What Defines Minimally Invasive Surgery
Minimally invasive surgery (MIS) accomplishes procedures through small incisions using specialized instrumentation and video visualization, rather than a traditional open approach with direct hand access. Benefits typically include reduced postoperative pain, shorter hospital stays, lower infection risk, and faster recovery, though MIS requires specialized equipment, additional training, and careful patient selection.
Pneumoperitoneum and Insufflation
Most laparoscopic abdominal procedures require creating a working space by insufflating the abdominal cavity with carbon dioxide (CO2) gas, creating a pneumoperitoneum.
- Why CO2 - it is non-flammable (critical given electrosurgery use), highly soluble in blood (reducing the risk of significant gas embolism compared to air), and rapidly eliminated by the lungs.
- Typical insufflation pressure - generally maintained around 12-15 mmHg in adults, balancing adequate visualization/working space against physiologic effects of elevated intra-abdominal pressure.
- Physiologic effects - elevated intra-abdominal pressure can decrease venous return and cardiac output, elevate peak airway pressures, and cause CO2 absorption leading to hypercarbia, all of which the anesthesia provider monitors closely throughout the case.
Access to the abdominal cavity for initial insufflation is achieved via a Veress needle (a spring-loaded blunt-tip needle used to create pneumoperitoneum before the first trocar is placed) or an open (Hasson) technique, where the peritoneum is entered directly under direct vision before insufflation begins - the open technique is generally preferred in patients with prior abdominal surgery due to adhesion risk.
Trocar and Port Placement
Trocars are sharp or blunt-tipped devices that create a portal through the abdominal wall, through which a cannula (sleeve) remains in place to allow instrument exchange throughout the case while maintaining the pneumoperitoneum seal. The initial (often umbilical) port is typically used for the laparoscope/camera, with additional working ports placed under direct visualization based on the specific procedure's triangulation needs - positioning ports too close together restricts instrument movement and increases the risk of instruments clashing.
Visualization Equipment
| Component | Function |
|---|---|
| Laparoscope (telescope) | Rigid optical instrument that transmits an image from inside the body to the camera; available in 0-degree (straight-ahead) and angled (30-degree, 45-degree) configurations |
| Camera and camera control unit | Converts the optical image into an electronic signal displayed on OR monitors |
| Light source and fiber optic cable | Provides illumination inside the body cavity; high-intensity xenon or LED sources are standard |
| Insufflator | Delivers and regulates CO2 flow and pressure into the body cavity throughout the case |
| Monitors/tower | Displays the live surgical image for the entire team; positioned for optimal surgeon and assistant ergonomics |
Laparoscopic Instrumentation
Laparoscopic instruments are long-shafted versions of traditional open instruments, adapted to pass through a trocar while allowing the surgeon to manipulate tissue at a distance: graspers, scissors, dissectors, clip appliers, and specialized devices such as laparoscopic staplers and specimen retrieval bags. Many instruments are designed for energy delivery (monopolar hook, bipolar grasper, ultrasonic shears) since hemostasis at a distance requires reliable energy-based tools rather than direct manual pressure.
The Surgical Technologist's Role in MIS Setup
- Confirm all camera, light source, and insufflation equipment function properly before the patient is draped, since troubleshooting after draping wastes valuable time.
- White-balance the camera per manufacturer protocol before insertion to ensure accurate color representation on the monitor.
- Keep the laparoscope lens warm (using a warming device or antifog solution) to prevent fogging on insertion into the warm, humid body cavity.
- Organize the back table and Mayo stand to allow rapid, correctly-oriented instrument exchange, since MIS procedures often move quickly between multiple specialized tools.
- Maintain awareness of insufflator pressure and gas volume readouts throughout the case, alerting the team to any unexpected pressure changes that could indicate a leak or complication.
Conversion to Open Surgery
Any laparoscopic procedure can require conversion to an open approach due to bleeding, dense adhesions, unclear anatomy, or equipment failure. The surgical team - including the scrub person - should always be prepared with an open instrument tray immediately available, and should never assume a laparoscopic case will remain minimally invasive throughout.
Robotic-Assisted Considerations
Robotic-assisted surgery builds on standard laparoscopic principles (insufflation, trocar placement, video visualization) but adds a surgeon-controlled robotic platform; this distinction and its unique setup requirements are covered in depth in the companion topic on robotic-assisted surgery.
Why This Matters for the Exam
MIS content on the CST exam blends physics (insufflation physiology), equipment knowledge (visualization towers, energy devices), and procedural judgment (port placement rationale, conversion readiness). Approaching MIS as an integrated system - not a disconnected list of equipment names - will serve you well on both scenario-based and straightforward recall questions.