Spinal Manipulation vs. Nerve Root Injection for MRI-Confirmed Lumbar Disc Herniation: Prospective Cohort

Research Review By Dr. Kent Stuber© November 2013

Study Title:

Symptomatic magnetic resonance imaging-confirmed lumbar disk herniation patients: a comparative effectiveness prospective observational study of 2 age- and sex-matched cohorts treated with either high-velocity, low-amplitude spinal manipulative therapy or imaging-guided lumbar nerve root injections

Authors: Peterson CK, Leeman S, Lechmann M, et al.

Author's Affiliations: Orthopaedic University Hospital Balgrist and the University of Zurich, Switzerland.

Publication Information: Journal of Manipulative & Physiological Therapeutics 2013; 36(4): 218-225.

Background Information:

Lumbar disc herniations (LDH) represent a common and disabling low back injury that is often associated with concurrent leg pain (sciatica). The natural history of sciatica in LDH cases trends toward resolution within two to three months. However, treatment can potentially help reduce that span and the impact during that period. Still, the most effective treatment for LDH remains largely unknown to date, although it is generally agreed that a course of conservative treatment should be undertaken before surgery is considered.

This study compared two commonly employed interventions for patients with LDH – spinal manipulative therapy (SMT) and nerve root injections, in terms of their effects on pain and perceived symptomatic improvement in patients with MRI confirmed LDHs.

Pertinent Results:

The average age of the 102 included patients was 47.6 years; 62.7% were male. The injection group had a significantly higher average initial Numerical Rating Scale (NRS) score when compared with the SMT group. The average number of SMT treatments was 11.2 (ranging from 5 to 20). Only 1 SMT patient reported being worse after treatment compared with 3 injection patients. No SMT patients required surgery during the study period, while 3 injection patients received a second injection and 3 had surgery. In the SMT group, 76.5% of patients were “improved” (Odds Ratio = 1.93, 95% Confidence Interval of 0.82-4.56), while 62.7% of the injection patients were “improved” (OR = 0.52, 95% CI: 0.22-1.23). There was no statistically significant difference between groups in terms of the proportion reporting clinically important improvements. The SMT and injection groups each had significant decreases in NRS scores at one month, with an average pain reduction of 60% in the SMT group and 53% (NRS score) in the injection group. Between groups at one month there were no significant differences in NRS scores, Patient Global Impression of Change (PGIC, a 7 point scale) scores or NRS change scores. The average cost in the SMT group was 533.8 Swiss Francs, while the average cost in the injection group was a total of 697 Swiss Francs.

Clinical Application & Conclusions:

While there were no significant differences between groups, both nerve root injections and SMT produced statistically significant and clinically important improvements in pain and perceived change in symptoms after 1 month of treatment for patients with symptomatic MRI-proven LDH. The average cost of SMT treatment was slightly lower than nerve root injections. The patients averaged 11 treatments over the course of a month. No mention was made of the use of other treatments during the study period including or excluding exercise therapies, electrical modalities, or analgesic or other medications.

From a clinical standpoint, most clinicians who utilize SMT on patients with LDH can be reassured that their treatment is at least as effective and potentially more cost effective when compared with nerve root injections for this condition. Previous research (see Additional Reference 1 below) has indicated the overwhelming safety of SMT for patients with LDH. Another interesting take home point is that the authors employed certain types of manipulations for certain disc herniation locations and this may be advisable for manual therapists to consider when seeing patients with LDH, particularly in light of the largely positive results in this study, and how few of the SMT group patients were “worse” after 1 month of treatment (only 1, as mentioned above). As a reminder, patients with intraforaminal LDHs (as noted on MRI) received a modified push adjustment with a kick, whereas patients with paramedian LDHs receive a pull adjustment with a kick.

Study Methods:

This was a prospective cohort study of patients with MRI-proven and clinically correlated LDH that compared the effectiveness of the two treatments: manual SMT and imaging-guided nerve root injections. Data was obtained from two separate databases, one for each treatment group respectively. From each group, 51 age and gender matched patients were selected for analysis by a blinded researcher (for a total of 102 patients). Nerve root injection patients had not received SMT and vice-versa. Manual Diversified style lumbar SMT was employed, but the type of adjustment utilized depended on the location of the LDH: patients with intraforaminal LDHs (as noted on MRI) received a modified push adjustment with a kick, whereas patients with paramedian LDHs receive a pull adjustment with a kick. The nerve root injection group received contrast fluoroscopy- or CT-fluoroscopy guided injections of Kenacort and Ropivacaine.

Baseline Numerical Pain Rating Scales (NRS) values were obtained, and after one-month of treatment a telephone interview obtained NRS values and Patient Global Impression of Change (PGIC, a seven-point scale), which was considered the primary outcome measure. The clinically meaningful change for NRS scores was deemed to be 30%. For the PGIC, only responses of ‘much better’ (1 on the scale) and ‘better’ (2 on the scale) were taken to mean “improvement” of a patient’s condition, whereas scores of 5 through 7 (‘slightly worse’, ‘worse’, ‘much worse’ respectively) would lead to the patient being categorized as “worse”. Student t tests were used to compare NRS scores and NRS change scores within groups. Unpaired t tests were used to compare between groups for NRS and NRS change scores. The Mann-Whitney U test was used to compare group average PGIC scores, while the chi square test was used to compare the groups for “improvement”. Odds ratios with 95% CIs were calculated as were average direct procedure costs for each treatment.

Study Strengths/Weaknesses:

The biggest weakness of this study was that it was not actually a randomized controlled trial. As such, patient preference and other confounding factors may have influenced the results. It was a well-designed and well-executed cohort trial nonetheless, even though the sample sizes were relatively small. This study should help provide the impetus for future RCTs on patients with LDH to include an SMT arm. The authors did have issues with the injection group database as it did not contain as much demographic information, making additional group matching (such as chronicity of condition) beyond age and gender not feasible. The injection group had significantly higher initial pain levels, indicating that there may be differences between the two groups of patients, particularly as they had already self-selected their treatments. The authors also mention that telephone administered outcome measures often have more positive responses when compared with postal questionnaires.

An additional weakness is that only 1-month outcome measurement took place and there was no additional follow-up. Having additional outcome data such as Oswestry disability questionnaire scores or other indications of disability or quality of life would have been informative.

The only treatments utilized in this study were the nerve root injections or SMT. There were no additional interventions that were included for either group such as home exercises, over the counter medications, patient education, and so on. The study could have been more clinically applicable (or pragmatic) if one or more such treatments were included/allowed. However, as mentioned, the study did provide direction as to how they decided on the type of SMT to administer based on LDH location, as well as reporting an average of 11 SMT treatments over the course of a month. Both of these factors could assist practitioners with treatment planning for patients for LDH.

Finally, all of the patients had MRI-confirmed LDH, and frequently in primary care practice clinicians will have to proceed with treatment for LDH patients based on history and physical examination findings, due to waiting time constraints for MRI (at least in Canada). Again, that could represent a difference between the study population and those seen in practice.

Additional References:

Oiphant D. Safety of spinal manipulation in the treatment of lumbar disc herniations: a systematic review and risk assessment. J Manipulative Physiol Ther 2004; 27:197-210. Leininger B, Bronfort G, Evans R, Reiter T. Spinal manipulation or mobilization for radiculopathy: a systematic review. Phys Med Rehabil Clin N Am 2011; 22:105-25.