10.1245/s10434-006-9180-z
Annals of Surgical Oncology 13:1690-1695 (2006)
© 2006 Society of Surgical Oncology
Sonographically Guided Fine Needle Aspiration with Rapid Parathyroid Hormone Assay
Christina Maser, MD1,
Patricia Donovan, RN BSN1,
Florie Santos, CASCP2,
Richard Donabedian, MD2,
Christine Rinder, MD3,
Leslie Scoutt, MD4 and
Robert Udelsman, MD, MBA1
1 Department of Surgery, Yale New Haven Hospital, Yale University School of Medicine, 330 Cedar Street, FMB 102, P.O. Box 208062, New Haven, CT 06520-8062, USA
2 Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, USA
3 Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, USA
4 Department of Diagnostic Imaging, Yale University School of Medicine, New Haven, CT, USA
Correspondence: Address correspondence and reprint requests to: Robert Udelsman, MD, MBA, FACE; E-mail: robert.udelsman{at}yale.edu
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ABSTRACT
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Background: Persistent or recurrent primary hyperparathyroidism (1° HPTH) is ideally treated with limited dissection, based on accurate localization, to minimize operative risks. To accurately localize parathyroid tissue, we employed ultrasound-guided fine needle aspiration (US FNA) with an on-site rapid parathyroid hormone (PTH) assay to confirm localization.
Methods: Of the 272 patients evaluated for 1° HPTH, 34 had persistent or recurrent disease. Standard localization was equivocal in 12, who were referred for US FNA. Suspicious tissue was identified on US and FNA was performed. Analysis with a rapid PTH assay provided on-site result within 12 min. Patients were monitored clinically, and then discharged after observation.
Results: Twelve patients were referred for US FNA; eight were female. Ten patients had persistent disease, one had recurrent, and one had 1° HPTH following thyroidectomy. Two of the 12 were excluded due to negative ultrasound examination. Of the remaining ten, positive aspirates were found in nine, and seven proceeded to surgery. In six patients there was 100% correlation between sonographic and operative findings. The remaining patient had no identifiable adenoma, but PTH normalized after arterial ligation. All patients received a limited directed surgical approach, employing cervical block anesthesia in three. Four were discharged on the day of surgery and all were cured. There was one infectious complication of US FNA.
Conclusions: The use of rapid PTH assay can be effectively utilized for localization of parathyroid tissue in remedial parathyroid surgery. Confirmation of localization markedly improves subsequent surgery and allows selective use of minimally invasive techniques.
Key Words: Hyperparathyroidism • Parathyroidectomy • Localization • Remedial surgery • Parathyroid hormone assay
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INTRODUCTION
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Primary hyperparathyroidism (1° HPTH) is successfully treated by surgery in 95–98% of cases.1–4 The small subset of patients that present with either persistent or recurrent 1° HPTH represent a difficult clinical scenario. Re-exploration in these patients is associated with an increased risk of peri-operative morbidity.5 Accordingly, these patients require accurate pre-operative localization to allow for a focused surgical approach to minimize the risks associated with remedial surgery.
Localization tests, including sestamibi scanning and ultrasound (US), can be equivocal in the remedial setting, and further imaging is frequently required. Computed tomography (CT) and magnetic resonance imaging (MRI) can provide adjunctive information, but are often non-informative, misleading, or discordant. It is often necessary to proceed to venous localization which appears to be the most sensitive localization technique in the remedial setting.6,7 While helpful, it is also invasive and costly.
In an effort to provide accurate and less invasive localization, the use of US combined with fine needle aspiration (FNA) has been investigated.8–10 Measurement of parathyroid hormone (PTH) levels in suspicious tissue, and also performing cytological analysis have been reported; however, there is a significant delay between testing and result. This can limit the usefulness of testing as thyroid nodules and lymph nodes are frequently encountered and can lead to negative FNA results several days after testing was performed. We have previously employed the rapid PTH assay during venous localization testing to provide rapid results in an effort to improve the accuracy of testing.6 Providing real-time feedback employing an assay with a 12 min turnaround time allows the angiographer to adjust their testing. This reliable information can confirm a subtle gradient or terminate a positive study. Accordingly, to improve the accuracy of US in the re-operative neck, we investigated the use of a rapid PTH assay to immediately analyze results obtained from US guided FNA.
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METHODS
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Between May 2003 and May 2005, 272 patients were evaluated for 1° HPTH. Of these, 238 had not been explored and underwent de novo exploration. Of the remaining patients, 33 had persistent or recurrent 1° HPTH, and one developed 1° HPTH in the setting of previous thyroidectomy. Localization testing with sestamibi, ultrasound, CT, and venous localization was positive in 22, and these patients went directly for operative intervention. The remaining 12 had equivocal localization; however, they all had suspicious findings on US. These patients were referred for US FNA employing rapid PTH assay.
A dedicated sonographer performed a diagnostic study, and after identification of tissue suspicious for an abnormal parathyroid gland, consent was obtained for FNA. The FNA was performed using a 25 gauge needle under sterile technique and direct US guidance to aspirate the suspicious tissue into a 3 cc syringe containing 1 cc of saline. With the saline present in the syringe, appropriate negative pressure was applied in the standard fashion. The saline was then flushed through the needle containing the specimen into a specimen tube and the resultant solution was analyzed for PTH on site using the portable Nichols intact parathyroid hormone assay (Nichols diagnostics, San Juan Capistrano, CA, USA) in the ultrasound suite. This assay provides a result within 12 min, and depending on the findings, further passes through abnormal tissue were made. Patients were monitored for complications and discharged after 1 h of uneventful observation. Surgical intervention followed on an elective basis.
Data were collected prospectively and included patient demographics, diagnostic work-up, decision making, ultrasound results, operative findings, length of stay, and long-term follow up.
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RESULTS
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Twelve patients were referred for US FNA; eight female, four male. The mean age was 58.3 years (range = 38–74 years). Ten patients had persistent disease, one had recurrent 1° HPTH, and 1 developed 1° HPTH after previous thyroid surgery. Symptoms consisted of fatigue in six, mental status or mood changes in three, constipation in one patient, and nine patients had signs of the disease including seven with osteopenia/osteoporosis, and two with nephrolithiasis.
Pre-operative imaging was carried out with a combination of modalities. Sestamibi scanning was performed in 11 of these patients and was positive but discordant with the operative history in 8, and negative in the remaining 3. However, all 12 patients underwent an initial diagnostic ultrasound study demonstrating an abnormality suspicious for parathyroid tissue. In two of these patients, the abnormality could not be reproduced at the time of proposed aspiration; these patients underwent venous localization and were excluded from this analysis. Additionally, some patients had adjunctive imaging with CT, MRI, and PET; however these studies were inconsistently obtained and thus not considered in the final analysis.
Of the ten patients with sonographic abnormalities amenable to aspiration, positive results were obtained in nine. In these nine patients with positive aspiration results, two are pending operative intervention, and seven have proceeded to operation. In six of these patients there was 100% correlation between sonographic and operative findings; see Fig. 1
. Details of the aspiration procedures and operative findings are depicted in Table 1. On average, four passes (range 2–9) were made in each patient. Each suspicious lesion was interrogated and the PTH result was deemed positive if the result was higher than normal range (6–40 pg/ml) on our assay; the result was considered negative if less than 40 pg/ml. Most cases revealed an ‘off scale’result meaning that the result was greater than 1,000 pg/ml; these were unequivocally positive. Two patients had results in the 49–65 pg/ml range which represented questionably positive results. One of these patients was found to have a large retroesophaeal adenoma correlating to the ultrasound abnormality, and the other has not yet undergone operative intervention. One patient had no identifiable adenoma at operation despite an ‘off scale’result during aspiration. This patient underwent an extensive exploration, including a formal central neck dissection in the setting of a previous subtotal thyroidectomy. Five specimens were removed; three lymph nodes, and two fragments of soft tissue. Biochemical cure with normalization of the intra-operative PTH was reached after ligation of the inferior thyroid artery; the patient remained normocalcemic at long-term follow-up.
Received for publication May 23, 2006.
Accepted for publication May 23, 2006.
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ABSTRACT
INTRODUCTION
