SUMMARY: Predominantly cystic thyroid nodules are often aspirated before radiofrequency ablation to enhance its efficacy; however internal bleeding during the aspiration is a problem. We evaluated the feasibility and safety of ethanol ablation to control internal bleeding that occurred during preparatory aspiration. Between September 2010 and August 2011, 11 of 40 predominantly cystic nodules bled internally during fluid aspiration before radiofrequency ablation. To control the bleeding, 99% ethanol was injected. The efficacy of ethanol in controlling bleeding, final nodule volume and complications were assessed. Control of the bleeding by ethanol ablation and subsequent radiofrequency ablation was feasible in all patients. Ninety-one percent (10/11) could be treated in 1 session. The mean nodule volume dropped from 17.1 to 4.3 mL (P < .018). There were no major complications. Ethanol ablation and radiofrequency ablation combination therapy is a feasible and safe technique for treating predominantly cystic thyroid nodules that exhibit internal bleeding during preparatory aspiration.
In our clinic, predominantly cystic thyroid nodules that bled internally after aspiration were injected with ethanol, after which they were subjected to RF ablation. The aim of this study was to evaluate the feasibility and safety of EA in controlling internal bleeding during aspiration of the internal fluid of predominantly cystic thyroid nodules before RF ablation.
All procedures were performed under US guidance. Intravenous sedatives or analgesics were not used before or during the procedure. The patients were placed in a supine position with mild neck extension. After skin sterilization and anesthesia with 2% lidocaine at the puncture site, a 16- or 18-ga needle was inserted into the cystic portion of the thyroid nodules through the isthmic area (this is the so-called transisthmic approach) to prevent leakage of fluid or ethanol.6,18,25 After the needle tip was placed into the cystic portion, as much of the internal fluid as possible was aspirated. If active bleeding was detected during the aspiration of the internal fluid, the aspiration was stopped and 99% ethanol was injected slowly into the cystic space to control the bleeding (On-line Video). The injected volume of ethanol corresponded to approximately 50% of the aspirated fluid volume. After 2 minutes of ethanol retention, as much of the injected ethanol as possible was removed.18 After real-time US confirmed that the bleeding had stopped, RF ablation was initiated. On the basis of previous experience, the RF ablation was performed by using a transisthmic approach and the moving-shot technique.6⇓–8,10,15,17,25⇓–27 For this, an 18-ga 7-cm-long monopolar modified internally cooled electrode (Well-Point RF electrode; Taewoong Medical, Kimpo, Korea or VIVA; STARmed, Gyeonggi, Korea) with a 1- or 1.5-cm active tip and a 200-W RF generator (VIVA RF Generator; STARmed) was used.
When RF ablation was started with the 11 patients, echogenic bubbles developed much faster than would normally occur. This phenomenon was due to the remnants of ethanol in the nodule that had diffused into the septate cystic portion (On-line Video). The moving-shot technique used for thyroid RF ablation7,8,10,28⇓–30 was first proposed by Baek et al,26 who suggested that the thyroid nodule should be divided into multiple conceptual ablation units that would each undergo RF ablation; this was achieved by moving the electrode tip. Because the conceptual units are smaller at the periphery of the nodule and larger in the center of the nodule, the electrode tip was initially positioned in the deepest, most remote portion of the nodule where there were no disturbances caused by microbubbles; this positioning facilitated the monitoring of the electrode tip. RF ablation was terminated when all conceptual units of the targeted nodule had changed into a transient hyperechoic zone. Adverse events during and immediately after the procedure were recorded. After RF ablation, the patient was observed for 1–2 hours in the hospital.
After EA, the active bleeding stopped in all patients and US confirmed that there was no blood collection within the thyroid nodule. The efficacy of RF ablation is summarized in the Table. The mean follow-up period was 11.4 ± 6.7 months (range, 6–24 months). The mean largest diameter decreased from 4.1 ± 1.3 cm (range, 2.4–7.1 cm) before treatment to 2.3 ± 0.6 cm (range, 1.3–3.0 cm) at the last follow-up (P = .003), and the mean volume dropped from 17.1 ± 16.9 mL (range, 2.9–59.0 mL) to 2.6 ± 2.1 mL (range, 0.2–6.9 mL) at the last follow-up (P = .005). At the 1-month, 6-month, and last follow-up visits, the mean volume reduction percentages were 52.9%, 75.6%, and 81.0%, respectively. Therapeutic success was achieved in all patients. The mean cosmetic score decreased from 4.0 before treatment to 2.8 ± 1.0 (range, 1–4) at the last follow-up (P = .01). The mean symptom score dropped from 2.7 ± 1.5 (range, 1–5) before treatment to 1.1 ± 1.0 (range, 0–4) at the last follow-up (P = .011). The follow-up US examinations indicated well-treated nodules that no longer had a cystic portion and whose echogenicity of the solid portion and intranodular vascularity was decreasing (Fig 1).
There were no major complications, such as voice changes, skin burn, hematoma, esophageal injury, tracheal injury, or infection, either during the procedure or in the follow-up period. During RF ablation, most patients reported pain and a sensation of heat in the neck that radiated to the head, shoulders, teeth, and chest. The symptoms were relieved by reducing the RF power or stopping the ablation for several seconds. All patients tolerated the RF ablation procedure well.
The present study showed that EA effectively controlled the postaspiration hemorrhage in all patients. The RF ablation, after bleeding control was achieved, significantly reduced the nodule volume and relieved the symptomatic and cosmetic problems. In addition, 91% (10/11) of the patients could be treated by 1 RF session, and there were no recurrences during the follow-up period. There were also no complications that related to the EA or RF ablation.
Initial nodule volume can be a risk factor for poor volume reduction by RF and the need for additional RF treatment sessions. Huh et al20 reported that an initial nodule volume larger than 20 mL required additional RF ablation to achieve satisfactory clinical results. Moreover, Jeong et al8 reported that thyroid nodules with a mean volume of 6.1 mL required an average of 1.4 treatment sessions, while Lim et al31 reported that thyroid nodules with a mean volume of 9.8 mL required 2.2 treatment sessions on average. These results indicate that smaller thyroid nodules can be treated with fewer sessions. In the present study, the mean nodule volume was larger (17.1 mL) than the mean volumes in the other RF studies (6.1–9.8 mL).8,31 Nevertheless, 91% (10/11) of patients could be treated in a single RF session; in addition, there were no recurrences during the mean follow-up period of 11.4 months. As a result, the mean treatment session number in this study was smaller (1.2) than the numbers in other studies (1.4–2.2). The present study differed from the preceding studies in that the internal fluid was aspirated to reduce the nodule volume with the aim of reducing the number of treatment sessions. The results indicate that this approach was successful. However, active bleeding can be triggered by the aspiration, and this can create an important technical problem: It can cause sudden enlargement of the thyroid nodule and the heat sink effect of the blood can make RF ablation ineffective. The present study showed that EA successfully controlled active bleeding during aspiration and that nodule volume was effectively reduced before RF ablation.
EA is a feasible and safe technique for controlling the active bleeding of predominantly cystic thyroid nodules that can occur when internal fluid is aspirated before RF ablation, allowing RF ablation to proceed in a single session in most instances.