Serum creatinine can be used as a surrogate for glomerular filtration rate in single renal unit models

BACKGROUND AND PURPOSE

Single renal unit models are invaluable for studies in renal physiology, transplantation and response to ischemic injury. Glomerular filtration rate (GFR) is commonly used for evaluation of renal function. Measuring the GFR involves relatively complicated and expensive systems. In this study we determined whether serum creatinine (Scr) can predict the GFR in this model.

MATERIALS AND METHODS

Right laparoscopic nephrectomy was performed in 46 female pigs weighing 25 kg-30 kg. Twelve days later the left kidney was exposed to various periods of warm ischemia (30, 60, 90, and 120 minutes). Scr and GFR (using the iohexol clearance method) were determined preoperatively and at postoperative days 1, 3, 8, 15, 22 and 29. A total of 244 pairs of Scr and GFR values were analyzed to determine a formula for predicting GFR (pGFR) from Scr.

RESULTS

Scr range was 1.2 mg/dl -29 mg/dl and GFR range was 1.8 ml/min -180.5 ml/min. The empiric formula deduced from the database for calculating pGFR from Scr was: pGFR = (217 divided by Scr) minus 0.2. pGFR correlated well with the actual GFR (R(2) = 0.85). The graphs for pGFR were almost indistinguishable from the graphs for actual GFR in every single animal. The results and conclusions of the experiments using either actual or predicted GFR were identical.

CONCLUSIONS

We conclude that in a single renal unit porcine model using ischemia as the insult to the kidney, expensive actual measurements of GFR can be reliably replaced by Scr based calculated GFR.

Comparison of laparoscopic and open partial nephrectomy in clinical T1a renal tumors

PURPOSE

Partial nephrectomy has been established as a standard of care for T(1a) renal tumors. Laparoscopic partial nephrectomy (LPN) has been described as more difficult to perform than open partial nephrectomy (OPN). We compare our series of LPN and OPN.

PATIENTS AND METHODS

From October 2002 to January 2006, 76 LPNs were performed for patients with clinical T(1a) tumors. These patients were matched with a cohort of patients who underwent OPN for solitary tumors of 4 cm or smaller in diameter. The cohorts were compared with regard to demographics, perioperative data, and outcomes.

RESULTS

The patient populations were demographically similar. Although mean tumor size was smaller in the laparoscopic cohort (2.5 v 2.9 cm, P=0.002), the OPN cohort demonstrated shorter operative (193 v 225 min, P=0.004) and ischemia times (20.5 v 32.8 min). LPN was associated with less blood loss (212 v 385 mL, P<0.001) and shorter hospital stay (2.5 v 5.6 days, P<0.001), however. One positive margin occurred in each of the LPN and OPN cohorts. Intraoperative complications were similar, although LPN was associated with fewer postoperative complications. Of note, two LPN (2.6%) patients had emergent reoperation and complete nephrectomy because of postoperative hemorrhage.

CONCLUSIONS

Despite increased operative and ischemia times, LPN patients demonstrated quicker recovery and fewer postoperative complications. Two patients in the LPN group, however, had emergent complete nephrectomy because of hemorrhage. We conclude that LPN is still an evolving alternative to OPN in patients with small renal tumors.

Efficacy of the argon beam coagulator alone in obtaining hemostasis after laparoscopic porcine heminephrectomy: a pilot study

INTRODUCTION

The argon beam coagulator (ABC) is used in combination with other hemostatic agents and suture renorrhaphy to obtain hemostasis after laparoscopic partial nephrectomy. We performed a pilot study evaluating the efficacy of the ABC-alone in obtaining hemostasis during laparoscopic heminephrectomy (LHN) in a porcine model.

METHODS

Eight pigs (4 small (30 kg-40 kg) and 4 large (70 kg-80 kg)), underwent bilateral LHN. Hemostasis then was obtained by using the ABC at 120W as a single modality. The collecting system was not repaired. The hilum was unclamped and the renal defect observed for 20 minutes with pneumoperitoneum pressure of 4 mmHg. The animals were survived for 24 hours at which time they were sacrificed and necropsy performed.

RESULTS

All small pigs underwent LHN successfully. Mean pre- and post-op Hgb were 11.2 g/dl and 9.8 g/dl, respectively (p=0.12). In one of the animals, ABC at 150W was required to obtain hemostasis. All but one of the large pigs underwent LHN successfully. One of the animals had continuous bleeding despite ABC after right LHN and a completion nephrectomy was performed. Pre and postoperative Hgb for the large pigs were 9.9 g/dl and 9.3 g/dl, respectively (p=0.24).

CONCLUSIONS

The ABC-alone was successful in obtaining hemostasis in all but two of the renal units in both small and large pigs. The two hemostatic failures were noticeable immediately after hilar unclamping. Our data suggest that ABC-alone provides adequate hemostasis when applied to small-caliber vessels. Further long term studies are needed to fully evaluate the efficacy of the ABC.

Surgeons' perceptions and injuries during and after urologic laparoscopic surgery

OBJECTIVES

The biomechanical and mental strains placed on the surgeon while performing laparoscopic procedures are significantly higher compared with open surgical techniques. We undertook this study to assess the prevalence of surgeons' deleterious perceptions or injuries related to laparoscopic urologic surgery.

METHODS

Members of endourological society were mailed a questionnaire evaluating their laparoscopic experience, total number of standard laparoscopic surgeries (SLS), hand-assisted laparoscopic surgeries (HALS), and robotic-assisted laparoscopic surgeries (RALS) they performed. The subjects reported any neuromuscular or arthritic injuries sustained during laparoscopic surgery, and graded the degree of pain, numbness, and fatigue they experienced.

RESULTS

A total of 73 urologists completed the questionnaires. The average responder was 44 years old, had completed a median of 117 procedures, and was performing 3 laparoscopic surgeries per week. Neuromuscular or arthritic symptoms during surgery were reported by 22 responders (30%), the most common was finger paresthesia (18%). At the conclusion of HALS, 45% of the surgeons suffered from hand and wrist numbness and 37% reported pain in these areas. A significant association was observed between the risk of sustaining injury during surgery and the total number of laparoscopic procedures performed by the responder (P = 0.016). RALS was the procedure least associated with injuries, and HALS the most.

CONCLUSIONS

The laparoscopic operating theater is a hostile ergonomic environment. Surgeons' awareness of the common injuries associated with laparoscopic surgery and careful equipment adjustments before surgery are mandatory to minimize injury. Future improvements in instrument design according to ergonomic principles are highly warranted.

Predicting the risk of patients with biopsy Gleason score 6 to harbor a higher grade cancer

PURPOSE

Prostate cancer Gleason score 3 + 3 = 6 is currently the most common score assigned on prostatic biopsies. We analyzed the clinical variables that predict the likelihood of a patient with biopsy Gleason score 6 to harbor a higher grade tumor.

MATERIALS AND METHODS

The study population consisted of 448 patients with a mean age of 59.1 years who underwent radical prostatectomy between February 2003 to October 2006 for Gleason score 6 adenocarcinoma. The effect of preoperative variables on the probability of a Gleason score upgrade on final pathological evaluation was evaluated using logistic regression, and classification and regression tree analysis.

RESULTS

Gleason score upgrade was found in 91 of 448 patients (20.3%). Logistic regression showed that only serum prostate specific antigen and the greatest percent of cancer in a core were significantly associated with a score upgrade (p = 0.0014 and 0.023, respectively). Classification and regression tree analysis showed that the risk of a Gleason score upgrade was 62% when serum prostate specific antigen was higher than 12 ng/ml and 18% when serum prostate specific antigen was 12 ng/ml or less. In patients with serum prostate specific antigen lower than 12 ng/ml the risk of a score upgrade could be dichotomized at a greatest percent of cancer in a core of 5%. The risk was 22.6% and 10.5% when the greatest percent of cancer in a core was higher than 5% and 5% or lower, respectively.

CONCLUSIONS

The probability of patients with a prostate biopsy Gleason score of 6 to conceal a Gleason score of 7 or higher can be predicted using serum prostate specific antigen and the greatest percent of cancer in a core. With these parameters it is possible to predict upgrade rates as high as 62% and as low as 10.5%.

Evolution of Robotic Surgery in the Treatment of Localized Prostate Cancer

Adenocarcinoma of the prostate is the second most common cancer in men in the United States (following only skin cancer) and accounts for 33% of all newly diagnosed male cancers. It is estimated that in 2007, 218,890 men will be diagnosed with prostate cancer and 27,050 will die from this disease. While most currently diagnosed prostate cancers are localized, radical prostatectomy remains a gold standard treatment. Since its original description, radical retropubic prostatectomy has evolved over the last three decades to a precise, sophisticated procedure with minimal mortality, and excellent surgical outcomes. However, despite its efficacy, open surgical treatment is inherently associated with blood loss and significant pain. Due to these reasons, many men have sought other, less invasive forms of treatment. With its development in the late 1990s, minimally invasive surgery has significantly and irrevocably changed the surgical treatment of prostate cancer. Robotic-assisted technology has further propelled the utilization of the laparoscopic approach for radical prostatectomy, particularly for non-laparoscopic trained surgeons. The implementation of robotic technology has been rapid. Presently, 7 years after its approval by the FDA, many hospitals have established for robotic-assisted radical prostatectomy programs. This trend will undoubtedly continue to grow as more surgeons become familiar with the procedure, more robotic systems become available, and increasingly mature data is published. Robotic-assisted laparoscopic radical prostatectomy allows patients the benefits of minimally invasive surgery with functional and oncological results comparable to those from open and standard laparoscopic procedures, we believe that this surgical approach will shortly evolve into the standard surgical approach for localized prostate cancer.

Cystectomy in the ninth decade: operative results and long-term survival outcomes

INTRODUCTION

Radical cystectomy (RC) with urinary diversion remains as one of the more complex urological procedures despite considerable progress in surgical technique. Increasing patient age, along with associated age-related comorbidities, may portend a poor outcome in those undergoing such complicated surgical procedures. Herein, we report our experience with radical cystectomy in the elderly population.

METHODS

We retrospectively reviewed our RC results from 1995 to 2003. Patients >or = 80 years old were included in this analysis. Perioperative outcomes, as well as overall and disease-free survival were evaluated.

RESULTS

A total of 517 patients underwent RC with urinary diversion during this time period. Forty-nine (9.5%) patients were >or= 80 years old. Mean age and BMI were 83.4 years (range 80-94) and 27.1kg/m2 (range 17.4-39.0), respectively. Eighty-three percent of the patients had >or= 1 comorbidities and 67% had a significant smoking history. Mean operative time and estimated blood loss were 279 minutes and 985 ml, respectively. Thirty-two patients (76%) required blood transfusion in the perioperative period. Among patients found to have urothelial cancer a pathological analysis (36), 21 patients (58%) had < pT3a while 15 patients (42%) had >or= pT3b or >or= N1. Intraoperative complications (5%) included one large bowel injury and hypogastric artery laceration. Thirty- and 90-day mortality rates were 9.5% and 11%, respectively. Early and late postoperative complications were 57% and 17% and 5-year overall and disease-free survival were 44% and 36%, respectively.

CONCLUSIONS

Radical cystectomy with urinary diversion in patients >or= 80 years old is related with significant short-term and long-term morbidity. Proper patient selection assessing performance status and psychosocial parameters appear to optimize survival outcomes. However, regardless of age, timely surgical management for localized disease control is essential for ultimate sustained disease-free survival.

Difficult decisions in urologic oncology: Management of high-grade T1 transitional cell carcinoma of the bladder

Management decisions for a patient with high grade (G3) T1 urothelial cancer of the bladder are critical. These tumors should not be classified as "superficial" since they are not confined to the urothelium. Patients with T1G3 bladder cancers are likely to have recurrence and the tumor will often progress, invade, metastasize, and cause death. Radical cystectomy as well as transurethral resection followed by intravesical BCG are acceptable initial therapies. This article reviews these treatment options and provides recommendations for management of high grade T1 tumors.

Operative Outcomes of Upper Pole Laparoscopic Partial Nephrectomy: Comparison of Lower Pole Laparoscopic and Upper Pole Open Partial Nephrectomy

OBJECTIVES

The intraoperative complexity of laparoscopic partial nephrectomy (LPN) for upper pole renal tumors is recognized. We report on the technical feasibility and operative outcomes of LPN for upper pole tumors (UPLPN) and lower pole tumors (LPLPN), and open partial nephrectomy (UPOPN) for upper pole tumors.

METHODS

We retrospectively reviewed our database of LPNs performed by a single surgeon from October 2002 to February 2006. All solitary, upper and lower pole tumors in patients with a normal contralateral kidney were included. The perioperative outcomes were assessed. UPOPNs performed in the same institution by a separate surgeon were analyzed and compared separately with the UPLPN group.

RESULTS

Three groups, UPLPN (20 patients), LPLPN (33 patients), and UPOPN (24 patients), were analyzed. The UPLPN and LPLPN groups had similar perioperative outcomes. The intraoperative and postoperative major complications were also comparable between the UPLPN and LPLPN groups (17% versus 12%, P = 0.68 and 22% versus 6%, P = 0.07, respectively). The mean pathologic tumor size was larger (3.2 versus 2.3 cm, P = 0.05) and the mean operative time significantly shorter (187 versus 244 minutes, P = 0.02) in the UPOPN group than in the UPLPN group. The UPOPN group had a trend toward fewer intraoperative complications compared with the UPLPN group (4% versus 17%, P = 0.17). The final pathologic surgical margins were negative in all three groups.

CONCLUSIONS

LPN for upper pole renal tumors is technically feasible and may have comparable outcomes to LPN for lower pole tumors. However, performing open nephron-sparing surgery is still the standard of care because it may offer fewer complications and reduce the risk of ischemic damage to the kidney.

Impact of surgical margin status on long-term cancer control after radical prostatectomy

OBJECTIVE

To determine whether previously described technical modifications that significantly decreased the positive surgical margin (PSM) rate have translated into improved long-term cancer control, as SM status is generally recognized as an independent risk factor for biochemical recurrence (BR) after radical retropubic prostatectomy (RRP), and is the only factor that can be modified by surgical technique.

PATIENTS AND METHODS

Between March 1994 and December 2004, 996 consecutive patients had RRP as the sole treatment for clinically localized prostate cancer. The surgery was done by one surgeon (C.B.B.) and the data were prospectively reviewed.

RESULTS

The overall PSM rate was 8.8%; the PSM rate by pathological stage was 1.7%, 24.2% and 27.1% for men with pT2, pT3a and pT3b disease, respectively (P < 0.001). In all, 968 of 996 (97.2%) patients were available for the follow-up (mean 6.4 years); 69 of 883 (7.8%) with negative SMs (NSMs) developed BR, vs 29 of 85 (34%) with PSMs (P < 0.001). The actuarial 5- and 10-year biochemical disease-free survival was 92.1% and 89.6%, and 70.6% and 59.9%, for patients with NSM and PSM, respectively (P < 0.001). On multivariate analysis, PSM, pathological stage and Gleason grade were the strongest predictors of BR (P < 0.001). The preoperative prostate-specific antigen level, and clinical stage T1c and T2a disease were not associated with recurrence. The hazard ratio (95% confidence interval) for BR in patients with PSMs was 3.27 (2.1-5.1).

CONCLUSIONS

RRP including the previously described surgical modifications not only decreased the PSM rate but also resulted in excellent long-term cancer control. The importance of meticulous surgical technique in RRP cannot be overemphasised.