Is it permissible for a wife to use vaginal dilators (medical sex tools) based on a doctor's recommendation to treat involuntary vaginismus?

There is no harm in using vaginal dilators to treat vaginismus, as long as it is not for the purpose of unlawful pleasure. This can be done with the husband's assistance, because masturbation by the husband's hand is permissible.

And assuming that the use of dilators leads to arousal or masturbation, and its purpose is treatment, then there is no harm in that, so that the wife can engage in intercourse and achieve the purpose of marriage. A group of jurists have permitted masturbation out of necessity, committing the lesser of two evils.

Al-Mardawi said in "Al-Insaf" (10/252): "Two benefits: First: Masturbation is not permissible except out of necessity... Second: The ruling for women in this regard is the same as for men." End quote.