Analysis of Factors Affecting Outcome of Ultrasound‐guided Radiofrequency Heat Ablation for Treatment of Primary Hyperparathyroidism in Dogs

Abstract

Radiofrequency (RF) parathyroid ablation is a noninvasive treatment for hyperparathyroidism in dogs. There are no published data assessing factors associated with RF parathyroid ablation success or failure in order to guide patient selection and improve outcome. The purpose of this retrospective analytical study was to determine whether imaging findings, biochemical data, or concurrent diseases were associated with RF heat ablation treatment failure. For inclusion in the study, dogs must have had a clinical diagnosis of primary hyperparathyroidism, undergone cervical ultrasound and RF ablation of abnormal parathyroid tissue, and must have had at least 3 months of follow-up information available following the date of ultrasound-guided parathyroid ablation. Dogs were grouped based on those with recurrent or persistent hypercalcemia and those without recurrent or persistent hypercalcemia following therapy. Parathyroid nodule size, thyroid lobe size, nodule location, and presence of concurrent disease were recorded. Recurrence of hypercalcemia occurred in 9/32 dogs that had ablation of abnormal parathyroid tissue (28%) and one patient had persistent hypercalcemia (3%) following parathyroid ablation. Nodule width (P = 0.036), height (P = 0.028), and largest cross-sectional area (P = 0.023) were larger in dogs that had recurrent or persistent hypercalcemia following ablation. Hypothyroidism was more common in dogs with recurrent disease (P = 0.044). Radiofrequency ablation was successful in 22/32 (69%) dogs. Larger parathyroid nodule size and/or concurrent hypothyroidism were associated with treatment failure in dogs that underwent ultrasound-guided RF parathyroid nodule ablation.

The Use of Percutaneous Ultrasound-Guided Radiofrequency Heat Ablation for Treatment of Primary Hyperparathyroidism in Eight Dogs: Outcome and Complications

“…The control of the hypercalcemia was achieved in 69 [15], 72 [13], 90 [14], and 94% [12] of the patients, respectively. The failure of the treatment can be explained by a wrong identification of the parathyroid nodule, inadequate ablation, or the ablation of nodules not secreting PTH [9,11,13]. Also, the importance of operator’s experience has been described [7,9].…”

“…The success rates are variable, according to different studies. In detail, parathyroidectomy is estimated to be successful in 94% of the treated cases, UG-RHA in 69% to 94%, and chemical/ethanol ablation in 72% to 85% [9,11,12,13,14]. Percutaneous UG-RHA and ethanol ablation are less invasive and usually require a shorter anaesthesia time than the surgical removal of the parathyroid lobe [4,13].…”

“…The dogs with small nodules (<2–3 mm) are poor candidates for this procedure, as needle insertion and manipulation can be difficult [4,13,15]. Also, dogs with large parathyroid nodules (>0.35 cm 2 of cross-sectional area) seem to have a higher rate of recurrence [11]. Consequently, in the cases where small or large nodules are detected, surgical intervention is still recommended.…”

“…Although UG-RHA has been increasingly performed in various referral centers, to our knowledge, only four studies have shown the advantages and disadvantages of this technique [11,12,13,14]. Consequently, information regarding their outcomes and complications is still scarce.…”

Diagnostische Aufarbeitung und Management der Hyperkalzämie des Hundes am Beispiel des primären Hyperparathyreoidismus

“…Da Ethanol aus dem Zielgewebe austreten und umgebende Strukturen schädigen kann, ist diese Therapieform nicht empfehlenswert. Potenzielle Komplikationen sind Husten, veränderte Stimmlage, unilaterale Larynxparalyse und Rezidivbildung (12,45). Eine gleichzeitig bestehende Hypothyreose konnte als Faktor für ein Therapieversagen identifiziert werden (12).…”