Adequate Serial Monolayer Passage Number of Human Intervertebral Disc Cells for Cell Therapy: Growth and Phenotype of Cells

STUDY DESIGN: This is an in-vitro experimental study. OBJECTIVES: We wanted to analyze the changes in the growth and phenotype of human degenerative intervertebral disc cells depending on the frequency of subculture in an in vitro monolayer culture system. SUMMARY OF THE LITERATURE REVIEW: A subculture of disc cells is needed to obtain an adequate amount of disc cells for cell therapy, tissue engineering and analysis of the biological characteristics of degenerative disc cells. MATERIALS AND METHODS: The obtained intervertebral discs were divided into the nucleus pulposus (NP) and the annulus fibrosus (AF). The AF and NP cells were cultured in a monolayer manner, respectively. At each subculture time, we analyzed the morphological changes, the adhesion rate, the proliferation rate and the viability. The expressions of types I and II collagen and proteoglycan were analyzed at the mRNA gene level. RESULTS: Both the AF and NP cells gradually showed a fibroblast-like spindle shape while undergoing subculture. The adhesion rate was higher at the second and third times of subculture. The cell proliferation was the highest at the second subculture time. The viability was markedly lower prior to the subculture. On RT-PCR, the type II collagen expression was gradually decreased in the NP cells. In the AF cells, Type II collagen was not expressed from the second time of subculture. The expression of proteoglycan was gradually decreased in both. CONCLUSIONS: Following the 3rd subculture, the degenerative disc cells had completely changed their original growth and phenotypic characteristics. Therefore, we believe that it is not desirable for us to do passage cultures more than three times for cell therapy.

Accelerated L5-S1 Segment Degeneration after Spinal Fusion on and above L4-5 : Minimum 4-Year Follow-Up Results

OBJECTIVE: Many biomechanical and clinical studies on adjacent segment degeneration (ASD) have addressed cranial segment. No study has been conducted on caudal segment degeneration after upper segment multiple lumbar fusions. This is a retrospective investigation of the L5-S1 segment after spinal fusion at and above L4-5, which was undertaken to analyze the rate of caudal ASD at L5-S1 after spinal fusion on and above L4-5 and to determine that factors that might have influenced it. METHODS: The authors included 67 patients with L4-5, L3-5, or L2-5 posterior fusions. Among these patients, 28 underwent L4-5 fusion, 23 L3-5, and 16 L2-5 fusions. Pre- and postoperative radiographs were analyzed to assess degenerative changes at L5-S1. Also, clinical results after fusion surgery were analyzed. RESULTS: Among the 67 patients, 3 had pseudoarthrosis, and 35 had no evidence of ASD, cranially and caudally. Thirteen patients (19.4%) showed caudal ASD, 23 (34.3%) cranial ASD, and 4 (6.0%) both cranial and caudal ASD. Correlation analysis for caudal ASD at L5-S1 showed that pre-existing L5-S1 degeneration was most strongly correlated. In addition, numbers of fusion segments and age were also found to be correlated. Clinical outcome was not correlated with caudal ASD at L5-S1. CONCLUSION: If caudal and cranial ASD are considered, the overall occurrence rate of ASD increases to 50%. The incidence rate of caudal ASD at L5-S1 was significantly lower than that of cranial ASD. Furthermore, the occurrence of caudal ASD was found to be significantly correlated with pre-existing disc degeneration.

Degenerative Changes of Adjacent Segment after Anterior Cervical Discectomy and Fusion / 대한척추외과학회지

STUDY DESIGN: A retrospective radiologic analysis of 34 patients OBJECTIVES: To evaluate the factors influencing the radiographic degenerative changes in the adjacent segments in one-level ACDF SUMMARY OF LITERATURE REVIEW: There is a 25% incidence of adjacent segment degeneration after 5 years. MATERIALS AND METHOD: From 2002 to 2005, 34 patients (male 23, female 11) underwent anterior cervical spine fusion using a cage or bone block for degenerative cervical spine. The mean age of the patients was 51 years and the mean follow-up period was 24 months. The degenerative findings of the upper and lower adjacent segment were measured from the pre-operative MRI. The fused segment curvature, disc heights of the adjacent segments, displacement of the vertebral bodies and angular mobility in the adjacent segments were measured from the pre-operative and final follow-up lateral views in the neutral position, in both flexion and extension. RESULTS: Degenerative changes in the adjacent segments were observed in 19 of the 34 patients. The group with degenerative changes showed significantly more lordotic angular loss of the fusion segments (11.9+/-3.1degrees) at the follow-up observation than the group with no degenerative changes (9.0+/-1.1degrees) (p=0.04). The group with degenerative change showed a significantly larger increase in disc height of the fusion segments (2.8+/-0.2 mm) at the follow-up observation than the group with no degenerative changes (2.2+/-0.3 mm) (p=0.02).The group with a Grade IV or higher level of pre-operative disc degeneration showed more degenerative changes in the adjacent segments than those with Grade III or lower. CONCLUSIONS: It is important to preserve the lordotic angle of fused segments and avoid excessive increases in disc height. The recurrence of the neurological is not associated with the preoperative adjacent segmental degenerative changes in ACDF.

Degenerative Change of Femoral Head Cartilage in the Elderly with Hip Fracture / 대한정형외과학회잡지

PURPOSE: To evaluate the incidence, grade and extent of the degenerative changes in the femoral head articular cartilage in the elderly with hip fracture through gross, histological and immunohistochemical studies. MATERIALS AND METHODS: The study examined 30 femoral heads obtained from patients over 65 years with no arthrosis by radiograph, who had undertaken bipolar hemiarthroplasty due to hip fracture. The mean age of patients was 79.7 years and the study examined three weight bearing zones (anterior, middle and posterior) and one non-weight bearing zone (inferior) of each femoral head. RESULTS: The gross findings showed significant correlation with the Mankin grade for each zone (p<0.05). Twenty four cases (80%) showed mild degeneration according to the Mankin grade and the others moderate. The mean Mankin score at each zone of all femoral heads was 5 points, which indicated mild degeneration. No significant difference was found between the weight bearing zone and the non-weight bearing zone (p=0.75). The distribution of type II collagen antibody stainabilities mainly showed normal or mild degeneration (93.3%). CONCLUSION: Degeneration of the articular cartilage of the femoral heads in the elderly with hip fracture and no arthrosis by radiograph was mostly mild, and showed generalized changes regardless of the zone.

Degenerative Change of Adjacent Segments according to the Fusion Method after L4-5 Segmental Fusion: Comparative Study of Posterolateral Fusion and Posterior Lumbar Interbody Fusion / 대한정형외과학회잡지

PURPOSE: We wanted to investigate the difference in the incidence of post-fusion adjacent segment degeneration between performing posterolateral fusion and posterior lumbar interbody fusion. MATERIALS AND METHODS: One hundred fifty seven patients who underwent L4-5 fusion using pedicle screws for degenerative lumbar disease and followed up more than three years were analyzed retrospectively. Eighty-six cases of posterolateral fusion (group I) and 71 cases of posterior lumbar interbody fusion (group II) were compared. Sampling bias was evaluated by comparing gender, age, the preoperative degeneration of adjacent segments, the sagittal angle of fusion segments on the last follow up and the follow-up period. The differences of adjacent segments degeneration and the revision rate between the two groups were investigated multilaterally. The actual risk factors for such degeneration were investigated by performing multiple logistic regression test, which contrasted the degeneration group with the non-degeneration group for all the above factors, including whether interbody fusion was done or not. RESULTS: Sampling bias was excluded except for the preoperative proximal adjacent segments degeneration (p=0.036). There was no statistical difference in the final proximal degeneration (31/86, 36% in group I, 26/71, 37% in group II, p=0.536) and revision (8/86, 9% in group I, 6/71, 8% in group II, p=0.536). There was no statistical difference in the final distal degeneration (9/86, 10% in group I, 8/71, 11% in group II, p=0.536) and revision (4/86, 5% in group I, 2/71, 3% in group II, p=0.435). When comparing those cases who developed degeneration on either side with the non-degeneration cases, the odds ratio of old age and an insufficient sagittal angle of the fusion segments reached statistical significance (p=0.024, 0.001). CONCLUSION: There were no differences in adjacent segments degeneration between the posterolateral fusion group and the posterior lumbar interbody fusion group. Rather than the operation methods, old age and insufficient sagittal angle of the fusion segments were the actual risk factors of such degeneration.

Degenerative Changes of Adjacent Segment Following Cervical Anterior fusion: Correlation with Preoperative MRI Findings of Adjacent Disc / 대한척추외과학회지

STUDY DESIGN: We retrospectively reviewed the preoperative and postoperative radiographs of patients who underwent anterior cervical discectomy and fusion. OBJECTIVES: We wanted to determine whether the preoperative Magnetic Resonance Imaging (MRI) findings of the levels adjacent to the level of fusion correlated with the postoperative degenerative changes seen on X-ray after anterior cervical discectomy and fusion. SUMMARY OF LITERATURE REVIEW: Anterior cervical fusion causes acceleration of the degenerative changes at the levels below or above the fused segment. These changes may be accelerated if preoperative MRI shows degenerative changes at the levels adjacent to the segment to be fused. MATERIALS AND METHODS: Twenty-two patients (forty-four adjacent levels) who underwent anterior cervical discectomy and fusion from January 1998 to August 2002 (average follow up: 2 years and 6 months, range: 2 to 4 years) were enrolled in this study. Preoperatively, all the patients had no degenerative changes at adjacent levels on the plain radiographs, but they had at least one adjacent level with degenerative findings on MRI. The patients were grouped according to the findings of the adjacent levels seen on MRI: low signal changes on the T2 weighted image (group A), disc bulging on the sagittal and axial images (group B), annular tear seen on the axial image (group C), osteophyte formation (group D), and no abnormalities (group E). RESULTS: Out of 44 cases of 22 patients, 14 cases (31.8%) showed degenerative changes. 2 out of 7 in group A, 6 out of 11 in group B, 3 out of 4 in group C, 2 out of 3 in group D and 1 out of 19 in group E showed degenerative changes on X-rays at the final follow up. CONCLUSION: Our findings suggest that abnormalities on the levels adjacent to the level to be fused, as seen on preoperative MRI, predispose these levels to degenerative changes postoperatively.

Histological Assessment of Degeneration of Anterior Cruciate Ligament in Arthritic Knee / 대한정형외과학회잡지

PURPOSE: To assess the histological findings of anterior cruciate ligament (ACL) degeneration in an arthritic knee and its correlation with the gross appearance of the ACL, the patient's age and the functional status of the knee. MATERIALS AND METHODS: Histological evaluations of the ACL were carried out on 80 patients who had total knee arthroplasty. Five types of ACL degeneration were noted; 1) mucoid degeneration, 2) liquefaction, 3) hyaline degeneration, 4) calcification, and 5) fissuring. A scoring system for the level of ACL degeneration was made. Each type of degeneration was scored and the degree of ACL degeneration was graded by summing each score. The correlation between ACL degeneration and patient's age, gross appearance, and functional evaluation of knee by Knee Society Score (KSS) was analyzed. The gross appearance of the ACL was classified as normal, abnormal (thinned or hypertrophied), and tear. RESULTS: The scores for the histological degeneration of the ACL ranged from 2 to 10, and there was no correlation between the patient's age and the scores (p>0.05). The gross appearance of the ACL was "nor-mal" in 19 cases, "abnormal" in 57, and "tear" in 4 with an average score of histological degeneration in 3.47 (2-6), 5.95 (3-10), and 9.0 (8-10) respectively. The score for the histological degeneration of the ACL was correlated with the gross appearance of the ACL and a functional evaluation by the KSS (p<0.05). CONCLUSION: The degree of ACL degeneration was not closely related to the patient's age but there was some relationship with the gross degenerative changes in the ACL and the functional loss of the knee.

The Biomechanical Responses of Intervertebral Disc due to Degenerative Change in Porcine Lumbar Spine / 대한정형외과연구학회지

PURPOSE: The biomechanical responses of degenerative porcine intervertebral disc were compared with those MATERIALS AND METHODS: Two groups were set; Group A (44.0+/-2.8 months old, female) and Group B (6.2 +/-1.3 months old, female). Histological (H&E stain) observations were carried out to see the degeneration for both groups. Then biomechanical responses were investigated by measuring height changes in disc, intradiscal pressure values and relaxation time for each specimen under axial compressive loads. RESULTS: Degenerative changes were confirmed through H&E staining in Group A. The ratios of the nucleus pulposus area to total area were 14.7+/-4.5% and 29.2+/-6.0% in Group A and B, respectively (p=0.000). The decrease rates in disc height were 12.1+/-3.3% and 21.6+/-7.6%, in Group A and B, respectively under the axial compression of 740 N (p=0.000). No significant difference in intradiscal pressure measured in anterior zone between-groups except at axial load of 740N (p> 0.05). However, significant difference in pressure was found in posterolateral zone when the load was 542 N and higher (542 N: p=0.015, 740 N: p=0.010). The average relaxation time for Group A was significantly longer than that for Group B at 740N, i.e., at maximum load (anterior: p=0.010, posterolateral: p=0.014). CONCLUSION: Different biomechanical responses in degenerative disc were confirmed. They are 1) less flexible, 2) slower in energy relaxation under axial loading, and 3) larger portion of the external load were taken up at posterior part of annulus fibrous, especially in degenerative disc.

Diagnostic Criteria to Differentiate Medial Meniscal Injury from Degenerative Changes on 99mTc-MDP Knee SPECT in Patients with Chronic Knee Pain / 대한핵의학회잡지

PURPOSE: In patients with chronic knee pain, the diagnostic performance of 99mTc-MDP knee SPECT for internal derangement of knee is deteriorated due to degenerative changes. In this study, we tried to establish diagnostic criteria to differentiate medial meniscal injury (MMI) from degenerative change (DC) when the uptake is increased in medial compartment. MATERIALS AND METHODS: A total of 49 knee SPECT of the patients with chronic (more than 3 months) knee pain, which showed increased 99mTc-MDP uptake in the medial compartment, were included in this study. The diagnosis was confirmed by arthroscopy. On knee SPECT, 3 diagnosic criteria for MMI were investigated. In Criterion I, MMI was diagnosed when crescentic uptake was observed in the medial tibial plateau. In Criterion II, crescentic uptake was further classified into anterior, mid, posterior, and diffuse patterns, according to the location of maximal uptake; and only crescentic mid, posterior, and diffuse patterns were diagnosed as MMI. In Criterion III, MMI was diagnosed when medial tibial plateau showed higher activity then medial femoral condyle. The diagnostic performance of the 3 criteria was compared. RESULTS: The sensitivity and specificity were 93% and 14% in Criterion I, 89% and 38% in Criterion II, and 75% and 67% in Criterion III, respectively. Criterion III had significantly improved diagnostic performance, especially, specificity. CONCLUSION: In this study, we established a practical diagnostic criterion to differentiate MMI from DC on knee SPECT. The result is helpful to improve the diagnostic value of knee SPECT as a screening test for chronic knee pain.

Myocardial Protective Effect of Cardioxane for the Myocardial Damage due to Doxorubicin

PURPOSE: To find out the myocardial protective effect of cardioxane for the myocardial damage by doxorubicin. METHODS: Using Eighteen rabbits(2.0-3.2 kg), doxorubicin(30 mg/m2) was injected intravenously once a week in group I(12 rabbits) and cardioxane(600 mg/m2) was injected at 20-30 minutes before doxorubicin administration in group II(6 rabbits). After this, we operated on the rabbits when the total cumulative dose of doxorubicin was reached at 210, 240, 270 and 300 mg/m2 and observed the degree of myocardial damage with light and electronic microscope. RESULTS: In group I, rabbits with less than 210 mg/m2 of total cumulative dose of doxorubicin, there was no definite myocardial damage but with 240 mg/m2, focal degenerative change was observed and with 300 mg/m2, severe degenerative change was detected with light microscopic examination. With electronic microscope, rabbits with less than 180 mg/m2 of total cumulative dose of doxorubicin in group I, there was no evidence of myocardial damage. In 210 mg/m2, focal degenerative change was detected. With 240 mg/m2, degenerative change was much more advanced and with 300 mg/m2, severe degenerative change was detected. In group II, no definite myocardial damage was observed even though the total cumulative dose of doxorubicin reached 300 mg/m2, but with 360 mg/m2, there was a focal area where myocardial fibers were somewhat decreased, but it's difficult to say whether these decrement were due to adriamycin in the electronic microscopic examination. CONCLUSION: Cardioxane have a good protective effect for the doxorubicin induced cardiomyopathy and it will be used safely in pediatric cancer patients.

Apoptosis in the meniscus of human osteoarthritic knee / 대한정형외과연구학회지

PURPOSE: The purposes of this study were to examine whether meniscal degeneration in human osteoarthritis(OA) was related with the occurrence of apoptosis, the expression of nitrotyrosine and Fas. MATERIALS AND METHODS: Menisci were obtained from OA patients undergoing total knee replacement arthroplasty and from normal subjects who were operated an above knee amputaton. According to histologic degeneration, menisci were graded to normal, grade 1(mild), grade 2(moderate), and grade 3(severe). Apoptotic cells were identified by TUNEL method and electron microscopy. Meniscal sections were analyzed by immunohistochemistry for the presence of nitrotyrosine and Fas expression. RESULTS: The number of apoptotic cells were significantly increased in OA meniscus compared with normal meniscus(p < 0.05). The number of apoptotic cells were increased with tissue degeneration. On electron microscopy, the typical chromatin condensation in the OA meniscus was shown in apoptotic cell. The number of Fas-expressing cells was significantly higher in the OA meniscus(p < 0.05). Nitrotyrosine immuno reactivity was prominent in the degenerative menisci(p < 0.05). Fas and nitrotyrosine expression were increased with degree of tissue degeneration. An increase in number of apoptotic cells was correlated with tissue degeneration but not with age . CONCLUSION: Apoptosis was suggested as one of the causes in the tissue degeneration of the human OA meniscus. The development of apoptosis in the meniscus may be related with Fas and nitrotyrosine expression but not with age.

Treatment for the Sequential Degenerative Changes at the Adjacent Segments to Lumbar Fusion / 대한척추외과학회지

STUDY DESIGN: A retrospective clinical and radiographic review. OBJECTIVES: To assess the treatment for the recurred symptoms caused by various sequential degenerative changes at the adja-cent segments to previous lumbar fusion. SUMMARY OF LITERATURE REVIEW: Accelerated degeneration of lumbar segments adjacent to a previous fusion has been established, but the treatment for this condition has rarely been demonstrated. MATERIALS AND METHODS: 19 consecutive patients who had treatments for the recurred symptoms caused by a sequential degenerative change at the adjacent segments were reviewed. The sequential changes at the adjacent segments were instability, disc space narrowing, spinal stenosis, and/or vertebral slip, and the symptoms of these changes were back pain in all patients and leg pain in many patients, particularly in later years. RESULTS: Initially all symptomatic patients were tried with conservative regimens of medication, physiotherapy, exercise, and education. A back brace was also applied for the patients who have considerable back pain, and the epidural injections for those who have leg pain. The symptoms of these patients, particularly the back pain were responded well to the conservative therapy during the earlier years, but surgery was needed eventually at the later years in 8 patients, particularly for the leg pain. For these patients, an adequate decompression and extension of the fusion using instrumentation resulted in good fusion with satisfactory clinical outcomes. CONCLUSION: The initial symptoms of the sequential degenerative changes at the adjacent segment after lumbar fusion were well responded to the conservative treatments, but a surgical treatment was needed eventually in many patients. The methods and results of the surgical treatment were similar to those of primary conditions.

Clinical Characteristics of Isolated Meniscal Tear / 대한정형외과학회잡지

PURPOSE: Of all meniscal tears, isolated meniscal tear accounted for about 20%~30%. Also only a few reports in the literature dealt with isolated meniscal tear, which has a lower repairability and healing rate compared to patients with meniscal tear associated with ACL rupture. This study was undertaken to evaluate the clinical characteristics of isolated meniscal tear. MATERIALS AND METHODS: Between June, 1996 and May, 1999, 170 cases confirmed to have a meniscal tear by arthroscopy, were included in this study. We analysed clinical characteristics, according to the type of injury, medial meniscal tear versus lateral meniscal tear, type and site of meniscal tear, as well as possibility of repair. RESULTS: The frequency of medial meniscus tear is more common than that of lateral meniscus tear. Additionally, the most common cause of meniscal tear was non- contact injury. Of the total isolated meniscal tears, 20.5% were repaired. CONCLUSION: In our case, the incidence of medial meniscus tear is higher than that of the lateral meniscus tear, but this study noted a significantly low incidence of repairablity in isolated meniscal tear. Based on preliminary findings in this study, we consider degenerative change of meniscus as the most important factor explaining the clinical characteristics of meniscus tear in patients, especially, over the age of 30.

Effect of Estrogen Receptor on Degenerative Change of Articular Cartilage in Adult Rabbit Knee / 대한정형외과학회잡지

The purpose of this study was to evaluate the effect of estrogen receptor on the degenerative change of articular cartilage by observation of different changes of histology, matrix glycosaminoglycan and chondrocyte proliferation. In sixty-four Newzealand rabbits, experimental instability was made to induce degenerative changes by sectioning the anterior cruciate ligament, medial collateral ligament and medial meniscus of the left knees. In the oophorectomy group (32 rabbits), knee surgery was performed at 6 weeks following bilateral oophorectomy. In the non-oophorectomy group (32 rabbits), knee surgery was performed without oophorectomy. Four rabbits were killed at 0, 1, 2, 4, 8, 12, 16, 20 weeks, respectively, after the knee operation. Total immunohistochemical scores of estrogen receptor were evaluated between the two groups. Histologic evaluation of H-E staining was conducted by alcian blue staining. Evaluation of chondrocyte proliferation was carried out by immunohistochemistry using monoclonal antibody to 5-bromo-2 -deoxyuridine. The stainability of each staining was calculated using semi-quantitative analysis and statistical differences were evaluat- ed by ANOVA test and LSD multiple comparison test. Total immunohistochemical scores of estrogen receptor in the non-oophorectomy group were higher than the oophorectomy group (P<0.05). In the non-oophorectomy group, the histologic scores and the histochemical scores of glycosaminoglycan were lower than the oophorectomy group after 4 weeks and 8 weeks respectively (P<0.05). The immunohistochemical score of BrdU was the highest at 2 week and then decreased after 4weeks in both groups. The immunohistologic scores of non-oophorectomy group was significant higher than oophorectomy group between 1 and 4 weeks (P<0.05). Our results suggested that the estrogen might aggravate the degenerative change of the knee joint in rabbits by decreasing matrix glycosaminoglycan and increasing chondrocyte proliferation.

Clinical Analysis of Less Extensive Microsurgical Decompression for Lumbar Spinal Stenosis

The cases of twenty-eight patients with spinal stenosis treated by microscopic decompressive surgery from January 1991 to September 1995, were analysed in an attempt to define is clinical feature, and to evaluate the results of our modified operation technique of preventing postoperative spinal instability. The main age group of the patients were in the fifties and sixties. On plain X-ray, most lumbar spine of the patients showed degenerative change. Pain in lower back and legs were the most common symptom, and intermittent neurogenic claudication was presented in three quarters of the patients. Radiologically, the diagnosis was confirmed by either myelography, CT, and MRI or by their combination. The major etiologic factors were thickening of ligamentum flavum, hypertrophy of laminae or facet joints and associated herniated nucleus pulposus. Since a significant rate of postdecompressive instability had been reported by other authors, therefore we have decided to performed less extensive decompressive total laminectomy procedure. The outcome of our decompressive laminectomy was favorable. In patients with no preoperative instability, newly developed instability following the less extensive decompressive total laminectomy was none.

Histopathologic Features of Gastric Mucosa Colonized by Helicobacter pylori

TO evaluate the histopathologic features of gastric mucosa by Helicobacter pylori (HP), we reviewed 70 endoscopically biopsied chronic gastritis and peptic ulcer. The results are as fonows. l. HP was detected in 923% (48/52) of active gastritis, 8l8% (9/l l) of peptic ulcer and l43% (1/7) of chronic gastritis. The prevalence of HP infection was significantly higher in active gastritis and peptic ulcer than chronic gastritis (P<0005). 2. The infiltration of intraepithelial neutrophil of the 58 HP-positive cases was significantly more than of the l2 HP-negative cases (P<0005). 3. The infiltration of neutrophil and chronic inflammatory cells in the lamina propria of the 58 HP positive cases were significantly more than of 12 HP-negative cases (P<0.005, P<0.01) 4. The gastric epithelium of 58 HP positive case showed characteristic degenerative change, such as epithelial pits (93.l%), irregular surface (84.4%), individua1 cell drop-out (46.5%) and microerosion (27.6%). The similiar changes were not seen in l2 HP-negative cases. In summary, HP is significantly correlated with inflammatory reaction of the gastric mucosa. It is also significantly correlated with the epithelial degenerative changes that is considered to the precursor of peptic ulcer.

The effects of changes of mandibular position on temporomandibular joint in adult rabbits whose retrodiscal tissues were incised / 대한치과교정학회지

The purpose of this experiment was to study the effects of changes of mandibular position on temporomandibular joint in internal derangement patients. Twenty-four female New Zealand White Rabbits, weighing over 3.5kg, were utilized in this study. Bilateral temporomandibular joint surgery was performed in twenty one of the rabbits to displace disc anteriorly through incising the retrodiscal tissue 1-2mm posterior to the disc, thus inducing internal derangement. They were divided into three groups: nine were left untreated after surgery, six were fitted with functional protrusive appliances 4 weeks after surgery, and six wore collar appliances to apply 4 ounces of mandibular retractive force per side 4 weeks after surgery. The remaining three served as the control group. Histologic examinations were performed after sacrificing them by threes at 4-week intervals. The results were as follows: 1. Histologic findings similar to internal derangement were observed in the rabbits whose retrodiscal tissues had been incised. 2. In the rabbits untreated after surgery, articular surface on condylar process and articular eminence showed severe erosion and deformation, and displaced disc manifested changes in both shape and internal architecture. 3. Functional protrusion after surgery resulted in progressive remodeling on posterosuperior portion of condyle and glenoid fossa, while it also brought about erosion on articular eminence and anterior portion of condyle. 4. Mandibular retraction after surgery resulted in compression of retrodiscal tissue and regressive remodeling of posterior portion of condyle.