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LETTERS TO T H E EDITOR RepLy by Authors. We would not combine endoureterotomy with intracorporeal lithotripsy for ureteral stones unless there was a previously proved ureteral stricture. It is not uncommon for edema or n ring-like constriction below a ureteral stone to resolve completely once the stone is removed, making ureterotomy unnecessary and perhaps meddlesome. The use of ureteral stents after ureteroscopy is interesting. The usual teaching is that if the ureteral orifice is balloon dilated to facilitate ureteroscopy, edema can occur thereafter creating obstruction and pain. With the advent of small mini-ureteroscopes combined with laser lithotripsy it is highly probable t h a t in many cases the requirement for a stent may be eliminated. We are currently conducting a randomized prospective trial of stent versus no stent for ureteroscopy patients not undergoing dilation of the ureteral orifice. When using the holmium:YAG laser endoscopically proper precautions must be taken to avoid not only ureteral wall injury but damage to endoscopic or other endourological equipment in proximity to the activated laser fiber. The fiber must extend 1to 2 mm. beyond the tip of the endoscope to avoid damage to the optics. Likewise, this powerful tool has the capability of cutting through guide wires or wire baskets. Such complications can be avoided with attention to technique and by taking advantage of the fact t h a t ho1mium:YAG laser energy is absorbed within 1 mm. water at the settings commonly used for laser lithotripsy.
RE: ALTERNATIVE APPROACHES TO THE PROGNOSTIC STRATIFICATION O F MILD TO MODERATE PRIMARY VESICOURETERAL REFLUX IN CHILDREN
R. Sciagru, M. Materassi, V. Rossi, R. Ienuso, A . Danti and G. LaCaua J. Urol., 155: 2052-2056, 1996
To the Editor. The authors suggest in this report that to perform technetium-dimercapto-succinic acid (DMSA) renal scans in all children with urinary tract infections and followup with voiding cystography only in those with scars would be cost-effective. Despite this conclusion, they include neither numerical support for their supposition nor figures for cost. In fact, the DMSA scan in most cases is 4 times t h e cost of a voiding cystourethrogram. If, indeed, the authors' premise is followed by performing DMSA scans on all children with urinary tract infections and then following those with upper tract changes with voiding cystourethrograms, the cost for the 105 children in this series would have been approximately $71,000. By doing the opposite, a s we currently practice, obtaining voiding cystourethrograms in all children with urinary tract infections and then DMSA scans in those with reflux or febrile illnesses, the cost would only be $51,720. The suggested approach not only is not cost-effective, but i t actually costs 40% more to evaluate this group of children. However, the greater concern of this approach is not the costeffectiveness but rather that 30%' of the children in this group with infections who have r e f l w will be overlooked. Even if disease is low grade, the authors clearly state t h a t a third of their children with low grade reflw, defined as grade 2, had renal scars. While the authors state t h a t they do not know the effect of missing this 30% with reflux, I believe the repeated urinary tract infections, propensity for renal scarring and ultimate need for evaluation would be deleterious. Additionally, from their data, if one is concerned with trying to predict persistent reflux, the presence of grade 3 reflux is virtually a s good as their combination of voiding cystourethrogram and DMSA scan (76% versus 84%). In the final analysis, the suggested approach by the authors will not alter the overall urological management of children with reflux and infections, and is probably more costly than cost-effective with no more predictive value for persistent reflux than simple r e f l u grading alone. Additionally, almost 30% of the children with reflux and infections a r e at risk for having the r e f l w missed. I t still seems
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prudent to tailor the management of a pediatric urinary tract infection to the clinical picture rather than to technical testing in which nonclinicians may have a vested interest. Respectfully,
H. Norman Noe Pediatric Urology University of Tennessee, Meniphis College of Medicine 770 Estate Memphis. Tennessee 38120 Reply by Authors. It is tricky to compare the cost-effectiveness of alternative diagnostic strategies just by using economic terms when differences in health care systems, facilities availability, examination costs and reimbursement charges are also factors. For instance, in our country the execution of a DMSA scan in all children with urinary tract infection followed by voiding cystourethrography in select cases would be approximately 20% less expensive than the opposite option. Furthermore, we believe that cost-effectiveness should take into consideration side effects and complications of the involved procedures, acceptance by the patient and even radiation exposure, which is clearly greater in the case of voiding cystourethrography. More importantly, the possible repercussion of missing the diagnosis of vesicoureteral reflux is a concern. Since many authors have suggested a wider use of DMSA imaging in children with urinary tract infections, we purposely planned our study to clarify the prognostic consequences of restricting the use of voiding cystourethrography to a select group of patients. We believe we have demonstrated that, from a statistical viewpoint, both diagnostic strategies are equally reliable. However, we are aware t h a t the management of the individual patient is not a statistical problem. Therefore, we stressed that the choice of the best diagnostic approach for the child with urinary tract infection should be based on the clinical presentation as well. Accordingly, candidates for voiding cystourethrography should include not only children with scarring but also those with febrile illnesses, exactly a s Noe does to select the patients without reflux for DMSA scintigraphy. In this way only 5% of those with reflux (and not 30%)would have been missed. Of those children 4 no longer had reflux a t followup. Conversely, Noe's strategy would have caused 2 renal scars to be missed. Since the risk of end stage renal disease in urinary tract infection is much more directly related to the presence of renal scarring than to vesicoureteral reflux, it is conceivable that our approach would eventually prove to be safer and then more cost-effective. Finally, regarding the allusion to the vested interest t h a t nonclinicians may have in promoting their techniques, we believe that this must be considered in relation to the vested interest of many clinicians, who continue to use investigations that do not represent the state of the art, just because they are used to or are directly involved in their execution.
RE: PENILE SENSITIVITY IN PATIENTS WITH PRIMARY PREMATURE EJACULATION
Z. C. Xin, W . S. Chung. Y. D. Choi, D. H . Seong, Y. J . Choi and H. K. Choi
J. Urol., 156: 979-981, 1996 To the Editor. We commend this attempt to uncover possible biological causes of premature ejaculation, a dysfunction that is, as the authors imply, poorly understood. However, we would like to note that we addressed this same issue in 1993.1 Contrary to the findings of Xin et al, we were unable to distinguish men with premature ejaculation from age-matched controls based on penile sensitivity. While our study was limited by small sample sizes, it nevertheless had the advantage of using a n experimenter blind procedure in which the stimulus was applied without active participation of the
LETTERS TO T H E EDITOR RepLy by Authors. We would not combine endoureterotomy with intracorporeal lithotripsy for ureteral stones unless there was a previously proved ureteral stricture. It is not uncommon for edema or n ring-like constriction below a ureteral stone to resolve completely once the stone is removed, making ureterotomy unnecessary and perhaps meddlesome. The use of ureteral stents after ureteroscopy is interesting. The usual teaching is that if the ureteral orifice is balloon dilated to facilitate ureteroscopy, edema can occur thereafter creating obstruction and pain. With the advent of small mini-ureteroscopes combined with laser lithotripsy it is highly probable t h a t in many cases the requirement for a stent may be eliminated. We are currently conducting a randomized prospective trial of stent versus no stent for ureteroscopy patients not undergoing dilation of the ureteral orifice. When using the holmium:YAG laser endoscopically proper precautions must be taken to avoid not only ureteral wall injury but damage to endoscopic or other endourological equipment in proximity to the activated laser fiber. The fiber must extend 1to 2 mm. beyond the tip of the endoscope to avoid damage to the optics. Likewise, this powerful tool has the capability of cutting through guide wires or wire baskets. Such complications can be avoided with attention to technique and by taking advantage of the fact t h a t ho1mium:YAG laser energy is absorbed within 1 mm. water at the settings commonly used for laser lithotripsy.
RE: ALTERNATIVE APPROACHES TO THE PROGNOSTIC STRATIFICATION O F MILD TO MODERATE PRIMARY VESICOURETERAL REFLUX IN CHILDREN
R. Sciagru, M. Materassi, V. Rossi, R. Ienuso, A . Danti and G. LaCaua J. Urol., 155: 2052-2056, 1996
To the Editor. The authors suggest in this report that to perform technetium-dimercapto-succinic acid (DMSA) renal scans in all children with urinary tract infections and followup with voiding cystography only in those with scars would be cost-effective. Despite this conclusion, they include neither numerical support for their supposition nor figures for cost. In fact, the DMSA scan in most cases is 4 times t h e cost of a voiding cystourethrogram. If, indeed, the authors' premise is followed by performing DMSA scans on all children with urinary tract infections and then following those with upper tract changes with voiding cystourethrograms, the cost for the 105 children in this series would have been approximately $71,000. By doing the opposite, a s we currently practice, obtaining voiding cystourethrograms in all children with urinary tract infections and then DMSA scans in those with reflux or febrile illnesses, the cost would only be $51,720. The suggested approach not only is not cost-effective, but i t actually costs 40% more to evaluate this group of children. However, the greater concern of this approach is not the costeffectiveness but rather that 30%' of the children in this group with infections who have r e f l w will be overlooked. Even if disease is low grade, the authors clearly state t h a t a third of their children with low grade reflw, defined as grade 2, had renal scars. While the authors state t h a t they do not know the effect of missing this 30% with reflux, I believe the repeated urinary tract infections, propensity for renal scarring and ultimate need for evaluation would be deleterious. Additionally, from their data, if one is concerned with trying to predict persistent reflux, the presence of grade 3 reflux is virtually a s good as their combination of voiding cystourethrogram and DMSA scan (76% versus 84%). In the final analysis, the suggested approach by the authors will not alter the overall urological management of children with reflux and infections, and is probably more costly than cost-effective with no more predictive value for persistent reflux than simple r e f l u grading alone. Additionally, almost 30% of the children with reflux and infections a r e at risk for having the r e f l w missed. I t still seems
99m
prudent to tailor the management of a pediatric urinary tract infection to the clinical picture rather than to technical testing in which nonclinicians may have a vested interest. Respectfully,
H. Norman Noe Pediatric Urology University of Tennessee, Meniphis College of Medicine 770 Estate Memphis. Tennessee 38120 Reply by Authors. It is tricky to compare the cost-effectiveness of alternative diagnostic strategies just by using economic terms when differences in health care systems, facilities availability, examination costs and reimbursement charges are also factors. For instance, in our country the execution of a DMSA scan in all children with urinary tract infection followed by voiding cystourethrography in select cases would be approximately 20% less expensive than the opposite option. Furthermore, we believe that cost-effectiveness should take into consideration side effects and complications of the involved procedures, acceptance by the patient and even radiation exposure, which is clearly greater in the case of voiding cystourethrography. More importantly, the possible repercussion of missing the diagnosis of vesicoureteral reflux is a concern. Since many authors have suggested a wider use of DMSA imaging in children with urinary tract infections, we purposely planned our study to clarify the prognostic consequences of restricting the use of voiding cystourethrography to a select group of patients. We believe we have demonstrated that, from a statistical viewpoint, both diagnostic strategies are equally reliable. However, we are aware t h a t the management of the individual patient is not a statistical problem. Therefore, we stressed that the choice of the best diagnostic approach for the child with urinary tract infection should be based on the clinical presentation as well. Accordingly, candidates for voiding cystourethrography should include not only children with scarring but also those with febrile illnesses, exactly a s Noe does to select the patients without reflux for DMSA scintigraphy. In this way only 5% of those with reflux (and not 30%)would have been missed. Of those children 4 no longer had reflux a t followup. Conversely, Noe's strategy would have caused 2 renal scars to be missed. Since the risk of end stage renal disease in urinary tract infection is much more directly related to the presence of renal scarring than to vesicoureteral reflux, it is conceivable that our approach would eventually prove to be safer and then more cost-effective. Finally, regarding the allusion to the vested interest t h a t nonclinicians may have in promoting their techniques, we believe that this must be considered in relation to the vested interest of many clinicians, who continue to use investigations that do not represent the state of the art, just because they are used to or are directly involved in their execution.
RE: PENILE SENSITIVITY IN PATIENTS WITH PRIMARY PREMATURE EJACULATION
Z. C. Xin, W . S. Chung. Y. D. Choi, D. H . Seong, Y. J . Choi and H. K. Choi
J. Urol., 156: 979-981, 1996 To the Editor. We commend this attempt to uncover possible biological causes of premature ejaculation, a dysfunction that is, as the authors imply, poorly understood. However, we would like to note that we addressed this same issue in 1993.1 Contrary to the findings of Xin et al, we were unable to distinguish men with premature ejaculation from age-matched controls based on penile sensitivity. While our study was limited by small sample sizes, it nevertheless had the advantage of using a n experimenter blind procedure in which the stimulus was applied without active participation of the