A method for percutaneously accessing the lumbar region of the spinal column by laterally inserting a cannula through the patient's side above the pelvic crest to contact a predetermined position in the lumbar region and passing objects such as medical instruments through the cannula. This method is useful for performing percutaneous lumbar diskectomies by cutting a portion of the patient's disc capsule and nucleus through the cannula and removing a desired amount of nucleus material. The cannula has a tubular member and anchor means attached to one end of the member for anchoring the cannula in body tissue to prevent shearing movement between it and the tissue. Other instruments for performing a percutaneous lumbar diskectomy are disclosed, including a speculum and trocar for percutaneously inserting the cannula into the patient's body, a diskectomy knife for cutting disc nucleus material and rongeur forceps for removing the disc material. The above instruments may be combined in a surgical apparatus.