S S Carter

Hannover Medical School, Hanover, Lower Saxony, Germany

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Publications (11)28.08 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The objective of the study was to investigate specificity and sensitivity of bladder wall thickness in the diagnosis of bladder outlet obstruction. The study included 174 patients referred to our prostate centers for lower urinary tract symptoms. Free uroflowmetry and pressure-flow studies were performed in duplicate as part of the diagnostic evaluation. After the 2 voiding studies were done the bladder was filled to 150 ml. and wall thickness was measured via suprapubic ultrasound. Bladder outlet obstruction was diagnosed and graded according to the Abrams-Griffiths and Schäfer nomogram as well as to the group specific urethral resistance algorithm. A significant correlation (r > 0.6, p < or = 0.007) was found between bladder wall thickness and all parameters of the pressure-flow study. A bladder wall thickness of 5 mm. appeared to be the best cutoff point to diagnose bladder outlet obstruction, since 63.3% of patients with bladder wall thickness less than 5 mm. were unobstructed while 87.5% of those with a bladder wall thickness 5 mm. or greater were obstructed. Bladder wall thickness out performed uroflowmetry in terms of specificity and sensitivity in the diagnosis of outlet obstruction as demonstrated by an area under curve value of 0.860 versus 0.688 in the receiver operator characteristics analysis. Measurement of bladder wall thickness appears to be a useful predictor of outlet obstruction with a diagnostic value exceeding free uroflowmetry although it does not represent a substitution to invasive urodynamics. These data support the hypothesis that the relationships between morphology and function are of clinical importance.
    The Journal of Urology 03/1998; 159(3):761-5. · 3.75 Impact Factor
  • R M Walker, A Patel, S St Clair Carter
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    ABSTRACT: To determine the effect of urethral instrumentation on pressure-flow study values and subsequent grading of bladder outflow obstruction (BOO) in men with lower urinary tract symptoms (LUTS) using suprapubic intravesical pressure monitoring. Seventy-two men with LUTS underwent pressure-flow study using suprapubic intravesical pressure monitoring. The urethra was then instrumented successively with a 12 F catheter and a 17 F cystoscope, and a further pressure-flow study recorded after each procedure. Standard pressure-flow variables were measured for the three recordings. The presence and degree of obstruction were determined using commonly recognized grading systems, i.e. the Abrams-Griffiths nomogram. the linear passive urethral resistance ratio (LPURR) and the urethral resistance algorithm (URA). There were statistically significant differences in the detrusor pressure at maximum flow and detrusor opening pressure between the uninstrumented and instrumented studies (12 F and 17 F) but no difference in peak flow rates between the groups or in the Abrams-Griffiths number or URA value between studies. Using the LPURR, there was a tendency to a lower obstruction class after urethral instrumentation, ranking as 17 F > 12 F > no instrumentation. The changes seen after urethral instrumentation represent no more than the biological intra-individual variation normally seen in pressure-flow studies and do not lead to a clinically significant change in obstruction class.
    British Journal of Urology 02/1998; 81(2):206-10.
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    ABSTRACT: The urodynamic profiles of 97 patients with benign prostatic hyperplasia undergoing low-energy transurethral microwave thermotherapy (TUMT) for lower urinary tract symptoms were analysed using the Abrams/Griffiths nomogram, the urethral resistance algorithm, the linPURR, Schäfer nomogram, and the CHESS classification. A significant clinical response was seen for the whole group, as shown by changes in symptom score, free flow rate, and residual urine. The best symptomatic response was identified in patients in whom obstruction was present, whatever the classification used. Only the two-dimensional CHESS classification was found to predict a group of patients with a better response in both symptoms and objective variables. Obviously, a better response from TUMT can only be predicted by a classification system that identifies the independent variables of footpoint and slope of the PURR. The CHESS classification was the only one of those studied that satisfactorily identified these two parameters and could be used as a system of case selection for this minimally invasive treatment.
    Neurourology and Urodynamics 01/1998; 17(2):109-20. · 2.67 Impact Factor
  • R M Walker, B Di Pasquale, M Hubregtse, S St Clair Carter
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    ABSTRACT: To compare suprapubic and transurethral methods of measuring intravesical pressure in a group of men undergoing investigation for lower urinary tract symptoms (LUTS), to identify which urodynamic variables are affected by the presence of an urethral catheter during the voiding phase, and consequently whether there is any change in the grading of bladder outflow obstruction (BOO) using the commonly recognised grading systems. Thirty-five men with LUTS underwent both suprapubic and transurethral pressure-flow studies during a single session. Standard pressure flow variables were measured in all patients with both methods, enabling calculation of obstruction using the commonly used grading systems, i.e. the Abrams-Griffith number, linear passive urethral resistance ratio (LPURR) and urethral resistance algorithm (URA). There were statistically significant differences between the methods in the mean values of maximum flow rate and the detrusor pressure at that maximum: 60% of men were in the same LPURR class with either method. Using the transurethral method, 26% of patients increased the LPURR class by one and 6% by two classes. Using the Abrams-Griffiths nomogram, 17% moved from a classification of equivocal to obstructed and 3% from unobstructed to equivocal. Using the criterion of a value of URA > 29, 57% were obstructed using the suprapubic and 74% using the transurethral method. According to the method used, there were differences in the classification of obstruction between the suprapubic and transurethral routes; transurethral studies tended to indicate greater obstruction. The interpretation of urodynamic studies should take into account the technique used and where the route is transurethral, the smallest catheter available should be used.
    British Journal of Urology 05/1997; 79(5):693-7.
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    ABSTRACT: We compared manual versus computer analysis of pressure-flow tracings for diagnosing bladder outlet obstruction in patients with benign prostatic hyperplasia. A total of 105 patients with a clinical diagnosis of prostate enlargement and lower urinary tract symptoms was included in the study irrespective of free flow rates. Pressure-flow studies were performed in duplicate and tracings were evaluated by 2 independent investigators blinded to patients status. Manual reading of urodynamic printouts and fully computerized analysis using CLIM software were done. All urodynamic parameters relevant to the diagnosis of outlet obstruction were compared using the Abrams-Griffiths and Schäfer nomograms. Group specific urethral resistance factors were also compared. There was good correlation between manual and computer derived values of maximum flow (r = 0.9874, p < or = 0.0001), detrusor pressure at maximum flow (r = 0.9943, p < or = 0.0001), minimum detrusor pressure during voiding (r = 0.8816, p < or = 0.0001) and group specific urethral resistance factor (r = 0.9917, p < or = 0.0001). The diagnosis of outlet obstruction according to the group specific urethral resistance factor, and the Abrams-Griffiths and Schäfer nomograms was highly consistent using the manual and computerized approaches. Manual analysis of pressure-flow tracings generated by urodynamic equipment and digital data obtained by CLIM software appeared to be highly consistent and equally reliable for diagnosing and grading outlet obstruction.
    The Journal of Urology 04/1997; 157(3):871-5. · 3.75 Impact Factor
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    ABSTRACT: A retrospective study was done to investigate the long-term outcome of patients treated with lower energy transurethral microwave thermotherapy. A total of 305 patients with lower urinary tract symptoms and benign prostatic hypertrophy underwent transurethral microwave thermotherapy according to a similar protocol at 2 centers. After 3 years of followup 133 patients who had undergone transurethral microwave thermotherapy alone were available for study. During this observation period significant symptomatic improvement from baseline and an improved maximum flow rate of 2.6 ml. per second were noted. Of the patients 125 underwent invasive or medical treatment. After 3 years of followup lower energy transurethral microwave thermotherapy showed significant and durable improvements in baseline parameters in 52% of the patients.
    The Journal of Urology 01/1997; 156(6):1959-63. · 3.75 Impact Factor
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    ABSTRACT: We documented the results of high energy transurethral microwave thermotherapy in the treatment of benign prostatic hyperplasia. We evaluated 116 patients following transurethral microwave thermotherapy according to symptom scores, transrectal ultrasound, free voiding and pressure-flow study parameters. Significant improvement was noted in all objective and subjective parameters. Moreover, cavities in the prostatic urethra were observed in almost 40% of the patients. High energy transurethral microwave thermotherapy is an effective therapy for benign prostatic hyperplasia. Patients with larger prostates and moderate to severe bladder outlet obstruction seem to be the best candidates for this higher energy thermotherapy protocol, although morbidity is increased.
    The Journal of Urology 08/1996; 156(1):97-101; discussion 101-2. · 3.75 Impact Factor
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    ABSTRACT: To determine the placebo effect of transurethral microwave thermotherapy (TUMT) in the treatment of benign prostatic enlargement (BPE). A prospective, randomized sham-controlled study in 93 patients (mean age 65, range 50-88) was conducted at two centres comparing TUMT or a sham treatment. Patients randomized to receive sham treatment underwent the same initial procedure as for TUMT, but the complete procedure was simulated on the visual display with no application of microwave energy. If the patient's condition had not improved after 3 months, a second genuine TUMT treatment was given at the patient's request. After 3 months there were significant clinical and statistical differences in efficacy between the groups; 62% and 18% of patients had a > 50% improvement in symptom score in the treated and sham groups, respectively (P = 0.001). The corresponding changes in flow rate were 36% and 11% (P = 0.002), respectively. After 1 year, 63 patients were divided into those that had TUMT initially, those that had sham initially but subsequently had TUMT and those whose sham procedure had led to sufficient clinical improvement to require no further treatment. The two treated groups had a significant improvement over the sham group. The benefit from TUMT cannot be due to a placebo effect alone.
    British Journal of Urology 03/1996; 77(2):221-7.
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    ABSTRACT: We attempted to identify any parameter that could possibly lead to a successful treatment outcome after transurethral microwave thermotherapy. Clinical parameters and treatment profiles of 292 patients were analyzed in a retrospective multicenter manner. Responder and nonresponder groups were identified according to a given definition. No statistically significant differences in baseline characteristics were found. Responders showed a 76% symptomatic improvement rate compared to 27% in nonresponders, and an 82% improvement rate in peak flow compared to a 5% decrease in nonresponders. Responders also showed a significantly greater increase in posttreatment PSA level and a significantly greater amount of energy released during treatment. No baseline clinical parameter is capable of predicting treatment outcome.
    The Journal of Urology 12/1995; 154(5):1775-8. · 3.75 Impact Factor
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    ABSTRACT: We document changes in pressure-flow study parameters in patients treated by transurethral microwave thermotherapy. Pressure-flow study tracings before and after therapy from 75 patients with benign prostatic hyperplasia were analyzed. Patients were stratified according to the predominant type of obstruction at screening (constrictive or obstructive). An improvement in Madsen score and flow rates was noted at 6 months in both groups. In contrast to compressive obstruction patients, however, those with constrictive obstruction also showed significant changes in pressure-flow study parameters, including detrusor pressure at maximum flow, maximum flow rate and urethral resistance factor. Patients with predominantly constrictive obstruction are the best candidates for microwave thermotherapy.
    The Journal of Urology 11/1995; 154(4):1382-5. · 3.75 Impact Factor
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    ABSTRACT: The findings of improved clinical results in certain patient groups in some studies suggest that the full clinical benefit of TUMT has been under-reported. The objective must be to find the thermal dose, which will maintain a clinically significant reduction in symptoms with objective evidence of improved urinary flow and reduction in obstruction, while causing minimal post-treatment morbidity and still not necessitating anaesthesia. The maximum benefit of TUMT will be obtained only by selection of individual patients for specific therapeutic protocols.
    World Journal of Urology 02/1994; 12(6):352-6. · 2.89 Impact Factor

Publication Stats

301 Citations
28.08 Total Impact Points


  • 1998
    • Hannover Medical School
      Hanover, Lower Saxony, Germany
  • 1997
    • Sapienza University of Rome
      Roma, Latium, Italy
  • 1994
    • Radboud University Nijmegen
      • Department of Urology
      Nijmegen, Provincie Gelderland, Netherlands