Missing values and outliers are frequently encountered while collecting data. The presence of missing values reduces the data available to be analyzed, compromising the statistical power of the study, and eventually the reliability of its results. In addition, it causes a significant bias in the results and degrades the efficiency of the data. Outliers significantly affect the process of estimating statistics (e.g., the average and standard deviation of a sample), resulting in overestimated or underestimated values. Therefore, the results of data analysis are considerably dependent on the ways in which the missing values and outliers are processed. In this regard, this review discusses the types of missing values, ways of identifying outliers, and dealing with the two.
Bias (Epidemiology) ; Data Collection ; Statistics as Topic

Background: Researchers who use the results of statistical analyses to draw conclusions about collected data must write a statistical analysis section in their manuscript. Describing statistical analyses in precise detail is as important as presenting the dosages of drugs and methodology of interventions. It is also essential for scientific accuracy and transparency in scientific research. Methods: We evaluated the quality of the statistical analysis sections of clinical research articles published in the Korean Journal of Anesthesiology between February 2020 and February 2021. Using a Likert scale where 1, 2, and 3 represented “not described at all,” “partially described,” and “fully described,” respectively, the following 6 items were assessed: 1) stating of the statistical analysis methods used, 2) rationale for and detailed description of the statistical analysis methods used, 3) parameters derived from the statistical analyses, 4) type and version of the statistical software package used, 5) significance level, and 6) sidedness of the test (one-sided vs. two-sided). The first 3 items evaluate issues directly related to the statistical analysis methods used and last 3 are indirectly related items. Results: In all the included articles, the statistical analysis methods used were stated (score of 3). However, only 4 articles (12.9%) fully described the sidedness of the test (score of 3). Conclusions Authors tend not to describe the sidedness of statistical analysis tests in the methodology section of clinical research articles. It is essential that the sidedness be described in research studies.

We report a case of acute transient encephalopathy with mental alteration, myoclonic jerks, and periodic triphasic wave electroencephalographic patterns caused by a therapeutic dose of baclofen. The clinical and electroencephalo-graphic abnormalities improved to a normal range shortly after baclofen was discontinued. We discuss the pathogenesis and review the literature about baclofen-induced encephalopathies.
Baclofen ; Myoclonus ; Reference Values

STUDY DESIGN: A retrospective study. OBJECTIVE: To analyze the clinical significance of the radiolucent zones surrounding pedicle screws. SUMMARY OF LITERATURE REVIEW: Clear zones have been suggested in pseudoarthrosis and a loss of fixation. However, few reports have clearly described the long-term course and clinical significance of clear zones. MATERIALS AND METHODS: The clear zones were evaluated in 399 patients with pedicle screw fixation after 6 months, 1 year, 2 years and 3 years. The patient was considered to be clear zone positive when 1 mm or greater circumferential lucency was confirmed around a screw on film from 2 or more directions. The time-course of the clear zones was examined with regard to age, number of levels fused, bone union, fusion method and reoperation. RESULTS: After 6 months, clear zones were observed in 124 patients (31.1%) but the clear zone-positive rate decreased with time. Clear zones were observed in 89 patients(22.3%), 44 patients(11.0%) and 41 patients(10.3%) after 1 year, 2 years and 3 years, respectively. No new clear zones had developed after 6 months. At the final follow-up, pseudoarthrosis was observed in 12 patients(3.0%). Among them, 11 were clear zone-positive and 1 was clear zone-negative. There was a statistically significant relationship between the clear zone-positive rate and multi-levels, older age and nonunion during following up. In addition, there was a relatively lower clear zone-positive rate in posterolateral fusion combined with posterior lumbar interbody fusion than only posterolateral fusion. However, the difference between them was not statistically significant. CONCLUSION: The presence of clear zones does not always mean pseudoarthrosis but clear zones persisting for more than 2 years after surgery have a higher rate of pseudoarthrosis.
Follow-Up Studies ; Humans ; Pseudarthrosis ; Reoperation ; Retrospective Studies

Objectives: ：The purpose of this study was to identify suicide risk factors among elderly residents in Gyeongsangbuk-do and to reveal the relationships between them. In addition, the differences in suicide risk factors were analyzed between the cognitively impaired group and the cognitively normal group. Methods: ：We investigated 20,127 elderly over 65 years of age, from January 2019 to December 2019. Participants were asked to complete a questionnaire survey. Cognitive function, depression, anxiety, sleep disturbance, and suicidal ideation data were assessed using a Korean version of the Mini-Mental Status Examination for Dementia Screening (MMSE-DS), Short Geriatric Depression Scale for Korean version (S-GDS), Geriatric Anxiety Inventory (GAI), Athens Insomnia Scale (AIS), and Scale for Suicidal Ideation (SSI). Data were analyzed using the chi-squared test and logistic regression analysis to examine suicide risk factors and the relationships between them. Furthermore, differences in suicide risk factors according to cognitive function were examined. Results: ：Age, cognitive function, depression, anxiety, and sleep disturbance were identified as suicide risk factors among elderly residents in Gyeongsangbuk-do. Depression was the factor that increased risk of suicide the most, followed by anxiety, impaired cognitive function, sleep disturbance, and 65-74 years of age. In addition, depression increased risk of suicide by 1.86 times in the cognitively impaired group. Conclusions ：Among elderly residents in Gyeongsangbuk-do, depression was the factor that contributed the highest risk for suicide. More active prevention and treatment measures for depressive symptoms should be implemented in the cognitively impaired group.

STUDY DESIGN: Thirty-seven patients with spinal tuberculosis were evaluated according to surgical method. OBJECTIVES: To evaluate the effectiveness of posterior spinal instrumentation in the surgical treatment of patient with tuberculous spondylitis. SUMMARY OF LITERATURE REVIEWS: There are many debates about the effectiveness of posterior spinal instrumentation combined with anterior interbody fusion in tuberculous spondylitis. MATERIALS AND METHODS: From January 1995 to June 2000, 37 patients were divided into two groups depending on their use of posterior spinal instrumentation. Group I consist of thirteen patients who were treated with conventional anterior corpectomy and anterior interbody fusion using autogenous strut bone graft. Group II was composed of twenty-four patients who were treated with conventional anterior corpectomy and anterior interbody fusion combined with posterior spinal instrumentation. Changes of corrected kyphotic angle and complication were measured using pre-, post-operative and follow-up radiographs and chart review. RESULTS: In group I, six cases (46.2%) showed loss of corrected kyphotic angle. Of these six cases, five cases had initial kyphotic angle of more than 20 dgree and three cases had involvement of two or more vertebrae. All six cases had thoracic or thoracolumbar involvement. Comparing two groups, maintaining corrected kyphotic angle and low complication rates were obtained in group II during follow-up period. The change of deformity as followed. In thoracic area, the mean kyphotic angle of 26.5 dgree was reduced to 18 dgree postoperatively, At the most recent follow-up, the mean kyphotic angle was 31.5 dgree in group I, a loss of correction of 13.5 dgree . In group II, the mean kyphotic angle was corrected from 27 dgrees to 13.5 dgree after surgery. At the most recent follow-up, the mean kyphotic angle was 17.5 dgrees, a loss of correction of 4 dgree . CONCLUSION: Posterior spinal instrumentation combined with conventional anterior corpectomy and anterior interbody fusion were found to be effective for preventing loss of kyphotic angle and for maintaining stable bone fusion in patients with mean
Congenital Abnormalities ; Follow-Up Studies ; Humans ; Spine ; Spondylitis* ; Transplants ; Tuberculosis, Spinal

OBJECTIVE: The zero-profile implant (Zero-P) is accepted for use in anterior cervical fusion for the treatment of degenerative cervical disease. However, evidence pertaining to its efficiency and safety in traumatic cervical injury is largely insufficient. This study aimed to compare the overall outcomes of patients who underwent Zero-P for traumatic cervical disc injury.METHODS: Data from a total of 53 consecutive patients who underwent surgery for traumatic or degenerative cervical disc disease using the Zero-P were reviewed. Seventeen patients (group A) had traumatic cervical disc injury and the remaining 36 (group B) had degenerative cervical disc herniation. The fusion and subsidence rates and Cobb angle were measured retrospectively from plain radiographs. The patients’ clinical outcomes were evaluated using the Japanese Orthopedic Association (JOA) score and Odom’s criteria.RESULTS: The C2–7 Cobb and operative segmental angles increased by 3.45±7.61 and 2.94±4.59 in group A; and 2.46±7.31 and 2.88±5.49 in group B over 12 postoperative months, respectively. The subsidence and fusion rate was 35.0% and 95.0% in group A; and 36.6% and 95.1% in group B, respectively. None of the parameters differed significantly between groups. The clinical outcomes were similar in both groups in terms of increasing the JOA score and producing a grade higher than “good” using Odom’s criteria.CONCLUSION: The application of Zero-P in patients with traumatic cervical disc injury was found to be acceptable when compared with the clinical and radiological outcomes of degenerative cervical spondylosis.
Allografts ; Asian Continental Ancestry Group ; Cervical Vertebrae ; Diskectomy ; Female ; Humans ; Orthopedics ; Retrospective Studies ; Spinal Cord Injuries ; Spondylosis

OBJECTIVE: The effects of plasma and peritoneal fluid from endometriosis patients on apoptosis of neutrophils were investigated. METHODS: Neutrophils and plasma were obtained from women with endometriosis (n=20) and healthy control donors (n=20). Peritoneal fluid from endometriosis patients (n=10) and the controls (n=5) were collected prior to laparoscopic operation. Apoptotic changes of the cells were evaluated by morphological changes using Giemsa staining. DNA electrophoretic analysis were used to confirm apoptosis. RESULTS: Compared to the plasma of healthy controls, the addition of 10% plasma from patients with endometriosis to culture medium reduced the percentage of apoptotic cells from 65.3+/-6.6 % to 27.2+/-4.6% in cultures of neutrophils maintained in vitro at 24 h. The addition of 10% peritoneal fluid obtained from patients with endometriosis to culture medium also inhibited the apoptosis of neutrophils compared with control group (10.5+/-4.3% vs. 45.3+/-4.8%). 10 ng of interleukin-8 (IL-8) in the presence of plasma from controls and endometriosis patients further delayed the spontaneous apoptosis of neutrophils. Neutralizing IL-8 antibody abrogated the delay of apoptosis of neutrophils induced by peritoneal fluid but not in the plasma of endometriosis patients. Neutrophils obtained from patients with endometriosis showed delayed apoptosis in the absence and in the presence of plasma or peritoneal fluid from either source and this delay was not abrogated by neutralizing IL-8 antibody. CONCLUSION: These findings show that IL-8 is one of the neutrophil survival factors in the peritoneal fluid of endometriosis patients, which contains both pro-apoptotic and anti-apoptotic cytokines. However, our results indicate that an unidentified survival factor is present in the plasma of patients with endometriosis, and also suggest that the impairment of innate immunity, such as the delayed apoptosis of neutrophils may be related with pathogenesis of endometriosis.
Apoptosis* ; Ascitic Fluid* ; Azure Stains ; Cytokines ; DNA ; Endometriosis* ; Female ; Fibrinogen ; Humans ; Immunity, Innate ; Interleukin-8 ; Neutrophils* ; Plasma* ; Tissue Donors

Intraosseous neurilemmoma(Schwannoma) is an extremely rare benign neoplasm. The site most commonly involved is the mandible. This occurrence is understandable because of the length of the inferior alveolar canal through the mandible. No other bone contains a canal that transmits a neurovascular bundle of such size and length. We report on a peripheral and central neurilemmoma along pathway of inferior alveolar nerve of the lower lip and mandible in a 28-year old man. A panoramic radiograph of the mandible showed a well-defined bilocular lesion with a thin uniform sclerotic margin located in the ramus and body of the mandible. The CT scan confirmed a well-defined lesion with thinning of the cortex of the body of the left side of the mandible. Histologically, the lesion was a cellular neoplasm with distinct palisading and numerous Verocay bodies. Complete excision was achieved by removing the tumor with the inferior alveolar nerve.
Adult ; Humans ; Jaw* ; Lip ; Mandible ; Mandibular Nerve ; Neurilemmoma* ; Tomography, X-Ray Computed

BACKGROUND: Electronic bulletin board systems have been used for education, information exchange, and medical consultation for a number of years. However, most of these systems have been text-based. The field of dermatology has never had a system that allowed a quick exchange of visual information. OBJECTIVE: Dermatology is a field of medicine which especially requires a visual image for an accurate diagnosis, and subsequent effective treatment. We have developed a web-based bulletin board system which can be used by any clinician with access to the internet to view clinical images of skin diseases with accompanying clinical findings. METHODS: A web-based bulletin board system was developed for the internet. The system is designed to operate independently of client hardware and software using hyper text markup language so participants using different platforms can access and use the site effectively. RESULTS: Any participant can easily upload a diagnostic image to the board along with relevant clinical information. Other participants can make comments regarding the presented case which may prove useful to the presenter in diagnosis and development of an effective treatment modality. CONCLUSION: Our web-based bulletin board system for discussion of skin diseases has the potential to help in the diagnosis and treatment of various skin diseases. Dissemination of information relating to clinical cases and participation of a widespread audience of experienced clinicians will allow better practice of dermatology and aid in further training of inexperienced clinicians.
Dermatology ; Diagnosis ; Education ; Internet ; Skin Diseases* ; Skin*