Research Review by Dr. Michael Haneline©


Nov. 2008

Study Title:

Comparison of 3 physical therapy modalities for acute pain in lumbar disc herniation measured by clinical evaluation and magnetic resonance imaging


Unlu Z et al.

Authors’ Affiliations:Department of Physical Medicine and Rehabilitation, Celal Bayar University, Manisa, Turkey.

Publication Information:

Journal of Manipulative and Physiological Therapeutics 2008; 31: 191-198.


Lumbar disc herniation (LDH) is a common cause of lower back pain that can frequently be managed by non-operative care, including physical therapy modalities. However, there is little evidence in support of the use of physical therapy modalities for LDH and the Agency for Health Care Policy and Research guidelines even discourage practitioners from using them.

The evidence is conflicting as to the effectiveness of lumbar traction for LDH, which has been taken to mean in some guidelines that traction is ineffective for this condition. As for ultrasound and laser for the treatment of LDH, no data is available. In spite of the evidence, however, practitioners use traction and ultrasound extensively in the treatment of LDH. The authors suggested this discrepancy is probably because of the practitioners’ positive experiences using these modalities.

The examination of choice for diagnosing LDH is magnetic resonance imaging (MRI), yet the authors could find no studies that evaluated the efficacy of physical therapy modalities in patients with LDH using MRI. Accordingly, the purpose of this study was to compare the effect of several non-surgical treatment methods for LDH: traction, ultrasound, and low-power laser (LPL). Several commonly used subjective indices were used as outcome measures, as well as MRI, which was used to compare the size of the LDH pre- and post-treatment.

Sixty sequentially presenting patients with confirmed LDH were recruited from a university clinic and were randomized into 3 groups of 20 subjects each. Patients were treated 5 days per week for 3 weeks, totaling 15 sessions. Interventions were as follows:
  1. Lumbar traction (intermittent motorized):applied for 15 minutes per session with force applied for 30 seconds, then rest for 10 seconds. The force was set to patient tolerance, ranging from 35% to 50% of body weight. Patients were positioned supine with their knee and hips flexed to 90 degrees.
  2. Ultrasound:was performed at an intensity of 1.5 W/cm2 in continuous mode, applied over the posterior lumbar region bilaterally for 8 minutes.
  3. Low-power laser:was applied over both sides of the disc spaces where the herniation was detected on MRI for 4 minutes at each point. A continuous form of energy was delivered and the power output was 50 mV and a wavelength of 830 nm. The diameter of the laser beam was 1 mm. The dose at each point was 1 J.
Outcome measures:
  • Physical examination:lumbar ROM, tenderness on palpation of paravertebral muscles, straight-leg raise test (SLRT), femoral stretch test in patients with femoral neuralgia, neurological (reflexes and strength)
  • Subjective measures:visual analog scale (VAS), with 0 representing no pain to 100 unbearable pain, Roland Disability Questionnaire (RDQ), Modified Oswestry Disability Questionnaire (MODQ)
  • MRI
Pertinent results of this study:
  • Examination findings were significantly improved from baseline values for each outcome measure, except the Schober test.
  • There were few significant differences on examination findings between the 3 groups at the follow-up evaluations.
  • Pain and disability scores were significantly improved between baseline and follow-up evaluations, though there were no significant differences between the 3 treatment groups.
  • LDH size on MRI was reduced significantly subsequent to treatment in each group, but again, there were no differences between the groups.
  • There was no correlation between physical examination findings, pain, and disability scores when compared to change in LDH size.

Conclusions & Practical Application:

This study was thought to be the first to compare the effectiveness of traction, laser, and ultrasound in the treatment of acute LDHs. The study generally pointed to no significant differences between the groups, although each group showed significant improvements in examination findings, LDH size, as well as subjective findings. The authors were therefore able to conclude that traction, laser, and ultrasound treatments were equally effective in the treatment of acute herniated lumbar disc syndrome.

The authors argued that previous studies that have been critical of the use of physical therapy modalities in the treatment of LDH were poorly designed. That being stated, several studies have investigated traction as a therapy for patients with sciatica, finding it to be better than a corset, bed rest, isometric abdominal exercise, heat, hot-pack massage, and mobilization. Laser and ultrasound have not been investigated with regard to this condition.

In spite of the evidence maligning its use, mechanical traction is preferred by many physical therapists for the treatment of acute sciatica. The same is true for ultrasound and TENS(1). The results of the current study support the use of traction, laser, and ultrasound in the treatment of LDH, which may influence the recommendations of future guidelines.

Comment: The major limitation of this study is the lack of a control group assigned to receive a placebo form of traction, ultrasound or laser. Another comparison that could have increased confidence in the study’s findings would be the inclusion of another group that received no treatment (waiting list). Studies that do not include these kinds of comparisons are subject to numerous biases (e.g., natural progression of the condition, regression to the mean, placebo effect, etc.). Consequently, these non-specific components of treatment may have been the real reason patients improved in this study rather than the interventions that were used.

Additional References:

  1. Li CL, Bombardier C. Physical therapy management of low back pain: an exploratory survey of therapist approaches. Phys Ther 2001;81:1018-28.