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

The purpose of the study is to investigate the changes of the blood aqueous barrier, the flow rate and IOP after cyclocryotherapy in the white rabbits. After cyclocryotherapy we injected intravenously a dose of 25mg/kg of fluorescein sodium and sampled the aqueous humor at 1 and 2 hour and measured the concentration of flouorescein sodium by means of HPLC(High Performance Liquid Chromatography). By the comparision study among the control group, 4 times cyclocryotherapy application group and 8 times cyclocryotherapy applications group during experimental period, the results were summarized as follows. 1. In the control group, the mean aqueous amount was 0.297+0.020ml, the flow rate was 3.282+0.426 ul/min. 2. In the cyclocryotherapy group, IOP was significantly decreased during experimental period. It was found that the IOP in the 8 times cyclocryotherapy application group was more decreased than that in the times cyclocryotherapy application group after 2 weeks. 3. There was marked increase of the concentration of fluorescein sodium in aqueous humour after acute cyclocryotherapy, but it was decreased to normal level at 4 weeks. The difference between the two groups was not found. 4. The flow rate was markedly decreased after acute cycrocryotherapy and was almost back to normal 4 weeks in two groups. There was difference between the two groups. 5. In Electron microscopic study, many wide intercellular gaps between the nonpigmented and pigmented epithelium are observed but the nucleus of the nonpigmented and pigmented epithelium are well preserved on the day of experiment. From 7 days the nucleus, and both nonpigmented and pigmented epithelium are markedly decreased in number. By 28 days the cytoplasm is shrunken, nucleus has disappeared, and a capillary near pig-ment epithelium obstructed but the basement membrane of thest cells is well pres-erved. 6. After cyclocryotherapy, The IOP decreased progressively during experimental period, but the flow rate was almost back to normal at 4 weeks. From the result we can deduce the outflow facility was not influenced by cyclocryotherapy. And so it was suggested from electron microscopic study that IOP lowering effect of cyclocryotherapy was due to quantitiative destruction of aqueous production.
Aqueous Humor ; Basement Membrane ; Blood-Aqueous Barrier* ; Capillaries ; Cytoplasm ; Epithelium ; Fluorescein ; Rabbits* ; Sodium

BACKGROUND: Persistent auras after temporal lobectomy may be bothersome to the patients even though they are seizure free. But most authors specifically are concerned about the seizure outcome itself. The aim of the present study was to investigate which factors are related to persistent auras in patients with temporal lobe epilepsy(TLE) after temporal lobectomy. METHODS: We have retrospectively analysed many factors in 38 TLE patients with aura. All patients underwent anterior temporal lobectomy with amygdalo-hippocampectomy. Twenty three patients were seizure and aura free (completely seizure-free) and 15 patients had persistent auras(persistent auras) in spite of seizure-free. Characteristics of auras, past medical history, presence of secondary GTC, seizure frequency, age of surgery, age of onset, duration of habitual seizure, ictal EEG pattern, and pre- and postoperative MRI findings were compared between group with completely seizure-free and group with persistent aura. RESULTS: Characteristics of aura, past medical history, presence of secondary GTC, seizure frequency, ictal EEG pattern, age of onset, and age of surgery had no statistical differences between both groups. Seizure duration of group with persistent aura seemed to be longer than that of group with completely seizure-free(13.6 years vs 17.0 years, median test, p=0.10) and remained hippocampus in postsurgical MRI seemed to be related to persistent auras(Fisher's exact test, p=0.06). CONCLUSIONS: We found that there were suggestive differences in seizure duration and remained hippocampus between the two groups.
Age of Onset ; Anterior Temporal Lobectomy ; Electroencephalography ; Epilepsy* ; Epilepsy, Temporal Lobe ; Hippocampus ; Humans ; Magnetic Resonance Imaging ; Prognosis ; Retrospective Studies ; Seizures ; Temporal Lobe

BACKGROUND: Telemedicine can be useful in dermatology in which there is a physical barrier between the dermatologist and patient or primary care giver. OBJECTIVE: Our purpose of this study is to examine a usefulness of teledermatology system in Korean situation. METHODS: We made store-and forward teledermatology system on world wide web for it's usefulness. We examined the difference of diagnostic accuracy, level of certainty, and quality of images of photographs and still digital images. RESULTS: The merits of our teledermatology system are summarized as follows1. It has more diagnostic accuracy than classic store-and forward system. 2. The real-time additional history taking and request of laboratory examinations are possible by chatting system between dermatologist and primary care giver. 3. Patient follow-up is easier than store-and forward system. The difference of diagnostic accuracy, level of certainty, and quality of images of photographs and still digital images are summarized as follows. 1. There is no difference of diagnostic accuracy between photographic readers and digital image readers. 2. There is no difference of level of certainty between photographic readers and digital image readers. 3. In assesment of quality of photographs, no difference was founded between photographic readers and digital image readers 4. The satisfaction of quality of photographs is very high in all groups. The average is 97.5%. CONCLUSION: This study provides evidence that our teledermatology system is useful in korean situation and still digital image can substitute historic photographs in teledermatology.
Dermatology* ; Equidae ; Follow-Up Studies ; Humans ; Internet ; Primary Health Care ; Telemedicine*