Intraoperative indocyanine green angiography for predicting postoperative hypoparathyroidism

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.

Will the autofluorescence take over inadvertent parathyroidectomy? Results from a multicentre cohort study

BACKGROUND

Recently, several devices exploiting the near-infrared autofluorescence (NIR-AF) of parathyroid glands (PGs) have been developed. Nevertheless, their impact on both preserving PGs from inadvertent surgical dissection and on post-surgical hypoparathyroidism (hypoPTH) is controversial.

METHODS

A retrospective study of 845 patients undergoing thyroid surgery in 2 academic tertiary centres was conducted. In 291 patients, a NIR-AF device was used during surgery to identify PGs. The characteristics of the cohort were examined. The number of PGs identified during surgery, missed PGs, auto-transplants, inadvertent parathyroidectomies, as well as the occurrence of transient and permanent hypoPTH, were analysed.

RESULTS

The use of NIR-AF device resulted in a higher identification of PGs (92% versus 88%, p = 0.0008), and a significant reduction in the number of PGs inadvertently removed and detected on histopathological examination (4.7% versus 6.5%, p = 0.045). An increase in PG auto-transplantations was observed in the NIR-AF + group (10.4% versus 3.5%, p < 0.0001). The use of NIRAF did not significantly impact the occurrence of either transient or permanent hypoPTH.

CONCLUSION

Intraoperative NIR-AF detection is a promising technology to reduce incidental parathyroidectomies in thyroid surgery. The impact of this technology on the occurrence of post-surgical hypoPTH needs to be furtherly investigated.

Intraoperative Management of Parathyroid Glands and Long-Term Outcome of Parathyroid Function Following Total Thyroidectomy

Background/Objectives: In situ preservation is the primary strategy to preserve parathyroid gland (PG) function during thyroid surgery, while autotransplantation is used when inadvertent removal or devascularization occurs. Deciding on the optimal approach intraoperatively for exposed PGs remains challenging. This study evaluates intraoperative PG management strategies and long-term outcomes of PG function following total thyroidectomy. Methods: This retrospective study included 543 patients undergoing primary total thyroidectomy, excluding those with comorbid parathyroid disease. A stabbing test assessed the vascular supply of exposed PGs. PGs with fresh blood oozing after the test were preserved in situ; otherwise, they were autotransplanted. Intact parathyroid hormone (iPTH) and ionized calcium (iCa) were measured preoperatively and on postoperative day 1 (PO-1D), and during follow-up. Permanent hypoparathyroidism (PHPS) was defined as iPTH < 15 pg/mL, iCa < 4.2 mg/dL, or continued need for calcitriol or calcium supplementation after a postoperative period of 12 months (PO-12M). The PHPS rate was compared with the corresponding intraoperative PG status. Results: A total of 528 patients were enrolled in this study. At PO-1D, 434 patients (82.2%) had iPTH ≥ 15 pg/mL, 65 (12.3%) had iPTH between 4 and 15 pg/mL, and 29 (5.5%) had iPTH < 4 pg/mL. At PO-12M, 527 patients (99.81%) had iPTH ≥ 15 pg/mL, 1 (0.19%) had iPTH between 4 and 15 pg/mL, and none had iPTH < 4 pg/mL. Five patients (0.95%) were in PHPS after PO-12M. Among the 462 patients with at least one viable PG preserved in situ, the PHPS rate was 0.2%, compared to 6.1% (66 patients) for those without a viable PG preserved in situ (p < 0.001). Conclusions: Permanent hypoparathyroidism is rare when at least one viable PG is preserved in situ during total thyroidectomy. The stabbing test is a simple, useful, and cost-effective method to assess the vascular supply of exposed PGs, providing surgeons with essential information for intraoperative PG management.

Intraoperative strategies in identification and functional protection of parathyroid glands for patients with thyroidectomy: a systematic review and network meta-analysis

BACKGROUND

This study aimed to assess the benefits and limitations of four intraoperative visualization of parathyroid gland (IVPG) strategies in the identification and functional protection of parathyroid glands (PGs).

METHODS

We searched PubMed, the Cochrane Central Register of Controlled Trials, CNKI, EMBASE, Web of Science and Google Scholar databases until 30 June 2023. Four IVPG strategies were composed of the naked eyes (NE) and three imaging strategies: autofluorescence (AF), indocyanine green fluorescence (ICGF), and carbon nanoparticles (CN). We performed a pairwise meta-analysis (PMA) for direct comparisons and a Bayesian network meta-analysis (NMA) for indirect comparisons.

RESULTS

A total of 29 eligible studies were included. According to NMA and PMA, AF had significantly lower rates of postoperative hypocalcemia and hypoparathyroidism, PG inadvertent resection, and PG auto-transplantation compared to NE, while had significantly higher rate of PG identification. CN showed significantly lower rates of postoperative hypocalcemia and hypoparathyroidism, and PG inadvertent resection compared to NE in PMA and NMA. ICGF showed a significantly higher rate of PG auto-transplantation compared to NE in PMA and AF in NMA. According to SUCRA values, AF showed the best advantage in reducing the rate of postoperative hypocalcemia (0.85) and PG inadvertent resection (0.89), and increasing the rate of PG identification (0.80). CN had the greatest advantage in reducing the rate of postoperative hypoparathyroidism (0.95). ICGF ranked the highest in the rate of PG auto-transplantation (0.98).

CONCLUSIONS

Three imaging strategies demonstrate significant superiority over NE in the intraoperative PG identification and functional protection. AF is the best strategy in reducing the incidence of postoperative hypocalcemia, increasing the rate of PG identification, and reducing the rate of PG inadvertent resection and auto-transplantation. ICGF has great value in assessing PG viability, leading to the trend towards PG auto-transplantation. CN is the best strategy in reducing the incidence of postoperative hypoparathyroidism.