A minimally invasive retractor system is shown which has a support frame having two opposing pairs of horizontally oriented sides. The sides of the frame can be adjusted to vary an interior space of the frame. Four retractor blades are mounted on the frame for engaging tissue within a surgical site. Each retractor blade has an elongate body portion with a length which is oriented perpendicularly to the frame in use. One of the retractor blades can be equipped with a light source and a suction source which are integral to the blade. The blade also has an integral power source for powering the light source. The blade can also house a tissue retractor such as a dural retractor for retracting the dural sack of a patient during spinal surgery.