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NEEDLE ELECTRODE WITH SALINE ENHANCEMENT RFA TECHNOLOGY

  • Advantages of a wet electrode:
    • The application under US and CT guidance is very easy.
    • Multiple treatments create overlapping regions of tissue destruction
    • Low cost of the needle
    • The infusion of NaCl improves the thermal conduction and electrical
    • Conductivity: NaCl minimizes the dehydrating effects of RF energy and continuous saline injection surrounding the electrode tip reduces local carbonization and therefore increasing the size of the tumor necrosis.
    • Interest of 5 % saline injection:
      • decrease of perfusion rate (70ml/h)
      • hypertonic saline allows to obtain a significant decrease in tissue impedance.
  • Inconveniences of a wet electrode:
    • Irregular areas of necrosis.
    • With 0.9 % saline infusion, a great volume is necessary (105ml/h) for several applications in a single session.
    • Risk of needle obstruction by coagulated tissue.
    • Risk of sub-capsular and/or extra-capsular diffusion of NaCl solution,
    • when tumors are near the capsule: the side holes must be localized within parenchyma ( > 1 cm inside ).

CT GUIDANCE

Better planning before treatment than US.  The needle tip is localized and placed with precision, thus decreasing the risk of injury to the adjacent structures.  Overlapping can be effective without obscuration of the target by the vapor bubbles formation.  Control of the treatment is better for large tumors and upper segments (4,7,8), which are difficult to visualize.

 

PERCUTANEOUS RFA PROCEDURE

The most important is safety and efficacy.

  • Advantages: Minimal invasive. Conscious sedation. No importance of previous operations. Short hospitalization, fast recovery.
  • Inconveniences: Staging limited to pre operative investigations.
    Risk of tumor track seeding, Tumors too adjacent to other organs (colon, stomach, gall bladder)

INTRA OPERATIVE RFA  PROCEDURE

  • Advantages: Good tumor staging, location of tumors missed by CT and seen on per operative US. Prevention of bleeding and track seeding. Associated Pringle maneuvers. see percutaneous versus operative cases.
  • Inconveniences: General anesthesia. Invasive procedure. Difficult if patients had previous operations. Ultrasonography guidance during RFA is less precise than CT because of  the target obscuration produced by vapor bubbles.  see guidance cases
  • Combined treatment: Resection and RFA for unresectable tumors with possibility of curative treatment.


THE FUTURE: BIPOLAR TECHNIQUE WITH 5 % SALINE INFUSION

Advantages see bipolar cases

  • No pad skin burn.
  • Decrease of saline volume infused.
  • Duration of treatment: 50 % reduction.
  • Areas of necrosis more regular
  • Decrease of the risk of thermal injury to adjacent non-vascular structures, perihilar structures, stomach, colon, and diaphragm.