A patient can face a double-digit percentage chance of sustaining a nerve injury during surgery, depending upon the procedure. For example, people needing their thyroid gland removed are looking at a 15% likelihood of voice changes resulting from damage to their recurrent laryngeal nerves. Now, a new technology can help surgeons know where a patient’s nerves are, lessening the chance of nerve damage. The technology is based on hydrogels, three-dimensional networks of polymers that absorb and retain large amounts of water, and takes aim at the surgical complication of nerve damage that is widespread and persistent.

The collaborative research involving scientists from Oregon State University (Portland, OR, USA) is an important step toward improving a nerve sparing technique called fluorescence guided surgery, or FGS. Specific tissues, in this case nerves can be better detected if they fluoresce – i.e., emit light after absorbing light or some other kind of electromagnetic radiation. For the tissues to do that, they need to be treated with a fluorophore, microscopic molecules that absorb and send out light of specific wavelengths. The scientists developed an effective hydrogel fluorophore based on compounds called pluronics. Also known as poloxamers, pluronics are polymers synthesized by the condensation of ethylene oxide and propylene oxide.

“Nerve sparing techniques have been around for decades, but nerve identification and sparing remain a big challenge, with success rates strongly correlated with an individual surgeon’s skill and experience,” said Adam Alani, a researcher in the OSU College of Pharmacy. “Intraoperative nerve damage affects all surgical specialties and represents a significant problem even for surgeries that are performed all of the time like prostatectomies, hysterectomies, hernia repair and thyroidectomies.”

Successful testing in two animal models – mouse and pig – suggests the new technology is “a clinically viable method for fluorescence guided nerve sparing during thyroidectomy as well as other procedures,” Alani said. And because pluronics already have FDA approval, the technology is eligible for fast-tracked regulation under the agency’s guidelines for “exploratory investigational new drugs.”

The guidelines allow for early phase 1 clinical trial exploratory approaches involving safe microdoses of potential drug candidates, enabling researchers to move ahead more quickly than usual. “Directly administering a contrast agent in the treatment area is an attractive alternative to systemic administration of fluorescent probes,” Alani said. “Selectively labeling tissues only within the surgical field requires a significantly lower dose than systemic administration.”

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