Clinical Outcomes and Quality of Life 1 Year after Open Microsurgical Decompression or Implantation of an Interspinous Stand-Alone Spacer

Background: Interspinous stand-alone implants are inserted without open decompression to treat symptomatic lumbar spinal stenosis (LSS). The insertion procedure is technically simple, low-risk, and quick. However, the question remains whether the resulting clinical outcomes compare with those of microsurgical decompression, the gold standard. Material and Methods: This prospective, comparative study included all patients (n = 36) with neurogenic intermittent claudication (NIC) secondary to LSS with symptoms improving in forward flexion treated operatively with either interspinous stand-alone spacer insertion (Aperius (R); Medtronic, Tolochenaz, Switzerland) (group1) or microsurgical bilateral operative decompression (group 2) between February 2007 and November 2008. Data (patient data, operative data, COMI, SF-36 PCS and MCS, ODI, and walking tolerance) were collected preoperatively as well as at 6 weeks, at 3, 6, and 9 months, and at one year follow-up (FU). All patients had complete FU over 1 year. Results: Compared to preoperative measurements, surgery led to improvements of all parameters in the entire collective as well as both individual groups. There were no statistically relevant differences between the 2 groups over the entire course of FU. However, improvements in the ODI and SF-36 MCS were not significant in group 1, in contrast to those of group 2. Also, although in group 1 the improvements in leg pain (VAS leg) were still significant (p < 0.05) at 6 months, this was no longer the case at 1 year FU. In group 1 at 1 year FU an increase in leg pain was observed, while in group 2 minimal improvements continued. Walking tolerance was significantly improved at all FU times compared to preoperatively, regardless of group (p < 0.01). At no time there was a significant difference between the groups. In group 1, admission and operative times were shorter and blood loss decreased. The complication rate was 0% in group 1 and 20% in group 2, however reoperation was required by 27.3% of group 1 patients and 0% of group 2. Conclusion: Implantation of an interspinous stand-alone spacer yields clinical success comparable to open decompression, at least within the first year of FU. The 1-year conversion rate of 27.3% is, however, decidedly too high.