Randomized Controlled Trial Comparing White Light with Near-Infrared Autofluorescence for Parathyroid Gland Identification During Total Thyroidectomy

Abstract

BACKGROUND: Parathyroid glands are difficult to identify during total thyroidectomies, and accidental resection can lead to problematic postoperative hypocalcemia. Our main goals were to evaluate the effectiveness of using near-infrared light (NIRL) autofluorescence intraoperatively for parathyroid gland identification and to measure its impact on postoperative hypocalcemia incidence. STUDY DESIGN: Total thyroidectomies were performed on 170 patients with different thyroid pathologies, block-randomized (1:1) into 2 equal groups. Among controls, traditional overhead white light (WL) was used throughout. In the experimental group, NIRL was used to enhance parathyroid gland recognition before thyroid dissection. The number of parathyroid glands identified was compared after thyroid dissection in controls using WL vs pre-dissection in the experimental using NIRL and with WL vs NIRL before thyroid dissection in the experimental group. Postoperative serum calcium levels and hypocalcemia rates were compared. RESULTS: The mean number of parathyroid glands identified pre-dissection with NIRL was the same identified post-dissection with WL (3.5 vs 3.6). In the experimental group, converting from WL to NIRL increased the number of glands detected from 2.6 to 3.5 (p < 0.001), and revealed at least 1 previously missed gland in 67.1% of patients. Calcium levels 7.5 mg/dL were one-tenth as common in the NIRL group (p ¼ 0.005). The adjusted odds of hypocalcemia developing increased by 15% for every 5-g increase in thyroid gland weight (odds ratio 1.15; 95% CI 1.06 to 1.25). All hypocalcemia resolved within 6 months. CONCLUSIONS: Using NIRL during thyroidectomy increases intraoperative identification of parathyroid glands, enhances their detection before thyroid dissection, and decreases the incidence of postoperative hypocalcemia.

The impact of near infrared fluorescence imaging on parathyroid function after total thyroidectomy

“…Although the French studies reported less hypocalcemia, as defined as <8 mg/dL on POD#1 and 2, 8,19 the Argentinian study showed less severe (<7.6 mg/dL) hypocalcemia with the use of NIFI 20 . None of the studies showed any differences in long‐term hypocalcemia rates 8,19,20 . In the current study, the mean number of parathyroid glands recognized intraoperatively was the same between the NIFI and conventional surgery groups and 1/3 of the parathyroid glands were seen on NIFI first before they became apparent to the eye.…”

“…Furthermore, there is a suggestion that there was less incidence of inadvertent parathyroidectomies and parathyroid autotransplantations with NIFI versus conventional surgery 8,19 . Although the French studies reported less hypocalcemia, as defined as <8 mg/dL on POD#1 and 2, 8,19 the Argentinian study showed less severe (<7.6 mg/dL) hypocalcemia with the use of NIFI 20 . None of the studies showed any differences in long‐term hypocalcemia rates 8,19,20 .…”

“…The second randomized study on the same field was done by Dip and associates from Argentina 20 . In this study, 85 patients each were randomized to total thyroidectomy with or without NIFI.…”

“…When these studies are analyzed, it could be inferred that this technology may have increased the ability of the study surgeons to identify parathyroid glands when compared with the conventional technique that relies on visual surgical identification alone 8,19,20 . Furthermore, there is a suggestion that there was less incidence of inadvertent parathyroidectomies and parathyroid autotransplantations with NIFI versus conventional surgery 8,19 .…”

How important is the 4-ICG score for a thyroid surgeon?

“…If the angiography is not to be done then why not just assess the fluorescence characteristic of the PG, which is an autofluorescent gland and can be visualized even without injecting Indocyanine dye? 3 This will also reduce the cost and avoid any possible adverse reactions related to the ICG dye. Won't it be a good idea to do angiography just after mobilizing the glands medially and before any attempt at dissecting the PG away from the thyroid lobes is made?…”