Minimally Invasive Parathyroidectomy as the Surgical Management of Single Parathyroid Adenomas: A Tertiary Care Experience

Preoperative localization of single gland disease in primary hyperparathyroidism: a comparative study for preoperative localization with four-dimensional computed tomography, ultrasonography, and technetium-99m-sestamibi single-photon emission computed tomography

Background

Treatment guidelines for primary hyperparathyroidism (PHPT) recommend high-resolution neck ultrasonography (US), technetium-99m-sestamibi single-photon emission computed tomography (99mTc-sestamibi SPECT), and contrast-enhanced four-dimensional computed tomography (4D CT) as image evaluation methods. This study aimed to compare the sensitivity and accuracy of the three image evaluation methods recommended in the guidelines for patients with PHPT and evaluate the utility of 4D CT for preoperative localization in single gland disease.

Methods

A retrospective medical chart review was performed on 41 patients who underwent surgery for single gland disease at the Department of Otorhinolaryngology, Pusan National University Hospital, between January 2021 and March 2023. All the patients underwent preoperative US, 99mTc-sestamibi SPECT, and 4D CT. The location of the abnormal parathyroid lesion, removed during surgery and confirmed by postoperative pathological examination, was used as the reference standard. The sensitivity, specificity, and accuracy of the three imaging evaluations were assessed and compared to the reference standard location.

Results

The sensitivity, specificity, and accuracy of the imaging modalities were as follows: 4D CT, 95.1%, 98.4%, and 97.6%; US, 82.9%, 95.1%, and 92.1%; and 99mTc-sestamibi SPECT, 78.0%, 97.6%, and 92.7%, respectively. Furthermore, a total of nine cases were identified where accurate localization could not be achieved through US and 99mTc-sestamibi SPECT. The presence of coexisting thyroid lesions was significantly correlated with incorrect localization in preoperative US (P<0.05). The small volume of the parathyroid tumor was significantly associated with an increased rate of false-negatives using 99mTc-sestamibi SPECT (P<0.05).

Conclusions

In the preoperative localization of abnormal parathyroid lesions, 4D CT demonstrated higher sensitivity and specificity than US and 99mTc-sestamibi SPECT. 4D CT can accurately localize abnormal parathyroid lesions, even in cases in which both US and 99mTc-sestamibi SPECT yielded incorrect localizations.

Feasibility of focused parathyroidectomy in developing countries-a scoping review

Background

The mainstay of treatment of primary hyperparathyroidism involves a parathyroidectomy, which depending on the number of affected parathyroid glands and the availability of resources, may involve a bilateral neck exploration with four gland assessment or a minimally invasive, focused parathyroidectomy (FP) necessitating pre-operative localisation. The feasibility of the latter is yet to be demonstrated in developing countries.

Methods

A scoping review was performed with published literature evaluated from the past 15 years (2007 & onwards). Articles were screened and only included if they discussed FP, preoperative localisation, economic impact and they originated from a developing country (upper middle or lower middle-income).

Results

A total of 18 articles met the inclusion criteria, comprising seven developing countries (two upper middle-income and five lower middle-income countries). Preoperative localisation was performed in all studies, with overall accuracy rates of 75.5% for ultrasound and 85.7% for 99mTc sestamibi. A total 1,202 patients (70%) had FP. Five hundred and fifty-five patients underwent FP without intraoperative adjuncts and 647 underwent FP with intraoperative adjuncts, with adjusted cure rates of 95.3% and 99.2% respectively. Overall cure rate for FP was 96.4%.

Conclusions

With access to accurate preoperative localisation and excellent cure rates with and without intraoperative adjuncts, we conclude that FP is feasible in developing countries.

Pitfalls of DualTracer 99m-Technetium (Tc) Pertechnetate and Sestamibi Scintigraphy before Parathyroidectomy: Between Primary-Hyperparathyroidism-Associated Parathyroid Tumour and Ectopic Thyroid Tissue

Diagnosis of primary hyperparathyroidism (PHP) is based on blood assessments in terms of synchronous high calcium and PTH (parathormone), but further management, particularly parathyroid surgery that provides the disease cure in 95-99% of cases, requires an adequate localisation of the parathyroid tumour/tumours as the originating source, with ultrasound and 99m-Technetium (99m-Tc) sestamibi scintigraphy being the most widely used. We aimed to introduce an adult female case diagnosed with PHP displaying unexpected intra-operatory findings (ectopic thyroid tissue) in relation to concordant pre-operatory imaging modalities (ultrasound + dual-phase 99m-Tc pertechnetate and sestamibi scintigraphy + computed tomography) that indicated bilateral inferior parathyroid tumours. A sudden drop in PTH following the removal of the first tumour was the clue for performing an extemporaneous exam for the second mass that turned out to be non-malignant ectopic thyroid tissue. We overviewed some major aspects starting from this case in point: the potential pitfalls of pre-operatory imaging in PHP; the concordance/discordance of pre-parathyroidectomy localisation modalities; the need of using an additional intra-operatory procedure; and the clues of providing a distinction between pathological parathyroids and thyroid tissue. This was a case of adult PHP, whereas triple localisation methods were used before parathyroidectomy, showing concordant results; however, the second parathyroid adenoma was a false positive image and an ectopic thyroid tissue was confirmed. The pre-operatory index of suspicion was non-existent in this patient. Hybrid imaging modalities are most probably required if both thyroid and parathyroid anomalies are suspected, but, essentially, awareness of the potential pitfalls is mandatory from the endocrine and surgical perspectives. Current gaps in imaging knowledge to guide us in this area are expected to be solved by the significant progress in functional imaging modalities. However, the act of surgery, including the decision of a PTH assay or extemporaneous exam (as seen in our case), represents the key to a successful removal procedure. Moreover, many parathyroid surgeons may currently perform 4-gland exploration routinely, precisely to avoid the shortcomings of preoperative localisation.