485 - Is there Clinical Improvement Associated with Saline Injection for Dis...

#485 Is there Clinical Improvement Associated with Saline Injection for Discogenic Low Back Pain: Comparison of RCT Outcomes

Lumbar Therapies and Outcomes

Poster Presented by: N.W. Bae


H.W. Bae (1)
L.E. Kanim (1)
S. Thordarson (1)
N. Provenzano (1)
J. Kim (1)
T. Davis (1)

(1) Cedars-Sinai Spine Center, Department of Surgery, Div of Orthopaedics, Los Agneles, CA, United States


Background: Recently, several multicenter clinical trials studying the effect of biologic substances or cell-based injections on lumbar intervertebral disc repair are near completion. These studies included a placebo injection with saline as a control. Each of the experiments were randomized, double blinded, and prospective. Although the intent was to investigate novel treatment options, results from these trials have elucidated a possible saline effect.

Objectives: To evaluate outcomes from multiple intervertebral disc injection studies; all conducted at one institution, employing saline as a control injection. To calculate the clinically important difference needed to determine effectiveness of an intradiscal injection treatment.

Study Design: Comparison of results from four studies conducted at a single site that were prospective, randomized controlled, and double-blinded.

Methods: Standard across the studies (A, B, C, D), patients were only included if they had symptomatic disc disease at lumbar levels of L1 to L5/S1, had a positive provocative discography, and failed at least 3 months of nonoperative treatment. Patients ranged from 18 to 65 years of age, and were randomized into either the placebo (saline) or treatment (investigational substance) group. Self-administered questionnaires including the Visual Analog Scale for back/buttock pain (VAS) and the Oswestry Disability Index (ODI) for low back pain, along with surgeon administered physical exam were completed at pre-treatment (T0), and at least at 3, 6, 12 months post injection (T3, T6, T12).. Only study B utilized the Roland-Morris Disability Questionnaire instead of the Oswestry Questionnaire. For all studies, side effects and adverse events were systematically collected throughout as per clinical trial standard operating procedures at the site.

Results: Across the studies there was a statistically significant decrease in VAS pain for both the investigational treatment and saline injected patients ( p< 0.004, 3 mo; p< 0.007, 6 mo; p< 0.0001, 12 mo). VAS differences between saline and the investigational treatment were: T0-S:80.9 vs. I:71.4; 3mo-S:37.8 vs. I: 41.8 (NS); 6 mo-S:11.9 vs I: 45.3 p< 0.01. By 12 months, there was 58.4% less VAS pain for saline injected patients compared to 36.6% less pain for investigational treatment injected patients (S: 20.4 vs I:37.7 p< 0.01, ANOVA controlling for age and gender). There was an overall decrease in ODI and RM disability by 3 months and maintained to 12 month . ODI Improvement was greater for saline injected at 57.6% change than for investigational treatment injected patients (21.6% change). RM improvement was 82.7% for saline and 36.1% for investigation treatment injected patients at 12 months.

Limitations: Conservative care regimens of saline may offer patients a chance for some pain resolution and decreased disability. The 50% improvement observed for saline injected patients may also provide a means to define the MCID for injection type treatments. More patients, in addition to a longer follow-up period are needed to fully differentiate between a placebo effect and a saline effect. Sham procedures will be included in future injection studies.