Coagulum-facilitated urethral diverticulectomy

variation can be significant and quantitative analysis of urinary solutes might be a prerequisite to a decision to lower the aminoglycoside dose in a given case. Classification of urinary excretion patterns also might prove helpful in deciding whether or not to reduce dosage, e.g., high urinary magnesium in patients with hydronephrosis4 or high urinary oxalate in patients with recurrent oxalate calculus. Harrison’ compared standard 15 mg/Kg body w/eight/day dosing of amikacin to half-dose therapy consisting of 7.5 mg/Kg/day in adult patients with established urinary tract infection. Duration of therapy was comparable in the two groups. Patients treated with the standard dosage regimen were infected most frequently with E. coli and Pseudomonas, whereas the most frequently isolated organisms in the half-dose group were E. coli and Proteus mirabilis. He concluded that the half-dose amikacin in the 25 patients of that group was equally effective as standard therapy in the 25 patients of the control group. Because MICs for all organisms isolated were 0.5- 16 mcg/ml and the mean urinary concentration of amikacin was 438 (32-1,452) mcg/ml, it is difBcult to interpret this as a low-dose aminoglycoside trial. While Stamey’s6 correlate of treatment of urinary tract infections with urine drug levels rather than serum levels is now widely accepted, we must keep in mind the possibility that any antibiotic theoretically may be inhibited by substances in the urine, precluding arbitrary dose reduction. Patricia A. Dahlin, Pharm. D. Clinical Pharmacy Specialist in Spinal Cord Injury James A. Haley Veterans Administration Hospital Tampa, Florida 33612 References 1. Minuth JN, Musher DM, and Thorsteinsson SB: Inhibition of the antibacterial activity of gentamicin by urine, J Int Dis 133: 14 (1976). 2. Zimelis VM, and Jackson GG: Activity of aminoglycoside antibiotics against Pseudomonas aeruginosa: specificity and site of calcium and magnesium antagonism, J If Dis 127: 663 (1973). 3. Medeiros AA, O’Brien TF, Wacker WEC, and Yulug NF: Effect of salt concentration on the apparent in vitro susceptibility of Pseudomonas and other gram-negative bacilli to gentamicin, J Inf Dis 124 (Suppl): S59 (1971). 4. Kinn AC, and Lins LE: Elevated magnesium excretion in hydmnephrotic kidneys, Stand J Urol Nephrol 16: 45 (1982). 5. Harrison LH: Treatment of complicated urinary tract infections with amikacin: comparison of low and high dosage, Urology 10: 110 (1977). 6. Stamey TA: Pathogenesis and Treatment of Urinary Tract Infections, Baltimore, Williams & Wilkins Co., 1980, pp. 54-60.

UROL.OGY

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AUGUST

1982

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VOLUME

Xx,

NUMBER

2

COAGULUM-FACILITATED DIVERTICULECTOMY

URETHRAL

the Editor: Most of the techniques used to facilitate excision of a urethral diverticulum require identification of the opening of the diverticulum, which can be difficult and often time-consuming. We present a quick, simple method for identifying the diverticulum and maintaining its configuration during dissection, without the need for catheterizing or manipulating its urethral opening. With the patient in the dorsal lithotomy position, the diverticulum is palpably identified. The vaginal mucosa is gently cleaned and a 20-F Angiocath is inserted transvaginally in the diverticulum mass, which is then aspirated for verification of position, appropriate cultures, and estimation of the size of the cavity. The diverticulum is then filled with coagulum injected via a single syringe as described by Kalash et al. * recently. The Angiocath is then removed, and the patient can be fully prepped without fear of decompressing the diverticulum. The vaginal mucosa is incised directly over the lesion and the diverticulum circumscribed and excised. This technique offers many advantages over those described previously: (1) Less time is required for mixing the solutions necessary for the formation of the coagulum than for repeating a urethroscopic procedure with often time-consuming and difficult catheterization. This initial part of the procedure also may be accomplished prior to induction of anesthesia. (2) There is no fear of decompression of the diverticulum during the surgical prep or during the dissection. (3) There are no catheters in the operative field to impede dissection or fall out during the procedure. (4) Direct cultures of the aspirated fluid and standard urine cultures are obtained. (5) Should the coagulum enter the bladder, this poses no problem since it totally dissolves in urine within twenty-four hours. (6) Finally, if the Anqiocath misses the mass on the first try, it can be replaced easily and accurately.

TO

Robert M. Berger, M.D. The Children’s Memorial Hospital Chicago, Illinois 60614 Harry C. Miller, M.D. George Washington University Washington,

*&slash precipitate

D.t

SS, Young JD, and Harne G: Modification coagulum pyelohthotomy technique. Urolop

:. 20037

of cryo19: 467

(1982).

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