The venous drainage of the corpora cavernosa in the human penis

Abstract

Objective: To study the drainage proportions from the corpora cavernosa in defrosted human cadavers, as the veins related to penile erection were recently depicted to comprise the deep dorsal vein (DDV), a pair of cavernous veins (CVs) and two pairs of para-arterial veins (PAVs), as opposed to a single DDV between Buck's fascia and the tunica albuginea of the human penis.

Materials and methods: With no formalin fixation, 10 defrosted male human cadavers were used for this study. After injecting a 10% solution of colloid, and with the intracavernous pressure (ICP) fixed at 90 mmHg, the perfusion rate was recorded before and after the DDV, CVs and PAVs were removed, respectively. Finally, measurements were again recorded after penile arterial ligation. Cavernosography was used if required.

Results: The mean (range) perfusion rate for maintaining the ICP at 90 mmHg was 30.2 (15.5-90.8) mL/min, whereas the arterial perfusion rate was 2.8 (0.3-3.9) mL/min. The mean (range) drainage proportion of the corpora cavernosa was 60.5 (50.3-69.7)%, 11.9 (5.8-22.9)% and 11.4 (5.2-15.0)% via the DDV, CVs and PAVs, respectively. The remaining drainage proportion was 15.6 (14.1-18.1)%. This study shows the separate drainage contributions of the DDV, CVs and PAVs to the corpora cavernosa of the human penis.

Conclusion: We conclude that the venous drainage system of the corpora cavernosa is much more complex than the previous depictions of it, and the consequent focus on a single DDV. This also shows the independent role of each venous system.

Keywords: CVs, cavernous veins; Cadaver; Cavernous vein; Corpora cavernosa; DDV, deep dorsal vein; Drainage; ED, erectile dysfunction; ICP, intracavernous pressure; PAVs, para-arterial veins; Venous.

Figure 1

A schematic illustration and photographs of a representative cadaver in the study. (A) An illustration of the surgical approach and the placing of two scalp needles in the corpora cavernosa. A semi-circumferential incision was made, followed by a dorsal median longitudinal incision extending to the upper margin of symphysis pubis. Two 19-G scalp needles were inserted and firmly fixed in place with 4–0 silk sutures at the 3 and 9 o’clock positions, respectively. One was connected to monitor the ICP, whereas the other was used for infusion of a 10% colloid solution. (B) A representative photograph of a cadaver. This penis was well-prepared with the necessary arrangement depicted in Panel A. It was ready for the overall haemodynamic study with the ICP simultaneously measured. (C) The penis was infused with the 10% colloid solution and the flow rate was recorded, while the ICP oscillated around 90 mmHg. A ventral curvature was characteristic in this cadaver.

Figure 2

A perfusion rate recording of a representative cadaver (No. 6 in Table 1). (A) An overall haemodynamic study was first made and the perfusion rate was measured as 94.0 mL/min (arrow) while the ICP was oscillating around 90 mmHg. The upper tracing shows the ICP (mmHg), and the lower one represents the infusion flow of 10% colloid solution. (B) This tracing was likewise made after the DDV and its branches were removed. The perfusion rate was 36.5 mL/min (arrow). (C) Similarly, the perfusion rate of 30.1 mL/min (arrow) was recorded after the CVs were stripped and then ligated. (D) The PAVs were ligated segmentally only. Again a perfusion rate of 16.5 mL/min (arrow) was recorded. (E) Finally, the penile artery was identified and ligated at the branching point of the dorsal and cavernous artery proximally. The perfusion rate was 13.3 mL/min (arrow). It was used for calculating the assumed arterial perfusion rate, and a corrected perfusion rate was made in each setting.

Figure 3

Cavernosograms taken in the cadaver of a 67-year-old man. (A) While the tip of a 19-G scalp needle (black asterisk) was positioned in the corpus cavernosum (white asterisk) the DDV (black arrows) is shown after injection with the contrast medium. Note that the femoral vein (cross) was full of blood clots in this defrosted cadaver. (B) Those venous tissues on Panel A were difficult to see after the PAVs were removed and the corpora cavernosa (white asterisk) was better opacified.

Figure 4

An illustration and photographs of penile venous stripping surgery. (A) This illustration stresses the positions of the ligatures placed on the venous stumps to render a watertight milieu of the corpora cavernosa and thus enable the application of Pascal’s law. The DDV system was first removed, followed by the CV system, and the PAVs which were ligated only, in sequence. The sites of these ligatures should be as close to the tunica albuginea as possible. Finally, the penile artery was ligated at the branching point of the dorsal and cavernous artery proximally. Care should be taken, as a rupture of the tunica albuginea would ruin the watertight milieu necessary to apply Pascal’s law. (B) Ongoing penile venous surgery; the DDV (left arrow) was first stripped and ligated closest to the tunica albuginea with 5–0 Nylon sutures, then the CV (right arrow) was similarly treated after cavernosometry. It was continued as proximal as possible. (C) The PAVs were segmentally ligated while the medial and lateral ones (inserted arrows) were meticulously treated after removing of the DDA and CV, which left a dorsal groove (arrows).