Effects of adding a neurodynamic mobilization to motor control training in patients with lumbar radiculopathy due to disc herniation

The upshot

In people with lumbar disc herniation and radiculopathy, does adding neurodynamic (nerve) mobilization to motor control exercises produce better outcomes than motor control exercises alone?

Adding neurodynamic mobilization to motor control exercises reduced neuropathic symptoms and improved straight leg raise, but did not produce greater reductions in pain, disability, or pressure pain thresholds compared with motor control exercises alone. Both groups improved substantially, and the extra benefit of neural mobilization was small and probably not clinically meaningful.

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Primary study32 ParticipantsLimited evidence

Key points

No significant between-group difference in leg pain intensity or disability at any follow-up; both groups showed large within-group improvements (SMD greater than 1.25 for pain).
The neurodynamic group showed significantly greater reductions in neuropathic symptoms (S-LANNS) with large between-group effect sizes immediately after treatment (SMD 0.95) and at 2 months (SMD 0.75).
Straight leg raise improved more in the neurodynamic group (significant group-by-time interaction, P=0.01); between-group effect sizes were moderate after 4 sessions (SMD 0.55) and large after 8 sessions.
No between-group difference was found for pressure pain thresholds over the tibial or common peroneal nerve trunks; between-group SMD was small (0.14).
No adverse events were reported in either group; exercise program adherence was 96%.

How it was conducted

Design: Randomized parallel-group clinical trial (ClinicalTrials.gov NCT03620864), CONSORT-compliant
Participants: 32 adults aged 18-65 with MRI-confirmed L4-S1 disc herniation and lumbar radiculopathy (lower extremity pain for at least 3 months, positive straight leg raise 40-70 degrees), recruited from a hospital in Madrid, Spain, July-October 2018
Groups: Motor control exercises plus neurodynamic mobilization (n=16) vs. motor control exercises alone (n=16)
Intervention: 8 sessions over 4 weeks, twice weekly; motor control program (transversus abdominis and multifidus activation, progressed from supine to bridging and four-point kneeling); neurodynamic group also received sciatic nerve slider technique applied for 5 minutes before each session
Primary outcome: Lower extremity pain intensity (0-10 Numeric Pain Rating Scale)
Follow-up: Baseline, after 4 sessions, after 8 sessions, and 2-month follow-up; assessor blinded to group allocation

What they found

No significant group-by-time interaction for lower extremity pain intensity (F=0.269; P=0.05; partial eta-squared 0.043); between-group SMD was small (0.20) while within-group SMD was large for both groups (greater than 1.25).
Significant group-by-time interaction for S-LANNS neuropathic symptom score (P=0.001; partial eta-squared 0.373); the neurodynamic group showed greater reductions; between-group SMD was large immediately after treatment (SMD 0.95) and at 2 months (SMD 0.75).
No significant group-by-time interaction for Roland Morris Disability Questionnaire (F=2.x; P=0.10; partial eta-squared 0.023); between-group SMD was small (0.18) while within-group SMD was large for both groups (greater than 1.15).
Significant group-by-time interaction for straight leg raise (P=0.01; partial eta-squared 0.220); neurodynamic group improved more; between-group effect sizes were moderate after 4 sessions (SMD 0.55), large after 8 sessions, and large at 2-month follow-up (SMD 0.x); between-groups difference at 2-month follow-up was 8.8 degrees, surpassing the minimal detectable difference reported by Neto et al. but not the 16-degree cut-off reported by Dixon and Keating.
No significant group-by-time interaction for tibial nerve PPT (P=0.026) or common peroneal nerve PPT (F=1.658; P=0.426; partial eta-squared 0.046); between-group SMD was small (0.14) while within-group SMD was large for both groups (greater than 1.04).
Straight leg raise at baseline: motor control group 53.2 plus or minus 10.0 degrees; neurodynamic group 55.2 plus or minus 6.5 degrees.
Baseline mean leg pain: motor control group 6.0 plus or minus 1.4 (NPRS); neurodynamic group 5.9 plus or minus 1.4 (NPRS).
Baseline S-LANNS: motor control group 12.0 plus or minus 1.3; neurodynamic group 12.0 plus or minus 1.1.

Limitations

All interventions delivered by a single therapist at one location, limiting generalizability.
Small sample size (n=32 total); possibly underpowered to detect between-group differences on some secondary outcomes.
Disc herniations restricted to L4-S1 level only; findings may not apply to other lumbar levels or different herniation magnitudes.
No control group (sham or no treatment), and only a 2-month follow-up; long-term effects unknown.

Why it matters

For patients: Patients with lumbar disc herniation and nerve pain can expect meaningful improvement from a motor control exercise program, but adding nerve mobilization is unlikely to reduce their pain or disability noticeably more.
For clinicians: Neurodynamic mobilization added to motor control exercises may help reduce neuropathic symptom scores and improve straight leg raise range modestly, but the difference over exercise alone was small and of uncertain clinical relevance for pain and function outcomes.
For readers: This small single-centre trial provides preliminary evidence that combined therapy offers only marginal neural benefits over exercise alone; larger trials with longer follow-up are needed before recommending neurodynamic mobilization as a routine add-on.

Source

doi:10.1097/phm.0000000000001295

Read the original paper

Clinically assessing this area? See the lumbar spine & low back special tests.