An Outcome Analysis of Utilizing Contrast-free Near-infrared Autofluorescence Imaging in Thyroid Cancer Surgery: a Retrospective Study

Background: Hypoparathyroidism is the most common complication of thyroid surgery. The best way to assume normal parathyroid gland (PTG) function is to preserve them in situ, undamaged. Near-infrared autofluorescence (NIRAF)-imaging has been introduced as a potentially useful adjunct in thyroid surgery.

Objective: To assess the surgical outcomes of NIRAF-imaging utility in thyroid surgery.

Methods: The clinical records of patients who underwent surgery for papillary thyroid carcinoma (PTC) in a 7-month period were retrospectively reviewed. The primary endpoint was to assess NIRAF's impact on postoperative hypoparathyroidism. Secondary endpoints included its impact in preventing inadvertent PTG resection, time to resolution of postoperative hypoparathyroidism, and additional benefits in therapeutic central compartment neck dissection (tCCND).

Results: Fifty consecutive patients underwent surgery for PTC. Total thyroidectomy was performed in 42 patients. Whereas concomitant tCCND was performed in 8 patients. PTG-detection rate was 93% for NIRAF versus 87% for the surgeon (p = 0.04). NIRAF prevented inadvertent resection of 16 PTGs (p < 0.001). In tCCND, the detection rate of NIRAF was 100% versus 81% for the surgeon (p < 0.01). The rate of transient hypoparathyroidism applying NIRAF was 12% versus 15% (historical cohort) (p = 0.6). However, a significantly prompter resolution of hypoparathyroidism was demonstrated using NIRAF (average time of 2.7 weeks vs. 12.3 weeks; p < 0.0001).

Conclusion: Although NIRAF did not significantly minimize the overall risk of postoperative transient hypoparathyroidism, it demonstrated a trend toward improvement. It also led to prompter resolution of hypoparathyroidism and lowered the risk for inadvertent PTG resection. Therefore, NIRAF seems to be a promising surgical adjunct.