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The neuroanatomy of erection in men is not well defined. Recently, we isolated successfully the cavernous nerves for acute and chronic neurostimulation to induce penile erection in dogs and monkeys. We then investigated the anatomy of these nerves in humans by cadaveric dissection and serial histologic sectioning. Our experience in tracing the spinal nuclei responsible for vesical and urethral function by transportation of horseradish peroxidase enabled us to explore the location and organization of the spinal center for erection. Thus, systemic knowledge of the neuroanatomy of erection was accumulated. The spinal nuclei for control of erection are located in the intermediolateral gray matter at the S1 to S3 and T12 to L3 levels in dogs, and the S2 to S4 and T10 to L2 levels in humans. From these sacral nuclei axons issue ventrally and join the axons of the nuclei for the bladder and rectum to form the sacral visceral efferent fibers. These fibers emerge from the anterior root of S2 to S4, and join the sympathetic fibers to form the pelvic plexus, which then branches out to innervate the bladder, rectum and penis. The fibers innervating the penis (cavernous nerves) travel along the posterolateral aspect of the seminal vesicle and prostate, and then accompany the membranous urethra through the genitourinary diaphragm. These fibers are located on the lateral aspect of the membranous urethra and ascend gradually to the 1 and 11 o'clock positions in the proximal bulbous urethra. Some of the fibers penetrate the tunica albuginea of the corpus spongiosum, while others spread to the trifurcation of the terminal internal pudendal artery and innervate the dorsal, deep and urethral arteries. Shortly before the 2 corpora cavernosa merge the cavernous nerves penetrate the tunica albuginea along with the deep artery and cavernous vein. The terminal branches of these nerves innervate the helicine arteries and the erectile tissue within the corpora cavernosa. Because of the intimate relationship of the cavernous nerves to the rectum, prostate and urethra, they can be damaged easily during urological and pelvic procedures. This systemic knowledge of the human cavernous nerves from the spinal center to the erectile tissue should permit a better understanding of erection and impotence. Furthermore, with the aid of intraoperative neurostimulation, the cavernous nerves may be identified and preserved, thereby preventing iatrogenic impotence.

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Eleven segmental and eight total renal artery occlusions were evaluated by sonography in transplanted kidneys of 19 adult mongrel dogs. The segmental occlusions were serially scanned daily or every other day for up to 35 days. The total occlusions were scanned daily for up to 10 days. Each occlusion was confirmed angiographically, and kidneys were examined pathologically. Acute segmental renal artery occlusion produces a sequence of sonographic changes, beginning with a focal hypoechoic mass at 24 hr, which stays unchanged for 5-7 days. At 7 days, internal echoes appear, and the infarct slowly consolidates to an echogenic, slightly depressed focus at 17 days. Total renal artery occlusion produced no appreciable change in cortical echogenicity and only slight increase in size. Acute segmental renal infarction can be detected early in its course and demonstrates a sequence of changes that may aid in dating the infarct. Total renal infarction may appear normal sonographically, and further studies are needed to confirm that diagnosis.

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The sonographic and Doppler features of acute spermatic cord torsion were investigated in eight dogs. Serial sonography following torsion demonstrated unambiguous abnormalities in all experimental subjects within one hour. The observed abnormalities included increase in size of the spermatic cord, testis, and epididymis, decrease in echogenicity of the testis and epididymis, and loss of Doppler signal from the cord. Sonographic abnormalities were clearly visible before any histologic change was detected and well in advance of the onset of cellular necrosis. Since every experimental subject had an abnormal testicle, the identification of a normal testicle in a clinical setting is felt to exclude torsion. Combined gray-scale sonographic and Doppler features appear promising in the diagnosis of acute spermatic cord torsion and its distinction from acute epididymo-orchitis.

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One hundred patients with benign disease of the upper urinary tract were operated on: 50 through the standard flank approach and 50 through the dorsal approach. The analgesic requirement for control of postoperative pain was less for patients operated on through the dorsal incision, and these patients had a shorter postoperative ileus and a hospital stay an average of 4.29 days less than those operated on through the flank approach. The dorsal lumbotomy incision is recommended for certain operations on the kidney and proximal ureter.

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