Summary

This didactic video demonstrates the ten steps of incorporating indocyanine green in sentinel lymph node biopsy in vulvar cancer, where radioactive tracer use is considered to be mandatory and additional blue dye being an option. Indocyanine green improves this approach since it is easily detectable and reproducible.

In vulvar cancer patients the use of an exoscope in conjunction with indocyanine green for open sentinel lymph node biopsy has been described as easy to use with an impressive image quality that is, in a teaching setting.1 Indocyanine green has the potential to be used routinely in the sentinel procedure in vulvar cancer to facilitate the search by direct visualization.2 The use of indocyanine green together with technetium-99 seems to be superior to blue dye for sentinel node detection,2–5 with indocyanine green occasionally helping to detect sentinels when technetium-99 mapping failed.4 One single-center study found a slightly lower sentinel detection rate compared with technetium-99 but indicated that growing experience with the method increased detection rate.6 It has been recommended not to useindocyanine green as the sole tracer for sentinel detection but in conjunction with technetium-99,7 and indocyanine green methodology needs to be consolidated.8

This video consists of intra-operative video footage recorded with an indocyanine green exoscope for open surgery (Vitom-ICG, Karl Storz, Germany) with its different video modes applied:

• Step 1: Scintigraphy for sentinel mapping and detection, optional complementary single photon emission computed tomography (SPECT) for spatial anatomic details of the sentinel’s position.9

• Step 2: Peri-tumoral indocyanine green labeling by intradermal injection around the tumor (25 mg indocyanine green in 5 mL sodium chloride).

• Step 3: Transcutaneous indocyanine green sentinel detection in monochromatic mode.

• Step 4: Transcutaneous gamma probe sentinel detection.

For sentinel detection we combine technetium and indocyanine green. In steps 3 and 4 the indocyanine green camera is used to detect the sentinel signal shining through the skin, confirmed by the radioactive signal.

• Step 5: Incision of skin and fascia.

• Step 6: Identification, tracking, and following lymph vessels: preparation follows the identified lymph vessels to get to the sentinel.

Monochromatic mode can be used in steps 4 and 6 to increase the sensitivity of the indocyanine green signal, while the overlay mode allows visualization of the indocyanine green signal and the surrounding tissue.

Gamma probe and indocyanine green detection are then used alternately to detect the sentinel during preparation and excision in steps 7 and 8.

• Step 7: Gamma probing and indocyanine green sentinel detection.

• Step 8: Sentinel lymph node excision.

• Step 9: Verification of sentinel signal with indocyanine green camera and gamma probe.

• Step 10: Drain placement, skin closure.

Combining radioactive tracer and indocyanine green methods simplifies sentinel lymphadenectomy in vulvar cancer. It adds the benefits of a magnified operating field, provides excellent vision of the lymph vessels and lymph nodes, and allows for minimally invasive and accurate detection and preparation of the sentinels.

The video (figure 1) shows the indocyanine green sentinel lymph node procedure in 10 steps to aid clinicians in reproducing this technique.

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Figure 1

Video still demonstrating the indocyanine green-labeled sentinel lymph node in the groin viewed with the exoscope.