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Oral Surgery, Oral Medicine, Oral... Nov 1997This article highlights some basic principles of the design and use of statistical tests, using a minimum of mathematics or statistical jargon. It is not the intent to... (Review)
Review
This article highlights some basic principles of the design and use of statistical tests, using a minimum of mathematics or statistical jargon. It is not the intent to summarize all the possible details involved with performing these tests, but instead to offer insight into evaluating the statistical methods found in published articles. Historically, the number of scientific articles published in which inappropriate statistical analyses were performed is alarming. Only when the reader understands the problem and demands change will this situation improve. The consequence of inaction is to be mired with an array of poorly designed articles that, at the very least, do not advance the field of study and, at worse, may influence practitioners not well versed in statistics to expose patients to useless, unnecessary, or even harmful procedures.
Topics: Analysis of Variance; Bias; Data Collection; Double-Blind Method; Goals; Humans; Probability; Random Allocation; Research Design; Single-Blind Method; Statistics as Topic
PubMed: 9394388
DOI: 10.1016/s1079-2104(97)90272-9 -
The Surgical Clinics of North America Apr 1990To evaluate the various nonshunting treatment modalities currently being used, it is difficult to make comparative assessments by reviewing the literature. There is... (Meta-Analysis)
Meta-Analysis
To evaluate the various nonshunting treatment modalities currently being used, it is difficult to make comparative assessments by reviewing the literature. There is varied composition in the groups studied; numerous major modifications, but more often subtle but poorly described differences in surgical techniques; and lack of uniform definitions and methods of reporting even the most basic of results, be it recurrent hemorrhage, encephalopathy, or survival. Series often lump together patients with cirrhosis, both alcoholic and nonalcoholic, noncirrhotic intrahepatic block, and extrahepatic block, each of which has a different natural history, prognosis, and physiologic and hemodynamic response to interventions. Classification of severity of cirrhosis, although commonly referred to as Child's class A, B, or C, may be based on time of assessment, worst criteria present, or a point scoring system. The operations are described as "emergency," "urgent," "emergent," or "elective," and the definition of each varies with investigator. Clearly, the ability of the patient to stop bleeding and survive the hazards and high mortality of the early hours of the acute event places him in a better risk group irrespective of whether the surgical intervention is performed "urgently" within 24 hours or electively in 24 days. Expressions of long-term survival frequently do not always take into account the operative deaths or the mean follow-up time. However, some general remarks can be made. The Sugiura procedure can be performed with an extremely low mortality in selected elective patients, particularly the nonalcoholic, with virtually no postoperative encephalopathy and negligible variceal rebleeding. Postoperative major hepatic decompensation does not appear to occur with time, and long-term survival would appear superior to DSR shunt. In the class A or B alcoholic cirrhotic, results are certainly as good as and perhaps better than DSR shunt, and it is a reasonable alternative, particularly when technical and other considerations make the performance of such a shunt difficult. Surgeons who routinely perform the Warren shunt should have this operation available in their repertoire as an alternative. Attempts to compromise and reduce the extent of devascularization utilizing only a thoracic or abdominal venue or to violate Sugiura's principle of leaving intact the coronary-periesophageal-azygos venous pathway generally result in a progressively higher incidence of recurrent hemorrhage with time. The early success reported by Perecchia, Abouna, and Franco, with a transabdominal approach and lesser thoracic devascularization, which avoids "entry" into the chest, is noted with interest for the future and suggests such an approach for the more critically bleeding patients rather than the initial thoracic approach of others.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Esophageal and Gastric Varices; Gastrointestinal Hemorrhage; Humans; Meta-Analysis as Topic; Methods
PubMed: 2138824
DOI: 10.1016/s0039-6109(16)45090-5 -
BMC Medical Research Methodology Dec 2017Randomization is considered to be a key feature to protect against bias in randomized clinical trials. Randomization induces comparability with respect to known and...
BACKGROUND
Randomization is considered to be a key feature to protect against bias in randomized clinical trials. Randomization induces comparability with respect to known and unknown covariates, mitigates selection bias, and provides a basis for inference. Although various randomization procedures have been proposed, no single procedure performs uniformly best. In the design phase of a clinical trial, the scientist has to decide which randomization procedure to use, taking into account the practical setting of the trial with respect to the potential of bias. Less emphasis has been placed on this important design decision than on analysis, and less support has been available to guide the scientist in making this decision.
METHODS
We propose a framework that weights the properties of the randomization procedure with respect to practical needs of the research question to be answered by the clinical trial. In particular, the framework assesses the impact of chronological and selection bias on the probability of a type I error. The framework is applied to a case study with a 2-arm parallel group, single center randomized clinical trial with continuous endpoint, with no-interim analysis, 1:1 allocation and no adaptation in the randomization process.
RESULTS
In so doing, we derive scientific arguments for the selection of an appropriate randomization procedure and develop a template which is illustrated in parallel by a case study. Possible extensions are discussed.
CONCLUSION
The proposed ERDO framework guides the investigator through a template for the choice of a randomization procedure, and provides easy to use tools for the assessment. The barriers for the thorough reporting and assessment of randomization procedures could be further reduced in the future when regulators and pharmaceutical companies employ similar, standardized frameworks for the choice of a randomization procedure.
Topics: Algorithms; Humans; Random Allocation; Randomized Controlled Trials as Topic; Selection Bias
PubMed: 29202708
DOI: 10.1186/s12874-017-0428-z -
Instructional Course Lectures 2003There has been much recent enthusiasm regarding complete arthroscopic rotator cuff repair, and it is becoming apparent that, for many, this newer technique may be a... (Review)
Review
There has been much recent enthusiasm regarding complete arthroscopic rotator cuff repair, and it is becoming apparent that, for many, this newer technique may be a preferable alternative to the more traditional mini-open rotator cuff repair. Several short-term studies have demonstrated that complete arthroscopic repair has excellent results comparable with those of mini-open repair, which is also an excellent technique. The choice of which procedure may be better for an individual patient or surgeon can be based on a variety of considerations, including the patient's expectations, the pathoanatomy of the cuff, and the surgical experience of the surgeon. The relative merits and disadvantages of arthroscopic rotator cuff repair are discussed on the basis of those considerations. When a surgeon is deciding which procedure to perform, it is important that the basic principles of rotator cuff repair not be compromised and that he or she perform the procedure that is most reproducible given his or her level of experience; however, for those who are now utilizing miniopen repair, arthroscopic repair may have important advantages and may be worth pursuing in the future. If a surgeon chooses to obtain the skills necessary to perform a complete arthroscopic repair, performance of the mini-open procedure offers an excellent opportunity to make an orderly transition.
Topics: Arthroscopy; Decision Making; Humans; Minimally Invasive Surgical Procedures; Patient Selection; Rotator Cuff; Rotator Cuff Injuries; Suture Techniques
PubMed: 12690842
DOI: No ID Found -
Medical Education Feb 2011the motor behaviours or 'actions' that provide the basis for precision limb control, including the performance of complex medical procedures, are represented at... (Review)
Review
OBJECTIVES
the motor behaviours or 'actions' that provide the basis for precision limb control, including the performance of complex medical procedures, are represented at different levels in the central nervous system. This review focuses on how these representations influence the way people perceive, execute and learn goal-directed movements.
PERCEPTION AND ATTENTION
the neural processes associated with paying attention to an object are part and particle of the same processes engaged to physically interact with that object. The automatic way in which specific actions are engaged makes it important that we structure perceptual motor environments in a manner that facilitates goal actions and minimises the likelihood of unwanted actions.
MOTOR CONTROL
most actions are organised to optimise speed, accuracy and energy expenditure while avoiding worst-case outcomes. To achieve a good outcome on movements, the performer must have the opportunity to experiment with the way specific actions are executed. Early in the discovery process, errors are necessary if the performer is to determine his or her performance boundaries. motor learning: as learning progresses, representations of action become predictive. For example, if rapid corrective processes are to operate, the performer needs to anticipate sensorimotor consequences of movement. Thus, practice should be specific to the conditions under which actions are performed, and the performer. Although nothing can replace physical practice, complex representations of action can develop by observing both expert performers and learners. In many cases, practice scenarios that include both physical practice and observations of other learners can be the most efficient use of time and resources.
CONCLUSIONS
although most of the experiments reviewed here involved laboratory tasks such as rapid aiming and movement sequencing, the majority of the principles apply to motor control and learning in more complex situations. Thus, they should be considered when developing methods to train medical personnel to perform perceptual motor procedures with precision.
Topics: Animals; Attention; Education, Medical; Energy Metabolism; General Surgery; Humans; Learning; Motor Skills; Movement
PubMed: 21166837
DOI: 10.1111/j.1365-2923.2010.03851.x -
Medical Problems of Performing Artists Dec 2022It is widely believed that posture and balance stressors are factors in playing-related pain for musicians using hand-held musical instruments. This purpose of this... (Review)
Review
It is widely believed that posture and balance stressors are factors in playing-related pain for musicians using hand-held musical instruments. This purpose of this scoping review was to assess the available literature relative to the effects of posture and balance in musicians with neuromusculoskeletal injuries. A search of Medline, Web of Science, and SportDiscus seeking articles combining posture and balance considerations with pain in performing artists was performed. From 1,403 articles initially identified by the search parameters, the further abstract/title review for relevance and inclusiveness of pain and posture/balance variables in performing artists resulted in the retention of 29 articles for this full-text scoping review. The full-text analysis assessed publication type, study design, participant population, methodology, statistical methods, main results, and whether the study evaluated the relationship between posture/balance and pain in musicians. Overall, most of the studies including musicians were observational or descriptive. Although, in recent years, there has been an increase in the number of interventional studies regarding posture, balance and pain in musicians, there is still minimal evidence about the contribution of posture and balance characteristics to pain in musician performers. To reliably establish a predictable relationship with injury symptomatology experienced by musicians, it is essential to integrate standardized, validated measurements of posture and balance in the evaluation of all musicians who report to a health professional with neuromusculoskeletal pain. This will not only allow researchers to determine the effect of postural righting dysfunction on neuromusculoskeletal injuries in musicians, but also may provide a foundation for clinicians to develop effective interventions.
Topics: Humans; Musculoskeletal Pain; Posture; Postural Balance; Upper Extremity; Research Design
PubMed: 36455112
DOI: 10.21091/mppa.2022.4032 -
European Journal of Vascular and... Feb 2011To identify and analyse existing evidence from published studies evaluating the efficacy and safety of a percutaneous vessel closure device for the closure of large... (Meta-Analysis)
Meta-Analysis Review
A systematic literature review of the efficacy and safety of the Prostar XL device for the closure of large femoral arterial access sites in patients undergoing percutaneous endovascular aortic procedures.
OBJECTIVES
To identify and analyse existing evidence from published studies evaluating the efficacy and safety of a percutaneous vessel closure device for the closure of large arterial femoral arterial access sites (≥ 10 French).
DESIGN
This study was a systematic literature review and meta-analysis.
MATERIALS AND METHODS
Electronic databases were searched for studies published on the evaluation of the Prostar XL vessel closure device. There was no restriction by study design or patient population. Appraisal of studies for inclusion and data extraction were performed independently by two reviewers. Meta-analysis was performed where feasible.
RESULTS
Twenty-one studies were included, which reported data specifically for closure of large (≥ 10 Fr) femoral arterial access sites using the Prostar XL device. The Prostar XL device, used for closure of these large femoral artery access sites, had a high rate of procedural success equal to that reported for closure by femoral artery surgical cut-down. There was evidence for reduced procedural time, time to discharge and time to ambulation. Complication rates were lower, but not significantly so, with Prostar XL vs. surgical cut-down.
CONCLUSIONS
The Prostar XL is an effective and safe device for use in percutaneous closure of large (≥ 10 Fr) femoral artery access sites, comparable to open surgical femoral artery cut-down. Furthermore, it may reduce procedure times and hospitalisations, thereby leading to potential cost savings.
Topics: Aortic Diseases; Endovascular Procedures; Femoral Artery; Hemorrhage; Hemostatic Techniques; Humans; Patient Selection; Punctures; Risk Assessment; Treatment Outcome
PubMed: 21144777
DOI: 10.1016/j.ejvs.2010.10.015 -
International Journal of Technology... 2000We reviewed and appraised the methods by which the issue of the learning curve has been addressed during health technology assessment in the past. (Review)
Review
OBJECTIVE
We reviewed and appraised the methods by which the issue of the learning curve has been addressed during health technology assessment in the past.
METHOD
We performed a systematic review of papers in clinical databases (BIOSIS, CINAHL, Cochrane Library, EMBASE, HealthSTAR, MEDLINE, Science Citation Index, and Social Science Citation Index) using the search term "learning curve."
RESULTS
The clinical search retrieved 4,571 abstracts for assessment, of which 559 (12%) published articles were eligible for review. Of these, 272 were judged to have formally assessed a learning curve. The procedures assessed were minimal access (51%), other surgical (41%), and diagnostic (8%). The majority of the studies were case series (95%). Some 47% of studies addressed only individual operator performance and 52% addressed institutional performance. The data were collected prospectively in 40%, retrospectively in 26%, and the method was unclear for 31%. The statistical methods used were simple graphs (44%), splitting the data chronologically and performing a t test or chi-squared test (60%), curve fitting (12%), and other model fitting (5%).
CONCLUSIONS
Learning curves are rarely considered formally in health technology assessment. Where they are, the reporting of the studies and the statistical methods used are weak. As a minimum, reporting of learning should include the number and experience of the operators and a detailed description of data collection. Improved statistical methods would enhance the assessment of health technologies that require learning.
Topics: Biomedical Technology; Clinical Competence; Diffusion of Innovation; Humans; Learning; Research Design; Statistics as Topic; Technology Assessment, Biomedical
PubMed: 11155830
DOI: 10.1017/s0266462300103149 -
The AAPS Journal Jul 2023Comparison of two analytical procedures is the primary objective of a method transfer or when replacing an old procedure with a new one in a single lab. Guidance for...
Comparison of two analytical procedures is the primary objective of a method transfer or when replacing an old procedure with a new one in a single lab. Guidance for comparing two analytical procedures is provided in USP <1010> based on separate tests for accuracy and precision. Determination of criteria is somewhat problematic for these comparisons because of the interdependence of accuracy and precision. In this paper, a total error approach is proposed that requires a single criterion based on an allowable out-of-specification (OOS) rate at the receiving lab. This approach overcomes the difficulty of allocating acceptance criteria between precision and bias. Computations can be performed with any simulation software. Numerical examples are provided for four experimental designs that are typical in a method transfer study. Finally, recommendations are provided to help the user set criteria that provide an acceptable probability of passing for practical sample sizes.
Topics: Reproducibility of Results; Research Design; Sample Size; Computer Simulation; Probability
PubMed: 37468665
DOI: 10.1208/s12248-023-00834-1 -
Brain Research. Brain Research Reviews Jun 2003Recent data demonstrate that the cerebellum contributes to the internal representation of action. This representation is used not only to generate motor actions, but... (Review)
Review
Recent data demonstrate that the cerebellum contributes to the internal representation of action. This representation is used not only to generate motor actions, but also to understand and learn the actions and skills of others by imitation. The cerebellar networks appear to be indispensable for acquiring complex behaviors and procedures. The cerebellar role in the acquisition of procedural competencies is particularly evident in spatial information processing. The cerebellum allows acquiring by observation competencies in exploration behaviors as efficient as the competencies acquired by actually performing the same task. The specificity of the cerebellar role in the acquisition phases of learning by observation is demonstrated by the complete absence of spatial learning when the observational training is performed in presence of a cerebellar lesion. This datum is further corroborated by the evidence that, once acquired, spatial procedures can be efficiently performed even in the presence of cerebellar damage, in agreement with the neuroimaging findings of low cerebellar activation after prolonged practice. The finding that the cerebellum is involved in procedural acquisition and in observational learning allowed us to dissect a complex behavior into single behavioral units forming a complete procedural sequence, demonstrating that such behavioral units do exist and can be independently acquired.
Topics: Animals; Cerebellum; Exploratory Behavior; Humans; Learning; Motor Activity; Nerve Net; Observation
PubMed: 12791443
DOI: 10.1016/s0165-0173(03)00176-0