Parathyroid Nodule Thermal Ablation

Background and indications

Primary hyperparathyroidism is a common condition (1-3% of the population), most often caused by a single parathyroid adenoma. It causes hypercalcemia leading to fatigue, bone pain, kidney stones, and neuropsychiatric symptoms. Surgery (parathyroidectomy) is the reference treatment, but ultrasound-guided thermal ablation (radiofrequency or microwave) is a minimally invasive alternative for patients with high surgical risk, post-surgical recurrence, or those declining surgery.

Pre-procedure assessment

Assessment includes complete phospho-calcium panel (calcium, PTH, phosphorus, vitamin D, 24h calciuria), cervical ultrasound localizing the adenoma, MIBI scintigraphy confirming localization, and ENT vocal cord examination. Concordance between ultrasound and scintigraphy is desirable.

Procedure

Under local anesthesia and sedation, a radiofrequency electrode or microwave antenna is inserted into the parathyroid adenoma under ultrasound guidance. Hydrodissection protects the recurrent nerve and adjacent thyroid. The nodule is treated using the "moving shot" technique. Intra-procedural PTH measurement may verify treatment efficacy. The procedure takes 20 to 40 minutes.

Results and scientific evidence

Published series show a 70-90% calcium and PTH normalization rate after parathyroid adenoma thermal ablation (Wei et al., International Journal of Hyperthermia, 2021; DOI: 10.1080/02656736.2021.1933213). Adenoma volume reduction is 60-80% at 6 months. Recurrence rate is approximately 10-15% at 2 years, with retreatment possibility.

Risks and complications

Transient voice change (2-5%, usually complete recovery), local pain (20-30%), cervical hematoma (< 3%). Permanent recurrent nerve injury is rare (< 1%). Transient post-procedural hypocalcemia is possible but rare (< 5%), unlike surgery where it is more common.

Recovery

Return to activities the following day. Calcium and PTH monitoring at D1, D7, then at 1, 3, 6, and 12 months. Ultrasound follow-up at 3 and 6 months.

Practical information

The procedure is performed as an outpatient or short inpatient stay depending on the case. It is performed by a specialized interventional radiologist, in coordination with the endocrinologist.