Minimally Invasive Surgery - MU

• A 40-year-old female with symptomatic gallstones is preparing for a laparoscopic cholecystectomy as an elective procedure.
• Preoperative preparation and possible intra- and postoperative complications need consideration.

Definition of Minimally Invasive Surgery

• Minimally invasive surgery is a result of modern technology and surgical innovation, aiming to achieve surgical goals with reduced physical and psychological impact.
• It involves procedures through smaller incisions or orifices compared to traditional surgery.

History of Minimal Access Surgery

• Kelling performed the first experimental laparoscopic procedure in 1901.
• Jacobaeus performed the first thoracoscopy in 1910 using a cystoscope.
• Steptoe developed laparoscopy for infertility treatment in the UK 70 years later.
• Mouret carried out the first video-laparoscopic cholecystectomy in 1987.

Minimal Access Approaches

• Laparoscopy
• Thoracoscopy
• Single-incision minimal access surgery (SILS)
• Endoluminal endoscopy and natural orifice surgery
• Perivisceral endoscopy
• Arthroscopy and intra-articular joint surgery
• Hybrid minimal access surgery uses flexible/straight stick endoscopic or open/endoscopic surgery combinations.

Surgical Trauma

• Surgical trauma can occur in both open and laparoscopic surgeries.

Surgical Trauma in Open Surgeries

• Trauma in open procedures occurs due to the large wound required for adequate exposure and dissection.
• Wound complications include infection, dehiscence, bleeding, herniation, and nerve entrapment.
• Wound pain prolongs recovery and reduces mobility, increasing the risk of pulmonary atelectasis, chest infection, paralytic ileus, and DVT.

Surgical Trauma in Laparoscopic Surgeries

• During laparoscopy, low-pressure pneumoperitoneum provides retraction, applying diffuse force gently and evenly, minimizing trauma.
• Post-surgical adhesions are reduced due to less damage to serosal coverings.

Advantages of Minimal Access Surgery

• Less trauma to tissue
  • Smaller wounds and no damage from retractors.
  • Less post-operative pain, leading to increased mobility, improved respiration, and reduced need for analgesia.
  • Reduced post-operative lethargy/mental debilitation.
  • Decreased cooling and drying of the bowel, which can reduce intestinal function and threaten anastomosis, especially in the elderly and children.
  • Less Retraction and handling reduces iatrogenic injury, tissue compression, and perfusion issues.
  • Fewer adhesions and wound complications like infection and hernia formation.
  • Reduced risk of hepatitis B and AIDS transmission.
  • Improved cosmesis.
  • Better views available on monitors for teaching.
  • Short hospital stay and quicker return to normal activities.

Preparation for Minimal Access Surgery

• Overall fitness assessment: cardiac arrhythmia, lung function, medications, allergies.
• Review of previous surgeries or interventions for scars and adhesions.
• Evaluation of body habitus for obesity or skeletal deformity.
• Assessment of normal coagulation and thromboprophylaxis needs.
• Informed patient consent.
• Prediction of operative difficulty using a risk model.
• Ensuring appropriate theater time and facilities, especially for robotic cases.

Contraindications to Laparoscopy

• Patient refusal or unsuitability for general anesthesia (GA).
• Uncontrollable hemorrhagic shock.
• Surgical inexperience and gross ascites.
• Increased risks include gross obesity, pregnancy, prior abdominal surgeries with adhesions, organomegaly, abdominal aortic aneurysm, peritonitis, bowel distension, and bleeding disorders.
• Conditions once deemed contraindications can now be managed safely with experienced surgeons.

Equipment for Minimal Access Surgery

All laparoscopic procedures require:

• Imaging system (video monitor, light source, camera system)
• Insufflation device to inflate the abdominal cavity.
• Insufflation Gas:
  • Perfect gas for insufflation during laparoscopy must have limited systemic absorption, limited effects once absorbed, rapid removal, non-combustibility, high solubility in blood, and limited physiological effects.
  • Gases Used:
    • Air had historical importance but is poorly insoluble in blood and more painful.
    • CO2 is inert and rapidly absorbed, but can cause respiratory acidosis.
    • N2O is inert, less painful, and reduces intraoperative end-tidal CO2, but has a danger of combustion and is unsafe in pregnancy.
• CO2 is commonly used
• Helium is a rarely used alternative
• Intra-abdominal pressure is set to 12-15 mm Hg during laparoscopy.
• Energy source and other specialized instruments are also needed.

Principles for Minimal Access Surgery

• Establishing Pneumoperitoneum: open (Hassan) or closed (Verress) methods.
  • Open method is preferred by the Royal College of Surgeons (Eng)
  • Closed method is safe in experienced hands

Physiological Consequences of Pneumoperitoneum

• Laparoscopic surgery induces multiple physiological responses due to patient positioning and the mechanical effects of elevated intra-abdominal pressure.
• Positioning the patient to extreme positions changes physiology.
• Elevated intra-abdominal pressure reduces venous return.
• Results in absorption of CO2 and biochemical changes.

Hemodynamic Changes Due to CO2 Insufflation:

• Systemic vascular resistance (SVR) and mean arterial pressure (MAP) increases.
• Intracranial pressure (ICP) increases.
• Minimal alteration in heart rate (HR).
• Renal blood flow (RBF), portal blood flow, and splanchnic blood flow decreases.
• Pulmonary compliance decreases.
• Hypercapnia and acidosis can decrease myocardial contractility.
• Reverse Trendelenburg posture reduces LV preload and left ventricular ejection fraction (LVEF).
• Hypercapnia and pneumoperitoneum stimulate the sympathetic nervous system and catecholamine release.

Placement and Closure of Laparoscopic Ports

• Basic principles for port placement:
  • Use as few ports as possible, positioning them to allow triangulation of instruments at the operating site.
• Closure of Laparoscopic Port Sites:
  • 10-mm ports are closed in layers, including the rectus sheath and linea alba, using slowly absorbable or non-absorbable interrupted sutures to prevent port-site hernias.

Limitations of Minimal Access Surgery

• Lack of 3D vision and tactile feedback.
• Hemostasis issues.
• Extraction limitation with the size of specimens.
• Learning curve and increased operative time.
• Cost and risk of iatrogenic injuries to other organs, like the common bile duct during cholecystectomy.
• Reliance on new technologies.
• Impracticality due to adhesions or contraindications.

Operative Problems

• Intraoperative perforation of a viscus or vascular injury.
• Bleeding from organs or trocar sites.
• Evacuation of clot.
• Conversion to open surgery.
• Port site hernia.

Future Technology

• Single-incision laparoscopic surgery.
• Robotized laparoscopic instruments and robotic surgery.
• 3D imaging and augmented reality.