Introduction: Interspinous Process Distraction devices (IPD) aim to alleviate back and leg pain by limiting lumbar extension and unloading the disc. IPDs may offer a treatment option for symptomatic degenerative disc disease (DDD).
Methods: • Randomized, controlled clinical trial was conducted at 23 US centers, comparing the safety and effectiveness of IPD and non-operative care at 2 years follow-up for treatment of moderate low back pain with or without leg pain secondary to DDD. 278 patients were randomized and treated as follows: Investigational group (n=181) received IPD implantation and Control group (n=97) received a combination of patient education, medication, physical therapy, and/or steroidal injections (with crossover option after 6 months).
• The 12-month primary endpoint was Overall Success, a composite variable including: 1) Oswestry Disability Index (ODI) improvement of =15 points; and 2) no serious adverse event (AE) related to treatment; and 3) no secondary surgery. Other secondary outcomes were analyzed. Statistical analyses used Bayesian methods with non-informative priors. Last observations were carried forward for patients having secondary surgery or lost to follow-up.
Results: • Baseline demographics and ODI scores were statistically similar for both groups. The investigational group Overall Success was statistically superior to control (observed rate of 63.0% vs 13.4%, respectively; posterior probability of superiority (pps) >99.9%). The improvement in outcomes for IPD was statistically superior to control (pps >99.9%) for ODI (26.4 vs. 1.0), back pain (8.4 vs. 1.2), leg pain (4.9 vs. +1.1 pain increase in control group). Fifteen (8.3%) IPD and 34 (35.1%) control patients experienced a treatment-related serious AE. By 24 months, twenty (11.0%) IPD and 67 (69.1%) control patients had secondary surgery at the index level (of which 57 (58.8%) crossed over to IPD).
Conclusions: • Analyses support the superiority of this IPD over conservative care for back pain due to moderate DDD.
Patient Care: Demonstrate effectiveness and safety of interspinous distraction in management of back pain due to moderate degenerative disc disease.
Learning Objectives: 1. Understand the biomechanical properties of the IPD and how it unloads the three joint lumbar motion segment.
2. Understand the design and results of this randomized control multicenter trial comparing the IPD to a control of conservative management.
3. Form a conclusion based on the presented data on the superiority and safety of IPD in management of back pain due to moderate DDD.