Donald L. Pick

The impact of cavernosal nerve preservation on continence after robotic radical prostatectomy

Study Type – Therapy (case series)

Robotic Pyeloplasty: The University of California-Irvine Experience

PURPOSE For the treatment of ureteropelvic junction obstruction laparoscopic dismembered pyeloplasty and open pyeloplasty have similar outcomes. We present our experience with robot assisted laparoscopic dismembered pyeloplasty. MATERIALS AND METHODS We retrospectively reviewed all adult robot assisted laparoscopic dismembered pyeloplasties performed at our institution between November 2002 and July 2009. Preoperative evaluation included abdominal computerized tomography angiogram to assess for crossing vessels and diuretic renal scan to quantify the degree of obstruction. Followup with diuretic renal scan and a patient pain analog scale was performed 3, 6 and 12 months after surgery. If the study was normal at 12 months, the patient was followed with ultrasound of the kidneys and bladder to look for ureteral jets. Absent ureteral jets, worsening hydronephrosis or patient complaint of pain necessitated repeat diuretic renogram. RESULTS A total of 61 robot assisted laparoscopic dismembered pyeloplasties were performed in 21 men and 40 women. Followup was available for 57 patients with an average ± SD age of 35 ± 16 years and average followup of 18 ± 15 months. Mean operative time was 335 ± 88 minutes and estimated blood loss was 61 ± 48 ml. Average hospitalization time was 2 ± 0.9 days and the average postoperative analgesia requirement was 13 ± 9.6 mg morphine sulfate equivalents. The overall success rate was 81% based on a normal diuretic renogram and lack of pain using a validated pain scale. There were 3 grade III Clavien complications for a 4.9% major complication rate. CONCLUSIONS Robot assisted laparoscopic dismembered pyeloplasty is a feasible technique for ureteropelvic junction reconstruction. When measured by the more stringent application of diuretic renography and analog pain scales, the success rate for ureteropelvic junction obstruction management appears similar to that of open or standard laparoscopic approaches.

Prospective randomized trial of three different methods of nephrostomy tract closure after percutaneous nephrolithotripsy

Study Type – Therapy (RCT) 
Level of Evidence 1b

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.

Differences in Grip Forces Among Various Robotic Instruments and da Vinci Surgical Platforms

INTRODUCTION The da Vinci surgical platform is becoming increasingly available and utilized. Due to the lack of haptic feedback, visual cues are necessary to estimate grip forces and tissue tensions during surgery. We directly measured the grip forces of robotic EndoWrist instruments using the three available da Vinci robotic surgical platforms. METHODS Robotic instruments were tested in the da Vinci S, Si, and Standard systems. A load cell was placed in a housing unit that allowed for measurement of the grip forces applied by the tip of each robotic instrument. Each instrument was tested six times, and all data were analyzed using Students t-tests or analysis of variance when appropriate. RESULTS Slight differences in grip force were seen when the instrument was tested through 2 degrees of freedom at the tip (p = 0.02, analysis of variance) and when comparing a new instrument to an older instrument (p = 0.001 at the neutral position). There was no statistical difference in grip force between the left and right robotic arms. There was a broad range of grip forces between the various robotic instruments. The lowest grip force was registered in the double fenestrated grasper (2.26 ± 0.15 N), whereas the highest was seen in the Hem-o-lok clip applier (39.92 ± 0.89 N). In comparison to the S and Si, the Standard platform appeared to have significantly higher grip forces. CONCLUSION Different grip forces were observed among the various robotic instruments commonly used during urologic surgery and between the Standard and the S and Si platforms.

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.

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.

First prize: Chitosan and the urothelial barrier: effects on ureteral intraluminal drug penetration and peristalsis.

INTRODUCTION Relaxing the ureter prior to endourologic procedures could ease instrument access. In an ex-vivo model, intraluminal nifedipine has been shown to relax the ureter. Chitosan is the deacetylation product of chitin and can alter bladder urothelium. This study examines the effect of nifedipine on peristalsis before and after pretreating the ureter with chitosan. METHODS Intact 4-cm tubular porcine ureteral segments were placed in a novel organ bath. To induce peristalsis, phenylephrine (10 μM) was added. Chitosan (0.5% [w/v], 30 minutes) or Krebs (control) was then used to treat the urothelium. The rate and amplitude of ureteral peristalsis was then measured. Intraluminal nifedipine (1 μM) was then added to the intraluminal reservoir. Peristaltic rate and amplitude and the time to aperistalsis were measured. Methylene blue was then added after treatment with chitosan or control to measure diffusion. RESULTS After Krebs pretreatment, intraluminal nifedipine (1 μM) significantly reduced peristaltic frequency (p = 0.0184) but did not stop peristalsis after 60 minutes of exposure in six trials. After chitosan, nifedipine (1 μM) stopped ureteral peristalsis within an average of 12.30 ± 4.72 minutes. Chitosan alone did not cause aperistalsis. Intraluminal methylene blue did not diffuse into the extraluminal bath after saline or chitosan pretreatment. Histological analysis of the ureter before and after pretreatment with chitosan showed no urothelial disruption. CONCLUSIONS By pretreating the intraluminal surface of the ureter with chitosan, nifedipine blocks ureteral peristalsis at low concentrations. Chitosan changes ureteral urothelial permeability without barrier disruption and has no observed effect on ureteral contraction.

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.