Praise be to Allah, Lord of the Worlds, and may His peace and blessings be upon our Prophet Muhammad and upon all his family and companions.
It is permissible for the one who suffers from urinary incontinence to lead prayer even if this condition continues during prayer so long as he wears a diaper and performs ablution for every prescribed prayer at its time for his prayer-as an Imam-is valid. Moreover, Shafiee' jurists stated that the prayer of the people praying behind the Imam is valid even if the latter has urinary incontinence. This is by analogy to the validity of following an Imam who has performed Tyamumm (Dry ablution).
Furthermore, [Matin Al-Minhaj] states: "The stronger opinion of the Maliki doctrine reads: "The prayer of those led by an Imam who has urinary incontinence is valid, but reprehensible." In conclusion, the prayer of such an Imam and those following him is valid, and the latter aren`t obliged to redo their prayer. And Allah Knows Best.