A method for delivering fluid to a brain of a subject using a modular fluid delivery apparatus is described. The method comprises taking a subject having a first part of the modular fluid delivery apparatus subcutaneously implanted therein, the first part of the modular fluid delivery apparatus comprising a first end having a first fluid connector portion attached thereto and a second end being connected to one or more catheters implanted within the brain of the subject. The method also comprises taking a second part of the modular fluid delivery apparatus, the second part comprising a third end comprising a second fluid connector portion. The method further comprises making an incision in the subject to gain access to the first fluid connector portion of the first part of the modular fluid delivery apparatus, and connecting the first fluid connector portion to the second fluid connector portion.