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International Journal of Oral and... May 2014Bone resorption following tooth loss often interferes with dental implant placement in a desired position, and requires additional bone augmentation procedures. Many... (Review)
Review
Bone resorption following tooth loss often interferes with dental implant placement in a desired position, and requires additional bone augmentation procedures. Many techniques have been described to augment and reconstruct alveolar ridge width and height. The aim of this study was to systemically review whether there is evidence to provide indications for the various bone augmentation procedures based on defect dimension and type. An electronic search of the Medline database and Cochrane library, complemented by a manual search, was performed. Inclusion criteria for partial edentulism were: clinical trials on bone augmentation procedures in preparation or at the time of implant placement, reporting preoperative and postoperative dimensions of the ridge. For edentulous patients, studies were included when providing the data on ridge and defect description, or the amount of augmentation achieved. The search yielded 53 publications for partially edentulous patients and 15 publications for edentulous patients. The literature provides evidence that dehiscence and fenestrations can be treated successfully with guided bone regeneration (GBR) at the time of implant placement (mean implant survival rate (MISR) 92.2%, mean complication rate (MCR) 4.99%). In partially edentulous ridges, when a horizontal defect is present, procedures such as staged GBR (MISR 100%, MCR 11.9%), bone block grafts (MISR 98.4%, MCR 6.3%), and ridge expansion/splitting (MISR 97.4%, MCR 6.8%) have proved to be effective. Vertical defects can be treated with simultaneous and staged GBR (MISR 98.9%, MCR 13.1% and MISR 100%, MCR 6.95%, respectively), bone block grafts (MISR 96.3%, MCR 8.1%), and distraction osteogenesis (MISR 98.2%, MCR 22.4%). In edentulous patients, there is evidence that bone block grafts can be used (MISR 87.75%), and that Le Fort I osteotomies can be applied (MISR 87.9%), but associated with a high complication rate. The objective of extracting specific indications for each procedure could not be fully achieved due to the heterogeneity of the studies available. Further studies on bone augmentation procedures should report precise preoperative and postoperative measurements to enable a more exact analysis of the augmentation procedure, as well as to provide the clinician with the rationale for choosing the most indicated surgical approach.
Topics: Alveolar Ridge Augmentation; Dental Implantation, Endosseous; Humans; Patient Selection
PubMed: 24451333
DOI: 10.1016/j.ijom.2013.12.004 -
Surgery Jan 2011In the initial phases of surgical training, attentional resources are monopolized by the execution of novel tasks. This consideration can result in overwhelming... (Comparative Study)
Comparative Study Randomized Controlled Trial
BACKGROUND
In the initial phases of surgical training, attentional resources are monopolized by the execution of novel tasks. This consideration can result in overwhelming attentional resources, leaving few for other tasks. Practicing a technical task decreases the attentional resources required for its execution. These resources are then free for redistribution to other, clinically important tasks. This pilot study investigated how laboratory-based surgical training on a technical procedure affects concurrent acquisition of other, nontechnical information.
METHODS
After watching an instructional video, 16 first-year surgical residents performed a pyloroplasty procedure and were divided randomly so half received 6 trials of hands-on practice of the procedure (practice group) whereas the other did not (no practice). After 1 week, participants returned to perform the procedure on 2 tests: isolated procedural performance (transfer) and concurrent procedural and listening performance (dual). Procedural and listening performances were compared between groups using expert measures of performance (Global Rating Scale [GRS], task-specific checklist, and number of errors) and written test scores.
RESULTS
GRS and error scores reflected greater practice group performance on both tests: transfer test (P < .05 for all measures) and dual test (GRS, P < .05; error, P < .001). Most important, the practice group also retained more clinical information, indicated by higher written test scores (P < .001).
CONCLUSION
Findings in this study suggest that practice outside of the operating room may result in a decrease in attentional resources dedicated to technical task execution, thus facilitating trainees' ability to distribute attentional resources between concurrent, clinically important task performances.
Topics: Adult; Attention; Clinical Competence; Confidence Intervals; Education, Medical, Graduate; Educational Measurement; Female; General Surgery; Humans; Internship and Residency; Learning; Male; Observation; Ontario; Pilot Projects; Pylorus; Reference Values; Task Performance and Analysis; Video Recording
PubMed: 20430409
DOI: 10.1016/j.surg.2010.03.006 -
Instructional Course Lectures 2004The decision of what procedure to perform for the treatment of monocompartmental osteoarthritis of the knee when nonsurgical treatment methods fail remains... (Comparative Study)
Comparative Study Review
Different surgical options for monocompartmental osteoarthritis of the knee: high tibial osteotomy versus unicompartmental knee arthroplasty versus total knee arthroplasty: indications, techniques, results, and controversies.
The decision of what procedure to perform for the treatment of monocompartmental osteoarthritis of the knee when nonsurgical treatment methods fail remains controversial. Recent advances using osteotomy, unicompartmental knee replacement, and total knee replacement have been reported. For example, there are new concepts for performing high tibial osteotomies rather than the traditional Coventry method. Many techniques now involve osteotomies below the tibial tubercle. Unicompartmental knee replacement can be done using a standard approach, but less invasive approaches exist, along with minimally invasive approaches for total knee replacement, rather than the standard large incision, that promote decreased soft-tissue destruction.
Topics: Arthroplasty, Replacement, Knee; Biomechanical Phenomena; Humans; Joint Deformities, Acquired; Minimally Invasive Surgical Procedures; Osteoarthritis, Knee; Osteotomy; Patient Selection; Tibia; Treatment Outcome
PubMed: 15116621
DOI: No ID Found -
Psychosomatic Medicine 2015The need for appropriate multiple comparisons correction when performing statistical inference is not a new problem. However, it has come to the forefront in many new... (Comparative Study)
Comparative Study
OBJECTIVE
The need for appropriate multiple comparisons correction when performing statistical inference is not a new problem. However, it has come to the forefront in many new modern data-intensive disciplines. For example, researchers in areas such as imaging and genetics are routinely required to simultaneously perform thousands of statistical tests. Ignoring this multiplicity can cause severe problems with false positives, thereby introducing nonreproducible results into the literature.
METHODS
This article serves as an introduction to hypothesis testing and multiple comparisons for practical research applications, with a particular focus on its use in the analysis of functional magnetic resonance imaging data.
RESULTS
We discuss hypothesis testing and a variety of principled techniques for correcting for multiple tests. We also illustrate potential pitfalls problems that can occur if the multiple comparisons issue is not dealt with properly. We conclude, by discussing effect size estimation, an issue often linked with the multiple comparisons problem.
CONCLUSIONS
Failure to properly account for multiple comparisons will ultimately lead to heightened risks for false positives and erroneous conclusions.
Topics: Data Interpretation, Statistical; False Positive Reactions; Functional Neuroimaging; Humans; Magnetic Resonance Imaging; Research Design; Sample Size; Statistics as Topic
PubMed: 25647751
DOI: 10.1097/PSY.0000000000000148 -
Research Synthesis Methods May 2021Methods for indirect comparisons and network meta-analysis use aggregate level data from multiple studies. A very common, and closely related, scenario is where a... (Meta-Analysis)
Meta-Analysis
Methods for indirect comparisons and network meta-analysis use aggregate level data from multiple studies. A very common, and closely related, scenario is where a company has individual patient data (IPD) from its own trial, but only has published aggregate data from a competitor's trial, and an indirect comparison of the treatments evaluated in these two trials is required. Matching-Adjusted Indirect Comparison (MAIC) has been developed for this situation, where we use the available IPD to adjust for between-trial imbalances in the distributions of observed baseline covariates between the two trials. We extend the current MAIC methodology, where we compute the weights that satisfy the conventional method of moments and result in the largest possible effective sample size (ESS). We show that the approach proposed by Zubizarreta in a previous study can be used for this purpose. We derive a new analytical result that shows why this alternative approach provides a larger ESS than a conventional MAIC. We also derive a new formula for the maximum ESS that can be achieved, even when permitting negative weights, when adjusting for one covariate. This can be used as an easily computed new metric that quantifies the difficulty in adjusting for covariates. What is already known: MAIC is an established way to perform population adjustment in the situation where IPD is available from one trial but only aggregate level data is available from another trial, and an indirect comparison is required. However the effective sample size (ESS) can be small after making the adjustment. What is new: We show that an alternative method can result in a larger ESS. We provide new analytical results showing why this is the case. We derive a new descriptive statistic that is based on maximising the ESS that quantifies the difficulties in adjusting for particular covariates. Potential impact for RSM readers outside the authors' field: Reweighting methods for population adjustment are becoming more commonly used and their implications for research synthesis methodology is now considerable. This paper provides important new links between the theoretical literature, and the more applied research synthesis methodology literature, relating to this topic.
Topics: Humans; Network Meta-Analysis; Research Design; Sample Size
PubMed: 33131206
DOI: 10.1002/jrsm.1466 -
Pediatrics Mar 2009Sucrose has analgesic and calming effects in newborns. To date, it is not known whether the beneficial effects extend to caregiving procedures that are performed after... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
Sucrose has analgesic and calming effects in newborns. To date, it is not known whether the beneficial effects extend to caregiving procedures that are performed after painful procedures. Our objective was to determine the effect of sucrose analgesia for procedural pain on infant pain responses during a subsequent caregiving procedure.
PATIENTS AND METHODS
We conducted a double-blind, randomized, controlled trial. Healthy neonates within 2 strata (normal infants and infants of diabetic mothers) were randomly assigned to a sucrose or placebo water group before all needle procedures after birth. Pain response during a diaper change performed after venipuncture for the newborn screening test was determined by using a validated multidimensional measure, the Premature Infant Pain Profile.
RESULTS
The study was conducted between September 15, 2003, and July 27, 2004. Altogether, 412 parents were approached; 263 consented. Twenty-three infants were not assigned, leaving 240 for participation (n = 120 per group), with an equal number in each infant strata. Of those, 186 (78%) completed the study. There were no significant differences in birth characteristics between groups. During diaper change, sucrose-treated infants had lower pain scores than placebo-treated infants. The relative risk of having pain, defined as a Premature Infant Pain Profile score of >/=6, was 0.64 with sucrose compared with placebo.
CONCLUSIONS
This study demonstrates that when used to manage pain, sucrose reduces the pain response to a subsequent routine caregiving procedure. Therefore, the benefits of sucrose analgesia extend beyond the painful event to other aversive and potentially painful procedures.
Topics: Analgesia; Arousal; Crying; Double-Blind Method; Female; Humans; Infant Care; Infant, Newborn; Male; Neonatal Screening; Pain; Pain Measurement; Phlebotomy; Sucrose
PubMed: 19254979
DOI: 10.1542/peds.2008-3028 -
BMC Bioinformatics Oct 2023An important problem in toxicology in the context of gene expression data is the simultaneous inference of a large number of concentration-response relationships. The...
BACKGROUND
An important problem in toxicology in the context of gene expression data is the simultaneous inference of a large number of concentration-response relationships. The quality of the inference substantially depends on the choice of design of the experiments, in particular, on the set of different concentrations, at which observations are taken for the different genes under consideration. As this set has to be the same for all genes, the efficient planning of such experiments is very challenging. We address this problem by determining efficient designs for the simultaneous inference of a large number of concentration-response models. For that purpose, we both construct a D-optimality criterion for simultaneous inference and a K-means procedure which clusters the support points of the locally D-optimal designs of the individual models.
RESULTS
We show that a planning of experiments that addresses the simultaneous inference of a large number of concentration-response relationships yields a substantially more accurate statistical analysis. In particular, we compare the performance of the constructed designs to the ones of other commonly used designs in terms of D-efficiencies and in terms of the quality of the resulting model fits using a real data example dealing with valproic acid. For the quality comparison we perform an extensive simulation study.
CONCLUSIONS
The design maximizing the D-optimality criterion for simultaneous inference improves the inference of the different concentration-response relationships substantially. The design based on the K-means procedure also performs well, whereas a log-equidistant design, which was also included in the analysis, performs poorly in terms of the quality of the simultaneous inference. Based on our findings, the D-optimal design for simultaneous inference should be used for upcoming analyses dealing with high-dimensional gene expression data.
Topics: Research Design; Computer Simulation
PubMed: 37858091
DOI: 10.1186/s12859-023-05526-3 -
Journal of Visualized Experiments : JoVE Aug 2023The options for testing new cardiac procedures and investigative medical devices prior to use in an animal model are limited. In this study, we present a method for...
The options for testing new cardiac procedures and investigative medical devices prior to use in an animal model are limited. In this study, we present a method for mounting a porcine aortic valve in a pulse duplicator to evaluate its hydrodynamic properties. These properties can then be evaluated before and after the procedure under investigation is performed and/or the investigative medical device is applied. Securing the inflow segment presents some difficulty owing to the lack of circumferential myocardium in the left ventricular outflow tract. This method addresses that issue by securing the inflow segment using the anterior leaflet of the mitral valve and then suturing the left ventricular free wall around the inflow fixture. The outflow segment is secured simply by inserting the fixture into an incision in the superior aspect of the aortic arch. We found that specimens had significantly different hydrodynamic properties before and after tissue fixation. This finding induced us to use fresh specimens in our testing and should be considered when using this method. In our work, we used this method to test novel intracardiac patch materials for use in the valvular position by performing an aortic valve neocuspidization procedure (Ozaki procedure) on the mounted porcine aortic valves. These valves were tested before and after the procedure to assess the change in hydrodynamic properties in comparison to the native valve. Herein, we report a platform for hydrodynamic testing of experimental aortic valve procedures that enables comparison with the native valve and between different devices and techniques used for the procedure under investigation.
Topics: Swine; Animals; Aortic Valve; Hydrodynamics; Research Design; Catheters; Heart Rate
PubMed: 37677044
DOI: 10.3791/65885 -
Plastic and Reconstructive Surgery Apr 1996Breast reduction is a surgical procedure most commonly performed on an inpatient basis under general anesthesia. In the current climate of health care reform, we must...
Breast reduction is a surgical procedure most commonly performed on an inpatient basis under general anesthesia. In the current climate of health care reform, we must evaluate such procedures to determine if there are alternate, less expensive, but equally safe means to perform them. Our purpose is to present our experience with 50 bilateral breast reductions performed under local anesthesia with intravenous sedation between October of 1991 and October of 1994. We have excluded bilateral reductions under 500 gm total, unilateral reductions, mastopexies, and gynecomastia procedures. Patients were sedated with intravenous Versed and fentanyl and a local solution consisting of marcaine, lidocaine, and 1:2000,000 epinephrine. Intercostal blocks were not used routinely. Monitoring and sedation were performed by nonanesthesia personnel in 49 patients. There were no complications relating to the sedation or to the local solution. All reductions were performed by the inferior pedicle technique. The average patient age was 28.0 years (20 to 67 years). The total breast tissue resected was 1372 gm (516 to 2948 gm), with 33 patients having resections greater than 1000 gm. Operative times averaged 3 hours (115 to 275 minutes). Forty-nine of the 50 patients tolerated the procedure with little or no recall. Twenty-eight patients were discharged on the same day as admission. One patient recalled some significant discomfort during parts of the procedure. All stated that they would again have the procedure performed under local anesthesia with intravenous sedation. Our conclusions are as follows: (1) Breast reduction can be performed safely and comfortably under local anesthesia with intravenous sedation. (2) Patients should be chosen on their acceptability as intravenous sedation candidates and not with regard to the amount of breast tissue removed. (3) There will be a subset of patients who can be discharged on the same day.
Topics: Adult; Ambulatory Surgical Procedures; Anesthesia, Local; Anesthetics, Intravenous; Anesthetics, Local; Bupivacaine; Cost Control; Epinephrine; Female; Fentanyl; Humans; Hypnotics and Sedatives; Lidocaine; Mammaplasty; Midazolam; Patient Selection; Promethazine; Time Factors
PubMed: 8618998
DOI: 10.1097/00006534-199604001-00010 -
Statistics in Medicine Oct 2023Recent innovation in trial design to improve study efficiency has led to the development of basket trials in which a single therapeutic treatment is tested on several... (Review)
Review
Recent innovation in trial design to improve study efficiency has led to the development of basket trials in which a single therapeutic treatment is tested on several patient populations, each of which forms a basket. In a common setting, patients across all baskets share a genetic marker and as such, an assumption can be made that all patients may have a homogeneous response to treatments. Bayesian information borrowing procedures utilize this assumption to draw on information regarding the response in one basket when estimating the response rate in others. This can improve power and precision of estimates particularly in the presence of small sample sizes, however, can come at a cost of biased estimates and an inflation of error rates, bringing into question validity of trial conclusions. We review and compare the performance of several Bayesian borrowing methods, namely: the Bayesian hierarchical model (BHM), calibrated Bayesian hierarchical model (CBHM), exchangeability-nonexchangeability (EXNEX) model and a Bayesian model averaging procedure. A generalization of the CBHM is made to account for unequal sample sizes across baskets. We also propose a modification of the EXNEX model that allows for better control of a type I error. The proposed method uses a data-driven approach to account for the homogeneity of the response data, measured through Hellinger distances. Through an extensive simulation study motivated by a real basket trial, for both equal and unequal sample sizes across baskets, we show that in the presence of a basket with a heterogeneous response, unlike the other methods discussed, this model can control type I error rates to a nominal level whilst yielding improved power.
Topics: Humans; Bayes Theorem; Computer Simulation; Sample Size; Research Design
PubMed: 37614070
DOI: 10.1002/sim.9867