A surgical probe (20, 66, 120) including a dilator (38, 76) and a method for forming and enlarging an access opening through a psoas muscle (108) to provide for minimally invasive lateral approach for surgical access to a lumbar intervertebral disc (104). A distal end portion (122) of the probe (120) is equipped with an electrode (140) useful for confirming proper location of the probe and includes an inflatable dilator body (124) for enlarging an access opening through tissue adjacent to a spinal column (106). The probe (120) includes a cannula (130) through which a K wire can be extended to anchor the probe to a patient.