Peter M. Knapp

Extracorporeal Shock Wave Lithotripsy Induced Perirenal Hematomas

Subcapsular or perirenal bleeding is the most commonly experienced adverse effect directly attributable to externally applied shock waves. The first consecutive 3,620 extracorporeal shock wave lithotripsy treatments with the HM3 Dornier lithotriptor at our institution resulted in 24 hematomas in 21 patients, for an incidence of 0.66 per cent. Various factors associated with treatment were examined. The number of shock waves (up to 2,000) and voltage up to 24 kv. did not correlate with the development of hematoma. Coagulation studies were normal in all patients with hematomas. There was no correlation of patients size and weight, or stone size, number or location with the occurrence rate of perinephric hematoma. Patients with pre-existing hypertension, particularly those with unsatisfactory control of hypertension, had a significantly increased incidence of perinephric hematoma. The incidence of hematoma in hypertensive patients was 2.5 per cent and it increased to 3.8 per cent in patients with unsatisfactory control of hypertension. Therefore, pre-existing hypertension is a significant risk factor in the occurrence of post-extracorporeal shock wave lithotripsy bleeding. The incidence of perinephric hematoma also was increased in patients with pre-treatment urinary tract infection and those who underwent simultaneous bilateral treatment. Management of post-extracorporeal shock wave lithotripsy bleeding generally is conservative although a third of the patients required transfusion.

Extracorporeal Shock Wave Lithotripsy Experience in Children

Extracorporeal shock wave lithotripsy treatment for calculi of the upper urinary tract was performed in 15 children between 3 and 17 years old. Success was achieved in 93 per cent of the cases (72 per cent were free of stone and 21 per cent had insignificant fragments). No major complications were encountered in the series.

Evolution of the technique of combination therapy for staghorn calculi: a decreasing role for extracorporeal shock wave lithotripsy.

Percutaneous nephrostolithotomy with or without extracorporeal shock wave lithotripsy (ESWL) has been extensively used in the management of staghorn calculi, with stone-free rates varying from 23 to 86%. Explanations for the variability of such results include differences in stone burden, differences in percutaneous techniques and an overreliance on ESWL. The results and changing trends in the relative roles of percutaneous nephrostolithotomy and ESWL in the management of staghorn calculi at the Methodist Hospital of Indiana were examined. We reviewed 343 cases of staghorn calculi (partial and complete) with adequate followup data, which were managed with initial percutaneous nephrostolithotomy. Cases were divided into 2 groups: group 1 (252 cases) from 1984 to 1987 when access was performed by a radiologist and group 2 (91 cases) from 1988 to 1990 when access was performed by a urologist. Although stones in group 2 tended to be larger, a decreasing dependence on ESWL was noted (64.7% in group 1 compared to 35.2% in group 2, p less than 0.001). Despite the larger stone size in group 2, stone-free rates were similar (83.3% in group 1, 86.8% in group 2). In groups 1 and 2 percutaneous nephrostolithotomy alone achieved stone-free rates of 91% and 91.5%, respectively. The stone-free rate with the combination approach was 79.1% and 78.1% in groups 1 and 2, respectively. Technical refinements with percutaneous nephrostolithotomy in group 2 include accurate and carefully selected accesses (superior pole in 36.3%) for best approach to the stone, multiple accesses (13.3%) and improved skills in flexible nephroscopy. Blood transfusion has not been required in group 2 compared with 11.1% in group 1. Mean hospital stay was 12.4 days in group 1 and 10.3 days in group 2 (percutaneous nephrostolithotomy alone, 7.2 days). With careful attention to percutaneous nephrostolithotomy techniques, complex renal stones can be successfully managed endourologically, reducing the need for combination ESWL. Complications previously associated with percutaneous nephrostolithotomy have decreased.

Establishment of a Urological Surgery Quality Collaborative

PURPOSE We describe the establishment of the Urological Surgery Quality Collaborative including our pilot project to improve radiographic staging for men with prostate cancer. MATERIALS AND METHODS The Urological Surgery Quality Collaborative comprises more than 60 urologists from 3 group practices. From May through September 2009 Urological Surgery Quality Collaborative surgeons collected a uniform set of data (eg prostate specific antigen, clinical stage) for men with newly diagnosed prostate cancer. After categorizing the cancer of each patient as low, intermediate or high risk, we analyzed baseline use of staging studies across prostate cancer risk strata and Urological Surgery Quality Collaborative practice locations. RESULTS Of 215 men with prostate cancer 34%, 42% and 24% had low, intermediate and high risk cancer, respectively. Overall 44% and 43% of patients underwent staging with a bone scan or computerized tomography, respectively, and only 9% and 7% of these studies, respectively, were positive for metastases. Use of staging studies increased across risk strata as bone scans or computerized tomography were performed in 17% and 18%, 41% and 40%, and 88% and 86% of patients, respectively, with low, intermediate and high risk tumors (p<0.01). For men with low risk prostate cancer the use of bone scans and computerized tomography differed significantly across Urological Surgery Quality Collaborative practices (p<0.01) and for this group only 1 bone scan (and no computerized tomography) was positive for metastases. CONCLUSIONS Use of staging evaluations varies by prostate cancer risk strata and across Urological Surgery Quality Collaborative practices. By feeding these data back to surgeons we may be able to improve practice patterns and avoid unnecessary studies in low risk patients. Attainment of this goal would establish the Urological Surgery Quality Collaborative as a viable infrastructure for collaborative quality improvement in urology.

Practice Based Collaboration to Improve the Use of Immediate Intravesical Therapy after Resection of Nonmuscle Invasive Bladder Cancer

PURPOSE Perioperative instillation of intravesical chemotherapy after bladder tumor resection is supported by level I evidence showing a 30% decrease in tumor recurrence. However, studies of administrative data sets show poor use in practice. MATERIALS AND METHODS We prospectively evaluated the use of perioperative intravesical chemotherapy in a multipractice quality improvement collaborative. Cases were categorized as ideal for intravesical chemotherapy (1 or 2 papillary tumors, cTa/cT1 and completely resected) and nonideal. The reasons for not administering intravesical chemotherapy in ideal cases were classified as appropriate or modifiable. Before and after comparative feedback and educational interventions we calculated judicious use of intravesical chemotherapy (nonuse in nonideal cases plus use in ideal cases plus appropriate nonuse in ideal cases) and quality improvement potential (use in nonideal cases plus nonuse in ideal cases attributable to modifiable factors). RESULTS We accrued a total of 2,794 cases at the 5 sites in 22 months. The rate of use in ideal cases was 38% before and 34.8% after intervention (p=0.36), while use in nonideal cases decreased from 15% to 12% (p=0.08). Overall, intravesical chemotherapy was used judiciously in 83.0% to 85.7% of cases, while the remaining 14.3% to 17.0% represented quality improvement potential. CONCLUSIONS Judicious use of perioperative intravesical chemotherapy is relatively high in routine practice. Most instances of nonuse represent appropriate clinical judgment. Utilization did not change after quality improvement interventions, suggesting that there may a ceiling effect that makes it difficult to improve care that is high quality at baseline. Moreover, decreasing unnecessary use of an intervention may be easier than encouraging appropriate use of potentially toxic therapy.

Understanding the Use of Immediate Intravesical Chemotherapy for Patients with Bladder Cancer

PURPOSE Despite its established efficacy in reducing recurrence rates for patients with urothelial carcinoma, immediate intravesical chemotherapy is reportedly used infrequently. Accordingly, the Urological Surgery Quality Collaborative implemented a project aimed at understanding and improving the use of immediate intravesical chemotherapy. MATERIALS AND METHODS Surgeons in 5 Urological Surgery Quality Collaborative practices prospectively collected clinical and baseline intravesical chemotherapy use data for patients undergoing bladder biopsy or transurethral bladder tumor resection from September 2010 through January 2012. In the second phase of data collection (June 2011 through January 2012) treating surgeons also documented reasons for not administering intravesical chemotherapy. We defined patients with 1 to 2 clinical stage Ta/T1, completely resected, papillary tumor(s) as ideal candidates for treatment with immediate intravesical chemotherapy. For ideal and nonideal patients we examined baseline use of intravesical chemotherapy across Urological Surgery Quality Collaborative practices as well as reasons for not administering therapy among ideal patients. RESULTS Among 1,931 patients 37.2% met criteria as ideal cases for intravesical chemotherapy administration. We observed significant variation in the use of intravesical chemotherapy across Urological Surgery Quality Collaborative practices for ideal (range 27% to 50%) and nonideal cases (9% to 24%) (p <0.001). Reasons for not treating ideal candidates included lack of confirmation of malignancy (4, 2.8%), uncertainty regarding the benefits of intravesical chemotherapy (28, 19.6%) and logistic factors such as the unavailability of medication (34, 23.8%). CONCLUSIONS Use of immediate intravesical chemotherapy by Urological Surgery Quality Collaborative practices is higher than reported elsewhere but still varies widely, even among ideal candidates. Efforts to optimize use will be aided by disseminating evidence supporting indications and benefits of intravesical chemotherapy, and by addressing local logistic factors that limit access to this evidence-based therapy.

Extracorporeal Shock Wave Lithotripsy in Patients with a Solitary Kidney

Extracorporeal shock wave lithotripsy was used to treat 68 patients with renal calculi in a solitary kidney. Epidemiological information, including stone number, size and location, was similar to that of other patients treated with extracorporeal shock wave lithotripsy. Renal function as measured by serum creatinine changed negligibly in the majority of the patients. Three patients had transient serum creatinine elevations greater than 2 mg. per dl. that were caused by obstruction from stone fragments. There were 2 perirenal hematomas that required transfusion. One patient required retrograde manipulation of a ureteral stone before extracorporeal shock wave lithotripsy, while 6 required stone manipulations after therapy for steinstrasses. Of 59 patients evaluable after extracorporeal shock wave lithotripsy 58 (98.3 per cent) had a successful result: 38 (64.4 per cent) were completely free of stones and 20 (33.9 per cent) had clinically insignificant residual fragments. Extracorporeal shock wave lithotripsy is effective and safe in a solitary renal unit. We believe that in most patients it is the procedure of choice. Attention to fever, urine output and fragment size perioperatively is crucial.

Extracorporeal Shock Wave Lithotripsy

Extracorporeal shock-wave lithotripsy has been proposed a s a modality to facilitate the removal of bone cement during revision arthroplasty; however, concomitant cortical microfractures have been reported. The current study examines the effect on whole bone strength of extracorporeal shock-wave lithotripsy directed a t the cementbone complex. Canine femora were subjected to manual cement extraction or lithotripsy followed by manual cement extraction. Contralateral femora served as controls. Torsional fractures were created, and maximum torque, maximum angular displacement, and energy capacity to failure were determined. Although cement extraction alone reduced mean torque by 6.6% and failed to reduce mean torque angle or mean energy capacity, the combination of lithotripsy and cement extraction reduced mean torque by 7.3470, mean torque angle by 14.3%, and mean energy capacity by 18.3%. No statistical significance was demonstrated between the two groups in torque, angle, or energy capacity. At magnitudes and numbers of shock waves previously shown to significant11 reduce cement-bone interface mechanical strength, lithotripsy exposure had a minimal and insignificant effect on whole bone strength.

Extracorporeal Shock-Wave Lithotripsy

Analysis of our data clearly demonstrates that morbidity, secondary treatment, post-treatment manipulations, and failure of treatment increase as the stone size increases because of the increased stone fragment burden. Patients whose stone burden was less than 2 cm clearly had less morbidity. Composition of the stone may also alter the success of treatment (with cystine, calcium oxalate monohydrate, and brushite stones being resistant to treatment). However, post-treatment morbidity and complications were observed in all categories. Perirenal hematomas are unpredictable by current preoperative testing. Obstruction with pain can occur any time after treatment but usually occurs within the first 48 hours in the majority of patients. Only 1 per cent of our patients required hospitalization in another institution after discharge. Ambulatory ESWL requires that staff at the facility or a urologist be able to observe and appropriately follow the patient for 24 to 48 hours after treatment.

Extracorporeal Shock Wave Lithotripsy Using Only Intravenous Analgesia with an Unmodified Dornier HM3 Lithotripter

The original Dornier HM3 lithotripter required general or regional anesthesia for virtually all patients. Treatment at lower pressures can be accomplished with this machine by reducing the kilovoltage (kV) to 12 kV to 16 kV, allowing treatment using intravenous sedation alone. Many patients with single or multiple stones of low to medium volume can be successfully treated with this new technique. General or regional anesthesia is reserved for patients requiring auxiliary procedures (i.e., retrograde stone manipulation, placement of ureteral stents), for patients with large stone volume or dense stones, for patients with a known high incidence of retreatment, or by patient preference. One hundred fifteen patients treated with this new approach are compared to previous experience with the HM3 utilizing 18 kV to 24 kV and general or regional anesthesia.