Evidence-Based Surgery

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Evidence-Based Surgery - Pillar Power

  • Evidence-Based Medicine (EBM): Integrating best research evidence, clinical expertise, and patient values.
  • Evidence-Based Surgery (EBS): Applying EBM principles to surgical practice.
  • Goals: Improve patient outcomes, standardize care, inform policy, reduce costs, guide research.
  • 📌 The 5 A's of EBS (Cyclical Process):
    • Ask: Formulate a clear, answerable clinical question.
    • Acquire: Systematically search for relevant evidence.
    • Appraise: Critically evaluate evidence for validity and usefulness.
    • Apply: Integrate appraised evidence with clinical expertise and patient values.
    • Assess/Audit: Evaluate outcomes and the EBS process itself.

⭐ The core principle of EBS is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual surgical patients.

Evidence-Based Surgery - PICO Sleuth

Formulating clinical questions: 📌 PICO framework.

  • Patient/Problem/Population: e.g., Adults with uncomplicated acute appendicitis.
  • Intervention: e.g., Laparoscopic appendectomy.
  • Comparison: e.g., Open appendectomy.
  • Outcome: e.g., ↓ Post-operative pain, ↓ length of hospital stay.

Example PICO: "In adult patients with inguinal hernia (P), is mesh repair (I) compared to non-mesh repair (C) more effective in reducing recurrence rates (O)?"

Sources of Evidence:

  • Key Databases: PubMed/MEDLINE, Cochrane Library, EMBASE.
  • Clinical Practice Guidelines (CPGs).

Basic Search Strategy:

  • Use PICO terms as keywords.
  • Combine with MeSH terms & Boolean operators (AND, OR).

⭐ A well-defined PICO question is crucial for efficient literature searching and retrieving relevant evidence.

Evidence-Based Surgery - Truth Tiers

Pyramid of Evidence-Based Medicine

  • Hierarchy of Evidence (Top Tier First):

    • Systematic Review/Meta-analysis: Pooled data. Strength: High power. Weakness: Publication bias.

      ⭐ Systematic reviews and meta-analyses of high-quality RCTs are generally considered the highest level of evidence for therapeutic interventions.

    • RCT (Randomized Controlled Trial): Random allocation. Strength: Minimizes bias. Weakness: Costly, ethics.
    • Cohort Study: Observes groups over time. Strength: Incidence, risk. Weakness: Confounding.
    • Case-Control Study: Retrospective comparison. Strength: Rare diseases. Weakness: Recall bias.
    • Case Series/Report: Descriptive. Strength: Hypothesis generation. Weakness: No control.
    • Expert Opinion: Subjective. Lowest evidence.
  • Critical Appraisal: Key aspects:

    • Validity: Sound design, bias control.
    • Reliability: Consistent results.
    • Applicability: Generalizable to patient.
  • Common Surgical Biases:

    • Selection Bias: Non-random patient choice.
    • Performance Bias: Unequal care provided.
    • Detection Bias: Biased outcome assessment.
    • Attrition Bias: Differential dropout during follow-up.

Evidence-Based Surgery - Number Logic

  • Relative Risk (RR): Riskexposed / Riskunexposed. RR<1: ↓risk with intervention.
  • Odds Ratio (OR): Oddsexposed / Oddsunexposed. OR<1: ↓odds of event with intervention.
  • Absolute Risk Reduction (ARR): Riskcontrol - Risktreatment. True difference in risk.
  • Relative Risk Reduction (RRR): ARR / Riskcontrol. Proportion of baseline risk removed by therapy.
  • Number Needed to Treat (NNT): $NNT = 1/ARR$. Fewer patients treated for one to benefit is better.
  • Number Needed to Harm (NNH): $NNH = 1/ARI$ (Absolute Risk Increase). More patients treated before one is harmed is better.
  • Confidence Intervals (CI): Range of plausible values. 95% CI significant if it excludes 1 (for RR/OR) or 0 (for ARR/differences).
  • p-value: Probability of observing effect by chance. Statistical significance typically if $p < extbf{0.05}$. Relative Risk, Odds Ratio, NNT Comparison Table
  • Integration: EBS = Best Evidence + Clinical Expertise + Patient Values.
  • Barriers: Lack of time, critical appraisal skills, resource access.

⭐ The Number Needed to Treat (NNT) is a highly intuitive measure for clinical decision-making, representing the number of patients one needs to treat with a specific intervention to prevent one additional adverse outcome.

High‑Yield Points - ⚡ Biggest Takeaways

  • Evidence-Based Surgery (EBS) integrates best research evidence, clinical expertise, and patient values.
  • PICO (Patient, Intervention, Comparison, Outcome) guides clinical question formulation.
  • Systematic Reviews & Meta-analyses of RCTs provide the highest level of evidence.
  • Randomized Controlled Trials (RCTs) are gold standard for evaluating interventions.
  • Critical appraisal assesses validity and applicability of research findings.
  • The GRADE system is used for assessing evidence quality and strength of recommendations.
  • EBS aims to improve patient outcomes and reduce practice variations in surgery.
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Practice Questions: Evidence-Based Surgery

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Which of the following is not considered a type of subject bias?

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Flashcards: Evidence-Based Surgery

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_____ is used in the closure of sternotomy wound.

TAP TO REVEAL ANSWER

_____ is used in the closure of sternotomy wound.

Surgical steel

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