The current cryoablation equipment has the ultrasound probe incorporated in the cryo-equipment and system. The ultrasound probe in the standard technique is supported by the operator, but it is possible to use a stepper to keep the probe in place, letting the surgeon’s hands free. The stages of cryoablation are summarized in Table 31.1.

Once diameters of the gland have been measured, the ultrasound images’ setting is completed in axial and longitudinal views. Six to ten cryoprobes are inserted in the prostate gland under ultrasound control through perineal pathway (Fig. 31.3). Three to five cryoprobes are inserted in each side depending on the prostate volume, anatomy, and freezing power of cryoprobes that depends on technology and diameter (from 3 or 1.7 mm) (Fig. 31.4). The operating table is set in flat position without inclinations or Trendelenburg position. The procedure takes place with distended bladder (>250 ml) with urethral Foley catheter. The cryoprobes are positioned in order to cover uniformly the gland with temperatures at least below −20 °C and extend their effect to some mm beyond the capsule [6, 9]: whole-gland treatment therefore does not provide a nerve-sparing technique. Subsequently we proceed to the insertion of thermocouples: in the soft tissue close to the capsule at the basal level bilaterally and in the subcapsular prostatic tissue in the apex, one additional thermometer is placed in the external urethral sphincter in the median and suburethral position. From three up to six thermometers can be used. Any additional thermal sensors are positioned in order to evaluate the effect of the freezing process in a target area and to monitor the integrity of the external sphincter muscle. The thermometers are positioned in key points, at the edges of the gland to ensure homogeneous and complete ablation reaching target temperatures. Temperature control and ultrasound images provide the operator with an important feedback during the freezing procedure stages.

The urethroscopy is necessary in the learning phase or if a transperineal grid to place cryoprobes has been used. A flexible urethroscopy is useful to verify whether the cryoprobes are not penetrated into the lumen of the urethra, while insertion in the bladder is avoided using ultrasound control. At this stage, some surgeons insert a suprapubic catheter as an alternative to transurethral catheter. In our experience with the freehand technique, the ultrasound control is sufficient to exclude accidental transurethral placements [10]. We do not use routinely the suprapubic catheter.

Once the cystoscope is unthreaded, the guidewire is inserted on the warming catheter at 37° (called urethral warmer) which is useful to avoid damage of the urothelium and mucosa of the prostatic urethra. Leaving viable mucosa on the prostatic urethra prevents the urethral necrosis that is also called sloughing syndrome.

The freezing process begins with the activation of the gas Argon in the cryoprobes, starting from the anterior ones and then activation of probes located in the posterior/peripheral zone. This procedure aims to create an ice ball that gradually joins and reaches the peripheral area and incorporates the capsule. It is easy to monitor the freezing process by ultrasound, because the ice reflects the ultrasounds and appears as a thin, sharp hyperechoic edge with dark posterior acoustic shadow (Fig. 31.5). The temperature at the level of the hyperechoic edge of the ice ball is equal to the freezing water (0°/−5 °C). The ice growing is ultrasound monitored both in axial and longitudinal planes until the posterior capsule, the apex, and the base are covered by the hyperechoic edge. Meanwhile the freezing power is modulated in order to avoid an excessive increase toward the sphincter and Denonvillier’s fascia on the rectum. The Denonvillier’s fascia which covers the rectal adventitia is recognizable by ultrasound and should be always free from the ice ball edges (Figs. 31.6, 31.7, and 31.8). The first freezing cycle reaches temperatures about −40°/−20 °C in target areas for at least 5 min. Once the first cycle has been completed, it starts the heating stage of cryoprobes by activating the circulation of the helium gas; this stage takes 15 min. The ultrasound monitoring shows during this phase the almost complete disappearance of the ice ball, and the glandular parenchyma comes back visible, as well as temperatures return all above zero. The second freezing cycle takes place right after and takes altogether 15 min reaching the target temperatures. In the end, the cryoprobes are heated to allow an easy removal and are unthreaded. A compressive dressing is applied on the perineum. Finally the urethral warming catheter is removed, which is then replaced by a transurethral catheter using an hydrophilic guide. The time for the bladder catheter removal is about 2 weeks. If the suprapubic catheter was inserted, spontaneous voiding is encouraged after 1 or 2 weeks, and it will be removed soon after the post-voiding residual urine will be less than 50 cc.