Baseline intraoperative intact parathyroid hormone levels in parathyroid surgery

The effect of intraoperative autofluorescence monitoring on unintentional parathyroid gland excision rates and postoperative PTH concentrations-a single-blind randomized-controlled trial

PURPOSE

Intraoperative imaging of parathyroid glands (PGs) has been developed in order to reduce the risk of unintentional parathyroidectomy during total thyroidectomy. This novel modality is based on their intrinsic characteristic of autofluorescence (AF) after near-infrared light exposure. The aim of this study was to assess the effect of this method on the risk of unintentional PG excision (total or partial) during total thyroidectomy.

METHODS

This was a single-blind, randomized-controlled trial including adult patients who underwent scheduled total thyroidectomy between December 2019 and March 2020. These patients were randomly allocated to two groups: one in which near-infrared autofluorescence imaging (NIRAF) was applied (NIR group) and one without NIRAF (NONIR group). Hormonal and biochemical assessment was performed pre- and 24-h postoperatively. AF findings and the number of PGs autotransplanted were recorded.

RESULTS

One-hundred and eighty patients were eligible. Unintentional (total or partial) PG excision rates during total thyroidectomy in the NONIR (n = 90) and NIR (n = 90) groups were 28.9% [95% confidence interval (CI) 19.8-39.4%] and 14.4% (95% CI 7.7-22.1%), respectively (p = 0.02). Furthermore, NIR reduced the risk of parathyroid tissue presence in the specimen sent for pathology (relative risk 0.51, 95% CI 0.28-0.92; p = 0.02). However, the number of PGs identified by NIR could not predict the risk of postoperative hypoparthyroidism.

CONCLUSIONS

NIRAF imaging during total thyroidectomy led to a significant reduction in PG excision rates. However, this modality did not result in the reduction of postoperative hypoparathyroidism or hypocalcemia risk.

A novel study for fluorescence patterns of the parathyroid glands during surgery using a fluorescence spectroscopy system

PURPOSE

Recently it was reported that the parathyroid glands (PGs) emit autofluorescence when exposed to near infrared light, and a technique using fluorescence to detect the PGs intraoperatively was found to be useful. In some cases, however, it was difficult to detect the PGs. We sought to clarify the situation regarding such undetectable cases.

METHODS

The study comprised 45 patients (50 sides) who underwent thyroid or parathyroid surgery at Kushiro city general hospital between November 2018 and June 2019. We searched for the PGs intraoperatively using a fluorescence spectroscopy system. We statistically considered the factors related to the fluorescence patterns of background in cases in which two PGs could not be confirmed using Fisher's exact test. Factors included age, gender, body-mass index, laterality, disease state, renal function, and comorbidity.

RESULTS

In 41 sides (82%) fluorescence from at least one PG was determined. There was no significant difference in the detection rates among the other clinical factors. A "White out" pattern in which the background was too bright to detect PGs was observed in 11 sides (22%), and a "Black out" pattern in which the background and PGs were dark was observed in 18 sides (36%). Malignant disease was statistically associated with a "White out" pattern. No factors were found to be related to the "Black out" pattern.

CONCLUSION

In malignant disease, we should use this novel approach carefully.

The role of intraoperative parathyroid hormone (IOPTH) determination for identification and surgical strategy of sporadic multiglandular disease in primary hyperparathyroidism (pHPT)

Intraoperative PTH monitoring (IOPTH) made minimally invasive parathyroidectomy in patients with primary HPT possible. However, with the increasing accuracy of preoperative localization studies there is a growing discussion if IOPTH is necessary in patients with localized single gland disease (concordant preoperative localization studies). Different interpretation criteria have been developed - each with their particular advantages and disadvantages, but the "perfect" criterion is still missing. Despite several pitfalls, which can be recognized intraoperatively and do not necessarily lead to a more extensive surgery, IOPTH seems to be a useful adjunct in surgery for PHPT. However, according to current guidelines, selected patients may be operated without IOPTH but need to be informed about the possibly increased risk of recurrent disease.