Twenty-one cases of lumbar dislocations have been analyzed. A classification based on pathological anatomy is presented. Differences and similarities of the various types are pointed out.

Faults of lumbar segmentation may favor the occurrence of lumbar dislocation.

Eleven (53 per cent) of twenty-one patients with dislocation had a neural deficit. It is known that progressions of neural deficit occurs frequently but that the potential for recovery is great. Therefore precisely correct treatment is extremely important.

Early open reduction, internal fixation, and posterior fusion is recommended as the treatmen of choice in all types of lumbar dislocation with or without neural deficit. In our hands this treatment has been uniformly successful with no progression of neural deficit, recovery from neural deficit, no significant postoperative back pain, no need for secondary spine operations, best cosmetic end result (absent or minimum gibbus), and no local postoperative complications.

Non-operative treatment, closed reduction, and operation without internal fixation are all condemned as dangerous. Five of the eleven patients treated by a regimen other than open reduction, internal fixation, and refusion required late secondary spine operations.

In our patients in whom wire fixation and two-segment fusion were used there was not a single instance of recurrent dislocation. It would appear therefore that the Meuhrig-Williams spine plates and four-segment fusion are usually excessive treatment and may contribute to postoperative disability.

In the vast majority of patients, laminectomy has no place in the initial treatment of the injuries because it is unnecessary and relatively ineffective, and may be detrimental.