Percutaneous stone surgery using a tubeless technique with fibrin sealant: report of our first 107 cases

Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Small case series support the safety and efficacy of tubeless PCNL with fibrin sealant. However, there is a paucity of data from larger case series supporting this approach. To our knowledge, this is among the largest tubeless PCNL series. We found the use of fibrin sealant for tubeless PCNL was associated with excellent stone-free rates (approaching 90%), short hospitalisation, and low complication rates. Tubeless PCNL with nephrostomy tract fibrin sealant appears to be viable option for appropriately select patients.

OBJECTIVE

• To report on our first 107 cases of tubeless percutaneous nephrolithotomy (PCNL) using fibrin sealant as a haemostatic agent within the access tract. PCNL is the preferred treatment for patients with large renal stones, and the tubeless technique with the use of fibrin sealant has recently gained popularity.

PATIENTS AND METHODS

• We performed a retrospective review of single-access, PCNL cases performed without a nephrostomy tube from January 2002 to July 2008. • Nephrostomy tracts were sealed at the conclusion of each procedure with fibrin-containing haemostatic agents. • We evaluated demographic variables, tracked complications, and compared pre- and postoperative haemoglobin, haematocrit and creatinine levels. • On postoperative day 1 computed tomography was used to determine stone-free rates. • Student's t-test calculations were used to determine statistical significance at P ≤ 0.05.

RESULTS

• In all, 59 men and 48 women with a mean age of 43 years were included in the analysis of 107 cases. The mean stone size was 2.9 cm(2) and the average hospital stay was 1.07 days. • Pre- and postoperative changes in serum haemoglobin and serum creatinine were not statistically different. Postoperative haematocrit declined by a mean of 4.5% (P ≤ 0.05), but no patients required a transfusion. • Stone-free rates were 72% overall, and 90% when excluding patients with residual fragments of <4 mm. • Complications included seven asymptomatic subcapsular haematomas, one pseudoaneurysm requiring selective embolization, one urine leak, and five return visits to the emergency room for pain.

CONCLUSIONS

• The use of fibrin sealant in this large tubeless PCNL series was associated with favourable stone-free rates, short hospital stays, and low complication rates with no significant bleeding. • Tubeless PCNL with nephrostomy tract fibrin sealant appears to be a viable option for appropriately selected patients, but future randomised trials are warranted.

Retroperitoneal robotic-assisted laparoscopic reimplantation of a ureter into an ileal conduit

A novel technique for managing ureteroenteric strictures is robotic-assisted retroperitoneal laparoscopic reimplantation. A 63-year-old morbidly obese male underwent a left nephroureterectomy and cystoprostatectomy after neoadjuvant chemotherapy for transitional cell carcinoma of both the bladder and left kidney. His single right ureter was anastomosed to the ileal conduit. Postoperatively, he developed acute renal failure and hydronephrosis. An antegrade pyelogram demonstrated a distal stricture that failed two attempts at endoscopic management. In an effort to avoid the morbidity of an open repair, we present a minimally invasive option that replicates the steps of an open reimplantation.

Practice patterns of primary care providers and urologists for use of medical expulsion therapy

PURPOSE

Alpha-blockers and calcium channel blockers have shown promise for medical expulsion therapy (MET) of distal ureteral calculi < 1 cm in size. Although MET has been discussed in urology for some time, little has been written about MET in the emergency medicine and primary care literature. We sought to evaluate current practice patterns of MET among urologists, emergency medicine physicians, other primary care providers, and frontline military care providers.

METHODS

Web-based, self-developed survey to assess the current practice patterns of providers for the initial management of uncomplicated ureteral calculi, and specifically, their frequency of using MET. Cross-tabulation strategies utilizing compiled survey results were used to assess survey outcomes and determine prevalence values for understanding, familiarity, and therapeutic interventions for nephrolithiasis.

RESULTS

Of 293 medical professionals, 114 (39%) were urologists, 55 (48%) of which were fellowship trained in endourology. Fifty-six (19%) were emergency medicine physicians, 22 (8%) were family practitioners, and 19 (7%) were internists and other primary care physicians. Other physician subspecialists and medical paraprofessionals comprised the remaining 34%. Overall 27% of respondents were unfamiliar with MET for expulsion of uncomplicated ureteral stones, including 13% of staff physicians, 21% of emergency medicine doctors, 56% of family practitioners, 40% of internists, and 43% of other primary care providers. The overall prevalence of use of MET was 45%. All urologists were familiar with MET, but 31% rarely, never, or only sometimes used this therapy. Specifically, urologists, emergency physicians, family practitioners, internists, and other providers, usually or always used MET 69%, 55%, 16%, 16%, and 27%, of the time, respectively. In academic institutions, 71.6% use MET usually or almost always compared to 36% in military healthcare settings and 47% in other practice settings. Tamsulosin is the most widely used medication for MET, accounting for 57% of MET use. Factors identified that inhibit more widespread use of MET include, physician unfamiliarity with MET (72%), the belief that MET is not effective (10%), patient unwillingness to undergo MET (5%), and medications not covered by insurance plans (4%).

CONCLUSION

While MET has been established as a reasonable adjunct for management of uncomplicated ureteral stones, it may be underutilized due to physician unfamiliarity with this type of treatment and perceived ineffectiveness. This therapy may be of particular benefit to forward deployed forces. Education programs and practice-specific guidelines to target this audience may help to improve the dispersion of MET into the medical community.

The use of adjunctive hemostatic agents for tubeless percutaneous nephrolithotomy

Tubeless percutaneous nephrolithotomy (PCNL) is a viable option for selected patients, particularly those with solitary calculi, multiple stones located in a single location, or those that can be accessed using one access tract. Benefits over the standard PCNL include reduced hospital stay, decreased pain, and decreased urine leak from the access site that would typically occur from around the nephrostomy tube. Hemostatic agents in the form of fibrin "glue" or gelatin matrix substances have been demonstrated to be safe and effective to augment the tubeless procedure. The most appropriate sealant agent available is yet to be determined. We present a review of the contemporary literature on the use of hemostatic agents for tubeless PCNL.

Myeloid (granulocytic) sarcoma of epididymis as rare manifestation of recurrent acute myelogenous leukemia

Myeloid sarcoma involving the genitourinary system is a rare complication associated with acute myelogenous leukemia or other myeloproliferative disorders. The diagnosis is made by pathologic findings of diffuse infiltration of intermediate-size neoplastic cells and fibrosis of the affected organ. Immunohistochemically, the cells stain positive for myeloperoxidase, CD45, and CD117 but negative for CD34. Treatment involves local surgical extirpation, radiotherapy, and chemotherapy. We report the second known case of myeloid sarcoma involving the epididymis in a patient with a history of acute myelogenous leukemia.

Testis cancer: a 20-year epidemiological review of the experience at a regional military medical facility

PURPOSE

Testis cancer is the most common solid malignancy in the young adult population and the incidence in this population is increasing. We present a 20-year epidemiological review of testis cancers treated at our institution.

MATERIALS AND METHODS

The records of testis cancer cases diagnosed between January 1988 and June 2007 were reviewed. Patient demographics, cancer histology and stage, adjuvant therapy, temporal trends and survival data are presented. Our experience was compared to trends published in the SEER (Surveillance, Epidemiology and End Results) database and the National Cancer Database.

RESULTS

A total of 338 testis cancers (330 germ cell tumors) were diagnosed during the study period. Median patient age at diagnosis was 26.6 years vs 34 in the SEER database. We observed a temporal increase in stage I tumors (57% to 75%) and a decrease in the proportion of seminomas (52% to 43%) during the study period. In terms of adjuvant therapy for stage I seminoma the use of radiotherapy decreased (91% to 75%), while the use of chemotherapy increased (1.5% to 7.5%). For stage I nonseminomatous germ cell tumors the use of adjuvant chemotherapy increased (12% to 20%), while the use of staging retroperitoneal lymph node dissection decreased (88% to 63%). Five-year cancer specific survival was 97.7%.

CONCLUSIONS

We are seeing an increase in localized disease at diagnosis, an increase in surveillance for stage I disease and 5-year survival in excess of 95%, similar to data in SEER and the National Cancer Database. However, unlike in SEER and the National Cancer Database, our patients are younger, we are seeing less seminoma and we are performing significantly more staging retroperitoneal lymph node dissection.

Comparison of a novel radially dilating balloon ureteral access sheath to a conventional sheath in the porcine model

PURPOSE

Traditional ureteral access sheaths rely on tapered dilators and the Dotter principle of axial force to gain access into the ureter. We compared the performance of a novel balloon expandable ureteral access sheath using radial dilatation with that of a conventional ureteral access sheath.

MATERIALS AND METHODS

Ten farm pigs underwent randomized placement of the novel sheath in 1 ureter and a conventional ureteral access sheath in the contralateral ureter followed by videotaped ureteroscopy. Acute study end points included maximum and mean force of sheath insertion and removal, saline flow rate and subjective urothelial damage following sheath insertion/inflation. Additionally, blinded reviewers rated urothelial damage on digitally recorded video following sheath removal. Chronic data included gross and histological ureteral analysis at 30 days.

RESULTS

The novel ureteral access sheath inserted with less maximum force (0.36 vs 1.48 pounds, p <0.001) and less average force (0.11 vs 0.49 pounds, p = 0.001). The flow rate during 5 minutes was higher in the new sheath (90.0 vs 80.6 cc per minute, p <0.05). Withdrawal forces were not statistically different between the sheaths. The novel sheath also had a lower subjective trauma scale rating (4.2 vs 6.1, p <0.05). Eight blinded reviewers determined that the novel ureteral access sheath resulted in less total urothelial tear length (1.3 vs 2.7 cm, p = 0.03) and less visible ureteral damage in all animals except 1 (p = 0.04).

CONCLUSIONS

The novel balloon expandable ureteral access sheath had easier insertion and a better flow rate, and caused less urothelial trauma in this porcine model. This ureteral access sheath offers a promising new option for ureteral access. A randomized clinical trial is in progress to assess the benefits of this new ureteral access sheath.

Practice patterns of ureteral stenting after routine ureteroscopic stone surgery: a survey of practicing urologists

BACKGROUND

Controversy exists regarding the need for ureteral stent insertion after routine ureteroscopic stone surgery. We designed a questionnaire to assess and better understand the practice patterns of urologists for stent applications.

MATERIALS AND METHODS

A 26-question survey was distributed to 570 community and academic urologists. The answers were anonymously tabulated to determine the practice patterns for stent placement.

RESULTS

Of the 173 respondents, 97.7% performed ureteroscopic surgery, with the majority (77%) performing 1 to 10 procedures per month. Sixty-eight percent of urologists considered more than 70% of their ureteroscopic procedures "routine." Only 21% of urologists dilated the ureteral orifice more than 90% of the time. Those who dilated the ureteral orifice used a balloon (43%), ureteral access sheath (13.5%), or both (21%). The use of an access sheath did not change stenting practices for 75% of urologists. Patterns vary with regard to length of indwelling time, with 85% of urologists maintaining the stent for fewer than 7 days. Most urologists use either cystoscopy (42%) or pull-suture in clinic (37%) to remove stents. Patient tolerance is the most significant problem with stents reported by 97.6% of urologists. The respondents were divided into three experience-based groups: group 1, <2 years of experience; group 2, 2 to 10 years; and group 3, >10 years. Using Fisher's exact test, there were no statistically significant differences between the groups.

CONCLUSION

A wide variability exists among urologists in the practice patterns of stent insertion after routine ureteroscopic surgery. Most consider their procedures routine and are more likely to place stents after ureteral dilation despite growing evidence to the contrary. Knowledge of the varied practices may aid less experienced urologists in their decision to insert a stent after ureteroscopy.

Effect of obesity on prostate-specific antigen recurrence after radiation therapy for localized prostate cancer as measured by the 2006 Radiation Therapy Oncology Group-American Society for Therapeutic Radiation and Oncology (RTOG-ASTRO) Phoenix consensus definition

BACKGROUND

Given the limited data regarding the impact of obesity on treatment outcomes after external beam radiation therapy (EBRT) for the definitive treatment of prostate cancer, the authors sought to evaluate the effect of obesity as measured by body mass index (BMI) on biochemical disease recurrence (BCR) using the most current 2006 Radiation Therapy Oncology Group-American Society for Therapeutic Radiation and Oncology (RTOG-ASTRO) Phoenix consensus definition (prostate-specific antigen [PSA] nadir + 2 ng/mL).

METHODS

A retrospective cohort study identified men who underwent primary EBRT for localized prostate cancer between 1989 and 2003 using the Center for Prostate Disease Research (CPDR) Multi-center National Database. BMI was calculated (in kg/m(2)) and the data were analyzed. Univariate and multivariate Cox proportional hazards regression analyses were used to determine whether BMI significantly predicted BCR.

RESULTS

Of the 1868 eligible patients, 399 (21%) were obese. The median age of the patients and pretreatment PSA level were 70.2 years and 8.2 ng/mL, respectively. Of 1320 patients for whom data were available with which to calculate PSA recurrence (PSA nadir + 2 ng/mL), a total of 554 men (42.0%) experienced BCR. On univariate analysis, BMI was found to be an independent predictor of PSA recurrence (P = .02), as was race, pretreatment PSA level, EBRT dose, clinical T classification, Gleason score, PSA nadir, and the use of androgen-deprivation therapy (ADT). On multivariate analysis, BMI remained a significant predictor of BCR (P = .008).

CONCLUSIONS

To the authors' knowledge, this is the first study to report the association between obesity and BCR after EBRT for localized prostate cancer as measured by the updated 2006 RTOG-ASTRO definition. A higher BMI is associated with greater odds of BCR after undergoing definitive EBRT.

Retroperitoneoscopic radical nephrectomy for renal-cell carcinoma during twin pregnancy

Renal-cell carcinoma (RCC) is rarely reported during pregnancy. Both the open and the laparoscopic approach to nephrectomy have been used effectively and safely in pregnant patients with RCC. We report a unique case of a 52-year-old woman found to have RCC during twin gestation who was treated with retroperitoneoscopic radical nephrectomy, one of the first such cases managed by this approach.

Effect of Freeze Time during Renal Cryoablation: A Swine Model

BACKGROUND AND PURPOSE

Cryotherapy provides a minimally invasive treatment for small renal tumors via an open, percutaneous, or laparoscopic approach. We sought to determine the most appropriate duration of freezing and the number of probes necessary to produce cell death without concomitant morbidity.

MATERIALS AND METHODS

Nine domestic female pigs were divided into three groups of three animals each. Each group underwent a single freeze cycle with a commercially available cryotherapy device with 3.4-mm probes: group 1 for 5 minutes, group 2 for 10 minutes, and group 3 for 15 minutes. The right kidney was treated with a single probe, the left with a double probe. Animals were permitted to survive for an average of 4.8 days (range 4-7 days), after which the kidneys were harvested. A single pathologist examined the kidneys for gross and histologic changes. Evidence of complications (fistula, bleeding, bowel injury) was documented at the time of necropsy.

RESULTS

For group 1, the temperature obtained with a single probe 5, 10, 15, and 20 mm from the probe was -57 degrees C, 3 degrees C, 25 degrees C, and 33 degrees C, respectively; for group 2 -85 degrees C, -37 degrees C, -2 degrees C, and 25 degrees C; and for group 3 -10 degrees C, -45 degrees C, -20 degrees C, and 6 degrees C. For group 1, the temperature obtained with a double probe at 5, 10, 15, and 20 mm from each probe was -65 degrees C, 0 degrees C, 20 degrees C, and 30 degrees C, respectively; for group 2 -72 degrees C, -25 degrees C, 5 degrees C, 25 degrees C; and for Group 3 -82 degrees C, -30 degrees C, -12 degrees C, 13 degrees C. Complete necrosis was seen 5 mm from the cryoprobe within each group, but only in groups 2 and 3 did necrosis extend 10 mm or beyond the probes when utilizing either single or double probes. The maximum diameter of consistent necrosis was 35 to 40 mm in the animals in group 3 treated with a double probe. Bleeding and renal fracture were the two most common complications.

CONCLUSIONS

A 5-minute freeze appears to be inadequate to cause tissue necrosis and is associated with excessive bleeding at the time of the procedure, whereas the 15-minute freeze produces consistent necrosis but is associated with renal fracture. In this animal model, the 10-minute freeze with the single or double probe configuration appears optimal to produce necrosis without complications.

Metabolic abnormalities associated with calyceal diverticular stones

OBJECTIVE

To review the metabolic analyses of patients with calyceal diverticular stones who had surgical treatment of their calculi and to examine the effect of selective medical therapy on stone recurrence, as recent reports suggest that metabolic abnormalities contribute to stone development.

PATIENTS AND METHODS

In all, 37 patients who had endoscopic treatment of symptomatic calyceal diverticular calculi were retrospectively reviewed. Stone composition and initial 24-h urine collections (24-h urinary volumes, pH, calcium, sodium, uric acid, oxalate, citrate, and the number of abnormalities/patient per collection) were compared with 20 randomly selected stone-forming patients (controls) with no known anatomical abnormalities. Stone formation rates before and after the start of medical therapy were calculated in the patients available for follow-up.

RESULTS

Twelve of the diverticulum patients (five men and seven women) had complete 24-h urine collections, all of whom had at least one metabolic abnormality. Seven patients had hypercalciuria, four had hyperuricosuria and three had mild hyperoxaluria. The most common abnormality was a low urine volume; 11 of the 12 patients had urine volumes of <2000 mL/day (range 350-1950). Ten patients had hypocitraturia in at least one of the two 24-h urine samples; seven had low urinary citrate levels (172-553 mg/day) on both samples. The findings were similar in the control group. The diverticulum patients had 3.1 abnormalities/patient, and the controls had 2.9 abnormalities/patient (P > 0.05). No patients had gouty diathesis and none developed cystine stones. Stone analyses were similar in the two groups; both developed either calcium oxalate or mixed calcium oxalate/calcium phosphate stones. Six patients were followed for a mean of 23.1 months while on selective medical therapy; only one passed any additional stones, thought to be existing calculi, for a remission rate of five of six (83%).

CONCLUSIONS

All patients with symptomatic calyceal diverticular stones who had comprehensive metabolic evaluation had metabolic abnormalities. There were similar abnormalities in the control random stone-formers. The abnormalities were corrected with selective medical therapy, as shown by the high remission rate. We recommend that, for patients with symptomatic calyceal diverticular calculi, a metabolic evaluation should be considered to determine stone forming risk factors.

Management of nephropleural fistula after supracostal percutaneous nephrolithotomy

OBJECTIVES

Access to complex urinary tract pathology may require supracostal access placing patients at risk for intrathoracic complications. Our objective was to retrospectively review our experience with percutaneous renal surgery with a particular emphasis on identifying the incidence of nephropleural fistula and management of this unusual complication.

METHODS

The records of 375 consecutive patients who underwent percutaneous renal surgery between 1993 and 2001 were reviewed. Supracostal access was placed to address the intrarenal pathologic findings most directly in 120 (26.0%) of the 462 tracts, with 87 (18.8%) above the 12th rib, 32 (6.9%) above the 11th rib, and 1 (0.2%) above the 10th rib.

RESULTS

Of 375 patients, 4 (1%) developed a nephropleural fistula. Of the 87 with supracostal-12th rib access, 2 (2.3%) developed a nephropleural fistula, and 2 (6.3%) of the 32 with supracostal-11th rib access developed the same complication. The overall incidence of nephropleural fistulas in our patient population per access tract placed was 0.87% (4 of 462 percutaneous tracts), which increased to 3.3% (4 of 120) when considering only supracostal access. All patients were treated conservatively, although 1 patient required thoracoscopy with decortication for persistent pleural effusion. No further sequelae developed in any of the other 3 patients, and all fistulas had resolved at 3 months of follow-up.

CONCLUSIONS

As aggressive percutaneous renal surgery with supracostal access to the collecting system becomes more common, the incidence of intrathoracic complications, including nephropleural fistula, may increase. Early recognition and management of a pleural injury is critical to avoid life-threatening situations. Low-morbidity measures are typically successful; however, more aggressive treatment may be required on occasion.

PlasmaKinetic Bipolar Vessel Sealing: Burst Pressures and Thermal Spread in an Animal Model

BACKGROUND AND PURPOSE

Laparoscopic bipolar instruments are commonly employed to cauterize and divide tissue. A next-generation bipolar device has been developed that employs vapor pulse coagulation energy. We assessed the vessel-sealing capability of this device and quantified thermal spread during application.

MATERIALS AND METHODS

Bilateral laparoscopic nephrectomy was performed on six common swine >25 kg. Five-millimeter clips and surgical staplers (US Surgical, Norwalk, CT) were utilized to perform nephrectomy on one side, while the Gyrus PlasmaKinetic bipolar device (Minneapolis, MN) was employed for the contralateral nephrectomy. Vessel-sealing capabilities were assessed via burst-pressure studies. The extent of thermal spread was measured after tissue fixation and hematoxylin and eosin staining.

RESULTS

Surgical clips/vascular staplers adequately controlled/sealed renal hilar vessels with burst pressures nearing 300 mm Hg. The Gyrus bipolar device reliably sealed and divided renal arteries <or=5 mm with burst pressures averaging 291 mm Hg. Renal arteries above this size were not consistently sealed, but, with the exception of one technical error, renal veins of all sizes (3-12 mm) were reliably controlled (average burst pressure 288 mm Hg). Histologic evidence of thermal spread extended an average of 3.6 mm from the cut edges of arteries and 3.4 mm from the edges of veins.

CONCLUSIONS

The Gyrus PlasmaKinetic bipolar device is capable of reliably sealing/ dividing arteries as large as 6 mm, although we recommend restricting its use to vessels no larger than 5 mm in diameter to allow a safety margin. In addition, porcine renal veins of all sizes are adequately controlled. These sealed vessels are able to withstand pressures approaching 300 mm Hg. Thermal spread affects only the area surrounding the divided vessel. Further clinical studies are warranted.

Hand-Assisted Laparoscopic Nephrectomy: The Transfer of Experience to a New Academic Center

BACKGROUND AND PURPOSE

Hand-assisted laparoscopic nephrectomy (HALN) has become widely used for the management of localized renal masses and for simple nephrectomy [corrected] Centers of excellence have slowly disseminated this surgical approach throughout academic institutions and private practices. The transfer of this technique to inexperienced surgeons and centers has not been well studied. We examined our outcomes for HALN with an experienced surgeon (DMA) [corrected] at a new academic center. We also examined the effectiveness of the transfer of these techniques as trainees go out into practice [corrected]

PATIENTS AND METHODS

A total of 85 hand-assisted laparoscopy procedures were performed between September 2001 and August 2003 of which 61 were HALN. Four fellows and eight chief residents, under the guidance of one attending surgeon (DMA), performed all HALN procedures. Parameters measured included patient age, ASA score, body mass index, operative time, estimated blood loss, number of trocars used, time to oral intake, analgesics required, length of stay, complications, and tumor size. The average patient age was 57.4 years (range 26-87 years) and the mean ASA score 2.5 (1-4). The mean BMI was 28.3 (range 20-46) [corrected] There was a slight predominance of right-sided lesions. In addition to evaluating our early results with HALN, a questionnaire was sent to all graduates of our program starting 2 years prior to the arrival of DMA to assess the application of laparoscopy to their practices [corrected]

RESULTS

All cases were completed without open conversion. The total operative time averaged 184 [corrected] minutes (range 67-257 [corrected] minutes), with 80% of patients requiring two trocars. The average blood loss was 136 [corrected] ml (range 25-700 mL), but only one patient required transfusion postoperatively [corrected] The mean time to oral intake was 17.1 hours (range 1.5-240 hours), the average length of stay was 4.3 days (range 1-28 days), and total narcotic requirements averaged 111 mg of morphine sulfate equivalents (range 6.7-519 mg). Sixty-six percent of the procedures were performed for malignancy. The average tumor size in these cases was 3.9 cm (range 1-12 cm). There was one death, in an 80-year-old patient who had a bowel injury necessitating re-exploration and bowel resection. This patient had a postoperative myocardial infarction and died. Two patients developed postoperative hernias at their hand-port site. Other significant [corrected] complications included diaphragmatic [corrected] injury (repaired laparoscopically), one [corrected] pulmonary embolus, two cases of pancreatitis, and one case of pneumonia. Three patients experienced postoperative ileus. Of the 20 graduates of this program since 2000, 4 were laparoscopic/endourology fellows, and 2 of the residents pursued fellowship training after graduating. Graduates of the year 2000 and 2001 represent surgeons who graduated prior to the arrival of DMA. Of those resident graduates who did not pursue fellowship, two of the seven surgeons who graduated prior to the arrival of DMA are performing laparoscopy. Both of these surgeons pursued formal postgraduate laparoscopic training. Six of the seven non-fellowship-trained residents who graduated since DMA's arrival are performing laparoscopy; the other is early in practice and intends to do so. None of these surgeons has pursued postgraduate training prior to performing laparoscopy in their practices [corrected]

CONCLUSIONS

The HALN techniques can be transferred quickly and efficiently between [corrected]one center and [corrected] another under the guidance of an experienced surgeon. Operative times are acceptable, with complication rates comparable to [corrected] previously reported series. Our data show that exposure during residency markedly increases the likelihood that surgeons will carry the techniques into their practices [corrected]

IN VITRO COMPARISON OF FRAGMENTATION EFFICIENCY OF FLEXIBLE PNEUMATIC LITHOTRIPSY USING 2 FLEXIBLE URETEROSCOPES

PURPOSE

Pneumatic lithotripsy has been shown to be an effective and safe intracorporeal lithotripsy modality for renal and ureteral calculi, capable of fragmenting stones of all compositions. We determined the in vitro stone fragmentation abilities of the 0.5 mm flexible pneumatic lithotripsy probe when inserted through the working channel of 2, 7.5Fr flexible ureteroscope designs (straight working channel and offset working channel at approximately 30 degrees from the long axis of the endoscope). The velocity and displacement of the pneumatic probe tip were also evaluated with the probe inserted through each endoscope.

MATERIALS AND METHODS

The 0.5 mm (1.5Fr) stainless steel probe was tested at 5 deflection angles, namely 0, 12, 24, 33 and 48 degrees, at a pneumatic pressure of 2.5 bar when inserted through the offset and straight working channel ureteroscopes. A noncontact optical laser system was used to measure or calculate the displacement and velocity of the 0.5 mm probe tip at each angle of deflection with the 2 ureteroscopes. Fragmentation at all deflection angles was assessed using plaster of Paris stone phantoms with the pneumatic device on continuous mode at 2.5 bar pressure for 30 seconds. Stones were weighed after each fragmentation cycle and the percent weight lost was determined. Comparisons were made between the 2 ureteroscopes at each angle.

RESULTS

Probe tip displacement was significantly better through the straight channel ureteroscope with 30% improvement at all angles tested compared to the offset channel. Moreover, a substantial decrement in tip displacement was noted as the angle of deflection increased regardless of the endoscope used. Conversely tip velocity was relatively unchanged throughout the study and it was equivalent from straight to offset channel measurements. Phantom stone fragmentation correlated inversely with the severity of the deflection angle. An approximately 80% loss of fragmentation ability was noted as the angle increased from 0 to 48 degrees. Although the pneumatic device performed better through the straight channel scope, a similar percent loss in fragmentation from 0 to 48 degrees was seen when using either endoscope.

CONCLUSIONS

The flexible pneumatic 0.5 mm lithotripsy probe appears to be best used through a straight channel flexible ureteroscope, out performing use through the offset channel scope at all angles of deflection. Tip displacement and fragmentation ability were inversely related to the degree of active deflection as the angle increased from 0 to 48 degrees. Use of the flexible pneumatic probe to aid in managing renal or proximal ureteral calculi may be limited until an improved probe can be developed, allowing complete and unencumbered fragmentation throughout all angles of deflection.

FIBRIN SEALANT ENABLES TUBELESS PERCUTANEOUS STONE SURGERY

PURPOSE

Fibrin sealant has been demonstrated to be safe and effective as a hemostatic agent and urinary tract sealant. We assessed the ability of fibrin sealant to facilitate tubeless management after uncomplicated percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

Eight consecutive patients underwent single access tubeless PCNL for renal calculi in a total of 9 renal units in a 2-month period. An additional patient with distal ureteral obstruction underwent antegrade ureteroscopy for an 8 x 8 mm distal ureteral stone. Average patient age was 47 years and mean stone size was 3.37 cm (range 0.64 to 9.90). Following complete stone clearance a Double-J (Medical Engineering Corp., New York, New York) ureteral stent was placed antegrade and 2 cc HEMASEEL APR (Haemacure Corp., Sarasota, Florida) fibrin sealant was injected under nephroscopic or fluoroscopic visualization into the parenchymal defect just within the renal capsule. Preoperative and postoperative hematocrit (HCT) was determined. Computerized tomography was performed on postoperative day 1 or 2 to evaluate retained stone fragments, perinephric fluid and urinary extravasation.

RESULTS

In the 10 renal units treated via this tubeless technique no intraoperative or postoperative complications were noted. Average hospital stay was 1.1 days. All patients were discharged home on postoperative day 1 except 1 undergoing asynchronous bilateral PCNL on consecutive days. The mean intraoperative change in HCT was 2.8%. There was no significant change in HCT on postoperative day 1. No patient required transfusion. Seven renal units and 1 ureteral unit had no residual stone fragments for a complete stone-free rate of 80%. No gross leakage was observed on dressings and postoperative computerized tomography failed to demonstrate urinary extravasation.

CONCLUSIONS

Tubeless PCNL using fibrin sealant at the renal parenchymal defect appears to be safe and feasible. Further experience is necessary to determine the role of fibrin sealant in percutaneous renal surgery.

Ureteral access sheath provides protection against elevated renal pressures during routine flexible ureteroscopic stone manipulation

BACKGROUND AND PURPOSE

New-generation flexible ureteroscopes allow the management of proximal ureteral and intrarenal pathology with high success rates, including complete removal of ureteral and renal calculi. One problem is that the irrigation pressures generated within the collecting system can be significantly elevated, as evidenced by pyelovenous and pyelolymphatic backflow seen during retrograde pyelography. We sought to determine if the ureteral access sheath (UAS) can offer protection from high intrarenal pressures attained during routine ureteroscopic stone surgery.

PATIENTS AND METHODS

Five patients (average age 72.6 years) evaluated in the emergency department for obstructing calculi underwent percutaneous nephrostomy (PCN) tube placement to decompress their collecting systems. The indications for PCN tube placement were obstructive renal failure (N=1), urosepsis (N=2), and obstruction with uncontrolled pain and elevated white blood cell counts (N=2). Flexible ureteroscopy was subsequently performed with and without the aid of the UAS while pressures were measured via the nephrostomy tube connected to a pressure transducer. Pressures were recorded at baseline and in the distal, mid, and proximal ureter and renal pelvis, first without the UAS, and then with the UAS in place.

RESULTS

The average baseline pressure within the collecting system was 13.6 mm Hg. The mean intrarenal pressure with the ureteroscope in the distal ureter without the UAS was 60 mm Hg and with the UAS was 15 mm Hg. With the ureteroscope in the midureter, the pressures were 65.6 and 17.5 mm Hg, respectively; with the ureteroscope in the proximal ureter 79.2 and 24 mm Hg, and with the ureteroscope in the renal pelvis 94.4 and 40.6 mm Hg, respectively. All differences at each location were statistically significant (P<0.008). Compared with baseline, all pressures measured without the UAS were significantly greater, but only pressures recorded in the proximal ureter and renal pelvis after UAS insertion were significantly higher (P<0.03).

CONCLUSIONS

The irrigation pressures transmitted to the renal pelvis and subsequently to the parenchyma are significantly greater during routine URS without the use of the UAS. The access sheath is potentially protective against pyelovenous and pyelolymphatic backflow, with clinical implications for the ureteroscopic management of upper-tract transitional cell carcinoma, struvite stones, or calculi associated with urinary tract infection.

Internet based multi-institutional clinical research: a convenient and secure option

PURPOSE

As randomized, prospective trials have become an integral part of clinical research, multi-institutional, collaborative research has become a necessity. However, it may be cumbersome for participants at remote facilities to participate because the submission and compilation of data and results are at times lengthy processes. Internet based clinical studies have been found to be a rapid, easily accessible, safe and secure method of performing multi-institutional trials.

MATERIALS AND METHODS

The Internet was used at geographically distant medical centers to enroll patients into a multi-institutional, prospective, randomized trial for the management of lower pole renal calculi. The Clinical Research Web-based Information Center secure computer web based program (Simplified Clinical Data Systems, Amherst, New Hampshire) was established to input preliminary demographic and clinical data, randomize patients, and collect treatment and followup information without paper chart documentation. The primary investigators in the study were sent a questionnaire to determine the ease of use of this Internet based program. The results were tabulated.

RESULTS

A total of 112 patients from 21 participating institutions were randomized into the secure web site for inclusion into a lower pole renal stone clinical trial. Of the investigators 64% responded to the questionnaire. The majority of those having enrolled patients into the study reported no difficulties or only minimal difficulties in navigating the web site. Moreover, investigators from remote locations throughout North America described the improved convenience, rapid transmission of information, and ability to review and update patient data as benefits of enrolling patients using the Internet. The Internet based system also permits the prompt compilation of data at the host research site for performing interim data assessments and eventually the final analysis.

CONCLUSIONS

A web based data collection center allows for large, multi-institutional trials to be done with unprecedented accuracy and efficiency. Through centralization of data capture, and real-time study monitoring and data analysis the system removes these responsibilities from those at individual test sites, permitting investigators to concentrate instead on other aspects of the study and its progress. State-of-the-art security protects all information to ensure confidentiality. The Internet may prove to be an invaluable tool in the future of clinical research.

Hand-Assisted Laparoscopic Approach to Simple Nephrectomy

Laparoscopic nephrectomy is commonly employed today for both malignant and benign renal conditions, yet the learning curve for all but the simplest procedures remains quite steep. Hand-assisted laparoscopic nephrectomy (HALN) bridges the gap between standard laparoscopy and open surgery, allowing urologists to develop laparoscopic skills while offering the advantages of minimally invasive surgery. Simple laparoscopic nephrectomy, performed for benign disorders, can at times prove to be challenging because of inflammation around the renal hilum. Meticulous dissection during HALN utilizing the intra-abdominal hand for tactile feedback, retraction, and blunt dissection may improve one's capabilities compared with the standard laparoscopic approach.

Cost comparison of radical retropubic and radical perineal prostatectomy: single institution experience

OBJECTIVES

To perform a detailed comparison of the in-house hospital costs of patients undergoing radical perineal prostatectomy (RPP) and radical retropubic prostatectomy (RRP) performed with or without bilateral staging lymph node dissection (BPLND) for localized prostate cancer.

METHODS

A retrospective cost review was done of a cohort of 402 consecutive radical prostatectomies performed at our institution during a 21-month period. The procedure was performed as RPP in 279 (69.4%) and RRP in 123 (30.6%) patients, of whom 10.4% and 61.8%, respectively, underwent BPLND under the same anesthesia. The hospital costs were evaluated for each patient using the categories of surgical, nursing, laboratory/transfusion, and pharmacy. Surgical costs were further subdivided into operating room, anesthesia, and recovery room costs. Univariate and multivariate statistical analyses were applied to identify predictors of procedure-related costs.

RESULTS

The median hospital costs of patients undergoing RPP (7195 dollars, range 5052 dollars to 36,237 dollars) were substantially lower than those of patients undergoing RRP (9757 dollars, range 6935 dollars to 27,771 dollars; P = 0.001). The median costs for patients undergoing radical prostatectomy without BPLND were significantly lower in the RPP (7100 dollars, range 5052 dollars to 28,604 dollars) versus RRP (9169 dollars, range 6935 dollars to 16,705 dollars) patients (P = 0.001). The costs for RPP with BPLND (10,048 dollars, range 7529 dollars to 36,237 dollars) versus RRP with BPLND (9973 dollars, range 7658 dollars to 27,771 dollars) were not significantly different (P = 0.900). Patient age and nerve-preservation status did not significantly influence the procedure-related hospital costs.

CONCLUSIONS

RPP may result in lower in-house costs per patient than RRP in those patients who do not require BPLND. Total hospital costs depend largely on the factors of operating room time, length of stay, and laboratory and transfusion requirements, which may vary among institutions.

Advances in the surgical management of nephrolithiasis

The surgical management of urinary calculus disease has undergone a dramatic evolution over the past 2 decades. Twenty years ago, open surgical procedures for urinary calculi were some of the most frequently performed urologic procedures. Since then, however, stone management has been at the forefront of "minimally invasive" intervention. Specifically, the initiation and refinement of percutaneous and ureteroscopic access to the upper tracts, along with the rapid and nearly simultaneous development of both extracorporeal and intracorporeal lithotripsy techniques, has limited the role of open surgery to less than 1% of patients undergoing intervention for their stone disease. This manuscript will review the current indications for the surgical management of urinary calculi, the basic physics of the most frequently utilized vehicles for both extracorporeal and intracorporeal lithotripsy, and the respective roles of extracorporeal and intracorporeal lithotripsy with percutaneous or ureteroscopic access and open surgery. In addition, the results and complications associated with each of these forms of intervention will be reviewed. Finally, a discussion of specific clinical challenges to the urologist will be presented.

Metabolic Abnormalities Associated With Renal Calculi in Patients with Horseshoe Kidneys

BACKGROUND AND PURPOSE

Horseshoe kidneys are a complex anatomic variant of fused kidneys, with a 20% reported incidence of associated calculi. Anatomic causes such as high insertion of the ureter on the renal pelvis and obstruction of the ureteropelvic junction are thought to contribute to stone formation via impaired drainage, with urinary stasis, and an increased incidence of infection. In this multi-institutional study, we evaluated whether metabolic factors contributed to stone development in patients with horseshoe kidneys.

PATIENTS AND METHODS

A retrospective review of 37 patients with horseshoe kidneys was performed to determine if these patients had metabolic derangements that might have contributed to calculus formation. Stone compositions as well as 24-hour urine collections were examined. Specific data points of interest were total urine volume; urine pH; urine concentrations of calcium, sodium, uric acid, oxalate, and citrate; and number of abnormalities per patient per 24-hour urine collection. These data were compared with those of a group of 13 patients with stones in caliceal diverticula as well as 24 age-, race-, and sex-matched controls with stones in anatomically normal kidneys.

RESULTS

Eleven (9 men and 2 women) of the 37 patients (30%) with renal calculi in horseshoe kidneys had complete metabolic evaluations available for review. All patients were noted to have at least one abnormality, with an average of 2.68 abnormalities per 24-hour urine collection (range 1-4). One patient had primary hyperparathyroidism and underwent a parathyroidectomy. Low urine volumes were noted in eight patients on at least one of the two specimens (range 350-1640 mL/day). Hypercalciuria, hyperoxaluria, hyperuricosuria, and hypocitraturia were noted in seven, three, six, and six patients, respectively. No patients were found to have gouty diathesis or developed cystine stones. Comparative metabolic analyses of patients with renal calculi in caliceal diverticula or normal kidneys revealed a distinct profile in patients with horseshoe kidneys, with a higher incidence of hypocitraturia.

CONCLUSIONS

All patients with renal calculi in horseshoe kidneys were noted to have metabolic abnormalities predisposing to stone formation. In this initial series of 11 patients, hypovolemia, hypercalcuria and hypocitraturia were most common metabolic defects. These findings suggest that metabolic derangements play a role in stone formation in patients with a horseshoe kidney. Patients with calculi in anatomically abnormal kidneys should be considered for a metabolic evaluation to identify their stone-forming risk factors in order to initiate preventative selective medical therapy and reduce the risk of recurrent calculus formation.

Bilateral Renal Calculi: Assessment of Staged v Synchronous Percutaneous Nephrolithotomy

BACKGROUND AND PURPOSE

Percutaneous stone removal has replaced open renal surgery and has become the treatment of choice for large or complex renal calculi. However, patients with large bilateral stone burdens still present a challenge. Simultaneous bilateral percutaneous nephrolithotomy (PCNL) has been demonstrated to be a well-tolerated, safe, cost-effective, and expeditious treatment. We present what is, to our knowledge, the first large retrospective series comparing synchronous and asynchronous bilateral PCNL.

PATIENTS AND METHODS

A chart review was performed on 26 patients undergoing 57 PCNLs for bilateral renal calculi over a 7-year period. Seven patients received synchronous PCNL (same anesthesia; Group 1), and 19 patients underwent asynchronous PNL (procedures separated by 1-3 months; Group 2). Complete surgical and hospital records were available on all patients. The average stone burden for Group 1 was 8.03 cm(2) on the left and 9.18 cm(2) on the right v 10.1 cm(2) on the left and 14.23 cm(2) on the right for Group 2 (P> 0.05). Variables of interest included anesthesia time, operative time, blood loss, transfusion rates, length of hospital stay, and complication rates. Each variable was evaluated per operation and per renal unit. Follow-up imaging with stone assessment was available on 20 patients.

RESULTS

Group 1 required 1.14 access tracts per renal unit to attempt complete clearance of the targeted stones v 1.88 tracts per renal unit in Group 2 (P> 0.05). The average operative time per renal unit was significantly less in Group 1 (83 minutes) than in Group 2 (168.5 minutes) (P< 0.0001), as was blood loss (178.5 mL v 307.4 mL, respectively; P= 0.02). However, blood loss per operation was similar at 357 mL in Group 1 and 282 mL in Group 2. Comparable transfusion rates of 28.6% and 36.8%, respectively, were noted. Forty percent of the patients in Group 1 were completely stone free compared with 36% of the patients in Group 2; however, an additional 50% and 57%, respectively, had residual stone burden <4 mm (P> 0.05). Complications occurred in 2 of 7 operations (28%) in Group 1 and 8 of 42 operations (19%) in Group 2. The total length of hospital stay was nearly doubled for patients undergoing staged PCNL (P= 0.0005).

CONCLUSIONS

These results demonstrate similar stone-free rates, blood loss per operation, and transfusion rates for simultaneous and staged bilateral PCNL. The reduced total operative time, hospital stay, and total blood loss, along with the requirement for only one anesthesia, makes synchronous bilateral PCNL an attractive option for select individuals. However, in patients with larger, less easily accessible stones, excessive bleeding may be encountered more frequently on the first side, thereby delaying management of the second side to a later date. Synchronous bilateral PCNL should be considered in patients in whom the first stage of stone removal is accomplished quickly and safely.

Determining the incidence of horseshoe kidney from radiographic data at a single institution

PURPOSE

An estimated 150,000 children are born with birth defects each year. One of the most frequent genitourinary abnormalities is horseshoe kidney (HSK). The incidence of HSK in the population is estimated to be 1/400 to 1,600 births based on autopsy data from the 1940s and 1950s. We prospectively evaluated the incidence of HSK based on radiographic studies to determine the contemporary incidence of HSK.

MATERIALS AND METHODS

In a 6-month period patients undergoing abdominal computerized tomography, renal ultrasonography and excretory urography were screened for HSK. After identification medical charts were reviewed for demographics, history, study indication and findings. A literature review of 12 studies of 825 patients with HSK was compared with the current series with regard to common associated findings.

RESULTS

From 15,320 radiographs 23 patients were identified with HSK for an overall incidence of 1/666. Computerized tomography, excretory urography and ultrasound identified 16, 5 and 2 patients, respectively, while 16 were male, 7 were female, 20 were adults and 3 were children. The most common concomitant urological disorder was nephrolithiasis in 9 patients (39%), prompting operative intervention in 4. The radiographic incidence of HSK closely matched data from autopsy series and yet it differed from that in current radiographic series using ultrasound in the perinatal period.

CONCLUSIONS

Our radiographic evaluation of the HSK incidence closely matches past autopsy series. This finding suggests that the incidence of HSK remains stable despite an increasing number of birth defects. Moreover, it appears that radiographic studies can accurately estimate the incidence of congenital anatomical disorders. Our data suggest that HSK is a relatively benign condition with a low requirement for operative intervention in these incidentally identified patients.

Pain after percutaneous nephrolithotomy: impact of nephrostomy tube size

BACKGROUND AND PURPOSE

Percutaneous nephrolithotomy (PCNL) is the procedure of choice for managing large renal calculi. Investigations have recently focused on reducing the morbidity of the procedure and improving postoperative patient comfort by using smaller endoscopic instruments. We sought to evaluate the effect of a smaller percutaneous drainage catheter on postoperative pain.

PATIENTS AND METHODS

Thirty consecutive patients were randomized to receive either a 10F pigtail catheter or a 22F Councill-tip catheter for their percutaneous drainage after PCNL. The demographics were similar in the two groups, as was the rate of supracostal access (47% v 43%, respectively). Self-assessed analog pain scores were collected at 6 hours postoperatively as well as on the morning of the first and second postoperative days (POD). Total narcotic usage was tabulated using morphine equivalents. Complications, including the change from baseline hematocrit, were reviewed.

RESULTS

There was no significant difference in the change in hematocrit (6.8 v 6.2 percentage points, respectively). Those patients with the smaller nephrostomy tube noted significantly lower pain scores at 6 hours (3.75 v 5.3; P=0.03). Although the pain scores were lower on POD 1 and 2 for the 10F catheter group, the difference was not statistically different (1.9 v 2.9 and 1.25 v 1.9, respectively; both P>0.05). The patients having the 10F catheter required fewer narcotics: 78 mg v 91 mg, although the difference was not statistically significant.

CONCLUSION

The use of a small drainage catheter after PCNL is associated with lower pain scores in the immediate postoperative period, yet no statistically significant benefit to the patient with regard to comfort is demonstrated beyond 6 hours. In addition, there is a trend toward reduced narcotic requirements. Finally, there is no apparent increase in patient morbidity from the use of the smaller nephrostomy tubes.

Percutaneous management of calculi within horseshoe kidneys

PURPOSE

Percutaneous treatment of patients with calculi in a horseshoe kidney can be challenging due to the altered anatomical relationship in the retroperitoneum. Therefore, we performed a multi-institutional review to assess the safety and efficacy of this minimally invasive technique.

MATERIALS AND METHODS

Of 37 patients identified with calculi in a horseshoe kidney at 3 institutions 24 (65%) underwent percutaneous nephrolithotripsy as primary treatment. Average patient age was 48.4 years and 75% of the patients were male. In 3 patients with staghorn calculi mean stone size as measured by computed digitized stone surface area was 448 mm2. Mean followup was 5.8 months. The stone-free rate, complication rate, need for secondary intervention and stone composition were evaluated.

RESULTS

Renal access was obtained through an upper pole calix in 63% of the cases, a lower calix in 25% and a middle calix in 4%. Access location was not documented in 1 patient (4%). Of the 24 patients 21 (87.5%) were rendered stone-free after primary or second look procedures. Flexible nephroscopy was used in 84% of cases. Minor complications occurred in 4 patients (16.7%), whereas 3 (12.5%) experienced major complications, including significant bleeding necessitating early cessation, nephropleural fistula and pneumothorax. No deaths occurred as a result of this treatment choice. Stone analysis was available for 21 cases (87.5%). Calcium stones predominated (87.5%), followed by uric acid (9.5%) and struvite (4.8%).

CONCLUSIONS

Percutaneous treatment of patients with renal calculi in a horseshoe kidney is technically challenging, usually requiring upper pole access and flexible nephroscopy due to the altered anatomical relationships of the fused renal units. The success rate based on stone-free results and a relatively low incidence of major complications suggest that this minimally invasive management option is an effective means of stone management in this complex patient population.

Use of a temporary ureteral drainage stent after uncomplicated ureteroscopy: results from a phase II clinical trial

PURPOSE

An indwelling ureteral stent is commonly placed for 48 hours after uncomplicated ureteroscopy to maintain drainage and prevent postoperative complications. A propriety temporary ureteral drainage stent (TUDS, Boston Scientific/Microvasive, Natick, Massachusetts) was developed to satisfy this goal with the added advantages of biodegradability and spontaneous passage. We evaluated TUDS performance in a patient population.

MATERIALS AND METHODS

A total of 88 patients at 6 centers were selected for TUDS placement. Device safety as well as effectiveness, defined as adequate intervention-free drainage for 48 hours with the maintenance of ureteral position, were the primary study end points. Secondary end points consisted of the time required to eliminate TUDS from the body, tolerability of device presence and passage, and overall patient satisfaction with the stent.

RESULTS

A single patient was excluded from primary end point analysis because of inadequate day 2 evaluation, resulting in an overall stent effectiveness rate of 78.2% (68 of 87 patients). Primary end point failure occurred in the remaining 19 patients (21.8%) with early stent extrusion in 17 and intervention required in 2 others within 48 hours of stent placement (cystoscopy and intravenous analgesia in 1, and intravenous analgesia alone in 1). There were no adverse clinical sequelae in 16 patients who experienced early extrusion with only 1 requiring intravenous pain medication. Stent fragments were retained beyond 3 months in 3 patients, of whom 2 were treated in a minimally invasive manner with shock wave lithotripsy, while 1 required ureteroscopy and shock wave lithotripsy to clear the residual fragments. Median time to stent elimination from the ureter and from the body was 8 and 15 days, respectively. Overall 71 of the 80 patients (89%) reported satisfaction with TUDS.

CONCLUSIONS

The concept of a self-degrading internal ureteral stent represents a new paradigm in ureteral drainage. TUDS combines adequate ureteral drainage and patient satisfaction after uncomplicated ureteroscopy, eliminating the need for stent removal.

Use of bipolar laparoscopic forceps to occlude and transect the retroperitoneal vasculature: a porcine model

BACKGROUND AND PURPOSE

Surgical clips are commonly employed during laparoscopic radical nephrectomy to ligate perihilar vessels reliably, yet these clips can interfere with the application of a vascular stapler to major vessels, potentially leading to catastrophic hemorrhage. We assessed the efficacy of the PlasmaKinetic trade mark (PK) bipolar cutting forceps (Gyrus Medical, Minneapolis, MN) as a single modality in coagulating and dividing the retroperitoneal vessels in a swine model.

MATERIALS AND METHODS

Three 40- to 50-kg domestic swine (six renal units) underwent celiotomy and retroperitoneal exposure. The inferior vena cava (IVC) and the renal, gonadal, and iliac vessels were isolated, and, using 5- and 10-mm forceps, coagulated and divided. The mean diameter of the renal vein was 8.7 mm, the renal artery 6.5 mm, and the IVC 14 mm.

RESULTS

Hemostasis was achieved consistently using the 5-mm and 10-mm PK Cutting Forceps on the renal artery, renal vein, and gonadal vein. The 10-mm forceps coagulated the iliac veins and IVC 83% of the time with only a single application. Larger vessels or vessels with higher inherent vascular pressure required additional applications of the device to achieve hemostasis. All animals were hemodynamically stable through division of the IVC, as measured by heart rate and pulse oximetry. No complications were noted with the device or using the cutting element.

CONCLUSIONS

The PK bipolar cutting forceps appear to be effective in controlling and dividing the renal hilar vessels and larger low-pressure vessels of the porcine retroperitoneum, with no gross damage to adjacent structures. Although further studies are necessary before use during laparoscopic nephrectomy in humans, these results are promising. Bipolar cutting forceps may prove to be a safe, cost-effective, and time-saving device with numerous applications during urologic laparoscopy.

Clinical efficacy of a combination pneumatic and ultrasonic lithotrite

PURPOSE

A new combination pneumatic/ultrasonic intracorporeal lithotriptor has been developed for percutaneous applications. It combines the stone clearing efficiency of an ultrasonic device with the fragmentation strength of a pneumatic probe into a single handpiece. We present our early clinical experience with this device in a prospective, randomized comparison a combination pneumatic/ultrasound lithotrite and standard ultrasonic lithotripsy.

MATERIALS AND METHODS

A total of 20 consecutive patients undergoing percutaneous nephrolithotomy for symptomatic calculi were randomized to receive stone fragmentation and removal using a standard ultrasonic device or a new combination pneumatic/ultrasonic unit. Stone location and burden were assessed before the operative procedure. The stone clearance rate in mm.2 per minute was calculated for the 2 devices. Complications and stone-free rates were compared in the 2 groups.

RESULTS

There were no significant differences in stone location and composition in the 2 groups of patients. Average time required for complete stone clearance was considerably less for the combination device (21.1 versus 43.7 minutes, p = 0.036). The opposite was true for the average rate of stone clearance in mm.2 per minute, in that the standard ultrasonic device could clear 16.8 versus 39.5 mm.2 per minute for the combination unit (p = 0.028). Stone-free and complications rates were slightly superior for the combination device but it was likely attributable to patient factors.

CONCLUSIONS

The combination pneumatic/ultrasonic lithotrite is capable of disintegrating and extracting stone material at a more rapid rate than standard ultrasonic devices. Moreover, stone-free and complication rates appear to be slightly superior with the combination unit. This new combination pneumatic/ultrasonic device appears to be efficacious and safe for removing large renal calculi.

In vitro analysis of stone fragmentation ability of the FREDDY laser

BACKGROUND AND PURPOSE

The Frequency-Doubled Double-Pulse Nd:Yag) (FREDDY) laser (World of Medicine, Berlin Germany) is a short-pulsed, double-frequency solid-state laser with wavelengths of 532 and 1064 nm. This low-power, low-cost laser was developed for intracorporeal lithotripsy. We designed an experimental set-up to test its fragmentation efficiency at different energy and frequency settings.

MATERIALS AND METHODS

Forty previously weighed plaster-of-Paris stone phantoms were divided into four groups in order to test fragmentation at 5 and 10 Hz for 2 and 4 minutes. A hands-off underwater laboratory set-up including a holder to keep the stone phantom in contact with the quartz laser fiber was utilized. The 280-microm laser fiber was cleaved and stripped between runs to ensure optimal energy delivery. After fragmentation was completed, all of the stone fragments remaining within the holder were allowed to desiccate for 48 hours and reweighed. Fragmentation was measured as the percentage weight loss.

RESULTS

Stone phantoms fragmented at 5 Hz for 2 minutes sustained a mean 24% loss of weight, whereas the 4-minute treatment at 5 Hz reduced stone weight by 54%. Treatment at 10 Hz for 2 minutes demonstrated results similar to those of stones treated for 4 minutes at 5 Hz, reducing stone weight by 51%. Fragmentation at 10 Hz for 4 minutes revealed a 64% loss of mass, less than expected for these power settings. Fiber deterioration observed at the higher energy settings may be the cause of the reduced stone-fragmentation efficiency.

CONCLUSIONS

Fragmentation with the FREDDY laser in the 5 Hz, 4 minutes and 10 Hz, 2 minutes protocols is comparable, suggesting that stone fragmentation correlates well with the total energy delivered to the stone. The slight drop in fragmentation efficiency at 10 Hz, 4 minutes is most likely explained by fiber damage occurring consistently at these higher energy settings. The safety profile and low investment and running costs of this laser are advantages that suggest the laser warrants further clinical trials.