Principles of Laparoscopy- Trocar Positioning and Placement - Richard Davis
Executive Summary
Laparoscopic surgery offers significant advantages, including decreased postoperative pain and shortened recovery times. However, its implementation in resource-limited settings requires a specialized approach to equipment and technique. Successful laparoscopy depends heavily on the "diamond" principle of trocar positioning, which optimizes access and visualization while managing the ergonomic challenges of the surgical team.
Key takeaways for surgical practice include:
Economic Strategy: In resource-limited settings, the use of reusable stainless steel instruments and energy devices is preferable to single-use disposables, which are difficult to source and prone to failure if reused improperly.
The Diamond Principle: Effective surgery requires arranging the surgical site, the camera, and working trocars in a four-sided diamond configuration to maximize reach and visualization.
Safety via Open Access: The Hasson (open) technique for the initial trocar is recommended to minimize fatal vascular and bowel injuries associated with blind entry.
Ergonomic Optimization: Patient rotation is a critical, simple maneuver to prevent surgeon fatigue and maintain a relaxed posture during complex angles of approach.
Complication Management: Immediate recognition and specific stabilization techniques—such as using a Foley catheter for epigastric vessel injuries—are essential for managing intraoperative pitfalls.
Laparoscopy in Resource-Limited Settings
While some critics argue laparoscopy has no role in areas with scarce resources, the benefits to the patient and the hospital’s reputation are substantial. The focus must remain on safe, lifesaving procedures, but when basic care is accessible, the advantages of laparoscopy should not be withheld.
Equipment and Institutional Commitment
Maintenance: Laparoscopic equipment is complex and prone to breakage if mishandled, facitity at these procedures requires significant time and commitment from both surgeons and hospital administration.
Sourcing: Industrialized nations rely on single-use trocars that are difficult to adapt for resource-limited environments. Reusable stainless steel alternatives from markets like India and China are more sustainable.
Mentorship: Due to the risk of unique complications—such as biliary tract injuries in cholecystectomies—surgeons should seek supervised practice before operating independently.
Trocar Positioning: The "Diamond" Principle
The primary objective of trocar positioning is to provide the camera and working instruments clear access to the surgical site. The "diamond" configuration places the surgical site at one corner, the camera at the opposite corner, and two working trocars at the remaining two corners.
Ergonomic vs. Visual Trade-offs
Visualization is generally superior when the camera is placed far from the surgical site. However, this often forces the camera operator to reach between the surgeon’s arms, causing discomfort. Placing the camera closer to the pathology (at an adjacent corner of the diamond) may reduce the quality of the view but increases the comfort and endurance of the surgical team.
Procedure-Specific Configurations
Instrument Constraints
Scope Size: 10mm scopes are more durable and common in resource-limited settings. If 5mm scopes are unavailable, the camera may be restricted to the 11mm umbilical trocar, limiting the surgeon's ability to switch viewpoints.
Trocar Size: Using a 5mm scope allows for more flexibility, as it can be moved between various trocar sites during the operation.
Methodologies for Trocar Placement
The Hasson (Open) Technique
The open technique is preferred for the first trocar, particularly in patients without previous abdominal surgery, to ensure safe entry.
Incision: A 2.5cm (non-obese) to 4cm (obese) transverse supraumbilical incision is made.
Dissection: Dissection proceeds through subcutaneous tissue to the midline of the anterior rectus sheath.
Fascial Incision: The sheath is incised transversely until preperitoneal fat is visible. The hole should be kept as small as possible to minimize gas leakage.
Blunt Entry: The peritoneum is perforated bluntly using the small finger to probe for adhesions or masses.
Retention Sutures: Sutures are placed on either side of the fascial incision. These are used to secure the trocar and tighten the fascia around the cannula to prevent pneumoperitoneum escape.
Trocar Insertion: The trocar is inserted using a blunt obturator. Sharp obturators must be used with extreme caution and withdrawn immediately upon entering the fascia.
Percutaneous Placement Under Visualization
Subsequent trocars are placed percutaneously once pneumoperitoneum has been established.
Visual Guidance: The entry site must be visualized from the inside with the laparoscope. Local anesthetic is injected into the skin, fascia, and peritoneum.
Avoiding Vessels: Surgeons must avoid epigastric vessels, which run parallel to and approximately 5cm lateral to the linea alba.
The Palm Grip: The trocar head is gripped between the thumb and the middle/ring/small fingers. The index finger must be extended along the shaft to act as a "brake," resting against the patient's skin to prevent the trocar from plunging into the abdomen.
Controlled Entry: The surgeon applies controlled pressure with a slight twisting motion. The camera operator must keep the trocar tip in view at all times.
Safety, Pitfalls, and Complications
Avoiding Fatal Injuries
Vascular injuries during trocar placement, particularly perforation of the aorta or iliac arteries, can be fatal. The risk is highest in the lower quadrants where external iliac arteries are nearby. Controlled placement and constant visualization are the primary defenses against "plunging" trocars.
Epigastric Vessel Injury Management
If an epigastric vessel is injured, the trocar should not be withdrawn. A recommended stabilization technique involves:
Passing a Foley catheter through the trocar.
Inflating the balloon.
Sliding the trocar out while pulling the balloon upward against the abdominal wall to apply pressure to the bleed.
Ligating the vessels on either side of the balloon using intracorporeal sutures or a percutaneous closure device.
Ergonomics and Table Positioning
Poor positioning can make surgery unnecessarily difficult. Rotating the patient toward the surgeon allows for a more relaxed posture and better endurance compared to operating on a flat table, which often requires awkward, painful angles.
Trocar Site Hernias
Any trocar site 10mm or larger (except for those in the epigastric region or superior to the liver) is prone to incisional hernias and must be meticulously closed.
Closure: The fascia should be closed with absorbable sutures (or non-absorbable for the Hasson site in obese patients).
Technique: If a percutaneous closure device is unavailable, the skin incision should be widened to allow for a "figure of 8" suture of the fascia from the outside.
