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As the "access gateway" for minimally invasive surgery, laparoscopic cannulas directly determine surgical outcomes with their application techniques. Focusing on general surgery and gynecology, this article elaborates on selection strategies, placement skills and complication prevention and management of laparoscopic cannulas.

I. Applications in General Surgery: From Cholecystectomy to Complex Oncological Procedures

1. Standardized Channel Establishment for Cholecystectomy

Laparoscopic cholecystectomy represents the most classic application of laparoscopic cannulas. The standard four-port setup includes: a 10–12 mm observation port at the umbilicus, a 10–12 mm main working port below the xiphoid process, and two 5 mm auxiliary ports beneath the costal margin along the right midclavicular line and right anterior axillary line respectively. Umbilical puncture is the key technical step. The open Hasson technique and closed Veress needle technique each have their own advantages and limitations.

Innovative Techniques: Single-Incision Laparoscopic Cholecystectomy (SILS) adopts a multi-channel cannula through a single umbilical incision to achieve scarless surgery. Dedicated single-port cannulas measure 25–30 mm in outer diameter, housing 3 to 5 independent instrument channels plus one channel for the laparoscope. Core techniques include cross-hand maneuvering to overcome limitations of straight-line vision, use of pre-bent instruments, and suspension and exposure techniques.

2. Quadrant-Based Channel Layout for Colorectal Surgery

Colorectal procedures cover extensive operative fields and require flexible channel arrangement. A 5–6 port configuration is commonly used following the quadrant principle: form a working triangle around the target lesion, with the laparoscope placed on the opposite side. For Natural Orifice Specimen Extraction (NOSE) in low rectal cancer surgery, a 15 mm cannula is used to insert a circular stapler, and specimens are retrieved via the natural orifice (anus) without abdominal incisions.

Special Tips: For obese patients with a BMI over 30, cannula length shall be extended to more than 150 mm, and puncture shall be performed perpendicular to the abdominal wall to avoid operational difficulties caused by excessive oblique angles. When concurrent resection of liver metastases is required, an additional 5 mm cannula is placed beneath the right costal margin for liver retraction.

3. Precise Manipulation for Hernia Repair

Inguinal hernia repair generally adopts a three-port approach: a 10 mm umbilical observation port and two 5 mm working ports on the lower abdomen. Key points include: identifying the course of inferior epigastric vessels under laparoscopy via transillumination to avoid vascular injury; using blunt-tip cannulas to reduce damage to abdominal wall nerves; and inserting large-sized surgical meshes through 10 mm cannulas for direct hernia repair.

Special requirements apply to hiatal hernia and abdominal wall hernia repair: dye such as methylene blue is injected via a cannula to verify the integrity of the gastroesophageal junction. For large hernia repair, a 12 mm cannula is used to introduce a spiral tacker for mesh fixation.

II. Applications in Gynecology: From Routine Procedures to Fertility Preservation

1. Technical Essentials for Uterine and Adnexal Surgery

Cannula placement for myomectomy is determined by the location of fibroids: auxiliary ports on the lower abdomen for anterior wall fibroids, and suprapubic auxiliary ports for posterior wall fibroids. When using an electric morcellator inserted through a 10 mm cannula to extract specimens, a containment bag is mandatory to prevent intra-abdominal dissemination of fibroid tissue.

Ovarian cyst surgery strictly follows the no-tumor spillage principle: place a specimen bag via a 5 mm cannula, then puncture and aspirate cyst fluid inside the bag to avoid implantation and metastasis caused by fluid leakage. For large ovarian tumors, extend the umbilical incision for direct specimen removal to eliminate the risk of malignant cell spread associated with morcellation.

2. Management of Deep Infiltrating Endometriosis

Surgery for Deep Infiltrating Endometriosis (DIE) is among the most challenging laparoscopic procedures. The channel layout accommodates multi-site pelvic manipulation: an umbilical scope port, main working ports on both lower abdominal sides, and a suprapubic auxiliary port. A combination of 5 mm and 10 mm cannulas is routinely used for simultaneous operation of dissectors, electrocoagulators and suction devices.

Key Techniques: A rectal manipulator is applied to expose lesions in the rectovaginal septum. For ureteral endometriosis, a ureteral stent is inserted via a 5 mm cannula for intraoperative guidance. For bladder endometriosis, cystoscopy is performed through a suprapubic cannula.

3. Minimally Invasive Innovations for Fertility-Related Surgery

Tubal reanastomosis demands extreme precision, generally performed with 5 mm cannulas and 7-0 atraumatic sutures. The emerging Transvaginal Hydrolaparoscopy (THL) creates pelvic access via a specially designed vaginal cannula, leaving no abdominal scars, and is primarily used for initial screening of infertility.

Cutting-edge procedures such as uterine transplantation require sophisticated channel design: 6 to 8 cannulas are deployed for vascular dissection, uterine fixation, tubal reanastomosis and postoperative monitoring respectively.

III. Prevention and Management of Complications

The overall incidence rate of cannula-related complications ranges from 1% to 5%, mainly categorized as follows:

• Vascular Injury (0.1%): Major vascular injury is the most severe complication. Prevention: Place the patient in the supine position during umbilical puncture and avoid Trendelenburg position which increases vascular tension; adopt optical visual cannulas; select the open approach for patients with BMI over 30 or a history of abdominal surgery.
• Visceral Injury (0.4%): Bowel injury is the most common type. Prevention: Perform adequate gastrointestinal decompression preoperatively; confirm smooth gas insufflation with a Veress needle before primary puncture; convert to open surgery immediately if severe adhesions are identified intraoperatively.
• Wound Complications: Including incisional hernia (1%–3% risk for ports larger than 10 mm), surgical site infection and bleeding. Prevention: Suture the fascial layer for all ports larger than 10 mm; use blunt dilators instead of sharp incisions to reduce hernia risks; administer local anesthesia at port sites to relieve postoperative pain.

IV. Cutting-Edge Technological Developments

• Fluorescent Laparoscopy: Indocyanine Green (ICG) is injected through dedicated cannulas to enable lymphatic imaging and blood perfusion assessment, which significantly improves the radicality of tumor resection.
• Robot-Assisted Surgery: Robot-specific cannulas have an outer diameter of 8 mm and are equipped with magnetic fixation units to minimize instrument interference. The new-generation robotic system supports autonomous positioning and tracking of cannulas.
• Natural Orifice Transluminal Endoscopic Surgery (NOTES): Customized cannulas are inserted via the stomach, vagina or rectum to achieve complete scarless surgery. This technique has been applied to cholecystectomy and appendectomy.

Conclusion

Laparoscopic cannulas have evolved from simple access devices into a core component of surgical strategies. Surgeons shall formulate individualized plans for cannula selection and application based on surgical types, patient conditions and procedural steps. As surgical procedures grow more complex, higher requirements are set for cannula performance, driving the coordinated advancement of medical devices and clinical techniques.