Focus is on the conflict in the Congo, but it also occurs in other conflicts. 80% of men saved from Serb concentration camps in Sarajevo had been raped by the Serbs. When the Japanese invaded the Andaman Islands in 1944, many of the Indian men there were raped. Male rape was long practiced against enemy soldiers by Turks.
Sexual violence against male prisoners, which may or may not include rape, was also reported in El Salvador (80%) and Sri Lanka (30%).
The cases in the Congo are particularly egregious. Many of the men continue to bleed and are damaged internally, but I am not sure what exactly is wrong with them (other than that they are “ass-wrecked”), and I am not sure what can be done medically to remedy the problem.