The application of hyperbaric oxygen therapy in the management of compromised flaps.

INTRODUCTION: Hyperbaric oxygen (HBO2) therapy has been used to promote viability of compromised flaps despite a paucity of supportive clinical evidence. This study provides an in-depth characterization of hyperbaric medicine to promote flap survival and identifies treatment variables associated with positive clinical outcomes. METHODS: A retrospective review was conducted of patients who received HBO2 therapy for a failing or threatened post-reconstructive flap from 5/30/2008 through 4/30/2012. Medical records were reviewed to collect patient characteristics, hyperbaric oxygen therapy details, and clinical outcomes. Descriptive and comparative statistics were utilized. RESULTS: Ninety-one patients underwent HBO2 therapy during this time period, with 15 patients meeting the selection criteria. Flap survival was achieved in 11 patients (73.3%). Of those successfully treated, four (36.4%) healed completely, and seven (63.6%) demonstrated marked improvement. Patients who were treated successfully demonstrated an average improvement in flap area of 68.3%. Variables significantly associated with a favorable treatment outcome included a high percentage of treatment completion (p = 0.022) and high pretreatment transcutaneous oxygen measurements (p = 0.05). Smoking was a negative factor (p = 0.011). CONCLUSION: This study provides clinical data characterizing and supporting the application of hyperbaric medicine to aid in the viability of compromised flaps.

Sample size determination in medical and surgical research.

One of the most critical yet frequently misunderstood principles of research is sample size determination. Obtaining an inadequate sample is a serious problem that can invalidate an entire study. Without an extensive background in statistics, the seemingly simple question of selecting a sample size can become quite a daunting task. This article aims to give a researcher with no background in statistics the basic tools needed for sample size determination. After reading this article, the researcher will be aware of all the factors involved in a power analysis and will be able to work more effectively with the statistician when determining sample size. This work also reviews the power of a statistical hypothesis, as well as how to estimate the effect size of a research study. These are the two key components of sample size determination. Several examples will be considered throughout the text.

Principles of statistics in surgery.

Surgery, like any other scientific discipline, requires a systematic analysis of all its different variables in order to prove the real significance of research findings. Statistics, the science of numerical evaluation, can thoroughly help to determine the real value of surgical treatment. In this work, we study the statistical tests and principles needed to demonstrate their role in surgical research. Without a strong statistical background, a researcher may feel overwhelmed when deciding what statistical methods to utilize in research. Determining what type of data to collect and what hypothesis test to run can alter the entire way a surgical study is conducted. The relationship between power, sample size and effect size is discussed as well as the components necessary for a power analysis. Selecting an appropriate sample size is of utmost importance in any type of research since an undersized sample can invalidate an entire study. Categorical surgical data, numerical data, and the appropriate statistical procedures needed for analysis are reviewed. Methods discussed include the 2-Sample t-test, Mann Whitney U test, Kruskal-Wallis, ANOVA, Chi-Square test and Fisher's exact test.