Intervertebral inflatable distractors employing thecal sac retractors, and related systems and methods are disclosed. Adjacent vertebrae are spaced apart or distracted to prepare for the installation of intervertebral cages during spine surgery. An intervertebral inflatable distractor may include a inflatable portion having first and second inflation modes. In the lower-volume first mode, the inflatable portion may be efficiently received within the intervertebral space, then the higher-volume second mode may be used to abut against vertebrae endplates to urge them apart and thereby provide space to receive the cages. A thecal sac retractor of the intervertebral inflatable distractor may also be used to abut against the thecal sac to provide space for larger cages. In this manner, an interbody cage may be efficiently installed between vertebrae while minimizing injury to the vertebrae and the thecal sac.
