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The prevalence of obesity is increasing, resulting in an increase in the number of surgeries performed to treat obesity and diseases induced by obesity. The associated comorbidities as well as the pharmacokinetic and pharmacodynamic changes that occur in obese patients make it difficult to control the appropriate dose of anesthetic agents. Factors that affect pharmacokinetic changes include the increase in adipose tissue, lean body weight, extracellular fluid, and cardiac output associated with obesity. These physiological and body compositional changes cause changes in the pharmacokinetic and pharmacodynamic parameters. The increased central volume of distribution and alterations in the clearance of drugs affect the plasma concentration of propofol and remifentanil in the obese population. Additionally, obesity can affect pharmacodynamic properties, such as the 50% of maximal effective concentration and the effect-site equilibration rate constant (ke0). Conducting a simulation of target-controlled infusions based on pharmacokinetic and pharmacodynamic models that include patients that are obese can help clinicians better understand the pharmacokinetic and pharmacodynamic changes of anesthetic drugs associated with this population.
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General medical journals such as the Korean Journal of Anesthesiology (KJA) receive numerous manuscripts every year. However, reviewers have noticed that the tables presented in various manuscripts have great diversity in their appearance, resulting in difficulties in the review and publication process. It might be due to the lack of clear written instructions regarding reporting of statistical results for authors. Therefore, the present article aims to briefly outline reporting methods for several table types, which are commonly used to present statistical results. We hope this article will serve as a guideline for reviewers as well as for authors, who wish to submit a manuscript to the KJA.
ABSTRACT
General medical journals such as the Korean Journal of Anesthesiology (KJA) receive numerous manuscripts every year. However, reviewers have noticed that the tables presented in various manuscripts have great diversity in their appearance, resulting in difficulties in the review and publication process. It might be due to the lack of clear written instructions regarding reporting of statistical results for authors. Therefore, the present article aims to briefly outline reporting methods for several table types, which are commonly used to present statistical results. We hope this article will serve as a guideline for reviewers as well as for authors, who wish to submit a manuscript to the KJA.
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Purpose@#The aim of this article was to highlight various terminologies and methods of calculation of minimal clinically important difference (MCID) and summarize MCID values of frequently used patient-reported outcome measures (PROMs) evaluating total knee arthroplasty (TKA). @*Materials and methods@#PubMed and EMBASE databases were searched through May 2019. Of 71 articles identified, 18 articles matched and underwent a comprehensive analysis for terminologies used to indicate clinical significance, method of calculation, and reported MCID values. @*Results@#MCID was the most common terminology (67% studies) and anchor-based methods were most commonly employed (67% studies) to calculate it. The analytical methods used to calculate and the estimated values of MCID for clinical use are highly variable. MCID values reported for WOMAC scores are 20.5 to 36.0, 17.6 to 33.0 and 12.9 to 25.0 for pain, function and stiffness sub-scales, respectively, and 4.7 to 10.0 for OKS. @*Conclusion@#There was lack of standardization in the methodology employed to calculate MCID in the available studies. MCID values reported in this review could be used for patients undergoing TKA, although caution is advised in their interpretation and application.
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Properly set sample size is one of the important factors for scientific and persuasive research. The sample size that can guarantee both clinically significant differences and adequate power in the phenomena of interest to the investigator, without causing excessive financial or medical considerations, will always be the object of concern. In this paper, we reviewed the essential factors for sample size calculation. We described the primary endpoints that are the main concern of the study and the basis for calculating sample size, the statistics used to analyze the primary endpoints, type I error and power, the effect size and the rationale. It also included a method of calculating the adjusted sample size considering the dropout rate inevitably occurring during the research. Finally, examples regarding sample size calculation that are appropriately and incorrectly described in the published papers are presented with explanations.
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Background@#Surgical treatment consisting of decompression and fusion is generally known to produce good clinical results for lumbar spinal stenosis with degenerative spondylolisthesis. However, the clinical outcome of decompression alone, without fusion, remains unclear, and long-term follow-up results are scarce. This study aimed to retrospectively analyze the 5-year clinical results of decompression only in patients with lumbar spinal stenosis and degenerative spondylolisthesis. @*Methods@#Among the patients diagnosed as having lumbar spinal stenosis with degenerative spondylolisthesis, 36 patients who underwent decompression without fusion and were followed up for minimum 5 years were included in this study. The average follow-up period was 7.2 years, and the mean age of patients was 63.2 years. Visual analog scale (VAS) score and Oswestry disability index (ODI) were investigated pre- and postoperatively, and also radiologic displacement and instability were measured. In addition, patients who needed fusion or redecompression at the decompression site postoperatively were also investigated. @*Results@#VAS score and ODI improved from an average of 7.8 points and 57 points preoperatively, respectively, to 1.4 points and 19 points at 5 years postoperatively, respectively. The degree of radiologic displacement increased from an average of 5.1 mm preoperatively to 6.4 mm at the final follow-up. Radiological instability was detected in five patients. Two patients (9.5%) required fusion. @*Conclusions@#The long-term follow-up results revealed that satisfactory clinical outcomes were obtained with decompression alone, without fusion, for patients with lumbar spinal stenosis and degenerative spondylolisthesis.
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Objectives@#The purpose of this study was to analyze several factors affecting the efficacy of epidural steroid injections as a nonoperative treatment modality in lumbar disc herniation patients.Summary of Literature Review: Despite several studies, the normal course of intervertebral disc herniation is not fully understood, and the optimal timing of surgery is unclear. @*Methods@#From January 2017 to April 2019, among outpatients in our hospital, 64 patients diagnosed with 3-4 or 4-5 single-level lumbar disc herniation and followed up for at least 6 weeks were included. Epidural steroid injection was performed in all patients during their 1-week admission. Symptoms improved in 36 patients (group 1) and persisted or recurred in 28 patients (group 2), who were finally treated surgically. Demographic factors, magnetic resonance imaging findings, and clinical assessments were analyzed. @*Results@#The only demographic factor with a significant difference between groups was symptom duration. In magnetic resonance imaging, significant differences were found in disc sequestration and the degree of the herniated disc. At 6 weeks after the injection, significant differences were found between the 2 groups in visual analog scale scores and the Korean version of the Oswestry Disability Index. @*Conclusions@#Several factors must be considered when treating patients with lumbar disc herniation. Of note, longer symptom duration was found to be associated with a lower effectiveness of conservative treatment. The effects of treatment could also be influenced by the disc form and the degree of disc herniation.
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Objectives@#The purpose of this study was to analyze several factors affecting the efficacy of epidural steroid injections as a nonoperative treatment modality in lumbar disc herniation patients.Summary of Literature Review: Despite several studies, the normal course of intervertebral disc herniation is not fully understood, and the optimal timing of surgery is unclear. @*Methods@#From January 2017 to April 2019, among outpatients in our hospital, 64 patients diagnosed with 3-4 or 4-5 single-level lumbar disc herniation and followed up for at least 6 weeks were included. Epidural steroid injection was performed in all patients during their 1-week admission. Symptoms improved in 36 patients (group 1) and persisted or recurred in 28 patients (group 2), who were finally treated surgically. Demographic factors, magnetic resonance imaging findings, and clinical assessments were analyzed. @*Results@#The only demographic factor with a significant difference between groups was symptom duration. In magnetic resonance imaging, significant differences were found in disc sequestration and the degree of the herniated disc. At 6 weeks after the injection, significant differences were found between the 2 groups in visual analog scale scores and the Korean version of the Oswestry Disability Index. @*Conclusions@#Several factors must be considered when treating patients with lumbar disc herniation. Of note, longer symptom duration was found to be associated with a lower effectiveness of conservative treatment. The effects of treatment could also be influenced by the disc form and the degree of disc herniation.
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PURPOSE@#This paper compares the clinical outcomes of patients who were treated with a cervical nerve block by ultrasound and C-arm and reports the complication.@*MATERIALS AND METHODS@#A total of 97 patients were treated with an ultrasound-guided nerve root block from May 1, 2015 to February 8, 2018. On the other hand, 94 patients were treated with a C-arm guided nerve root block. The consequences of the cervical pain and the radiating pain before and after the procedures were reviewed using the verbal numeric rating scale (VNRS). In addition, the complications related to the procedures from the daily notes from the chart were inspected.@*RESULTS@#Sixty-six cases out of 97 cases of ultrasound-guided nerve root block were enrolled in the study. The average age of the patients was 57 years, including 41 males and 25 females. Seventy seven out of 94 cases by a C-arm guided root block were included in the study. The average age of the patients was 55 years, including 40 males and 37 females. Before the nerve root block, the mean numeric rating pain scale (NRS) of the cervical pain in ultrasound-guided block decreased from 5.4 points to 2.7 points at three weeks and 1.4 points at six weeks (p=0.0023, p<0.001), and 3.1 points in the C-arm (p<0.001, p<0.001) at three weeks and 1.5 points at six weeks (p<0.001, p<0.001). In the case of radiating pain, the mean NRS in the ultrasound-guided nerve root block group improved from 6.3 points after the procedure to 2.8 points at three weeks and 1.5 points at six weeks (p<0.001, p<0.001). In the C-arm guided nerve root block group, the NRS improved from 7.4 points after the procedure to 3.3 points at three weeks and 1.9 points at six weeks. In the case of complications, Horner's syndrome and propriospinal myoclonus were observed in one case of C-arm guided block group.@*CONCLUSION@#The clinical results of the patients who underwent ultrasound-guided cervical nerve root block were not significantly different from those who underwent a C-arm guided cervical nerve root block.
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Most parametric tests start with the basic assumption on the distribution of populations. The conditions required to conduct the t-test include the measured values in ratio scale or interval scale, simple random extraction, normal distribution of data, appropriate sample size, and homogeneity of variance. The normality test is a kind of hypothesis test which has Type I and II errors, similar to the other hypothesis tests. It means that the sample size must influence the power of the normality test and its reliability. It is hard to find an established sample size for satisfying the power of the normality test. In the current article, the relationships between normality, power, and sample size were discussed. As the sample size decreased in the normality test, sufficient power was not guaranteed even with the same significance level. In the independent t-test, the change in power according to sample size and sample size ratio between groups was observed. When the sample size of one group was fixed and that of another group increased, power increased to some extent. However, it was not more efficient than increasing the sample sizes of both groups equally. To ensure the power in the normality test, sufficient sample size is required. The power is maximized when the sample size ratio between two groups is 1 : 1.
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In a large number of randomized controlled trials, researchers provide P values for demographic data, which are commonly reported in table 1 of the article for the purpose of emphasizing the lack of differences between or among groups. As such, the authors intend to demonstrate that statistically insignificant P values in the demographic data confirm that group randomization was adequately performed. However, statistically insignificant P values do not necessarily reflect successful randomization. It is more important to rigorously establish a plan for statistical analysis during the design and planning stage of the study, and to consider whether any of the variables included in the demographic data could potentially affect the research results. If a researcher rigorously designed and planned a study, and performed it accordingly, the conclusions drawn from the results would not be influenced by P values, regardless of whether they were significant. In contrasts, imbalanced variables could affect the results after variance controlling, even though whole study process are well planned and executed. In this situation, the researcher can provide results with both the initial method and a second stage of analysis including such variables. Otherwise, for brief conclusions, it would be pointless to report P values in a table simply listing baseline data of the participants.
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OBJECTIVES@#This study was conducted to evaluate the effects of using an epidural steroid sponge for postoperative pain control in lumbar discectomy.SUMMARY OF LITERATURE REVIEW: There are many methods to control postoperative pain after lumbar discectomy, including opioid analgesics, epidural catheters, and epidural steroid Gelfoam sponges.@*MATERIALS AND METHODS@#A total of 72 patients who underwent surgery between March 2011 and February 2014 were enrolled. Their average age was 54 years (range, 24–82 years). In group A (35 patients), Gelfoam was inserted after being soaked with a solution of 2% lidocaine (400 mg/20 mL; 1 vial) and dexamethasone (5 mg/mL; 1 ampoule). In group B (37 patients), it was inserted after soaking with normal saline. Postoperative pain was assessed by visual analogue scale (VAS) scores. Pain above 5 points was controlled by a narcotic analgesic agent, and the duration and number of postoperative interventions, the period of time before walking after the operation, and the period until the date of discharge after surgery were assessed and compared. The Mann-Whitney U test was used as a nonparametric method. P-values less than 0.05 were considered to indicate statistical significance.@*RESULTS@#In group A, 15 patients did not require analgesics on the day of surgery. In 20 patients, no analgesics were needed on postoperative day (POD) 1. In group B, 8 patients on the day of surgery and 13 patients on POD 1 did not require analgesics. In group A, 26 patients were able to walk on the day of surgery, and all patients were able to walk on POD 1. In group B, 19 patients was able to walk on the day of surgery and all patients were able to walk on POD 1. The mean number of hospital days before discharge was 6.3 in group A and 8.2 in group B.@*CONCLUSIONS@#By continuously releasing low doses of steroids into the epidural space, this technique provided satisfactory results for postoperative pain control.
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STUDY DESIGN: Retrospective study. OBJECTIVES: This study was conducted to evaluate the effects of using an epidural steroid sponge for postoperative pain control in lumbar discectomy. SUMMARY OF LITERATURE REVIEW: There are many methods to control postoperative pain after lumbar discectomy, including opioid analgesics, epidural catheters, and epidural steroid Gelfoam sponges. MATERIALS AND METHODS: A total of 72 patients who underwent surgery between March 2011 and February 2014 were enrolled. Their average age was 54 years (range, 24–82 years). In group A (35 patients), Gelfoam was inserted after being soaked with a solution of 2% lidocaine (400 mg/20 mL; 1 vial) and dexamethasone (5 mg/mL; 1 ampoule). In group B (37 patients), it was inserted after soaking with normal saline. Postoperative pain was assessed by visual analogue scale (VAS) scores. Pain above 5 points was controlled by a narcotic analgesic agent, and the duration and number of postoperative interventions, the period of time before walking after the operation, and the period until the date of discharge after surgery were assessed and compared. The Mann-Whitney U test was used as a nonparametric method. P-values less than 0.05 were considered to indicate statistical significance. RESULTS: In group A, 15 patients did not require analgesics on the day of surgery. In 20 patients, no analgesics were needed on postoperative day (POD) 1. In group B, 8 patients on the day of surgery and 13 patients on POD 1 did not require analgesics. In group A, 26 patients were able to walk on the day of surgery, and all patients were able to walk on POD 1. In group B, 19 patients was able to walk on the day of surgery and all patients were able to walk on POD 1. The mean number of hospital days before discharge was 6.3 in group A and 8.2 in group B. CONCLUSIONS: By continuously releasing low doses of steroids into the epidural space, this technique provided satisfactory results for postoperative pain control.
Subject(s)
Humans , Analgesia, Epidural , Analgesics , Analgesics, Opioid , Catheters , Dexamethasone , Diskectomy , Epidural Space , Gelatin Sponge, Absorbable , Lidocaine , Methods , Pain, Postoperative , Porifera , Retrospective Studies , Steroids , WalkingABSTRACT
There are some errors in the published article. The authors would like to make corrections in the original version of the article.
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BACKGROUND: It is uncommon for patients who have received a permanent implant to remove the spinal cord stimulator (SCS) after discontinuation of medication in complex regional pain syndrome (CRPS) due to their completely painless state. This study evaluated CRPS patients who successfully removed their SCSs. METHODS: This 10-year retrospective study was performed on patients who had received the permanent implantation of an SCS and had removed it 6 months after discontinuation of stimulation, while halting all medications for neuropathic pain. Age, sex, duration of implantation, site and type of CRPS, and their return to work were compared between the removal and non-removal groups. RESULTS: Five (12.5%, M/F = 4/1) of 40 patients (M/F = 33/7) successfully removed the permanent implant. The mean age was younger in the removal group (27.2 ± 6.4 vs. 43.5 ± 10.7 years, P < 0.01). The mean duration of implantation in the removal group was 34.4 ± 18.2 months. Two of 15 patients (13.3%) and 3 of 25 patients (12%) who had upper and lower extremity pain, respectively, had removed the implant. The implants could be removed in 5 of 27 patients (18.5%) with CRPS type 1 (P < 0.01). All 5 patients (100%) who removed their SCS returned to work, while only 5 of 35 (14.3%) in the non-removal group did (P < 0.01). CONCLUSIONS: Even though this study had limited data, younger patients with CRPS type 1 could remove their SCSs within a 5-year period and return to work with complete pain relief.
Subject(s)
Humans , Age Factors , Device Removal , Extremities , Lower Extremity , Neuralgia , Retrospective Studies , Return to Work , Spinal Cord Stimulation , Spinal CordABSTRACT
Most parametric tests start with the basic assumption on the distribution of populations. The conditions required to conduct the t-test include the measured values in ratio scale or interval scale, simple random extraction, normal distribution of data, appropriate sample size, and homogeneity of variance. The normality test is a kind of hypothesis test which has Type I and II errors, similar to the other hypothesis tests. It means that the sample size must influence the power of the normality test and its reliability. It is hard to find an established sample size for satisfying the power of the normality test. In the current article, the relationships between normality, power, and sample size were discussed. As the sample size decreased in the normality test, sufficient power was not guaranteed even with the same significance level. In the independent t-test, the change in power according to sample size and sample size ratio between groups was observed. When the sample size of one group was fixed and that of another group increased, power increased to some extent. However, it was not more efficient than increasing the sample sizes of both groups equally. To ensure the power in the normality test, sufficient sample size is required. The power is maximized when the sample size ratio between two groups is 1 : 1.
Subject(s)
Biostatistics , Normal Distribution , Sample SizeABSTRACT
In a large number of randomized controlled trials, researchers provide P values for demographic data, which are commonly reported in table 1 of the article for the purpose of emphasizing the lack of differences between or among groups. As such, the authors intend to demonstrate that statistically insignificant P values in the demographic data confirm that group randomization was adequately performed. However, statistically insignificant P values do not necessarily reflect successful randomization. It is more important to rigorously establish a plan for statistical analysis during the design and planning stage of the study, and to consider whether any of the variables included in the demographic data could potentially affect the research results. If a researcher rigorously designed and planned a study, and performed it accordingly, the conclusions drawn from the results would not be influenced by P values, regardless of whether they were significant. In contrasts, imbalanced variables could affect the results after variance controlling, even though whole study process are well planned and executed. In this situation, the researcher can provide results with both the initial method and a second stage of analysis including such variables. Otherwise, for brief conclusions, it would be pointless to report P values in a table simply listing baseline data of the participants.
Subject(s)
Bias , Methods , Random AllocationABSTRACT
Stem cells are attracting attention as a key element in future medicine, satisfying the desire to live a healthier life with the possibility that they can regenerate tissue damaged or degenerated by disease or aging. Stem cells are defined as undifferentiated cells that have the ability to replicate and differentiate themselves into various tissues cells. Stem cells, commonly encountered in clinical or preclinical stages, are largely classified into embryonic, adult, and induced pluripotent stem cells. Recently, stem cell transplantation has been frequently applied to the treatment of pain as an alternative or promising approach for the treatment of severe osteoarthritis, neuropathic pain, and intractable musculoskeletal pain which do not respond to conventional medicine. The main idea of applying stem cells to neuropathic pain is based on the ability of stem cells to release neurotrophic factors, along with providing a cellular source for replacing the injured neural cells, making them ideal candidates for modulating and possibly reversing intractable neuropathic pain. Even though various differentiation capacities of stem cells are reported, there is not enough knowledge and technique to control the differentiation into desired tissues in vivo. Even though the use of stem cells is still in the very early stages of clinical use and raises complicated ethical problems, the future of stem cells therapies is very bright with the help of accumulating evidence and technology.
Subject(s)
Adult , Humans , Adult Stem Cells , Aging , Cell Differentiation , Embryonic Stem Cells , Induced Pluripotent Stem Cells , Musculoskeletal Pain , Nerve Growth Factors , Neuralgia , Osteoarthritis , Stem Cell Transplantation , Stem CellsABSTRACT
BACKGROUND: Primary spontaneous pneumothorax (PSP) affects patients without clinically apparent lung disorder found in tall and thin young male. Scoliosis refers to curves exceeding 10° Cobb angle observed through chest X-ray and affects 2% to 4% of adolescents. Both conditions are commonly encountered in primary health care setting. The aim of this study is to access the correlation of thoracic scoliosis and PSP in adolescent. METHODS: A retrospective analysis was conducted for patients diagnosed for PSP in Konyang University Hospital between January 2010 and March 2017. Chest X-rays of 222 patients and 155 normal control (NC) cases were reviewed to measure the Cobb angle. Greater than 10° of Cobb angle is diagnosed as scoliosis. RESULTS: Scoliosis in patient with PSP has higher incidence than that of NC group (p < 0.001). Median value of Cobb angle is 12.9° in PSP group and 14.7° in NC group. Directional relationship between scoliosis and pneumothorax in PSP group is also observed; 40.5% cases are ipsilateral and 59.5% are contralateral. CONCLUSION: PSP patients tend to have thoracic scoliosis more commonly compared with normal healthy adolescent. Scoliosis may contribute to heterogeneity of alveolar pressure which exacerbates subpleural bleb formation that can cause pneumothorax. The causal relationship is unclear and further studies are needed in the future.
Subject(s)
Adolescent , Humans , Male , Blister , Incidence , Lung , Pneumothorax , Population Characteristics , Primary Health Care , Retrospective Studies , Scoliosis , ThoraxABSTRACT
PURPOSE: Recently, a method of forming a slot in the prosthesis lingual has been introduced to solve the occlusal and aesthetic disadvantages of screw-retained prosthesis in the manufacture of implant-fixed prosthesis and to ensure retrievability in cement retained prostheses. The purpose of this study is to investigate the effect of the internal gap on the removal of the prosthesis in the preparation of cement-retained implant prostheses with lingual slots. MATERIALS AND METHODS: Titanium abutment and internal gap of the zirconia prosthesis to be attached to the upper part were set to 30, 35, and 50 µm, respectively. Three for each type total 15 were produced for each type. The zirconia prosthesis formed a retrievable cement-type slot with a space of 1 mm at the location where the titanium abutment meets the shelf area. Autocatalytic resin cement was used for bonding of abutment and zirconia prosthesis, and the maximum removal stress value was measured in units of Ncm by using the customized equipment of the cemented specimen. The Kruskal-Wallis test was used to compare the three groups by statistical analysis (α = .05), modified by post hoc test the Mann-Whitney U-test and the Bonferroni correction method were used to compare the two methods (α = .017). RESULTS: There was no statistically significant difference in removal stress between the 30 µm group and the 35 µm group in the internal gap (P = .032), and there was a significant difference between the 30 µm group and the 50 µm group, between the 35 µm group and the 50 µm group (P < .017). CONCLUSION: Thus, the internal gap of computer-aided design affected the retention between the zirconia prosthesis and the titanium abutment.