Rapid versus gradual bladder decompression in acute urinary retention.

OBJECTIVE: To demonstrate a benefit in diminished adverse events such as hypotension and hematuria with gradual drainage of the bladder when compared to rapid decompression in patients with acute urinary retention (AUR) due to benign prostatic hyperplasia in a case-control study. METHODS: Sixty-two patients matched our selection criteria presenting with AUR. They were divided into two groups - the first was managed by rapid drainage of the bladder, the second was managed by gradual drainage through a urethral catheter (The first 100 mL immediately evacuated, then the rest evacuated gradually over 2 h). RESULTS: The mean age was 64.4 and 63.2 years in the first and second group, respectively. Diagnosed cause was benign hyperplasia of the prostate. Hematuria occurred in two patients in the first group and none in the second group. The two cases of hematuria were mild and treated conservatively. After the relief of the obstruction, the mean blood pressure was noticed to decrease by 15 mmHg and 10 mmHg in the first and second group, respectively, however, no one developed significant hypotension. Pain relief was achieved after complete drainage in the first group and after the evacuation of 100 mL in the second group. CONCLUSIONS: We conclude that there is no significant difference between rapid and gradual decompression of the bladder in patients with AUR. Hematuria and hypotension may occur after rapid decompression of the obstructed urinary bladder, but these complications are rarely clinically significant.

Management of lower ureteric stones: a prospective study.

OBJECTIVE: To discuss the current concepts in lower ureteric stone management. MATERIAL AND METHODS: Between October 2008 and November 2010, 190 patients of both sexes and of different age groups with lower ureteric stones, underwent in situ extracorporeal shock wave lithotripsy (ESWL) (48 cases), ureterorenoscopy (URS) (120 cases) and open stone surgery (OSS) (22 cases). The patients' clinical and radiological findings, as well as stone characteristics, were reviewed and correlated with the stone-free status. RESULTS: In the ESWL group, the operative time was 43.13 +22.5 min; the average number of sessions/patients was 1.5 sessions; the average number of SW/patients was 4500 SW/patients; the average energy was 16.5 kV; the average stone burden was 7.8/mm; the overall stone-free rate was 75% (36/48); and the average radiation exposure time was 3.5 min. In the URS group, the operative time was 49.21 +16.09 min; the average stone burden was 10.81mm; the overall stone-free rate was 97.5% (117/120); the average hospital stay was 3.99 days; and the average radiation exposure time was 0.75 min. In the OSS group, the operative time was 112.38 +37.1 min; the overall stone-free rate was 100% (22/22); and the average hospital stay was 9.74 days. CONCLUSION: In the management of patients with lower ureteral stones, URS, SWL and OSS were considered acceptable treatment options. This recommendation was based on the stone-free results, morbidity and retreatment rates for each therapy.

Ex vivo model for renal fracture in cryoablation.

OBJECTIVE: To demonstrate the formation of fractures due to cryoablative therapy in a controlled model and validate the new model for the study of the complication of fractures during renal cryoablation. METHODS: Endocare PERC-17 (1.7 mm) and Galil 17 ga IceRod (1.47 mm) probes were selected because of similar diameter and reported ice-ball size. The ex vivo model used here was a porcine kidney obtained at the supermarket. The kidneys were subsequently bivalved. The cryoprobes were inserted running just underneath the cut surface, entering the lateral surface of the kidney, and directed toward the medial surface of either the upper or lower pole. In this manner, we avoided the major calyces and involved the most parenchyma. Freeze-thaw-freeze cycles of various durations were performed. The probes were frozen parallel to each other at a distance of 20 mm apart. RESULTS: Evidence of cryoablation-induced fracture included popping sounds noted during thaw and cracks that became visible during the phase of second freeze. Cracks were noted to extend from the probe through the parenchyma. In multiple probe freezes, the intervening zone between the 2 ice-balls had smoother ice and the fractures that appeared there originated at either probe. Fracture formation was only observed with the Endocare probes, with single or parallel freezes. No fractures were noted in the IceRod freezes. CONCLUSION: The bivalved ex vivo kidney is an inexpensive, representative, and demonstrative model for study of fracture during cryoablation.

An in vivo evaluation of a novel spiral cut flexible ureteral stent.

OBJECTIVE: The flow characteristics, ureteral conformance, and histopathologic changes of a novel spiral cut flexible ureteral stent (Percuflex Helical, Boston Scientific, Boston, MA) were evaluated in vivo in an acute and chronic porcine model. MATERIALS AND METHODS: Flow characteristics and ureteral conformance of the novel stent were determined in 6 acute and 6 chronic swine models and compared with a control ureteral stent (Percuflex Plus, Boston Scientific). The flow characteristics were determined in vivo after ligating the renal vessels and via a nephrostomy tube delivering a standard rate of 0.9% saline at 35 cm H(2)O. Flows in the unobstructed ureter, normal stent, intraluminally obstructed stent, extraluminal obstructed stent, and both intraluminally and extraluminally obstructed conditions were determined. In the chronic animals, flow was determined at day 10, with the stent in place and immediately after stent removal. Conformance and hydronephrosis was assessed on pyelograms. Histopathologic changes were also evaluated in the chronic animals. RESULTS: The acute and chronic flow characteristics in the novel stent were equivalent to the control stent. Size and weight of the kidney, degree of hydronephrosis, stent migration, and presence of urinary tract infection were also similar between the test and control stents. There were no differences seen in histopathologic grading or degree of encrustation in either stent. The novel stent appeared to conform better to the shape of the ureter in both acute and chronic animals. CONCLUSION: The novel helical stent appears to drain as well as a standard stent and causes no increased degree of histopathologic changes in the ureter.

Are multiple cryoprobes additive or synergistic in renal cryotherapy?

OBJECTIVE: To investigate the relationship between multiple cryoprobes was investigated to determine whether they work in an additive or synergistic fashion in an in vivo animal model because 1.47 mm (17-gauge) cryoprobes have been introduced to the armamentarium for renal cryotherapy. METHODS: Laparoscopic-guided percutaneous cryoablation was performed in both renal poles of 3 pigs using 3 IceRod cryoprobes. These 12 cryolesions were compared with 12 cryolesions using a single IceRod cryoprobe. Each cycle consisted of two 10-minute freeze cycles separated by a 5-minute thaw. The iceball volume was measured using intraoperative ultrasonography. The kidneys were harvested, and cryolesion surface area was calculated. The lesions were fixed and excised to obtain a volume measurement. Statistical analysis was used to compare the single probe results multiplied by 3 to the multiple probe group for iceball volume, cryolesion surface area, and cryolesion volume. RESULTS: The iceball volume for the first freeze cycle for the single cryoprobe multiplied by 3 was 8.55 cm3 compared with 9.79 cm3 for the multiple cryoprobe group (P=.44) and 10.01 cm3 versus 16.58 cm3 for the second freeze (P=.03). The cryolesion volume for the single cryoprobe multiplied by 3 was 11.29 cm3 versus 14.75 cm3 for the multiple cyroprobe group (P=.06). The gross cryolesion surface area for the single cryoprobe multiplied by 3 was 13.14 cm2 versus 13.89 cm2 for the multiple probe group (P=.52). CONCLUSION: The cryolesion created by 3 simultaneously activated 1.47-mm probes appears to be larger than that of an additive effect. The lesions were significantly larger as measured by ultrasonography and nearly so (P=.06) as measured by the gross cryolesion volume.

Optimal freeze cycle length for renal cryotherapy.

PURPOSE: To our knowledge the optimal freeze cycle length in renal cryotherapy is unknown. Ten-minute time based freeze cycles were compared to temperature based freeze cycles to -20C. MATERIALS AND METHODS: Laparoscopic renal cryotherapy was performed on 16 swine. Time based trials consisted of a double 10-minute freeze separated by a 5-minute thaw. Temperature based trials were double cycles of 1, 5 or 10-minute freeze initiated after 1 of 4 sensors indicated -20C. A 5-minute active thaw was used between freeze cycles. Control trials consisted of cryoneedle placement for 25 minutes without freeze or thaw. Viability staining and histological analysis were done. RESULTS: There was no difference in cellular necrosis between any of the temperature based freeze cycles (p = 0.1). Time based freeze cycles showed more nuclear pyknosis, indicative of necrosis, than the 3 experimental freeze cycles for the renal cortex (p = 0.05) but not for the renal medulla (p = 0.61). Mean time to -20C for freeze cycle 1 was 19 minutes 10 seconds (range 9 to 46 minutes). In 4 of 21 trials (19%) -20C was never attained despite freezing for 25 to 63 minutes. CONCLUSIONS: There was no difference in immediate cellular necrosis among double 1, 5 or 10-minute freeze cycles. Cellular necrosis was evident on histological analysis for trials in which -20C was attained and in freeze cycles based on time alone. With a standard 10-minute cryoablation period most treated parenchyma 1 cm from the probe never attained -20C. Cell death appeared to occur at temperatures warmer than -20C during renal cryotherapy.

Sprayed fibrin sealant as the sole hemostatic agent for porcine laparoscopic partial nephrectomy.

PURPOSE: Tisseel® is used to control minor bleeding during laparoscopic procedures. The DuploSpray MIS™ spray system allows thin, even application over a larger surface area. We use sprayed Tisseel as the sole agent to control hemorrhage and seal the renal collecting system after severe porcine laparoscopic partial nephrectomy. METHODS AND MATERIALS: We performed staged bilateral severe laparoscopic partial nephrectomy in 12 Yucatan pigs using a longitudinal cut from upper to lower pole through the entire collecting system. In each pig 1 kidney was harvested immediately while the other was harvested after 4 weeks. After hilar clamping laparoscopic partial nephrectomy was done with cold scissors in 6 pigs while LigaSure™ was used in the other 6. Sprayed Tisseel was applied, and bleeding and urinary leakage were evaluated. Additional Tisseel was applied for repeat bleeding. We performed retrograde pyelogram (chronic) and burst pressure testing of the arterial and collecting systems. RESULTS: All animals survived 4 weeks. One urinoma was seen on retrograde pyelogram in the cold cut group. Average hilar clamp time was similar in the acute and chronic study arms. Average estimated blood loss was significantly less in the LigaSure group (p = 0.0045). Average arterial burst pressure was significantly different in the chronic and acute groups (605.8 vs 350.4 mm Hg, p = 0.008) but average collecting system burst pressure was similar (186.3 and 149.5 mm Hg, respectively). CONCLUSIONS: Sprayed Tisseel without suturing effectively sealed the arterial and collecting system after severe laparoscopic partial nephrectomy in the porcine model.

In vitro, ex vivo and in vivo isotherms for renal cryotherapy.

PURPOSE: Preoperative planning for renal cryotherapy is based on isotherms established in gel. We replicated gel isotherms and correlated them with ex vivo and in vivo isotherms in a porcine model. MATERIALS AND METHODS: PERC-17 CryoProbes (1.7 mm) and IceRods (1.47 mm) underwent trials in gel, ex vivo and in vivo porcine kidneys. Temperatures were recorded at 13 predetermined locations with multipoint thermal sensors. RESULTS: At the cryoprobe temperatures were not significantly different along the probe in any medium for either system (p = 0.0947 to 0.9609). However, away from the probe ex vivo and in vivo trials showed warmer temperatures toward the cryoprobe tip for each system (p = 0.0003 to 0.2141). Mean +/- SE temperature 5 mm distal to the cryoprobe tip in vivo was 19.2C +/- 16.1C for CryoProbes and 27.3C +/- 11.2C for IceRods. Temperatures were consistently colder with CryoProbes than with IceRods in gel (p <0.00005), ex vivo (p <0.00005) and in vivo (p = 0.0014). At almost all sites temperatures were significantly colder in gel and in ex vivo kidney than in in vivo kidney for CryoProbes (p = 0.0107 and 0.0008, respectively) and for IceRods (each p <0.00005). CONCLUSIONS: Gel and ex vivo isotherms do not predict the in vivo pattern of freezing. Thus, they should not be used for preoperative planning. The cryoprobe should be passed 5 mm beyond the tumor border to achieve suitably cold temperatures. Multipoint thermal sensor probes are recommended to record actual temperature during renal cryotherapy.

Impact of pneumoperitoneum on renal cryotherapy.

PURPOSE: Pneumoperitoneum is known to decrease blood flow to the kidney during laparoscopy. We investigated if this change in blood flow would increase the size of the cryolesion. MATERIALS AND METHODS: Twelve Yorkshire swine underwent laparoscopy-guided percutaneous cryoablation of the upper and lower pole of each kidney at four randomized pneumoperitoneum pressures (10, 15, 20, and 25 mm Hg). Cryolesions were made with a 1.47-mm IceRod (Galil Medical, Plymouth Meeting, PA). Each site underwent two 10-minute freeze cycles separated by a 5-minute active thaw with pressurized helium gas. At the conclusion of each freeze cycle, the iceball volume was measured with intraoperative ultrasound. After completion of the four cryolesions, the kidneys were harvested, and the cryolesion surface area was calculated. The lesions were fixed in 10% buffered formalin and then excised with a 1-mm margin to obtain a volume measurement using fluid displacement. RESULTS: Iceball volume was 3.41, 2.85, 3.44, and 2.36 cm(3) for freeze cycle 1 (p = 0.16) and 3.67, 3.34, 4.88, 3.95 cm(3) for freeze cycle 2 (p = 0.20) at 10, 15, 20, and 25 mm Hg, respectively. Cryolesion volume by fluid displacement was 4.06, 3.77, 3.97, and 3.93 cm(3) (p = 0.86) and cryolesion surface area was 4.55, 4.38, 4.39, and 4.20 cm(2) (p = 0.71) at 10, 15, 20, and 25 mm Hg, respectively. CONCLUSIONS: In this study, pneumoperitoneum pressure between 10 and 25 mm Hg did not affect iceball size as measured by intraoperative ultrasound, cryolesion volume by fluid displacement, or cryolesion surface.