US-guided microwave ablation for secondary hyperparathyroidism in patients after renal transplantation: a pilot study

Objective: To assess the safety and efficacy of ultrasound-guided microwave ablation (MWA) in the treatment of patients who develop secondary hyperparathyroidism (SHPT) after renal transplantation (RT).

Methods: In total, nine patients, each with symptomatic SHPT caused by RT and at least one enlarged parathyroid gland, underwent MWA via hydrodissection. Intact parathyroid hormone (i-PTH), serum calcium, serum phosphorus, creatinine and blood urea nitrogen concentrations, before and after MWA, were assessed and compared.

Results: Complete ablation was achieved in all patients for a total of 14 ablated parathyroid glands. The mean follow-up time was 17.2?±?1.7?months post-operation. The mean maximum diameter of the parathyroid glands was 1.3?±?0.4?cm (range: 0.4–2.0?cm). The ablation power implemented was 30?W and the mean time for each parathyroid gland to achieve complete ablation was 287.5?±?83.4?s. The mean i-PTH, serum calcium and phosphorus concentrations at one day post-MWA (69.6?pg/mL, 2.23?±?0.29?mmol/L, 1.2 2?±?0.48?mmol/L, respectively) were significantly lower than those before MWA (780.0?pg/mL, 2.62?±?0.32?mmol/L, 1.39?±?0.61?mmol/L, respectively; p?p?>?.05). No significant differences were found between the biomarker concentrations observed at one day post-MWA and at the follow-ups (p?>?.05). No major operation-related complications occurred.

Conclusion: Ultrasound-guided MWA is a safe and effective technique for destroying parathyroid gland tissue in patients who develop SHPT after RT and its clinical effects are long-lasting.