John R. Woods

Extracorporeal Shock Wave Lithotripsy: The Methodist Hospital of Indiana Experience

A total of 982 patients underwent 1,416 treatments with extracorporeal shock wave lithotripsy for upper urinary tract calculi between February 23 and December 17, 1984. A single treatment was performed in 90 per cent of the patients. Morbidity was extremely low and hospital stay was short (3.0 days). Adjunctive procedures were required in 13 per cent of the patients. Of the kidneys 72 per cent were free of stones at the 3-month followup, while 23 per cent contained small (less than 5 mm.), asymptomatic fragments believed to be passable spontaneously. Only 1 per cent of the patients required surgical removal of the calculi. Morbidity was related directly to stone burden, while results were inversely related to stone burden. Extracorporeal shock wave lithotripsy is the preferred form of management for symptomatic upper ureteral and renal calculi less than 2 cm. in diameter.

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.

Comparison of Results and Morbidity of Percutaneous Nephrostolithotomy and Extracorporeal Shock Wave Lithotripsy

Two new therapies, percutaneous nephrostolithotomy and extracorporeal shock wave lithotripsy, are revolutionizing the treatment of upper urinary tract calculi. We report the success and morbidity rates in 110 patients undergoing percutaneous nephrostolithotomy and 982 patients treated with extracorporeal shock wave lithotripsy. Staghorn calculi were excluded from this series. The over-all success rate (free of stones plus small asymptomatic residual fragments) was comparable with both modalities (percutaneous nephrostolithotomy 98 per cent and extracorporeal shock wave lithotripsy 95 per cent), although the presence of residual fragments was more common in kidneys treated with extracorporeal shock wave lithotripsy (24 versus 7 per cent). Patient morbidity as measured by temperature elevation, length of postoperative stay, pain and blood loss was significantly less (p less than 0.05) with extracorporeal shock wave lithotripsy than with percutaneous nephrostolithotomy. Re-treatment rates were similar with both procedures, and tended to increase in relation to increasing stone size and stone number. Post-treatment ancillary procedures (cystoscopy and stone manipulation, and percutaneous nephrostomy) were used more frequently with extracorporeal shock wave lithotripsy. Because of its efficacy and low morbidity, we conclude that extracorporeal shock wave lithotripsy is the treatment of choice for upper urinary tract calculi less than 2 cm. in diameter. However, percutaneous nephrostolithotomy will continue to have a primary role in the management of larger stones and cystine stones, and it will be used as a secondary procedure after unsuccessful extracorporeal shock wave lithotripsy treatments. In addition, because of the complimentary nature of these 2 new technologies certain complex stones, such as staghorn calculi, may be handled best by a combination of the 2 techniques.

Management of upper ureteral calculi with extracorporeal shock wave lithotripsy.

The results of 471 extracorporeal shock wave lithotripsy treatments in 465 patients with solitary ureteral stones managed by several different techniques are reported. In situ treatment was performed in 123 cases without instrumentation and in 47 after placement of a ureteral catheter. Retrograde stone manipulation was performed in 245 cases immediately before extracorporeal shock wave lithotripsy and an additional 56 were manipulated with ureteral stent placement at least 1 week before extracorporeal shock wave lithotripsy. The success rate was significantly greater if the stone was manipulated into the kidney before extracorporeal shock wave lithotripsy. Significantly less energy (p less than 0.0001) was required for complete disintegration if the stone was free floating in the kidney. The need for subsequent procedures was significantly less (p less than 0.0001) for stones manipulated successfully into the kidney. Complications were infrequent, with the most common being ureteral perforation in 5.1 per cent of the cases, all of which were managed conservatively. Extracorporeal shock wave lithotripsy is the treatment of choice for proximal ureteral calculi because it is less morbid than percutaneous approaches and provides significantly better results than ureteroscopy. An attempt at manipulation of proximal ureteral calculi back into the kidney should be made before extracorporeal shock wave lithotripsy.

The role of lithotripsy and its side effects

The relative roles of extracorporeal shock wave lithotripsy and percutaneous nephrostolithotomy currently are being debated. Both treatment modalities are applicable to most upper urinary tract calculi. However, there are some important distinctions between the 2 techniques. Over-all, extra-corporeal shock wave lithotripsy is associated with significantly lower morbidity than percutaneous nephrostolithotomy but stone-free rates are lower for extracorporeal shock wave lithotripsy than for percutaneous nephrostolithotomy. This difference is slight for kidneys containing minimal stone burden but increases in direct proportion to increasing stone burden. The morbidity of extracorporeal shock wave lithotripsy also increases with increasing stone burden. When applied to the treatment of staghorn calculi the morbidity of both techniques is comparable but the stone-free rates are significantly better with percutaneous nephrostolithotomy. Treatment with extracorporeal shock wave lithotripsy produces changes in the kidney similar to that of renal trauma, consisting primarily of intraparenchymal and perirenal hemorrhage and edema. While the acute effects of extracorporeal shock wave lithotripsy are well tolerated by most patients, the long-term sequela of this form of therapy is not well established. Potential long-term adverse effects reported include loss of renal function, hypertension and an increased rate of new stone occurrence. The effect of shock waves on renal parenchyma in experimental animals is dose-dependent (number of shock waves). Magnetic resonance imaging of patients treated with extracorporeal shock wave lithotripsy demonstrates morphological abnormalities in or around the kidney in 63 to 85 per cent of the cases (average number of shock waves 1,200). Despite these observations the safe limits of extracorporeal shock wave lithotripsy in humans have yet to be established. Further study regarding this issue and the potential long-term adverse effects of extracorporeal shock wave lithotripsy is needed urgently.

The Two-Period Crossover Design in Medical Research

The crossover design has enjoyed popularity with many clinical researchers, but has been criticized by biostatisticians. The central problem is the inability to derive an unbiased estimate of the treatment effect when differences occur because of the different sequences in which treatments are applied. This problem can be traced to a deficiency of the logic of the crossover arrangement itself. Factors that can invalidate the findings of a crossover trial include nonuniform pharmacologic and psychologic carry-over effects, failure to return patients to their baseline state before the crossover, nonuniform changes in the patients over time, and the use of time-dependent response measures. When these problems can be anticipated, a parallel-groups design should be used instead of a crossover trial.

Comparison of a New Pressurized Saline Canister Versus Syringe Irrigation for Laceration Cleansing in the Emergency Department

STUDY OBJECTIVE Studies have documented the efficacy of normal saline irrigation in decreasing wound infection rates. Wounds traditionally are irrigated using a syringe and needle with manual injection of fluid, a time- and labor-intensive method. We compared irrigation times and infection rates for wounds cleansed with syringe irrigation versus a new, single-use canister of pressurized (8 psi) sterile normal saline. DESIGN Prospective, randomized, controlled. SETTING Two Level I emergency departments in tertiary care hospitals, both with emergency medicine residency programs. PARTICIPANTS Patients with lacerations requiring closure were eligible. Exclusion criteria were wounds above the clavicle more than ten hours old, wounds below the clavicle more than six hours old, insulin-dependent diabetes mellitus, or antibiotic or steroid therapy. Patients (550) were entered between August 1, 1990, and January 31, 1991. Characteristics of the two treatment groups were similar for patient age, age of the wound, size and depth of the laceration, and number of sutures. INTERVENTIONS Lacerations were irrigated with 250 mL saline in a syringe or 220 mL saline in a pressurized canister for each 5 cm of laceration. At follow-up or suture removal, patients were evaluated for signs of wound complications (cellulitis, ascending lymphangitis, purulent discharge, or dehiscence). MAIN RESULTS The mean irrigation time for the pressurized canister group (281) was 3.9 minutes versus 7.3 minutes in the syringe irrigation group (254) (P < .0001). The complication rate for the pressurized canister group was 5.0% compared with 3.6% for the syringe irrigation group (not significant, P = .50). Only three of the 20 total complications required antibiotics (two in the pressurized canister group, one in the syringe irrigation group). CONCLUSION Syringe irrigation times were nearly twice as long as the pressurized canister irrigation times. Use of the pressurized canister facilitates ease of irrigation and markedly decreases the time involved in this traditionally labor-intensive activity. In addition, delivery of the saline is no longer operator dependent, ensuring generation of pressures appropriate for wound cleansing. The pressurized canisters may be useful in standardizing irrigation in wound management research.

Financial analysis of an inner-city helicopter service: Charges versus collections

Trauma centers are now being perceived as financial burdens because of recent changes in trauma reimbursement for the Medicare Prospective Payment System population and the perception that collection rates are lower among trauma patients. We examined the demographic and clinical factors associated with the collection experience in a series of 114 trauma patients transferred by helicopter from the accident site to an inner-city trauma center. Factors affecting payment at 30, 60, 90, and 180 days included patient age, insurance class, and discharge status. While not as high as the collection rate for the facility as a whole, we found an average 71.2% collection rate for trauma patients at 180 days. As long as trauma reimbursement continues to be cost based for nonMedicare patients, collection rates remain an important consideration in determining the financial viability of trauma centers.

Continuously-infused human C-reactive protein is neither proatherosclerotic nor proinflammatory in apolipoprotein E-deficient mice.

Studies of human native C-reactive protein (nCRP) in mice have shown effects ranging from proatherogenic, to antiatherogenic, to no effect. It is likely that these disparities are related to (a) the use, in some studies, of contaminated nCRP, or to (b) variation in CRP levels associated with either its episodic administration or the use of CRP-transgenic mice. In our study, 12-week-old male apolipoprotein E–deficient (apoE −/−) mice, maintained on a Western diet, received azide- and endotoxin-free nCRP (n = 23) or placebo (n = 23) continuously via osmotic pumps (20.4 μg/day) for 4 weeks. CRP-treated and control mice developed similar atherosclerotic lesions in whole aortas (nCRP: 10.4 ± 4.7% vs. controls: 11.7 ± 4.4%, P = 0.76) and aortic roots (nCRP: 65.0 ± 7.8% vs. controls: 64.7 ± 9.7%, P = 0.94). No differences were observed in macrophage or T-lymphocyte infiltrates and there was no meaningful change in VCAM-1 or IL-6 expression, in the levels of soluble VCAM-1, or in circulating proinflammatory (IL-1β, IL-6, IL-12p40, IL-12p70, TNF-α, and INF-γ), or anti-inflammatory (IL-4 and IL-10) cytokines. We conclude that continuous infusion of uncontaminated nCRP in apoE −/− mice is not associated with increased atherosclerosis, does not alter systemic or local inflammation, and does not affect endothelial activation. These observations suggest that alternative approaches to study CRP (perhaps using different pentraxins in the mouse model or using a rabbit model instead of a mouse model) are needed to evaluate the effects of pentraxins on atherosclerosis.

An analysis of reimbursement for outpatient medical care in an urban hospital emergency department

The investigators examined the demographic and clinical factors associated with the collection experience in a series of 786 patients who were treated in an urban hospital emergency department (ED) but not admitted to the hospital. They found that 57% of the total net charge of