Fluorescent green dye helps surgeons reduce complications after surgery for people with soft tissue sarcoma

Fluorescent green dye helps surgeons reduce complications after surgery for people with soft tissue sarcoma

By
Mayo Clinic Staff

December 24, 2023

A team of researchers at Mayo Clinic has discovered that using fluorescent green dye combined with imaging during surgery for soft tissue sarcoma can help surgeons determine what tissue may be at risk of poor healing. This information allows surgeons to change the wound closure to reduce the risk of complications as the patient heals.

Soft tissue sarcoma forms in tissues that connect, support and surround other body structures, including muscle, fat, blood vessels, nerves, tendons and the lining of joints. An estimated 13,400 people will be diagnosed with soft tissue sarcoma in 2023. More than 30% of people who receive radiation treatment before surgery to remove the cancer experience complications with their surgical wounds.

Patients receive the dye, called indocyanine green, through an IV during surgery. When paired with imaging, the technology is called intraoperative indocyanine green (ICG) fluorescence angiography. The technique allows surgeons to assess the amount of blood flowing in an area of tissue, called tissue perfusion. A lack of blood flow indicates a potential problem with tissue. Surgeons can then remove any tissue that lacks blood flow.

**Wound closure**
On the monitor, the surgeon views the incision during surgery. The white color indicates blood flowing to the tissue. If blood flow was insufficient, the monitor would show a dark spot.

"It basically changed our practice," says Courtney Sherman, M.D., a Mayo Clinic orthopedic oncologist who led the research. "This technology gave us eyes beyond human eyes — a window into the blood supply to the patient's skin."

The team published its findings in the Journal of the American Academy of Orthopaedic Surgeons (JAAOS) in May 2021 and in the American Academy of Orthopaedic Surgeons (AAOS) Global Research and Reviews in August 2021.

While the surgical technique isn’t yet in standard use for soft tissue sarcoma care across the U.S., surgeons caring for people with soft tissue sarcoma at Mayo Clinic now regularly use ICG fluorescence angiography.

How wound issues complicate healing for people with soft tissue sarcoma

Soft tissue sarcoma often affects the arms and legs; surgery is a common treatment. The surgeon usually removes the cancer as well as some healthy tissue around it.

Patients typically receive radiation therapy to shrink the cancer before surgery, says Dr. Sherman. Orthopedic oncologists believe the combination of surgery and radiation increases the likelihood that a surgeon can remove the cancer without needing to remove the entire limb.

Though modern radiation therapy is significantly more precise than in previous decades, it still may damage healthy cells along with cancer cells. This may lead to infection, or the radiation may destroy the genetic material in healthy cells and cut off blood supply. Over time, tissue that lacks blood supply dies, and the patient may require another surgery to remove this additional tissue.

Treatment for soft tissue sarcoma with radiation therapy followed by surgery has an infection risk of 38% for all patients. The risk of the surgical incision reopening in the same group is 42.3%, says Dr. Sherman.

"Wound healing issues disrupt the patient's treatment," says Dr. Sherman. "Due to wound complications, there has been a lot of 'back to the OR' for patients who have radiation therapy plus surgery for soft tissue sarcoma. It's a big deal if we can keep these patients out of the OR."

Mayo Clinic’s research on ICG fluorescence

In their May 2021 JAAOS article, Mayo Clinic researchers described their finding that ICG fluorescence angiography could not only predict wound complications for patients who had radiation therapy before surgery but also allow surgeons to make changes during the procedure to reduce the risk of complications. The 23-patient study found that intraoperative ICG fluorescence angiography could predict with a high degree of accuracy where complications with wound healing might occur, particularly for patients with soft tissue sarcoma in the lower extremities of the body (from the hip down).

For the AAOS Global Research and Reviews article in August 2021, Dr. Sherman and the research team reported on a study conducted between October 2017 and September 2019 based on records for patients who received surgery for soft tissue sarcoma with ICG fluorescence angiography. The researchers compared these patients' experiences to those of patients who had received surgery without ICG fluorescence angiography. The study included 88 patients. Researchers found significantly lower rates of infection and surgical incisions reopening in patients who received ICG angiography compared with patients whose surgery did not include this technology.

"Using ICG green fluorescence is simple, straightforward and effective," says Dr. Sherman. “It’s making recovery less challenging for people with soft tissue sarcoma by reducing complications from surgery."