Surgical Principles: Minimally Invasive Surgery (MIS)

Methods

Laparoscopic

  • 4-Degrees of Motion
    • Up-Down
    • Forward-Back
    • Right-Left
    • Grip
  • 2-Dimensional View

Robotic

  • 7-Degrees of Motion
    • 4-Degrees of Laparoscopic (Up-Down, Forward-Back, Right-Left & Grip)
    • Wrist Yaw
    • Wrist Pitch
    • Wrist Roll
  • 3-Dimensional View
  • Eliminates Hand Tremor
  • Disadvantages: Longer Set Up & Higher Cost
  • Best Indications: Foregut and Deep Pelvic Surgery

Trocar Placement

Access Techniques

  • Veress Needle
    • Closed Technique
    • Spring Loaded Needle to Obtain Pneumoperitoneum for Primary Trocar
  • Hasson Technique
    • Open Cutdown & Direct Visualization for Primary Trocar
    • No Difference in Complication Rate

Placement

  • Avoid Previous Surgical Sites (Scarring and Adhesions)
  • Macrobracing: Use Nondominant Hand to Brace, Prevents Bowel Injury
  • Palmer’s Technique
    • Palmer’s Point: 3 cm Below Left Subcostal Margin
    • Access Point When Umbilical Adhesions are Present
    • Avoid in Hepatosplenomegaly
  • Pneumoperitoneum Flow Rate:
    • Always Start with Low Flow
    • Stretching Peritoneum Too Abruptly Can Cause Significant Vagal Response
    • Initial Pressure < 8 mmHg with Low Flow (1 L/min) Indicates Peritoneal Entry
    • Traditional Intraabdominal Pressure Goals: 12-15 mmHg

Pneumoperitoneum Physiologic Changes

Hemodynamics

  • IVC Compression Causes Decrease Preload & Cardiac Output
  • Increased Afterload/SVR
  • Changes Offset (HR & MAP Unchanged)
  • Can Tamponade Small Vessel Bleeding Which May Bleed when Released

Pulmonary

  • Decreased Functional Residual Capacity (FRC) – May Manifest as Elevated Peak Airway Pressure
  • CO2 Absorbed Causes Hypercarbia (Increased End Tidal CO2)
  • Increased Abdominal Pressure Causes Increased Dead Space
  • Decreased Lung Volumes (Vital Capacity, Tidal Volume & Total Volume)

Renal Effects

  • Decreased Urine Output from Increased ADH
  • BUN/Cr will Decrease in Immediate Postoperative Period

Contraindications

Laparoscopy Contraindications

  • Unable to Tolerate Pneumoperitoneum (Advanced CHF, etc.)
  • Massive Bowel Dilation
  • Refractory Coagulopathy
  • Trauma with Hemodynamic Instability
  • Gross Contamination/Peritonitis
  • Relative:
    • Extensive Previous Abdominal Surgery with Multiple Incisional Scars
    • Laparotomy within the Last 30 Days
    • Morbid Obesity
    • Cirrhosis with Portal Hypertension

Robotic Contraindications

  • Same as Laparoscopic Surgery
  • Multi-Quadrant Surgery

MIS Specific Complications

Causes of Excessive Pressure

  • Cannula Tip Displacement
  • Tubing Occlusion
  • Stopcock Turned Off
  • Light Sedation

Bowel Injury

  • Incidence: 0.13%
  • Risk Factors:
    • Surgeon Inexperience
    • Obesity
    • Prior Abdominal Surgery
    • Adhesions
  • Sites:
    • Small Bowel (56%) – Most Common
    • Large Bowel (39%)
    • Stomach (4%)
  • Causes:
    • Access Injury During Port Insertion (Veress Needle or Trocar)
      • Most Common Cause
    • Instrument Injury from Handling of Bowel
    • Thermal Injury from Equipment Failure or Improper Use
      • May Have Delayed Presentation
    • Most Common Cause in Robotics: Poor Instrument Exchanges by Assistant
  • Techniques to Avoid:
    • Avoid Previous Scars & Adhesions
      • Consider Alternate Primary Trocar Site (Palmer’s Point)
    • Macrobracing
    • Avoid Blunt Dissection – Other Than for Mild Adhesions
    • Avoid Monopolar Devices as Appropriate
  • Tx: Repair (Laparoscopic or Convert to Open)
    • < 50% Circumference: Primary Repair
    • > 50% Circumference: Resection

Insufflation Vagal Response

  • Sx: Bradycardia & Hypotension
  • Tx: Desufflation

Capnothorax (Carbon Dioxide Pneumothorax)

  • CO2 Traverses Diaphragm into Pleural Space
  • Risk Factors:
    • High Pressure
    • Prolonged Surgery (> 200 Minutes)
  • Tx: Desufflation
    • Resolves Spontaneous within Minutes to Hours
      • Chest Tube Not Needed
    • Emergent Decompression if Causing Tension Pneumothorax

CO2 Embolus

  • Sx: Sudden Drop in ETCO2 & BP
    • “Mill-Wheel” Murmur
  • Tx:
    • Desufflation
    • Positioning (Trendelenburg & Left Lateral Decubitus)
    • Aspirate Through CVC

Large Bleeding/Hemorrhage

  • Convert to Open

MIS in Pregnancy

  • Laparoscopy NOT Contraindicated in Pregnancy
  • Risks by Trimester:
    • First: Spontaneous Abortion
    • Second: Safest
    • Third: Premature Labor
  • May Require Altered Port Placement Depending on Procedure