Midterm Outcomes of a Prospective Multicenter Randomized Controlled Trial Comparing the Clinical Efficacy of Interspinous Spacers as a Treatment for Moderate Lumbar Spinal Stenosis
Section snippets
Background Context
Mild intermittent neurogenic claudication secondary to lumbar spinal stenosis (LSS) is treated conservatively while severe symptoms often require decompression surgery. A therapeutic gap remains for patients with moderate LSS whose symptoms remain resistant to nonoperative care.
Purpose
To evaluate the mid-term clinical outcomes of patients with intermittent neurogenic claudication secondary to radiographically confirmed moderate LSS who were treated with 1 of 2 interspinous spacers including a novel minimally invasive device.
Study Design/Setting
Prospective, multi-center, randomized, controlled, FDA investigational device exemption (IDE) trial.
Patient Sample
145 patients with intermittent neurogenic claudication secondary to moderate LSS which failed to respond to conservative care.
Outcome Measures
Condition-specific Zurich Claudication Questionnaire (ZCQ), back function with Oswestry Disability Index (ODI), and back and leg pain severity with visual analogue scale (VAS).
Methods
Patients were randomized to receive either an interspinous device inserted through a minimally invasive approach (Superion, Vertiflex, San Clemente, CA; n=75) or a FDA-approved device (X-STOP, Medtronic, Memphis, TN; n=70). Subjects were followed at regular intervals through a minimum of 18 months after surgery.
Results
Relative to baseline values, ZCQ symptom severity and physical function scores improved between 33% and 36% in both groups through 18 months (p<0.001). ZCQ patient satisfaction scores at 18 months were 1.7±0.8 for Superion and 1.6±0.7 with X-STOP. Axial pain decreased from 55±28 mm before surgery to 23±26 mm at 18 months in the Superion group (p<0.001) and from 55±27 mm to 26±28 mm with the X-STOP (p<0.001; p=0.28 between groups). Lower extremity pain also decreased from 67±24 mm pre-treatment
Conclusions
Clinically meaningful improvements in axial and extremity pain and function are maintained through 18 months after surgery in patients with moderate LSS treated with interspinous spacers including a novel minimally invasive device.
FDA Device/Drug Status
Vertiflex (Investigational/Not approved), X-Stop (Approved for this indication).