A S Cass

Hennepin County Medical Center, Minneapolis, Minnesota, United States

Are you A S Cass?

Claim your profile

Publications (97)242.66 Total impact

  • Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: A controversy has arisen as to whether the initial form of therapy for lower pole nephrolithiasis should be extracorporeal shockwave lithotripsy (SWL) or percutaneous nephrolithotomy (PCNL). We reviewed our results with 968 single lower pole stones treated by SWL and reviewed publications comparing SWL and PCNL for lower pole nephrolithiasis. In our cases, the stone-free rate was 71.2%, the rate of repeat treatment and post-treatment secondary procedures was 6.4%, the complication rate was 0.5%, and the hospital stay was less than 24 hours in 99.3% of patients. In published series of PCNL for lower pole nephrolithiasis, the stone free rate was 70.5% to 100%, repeat treatment rates were 4% to 62.5%, the complication rates were 13% to 38%, and the hospital stay was 3.1 to 6.1 days. The rates of recurrent stone disease with PCNL were 11% to 22%, similar to the rates after SWL. The percentage of renal urolithiasis patients with lower pole calculi since we started our unit in late 1986 has remained essentially constant at 38%. Although the stone-free rate with PCNL is higher than with SWL, the lower complication rate, lower repeat treatment/secondary procedure rate, the shorter hospital stay, and the similar recurrent stone rate with SWL make SWL more clinically effective as the primary therapy for lower pole calculi less than 2 cm in diameter.
    Journal of Endourology 03/1996; 10(1):17-20. DOI:10.1089/end.1996.10.17 · 2.10 Impact Factor
  • Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: Some reports have shown a decreased effectiveness of extracorporeal shock wave lithotripsy (ESWL*) with newer lithotriptors. We used a first generation unmodified Dornier HM3 lithotriptor to treat 5,698 patients with renal and ureteral calculi and a second generation Medstone STS device to treat 8,166 patients with renal and ureteral calculi. The treatment results were compared using the chi-square test to determine statistical significance. The stone-free rate, retreatment rate and post-ESWL secondary procedure rate were 69.5%, 4.4% and 3.1%, respectively, with the Dornier HM3 device and 72.1%, 4.9% and 2.3%, respectively, with the Medstone lithotriptor for single renal stones, and 81.5%, 5.2% and 5.5%, respectively, with the Dornier HM3 and 83.2%, 5.2% and 5.0%, respectively, with the Medstone device for single ureteral stones. There were no statistically significant different results between a second generation tubless Medstone STS lithotriptor and the gold standard unmodified Dornier HM3 instrument.
    The Journal of Urology 04/1995; 153(3 Pt 1):588-92. DOI:10.1097/00005392-199503000-00006 · 3.75 Impact Factor
  • Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: We studied renal function an average of 44 months after simultaneous bilateral renal SWL in 56 patients. No cases of clinically apparent acute renal failure occurred in the early postoperative period. The glomerular filtration rate (GFR) was calculated using an empiric formula having a significant correlation with measured creatinine clearance, and a change of 20% or greater was considered a clinically significant deterioration in renal function. Of the seven patients with a preoperative serum creatinine concentration of > 1.5 mg/dL, six had an average increase of 35% in postoperative GFR attributable to relief of obstruction, while one had a 30% reduction in GFR. Among 49 patients with a preoperative serum creatinine concentration of 1.5 mg/dL or less, there was an increase in postoperative GFR in 22 patients (45%), no change in 3 (6%), and a decrease in 24 (49%), who had a higher number of multiple renal stones (p < 0.05) and of repeat SWL (p = 0.08). Nine of them (18%) had a clinically significant decrease in GFR of > 20%. A review of the literature showed a long-term reduction of function in the individual human kidney after SWL in some cases of a solitary kidney and in some cases with an untreated contralateral kidney. Because there is no evidence that an untreated contralateral kidney aids the long-term recovery of the function of a treated kidney in all cases, simultaneous or separate bilateral renal SWL would not influence this long-term reduction in renal function, which was felt to occur with multiple renal stones and repeat SWL.
    Journal of Endourology 01/1995; 8(6):395-9. DOI:10.1089/end.1994.8.395 · 2.10 Impact Factor
  • Alexander S. Cass, John E. Heller
    [Show abstract] [Hide abstract]
    ABSTRACT: When pull on a stone basket enclosing a distal ureteral stone met marked resistance and endoscopic lithotripsy failed, extracorporeal shock wave lithotripsy was used to fragment the entrapped stone in the ureter and allowed successful removal of the basket with the enclosed fragments.
    Urology 05/1994; 43(4):544-5. DOI:10.1016/0090-4295(94)90253-4 · 2.13 Impact Factor
  • Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine if a ureteral stent or catheter was necessary to achieve satisfactory results with extracorporeal shock-wave lithotripsy (ESWL) for a stone in the ureter. A retrospective review of 1,712 single ureteral stones treated in the ureter by ESWL using Dornier HM3 and Medstone STS lithotriptors was performed, 1,425 with a stent and 287 without a stent (in situ). Statistical analysis was performed using the chi-square test to determine the p value. The stone site, size, and treatment parameters (average shocks, kV, and estimated radiation to the patient) were similar in both groups. The retreatment rate, post-ESWL secondary procedure rate, and stone-free rate were 5 percent, 5 percent, and 79 percent, respectively, with a stent and 6 percent, 9 percent, and 79 percent, respectively, without a stent. The results of ESWL for single ureteral stones were similar with or without a stent, making the presence of a ureteral stent unnecessary.
    Urology 03/1994; 43(2):178-81. DOI:10.1016/0090-4295(94)90040-X · 2.13 Impact Factor
  • Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: Studying renal function in patients with a solitary kidney undergoing SWL eliminates the compensatory effects of an untreated contralateral kidney and thus indicates any loss of function in the treated kidney. In 17 patients with a preoperative serum creatinine clearance of 1.5 mg/dl or less who underwent SWL to a solitary kidney, the glomerular filtration rate (GFR) was calculated by the formula of Cockcroft and Gault, which correlates significantly with measured creatinine clearance. A change of > or = 20% in the GFR was considered a clinically significant deterioration of renal function. In 12 patients with < 24 months' follow-up (mean 7.3 months) after SWL, there was no change in the estimated GFR, whereas 5 patients with > 24 months' follow-up (mean 36 months) had an average 22% reduction in the estimated GFR. This long-term effect is similar to the 29% long-term reduction in renal function recorded after percutaneous nephrolithotomy in solitary kidneys. Multiple stones, higher numbers of shock waves, and repeated SWL sessions correlated with decreases in GFR, but none of the differences was statistically significant. Like percutaneous nephrolithotomy, SWL results in a clinically significant long-term reduction in renal function.
    Journal of Endourology 02/1994; 8(1):15-9. DOI:10.1089/end.1994.8.15 · 2.10 Impact Factor
  • Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: To compare the results of using Dornier HM3 and Medstone STS lithotriptors to treat a ureteral stone overlying the pelvic bone (mid third of ureter) requiring the patient to be in the prone position. The ease of use with each lithotriptor was evaluated and a retrospective review of the results using a Dornier HM3 in 53 patients and a Medstone STS in 143 patients was performed. The chi-square test was used to determine statistical difference. With single stones, the re-treatment rate, the post-ESWL secondary procedure rate, and the stone-free rate were 6 percent, 13 percent, and 75 percent, respectively, with the Dornier, and 6 percent, 8 percent, and 80 percent, respectively, with the Medstone. There was no statistically significant difference between these outcome results (p > 0.05). The prone position was difficult to achieve with the Dornier HM3, while the Medstone STS, a tubeless lithotriptor, allowed easy positioning of the patient in the prone position on its flat table. Satisfactory results were achieved using either machine.
    Urology 02/1994; 43(2):182-5; discussion 185-6. DOI:10.1016/0090-4295(94)90041-8 · 2.13 Impact Factor
  • Alexander S. Cass, Joe Y. Lee, Carl S. Smith
    [Show abstract] [Hide abstract]
    ABSTRACT: Perirenal extravasation of urine with an intact renal parenchyma and with dye visualized in the ureter was seen on an excretory urogram (IVP) and computed tomographic (CT) scan in two patients (bilateral in one) with multiple injuries following blunt trauma. Expectant management with no invasive procedures resulted in disappearance of the extravasation within 3 to 5 days. Traumatic rupture of a calyceal fornix is thought to be the cause of the extravasation similar to the perirenal extravasation seen with renal colic from a ureteral calculus.
    The Journal of trauma 08/1993; 35(1):20-2. DOI:10.1097/00005373-199307000-00003 · 2.96 Impact Factor
  • Joe Y. Lee, Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: One of the most important advances in trauma to the lower urinary and genital tracts has been the increased use of imaging techniques in its diagnosis and treatment. Computed tomography has been used in the diagnosis of bladder rupture and magnetic resonance imaging and ultrasonography in the diagnosis of post-traumatic urethral strictures. The treatment of post-traumatic urethral strictures by endoscopic urethroplasty has been facilitated by ultrasonography and fluoroscopy and ultrasonography has helped with blunt testicular injury in deciding surgery or observation. (C) Lippincott-Raven Publishers.
    Current Opinion in Urology 05/1993; 3(3). · 2.12 Impact Factor
  • Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: A case report of an acute severe genital infection simulating Fournier's gangrene was subsequently found to be caused by chickenpox.
    Urology 02/1993; 41(1):52-3. DOI:10.1016/0090-4295(93)90245-6 · 2.13 Impact Factor
  • ALEXANDER S. CASS
    [Show abstract] [Hide abstract]
    ABSTRACT: Concerns have been expressed by some in the United States that extracorporeal shock wave lithotripsy (SWL) for mid and lower ureteral stones could damage ovarian reproductive function, is difficult to perform with a Dornier HM3, and is not as effective as ureteroscopy. Seventy-nine patients with midureteral stones and 45 patients with lower ureteral stones were treated using Dornier HM3 and Medstone STS lithotripters. With the latter machine, the head and foot angle radiographs, the absence of the water-filled tub, and the easy prone positioning of the patient made the visualization and treatment of the mid and lower ureteral stones easier to perform. With single stones, the stone-free rate at 3 months was 77%, the retreatment rate was 2%, and the post-SWL secondary procedure rate was 15%. However, stone retrieval by ureteroscopy in the lower third of the ureter is a single procedure without the need for secondary or repeat treatments and, with reported stone-free rates of 83% to 93%, it is more efficient and less expensive than ESWL.
    Journal of Endourology 10/1992; 6(5):323-326. DOI:10.1089/end.1992.6.323 · 2.10 Impact Factor
  • ALEXANDER S. CASS
    [Show abstract] [Hide abstract]
    ABSTRACT: De novo extracorporeal shock wave lithotripsy (SWL) for ureteral stones is appealing because no instrumentation is used and stone-free rates of 90%+ are reported with low-power lithotripters using minimal or no anesthesia. This makes SWL an attractive alternative to ureteroscopic stone extraction and to ureteral stent/SWL, which give similar stone-free rates but require instrumentation and major anesthesia. De novo SWL using high-power lithotripters (Dornier HM3 and Mestone STS) and general anesthesia was used on 100 patients with impacted ureteral stones of 2 weeks' duration or longer (upper ureter 80, mid 6, lower 14). There were 78 single stones and 22 multiple stones. The retreatment and post-SWL secondary procedure rates with single stones were 6% and 14%, respectively, and with multiple stones were 9% and 18%, respectively. The stone-free rate at 3 months was 78% with single stones and 73% with multiple stones. The difference in stone-free rates between low- and high-power lithotripters performing de novo SWL for ureteral stones is difficult to explain except for the theory that low-power machines fragment stones into smaller particles that are more readily passed down the ureter or the fact that low-power lithotripters are used by some urologists for the immediate treatment of acute renal colic caused by small ureteral stones that would have passed spontaneously with a short period of observation.
    Journal of Endourology 10/1992; 6(5):315-318. DOI:10.1089/end.1992.6.315 · 2.10 Impact Factor
  • Alexander S. Cass
    [Show abstract] [Hide abstract]
    ABSTRACT: We reviewed the results of ureteral stent use with extracorporeal shock-wave lithotripsy (ESWL) in 3,096 patients with renal calculi less than 3 cm in diameter. The 2,595 patients with indwelling ureteral stents required lower total power (shocks x voltage) and less radiation and had a lower secondary procedure rate but a higher retreatment rate than the 501 patients without stents. However, the only statistically significant difference was in the average radiation dose in patients with or without stents and single stones no larger than 10 mm (16 vs. 18 rad). The hospital stay was one day or less in 98 percent of the patients in both groups. With an 80 percent follow-up rate at three months indwelling ureteral stents were associated with a higher stone-free rate in patients with a single stone but a lower stone-free rate in patients with multiple stones, compared with those treated without a stent. An indwelling ureteral stent may result in urinary frequency and bladder discomfort in some patients, and with no statistical difference in the results with or without a ureteral stent it is questionable whether or not the high use of an indwelling ureteral stent is justified in patients admitted for one day or less.
    Urology 06/1992; 39(5):446-8. DOI:10.1016/0090-4295(92)90244-Q · 2.13 Impact Factor
  • Alexander S. Cass, Michael Luxenberg
    [Show abstract] [Hide abstract]
    ABSTRACT: We reviewed 91 testicular injuries in 86 patients (5 bilateral) as a result of blunt trauma in 72 patients and gunshot wounds in 14 patients. In 90 percent of the patients the injury was solitary. With blunt trauma initially conservative management led to the loss of the entire testis in 21 percent in comparison with only 6 percent of those explored promptly. The recent use of testicular ultrasonography has not differentiated intratesticular hematoma from rupture in the majority of cases of blunt trauma. Bilateral testicular injury occurred in 1 of 72 patients (1.4%) with blunt trauma versus 4 of 14 (29%) with penetrating trauma and affected the fertility in 3 of 4 patients on follow-up.
    Urology 07/1991; 37(6):528-30. DOI:10.1016/0090-4295(91)80317-Z · 2.13 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In 6 patients who underwent ultrasound scanning and operation after blunt testicular trauma, the scan suggested the correct diagnosis in only 2 patients. There was one false-positive and three false-negative diagnoses of rupture. Absence of firm diagnostic criteria for rupture and high error rates with various criteria now in use make reliance on ultrasound in the diagnosis of testicular rupture inappropriate at this time.
    Urology 10/1990; 36(3):253-4. DOI:10.1016/0090-4295(90)80267-Q · 2.13 Impact Factor
  • A S Cass, M Luxenberg
    [Show abstract] [Hide abstract]
    ABSTRACT: We found simultaneous upper and lower urinary tract injury to be rare, being present in 10 of 2,310 patients (0.4%). Multiple associated injuries were present in all patients (average 4.4 per patient). In 3 patients both upper and lower urinary tract injuries were minor, and 1 patient died of associated injuries. In 4 patients one of the urinary injuries was significant and the other minor, and 2 of these patients died. In 3 patients both urinary injuries were significant, and all 3 died of associated injuries. A comprehensive urologic evaluation was required in all 10 patients because of their severe associated multiple injuries.
    Urology 10/1990; 36(3):226-7. DOI:10.1016/0090-4295(90)80260-T · 2.13 Impact Factor
  • A S Cass, Michael Luxenberg
    [Show abstract] [Hide abstract]
    ABSTRACT: The accuracy of computed tomography (CT) in the diagnosis of renal artery injury has not been resolved. Since 1982, 428 patients with renal trauma have been evaluated at our institutions, 35 of whom were suspected of having a severe renal injury by clinical examination and initial urography and were managed by repeated clinical observation and CT scans. Seven of these patients had main or branch renal artery injuries, all of which were diagnosed with CT by the absence of opacification or lack of enhancement of the kidney or a renal segment and confirmed by arteriography, surgery, or follow-up radiologic studies. In our experience, CT was accurate in the diagnosis of renal artery injury.
    Urology 12/1989; 34(5):249-51. DOI:10.1016/0090-4295(89)90318-X · 2.13 Impact Factor
  • A S Cass, M Luxenberg
    [Show abstract] [Hide abstract]
    ABSTRACT: If there was a correlation between the type of renal laceration and its healing, and if radiologic evaluation on admission could accurately diagnose the type of renal laceration present, then surgical intervention could be reserved for those renal lacerations that will not heal satisfactorily by themselves. We reviewed the outcome of initially conservative or immediate operative treatment of renal laceration in 122 patients. Thirty-six patients were managed initially without operation. All fifteen cortical lacerations and all five deep lacerations that created only a small parenchymal defect healed themselves, with 4 of the 16 patients available for follow-up having hypertension. In contrast, six deep lacerations that caused large parenchymal defects, six disrupted poles or segments, and four split kidneys did not have satisfactory healing with conservative management, necessitating delayed renal surgery, or causing hypertension or both. Because computed tomography on admission can accurately diagnose the site and extent of a renal laceration, it should be possible to decide early which patients truly will benefit from conservative management.
    Urology 06/1989; 33(5):367-70. DOI:10.1016/0090-4295(89)90027-7 · 2.13 Impact Factor
  • A S Cass, Michael Luxenberg
    [Show abstract] [Hide abstract]
    ABSTRACT: We reviewed 105 cases of extraperitoneal bladder rupture admitted to our hospitals from 1959 to 1985. Primary suturing of the rupture was performed in 65 patients, and catheter drainage alone without suturing of the rupture was performed in 34. The incidence of blunt trauma causing the rupture of gross hematuria on admission, and of associated injuries was similar in both groups. There was a higher incidence of women older than sixty years in the group managed by catheter drainage alone, and a higher incidence of laparotomy for associated intra-abdominal injuries and a higher mortality rate in the group treated by primary suturing. There were three early complications in the group treated by suturing (hematuria with clot retention 2, sepsis contributing to death 1) and four early complications in the conservatively treated group (hematuria with clot retention 1, pseudodiverticulum with bone spike in its floor 1, persistent urinary fistula 1, and sepsis contributing to death 1). There were two late complications in 42 patients followed in the group treated by suturing (urethral stricture 1, frequency and dysuria 1), and three late complications in 14 patients followed in the conservatively treated group (hyperreflexic bladder 2, urethral stricture and vesical calculi 1). Catheter drainage alone for extraperitoneal rupture from external trauma was simple, quick to perform, and appealing in the multiple-injured patient. Although the early and late complication rates were higher in the conservatively managed group, there was no statistically significant difference from the group treated by primary suturing.
    Urology 04/1989; 33(3):179-83. DOI:10.1016/0090-4295(89)90386-5 · 2.13 Impact Factor
  • R Gary, A S Cass, G Koos
    [Show abstract] [Hide abstract]
    ABSTRACT: Retrograde or antegrade transurethral incision of urethral strictures that have formed after complete rupture of the membranous urethra has been advocated to restore urethral continuity. With this technique we encountered vascular complications in 2 patients, which consisted of opening of a patent vessel entrapped in the fibrous tissue of the stricture. The opened vein in 1 patient healed without bleeding. The opened artery in the other patient did not heal with catheter drainage and pressure dressings, resulting in recurrent severe hemorrhage that necessitated stage 1 urethroplasty with ligation of the artery. The entrapment of a patent vessel in fibrous scar tissue resulting from complete urethral rupture is believed to be responsible for these complications.
    The Journal of Urology 01/1989; 140(6):1539-40. · 3.75 Impact Factor

Publication Stats

1k Citations
242.66 Total Impact Points

Institutions

  • 1978–1996
    • Hennepin County Medical Center
      Minneapolis, Minnesota, United States
  • 1994
    • Abbott Northwestern Hospital
      Minneapolis, Minnesota, United States
  • 1976–1989
    • St. Joseph's Hospital, St. Paul, Minnesota
      Minneapolis, Minnesota, United States
  • 1976–1985
    • Gillette Children's Specialty Healthcare
      Saint Paul, Minnesota, United States