Anatomic study of vaginal width in male-to-female transsexual surgery.

Despite the recent improvement in the design of male-to-female sex reassignment operations to enlarge the vaginal vault and depth, the size of the neovagina remains somewhat limited and the exterior of the neovagina may be compressed by the bony structure of pubic rami. The purpose of this study was to determine by anatomic study the possible cause of this limitation. Eighteen male and 10 female cadavers were dissected to measure the distance between the bilateral bony pubic rami (interramic distance) at a level that corresponds to the same level in the vaginal canal of females. At the same level of the vaginal canal in the female, which corresponds to the lower border of the prostate in the male, empirically 3 cm below the bony symphysis pubis, the mean value of the interramic distance was 3.95 +/- 0.25 cm in the male and 5.20 +/- 0.36 cm in the female (p = 0.000). The interramic distance in the male and female is significantly different. In those who have undergone the male-to-female transsexual operation, the newly structured vagina may be ventrolaterally limited. Several factors cause narrowing of the vaginal orifice in male-to-female transsexuals. On the basis of this study, it seems that the bony structure of the pubic rami compresses the vagina ventrolaterally. This finding may suggest refinements of the structural design of the neovagina and prompt procedural changes in male-to-female sex reassignment operations. Future investigation should be directed toward modifying vaginoplasty so that neovaginal width can be increased to the patient's satisfaction.