Minimal Access Surgery Principles

Minimal Access Surgery Principles

Minimal Access Surgery Principles

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Minimal Access Surgery Principles - Keyhole Revolution

  • Concept: "Keyhole surgery"; utilizes small incisions, specialized instruments, and camera (laparoscope) for visualization.
  • Pioneer: Dr. Philippe Mouret (first laparoscopic cholecystectomy, 1987).
  • Core Principles:
    • Magnified 2D/3D vision on monitor.
    • Triangulation: optimal port placement for instrument maneuverability.
    • Pneumoperitoneum: insufflation of CO2 (non-combustible, high blood solubility) to create working space.
      • Standard intra-abdominal pressure: 12-15 mmHg in adults.
    • Ergonomics: surgeon and team positioning for comfort and efficiency.
  • Advantages: ↓ Post-operative pain, ↓ hospital stay, faster recovery, improved cosmesis, ↓ adhesions.
  • Disadvantages: Steep learning curve, loss of direct tactile sensation, potential for longer initial operative times, specific complications (e.g., trocar injuries, CO2 embolism, port-site hernias).

⭐ Veress needle entry: Two audible clicks often indicate correct entry into the peritoneal cavity (fascia and peritoneum). Initial pressure should be < 10 mmHg.

Minimal Access Surgery Principles - Tiny Tech Titans

  • Core Equipment:
    • Insufflator (CO₂): Maintains pneumoperitoneum (pressure 12-15 mmHg).
    • Light Source: Xenon or LED.
    • Camera System: HD/4K, Hopkins rod-lens or chip-on-tip.
    • Monitor: High resolution, ergonomic placement.
  • Instrumentation:
    • Trocars: Access ports (e.g., Hasson, optical, bladed, bladeless). Sizes 5-12 mm.
    • Hand Instruments: Graspers, dissectors, scissors, needle holders (various tips).
    • Energy Devices: Monopolar/bipolar diathermy, ultrasonic (Harmonic Scalpel), advanced bipolar (LigaSure). Laparoscopic tower setup
  • Physiological Effects: ↑ Intra-abdominal pressure → ↓ venous return, ↑ SVR, ↑ peak airway pressure.

Veress needle placement: Audible clicks (fascia, peritoneum), saline drop test, aspiration test, and low initial pressure (<8 mmHg) confirm correct placement before insufflation.

  • Key Principles: Triangulation, fulcrum effect, depth perception challenges, ergonomic instrument handling.
  • 📌 Mnemonic (CO₂ advantages): Cheap, Odorless, Non-flammable, Easily absorbed (C.O.N.E. but CO₂ is the one!)

Minimal Access Surgery Principles - Pneumo Effects & Perils

  • Physiological Effects of CO2 Pneumoperitoneum (IAP target 12-15 mmHg):
    • Cardiovascular: ↑MAP, ↑SVR, ↑HR. ↑IAP → ↓venous return, ↓CO. Hypercapnia, acidosis, arrhythmias risk.
    • Respiratory: ↓Lung compliance, ↓FRC, ↑Peak airway pressure. V/Q mismatch, atelectasis risk.
    • Renal: ↓Renal blood flow, ↓GFR, transient oliguria.
    • Cerebral: ↑ICP, especially in Trendelenburg position.
  • Potential Complications:
    • Access: Injury (vascular, visceral) from Veress needle/trocar.
    • Gas-related:
      • CO2 embolism (⚠️ sudden ↓ETCO2, hypotension, "mill-wheel" murmur).
      • Subcutaneous emphysema, pneumothorax, pneumomediastinum.
    • Positioning: Nerve injury (e.g., brachial plexus, common peroneal), compartment syndrome.
    • Other: Port-site issues (hernia, infection, metastasis), hypothermia (due to cold, dry CO2 insufflation).

⭐ > CO2 is the preferred gas for insufflation; its high solubility in blood reduces the risk and severity of gas embolism compared to air or N2O.

Trocar insertion technique

Minimal Access Surgery Principles - Access & Ergonomics

  • Access Methods:
    • Veress Needle (Closed): Blind insertion; saline drop/aspiration tests.
    • Hasson Technique (Open): Direct visualization entry; safer with prior surgery/adhesions.
  • Pneumoperitoneum:
    • Gas: CO2 (standard).
    • Pressure: 12-15 mmHg (adults).
    • Palmer's Point: Left subcostal, mid-clavicular line; alternative primary access.
  • Ergonomics & Port Setup:
    • Surgeon: Neutral posture, elbows 90-120°.
    • Monitor: Eye level, 0-15° downward gaze, opposite surgeon.
    • Ports: Triangulation principle; instrument working angles 60-90°.

Laparoscopic surgery ergonomic setup diagram

⭐ Standard insufflation pressure for CO2 pneumoperitoneum is 12-15 mmHg; exceeding this significantly increases risk of cardiopulmonary compromise and gas embolism.

High‑Yield Points - ⚡ Biggest Takeaways

  • CO2 is the preferred gas for pneumoperitoneum; typical pressure 12-15 mmHg.
  • Access techniques: Veress needle (closed) or Hasson cannula (open).
  • Physiological effects: ↑ intra-abdominal pressure, ↑ PaCO2, potential ↓ venous return.
  • Major complications: vascular injury, bowel injury, gas embolism.
  • Commonest post-op issue: shoulder tip pain (phrenic nerve irritation).
  • Advantages: ↓ post-op pain, ↓ hospital stay, better cosmesis.
  • Port-site hernia is a known late complication of laparoscopic surgery.
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Practice Questions: Minimal Access Surgery Principles

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Which of the following is NOT a CONTRAINDICATION for laparoscopic surgery:

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Flashcards: Minimal Access Surgery Principles

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In a _____ incision, the rectus abdominis muscles are transected in the middle

Hint: Maylard/Pfannenstiel

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In a _____ incision, the rectus abdominis muscles are transected in the middle

Maylard

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