Heterogeneous and low-intensity parathyroid autofluorescence: Patterns suggesting hyperfunction at parathyroid exploration
Introduction
Primary hyperparathyroidism (hyperparathyroidism) has a prevalence of 15.7 per 100,000 in the US population1 and if untreated can cause serious complications, including nephrolithiasis, chronic kidney disease, and osteoporosis.2 In eligible patients, surgery is the standard of care.3 Nevertheless, intraoperative identification and assessment of the parathyroid glands (PGs) can be challenging even for experienced surgeons. Neck ultrasound and sestamibi scans are the 2 most commonly used localizing studies, accuracies of which range between 59% and 89% and 54% and 88%, respectively.4 Despite the advances in these imaging modalities, the success of parathyroid surgery significantly depends on surgeon experience and has been reported to range from 91% to 100%.5, 6 The challenges with parathyroid localization and the importance of surgeon experience for a successful parathyroid surgery led to the famous quote by the interventional radiologist John L. Doppman: “In my opinion, the only localizing study indicated in a patient with untreated hyperparathyroidism is to localize an experienced parathyroid surgeon.”7
Over the years, several imaging modalities have been proposed to localize PGs intraoperatively, including the use of aminolevulinic acid,8 methylene blue,9 a handheld gamma probe,10 and most recently indocyanine green fluorescence.11 However, these modalities could not consistently identify PGs and were associated with adverse effects, such as injection-related complications, allergy, radiation exposure, and photosensitivity.12 Furthermore, none of them predicted parathyroid function.13
Recently a novel method of identification that relies on the detection of autofluorescence from PGs using near-infrared fluorescence imaging (NIFI) has become available.14 Initial reports have found up to 98% detection rates of PGs using this technique.15 More recently it has also been suggested that rates of postoperative hypocalcemia after total thyroidectomy may be decreased with the use of this technology.16 Despite many authors reporting the ability to detect autofluorescence from PGs intraoperatively,15, 17 whether this technology could be used to differentiate between hyperfunctioning and normofunctioning PGs has never been studied. Naturally a modality that could differentiate between hyperfunctioning and normofunctioning PGs would be very useful during parathyroid exploration. Therefore it is crucial to investigate this technology for a potential use in this regard. Our hypothesis was that the pattern of autofluorescence exhibited by hyperfunctioning versus normofunctioning PGs could be different. The aim of this study was to define these differences in autofluorescence patterns during parathyroid exploration for hyperparathyroidism.
Section snippets
Study design
This was a prospective clinical study approved by the Institutional Review Board at the Cleveland Clinic. All study patients underwent bilateral neck exploration for hyperparathyroidism using autofluorescence imaging by a single surgeon (E.B.) between July 2016 and February 2018. Patients undergoing reoperative surgery were excluded.
The autofluorescence patterns between hyperfunctioning and normofunctioning PGs have never been compared before. Therefore an arbitrary number of 50 patients was
Results
A total of 50 patients underwent bilateral neck exploration for hyperparathyroidism. A PG was localized successfully by preoperative ultrasound in 29 of 50 (58%), by sestamibi in 28 of 48 (58%), and by concordance of both studies in 21 patients. In 20 patients the sestamibi, in 21 patients the ultrasound, and in 13 patients both sestamibi and ultrasound were negative. Based on intraoperative findings, 31 patients were found to have a single adenoma, 11 patients double adenomas, and 8 patients
Discussion
To our knowledge this is the first study in the literature suggesting that different patterns of autofluorescence are exhibited by hyperfunctioning versus normofunctioning PGs in hyperparathyroidism. Despite the previous studies reporting the use of parathyroid autofluorescence imaging to identify PGs during thyroidectomy and parathyroidectomy,15, 17 its use to predict parathyroid function has not been reported before. We have found that hyperfunctioning glands have heterogeneous and
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2023, American Journal of SurgerySmaller parathyroids have higher near-infrared autofluorescence intensity in hyperparathyroidism
2022, Surgery (United States)Citation Excerpt :One study of 96 patients undergoing parathyroidectomy for both primary and secondary hyperparathyroidism found a correlation of intensity with preoperative calcium and preoperative serum parathyroid hormone (PTH) levels based on the surgeon’s subjective rank of fluorescence based on a scale of low-medium-high.18 Another study compared the fluorescence from normal and excised parathyroid glands in 50 patients having surgery for hyperparathyroidism capturing images from both in situ and excised glands.19 They found a higher intensity with normofunctioning glands compared with hyperfunctioning glands.