Pathologic significance of the internal pudendal vein in the development of intrapelvic venous congestion syndrome

Abstract

The insufficient circulation of the internal pudendal vein is a characteristic sign observed in the patient with intrapelvic venous congestion syndrome (IVCS). The present study was designed to reveal the pathophysiological significance of it in IVCS. Twenty-seven men with IVCS and nine men without IVCS were used in this study. The circulatory status in the internal pudendal vein was evaluated by three dimensional magnetic resonance venography (3D-MRV). From the coronal MRI (the original image of 3D-MRV) on the slice of the ischiorectal fossa, the thickness of the obturator internus muscle and the pararectal fatty tissue was measured. The interval between the ischial supine, locating at the bottom of the pelvis, was also measured. Using eleven cadavers, the pelvic cavity was examined carefully in terms of the course of the internal pudendal vein. The finding of interruption in the internal pudendal vein by 3D-MRV was observed at the ascending portion in all cases with IVCS. Although the thickness of the obturator internus muscle was not significantly different between two groups, the thickness of the pararectal fatty tissue in IVCS group was significantly thinner as compared to control group (3.0 +/- 0.4 vs 3.6 +/- 0.1 cm, p < 0.01). The interval between the ischial supine in IVCS group was significantly narrower as compared to control group (7.9 +/- 1.1 vs 9.4 +/- 0.5 cm, p < 0.01). In cadavers, it was confirmed anatomically that the ascending portion of the internal pudendal vein passed through the pudendal canal (the Alcock's canal) accompanied by the internal pudendal artery and the pudendal nerve. It was suggested that anatomical factors, such as the thinner pararectal fatty tissue or the narrower interval between the ischial supine, might cause the development of IVCS, according to the compression of the Alcock's canal.