Quantitation of shock wave lithotripsy-induced lesion in small and large pig kidneys

BACKGROUND

Shock wave lithotripsy (SWL) is known to cause injury to the kidney. However, it is not known how lesion size varies as the parameters of SWL treatment (number of shocks, kilovoltage, kidney size) are changed. This hypothesis could not be tested because there was no method available to quantitate accurately the SWL-induced renal lesion.

METHODS

A dosage of 2,000 shocks at 24 kV delivered by an unmodified Dornier HM3 lithotripter was applied to the lower pole calyx of the right kidney of small and large pig kidneys. A new method was developed to embed a whole pig kidney for serially sectioning, recording, and digitization. Automated computer color recognition made it possible to discriminate regions of hemorrhage from undamaged tissue and allowed quantitation of the lesion in single sections and in the entire kidney.

RESULTS

The new protocol resulted in an accurate identification of sites of hemorrhage and calculations of the volume fraction of injured renal tissue. Lesion size induced in small kidneys was significantly larger than that induced in the larger kidneys (7.6 +/- 1.2% and 1.6 +/- 0.7%, respectively).

CONCLUSIONS

Computer segmentation of serially sectioned SWL-treated kidneys has determined that kidney size is a risk factor for enhanced renal injury.

Urologic applications of the Holmium laser

The Holmium laser has now been in clinical use in urology for several years. The indications for its use continue to expand, and now include lithotripsy and urothelial tumor ablation anywhere in the urinary tract, resection of the prostate, incision of various urinary tract strictures, and vaporization of cutaneous lesions of the external genitalia. The 2100-nm wavelength provides the Holmium laser with a unique combination of vaporization and coagulation, allowing a precise cutting action when higher energy levels are applied. A shallow depth of penetration (< 0.5 mm) in water and tissue allows precise energy application and provides a margin of safety. The machine's user-friendly setup facilitates its operation by urologists and assistance by allied health-care personnel. The multiple urologic applications make the Holmium laser an attractive instrument for everyday utilization by any medium to large urological unit.

Effects of SWL on glomerular filtration rate and renal plasma flow in uninephrectomized minipigs

This study tested the hypothesis that the effects of SWL on hemodynamics in solitary kidneys differ from those in kidneys of binephric animals. Five female miniature pigs (Pitman-Moore, 6 months of age, 30-35 kg) were anesthetized for unilateral nephrectomy. Seven pigs served as binephric controls. Two weeks later, each pig was anesthetized, prepared for unilateral or bilateral urine collections, and subjected to SWL (Dornier HM3, 2000 shocks, 24 kV). Clearances of inulin (glomerular filtration rate; GFR) and para-aminohippurate (renal plasma flow; RPF) were measured 1 hour prior to and 1, 4, and 24 hours after SWL. The GFR and RPF were higher in uninephrectomized than in intact pigs at all time points. In both groups, SWL reduced GFR and RPF. In the binephric pigs, RPF was reduced at all times post-SWL, but in the uninephrectomized pigs, RPF was returning toward baseline by 4 hours post-SWL and was not different from baseline at 24 hours. A comparison of whole-animal GFR and RPF (righ plus left clearances in binephric pigs v solitary renal clearances in uninephrectomized pigs) showed that whole-animal GFR and RPF did not differ between the groups before or after SWL. Compensatory renal hypertrophy and improved hemodynamics in solitary kidneys may acutely attenuate the renal vasoconstrictive effect of SWL. The long-term consequences of the compensatory changes are unknown.

Extracorporeal shock wave lithotripsy. Development, instrumentation, and current status

In this article, the author briefly reviews the early development of the lithotriptor, provides a detailed review of lithotriptors that are currently available, and gives an overview of the present extracorporeal shock wave lithotripsy indications and techniques. The author also presents a brief overview of the results that are produced by various lithotriptors.

Branching patterns of the renal artery of the pig

BACKGROUND

The pig kidney is similar in structure and function to the human kideny, thus making it a useful model in understanding the human kidney in health and disease. However, little is known about the branching pattern of the pig renal artery as compared with the human and other animals.

METHODS

The right and left kidneys from 11 juvenile pigs were injected with either Mercox compound to form a vascular cast or contrast media to obtain a renal arteriogram. Branching patterns of the renal artery were then examined to the level of the interlobar arteries.

RESULTS

Examination of all 22 kidneys showed the main stem renal artery branching into two predictable patterns, designated I and II. The renal artery in pattern I (17 of 22 kidneys) divides into upper and lower polar arteries that then form anterior and posterior segmental arteries. Pattern I has two variations. Pattern II (5 of 22 kidneys) has a variable blood flow to the upper pole. Not only do anterior and posterior segmental arteries pass to the upper pole, but additional vessels arising from the lower polar artery also supply the upper pole.

CONCLUSIONS

The most common branching pattern of the main stem renal artery is pattern I, which divides the blood flow of the entire kidney into two distinct regions. Pattern II is less frequently seen and shows more variability in number and location of branches.

Lithotripsy and surgery

Advances in surgical techniques have dramatically altered the management of patients with symptomatic urolithiasis requiring intervention. Extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, and ureteroscopy allow virtually any stone to be removed from the upper urinary tract without resorting to open surgical techniques. Extracorporeal shock wave lithotripsy is the preferred initial treatment for approximately 80% to 85% of calculi. Percutaneous nephrolithotomy is the preferred approach when dealing with more voluminous stone material (ie, > 2 cm). Ureteroscopy is generally reserved for distal ureteral calculi, although the recent advent of small flexible ureteroscopes have extended ureteroscopic techniques effectively into the proximal ureter and even the kidney. Staghorn stones are usually best managed initially with percutaneous nephrolithotomy followed by the addition of extracorporeal shock wave lithotripsy, if necessary. The relative advantages, disadvantages, and complications of extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, and ureteroscopy will be reviewed.

Value of laparoscopy in the management of calculi complicating renal malformations

A minimally invasive approach for urolithiasis patients with complex anatomic abnormalities occasionally necessitates the use of laparoscopic techniques, either alone or in combination with endourologic techniques. The management of these patients is best accomplished in centers with the facilities to provide a spectrum of endourologic and laparoscopic techniques. Two illustrative cases are described.

Use of extracorporeal shock wave lithotripsy for treatment of nephrolithiasis and ureterolithiasis in five dogs

The safety and efficacy of extracorporeal shock wave lithotripsy in 5 dogs with nephrolithiasis and ureterolithiasis was assessed. Three dogs had bilateral nephrolithiasis, 1 had bilateral nephrolithiasis and unilateral ureterolithiasis, and 1 had unilateral nephrolithiasis and unilateral ureterolithiasis. A first-generation lithotriptor was used for all treatments. None of the dogs developed clinically important complications during or after treatment, except for 1 dog treated for bilateral nephrolithiasis that developed transient ureterolithiasis. Renal function was unchanged in all dogs following treatment. Clinical signs resolved in all dogs. Extracorporeal shock wave lithotripsy appears to be a safe and effective means of treating nephrolithiasis and ureterolithiasis in dogs and appears to cause less renal parenchymal damage and renal function loss than does nephrotomy.

Endoscopic management of total ureteral occlusion and ureterovaginal fistula

Between August 1991 and June 1994, endoureterotomy was performed in nine patients for total ureteral occlusion. Four of these patients had an associated ureterovaginal fistula. The total ureteral occlusions were iatrogenic in eight patients and the result of trauma in one. The prone split leg position was used to facilitate simultaneous antegrade and retrograde ureteroscopy in all nine patients. The "cut-to-the-light" technique was utilized in six patients and a new technique employing a fascial incising needle was used in five patients. Five patients developed ureteral strictures within 5 months of the primary procedure that were corrected endoscopically. With a mean follow-up of 22 months, all nine patients have a successful outcome. Endoscopic management of difficult urteral disease such as total urteral occlusion and ureterovaginal fistula is a useful alternative to open surgery.

Shock wave lithotripsy with the Dornier MFL 5000 lithotriptor using an external fixed rate signal

PURPOSE

We examine the effects of fixed rate shock wave administration on the cardiac rhythm and treatment efficacy of a tubless lithotriptor (Dornier MFL 5000*). A secondary goal was to examine the treatment efficacy of fixed shock wave administration compared to R wave triggered lithotripsy.

MATERIALS AND METHODS

In this prospective study Holter monitoring was used before, during and after nonR wave triggered shock wave lithotripsy.

RESULTS

An increase in premature ventricular contractions was noted during shock wave lithotripsy. However, there were no episodes of significant ventricular ectopia, ventricular tachycardia, asystole or heart block as a result of nonR wave triggered shock wave administration. NonR wave gated shock wave lithotripsy expedited patient treatment and (mean treatment time 46 +/- 21 minutes)., minimized the use of sedation during treatment and produced results similar to R wave gated shock wave lithotripsy with the MFL 5000 lithotriptor.

CONCLUSIONS

With adequate precautions, fixed rate shock wave administration would appear to be a reasonable option to treat urolithiasis with the MFL 5000 lithotriptor as with other newer lithotriptors.

Metabolic evaluation of infected renal lithiasis: clinical relevance

Complete metabolic evaluation was performed in 21 patients with infected renal lithiasis. Patients with pure struvite stones (struvite +/- carbonate apatite) were significantly less likely to have metabolic abnormalities than patients who had struvite +/- carbonate apatite+calcium oxalate (2 of 14 v 7 of 7, P = 0.0003). Urine calcium excretion was markedly higher in the mixed stone group than the pure struvite group (342 +/- 98 mg/24 h v 136 +/- 82 mg/24 h; P < 0.0001). The differing opinions among researchers regarding the likelihood of finding metabolic abnormalities in patients with urolithiasis and infection probably reflect differences in the definitions of the populations studied. If patients with calculi containing only struvite +/- carbonate apatite are evaluated, we believe that few significant metabolic abnormalities will be identified.

Percutaneous nephrolithotomy directly through an angiomyolipoma

We present a patient with tuberous sclerosis and bilateral angiomyolipomas with a right partial staghorn calculi in which the calculi was managed with a percutaneous nephrolithotomy. Despite the inherent risk of hemorrhage with a percutaneous approach compounded by the fact that this was done directly through a tumor, we were able to render the patient stone free with no intraoperative bleeding, complications, or the need for postoperative blood transfusion. To our knowledge, this is the first reported case of percutaneous nephrolithotomy directly through a renal angiomyolipoma.

Laparoscopic retroperitoneal needle suspension urethropexy

Recent advances in laparoscopic surgery have allowed urologists to perform laparoscopic bladder suspension; however, laparoscopic suturing techniques have a steep learning curve and make the procedure more difficult and time consuming. We describe a new technique that combines extraperitoneal laparoscopic bladder neck mobilization through a single port with the ease of a needle suspension urethropexy in order to avoid the need for vaginal incisions and the use of laparoscopic suturing techniques. The procedure has been performed in four patients, all of whom are continent and voiding with complete bladder emptying. Postoperative pain was minimal, allowing most patients to be discharged the day after surgery. In the future, the procedure may be performed on an outpatient basis.

Nephrolithiasis Clinical Guidelines Panel summary report on the management of staghorn calculi. The American Urological Association Nephrolithiasis Clinical Guidelines Panel

The American Urological Association Nephrolithiasis Clinical Guidelines Panel recommendations for managing struvite staghorn calculi are based on a comprehensive review of the treatment literature and meta-analysis of outcome data from the 110 pertinent articles containing viable, unduplicated data. The panel concluded that the 3 most significant outcome probabilities are those of being stone-free, undergoing secondary unplanned procedures and having associated complications. Panel guideline recommendations for most standard patients are that neither shock wave lithotripsy monotherapy nor open surgery should be a first-line treatment choice but that a combination of percutaneous stone removal and shock wave lithotripsy should be used.

Biocompatibility of small-intestinal submucosa in urinary tract as augmentation cystoplasty graft and injectable suspension

We explored the biocompatibility of fluidized canine small-intestinal submucosa (SIS) for periureteral injection and as a patch graft for bladder augmentation in pigs. Gross evaluation 8 weeks after submucosal injection showed persistence of the nodule. Histologic examination showed thickened submucosa with spindle cells embedded in poorly organized fibrous material. There was no evidence of inflammatory reaction or granuloma formation. Subserosal nodules likewise persisted and demonstrated capillary ingrowth. Grafts of SIS became epithelialized within 3 weeks with maintenance of bladder capacity. Ingrowth of capillaries and smooth muscle could be seen in later specimens. Although further studies with longer follow-up are needed, SIS appears to be a promising graft material in the urinary tract.

Management of lower pole nephrolithiasis: a critical analysis

The results of extracorporeal shock wave lithotripsy (ESWL*) and percutaneous nephrostolithotomy for the treatment of lower pole nephrolithiasis were examined in 32 consecutive patients undergoing percutaneous nephrostolithotomy at the Methodist Hospital of Indiana and through meta-analysis of publications providing adequate stratification of treatment results. Of 101 cases managed with percutaneous nephrostolithotomy 91 (90%) were stone-free, a result significantly better than that achieved with ESWL (1,733 of 2,927 stone-free, 59%). Stone-free rates with percutaneous nephrostolithotomy were independent of stone burden, whereas stone-free rates with ESWL were inversely correlated to the stone burden treated. The morbidity of patients undergoing percutaneous nephrostolithotomy at our hospital was minimal, with a mean hospital stay of 4.7 +/- 2.8 days. No blood transfusions were required. All patients became stone-free. The percentage of urolithiasis patients with lower pole calculi is increasing. Because of the significantly greater efficacy of percutaneous nephrostolithotomy for lower pole calculi, particularly stones larger than 10 mm. in diameter, further consideration should be given to an initial approach with percutaneous nephrostolithotomy.

Indomethacin suppositories versus intravenously titrated morphine for the treatment of ureteral colic

STUDY OBJECTIVES

To develop a protocol for the blinded IV titration of morphine and to compare the analgesic efficacy and side effect profile of indomethacin suppositories versus IV morphine in the treatment of acute ureteral colic.

DESIGN

Randomized, double-blind, double-dummy, two-period crossover study.

SETTING

Emergency department of a central-city, teaching hospital.

PARTICIPANTS

Patients 18 to 75 years of age with pain suggestive of ureteral colic. Exclusions included pregnancy, adverse reactions to the study drugs, chronic nonsteroidal anti-inflammatory drug (NSAID) therapy, or any pain medicine taken within four hours of ED admission.

INTERVENTIONS

Patients were randomized to one of two groups: indomethacin 100-mg rectal suppository or morphine by IV titration (5-mg loading dose and up to two additional 2.5-mg doses if needed). At the end of 30 minutes, if adequate pain relief had not been obtained, treatment was crossed over.

MEASUREMENTS

Verbal analog scale (initial pain) and visual analog pain relief scale.

MAIN RESULTS

Seventy-five patients were entered into the study. Only data from those patients with stone presence confirmed by IV pyelogram or stone passage were analyzed. Twenty-four could not be evaluated (23 who did not meet criteria for stone presence and one whose pain resolved spontaneously before study medications could be administered). Of the remaining 51 patients, 31 received indomethacin first and 20 received morphine first. Morphine recipients reported more pain relief at ten minutes (P = .02), but at 20 and 30 minutes, no significant difference (P = .17 and .74, respectively) existed between the two groups.

CONCLUSION

IV morphine produced more rapid analgesia than rectally administered indomethacin. There were no significant differences in vital sign changes or number of side effects between the two treatment groups. This study is the first to compare an NSAID with morphine administered by IV titration, considered by many to be the "gold standard" for relief of acute, severe pain. Future studies could evaluate the simultaneous administration of an opioid combined with an NSAID or compare an IV titrated opioid with an IV NSAID.

Percutaneous transilial access for stone removal in crossed fused renal ectopia

A case of crossed fused renal ectopia with urosepsis due to multiple struvite calculi in the left lower pole of the orthotopic renal unit is presented. The patient had a neurogenic bladder secondary to myelodysplasia, bilateral ureteral reflux, and had undergone multiple orthopedic operations previously, including posterior iliopsoas transplantation through the iliac bone (Sharrard procedure). After controlling the infection, nephrostolithotomy was performed. Three percutaneous accesses including one through the opening in the left iliac bone were required to gain access to all the stones. The patient was rendered stone free and subsequently underwent bladder augmentation and ureteral reimplantation. The management of complicated renal units is reviewed with respect to crossed renal fusion.

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.

Stone surface area determination techniques: a unifying concept of staghorn stone burden assessment

The use of stone surface area measurements obtained from standard radiographs provides a more accurate and reproducible assessment of stone burden when reporting results and treatment recommendations for staghorn calculi. Techniques for determining stone surface area include use of graph paper, planimeter or computerized image analysis. The use of graph paper is inefficient while planimeters suffer from significant variation for areas less than 500 mm.2 (more than 5%). Computer image analysis is accurate, rapid and easiest to perform. Software programs compatible with microcomputers are readily available making assessment of stone surface area practical and inexpensive. Stone surface area showed close correlation to stone volume as measured by 3-dimensional computerized tomography (correlation coefficient 0.84, p = 0.005). Stone surface area determination enables more accurate reporting of treatment results and, thus, recommendations based upon stone burden. Comparison of data between institutions becomes more meaningful if stone surface area is used. Stone surface area also provides a useful basis to study and compare trends of treatment within a single institution.

Staghorn calculi: analysis of treatment results between initial percutaneous nephrostolithotomy and extracorporeal shock wave lithotripsy monotherapy with reference to surface area

Treatment recommendations and results reported for the management of staghorn calculi are highly variable. In an attempt to provide a more objective means to compare treatment results for staghorn renal calculi, stone burden as measured by stone surface area was used. Stone surface area was determined by computer analysis. A total of 380 cases of staghorn calculi treated at the same institution was evaluated. Treatment consisted of initial percutaneous nephrostolithotomy with or without extracorporeal shock wave lithotripsy (ESWL*) in 298 cases and ESWL monotherapy in 82. When considered as a group, the overall stone-free rate for initial percutaneous nephrostolithotomy (mean surface area 1,378.3 mm.2) was 84.2% compared to 51.2% (p less than 0.0001) for ESWL monotherapy (mean surface area 693.4 mm.2). For staghorn calculi smaller than 500 mm.2 a stone-free rate of 94.4% was achieved in the percutaneous nephrostolithotomy with or without ESWL group compared to 63.2% for ESWL monotherapy (p = 0.0214). For calculi of 501 to 1,000 mm.2 the stone-free rates were 86% and 45.7%, respectively (p less than 0.0001). When stone surface area exceeded 1,000 mm.2 the stone-free rate for percutaneous nephrostolithotomy with or without ESWL was 82.4% but it was only 22.2% for ESWL monotherapy (p = 0.0002). Overall, when adjusted for stone surface area the odds of being stone-free were more than 8 times higher for initial percutaneous nephrostolithotomy versus ESWL monotherapy (odds ratio = 8.36, p less than 0.0001). While percutaneous nephrostolithotomy with or without ESWL appears to be the procedure of choice for most staghorn stones, ESWL monotherapy may have a role for some stones smaller than 500 mm.2. In 12 such cases associated with a nondilated renal collecting system (mean surface area 380.5 mm.2) a stone-free rate of 91.7% was achieved. The number of procedures required to complete therapy was higher in the initial percutaneous nephrostolithotomy group (2.8 versus 2.1, p less than 0.0001). Although complications were more common in the ESWL monotherapy group (manifested as obstruction in 30.5%), bleeding requiring blood transfusion was more frequent in the initial percutaneous nephrostolithotomy group (9.4%).

New alternatives in gallstone treatment

Within the past few years, a number of new treatment modalities for gallbladder stones have become available. Laparoscopic cholecystectomy has proved as safe as traditional surgical cholecystectomy, without the discomfort and lengthy recuperation associated with a large abdominal incision. Several other new treatments also have been investigated, including percutaneous cholecystolithotomy, peroral drug chemolysis, extracorporeal shock wave lithotripsy, and methyl-tert-butyl ether lavage. The relative merits and disadvantages of these treatments, compared to each other and to standard cholecystectomy, are described herein.