Cannula for receiving surgical instruments

A method of accessing a spinal surgical site in a patient, the method comprising:

• providing an access device having an elongate body with a proximal end and a distal end and defining a length between the proximal and distal ends, the access device having an outer surface for engaging the body of a patient and an inner surface at least partially defining a passage sized for receiving a plurality of surgical instruments used to perform a surgical procedure, the access device including an actuatable portion that is actuatable between an unexpanded configuration for insertion into the patient and an expanded configuration for retracting tissue to provide an enlarged surgical field at the spinal surgical site, wherein a cross-sectional area of the passage at a first location in the expanded configuration is greater than a cross-sectional area of the passage at a second location, wherein the first location is distal of the second location;
• providing an actuator configured to move the actuatable portion from the unexpanded configuration to the expanded configuration;
• inserting the access device into the patient such that the distal end is adjacent the spinal surgical site and the proximal end is outside the patient;
• moving the access device from the unexpanded configuration to the expanded configuration with the actuator, thereby increasing access to the spinal surgical site;
• and
• delivering more than one surgical instrument along an entire length of the passage to the spinal surgical site;
• wherein the actuator is configured to be inserted into the passage, wherein the step of moving the access device from unexpanded configuration to the expanded configuration includes engaging the inner surface of the access device with the actuator and applying a radially directed force against the inner surface.