Ephrem O. Olweny

Evaluation of a Vessel Sealing System, Bipolar Electrosurgery, Harmonic Scalpel, Titanium Clips, Endoscopic Gastrointestinal Anastomosis Vascular Staples and Sutures for Arterial and Venous Ligation in a Porcine Model

PURPOSE We assessed the usefulness of the LigaSure (Valleylab, Boulder, Colorado) vessel sealing system for vascular control during laparoscopic surgery and compared it with other available hemostatic modalities. MATERIALS AND METHODS A total of 31 domestic pigs were divided into 5 groups. In groups 1 and 2 the vessel sealing system was compared with titanium clips and Endo-GIA (United States Surgical, Stamford, Connecticut) staples. In group 3 the vessel sealing system was compared with standard Klepinger (Karl Storz, Culver City, California) bipolar forceps. In group 4 the harmonic scalpel and Trimax (United States Surgical) bipolar forceps were compared. In group 5 in vivo laparoscopic application of the vessel sealing system was evaluated. RESULTS The 5 mm. laparoscopic vessel sealing system sealed arteries up to 6 mm. and veins up to 12 mm. in diameter at supraphysiological bursting pressure. We evaluated 13 arteries with a diameter of 6 mm. or less at a mean bursting pressure of 662 mm. Hg (range 363 to 1,985) and 11 veins with a diameter of 12 mm. or less with a mean bursting pressure of 233 mm. Hg (range 63 to 440). Collateral tissue damage extended 1 to 3 mm. from the application site. Standard bipolar energy with Klepinger and Trimax forceps was less reliable and in some cases vessel sealing could not be accurately assessed before vessel division. Collateral tissue injury was 1 to 6 mm. The harmonic scalpel did not reliably seal vessels larger than 3 mm. but resulted in the least acute collateral tissue injury of 0 to 1 mm. CONCLUSIONS In the porcine model the LigaSure system is a viable option for laparoscopic management of arteries up to 6 mm. and veins up to 12 mm. in diameter.

FLEXIBLE URETEROSCOPES: A SINGLE CENTER EVALUATION OF THE DURABILITY AND FUNCTION OF THE NEW ENDOSCOPES SMALLER THAN 9Fr

PURPOSE Flexible ureteroscopes smaller than 9Fr are widely used in endourology. We systematically evaluated the functional durability of these instruments in the clinical setting. MATERIALS AND METHODS We performed ureteronephroscopy 92 consecutive times in 84 patients at our hospital using a flexible Storz model 11274AA,double dagger Circon-ACMI model AUR-7, section sign Wolf model 7325.172 parallel and Olympus model URF/P3 ureteroscope paragraph sign. Preoperatively and postoperatively we evaluated all flexible ureteroscopes for luminosity, irrigant flow at 100 mm. Hg, number of broken image fibers and active deflection range. During the procedure a record was kept of the duration that the endoscope remained in the urinary tract, average irrigation pressure, method of insertion, various devices used within the working channel, need for lower pole access, and surgeon overall impression of visibility and maneuverability. RESULTS The luminosity and irrigant flow of all endoscopes remained relatively unchanged during consecutive applications, while active deflection deteriorated 2% to 28%. Endoscopes were used for an average of 3 to 13 hours before they needed repair. The most fragile part of these instruments was the deflection unit. CONCLUSIONS Small diameter flexible ureteroscopes are effective for diagnosing and treating upper urinary tract pathology but improved durability is required. Currently they represent a highly effective but high maintenance means of achieving retrograde access to the ureter and kidney with a need for repair after only 6 to 15 uses.

Radiofrequency Ablation Versus Partial Nephrectomy in Patients with Solitary Clinical T1a Renal Cell Carcinoma: Comparable Oncologic Outcomes at a Minimum of 5 Years of Follow-Up

BACKGROUND Long-term comparative outcomes for radiofrequency ablation (RFA) versus partial nephrectomy (PN) for the primary treatment of clinical T1a renal cell carcinoma (RCC) have not previously been reported. OBJECTIVE Report comparative 5-yr oncologic outcomes for RFA versus PN in patients with clinical T1a RCC. DESIGN, SETTING, AND PARTICIPANTS Observational single-institution cohort study, involving consecutive patients with a solitary histologically confirmed T1a RCC treated by RFA or PN and followed for a minimum of 5 yr. Those presenting with synchronous multiple, metachronous, bilateral, and/or metastatic disease, a history of hereditary RCC syndromes, a family history of RCC, and with post-treatment follow-up <5 yr were excluded from analysis. MEASUREMENTS The Kaplan-Meier method was used to determine 5-yr overall survival (OS), cancer-specific survival (CSS), local recurrence-free survival (local RFS), overall disease-free survival (DFS), and metastasis-free survival (MFS) for RFA versus PN. Survival curves were compared using the log-rank test. A p value ≤ 0.05 was considered statistically significant. RESULTS AND LIMITATIONS A total of 37 patients in each group met the selection criteria. The RFA cohort was significantly older and had more advanced comorbidities, but other patient characteristics were similar. For RFA versus PN, median follow-up was 6.5 yr (interquartile range [IQR]: 5.8-7.1) versus 6.1 yr (IQR: 5.4-7.3) (p = 0.68), respectively. The 5-yr OS was 97.2% versus 100% (p = 0.31), CSS was 97.2% versus 100% (p = 0.31), DFS was 89.2% versus 89.2% (p = 0.78), local RFS was 91.7% versus 94.6% (p = 0.96), and MFS was 97.2% versus 91.8% (p = 0.35), respectively. Study limitations are retrospective data analysis, loss to follow-up, limited statistical power, and limited generalizability of our data. CONCLUSIONS In appropriately selected patients, RFA is an effective minimally invasive therapy for the treatment of cT1a RCC, yielding comparable long-term oncologic outcomes to nephron-sparing surgery.

Flexible ureteroscopic lithotripsy: first-line therapy for proximal ureteral and renal calculi in the morbidly obese and superobese patient.

BACKGROUND AND PURPOSE The surgical treatment of kidney and proximal ureteral stones in morbidly obese patients (>14 kg/m2) remains difficult because shockwave lithotripsy is precluded by weight limitations and percutaneous nephrolithotomy is associated with difficult access and a high (9%) rate of transfusion. We review our experience with retrograde ureteroscopic lithotripsy in morbidly obese patients with renal and proximal ureteral stones. PATIENTS AND METHODS Between December 1992 and April 2000, five women and three men with a mean age of 46.5 years (range 33-68 years) and a mean body mass index of 54 (range 45-65.2) underwent 10 independent ureteroscopic procedures for urolithiasis. The average stone size was 11.1 mm (range 5-25 mm). Lithotripsy was performed with the holmium laser in eight patients (60%) the electrohydraulic lithotripter in four (30%), and the tunable-dye laser in the remaining patient. Stone-free status was defined as no stones visible on a plain film with nephrotomograms or CT scan at 3 months. RESULTS The mean operation time was 101 minutes (range 45-160 minutes), and 60% of the procedures were done on an outpatient basis. After the initial procedure, the stone-free rate was 70%. Two patients had fragments <4 mm, and no further therapy was undertaken. There was one complication: transient renal insufficiency (serum creatinine concentration 3.7 mg/dL) secondary to aminoglycoside toxicity. No transfusions were needed. CONCLUSION In the morbidly obese patient with symptomatic stones <1.5 cm, ureteroscopic lithotripsy is safe, successful, and efficient.

Long-Term Outcomes of Renal Tumor Radio Frequency Ablation Stratified by Tumor Diameter: Size Matters

PURPOSE Renal tumor size influences the efficacy of radio frequency ablation but identification of confident size cutoffs has been limited by small numbers and short followup. We evaluated tumor size related outcomes after radio frequency ablation for patients with adequate (greater than 3 years) followup. MATERIALS AND METHODS We identified 159 tumors treated with radio frequency ablation as primary treatment. Disease-free survival was defined as the time from definitive treatment to local recurrence, detection of metastasis or the most recent imaging showing no evidence of disease. Patients were evaluated with contrast enhancing imaging preoperatively, and at 6 weeks, 6 months and at least annually thereafter. RESULTS Median tumor size was 2.4 cm (range 0.9 to 5.4) with a median followup of 54 months (range 1.5 to 120). Renal cell carcinoma was confirmed in 72% of the 150 tumors that had pre-ablation biopsy (94%). The 3 and 5-year disease-free survival was comparable at 92% and 91% overall, and was dependent on tumor size, being 96% and 95% for tumors smaller than 3.0 cm and 79% and 79%, respectively, for tumors 3 cm or larger (p=0.001). Most failures (14 of 18) were local, either incomplete ablations or local recurrences. This is an intent to treat analysis and, therefore, includes patients ultimately found to have benign tumors, although outcomes were comparable in patients with cancer. CONCLUSIONS Radio frequency ablation treatment success of the small renal mass is strongly correlated with tumor size. Radio frequency ablation provides excellent and durable outcomes, particularly in tumors smaller than 3 cm. Of tumors 3 cm or larger, approximately 20% will recur such that alternative treatment techniques should be considered. However, most treatment failures are local and are often successfully treated with another ablation session.

Patient-reported body image and cosmesis outcomes following kidney surgery: Comparison of laparoendoscopic single-site, laparoscopic, and open surgery

BACKGROUND Laparoendoscopic single-site surgery (LESS) is reported to result in superior cosmesis versus alternative surgical approaches, based solely on surgeon assessment or anecdotal evidence. OBJECTIVE Evaluate patient-reported body image and cosmesis outcomes following kidney surgery. DESIGN, SETTING, AND PARTICIPANTS We conducted a prospective and retrospective observational cohort study involving patients who underwent kidney surgery (n=114) via LESS (n=35), laparoscopic (n=52), or open (n=27) approaches. Cosmesis was evaluated using a comprehensive survey administered ≥3 mo postoperatively. MEASUREMENTS Survey components were a body image questionnaire (BIQ) consisting of body image and cosmesis subscales, a photo-series questionnaire (PSQ) assessing scar preferences after knowledge of scar outcomes for alternative surgical approaches, and query of preference for future surgical approach using a trade-off method. Body image, cosmesis, and PSQ scales ranged from 5 to 20, 3 to 24, and 1 to 10, respectively. RESULTS AND LIMITATIONS Median BIQ component scores did not significantly differ across surgical approaches. Median ratings for the LESS, laparoscopy, and open scar photographs were 8, 5, and 5, respectively (p=0.0001). Before viewing photographs, median self-scar ratings for LESS, laparoscopy, and open approaches were 9, 5, and 6.5, respectively (p=0.02); after photographs, ratings were 9, 7, and 7, respectively (p=0.008). Assuming equivalent surgical risk among the approaches, overall preference for future LESS, laparoscopy, or open surgery was 39%, 33%, or 4%, respectively. As theoretical risk of LESS was raised, preference for LESS decreased, whereas preference for laparoscopy and open surgery increased. Study limitations are a nonrandomized design and the use of a nonvalidated scale. CONCLUSIONS Urologic patients favor LESS cosmesis outcomes over those for laparoscopy or open surgery. Considering the superior scar satisfaction among LESS patients, who were younger and more likely to be undergoing surgery for benign disease, we infer that this demographic most values the cosmetic advantages of LESS.

Comparison of renal ablation with cryotherapy, dry radiofrequency, and saline augmented radiofrequency in a porcine model.

BACKGROUND Needle ablative therapy has recently generated a lot of interest in the urologic community. We compare renal lesions produced in a porcine model using three forms of needle ablative energy: cryoablation (CR), dry radiofrequency (RF), and saline augmented radiofrequency (SARF). STUDY DESIGN In 10 farm pigs, under ultrasonographic guidance, 40 laparoscopic renal lesions were produced: 825-mm CR lesions were produced with 2.4-mm cryoprobes (Endocare Inc, Irvine, CA), after 1-mL preinfusions of 14.6% saline, 12 SARF lesions were created with 22-gauge needles (2 mL/minute 14.6% saline, 50 W 510 kHz RF for 60 seconds), 12 RF lesions were created with a 2-cm array LeVeen electrode and an RF2000 generator using impedance limited 30 to 60 W double activations (Radiotherapeutics Corp, Mountain View, CA), and 8 RF lesions were produced using 22-gauge needles and double 10 W activations with the RF2000 generator. Eight animals were sacrificed after 1 week for acute pathology. An additional two animals were sacrificed at 8 weeks to provide chronic pathology results for the LeVeen dry RF and SARF modalities. RESULTS CR produced a regular 18- to 22-mm zone of complete necrosis bordered by a 1.5- to 2.5-mm zone of partial necrosis. Acutely, LeVeen RF and single-needle RF produced lesions 25 to 45 mm and 6 to 10 mm wide, respectively. Acutely, SARF produced irregular cone-shaped lesions 15 to 31 mm wide. Only one of eight acute LeVeen RF lesions showed complete necrosis; none of the four 8-week LeVeen RF lesions displayed complete necrosis. Two of the four 8-week SARF lesions displayed complete necrosis. The remainder of the LeVeen RF, single-needle RF, and SARF lesions showed early, indeterminate tubular damage with relative glomerular sparing and bands of complete necrosis (0.5 to 1.5 mm) and inflammation (0.5 to 2 mm) at the periphery. Only CR could be consistently monitored with laparoscopic ultrasonography. CONCLUSIONS Renal cryoablation produces well-defined, completely necrotic lesions that can be monitored reliably with ultrasonography. Longer followup may be required to characterize the full extent of renal necrosis produced by RF, but in the short run, none of the RF modalities reliably produced 100% necrosis in all cases.

Evaluation of the use of a biodegradable ureteral stent after retrograde endopyelotomy in a porcine model.

PURPOSE We evaluated the use of a poly-L-lactide-co-glycolide (PLGA) bioabsorbable ureteral stent after Acucise balloon incision (Applied Medical Resources, Rancho Santa Magarita, California) endopyelotomy in a porcine model. MATERIALS AND METHODS After unilateral Acucise endopyelotomy in 9 female Yucatan minipigs a self-reinforced PLGA stent was placed in 5 (group 1) and a 7Fr double pigtail Percuflex stent (Boston Scientific, Natick, Massachusetts) was placed in 4 (group 2). Preoperatively, and 6 and 12 weeks postoperatively plain x-ray of the kidneys, ureters and bladder, cystography, side specific creatinine clearance and retrograde ureterography were done. The contralateral ureters served as untreated controls. The 7Fr stents were removed at 6 weeks. All animals were sacrificed at 12 weeks after bilateral flow studies. Histological specimens from 4 sites along the urinary tract were graded on a healing score of 0-normal, to 3-severe changes. RESULTS Side specific creatinine clearance was similar to preoperative values at 6 and 12 weeks. At the 2 time points plain x-ray of the kidneys, ureters and bladder in group 1 showed retroperitoneal stent fragments in 3 of the 5 animals, which was confirmed at autopsy. Retrograde ureterography in group 1 showed mild hydronephrosis in all 5 ureters and saccular diverticula in 4, which was similar in 2 and 3 animals, respectively, in group 2. Cystography demonstrated grades 1 to 2 reflux in 2 animals at 6 weeks but none at 12 weeks in group 1 and no reflux at either time point in group 2. Flow rates and healing scores were statistically similar in the 2 groups but the latter trended toward less favorable healing of ureteral musculature with application of the absorbable stent. CONCLUSIONS In this pilot study the use of self-reinforced PLGA biodegradable ureteral stents was feasible after Acucise endopyelotomy in a porcine model with radiographic and fluid flow results that were relatively similar to those of standard 7Fr stents but with less favorable biocompatibility.

Perioperative Comparison of Robotic Assisted Laparoendoscopic Single-Site (LESS) Pyeloplasty Versus Conventional LESS Pyeloplasty

BACKGROUND Conventional laparoendoscopic single-site (C-LESS) pyeloplasty is technically challenging due to instrument clashing, loss of triangulation, and difficulty sewing. Application of the da Vinci S or Si robotic platforms could potentially overcome these challenges. OBJECTIVE Compare our initial experience with robotic assisted laparoendoscopic single-site (R-LESS) pyeloplasty to our latter experience with C-LESS pyeloplasty (ie, after the initial 15 patients). DESIGN, SETTING, AND PARTICIPANTS This single-institution retrospective observational cohort study involved consecutive patients who presented with symptomatic ureteropelvic junction obstruction and who were deemed suitable for single-incision pyeloplasty by the treating surgeon. MEASUREMENTS Demographic, clinical, perioperative, and early postoperative comparative outcomes. RESULTS AND LIMITATIONS Ten patients each underwent R-LESS or C-LESS pyeloplasty by a single surgeon between March 2009 and July 2011. For R-LESS and C-LESS groups, age, gender distribution, body mass index, proportion of patients with prior abdominal surgery, estimated blood loss, and hospital length of stay were statistically similar. Mean operative time was significantly longer for R-LESS (226 vs 188 min; p=0.007). C-LESS pyeloplasty alone required an accessory port for the anastomosis in 10 of 10 cases. Two conversions to standard laparoscopy and two postoperative complications occurred in 3 of 10 patients in the C-LESS group, compared with no conversions and one postoperative complication in the R-LESS group (p=0.26). Study limitations are a retrospective design, a modest number of patients, and a lack of quantification of subjective outcomes such as instrument clashing and maneuverability. CONCLUSIONS Adaptation of the da Vinci Si robotic surgical platform to laparoendoscopic single-site pyeloplasty appears to reduce the physical learning curve for this complex procedure. Future prospective, comprehensive evaluation of additional outcomes including subjective parameters, cosmesis, and longer term functional outcomes will help better define its role in minimally invasive dismembered pyeloplasty and better estimate its associated learning curve.

Importance of cosmesis to patients undergoing renal surgery: a comparison of laparoendoscopic single-site (LESS), laparoscopic and open surgery

Study Type – Therapy (case series)