patients have undergone prostatic surgery, ninth is waiting to undergo prostatic surgery.
Arthur N. Tessler, M.D. 566 First Avenue New York, New York 10016
AIR CYSTOMETRY EMBOLISM
To the Editor: To date over 10,006 air cystometrograms have been performed under my supervision and many thousands of additional tests have been performed by others who use the Modern Controls air cystometer, which I popularized. To my knowledge, no deaths or other major complications have resulted from use ofthis instrument. I was, therefore, surprised and distressed to learn of the fatality which occurred during an air cystometrogram performed by Summers et al. * Even though the mechanism of air embolism in this case is unclear, it is unreasonable to conclude that the air cystometrogram was not somehow responsible for this patient’s death. I previously have been reluctant to change to carbon dioxide cystometry because the recorder of the Modern Controls air cystometer is superior to that of the only commercially available carbon dioxide cystometer. The latter disadvantage of carbon dioxide cystometry is clearly outweighed by the fact that air embolism, even though extremely rare, can occur with air cystometky. Modern Controls is presently designing an inexpensive kit which may be used to convert their air cystometers to carbon dioxide; thus, those who have purchased the instrument will not have to reinvest in a second cystometer. Until such conversion kit is available, I recommend that the Merrill air cystometer not be used clinically. Daniel C. Merrill, M.D. 150 Muir Road Martinez, California 94553 *Summers, J. L., Ford, M. L., Keitzer, W. A., Wilkerson, J. E.: Fatal air embolism following air cystometrogram, Urology 4: 95 (1974).
IMPORTANCE OF CAREFUL PALPATION OF VAS DEFERENS To the Editor: The article, “Congenital Absence of Vas Deferens with Ipsilateral Urinary Anomalies,” by by C. B. Emery, M.D., A. M. B. Goldstein, M.D., and J. W. Morrow, M.D., in the August issue (vol. 4, page 201) of UROLOGY serves to remind us of the importance of careful palpation of the vas deferens as part of a complete physical examination in every male, child and adult. It is the rule, rather than the exception, to have a normal testicle associated with congenital absence of the vas deferens on the same side, and to have bilateral normal testicles if the absence of the. vas deferens is bilateral. The embryologic development of the testes is from the genital ridges on the medial aspect of the mesonephros, while the vas deferens has a different origin- the mesonephric duct. If development is disturbed before the human embryo is at the 60-mm. (thirteen weeks) stage, it is possible to have a fully developed testicle and globus major of the epididymis with an undeveloped vas deferens, seminal vesicle, and ejaculatory duct. If the mesonephric duct ceased development at a very early stage (four weeks) the ureteric bud would not develop, and there would be an absence of the ureter and kidney.on the same side. As a practical point, when congenital absence of the kidney and ureter is suspected because of nonvisualization on an excretory urogram, the inability to palpate a vas deferens in the scrotum on that side will confirm the diagnosis. t The pediatrician should know that the diagnosis of cystic fibrosis in the male child can be ruled out if the vasa are palpable. Every male child with this congenital disorder has been found to have associated congenital bilateral absence of the vasa. It should also be remembered that calcification of the vasa is pathognomonic of diabetes. Richard D. Amelar, Lawrence Dubin, 137 East 36th New York, New York
M.D. M.D. Street 10016
tAmelar, R. D., and Dubin, L.: Male Infertility, Urology 1: 1 (1973).