Bratt, who was awarded an MBE by the Queen in her 2009 Birthday Honours List for his services to sport, underwent a first operation last summer but was admitted to hospital again on Monday to try and clear up the problem.
It is unclear at this stage how long he will be forced to stay away from Vale Park but early indications suggest the procedure has been a positive one.
Director Graham Mudie has taken over Bratt's responsibilities until further notice.
The club's official website said: "Everybody at Port Vale would like to take this opportunity to wish Bill a speedy recovery to full health."
Source: Team Talk
