Your legal obligation
You have a legal obligation to notify the Driver and Vehicle Licensing Agency (DVLA) of a condition that lasts longer than three months and may affect your fitness to drive. Conditions such as pituitary tumour should be notified.
Many people with pituitary conditions will find there is no restriction, but you should check with your GP.You will likely only not be able to drive if your pituitary conditions causes eyesight problems. Transsphenoidal surgery does not in itself limit your entitlement to drive. Your doctor or specialist will give you full advice. More information about driving and medical conditions can be found on the Gov.UK website.