Bipolar Radiofrequency Ablation of the Adrenal Gland: In Vivo and Ex Vivo Experiments.

Laparoscopic adrenalectomy is currently the standard treatment modality for unilateral aldosterone-producing adenoma (APA); however, a less-invasive treatment is needed for its treatment. A new bipolar ablation system that poses a lower risk of complications has been recently developed. This study aimed to evaluate the safety and performance of a novel bipolar radiofrequency ablation (RFA) system for the treatment of APAs. Ablations were performed in an ex vivo study using bovine adrenal glands [group A: n = 6, single-probe; group B: n = 6, two probes, interprobe distance (ID) = 12 mm; group C: n = 6, two probes, ID = 20 mm]. The in vivo study was conducted in groups A and B (n = 2 each) using porcine adrenal glands. For the ex vivo study, the mean vertical diameter (Dv) of the coagulative necrosis area and the mean transverse diameter (Dt) values were 11.99 mm and 10.96 mm for group A, 12.66 mm and 10.0 mm for group B, and 23.37 mm and 22.10 mm for group C, respectively. For the in vivo study, the mean Dv and Dt values were 12.23 mm and 9.03 mm for group A, and 16.38 mm and 9.52 mm for group B, respectively. No heat-induced damage to the adjacent organs was observed. To our best knowledge, this is the first study to evaluate the performance of the bipolar system in RFA of the adrenal gland. RFA using the new bipolar ablation system is safe and produces a sufficient coagulation area to treat APAs.

The Potential of Computed Tomography Volumetry for the Surgical Treatment in Bilateral Macronodular Adrenal Hyperplasia: A Case Report.

Although adrenal resection is a major option to control hypercortisolemia in patients with bilateral macronodular adrenal hyperplasia, a predictive method for postoperative cortisol production has not been established. A 53-year-old man with ulcerative colitis was referred to our hospital for bilateral multiple adrenal nodules and hypertension. Physical and endocrinological examination revealed inappropriate cortisol production and suppressed secretion of adrenocorticotropic hormone with no typical signs of Cushing's syndrome. Imaging analysis revealed bilateral adrenal nodular enlargement, the nodules of which had the radiological features of adrenocortical adenomas without inter-nodular heterogeneity. In addition, computed tomography volumetry demonstrated that the left adrenal gland (70 mL) accounts for three quarters of the total adrenal volume (93 mL). The patient was diagnosed as subclinical Cushing's syndrome due to bilateral macronodular adrenal hyperplasia, and subsequently underwent a left laparoscopic adrenalectomy with the estimation of 75% decrease in the cortisol level based on the adrenal volume. The surgical treatment ultimately resulted in control of the cortisol level within the normal range, which was compatible to our preoperative prediction. However, regardless of the sufficient cortisol level, ulcerative colitis was exacerbated after the surgery, which needed a systemic therapy for remission. This case indicates successful surgical control of hypercortisolemia based on computed tomography volumetry in bilateral macronodular adrenal hyperplasia, as well as the perioperative exacerbation risk for inflammatory diseases in Cushing's syndrome. We report the potential utility of computed tomography volumetry as a quantitative method with retrospective evaluation of our historical cases.

Safety and feasibility of radiofrequency ablation using bipolar electrodes for aldosterone-producing adenoma: a multicentric prospective clinical study.

Evaluation of feasibility and safety of percutaneous radiofrequency ablation using bipolar radiofrequency devices in a prospective multicenter cohort of patients with benign aldosterone-producing adenoma. A total of five institutions participated. CT-guided percutaneous RFA was performed for patients diagnosed as APA. The safety of the procedure was evaluated using the Common Terminology Criteria for Adverse Events. During the 84-day follow-up period, serial changes in plasma aldosterone concentration and plasma renin activity were measured. The percentage of patients with normalized hormonal activity after the procedure, was calculated with 95% confidence intervals. Forty patients were enrolled, and two patients were excluded for cerebral hemorrhage and no safe puncture root. In another patients, RFA was tried, but an intraprocedural intercostal arterial injury occurred. Consequently, RFA was completed in thirty-seven patients (20 men, 17 women; mean age, 50.4 ± 10.0 year). The tumor size was 14.8 ± 3.8 mm. The treatment success rate of the ablation was 94.6% (35/37), and a 2nd session was performed in 2.7% (1/37) patients. Grade 4 adverse events were observed in 4 out of 38 sessions (10.5%). The normalization of plasma aldosterone concentration or aldosterone-renin ratio was 86.5% (72.0-94.1: 95% confidence interval) on day 84. Percutaneous CT-guided RFA for APA using a bipolar radiofrequency system was safe and feasible with clinical success rate of 86.5% on day 84.

Effect of a notch at the distal end of a microcatheter on vein deformation in segmental adrenal venous sampling: a preliminary study using computational fluid dynamics.

This study aimed to evaluate the effect of a notch at the distal end of a microcatheter on vein deformation in segmental adrenal venous sampling. A three-dimensional fluid-structure interaction simulation was performed using commercial finite element software. A computational model of a vein with a catheter inserted into it was constructed. The outer and inner diameters of the vein were 0.9 mm and 0.6 mm, respectively, whereas those of the catheter were 0.6 mm and 0.5 mm, respectively. The velocity of the blood flow at the outlet was 85 mm/s. The pressure at the inlet was 0 Pa. The mesh consisted of approximately 660,000 elements. The effect of the number (0-4) and shape (no notch, 1/4 circular, 1/3 circular, semicircular, 2/3 circlecircular, and 3/4 circular) of the notches at the distal end of the microcatheter on the vein deformation when a suction pressure was applied was evaluated. The venous wall displacement was the smallest with the one-notch catheter, followed by the four-notch catheter, and was the smallest with the catheter having 1/4-circular notches, followed by the one with 1/3-circular notches. In conclusion, microcatheters having one notch and 1/4-circular notches reduce vein deformation and lead to successful segmental adrenal venous sampling. Graphical abstract Comparing catheters having different notch shapes.