• Title/Summary/Keyword: Hwang Sang

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Effects of HapKok (LI-4) , SamUmGyo (SP-6) Acupuncture on Uterine Motility and Cyclooxygenase-2 Manifestation in Rats (합곡(合谷), 삼음교(三陰交) 자침(刺鍼)이 백서(白鼠) 자궁(子宮) 운동(運動) 및 Cyclooxygenase-2 발현(發現)에 미치는 영향(影響))

  • Lee, Byung-Chul;Lee, Ho-Sub;Kim, Kyung-Sik;Lee, Geon-Mok;Na, Chang-Soo;Kim, Jung-Sang;Hwang, Woo-Jun
    • Journal of Acupuncture Research
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    • v.17 no.2
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    • pp.187-208
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    • 2000
  • By the activation of ovary hormone, many morphological changes occur in the epithelial cell lines and muscle cells in rat uterus. These two cells in uterus are important to the implantation of embryo, maintaining pregnancy and starting parturition. One important change associated with the morphological change of these two cells in uterus is the change on prostaglandin(PG) metabolism. Its presence and synthesis in endometriurn and myometrium in uterus affects estrous cycle and the start of embryo implantation in uterus. It also performs as an important modulator in parturition. So the abnormally weak expression of PG causes difficulty during labor and over-expression causes pre-term labor. PG biosynthesis starts from either free or liberated arachidonic acids from membrane phospholipid by phospholipase. Such arachidonic acids are converted into PG catalyzed by Cyclooxygenase. Under normal physiological condition, Cyclooxygenase-1(COX-1) having 602 units of amino acids controls the synthesis of PG. It acts as a local hormone regulating vasomodulation of blood flow, flexible muscle movement, increasing the blood permeability and contributing the protective role in preserving integrity of the stomach lining and Cyclooxygenase-2 (COX-2) is induced by the inflammation, pregnancy and increased its expression until parturition. Lipid metabolite like PG is located in uterine and expression of COX-2 increased with pregnancy. Increased expression of COX proteins in epithelial cells and myometrial cells are told to increase the muscle contractility in uterus but decreased right after the labor in rat. It is a good sign indicating that COX proteins are deeply related to the start of labor. Currently, Several studies report the use of PG and COX-2 inhibitor as medication for controlled abortion or to prevent pre-term labor but they entail various side-effects. Our study proposed to suggest use of acupuncture as an another mediator to control abortion or pre-term labor without causing unnecessary side-effects by those medicines. Two acupuncture sites, LI-4 & SP-6 were selected due to their known efficacy. From the immunohistochemical staining of COX-2, normal expression of COX-2 protein in nonpregnant SD rat's uterus revealed that COX-2 protein was primarily detected in the lumina epithelial lining and in the epithelial cell lining contacting the stromal cells. High resolution optical microscopic scanning revealed distinguishable staining in the myometrial mucosa. LI-4 acupuncture administered nonpregnant rat's uterus showed strong expression for COX-2 in endometrium contacted with lumina epithelial lining of rat uterus and in myometrial mucosa. Stromal cells showed more staining than untreated nonpregnant rat's uterus and stronger staining in stromal cells contacting myometrial layer compared to untreated nonpregnant rat's uterus. SP-6 acupuncture administered nonpregnant rat's uterus showed weak expression for COX-2 in myometrial layers and stromal cells but no staining was visible in lumina epitheliai and glandular epithelial cells. Few stromal cells and myometrial mucosa were positively stained for COX-2. Pregnant SD rat's uterus was also immunostained for COX-2 expression after 18 days of pregnancy. Unlike to untreated nonpregnant rat's uterus, luminal epithelial cells were not positively stained for COX-2 but stronger staining for COX-2 was revealed in stromal cells. LI-4 acupunctured SD rat's uterus had very strong expression of COX-2 in luminal epithelial lining. Few stromal cells showed stronger positive COX-2 staining and myometrial layers also showed more expression than untreated pregnant rat. SP-6 acupuncture administered pregnant SD rat's uterus showed positive expression of COX-2 in epithelial cells of luminal mucosa layer but weaker than that of LI-4 acupuncture treatment's case. However, strong positive staining was revealed in stromal mucosa and myometrial layers. Virgin SD rat's uterus motility index during LI-4 acupuncture was 66.52 % (Prob〉T = 0.0197) compared to its motility before the acupuncture treatment but the motility index was slighdy elevated up to 79.58 % (Prob〉T = 0.1175) after the acupuncture. During the SP-6 acupuncture treatment for 30 minutes, uterus motility index was 90.52 % (Prob〉T = 0.1832) showing lesser decrement but consequently reached similar motility index decreasal to 79.95 % (Prob〉T = 0.0215) after the acupuncture treatment as LI-4 showed. LI-4 acupuncture tend to be a quick treatment to reducing the uterus motility in a virgin rat but eventually both two acupuncture administration created very similar reduction of uterus motility seeing the index after the both acupunctures. The uterus movement monitored during the LI-4 acupuncture administered for 30 minutes, Pregnant SD rat showed decreased motility down to 77.90 % (Prob〉 T = 0.0076) compared to uterus motility before the acupuncture and it continuously decreased down to 71.81 %(Prob〉T = 0.0214) after the removal of needle. The statistical analysis using paired t-test showed significance difference for both two motility indexs at =0.05. SP-6 acupuncture administered to pregnant SD rat also had similar pattern of decreasing uterus motility index down to 74.70 % (Prob〉T = 0.1730) during the initial 30 minutes acupuncture administration and it was continuously lowered to 71.52 % (Prob〉T = 0.0155) after the acupuncture. The paired t-test resuit for SP-6 suggest prompt response of uterus motility index to the SP-6 acupuncture treatment but consequently reached same level of inducing the motility reduction as LI-4 at =0.05 level.

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A Study on Relationship between Degree of Stress and Dyspepsia, Sleeping, Satisfaction of Adult Women in Rural Area (성인 여성들의 스트레스와 소화불량 및 수면장애와의 관련성)

  • Kim, Yeong-Hee;Cho, Soo-Yeul;Kang, Pock-Soo;Lee, Kyeong-Soo;Kim, Seok-Beom;Kim, Sang-Kyu;Kang, Young-Ah;Hwang, Young-Lork
    • Journal of agricultural medicine and community health
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    • v.25 no.1
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    • pp.51-63
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    • 2000
  • Ten Dongs were selected according to the systematic cluster sampling in Koryong Gun, and the survey was conducted on 571 women in the age between 30-69 years. The first survey was performed for 6 days between August 27 to September 1, 1999 with the investigation rate of 60.3%, and the second survey was performed in November with the investigation rate of 91.8%. The contents of survey included demographic characteristics, health behaviors, dyspepsia symptom score, sleeping induction time and the degree of sleep satisfaction, and degree of stress in the subjects. The dyspepsia symptom score was in the average 13.4 points out of a total 44 points and was the highest in the 50-59 year-old age group with 13.9 points. The sleep induction time was in the average of 35 minutes and was the highest in the 50-59 year-old age group with 40.9 minutes; the degree of sleep satisfaction was in the average of 7.9 points and was the lowest in the 50-59 year-old age group with 7.5 points. The stress score was in the average of 18.3 points and was highest in those subjects in their 40's and 50's with 18.7 points. When the correlation among the stress score, the degree of sleep satisfaction and dyspepsia symptom score was analyzed, the results showed that he stress score and the degree of sleep satisfaction showed a significant negative correlation and that the stress score and dyspepsia symptom score showed a significant positive correlation. Also, a significant negative correlation was found between the degree of sleep satisfaction and dyspepsia symptom score. According to each age group, a significant correlation was revealed among the stress score, dyspepsia symptom score and the degree of sleep satisfaction in those subjects over 40 years of age compared to those subjects who were younger than 40 years of age. As for educational level, the correlation among the stress score, the degree of sleep satisfaction and dyspepsia symptom score was higher in those subjects with less than middle school education compared to those subjects with more than high school education. When those factors that effects on the dyspepsia symptom score were analyzed with multiple regression, the results showed that the level of stress and chronic diseases were selected as significant variables. When those factors that affected on the degree of sleep satisfaction were analyzed, the sleep induction time and presence of chronic diseases and stress were selected as significant variables. Those women in their 50's who live in rural areas showed the highest level of stress, lowest the degree of sleep satisfaction, and highest level of dyspepsia, indicating that they need stress management. Also, since stress was showed to be a significant variable effecting on dyspepsia or the degree of sleep satisfaction, it is concluded that health promotion is possible through stress management. More studies are needed in the future on coping resources that would strengthen coping against stress, and by conducting studies on stress and related factors on community people, the measures of mental health promotion need to be developed.

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Role of PI3K/Akt Pathway in the Activation of IκB/NF-κB Pathway in Lung Epithelial Cells (폐 상피세포에서 PI3K/Akt 경로가 IκB/NF-κB 경로의 활성화에 미치는 영향)

  • Lee, Sang-Min;Kim, Yoon Kyung;Hwang, Yoon-Ha;Lee, Chang-Hoon;Lee, Hee-Seok;Lee, Choon-Taek;Kim, Young Whan;Han, Sung Koo;Shim, Young-Soo;Yoo, Chul-Gyu
    • Tuberculosis and Respiratory Diseases
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    • v.54 no.5
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    • pp.551-562
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    • 2003
  • Background : NF-${\kappa}B$ is a characteristic transcriptional factor which has been shown to regulate production of acute inflammatory mediators and to be involved in the pathogenesis of many inflammatory lung diseases. There has been some evidence that PI3K/Akt pathway could activate NF-${\kappa}B$ in human cell lines. However, the effect of PI3K/Akt pathway on the activation of NF-${\kappa}B$ varied depending on the cell lines used in the experiments. In this study we evaluated the effect of PI3K/Akt pathway on the activation of NF-${\kappa}B$ in human respiratory epithelial cell lines. Methods : BEAS-2B, A549 and NCI-H157 cell lines were used in this experiment. To evaluate the activation of Akt activation and I${\kappa}B$ degradation, cells were analysed by western blot assay using phospho-specific Akt Ab and $I{\kappa}B$ Ab. To block PI3K/Akt pathway, cells were pretreated with wortmannin or LY294002 and transfected with dominant negative Akt (DN-Akt). For IKK activity, immune complex kinase assay was performed. To evaluate the DNA binding affinity and transcriptional activity of NF-${\kappa}B$, electrophoretic mobility shift assay (EMSA) and luciferase assay were performed, respectively. Results : In BEAS-2B, A549 and NCI-H157 cell lines, Akt was activated by TNF-$\alpha$ and insulin. Activation of Akt by insulin did not induce $I{\kappa}B{\alpha}$ degradation. Blocking of PI3K/Akt pathway via wortmannin/LY294002 or DN-Akt did not inhibit TNF-$\alpha$-induced $I{\kappa}B{\alpha}$ degradation or IKK activation. Inhibition of PI3K/Akt did not affect TNF-$\alpha$-induced NF-${\kappa}B$ activation. Overexpression of DN-Akt did not block TNF-$\alpha$-induced transcriptional activation of NF-${\kappa}B$, but wortmannin enhanced TNF-$\alpha$-induced in NF-${\kappa}B$ transcriptional activity. Conclusion : PI3K/Akt was not involved in TNF-$\alpha$-induced $I{\kappa}B{\alpha}$ degradation or transcriptional activity of NF-${\kappa}B$ in human respiratory epithelial cell lines.

Monitoring of Pesticide Residues Concerned in Stream Water (전국 하천수 중 잔류우려 농약 실태조사)

  • Hwang, In-Seong;Oh, Yee-Jin;Kwon, Hye-Young;Ro, Jin-Ho;Kim, Dan-Bi;Moon, Byeong-Chul;Oh, Min-Seok;Noh, Hyun-Ho;Park, Sang-Won;Choi, Geun-Hyoung;Ryu, Song-Hee;Kim, Byung-Seok;Oh, Kyeong-Seok;Lim, Chi-Hwan;Lee, Hyo-Sub
    • Korean Journal of Environmental Agriculture
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    • v.38 no.3
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    • pp.173-184
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    • 2019
  • BACKGROUND: This study was carried out to investigate pesticide residues from fifty streams in Korea. Water samples were collected at two times. Thee first sampling was performed from april to may, which was the season for start of pesticide application and the second sampling event was from august to september, which was a period for spraying pesticides multiple times. METHODS AND RESULTS: The 136 pesticide residues were analyzed by LC-MS/MS and GC/ECD. As a result, eleven of the pesticide residues were detected at the first sampling. Twenty eight of the pesticide residues were detected at the second sampling. Seven pesticides were frequently detected from more than 10 water samples. Ecological risk assessment (ERA) was carried out by using residual and toxicological data. Four scenarios were applied for the ERA. Scenario 1 and 2 were performed using LC50 values and mean and maximum concentrations. Scenarios 3 and 4 were conducted by NOEC values and mean and maximum concentrations. CONCLUSION: Frequently detected pesticide residues tended to coincide with the period of preventing pathogen and pest at paddy rice. As a result of ERA, five pesticides (butachlor, carbendazim, carbofuran, chlorantranilprole, and oxadiazon) were assessed to be risks at scenario 4. However, only oxadiazon was assessed to be a risk at scenario 3 for the first sampling. Oxadiazon was not assessed to be a risk at the second sampling. It seems to be temporary phenomenon at the first sampling, because usage of herbicides such as oxadiazon increased from April to march for preventing weeds at paddy fields. However, this study suggested that five pesticides which were assessed to be risks need to be monitored continuously for the residues.

A Study of Perspective on Cheon Gwan(天觀) of Toegye (퇴계(退溪)의 천관(天觀) 연구(硏究))

  • Hwang, Sang Hee
    • (The)Study of the Eastern Classic
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    • no.56
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    • pp.147-170
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    • 2014
  • To divide by the concept of Cheon (天) before and after the period of Song Dynasty: before Song Dynasty; according to the ancient Book of Odes (Sigyeong-詩經), "Cheon (天) gives birth to a large number of people", and, Confucius(孔子) say "Cheon(天) gave me Virtue(德)." Mencius(孟子) say "The person done with all his heart knows Seong(性, personality), so if he knows such Seong(性, personality), then he knows Cheon(天)." In Doctrine of the Mean(中庸), it says "Cheon(天) ordered it to be called - Seong(性, personality)." So, Cheon(天) had a religious meaning, such as Sangje(上帝) - Supreme Ruler. During the Song period, Cheon(天), the source of its existence, had construed as Mugeuk i Taegeuk Non(無極而太極論 - Theory of Supreme Ultimate while being Indeterminate) and Theory of li and ki (iginon-理氣論). Juja (朱子, a honorary name of Juhui, 朱熹) had said a reasonable Cheon(天), that is, Heavenly Principle (天理 - Cheolli) by interpreting Cheon(天) as Taegeuk(太極 - Supreme Polarity) and li(理) of Muwi(無爲 - uncontrived action). That's why Juja had lost the religiosity because of his reasonable frame. The purpose of this dissertation is to identify of the quality of being religious of li(理) on the basis of attribute of Cheon(天) argued by Toegye and Juja. In the text of Seomyeong(西銘 - Western Inscription), we can see their interpretation of the content that Toegye as "西銘考證講義"(Lecture on Historical Research of Western Inscription), and Juja as "西銘解"(Commentary on the Western Inscription). Seomyeong(西銘 - Western Inscription) was expounded as a logic of 'iil bunsu' (理一分殊 - coherence is one and distinguished into many). '理一分殊' means to live in as meaningful as possible according to the human nature that has been bestowed upon thyself. Juja and Toegye both said that in the aspect of 'iil'(理一 - coherence is one), Reverence(事天) ought to be done, but to look into the aspect of 'bunsu'(分殊-distinguished into many), Juja argued that people should follow the order of Heavenly Principle(天理 - Cheolli), and Toegye argued that people should have to perform the filial piety(孝). There are differences in methods of Toegye and Juja on account of distinction between attributes of Cheon(天). Such a distinction affects the attribute of li(理). Juja said divisively that Soiyeon(所以然-why its principle is so) is li(理), and Sodangyeon(所當然-what should be so) is Sa(事-divine project). Toegye argued that Sodangyeon(所當然-what should be so) is indeed li(理). It is the position of Toegye that to know Seong(性-the personality) of Sodangyeon(所當然-what should be so) is the first, rather than to know Cheon(天) of Soiyeon(所以然-why its principle is so) that is out of reach in a faraway place. Seong(性-the personality) is li(理) that bestowed by Cheon(天). In view of discussion about the essence and existence, for Toegye, the existence is the first, rather than the essence. The issues of existence is now enabled to talk about amid the discussion of metaphysics, namely li(理). Different from Juja, a theory noticed in Toegye is the theory of 'Lijado'(理自到). 'Lijado'(理自到) denotes 'Li(理) leads on their own.' It tells that separate from thing-in-itself, there is an energy that moves and oversees the thing. This is an issue of response between "I" as the principal agent and other people. If "I" as the principal agent is sincere to others, the others will come to me insomuch as they will be revealed through me. Here, a problem between the host and guest arises. Toegye perceived this problem that do not see me and others as same, and also do not see me and others as two. This is the logic of 'ilii iiil'(一而二 二而一 - looks like one but two, looks like two but one) of '理一分殊' (coherence is one and distinguished into many). The first thing to do between these two processes is to recognize the existence of 'iil'(理一). Toegye strongly displays a religious attitude identifying Cheon(天)=Li (理)=Sangje(上帝- Supreme Ruler) in the same light.

Survey Studies on Serviceable Sericultural Communities in Korea (養蠶適地選定에 관한 調査硏究)

  • Choe, Byong-Hee;Gwon, Yeong-Ha;Mun, Jae-Yu;Baek, Hyeon-Jun;Lee, Geon-Yeong;Lee, Sang-Pung;Lee, Won-Ju;Im, Su-Ho;Jo, Dong-Ok;Kim, Seong-Ho;Hwang, Hong-Do;Kim, Gi-Seok;Kim, Su-Gyeong;Go, Nak-Yong;So, Byeong-Ju;Lee, Geon-U;Lee, Jae-Ok;Im, Dong-Rak;Jo, Jin-Gu
    • Journal of Sericultural and Entomological Science
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    • v.25 no.1
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    • pp.34-43
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    • 1983
  • These studies have been carried out to find better locations for sericultural service regardless of the international silk market fluctuation in Korea. In order to acieve the purpose, various investigations and analyses have been carried out for more than four hundred sericultural communities to find out the main factors which caused to decrease in cocoon production in spite of a gloomy past silk market. Now, we believe that we have set up some fundamental guide lines in developing sound serviceable sericultural communities in Korea in case the government accepts the written advices, and the results obtained are as follows: 1. The Korean sericulture has been very prosperous from the 60's to the 70's. In 1976 the cocoon production was at its peak, reaching 41,704M/T from which its decline took place with annual averages of 18.5% for total cocoon production and 16.4% for mulberry field. These figures represent a quantitative decrease to one-third of the total amount in 1976. Since then, the Korean sericulture had continuously suffered from a shortage of raw silk resulting in a slow development of sericulture. At present, a steady development through all possible measures is great importance. 2. The downfall of the korean sericulture resulted from two factors of such as the external, which led to the decline in the price of raw silk at the international market and restrain of import and, the internal, resulting in the little increase of cocoon price and a comparatively lower benefits from the sericulture than from other cash crops. 3. The already established sericultural zone collapsed and then reorganized with the outstanding regional specialization so the decline in total cocoon production in the country. Based on the agricultural regions, 1980 cocoon production was very stable in the mountaineaus area of the east-south which used with intercropping. In this area there was small decline of 33% compare with that of the 1979, and with 70% decline in the dry field farming area of Kangwon Do. In an administrative districtwise, six counties beginning with Sanchnung county of Kyungsang Nam Do, showed less than 20% decline of cocoon production, sixteen counties beginning with Samchuck county of Kangwon Do marked above 80% decrease of cocoon production. In the smaller unit area-wise, there was a big difference among them. twenty-five myons rather increased and a hundrd fourty-three myons decreased above 80% of it. 4. The cocoon production was positively correlated with the decreasing percentage of cocoon production per household. It was also affected by the ratio of the mulberry field area to the total cultivated area per household and cocoon productivity per 10a. 5. Four hundred sixty-four villages in the seventeen counties were surveyed on the basis of farm management and techniques concerned ('80/'79), and then the results were evaluated by using of computer. These results are summarized as foolows: (1) Cocoon production per household There was no difference among the agricultural regions in cocoon production. The cocoon production per household in the comparatively stable villages increased from 100.8kg in 1979 to 122kg in 1981. Cocoon yield in the stable villages decreased by 20% of '81/'79. The cocoon production per house hold in while that of the unstable villages decreased by more than 40% from 102.9kg in 1979 to 82kg in 1981. (2) Cocoon yield per 10a mulberry field The cocoon yield per 10a was higher in the plain area than in the mountaineous area. The stable villages had an average of 73.4kg cocoon yield/10a while the unstabe ones had only an average of 55kg. (3) Adoption the mulberry branch rearing method The branch rearing method was more popular in the plain area than in the mountainous area. In the stable vilages adopted 24.2% in spring and 16.7% in autumn of 1979. In 1981 it shwed increases of 34.3% and 10.1% in the two seasons respectivly. However, the unstable villages showed 13.3% and 126% in both seasons, respectively. (4) The patterns of the combined management system in the sericultural farming The popular management system in the sericultural from was combined with rice and other cash crops, showing 55% of the total households surveyed. Fourteen percent of the households combined the management system with rice and other cash crops and 14% of the households combined with rice only. The villages wich earned less than 20% of the total income from the sericulture reached 81% of the total houscholds indicating that they were still far beyond a complete combination system. (5) Damage by agricultural chemicals The damage caused by agricultural chemicals was mainly due to the protection of rice against insectpests and diseases in the plain areas and took place mostly in the autumn season. The chemicals applied was 65% of Iiquid and 35% of powder forms and 35% of damage was from granulat form of the chemicals. The use of the granular chemicals was low because of high cost.

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Comparisons of Unicortical and Bicortical Lateral Mass Screws in the Cervical Spine : Safety vs Strength (경추부의 후관절 나사못 고정술에서 단피질삽입법과 양피질 삽입법 간의 특성에 관한 비교)

  • Park, Choon-Keun;Hwang, Jang-Hoe;Ji, Chul;Lee, Jae Un;Sung, Jae Hoon;Choi, Seung-Jin;Lee, Sang-Won;Seybold, Eric;Park, Sung-Chan;Cho, Kyung-Suok;Park, Chun-Kun;Kang, Joon-Ki
    • Journal of Korean Neurosurgical Society
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    • v.30 no.10
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    • pp.1210-1219
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    • 2001
  • Introduction : The purpose of this study was to analyze the safety, pullout strength and radiographic characteristics of unicortical and bicortical screws of cervical facet within cadaveric specimens and evaluate the influence of level of training on the positioning of these screws. Methods : Twenty-one cadavers, mean 78.9 years of age, underwent bilateral placement of 3.5mm AO lateral mass screw from C3-C6(n=168) using a slight variation of the Magerl technique. Intraoperative imaging was not used. The right side(unicortical) utilized only 14mm screws(effective length of 11mm) while on the left side to determine the length of the screw after the ventral cortex had been drilled. Three spine surgeons(attending, fellow, chief resident) with varying levels of spine training performed the procedure on seven cadavers each. All spines were harvested and lateral radiographs were taken. Individual cervical vertebrae were carefully dissected and then axial radiographs were taken. The screws were evaluated clinically and radiographically for their safety. Screws were graded clinically for their safety with respect to the spinal cord, facet joint, nerve root and vertebral artery. The grades consisted of the following categories : "satisfactory", "at risk" and "direct injury". Each screw was also graded according to its zone placement. Screw position was quantified by measuring a sagittal angle from the lateral radiograph and an axial angle from the axial radiograph. Pull-out force was determined for all screws using a material testing machine. Results : Dissection revealed that fifteen screws on the left side actually had only unicortical and not bicortical purchase as intended. The majority of screws(92.8%) were satisfactory in terms of safety. There were no injuries to the spinal cord. On the right side(unicortical), 98.9% of the screws were "satisfactory" and on the left side(bicortical) 68.1% were "satisfactory". There was a 5.8% incidence of direct arterial injury and a 17.4% incidence of direct nerve root injury with the bicortical screws. There were no "direct injuries" with the unicortical screws for the nerve root or vertebral artery. The unicortical screws had a 21.4% incidence of direct injury of the facet joint, while the bicortical screws had a 21.7% incidence. The majority of "direct injury" of bicortical screws were placed by the surgeon with the least experience. The performance of the resident surgeon was significantly different from the attending or fellow(p<0.05) in terms of safety of the nerve root and vertebral artery. The attending's performance was significantly better than the resident or fellow(p<0.05) in terms of safety of the facet joint. There was no relationship between the safety of a screw and its zone placement. The axial deviation angle measured $23.5{\pm}6.6$ degrees and $19.8{\pm}7.9$ degrees for the unicortical and bicortical screws, respectively. The resident surgeon had a significantly lower angle than the attending or fellow(p<0.05). The sagittal angle measured $66.3{\pm}7.0$ degrees and $62.3{\pm}7.9$ degrees for the unicortical and bicortical screws, respectively. The attending had a significantly lower sagittal angle than the fellow or resident(p<0.05). Thirty-three screws that entered the facet joint were tested for pull-out strength but excluded from the data because they were not lateral mass screws per-se and had deviated substantially from the intended final trajectory. The mean pull-out force for all screws was $542.9{\pm}296.6N$. There was no statistically significant difference between the pull-out force for unicortical($519.9{\pm}286.9N$) and bicortical($565.2{\pm}306N$) screws. There was no significant difference in pull-out strengths with respect to zone placement. Conclusion : It is our belief that the risk associated with bicortical purchase mandates formal spine training if it is to be done safely and accurately. Unicortical screws are safer regardless of level of training. It is apparent that 14mm lateral mass screws placed in a supero-lateral trajectory in the adult cervical spine provide an equivalent strength with a much lower risk of injury than the longer bicortical screws placed in a similar orientation.

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