Incremental value of magnification and indocyanine green for parathyroid preservation in thyroid surgery

Efficacy and role of indocyanine green angiography in thyroidectomy: a systematic review and meta-analysis

PURPOSE

This study evaluates the role and effectiveness of indocyanine green (ICG) angiography in conventional thyroidectomy, comparing its outcomes with those of the naked-eye (NE) technique.

METHODS

A comprehensive literature search was conducted in PubMed, EMBASE, and the Cochrane Library databases through November 2024. Meta-analyses were performed on the selected studies. We compared the rates of parathyroid gland (PG) identification, autotransplantation, hypoparathyroidism, hypocalcemia, and postoperative levels of intact parathyroid hormone (iPTH) and calcium between the ICG and NE groups.

RESULTS

We analyzed 29 studies involving 2,393 thyroidectomies. The PG identification rate was significantly higher in the ICG group at 84.7% (95% CI: 77.5-90.0%) than in the NE group (OR = 1.49, 95% CI: 1.26-1.79). Additionally, the rate of parathyroid autotransplantation was higher in the ICG group (OR = 2.18, 95% CI: 1.56-3.03). The transient hypoparathyroidism rate in the ICG group was 11.0% (95% CI: 5.3-21.5%), which was slightly lower than that in the NE group, although the difference was not statistically significant. Conversely, the transient hypocalcemia rate was significantly lower in the ICG group at 13.2% (95% CI: 8.6-19.6%) than in the NE group (OR = 0.50, 95% CI: 0.30-0.85). No significant differences were observed between the two groups in 1-day postoperative iPTH or calcium levels.

CONCLUSION

This meta-analysis demonstrates the superior efficacy of ICG angiography over the NE technique during thyroidectomy. ICG angiography resulted in a higher PG identification rate and significantly reduced postoperative transient hypocalcemia compared to those in the NE approach.

A prospective cross-sectional study on hypocalcemia after total thyroidectomy in patients with Graves' disease: insights on secondary hyperparathyroidism

PURPOSE

To investigate the parathyroid function and calcium (Ca) levels in the secondary hyperparathyroidism (SHPT) state in patients with Graves' disease.

METHODS

We examined 31 consecutive patients with Graves' disease without chronic kidney disease, who were treated with total thyroidectomy. The patients were divided into a normal parathyroid hormone (PTH) group (NPTH group; n = 19) with a PTH level ≤ 65 pg/mL, and a secondary hyperparathyroidism group (SHPT group; n = 12), with a PTH level > 65 pg/mL. The PTH and Ca-related parameters were examined and the risk factors for postoperative hypocalcemia were analyzed.

RESULTS

The preoperative Ca level was significantly lower (2.24 ± 0.06 vs. 2.31 ± 0.07 mmol/L, p < 0.05) in the SHPT group than in the NPTH group. The reduction in PTH, 1,25-dihydroxyvitamin D (1,25(OH)2D), and Ca levels from the preoperative day to the next morning was significantly greater in the SHPT group than in the NPTH group (p < 0.05). When intraoperative factors were included, the decrease in the PTH level alone was significant. SHPT was a significant factor in determining the extent of PTH reduction.

CONCLUSIONS

Hyperfunctioning parathyroid glands in the SHPT state were more susceptible to postoperative PTH reduction, which, combined with low preoperative Ca levels, increased the risk of postoperative hypocalcemia in patients with Graves' disease.

Significant role of 1,25-dihydroxyvitamin D on serum calcium levels after total thyroidectomy: a prospective cohort study

Introduction

Although active vitamin D (VD) has been used both preoperatively and postoperatively to prevent hypocalcemia risk in patients undergoing total thyroidectomy, the role of 1,25-dihydroxyvitamin D (1,25(OH)2D) has not been examined. This study comprehensively investigated the effects of 1,25(OH)2D on calcium (Ca) concentrations after total thyroidectomy.

Methods

Serum Ca, parathyroid hormone (PTH), and 1,25(OH)2D levels were measured in 82 patients with thyroid disease before and after surgery.

Results

Serum Ca, PTH, and 1,25(OH)2D levels decreased significantly on the morning of the first postoperative day. Notably, the decrease in 1,25(OH)2D concentration was significantly lower than that of PTH concentration (10.5 ± 33.4% vs. 52.1 ± 30.1%, p<0.0001), with 28% of patients showing increases in 1,25(OH)2D. The only factor predicting a postoperative 1,25(OH)2D decrease was a high preoperative 1,25(OH)2D concentration. Postoperative 1,25(OH)2D concentrations, as well as the magnitude and rate of decrease from preoperative levels, showed strong positive correlations with preoperative 1,25(OH)2D concentrations (p<0.0001 for all three variables) but not with PTH concentrations. These findings suggest that 1,25(OH)2D concentrations after thyroidectomy were more strongly dependent on preoperative concentrations than on the effect of PTH decrease and were relatively preserved, possibly preventing sudden severe postoperative hypocalcemia. A high 1,25(OH)2D level was the most important preoperative factor for hypocalcemia (<2 mmol/L; p<0.05) on the first postoperative day; however, only PTH decrease was statistically significant (p<0.001) when intraoperative factors were added. In the PTH >10 pg/mL group, the decrease in 1,25(OH)2D levels was significantly associated with postoperative hypocalcemia (p<0.05). Similarly, in the PTH levels >15 pg/mL group, a decrease in 1,25(OH)2D concentration was a significant factor, and the amount of PTH decrease was no longer significant.

Conclusion

1,25(OH)2D plays an important role in preventing sudden, severe hypocalcemia due to decreased PTH levels after total thyroidectomy, whereas high preoperative 1,25(OH)2D levels are a significant risk factor for postoperative hypocalcemia. Optimizing preoperative protocols to adjust Ca, PTH, and 1,25(OH)2D levels to improve the management of patients undergoing total thyroidectomy and to prevent extreme intraoperative PTH decreases may reduce the risk of hypocalcemia.