RESULTS OF A TRIAL OF ANTERIOR OR CIRCUMFERENTIAL LUMBAR FUSION IN THE TREATMENT OF SEVERE ISTHMIC SPONDYLOLISTHESIS IN YOUNG-PATIENTS

The radiological and clinical results in 27 patients operated on for s evere isthmic spondylolisthesis at age < 20 years with uninstrumented anterior interbody fusion alone in 11 or combined anterior and postero lateral (circumferential) fusion in 16 are reported. The mean follow-u p time was 5.9 +/- 2.4 years. The two groups were comparable with rega rd to age at operation, sex, preoperative symptoms, mean preoperative slip and sagittal rotation angle. The follow-up assessment, made by an independent observer, included interview, Oswestry disability index, physical examination, functional tests, and plain radiographs. At foll ow-up, there were no statistical differences between the groups in sub jective, clinical, and functional outcomes. Follow-up radiographs show ed no progression of slip in either group. The sagittal rotation angle worsened slightly in the anterior fusion group but improved by 5.8 de grees (p < 0.001) on the average in the combined fusion group. There w ere no instances of pseudarthrosis. Two patients, one in each group, w ere reoperated on early for postoperative peroneal weakness; both reco vered. The clinical and functional results were satisfactory in most c ases. The radiological results concerning the sagittal rotation angle were superior in the combined fusion group, but whether this will affe ct the long-term clinical result is not known.