Multiple laminotomies compared with total laminectomy in central stenosis. A prospective randomized study.

Bilateral laminotomy at 2 or 3 levels required a significantly longermean operative time than total laainectomy at an equal nuiber of levels.Mean blood loss was siiilar in comparable subgroups ( equal number ofdecompressed levels ) in the three groups. Similar proportions ofsatisfactory clinical results were obtained in the three groups ( 8U, 78%and 78%, respectively). Neural complications consisted in mild to markeddeficits of a single nerve root; their incidence was higher in Group I (lU)than in Group II (0%) or III (3%). No patients in Group I showed evidence ofvertebral instability, while this occurred in 3 patients in Groups II orIII, who had lumbar scoliosis or degenerative olysthesis preoperatively. Ofthe 5 patients in Group I who underwent MRI postoperatively, 3 had nocompression of the neural structures at the decompressed levels, while twoshowed mild indentation on the posterolateral aspect of the thecal sac. Nobony compression was evident in patients in Group II or III.CONCLUSIONS. Multiple laminotomies, which appear to better preservevertebral stability, -is the treatment of choice in all patients with-developmental stenosis and in those with mild to moderate degenerativestenosis or degenerative olysthesis. Total laminectomy is to be preferred inpatients with severe stenosis when the involved motion segments are stablepreoperatively; when this is not the case, the choice is between multiplelaminotomies and laminectomy associated with arthrodesis. Total laminectomyshould be performed in the presence of degenerative olysthesis greater than30%.