Interventional Ultrasound: Puncture and Sclerotherapy of Renal Cysts

Fig. 15.1

Acute hemorrhage after ultrasound-guided puncture of simple renal cysts (power Doppler)

As regards the technique used to treat simple renal cysts, the method most commonly adopted is the Seldinger that involves first of all puncture of the cyst with an 18-gauge needle under US guidance, after administering local anesthetic with or without an associated systemic painkiller. Subsequently, a guidewire is placed, and dilators of increasing caliber are inserted until the passage is sufficiently wide to position a nephrostomic catheter. Patient preparation for this procedure includes associated antibiotic prophylaxis. Percutaneous puncture of the cyst can be done via posterior or posterolateral access depending on its anatomical position. After the drainage catheter has been positioned inside the cyst cavity and secured in place with silk stitches, the cyst content is aspirated [7]. After aspiration, we believe it is important for safety reasons to fill the cyst cavity firstly with 60 ml of physiological solution that is completely re-aspirated after a few minutes, to confirm the integrity of the cyst wall. Then ethanol is instilled at a quantity equal to 30 % of the previously drained liquid (generally never more than 60 ml). The patient is asked to change the decubitus position frequently, and then, after 40 min, the alcohol is completely re-aspirated and the transcutaneous catheter is removed [8]. In rare cases (of very voluminous cysts), this procedure can be repeated after an interval of 24 h (leaving the nephrostomic catheter in situ) [5].

15.3 Outcome and Complications

In literature, a number of reports have been published claiming that the procedure needs to be performed two or three times in order to achieve a complete remission of the clinical picture. Nevertheless, the results, expressed in terms of lack of recurrence, are heterogeneous, and in many experiences, a single treatment guaranteed a comparable outcome to repeated sclerosing (Table 15.1). The success of the treatment seems to depend on how long the ethanol remains in contact with the cyst walls. The authors who performed more than one treatment preferred not to exceed 20 min contact, while in more recent experiences, a single sclerosing session prolonged for 40/60 min yielded a satisfactory outcome with a comparable rate of complications [9].

Table 15.1

Sclerosing treatment of renal cysts