My gut feeling is that visceral manipulation is yet another sCAM practice based on falsehoods, an economy of truth, and, basically, lies. Science-based medicine gives us the low down:
“I think we can reasonably assume that any abdominal manipulation sufficient to disrupt adhesions would risk tissue damage and internal bleeding, but [visceral manipulation] is not likely to do that. As practiced, VM amounts to relaxation, suggestion, and gentle massage; so it is not likely to cause physical harm unless it replaces other, effective treatments. It’s more likely to cause harm to the wallet and to critical thinking.