Definition & Concept

• Laparoscopic (minimal access) surgery accomplishes surgical goals with minimal somatic and psychological trauma
• A rigid endoscope is introduced through a port (trocar) into the peritoneal cavity
• The operative field is visualized on a video monitor rather than by direct vision
• First laparoscopic procedure: Kelling, 1901; first video-laparoscopic cholecystectomy: Mouret, 1987

1. Pneumoperitoneum - Creating the Working Space

• The abdominal wall must be lifted away from abdominal organs to create a working space
• Two methods:
  • Gas insufflation (pneumoperitoneum) - used by most surgeons
  • Mechanical abdominal wall lifting (gasless laparoscopy) - less common

Gas used:

• CO2 (carbon dioxide) - most widely used
  • Rapidly absorbed across the peritoneal membrane
  • Non-combustible - safe with electrosurgery
  • Rapidly cleared by the lungs
• N2O (nitrous oxide) - used in some cases; better analgesia under local anaesthesia; safety in cancer surgery not established
• Air - historically used; poorly soluble, absorbed slowly; now avoided

Pneumoperitoneum pressure:

• Standard working pressure: 12-15 mmHg
• In thoracoscopy (if needed): 5-8 mmHg
• Higher pressures impair venous return and diaphragmatic movement

2. Physiological Effects of CO2 Pneumoperitoneum

Gas-specific effects:

• CO2 absorbed across peritoneal membrane → enters circulation
• Forms carbonic acid → respiratory acidosis
• Body buffers (mainly bone) absorb up to 120 L CO2
• Once buffers saturated → hypercarbia develops rapidly
• Anaesthesiologist compensates by increasing ventilatory rate or tidal volume
• Can cause cardiac arrhythmias if severe acidosis develops
• Causes tachycardia and increased systemic vascular resistance

Pressure-specific effects:

• Elevated intra-abdominal pressure reduces venous return (IVC compression)
• Reduces cardiac output
• Diaphragm elevation → decreased functional residual capacity
• Can worsen renal perfusion at high pressures
• Promotes DVT risk (venous stasis in lower limbs)

3. Abdominal Access Techniques

Closed technique (Veress needle):

• A Veress needle is inserted blindly (usually at the umbilicus) to insufflate CO2
• Correct placement confirmed by:
  • Saline drop test (fluid drops in freely)
  • Low initial insufflation pressure (<10 mmHg)
  • Uniform abdominal distension
• Primary trocar then inserted after pneumoperitoneum established

Open (Hasson) technique:

• A small skin incision is made and peritoneum opened under direct vision
• Hasson cannula is inserted and secured with sutures
• Safer in patients with previous abdominal surgery (adhesions)
• Reduces risk of vascular or bowel injury on entry

Optical trocar technique:

• Trocar with a transparent tip is inserted while watching through a zero-degree scope
• Allows layer-by-layer entry under vision

4. Trocar Placement Principles

• Primary (camera) port - usually at the umbilicus
• Working ports - placed to allow triangulation around the target organ
• Triangulation principle: camera at apex; two instrument ports form the base of a triangle around the operative field
• The camera should be opposite the operative site, at adequate distance for full visualization
• Port placement must avoid:
  • Inferior epigastric vessels (lateral ports)
  • Intercostal vessels (thoracoscopic ports)
  • Previous scars (adhesions beneath)

5. Optics and Vision

• 0° telescope - straight-forward view; used for most abdominal procedures
• 30° telescope - angled view; allows wider field; preferred in pelvic and upper abdominal surgery
• 2D vision - standard laparoscopy; loss of depth perception
• 3D vision - available with newer systems; improves depth perception and precision
• Light is transmitted via fibre-optic cables from a cold light source
• Camera is connected to a video processor and displayed on a high-definition monitor

6. Instrumentation Principles

• Instruments are longer than open surgery counterparts (typically 30-45 cm)
• Movement through trocars follows the fulcrum effect: movement at the tip is opposite to the surgeon's hand movement
• Instruments have limited degrees of freedom compared to the human hand (conventional laparoscopy: 4 DOF)
• Graspers, dissectors, scissors, clip appliers, staplers, suturing devices all have laparoscopic equivalents
• Suction-irrigation is essential for maintaining a clear field

7. Electrosurgery in Laparoscopy

• Monopolar diathermy - most commonly used; current passes from instrument tip through patient to a grounding pad
  • Risk: capacitive coupling and insulation failure causing burns to adjacent bowel
• Bipolar diathermy - current passes only between the two jaws of the instrument; safer for delicate structures
• Ultrasonic (harmonic) devices - use high-frequency vibration to cut and coagulate; no electrical current through patient; minimal lateral thermal spread
• Vessel sealing devices (e.g., LigaSure) - seal vessels up to 7 mm diameter reliably

8. Ergonomics and Patient Positioning

• Surgeon stands facing the monitor, which should be in line with the operative site
• Patient positioning uses gravity to displace bowel away from the operative field:
  • Trendelenburg (head-down) - for pelvic surgery (bowel falls towards diaphragm)
  • Reverse Trendelenburg (head-up) - for upper abdominal surgery (bowel falls into pelvis)
  • Lateral tilt - to displace bowel to one side
• Pneumoperitoneum retraction is diffuse, gentle, and even - less traumatic than mechanical retractors

9. Advantages of Laparoscopic Surgery

• Smaller incisions → less wound pain
• Reduced wound complications: infection, dehiscence, herniation, nerve entrapment
• Faster recovery and shorter hospital stay
• Less handling of bowel → less ileus, less adhesion formation
• Less heat and fluid loss from open body cavities
• Better cosmesis (smaller scars)
• Improved visualization in some areas (pelvis, deep structures)
• Reduced immune/stress response compared to open surgery

10. Limitations of Laparoscopic Surgery

• Loss of depth perception (2D vision in standard laparoscopy)
• Fulcrum effect - counterintuitive instrument movement
• Loss of tactile (haptic) feedback - cannot feel tissue texture or tension
• Longer learning curve for surgeons
• Restricted instrument movement - limited degrees of freedom
• Longer operating times in complex procedures
• Higher direct costs (instruments, equipment)
• CO2 physiology - not suitable for all patients (severe COPD, cardiac disease)

11. Contraindications

• Absolute: uncorrected coagulopathy, inability to tolerate general anaesthesia
• Relative:
  • Severe COPD or ischaemic heart disease (CO2 intolerance)
  • Extensive previous abdominal surgery (dense adhesions)
  • Bowel distension (reduces working space)
  • Haemodynamic instability in trauma

12. Complications

• Entry injuries: bowel, major vessel (aorta, IVC) injury - most serious
• Trocar site bleeding: inferior epigastric vessel injury
• Gas embolism: CO2 entering a vessel - rare but life-threatening
• Surgical emphysema: CO2 tracking into subcutaneous tissues
• Port site hernia: especially at ports ≥10 mm (fascial closure required)
• Port site metastasis: seeding of tumour cells at trocar sites in cancer surgery

Sources: Bailey and Love's Short Practice of Surgery, 28th Ed. | Schwartz's Principles of Surgery, 11th Ed.