From the material analyzed in this study it appears that, if a hundred patients with inerniated nucleus pulposus are subjected to disc excision, one may expect sixty of them to obtain long-term results which are satisfactory. If the same hundred patients should have spine fusions in addition to the disc excisions, the results will be satisfactory in seventy of them. Sixty of these patients would not have needed the fusion operation, and of the forty whose results are unsatisfactory only ten could have expected sufficient improvement to make them satisfactory. Furthermore, the fusion procedure is an added operation, and we have no reason to believe that its effectiveness is greater if it is done at the time of the disc excision than if it is performed at a later date as a second-stage operation. We are therefore led to the conclusion that, when surgical intervention is necessary for simple cases of herniated nucleus pulposus, the operation of choice is disc excision only. Spine fusion can be performed at a later elate in those patients whose poor results warrant additional surgery.

Recognition is given to the fact that technical improvements in the operative procedures may be expected. Such improvements may lead to results which differ from those found in this study and will justify a re-evaluation after a lapse of years.