The efficacy of cervical lordosis rehabilitation for nerve root function and pain in cervical spondylotic radiculopathy: a randomized trial with 2-year follow-up

Key points

1. 01Three-point bending cervical extension traction increased cervical lordosis by a mean of 7.5 degrees after 10 weeks, sustained at 2 years
2. 02Study group pain scores continued to improve to 2 years (mean 1.71 on NRS), while control group pain worsened after treatment ended (mean 4.3 at 2 years)
3. 03Nerve root function (DSSEPs) improved in both groups at 10 weeks, but only the traction group maintained improvements at 3 months and 2 years
4. 04Greater cervical lordosis correlated inversely with pain (r = -0.49 at baseline; r = -0.6 at 2-year follow-up in traction group)
5. 05At 2-year follow-up, 9 of 15 control patients were using additional medications or therapies versus only 2 of 15 in the traction group

How it was conducted

Design

Prospective investigator-blinded parallel-group randomized controlled trial with 2-year follow-up

Participants

30 adults aged 40-50 with chronic lower cervical spondylotic radiculopathy (C5-C6 and/or C6-C7) and cervical lordosis less than 20 degrees

Groups

Study group (n=15): cervical extension traction plus stretching and infrared radiation; Control group (n=15): stretching and infrared radiation only

Treatment duration

3 sessions per week for 10 weeks (30 sessions total), followed by 3-month and 2-year follow-up assessments

Primary outcomes

Cervical lordosis (ARA C2-C7 on lateral radiograph) and dermatomal somatosensory evoked potential (DSSEP) amplitude at C6, C7, C8

Secondary outcome

Numerical pain rating scale (NPRS, 0-10)

What they found

• Cervical lordosis (ARA C2-C7): study group increased from 14.3 +/- 4.1 degrees at baseline to 20.87 +/- 3 degrees at 10 weeks, 19.5 +/- 3.2 at 3 months, and 18.8 +/- 2.1 at 2 years (p < 0.001 for group x time interaction); control group showed no significant change (14.6 to 14.7 to 14.1 to 12.3 degrees)
• Pain (NRS): study group improved from 5.26 +/- 0.96 at baseline to 3.2 +/- 1.26 at 10 weeks, 2.8 +/- 1.27 at 3 months, and 1.71 +/- 1.2 at 2 years; control group improved to 3.9 at 10 weeks then worsened to 4.6 at 3 months and 4.3 at 2 years; between-group difference p < 0.0001 at all follow-ups
• DSSEP C6 amplitude: study group 0.41 +/- 0.1 uV at baseline to 0.80 +/- 0.19 at 10 weeks, 0.79 +/- 0.11 at 3 months, 0.82 +/- 0.14 at 2 years; control group 0.42 +/- 0.2 to 0.56 +/- 0.15 then regressed to 0.40 +/- 0.15 and 0.42 +/- 0.17; between-group p < 0.001
• DSSEP C7 amplitude: study group 0.4 +/- 0.1 uV to 1.18 +/- 0.33 at 10 weeks, 1.0 +/- 0.37 at 3 months, 1.1 +/- 0.37 at 2 years; control group 0.69 +/- 0.2 to 0.7 +/- 0.18 then declined to 0.52 +/- 0.21 and 0.51 +/- 0.18; between-group p < 0.001
• DSSEP C8 amplitude: study group 0.6 +/- 0.2 uV to 1.3 +/- 0.5 at 10 weeks, 1.4 +/- 0.6 at 3 months, 1.5 +/- 0.6 at 2 years; control group 0.8 +/- 0.2 to 0.9 +/- 0.3 then regressed to 0.7 +/- 0.3 and 0.7 +/- 0.2; between-group p = 0.005 at 10 weeks, p < 0.001 at 3 months and 2 years
• Baseline correlation between cervical lordosis and pain for both groups combined: r = -0.49, p = 0.005; maintained at 2-year follow-up only in traction group: r = -0.6, p = 0.01
• Baseline correlation between cervical lordosis and DSSEP amplitude: C6 r = 0.65, C7 r = 0.57, C8 r = 0.8, all p < 0.0001

Limitations

• Small sample size of 15 per group, just above the minimum required for statistical significance; the 2-year control group had only 12 participants, falling below the 14 needed for robust claims
• Lack of investigator blinding (described as investigator-blinded but limitations section acknowledges this as a concern)
• Convenient rather than random population sample, limiting generalizability
• Retrospective trial registration and no longer than 2-year follow-up; longer follow-up needed to understand durability of curve correction

Why it matters

For patients

People with chronic neck radiculopathy and reduced cervical curve may experience sustained pain relief and nerve function improvement if their treatment includes curve-correcting traction, rather than just stretching exercises alone.

For clinicians

Adding three-point bending cervical extension traction to a standard physiotherapy program produced objectively measurable and durable improvements in nerve root conduction and pain in hypolordotic CSR patients, suggesting sagittal alignment correction should be considered alongside conventional conservative care.

For readers

This small RCT provides preliminary evidence that restoring cervical lordosis is a clinically meaningful treatment target in spondylotic radiculopathy, but larger trials are needed before this approach can be broadly recommended.