Mediastinal parathyroid glands are often located in a position which is inaccessible through a cervical approach. Because of the significant morbidity of open surgery, the need for minimal invasive approaches is high. More recently, robotic systems have been introduced to refine the dissection and optimize the view in the mediastinal region. We present two cases. The first case is a 34-year-old woman who was diagnosed with primary hyperparathyroidism. Because a bilateral neck dissection disclosed no parathyroid adenoma, we performed a parathyroid sestamibi scan and computed tomographic scan of neck and mediastinum to look for aberrant parathyroid glands. Both showed a parathyroid adenoma in the mediastinum on the left side. The second case is a 66-year-old man. A sestamibi scan showed a parathyroid adenoma of 3 cm in the superior mediastinum which was confirmed by and computed tomographic scan. In both cases, we performed a parathyroidectomy with the da Vinci robotic system through a left-sided approach. Three thoracoports were inserted around the mammary gland for the robot and a fourth auxiliary port was positioned in between. Single-lung ventilation was installed, and the mediastinum was entered by opening the parietal pleura along the left phrenic nerve. The upper margin for dissection was the left brachiocephalic vein that was followed until the right pleura. All the tissue in front of the pericardium was dissected en bloc. The sinking test of the nodule and a preoperative frozen section analysis confirmed the diagnosis of parathyroid adenoma, which was also proven by rapid parathyroid hormone analysis. The resection of a parathyroid adenoma from the aortopulmonary window represents an ideal case for robotic surgery.
From the *Departments of Thoracic and Vascular Surgery and †Hepatobiliary, Endocrine and Transplantation Surgery, Antwerp University Hospital, Edegem, Belgium.
Accepted for publication June 30, 2011.
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Presented at the Annual Scientific Meeting of the International Society for Minimally Invasive Cardiothoracic Surgery, June 16–19, 2010, Berlin, Germany.
Disclosure: The authors declare no conflict of interest.
Address correspondence and reprint requests to Els Van Dessel, MD, Department of Thoracic and Vascular Surgery, Antwerp University Hospital, Misstraat 162, Lier, 2500 Antwerpen, Belgium. E-mail: firstname.lastname@example.org.
Removal of ectopic parathyroid glands can be difficult due to their size and variable location, often not accessible by a cervical approach. When located in the mediastinum, morbidity by sternotomy or thoracotomy can be avoided by video-assisted thoracoscopic surgery (VATS); more recently, robotic systems were introduced. We present two cases of parathyroid glands located in the mediastinum and removed with the three-arm da Vinci robotic system.
We present a retrospective case series of two patients. The first case is a 34-year-old woman who reported headache, nausea, polyuria, fatigue, and emotional disturbances. Blood tests revealed an elevated serum calcium (11.4 mg/dL; normal value: 8.5 to 10.2 mg/dL) and elevated parathyroid hormone (PTH) levels (80 pg/mL; normal value: 13 to 54 pg/mL). Ultrasound suggested a small parathyroid adenoma caudally on the left side. A bilateral neck dissection was performed, but this showed four normal parathyroid glands. On computed tomographic (CT) scan of the thorax, a solitary nodule was seen in the anterior mediastinum, at the level of the aortic arch (Fig. 1a). This was confirmed by a sestamibi scintigraphic examination (Fig. 1b).
The second patient was a 66-year-old man with kidney stones, renal failure, and multiple brown tumors. Blood tests showed an elevated calcium (12 mg/dL) and PTH (1788 pg/mL) level. A CT scan showed a nodule in front of the aortic arch (Fig. 2a), which was confirmed by a sestamibi scintigraphic scan (Fig. 2b).
In both patients, a mediastinal parathyroidectomy with a three-arm da Vinci Robotic system was performed. The use of the da Vinci robot for the resection of tumors in the mediastinum, including the anterior compartment, was introduced in the Antwerp University Hospital in 2004. From January 2004 to December 2008, 36 consecutive patients with a surgical resectable, anterior mediastinal mass underwent a resection with the robot. We have no experience with VATS mediastinal surgery. The robot has been used to resect different kind of tumors including neurinomas, neurofibromas, mediastinal cysts, mediastinal metastases, ectopic parathyroid adenomas, and thymomas. The patients were placed in a supine position with a left 30-degree tilt by placing a silicon pillow under the left hemithorax. Four trocars were positioned in the left submammary fold (Fig. 3). The procedure was performed by two surgeons, three ports for the robotic system that are handled by the first surgeon at the console and one additional fourth trocar for the second surgeon at the operating table. These two surgeons had experience in both positions. The camera was placed in the central trocar while two ports were used for instruments, usually a Cadiere forceps and an electrocautery blade, and the fourth port served as an assistance for devices such as suction, retraction, and clipping. Single right lung ventilation was performed, and to improve the view, CO2 insufflation was performed at 7 mm Hg in the left hemithorax. Even with only moderate pressures (10–15 mm Hg), significant negative effects on circulation and ventilation may occur. Reduced venous return can cause hemodynamic instability, which was not present in our two patients.
We opened the mediastinum anterior to the left phrenic nerve. The mediastinal fat and thymic tissue were dissected up to the left brachiocephalic vein cranially. The mediastinal pleura was incised until the right parietal pleura was visible. Finally, the lower part of the mediastinum was dissected. In the second case, several branches of the left brachiocephalic vein were clipped. The resected nodules were removed en bloc using an endobag. A chest tube was left behind. (See Video 1, Supplemental Digital Content 1, at http://links.lww.com/INNOV/A8.) Both nodules had a positive sinking test and histologic examination confirmed the presumed diagnosis of a parathyroid adenoma. The operative times were 65 and 82 minutes, respectively. The set up time for the robot took approximately 20 minutes.
The chest tube was removed on the second postoperative day, and both patients left the hospital on the third postoperative day. The PTH levels were measured before incision, during manipulation of the adenoma, at 10 and 20 minutes after removal, and 1 day after the procedure. PTH levels decreased by half after removal of the lesions, and calcium levels dropped slightly below normal levels. Both patients received calcium supplements during the early postoperative weeks. There were no postoperative complications.
In 1% to 2% of cases, parathyroid adenomas are located in the mediastinum. In these circumstances, a standard cervical approach is difficult and often a sternotomy or thoracotomy is necessary for complete removal of the lesion. Because of their invasive character and higher morbidity rate, two alternative techniques were proposed. The first technique, angiographic ablation, has a high failure rate close to 40%.1,2 The second technique, VATS, has been broadly studied, and Alesina et al3 concluded that thoracoscopic parathyroidectomy is a safe and feasible technique. Because an ectopic adenoma is difficult to distinguish from its surrounding tissues, the success rate of this technique mainly depends on preoperative localization of the nodule. This is made possible by preoperative imaging techniques such as a sestamibi scintigraphic scan, magnetic resonance imaging, and CT scan. Compared with CT scan, the sensitivity of magnetic resonance imaging was higher but not as good as a 99Tc sestamibi scintigraphic scan. Radionuclide-guided dissection with a gamma probe in combination with VATS was successfully used by Ott et al4 but may confuse the surgeon when the lesion is located in the mediastinum because of accumulation of the radioisotope in the myocardium.5 As in classic approaches, quick intraoperative parathyroid assay can be an effective tool to confirm complete resection.6,7 An assay decline of 50% or higher compared with the highest preoperative level is considered successful, as was seen in our two patients.
Recently, the aid of the da Vinci Robotic system was introduced as a promising tool.8,9 The robot offers an answer for the disadvantages of a standard thoracoscopic approach. The 3D view, stable camera platform, and fine dissection with wrist-free mobility eliminate all these negative aspects and make the mediastinum, which is a delicate region to dissect, more accessible. Finally, we can conclude that the resection of mediastinal parathyroids with the da Vinci Robot is feasible, and it is our preferred technique for mediastinal locations.
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