Feasibility and safety of minimally invasive radioguided parathyroidectomy using very low intraoperative dose of Tc-99m MIBI

Progress in the Management of Mediastinal Ectopic Parathyroid Adenomas: The Role of Minimally Invasive Surgery

Background/Objectives: Primary hyperparathyroidism (PHPT) is a prevalent endocrine disorder, with ectopic mediastinal parathyroid adenomas accounting for up to 30% of cases, posing significant diagnostic and surgical challenges. While traditional management relies on invasive procedures, minimally invasive techniques such as video-assisted thoracoscopic surgery (VATS) have emerged as viable alternatives. This study addresses a gap in the current literature by presenting our experience with VATS for mediastinal ectopic parathyroid adenomas, particularly in underreported retrotracheal/paraesophageal locations. By integrating a retrospective case series with a systematic literature review, we highlight evolving surgical strategies and their implications for patient outcomes in anatomically complex cases. Methods: A retrospective analysis was conducted over a three-year period on patients diagnosed with mediastinal ectopic parathyroid adenomas. Data on demographic characteristics, preoperative imaging, surgical techniques, intraoperative findings, and postoperative outcomes were collected. This study primarily compared the outcomes of VATS with those of traditional thoracotomy, with a focus on surgical success, complication rates, and length of hospital stay. Results: Six patients underwent surgical resection for mediastinal ectopic parathyroid adenomas (two intrahymic and four retrotracheal/paraesophgeal). VATS was the preferred approach in all cases, with one patient requiring conversion to thoracotomy due to challenging vascular anatomy. Surgical success, defined as the normalization of postoperative serum calcium levels, was achieved in all cases. The median operative time was 80 min, and the mean hospital stay was 6.25 days. One patient developed transient postoperative hypocalcemia, necessitating supplementation. No major surgical complications were observed. Conclusions: This study supports VATS as a safe and effective approach for mediastinal ectopic parathyroid adenoma resection, offering reduced morbidity and shorter recovery times compared to traditional open surgery. The findings align with emerging evidence advocating for minimally invasive techniques in complex mediastinal surgeries.

Radioguided parathyroidectomy: How does it contribute to surgery?

OBJECTIVE

To evaluate whether a radioguided approach allows a higher intraoperative detection rate of adenoma and a minimally invasive parathyroidectomy (MIP), with the same or better cure rate of hyperparathyroidism secondary to parathyroid adenoma.

METHODS

This was an observational, prospective, single-center study involving 254 consecutive patients with primary hyperparathyroidism, between 2017 and 2022. A total of 258 procedures were performed: 129 non radioguided (NRS) and 129 radioguided (RS) (112 with intravenous 99mTc- MIBI and 17 with ultrasound-guided intralesional 99mTc-MAA injection) with an intraoperative gamma probe and gamma camera. Follow-up was performed for at least one year.

RESULTS

There were no differences between the groups in terms of age, sex, preoperative calcium or parathyroid hormone levels, adenoma localization with 99mTc-MIBI-gammagraphy and ultrasound, and surgical morbidity. Intraoperative surgical localization was 97.7% in both groups. Statistically significant differences supported RS: It allowed to perform MIP (RS: 96.9%, NRS 88.4%; p = 0.015), also in patients with previous neck surgery (RS: 75%, NRS: 28%; p = 0.019) and with ectopic adenomas (RS: 93.3%, NRS: 71.4%; p = 0.012). The operative time was significantly shorter (RS: 51 min, NRS: 59.79 min; p = 0.005). There were no significant differences in the postoperative complications between the groups. Biochemical cure at six months was achieved in RS: 97.7% and NRS: 93.8% (p = 0.12).

CONCLUSIONS

Radioguided MIP is useful in ectopic adenomas and in patients with previous cervical surgery and allows a minimally invasive approach more frequently. It is a safe surgery, easily reproducible by an endocrine surgeon and requires usual equipment found in operating rooms.

Low-dose radio-guided parathyroidectomy: A non-inferiority systematic review and meta-analysis

BACKGROUND

Performing MIRP procedure with a 20-fold less MIBI isotope dose allows lower radiation exposure risk for both patient and staff and reduce the overall cost of the procedure. The main goal of this systemic review and meta-analysis is to prove the non-inferiority of the very low dose MIRP compared to the standard dose.

METHODS

We performed a systemic review and meta-analysis of three different electronic databases - PubMed, Web of Science and google scholar. Meta-extraction was conducted in accordance with PRISMA guidelines.

RESULTS

Among 4750 studies imported for screening, only 13 studies were selected for the meta-analysis. Analyzed data from the 13 selected studies performed with low dose MIRP demonstrated a detection rate greater than 97 ​% and a success rate greater than 95 ​%, which is comparable to the cure rate required by current guidelines, as well as to data published by studies using the original high dose protocol.

CONCLUSION

Very low dose MIRP is not inferior to the high dose original MIRP and may be used in separate day protocol routinely.

Comparison of intraoperative imaging with a portable gamma camera with extemporaneous histology in minimally invasive surgery for primary hyperparathyroidism

INTRODUCTION

The curative treatment of primary hyperparathyroidism (PPH) is surgical and today it can be performed by minimally invasive surgery (MIS) and also be radioguided (RG) if a radiopharmaceutical with affinity for the parathyroid tissue that can be detected with gamma-detector probes or with a portable gamma camera (PGC) is injected.

AIM

The objective is to assess whether intraoperative scintigraphy (GGio) with PGC can replace intraoperative pathological anatomy (APio) to determine if the removed specimen is an abnormal parathyroid.

MATERIAL AND METHOD

92 patients underwent CMI RG--HPP with PGC after the administration of a dose of 99 mTc-MIBI. The information provided by the PGC in the analysis of the excised specimens is qualitatively compared (capture yes/no) with the result of the intraoperative pathological anatomy (APio). The Gold standard is the definitive histology.

RESULTS

120 excised pieces are evaluated with GGio and APio. There were 110 agreements (95TP and 15TN) and 10 disagreements (3FP and 7FN). Of the 120 lesions, 102 were parathyroid and 18 were non-parathyroid. There was good agreement between intraoperative scintigraphy imaging (GGio) and PA, 70.1% according to Cohen's Kappa index. The GGio presented the following values ​​of Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value, Positive Likelihood Ratio, Negative Likelihood Ratio and Overall Value of the Test (93.1%, 83.3%, 96.9%, 68.2%, 5.59, 0.08 and 0.92 respectively).

CONCLUSION

GGio is a rapid and effective surgical aid technique to confirm/rule out the possible parathyroid nature of the lesions removed in PPH surgery, but it cannot replace histological study.

Brown tumor due to primary hyperparathyroidism in a familial case: a case report

BACKGROUND

Primary hyperparathyroidism (PHPT) is an uncommon disorder characterised by hypercalcemia with an increased parathyroid hormone level. We reported a PHPT familial case with two subjects, a father and a daughter, and both of them had suffered from the brown tumor.

CASE PRESENTATION

The proband, a 43-year-old patient, developed parathyroid adenomas at the age of 15; a histologically confirmed right parathyroid adenoma was removed by parathyroidectomy; and after six months follow-up, the serum calcium level was normalised. At the age of thirty-three, a CT scan of his head and neck revealed a mass in the right maxilla, as well as PHPT (i.e., left inferior parathyroid adenoma). Then, he underwent a biopsy of an exophytic lesion in the right maxilla and was diagnosed by pathology as a brown tumor, with the serum calcium and PTH levels at 2.78 mmol/L and 221 pg/mL, respectively. Subsequently, the patient took a left inferior parathyroid microwave ablation with ultrasound guidance. After three months of follow-up, the serum calcium and PTH levels returned to normal, and the brown tumor was resolved. After three years, it mineralised as revealed in a CT scan. By the time he was 43 years old, during the 28-year follow-up period, the serum calcium and PTH levels were still within the normal range, and there was no discomfort reported. He has consistently taken calcium supplements throughout the 28 years. Since the initial diagnosis, his blood indicators of kidney function have been normal, and ultrasound showed renal calculus in the right kidney and a normal left kidney. The proband's daughter, a 15-year-old girl, experienced left upper extremity pain for ten months. CT scan revealed a mass in the distal left radius, and a giant cell tumor was suspected. A surgical internal fixation was performed, and the pathology showed a brown tumor. Laboratory tests revealed a serum parathyroid hormone (PTH) level of 1554pg/mL, calcium level of 3.14 mmol/L, phosphorus level of 0.72 mmol/L, and alkaline phosphatase level of 1892 U/L. Given the osteitic changes and elevated levels of calcium and PTH, ultrasonography was performed, after which a mass was detected measuring 19 × 9 × 7 mm mixed with solid components and cystic fluid in the right thyroid gland. The results of 99mTc-MIBI scintigraphy confirmed the abnormal accumulation of 99mTc-MIBI in the right thyroid gland but not seen in the bilateral parathyroid glands. The patient underwent thyroidectomy, and the postoperative pathology report indicated an intra-thyroid ectopic parathyroid adenoma. The serum calcium and PTH levels became normal at 4 h after surgery. One to three months after operation, the serum calcium level was low, while the serum PTH level was high. Then, the patient was advised to take calcium supplements. Until the sixth month after the operation, the serum calcium level and serum PTH level returned to normal, and the bone pain was relieved. The patient's blood tests for kidney function remained normal. There was no evidence of bilateral kidney disease (such as nephrolithiasis or nephrocalcinosis) detected by ultrasound scan. There were several similarities in the state of illness between these two subjects. Both the father and the daughter developed parathyroid adenomas at the age of 15, and there was no lesion in other endocrine glands. And genetic testing revealed mutations in the CDC73 genes in both father and daughter. On the other hand, there were also a few differences. The father's first signs of brown tumor were in the right maxilla, while the daughter's appeared in the distal left radius. The father presented pathological changes in the left and right parathyroid glands, whereas the daughter presented with an ectopic parathyroid adenoma in the right thyroid gland.

CONCLUSION

We report a familial case in which father and daughter were diagnosed to have brown tumors due to parathyroid adenoma and ectopic parathyroid adenoma, and genetic testing revealed CDC73 gene mutations in both. Therefore, in the diagnostic and differential process of young patients having bone disease, clinicians should not only focus on the clinical manifestations of the skeleton, but also implement a comprehensive analysis of systemic symptoms, considering the possibility that the patient has familial PHPT.

Radio-guided procedure in minimally invasive surgery for primary hyperparathyroidism

Minimally invasive parathyroidectomy, of choice in most cases of primary hyperparathyroidism, shows a high detection rate, based on precise preoperative localization by MIBI scintigraphy (SPECT/CT) and neck ultrasound. Radioguided minimally invasive parathyroidectomy is an even more effective technique, which shortens surgical times, maintains minimal incision and few complications, allows immediate verification of parathyroid adenoma removal and is especially interesting in patients with ectopic lesions or cervical surgical history. In this paper, the indications, protocols and differences between the two available radioguided parathyroid surgery procedures (MIBI and R.O.L.L.) are exposed.

Radioguided surgery in primary hyperparathyroidism: a review of the different available techniques

Parathyroidectomy has evolved over the years from bilateral neck exploration to a single gland approach using minimally invasive surgery. The precise presurgical localization of the problem gland, using functional techniques, such as double-phase scintigraphy with [^99mTc] Tc-MIBI including SPECT-CT and PET-CT with [¹⁸F]-Choline and morphological ones, such as ultrasound have played a crucial role in this paradigm's shift. Radioguided surgery techniques have also adapted and grown with new contributions known for their indication in other fields. Thus, we currently have a wide range of techniques that have been added to the minimally invasive radioguided parathyroidectomy with [^99mTc] Tc-MIBI, which was the first on the stage and for which more experience exists. Among them, in this update, we will discuss parathyroidectomy using ultrasound-guided ROLL technique as well as with the use of ¹²⁵I seeds and finally, hybrid techniques that use radiotracer and fluorescence.

Gonioprobe, an Innovative Gamma-probe to Guide Parathyroid Radioguided Surgery: First Clinical Experiences with Navigator and Lock-ontarget Functions

BACKGROUND

Radioguided surgery represents a validated technique for the detection and the excision of abnormal parathyroid glands responsible for primary hyperparathyroidism (PHPT). To date little attention has been paid as to how the characteristics of gamma-probes can influence surgical procedure and time, thus having an impact on postoperative morbidity, hospitalization and costs.

METHODS

We designed a new prototype of gamma-probe, the Gonioprobe, and tested its clinical utility in the operating room. Gonioprobe, thanks to its 5 scintillating independent crystals, performs the dual function of Navigator and Lock-on-target. These characteristics allow the immediate guidance of the surgeon's hand towards the source with very high precision, and with a much higher spatial resolution than commercial probes. Gonioprobe was used during intervention to detect abnormal parathyroid tissue, and to ensure no radioactivity in surgery bed after adenoma removal.

RESULTS

We tested our gamma-probe on parathyroid adenomas particularly difficult to identify at a visual inspection due to anatomy modifications from previous neck surgery and/or characterized by uncommon localization. Moreover, parathyroid adenomas were hardly removable due to the proximity to the esophagus, neck vessels and/or recurrent laryngeal nerve (RLN). An intraoperative nerve monitoring system was used to protect the recurrent laryngeal nerve from injuries. Parathyroid hormone (PTH) assay and frozen biopsy confirmed the successful excision of the adenomas.

CONCLUSION

The intraoperative use of the innovative Gonioprobe along with the nerve monitoring system allowed an accurate and safe removal of parathyroid adenomas and offered a significant advantage by reducing surgical time and postoperative complications, as well as hospitalization and costs.

Primary hyperparathyroidism due to ectopic parathyroid adenoma in an adolescent: a case report and review of the literature

PURPOSE

Primary hyperparathyroidism (PHPT) is a common endocrine disorder and is usually diagnosed in adults. PHPT due to ectopic parathyroid adenoma in adolescents is rare.

METHODS

We describe the case of a 15-year-old boy with PHPT due to ectopic parathyroid adenoma. A review of the literature of PHPT in adolescents was performed, focusing on etiology, clinical presentation, preoperative localization methods, pathology, and treatment.

RESULTS

The patient was successfully treated with surgery and was followed up for 5 years with no signs or symptoms of hyperparathyroidism. By reviewing the literature, only seven cases of PHPT associated with ectopic parathyroid lesions in adolescents have been reported. Parathyroidectomy is the only known curative treatment. Accurate preoperative localization of the target lesion is critical.

CONCLUSIONS

This study should raise awareness of the diagnosis and treatment of PHPT due to ectopic parathyroid adenoma/carcinoma in adolescents.

Thoracoscopic removal of ectopic mediastinal parathyroid adenoma causing hyperparathyroidism: a rare entity

Ectopic mediastinal parathyroid adenomas are uncommon. Here, we report the successful thoracoscopic removal of a mediastinal parathyroid adenoma from a patient with hypercalcemia. A 58-year-old female patient was referred to our department with persistent hypercalcemia. Serum calcium and phosphorus levels were 13.2 mg/dl and 2.5 mg/dl respectively, while the intact parathormone level was 798.9 pg/ml. Parathyroid computed tomography revealed a solid and well-defined mass at the anterior mediastinum close to the distal aorta. Once the contrast was enhanced, our pre-diagnosis was ectopic parathyroid adenoma. The mass was detected at the anterior mediastinum, dissected free from the surrounding tissue and excised. The capsulated mass, which had a diameter of 3 × 1.5 × 0.7 cm, was confirmed as parathyroid adenoma histopathologically. Postoperative calcium and parathormone levels decreased dramatically to normal levels. Anterior mediastinal localization of an ectopic parathyroid adenoma is a rare entity. The transsternal approach is the most preferred method, but video-thoracoscopy can be used safely and effectively.

Comparison of video-assisted thoracic surgery with open surgery in the treatment of ectopic mediastinal parathyroid tumors

Background

To investigate the therapeutic effect of different surgical treatment for ectopic mediastinal parathyroid tumors and pathological features.

Methods

A total of 21 patients who were diagnosed with ectopic mediastinal parathyroid tumors and underwent surgeries in our department from May 1995 to May 2015 were collected and retrospectively analyzed.

Results

Twenty-one patients including 8 female (36.4%) and 13 male (63.6%) were collected. Among these patients, 9 cases were treated with video-assisted thoracic surgery (VATS), while 13 cases were treated with open surgery (including one secondary open operation after thoracoscopic operation). The average size of mediastinal tumors was 2.17±1.22 cm. For the post-operational pathology, 16 cases (76.2%) were diagnosed as ectopic parathyroid adenoma; 4 cases (19.0%) were diagnosed as parathyroid hyperplasia, while only 1 case (4.8%) was diagnosed as parathyroid adenocarcinoma.

Conclusions

Parathyroid adenoma accounts for the major pathological type of ectopic mediastinal parathyroid tumors. In addition, the correct diagnosis with precise preoperative location was the key for the treatment of ectopic mediastinal parathyroid tumors accompanied with hyperparathyroidism. Surgical intervention was demonstrated to be an effective way for the treatment of ectopic mediastinal parathyroid tumors with satisfied therapeutic outcome, especially for the VATS due to its unique clinical advantages. However, there may some difficulties when locating ectopic mediastinal parathyroid tumor less than 1 cm and the operators should be very cautious when performing thoracoscopic operations.