of burs on microleakage of Class V resin restorations when a self-etching primer adhesive was used. Forty Class V cavities were prepared with four different cutting burs on extracted third molars, and divided into one of four equal groups (n = 10); Group 1-plain cut carbide bur (no. 245), Group 2-cross cut carbide bur (no. 557), Group 3-fine diamond bur (TF-21F), Group 4-standard diamond bur (EX-41). The occlusal and gingival margin of cavities was located in enamel and dentin, respectively. Cavities were treated with Clearfil SE Bond and restored with Clearfil AP-X. Specimens were thermocycled, immersed in a 2% methylene blue solution for 24 hours, and bisected longitudinally. They were observed leakages at enamel and dentinal margins. Data were analyzed using Mann-Whitney and Wilcoxon signed ranked test. The results of this study were as follows; 1. At enamel margin, microleakage of group 4 was statistically higher than those of group 1, 2 and 3 (p < 0.01). 2. At dentinal margin, microleakage of group 4 was statistically higher than group 3 (p < 0.01), but group 1 and 2 were not statistically different with group 3 and 4. 3. Enamel microleakage was statistically higher than dentinal microleakage in group 1, 2 and 3 (p < 0.05), but statistical difference between the microleakage of enamel and dentinal margin was not in group 4. In conclusion, the use of coarse diamond bur showed high microleakage at both enamel and dentinal margin when Clearfil SE Bond was used in class V cavity.

Study for Histopathologic Findings of the Hepatic Artery in the Living Related Liver Transplantation Patients

Living related liver transplantation(LRLT) is theoretically the best treatment option for end stage liver disease and nonresectable hepatocellular carcinomas. Anastomosed hepatic artery is at high risk in thrombosis after LRLT, which directly related to the patient's life. Usually, recipient hepatic artery is so friable and intimal separation and blood clot between intima and media were noted frequently. From December 2001 to June 2003, consecutive 30 hepatic arteries were harvested from 45 LRLTs patients with end stage liver disease. All hepatic artery were anastomosed with #9-0 nylon by plastic surgeon. All hepatic arteries were patent intraoperatively and postoperatively. In the histopathologic study of hepatic artery, some had intimal thickening, myxoid change and intimal hyperplasia in 14 out of 30 cases. Since pathologic changes may develop as a result of transarterial chemoembolization(TACE) and others causes, we postulated that the prevalence of hepatic arterial thrombosis, a catastrophic graft-threatening complication of LRLT, might be increased in this subset of LRLT patients who received TACE. But, in our study, patients who underwent hepatic arterial chemoembolization statistically do not show an increased risk of developing hepatic arterial thrombosis or other hepatic arterial complications after LRLT. And pathologic changes are statistically not correlate with the TACE.

The Effect of Plasma Treatment of Poly (Lactic-co-Glycolic)(PLGA) Scaffold on Adhesion and Bioactivity of Cultured Chondrocytes

The advantages of wielding synthetic polymer are that the pore size, physical strength and chemical composition can be easily controlled. However, the synthetic polymer has hydrophobic character and low affinity to cells and other bio molecules. This study was performed to investigate the effect of plasma glow's discharge on the surface modification of poly(lactic-co-glycolic acid)(PLGA) sponge on the adhesion and bio-activity of chondrocytes in vitro culture. PLGA sponges(lactic acid: glycolic acid = 85 : 15, pore size=200 - 300 mrcro m, dimension=15 x 2 mm) were prepared. The experimental group(n=8) was treated with a radiofrequency plasma glow-discharge(acrylic acid and oxygen: 50 W, 0.2 torr for 30 seconds) but the control group (n=8) was treated with nothing. 1 x 10(6)ml/20 microliter of P3 chondrocytes from rabbit ears were used for seeding. Eight hours after cell seeding, the total DNA amount of chondrocytes attached to the PLGA and the changes of actin were evaluated under a confocal microscope. Type I and II collagen expression were detected by RT-PCR three weeks after seeding for an evaluation of phenotypic maintenance. The total DNA amount of attached chondrocytes was remarkably increased in the experimental group(p < 0.05). After scrutinizing with a confocal microscope, the actin of cells was more spread out and finely arranged in the experimental group than in the control group. Both types of collagen expression were significantly increased in their assigned groups. Plasma treatment of the PLGA sponge could increase the adhesion property of chondrocytes, and provide suitable environment for maintaining the phenotype of chondrocytes.

Cause of Enterohemorrhagic Escherichia coli Infection in Ulju County, Korea / 예방의학회지

OBJECTIVES: Two related cases of Hemolytic-Uremic Syndrome (HUS) were reported to the Korea National Institute of Health in May, 2001. Shiga toxin 2 genes were detected in both stool samples. We suspected an enterohemorrhagic Escherichia coli (EHEC) infection as the cause of the HUS, and conducted an investigation to find the source of the infection and its route of transmission. METHODS: We performed case investigations on these two related HUS cases, and obtained interviews and rectal swabs form the family members and other close contacts. Additionally, we performed rectal swabs on the cattle raised by the household of the index patient. RESULTS: We found a 20 month old index patient and a 6 year-old cousin had developed HUS, where there had been a 2 day history of contact with the index, and bacteriological examinations for these two patients revealed, indistinguishably, the same E. coli O171. The grandmother of the index patient was found to be asymptomatic, but E. coli O26 was isolated. We also found a probable case in the mother of the cousin. She reported a history of contact with the index, and developed bloody diarrhea of 3 days duration. The test results for the cattle revealed E. coli O26 in one cow, and E. coli O26 and O55 in another. E. coli O26, which was isolated in both cows and the grandmother of the index, were indistinguishably the same. CONCLUSIONS: We found that the E. coli O26 in the grandmother had originated from the cows, and that the E. coli O171 found in the index patient had been transmitted to the cousin through person-to-person contact.

Absorption Rates of Various-thickness Human Acellular Dermal Grafts(SureDerm(R))

The human acellular dermal graft provides safe and lasting volume gain for soft tissue augmentation in the face. However, variable amounts of the graft are gradually reabsorbed in the host tissue. The purpose of this experiment is to evaluate the absorption rates of the implanted acellular dermal grafts (SureDerm(R)) and to estimate the amount of overcorrection in the soft tissue augmentation. Twenty-eight New Zealand white rabbits were divided into 4 groups. A 2.0x 2.5 cm sized subcutaneous pocket was created on the dorsal surface of the ear. 10x10 mm sized SureDerm(R) sheets, each 1 mm, 2 mm, 3 mm and 4 mm in thickness were implanted into the pockets. Ear thickness was measured by Thickness Gauze at the time of pre-operative, immediate post-operative, 4, 8 and 12 weeks after implantation. Full thickness ear was harvested in 4, 8 and 12 weeks and examined histologically for graft thickness, host tissue ingrowth, neocollagen synthesis and inflammatory reaction. Ear thickness was mildly increased due to swelling and inflammatory reaction in the initial 4 weeks in all groups and then was decreased in 12 weeks by 84%. However, there was a significant decrease in the thickness of the graft itself (43%). There was no significant difference in the ear thickness among the groups (p<0.05) with time. Histological analysis of implanted SureDerm(R) sheets demonstrated progressive neovascularization, fibroblast infilteration, neocollagen bundle synthesis and organization. Our experimental study suggests that the absorption rate of SureDerm(R) is quite uniform regardless of the thickness of the graft. The amount of overcorrection is relatively predictable and 18% of overcorrection seems to be needed for satisfactory result.

Culture of Chondrocytes on Scaffolds with Different Pore Network of PLGA and PLLA

This study was performed to investigate the in vitro proliferation and migration of rabbit auricular chondrocytes into the various sized pore of PLLA and PLGA scaffolds. The chondrocytes were harvested, expanded, and seeded onto PLGA(50 : 50, 75 : 25, 85 : 15) and PLLA scaffold having either small(50 - 100 micrometer) or large(300 - 350 micrometer) pores. On the 4th and 8th week after culture, histologic observation and quantitative DNA assay were done. We noted that the largest amount of DNA was found in the 85 : 15 PLGA sponges than others, and in the 4th and 8th week, some amount of DNA was detected in the lower portion of 85 : 15 PLGA sponge only, and DNA amounts were increased during the culture period in the 85 : 15 PLGA, significantly. We also found that the numbers of cells were low in middle portion of scaffolds, and in large pore-sized group of 85 : 15 PLGA, there were many cells in the lower portion of the scaffolds more than that of small pore group. In conclusion, the pore size of the scaffold for chondrocyte culture is important for cell migration and proliferation, and PLGA, especially 85 : 15 PLGA with 300- 350 micrometer sized pore is the more suitable biomatrix for proliferation and migration of the chondrocytes.

Early Development of Microvascular Surgery in Korea: To the Memory of the Late Dr. Poong Lim

Microvascular surgery in Korea started in 1970's. Doctor Poong Lim was one of several dedicated surgeons who made great efforts to develop this field in Korea. By performing inguinal free flap in 1978, he became the first man who applied microvascular surgical technique to the clinical field in Korea. In addition, he played an important role in the settlement of microvascular surgery in Korea, performing variety of free flaps such as omental free flap, dorsalis pedis free flap, and deltopectoral free flap in 1979. He also introduced microvascular surgery to the traumatic field by successfully performing multiple finger replantation and forearm replantation in 1979. Both his clinical and experimental works made it possible for microvascular surgery to become an important part of plastic surgery in Korea.

In Vivo Biodegradability of PLLA and PLGA Sponge using Non-toxic Effevescent as a Porogen Additive

In many tissue engineering application, highly open porous scaffolds are required for efficient cell seeding and culture. Synthetic biodegradable polymers such as poly (L-lactic acid)(PLLA) and its copolymers with D-lactic and glycolic acids(PLGA) are widely used as a porous scaffold. The suitable biodegradability and dimensional stability of porous scaffolds during in vivo implantation play an important role in tissue engineering application. In this study, we investigated in vivo biodegradation and dimensional stability of acellular porous polymer scaffolds prepared by using a gas foaming technique with non-toxic effervescent mixture. In addition, we have engineered cartilage tissue 3D cultured on PLGA scaffolds in nude mouse in order to compare with degradation and deformation on acellular porous polymer scaffolds and to form tissue-engineered cartilage tissue. Sodium bicarbonate and citric acid crystals were used as an effervescent mixture. These particles were milled and sieved to yield various range of sizes(50 - 100, 100 - 300, and > 300 micrometer). After polymer scaffolds fabricated, biodegradation test was performed in subcutaneous tissue of male rats during 12 weeks. Degradability of polymer scaffolds were evaluated by weight difference, gel permeation chromatography(GPC), and SEM as each period. Tissue-engineered cartilage by transplanting 3D cultured chondrocytes onto PLGA 85:15 scaffolds in nude mouse was also made and compared with acellular scaffolds. In conclusion, highly open porous biodegradable scaffolds are prepared by gas foaming method using sodium bicarbonate and citric acid as a non-toxic effervescent mixture. Furthermore, tissue-engineered cartilage formation by in vivo 3D culture onto modified PLGA scaffolds in nude mouse was significantly improved as compared to controls.

An Adhesion of Cartilage to Silicone Block using Histoacryl Glue

Plastic surgeons have been in pursuit of natural appearance in rhinoplasty, which means harmonious relationship between nasal tip and dorsum. If silicone implant is used alone for the augmentation of the nasal tip, there is a possibility of the thinning of the nasal tip skin and exposure of implant. For these reasons, plastic surgeons have used a cartilage fixation over the silicone implant for nasal tip augmentation. However, fixation by sutures is technically challenging, so authors tried to use Histoacryl glue instead of sutures. Twelve New Zealand white rabbits were used in this study. Four 5mm diameter and 1mm thick cartilages were harvested from ear. Two cartilages were fixed to the silicone blocks by chromic catgut and the others were attached by Histoacryl glue. Four cartilage-silicone complexes were implanted into the subcutaneous pocket of the rabbit's head. In the 1st, 3rd and 5th week, the cartilage- silicone complexes were harvested and the shearing forces between cartilages and silicones were measured by texture analysis. The shearing forces were not changed in the Histoacryl group with the lapse of time but decreased in the suture group. However, the difference between the 2 groups were not statistically significant. The histologic findings of both groups showed progressive fibrosis. This study showed the possibility of using Histoacryl glue as a simple method of fixing cartilage to the silicone.

In Vivo Implantation of Chondrocytes Seeded into a Three-dimensional PLGA Sponge: Is in Vitro Culture before Implantation Necessary?

For tissue-engineered neocartilage formation in vivo, most studies have cultured chondrocytes within a biodegradable polymer in vitro before implantation of cell-polymer complex into an animal. The present study was performed to investigate the necessity of in vitro culture (preconditioning). Cell-polymer complex was made of chondrocytes obtained from a rabbit ear and a 85:15 poly(DL-lactic-co- glycolic acid) (PLGA) sponge. The complex was implanted into a nude mouse either after or without in vitro preconditioning. For control groups, PLGA sponge without chondrocytes was used. One, 2, and 4 weeks after the implantation, each group was examined by measurement of weight and volume of sponges as well as histologic study with Safranin-O staining. The control groups showed loss of weight as time passed. The non-preconditioned group, on the other hand, showed weight loss for the first week, but increased in weight afterwards. The preconditioned group also had weight loss in the first week after the implantation with no noticeable weight changes thereafter. Neither weight nor volume of PLGA sponges in preconditioned group was significantly different from those in non-preconditioned group until the 2nd week. In the 4th week, volume of sponges in non-preconditioned group was significantly larger than that in preconditioned group. On histological observation, chondrocytes seeded into a PLGA sponges proliferated and differentiated into cartilage tissues both in preconditioned and non-preconditioned groups, but non-preconditioned group formed cartilage tissue more extensively than the preconditioned group. Based on the above results, it is suggested that new cartilage tissues can be formed successfully following the implantation of cell- polymer complex into a living body without any prior conditioning in a separate culture system.

Advantage of a New Epineural Nerve Repair Technique: Oblique Coaptation

In 1999 Kayikcioglu and his colleagues invented the oblique nerve coaptation technique which increases coaptation surface and proved that their technique is superior to conventional vertical coaptation technique. This method is useful but it is not fit for a clinical application because the sciatic nerve was cut obliquely and repaired immediately in their experiment. In that case, we couldn't exclude the possibility of the improved effect by increased orientation of nerve fiber. Using different nerves we could exclude the effect by orientation improvement and prove the superiority of the oblique nerve coaptation technique in functional restoration. Ten Sprague-Dawley rats were used. The tibial nerve and the peroneal nerve were cut randomly to 30 degree and 90 degree on each side. The distal stump of the tibial nerve and the proximal stump of the peroneal nerve were repaired with 10-0 nylon under microscopic view. 12 weeks after nerve coaptation, nerve conduction velocity of extensor digitorum longus muscle, moist weight and histological analysis of extensor digitorum longus muscle, and myelinated axonal count and histological analysis of peroneal nerve were investigated. The results showed the nerves of oblique coaptation(30 degree transection angle) group are more regenerated than those of vertical coaptation(90 degree transection angle) group and nerve conduction velocity and moist weight of extensor digitorum longus muscle are also increased in oblique coaptation group. From these results we came to a conclusion that the oblique nerve coaptation technique is superior to the conventional technique and may be helpful in innervated free flap or nerve graft.