A medical instrument and method which permits a suture to be introduced and removed through a single cannula which leaves only a relatively small wound. The instrument employs a trocar having an elongate member having a push button at a proximal end, a sharp point and blade at a distal end, a notch formed in the trocar a short distance proximally from said distal end and an aperture through the center of the trocar extending from an opening at the proximal end to an opening at the distal end. The trocar fits within a cannula including a hollow tube having a handle at the proximal end for gripping the cannula with two fingers. A spring keeps the notch within the cannula except when the push button is depressed. The device is used by inserting the trocar in the cannula and forcing the trocar and cannula through the body of a patient. Thereafter, a suture is inserted inside the body of the patient for ligation or retraction by feeding the suture through the aperture in the trocar. Once the suture is introduced, it is manipulated around the structure to be ligated or retracted. Then, the suture is placed in the notch of the trocar and the trocar is pulled out of the cannula, which pulls the end of the suture out of the cannula as well.