Oskar G. Kaufmann

Current status of metal stents for managing malignant ureteric obstruction

Obstruction of the ureters caused by extrinsic compression from a primary tumour or retroperitoneal lymph node masses is not unusual in the course of advanced pelvic malignancies. Most of the cases are of gynaecological or gastrointestinal origin, and the situation can be aggravated by peri‐ureteric fibrosis, a long‐term adverse event of previous chemotherapy or radiotherapy. Undoubtedly upper urinary tract decompression and maintenance of ureteric patency, even as a palliative measure, is important in managing these patients. Options for upper tract decompression include percutaneous nephrostomy, retrograde stenting and open urinary diversion. Plastic stents have long been used for managing malignant ureteric obstruction, but their overall success remains limited. Plastic stents often fail to be placed correctly, require regular exchange, and are faced with a high incidence of encrustation and migration. For these reasons plastic stents have been unsuccessful for long‐term maintenance of ureteric patency. To overcome these limitations metal stents were introduced and recently developed in an effort to ensure better long‐term patency of the obstructed ureter, fewer hospital admissions for stent change and better overall quality of life. In the present review the clinical applications of different types of metal stents are discussed, with a specific focus on the latest advances and the future options for managing malignant ureteric obstruction.

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.

Skin treatment and tract closure for tubeless percutaneous nephrolithotomy: University of California, Irvine, technique.

BACKGROUND AND PURPOSE After percutaneous nephrolithotomy (PCNL), a nephrostomy tube has been routinely placed to ensure hemostasis, provide drainage, and maintain access to the collecting system should a second-look procedure be necessary. Recently, efforts have been expended to either reduce the size of the nephrostomy tube or eliminate it altogether. We describe the tubeless technique of closure and skin treatment after PCNL using FloSeal as a sealant for tubeless PCNL. TECHNIQUE A 7F 11.5-mm occlusion balloon catheter is passed retrograde over the through-and-through guidewire. Next, under endoscopic guidance, with a rigid or flexible nephroscope, the 30F Amplatz sheath is pulled back to the torn edge of the calix through which the nephrostomy tract enters the kidney. Under endoscopic guidance, the balloon is inflated at the torn edge. Next, the long metal laparoscopic FloSeal applicator is passed through the 30F sheath until it encounters resistance from the occlusion balloon catheter. FloSeal is injected down the sheath as the sheath is slowly withdrawn simultaneously with the FloSeal applicator until both have cleared the nephrostomy incision. The through-and-through guidewire is pulled per the urethra under fluoroscopic control until its tip is in the renal pelvis. A 7F double pigtail stent is passed retrograde over the through-and-through guidewire. A bladder catheter is placed. A running subcuticular suture of 4-0 poliglecaprone is placed, and cyanoacrylate adhesive is used to close the skin. No dressing is applied. CONCLUSION For patients who have been rendered completely stone free during uncomplicated PCNL, administration of hemostatic gelatin matrix to the nephrostomy tract may achieve immediate hemostasis and eliminate the need for placement of a nephrostomy tube. Although there have not been any clinical reports of urinary obstruction caused by the application of hemostatic sealants in the PCNL tract, we recommend using an occlusion balloon and subsequent placement of an indwelling ureteral stent to ensure maximum safety.

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.

Robotic radical anterior pelvic exenteration: the UCI experience.

Abstract Robotic technology may be a promising tool in reduction of morbidity in radical anterior pelvic exenteration for invasive bladder cancer. We report our initial experience with robotic-assisted radical anterior pelvic exenteration in females in an attempt to evaluate the techniques feasibility and outcomes. A retrospective review of our bladder cancer database was performed. Twelve women that underwent robotic-assisted radical anterior pelvic exenteration, bilateral pelvic lymphadenectomy, and urinary diversion for clinically localized urothelial carcinoma of the bladder between 2004 and 2008 were included in this retrospective study. Median age was 73.0 +/- 9.6 years and median body mass index (BMI) was 23.5 +/- 5.0 kg/m2. Ten patients underwent ileal conduit diversion, one had an orthotopic neobladder and one an Indiana pouch. Median total operating time was 6.4 +/- 1.5 hours with median console and diversion times of 4.7 +/- 0.9 and 2.5 +/- 1.5 hours respectively. Median blood loss was 275.0 +/- 165.8 ml. Median length of stay was 8.0 +/- 1.6 days. Four patients were T2N0 or less, five T3N0, one T3N1 and two patients T4N0. There was one patient with positive surgical margins. Median number of lymph nodes removed was 23.0 +/- 11.4. Median follow-up of 9.0 +/- 6.0 months was available for ten patients. One had a recurrent ureteroenteric stricture, one had colpocleisis for vault prolapse, and three had metastatic disease. Robotic-assisted laparoscopic anterior pelvic exenteration appears to be a favorable surgical option with acceptable operative, pathological, and short-term clinical outcomes. According to the UCI experience, robotic anterior exenteration appears to achieve the clinical and oncologic goals for the surgical treatment of bladder cancer.

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.

Genitourinary Exam Skills Training Curriculum for Medical Students: A Follow-up Study of Comfort and Skill Utilization

PURPOSE We developed a genitourinary skills training (GUST) curriculum for incoming third year medical students (MS3) and performed a follow-up study of comfort with and utilization of these skills. MATERIALS AND METHODS GUST consisted of a didactic lecture followed by skills sessions including standardized patient testicular examination (TE) and digital rectal examination (DRE), male and female Foley catheter (MFC and FFC) placement training, suture-knot tying, and a faculty-directed small group learning session. Precourse and postcourse, and 6 and 18 months after the course, MS3 rated comfort with each skill (Likert scale 0-5), and quantified skill usage. Results were compared with 4th year students (MS4) who had not undergone GUST. RESULTS Participants were 281 MS3 GUST students and 44 MS4. Post-GUST, mean comfort on a Likert scale (0=uncomfortable) increased for all four skills (88.2%-96.9% vs 8.3%-18.5%, P<0.0001). This was maintained at the 6-month and 18-month follow up time points (P<0.0001). At 18 months, MS3 trended toward higher comfort with TE compared with MS4 (74 vs 54%, P=0.068), while with the other skills, both groups showed equal comfort. MS4 learned exam skills from faculty and MFC and FFC from nurses on the wards. Eleven percent of MS4 were never formally taught TE or DRE. MS3 and MS4 performed TE and/or DRE on <8% of newly admitted patients. CONCLUSIONS MS3 described improved comfort with the GU skills at all time points during follow-up. This was particularly important because both MS3 and MS4 reported using their skills infrequently during their clinical training years.

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.

Vaporización fotoselectiva de la próstata (VFP) vs enucleacion de la próstata con láser holmio (HOLEP): resultados actuales y estrategias

La vaporizacion foto selectiva de la prostata (VFP), con un laser de fosfato de titanio y potasio (KTP) y la enucleacion de la prostata con laser Holmio (HoLEP) representan en la actualidad las tecnicas mas prometedoras en el tratamiento de la hiperplasia benigna de prostata (HBP) asociada con obstruccion benigna de prostata (OBP). Las caracteristicas especificas del laser y las interacciones optimas entre el laser y el tejido prostatico resultan en una uniforme y eficiente ablacion de la prostata con la consiguiente formacion de una celda prostatica claramente desobstruida. El KTP y el HoLEP pueden ser considerados procedimientos ambulatorios, ya que solo requiren unas pocas horas de cateterizacion y estan asociados con minimo discomfort postoperatorio, mientras que al mismo tiempo ofrecen resultados al menos equivalentes a los estandares de referencia de la reseccion transuteral de prostata y la prostatectomia abierta. No hay duda de que se necesitan grandes estudios con seguimiento mas largo para definir con mayor precision la duracion de los resultados del KTP y el HoLEP en el manejo de la HBP. Esta revision abordara cuestiones de actualidad acerca de como se llevan a cabo ambas tecnicas, sus resultados y limitaciones, asi como su papel en el manejo futuro de la HBP.

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.