A neurosurgical kit includes a catheter and a guide tub. The catheter includes a distal section of tubing having a distal end with a port or ports for delivering fluid to a target site within the brain. The distal section of tubing has an outer diameter that is smaller than an internal diameter of the guide tube. The catheter and guide tube are arranged such that, when the catheter is inserted into the guide tube to locate the port or ports at the target site, a recess is provided in a distal end section of the guide tube between the guide tube and the distal section of tubing of the catheter.