Microdiscectomy with and without insertion of interspinous device for herniated disc at the L5-S1 level

The role of interspinous devices (ISD) after lumbar herniated disc surgery for the prevention of postoperative back pain is controversial. The aim of this comparative prospective study was to determine outcomes in a selective cohort with L5-S1 disc herniation and degenerative disc changes after microdiscectomy with or without insertion of an ISD. One hundred and two consecutive patients underwent an L5-S1 microdiscectomy with or without implantation of an ISD. Group 1 consisted of 47 patients, with mild (n=22), moderate (n=14) or severe (n=11) degenerative disc changes who had microdiscectomy alone. Group 2 comprised 45 patients with similar types of disc changes who underwent microdiscectomy with an ISD implant. The Visual Analogue Scale (VAS) was used to grade low-back pain and postoperative clinical status was rated according to the modified MacNab criteria. Mean VAS score for low-back pain improved significantly at 1 year follow-up from 7.3 at baseline to 2.75 (p<0.001) in Group 1 and from 6.7 to 1.5 (p=0.001) in Group 2. VAS score at 1 year showed significant improvements in 21 Group 1 patients versus 30 Group 2 patients (p=0.001). Forty four percent of Group 1 patients and 80% of Group 2 patients showed improvement using the modified MacNab criteria. Patients in both groups reported significant improvement in sciatic pain and disability after microdiscectomy with or without an ISD implant. Patients with mild degenerative disc changes were more likely to achieve improvement of their low-back pain when treated with both microdiscectomy and ISD insertion.