Chiropractic + Naturopathic Doctor

Research Review Corner: December 2010

Shawn Thistle   

Features Research

In early 2011, Research Review Service will be publishing a bonus update containing brief summaries of top research that has not been reviewed in full.   Below are some brief excerpts from this document.

In early 2011, Research Review Service will be publishing a bonus update containing brief summaries of top research that has not been reviewed in full.  Below are some brief excerpts from this document.

Study 1: Previous back injury and discdegeneration 

Publication Information:  Hancock MJ et al. The Role of Back Injury or Trauma in Lumbar Disc Degeneration: An Exposure-Discordant Twin Study. Spine 2010; 35(21): 1925.1929.

This study aimed to investigate the effect of injury on lumbar disc degeneration in monozygotic twins with discordant exposures to previous injury/trauma to the lumbar spine.  Disc degeneration is considered a primary source of low back pain, yet determinants of disc degeneration other than genotype have not been identified. One possible important determinant of disc degeneration that has undergone limited investigation is previous back injury. The authors compared disc degeneration between 37 male monozygotic twin pairs with discordant exposures to recalled previous injury/trauma to the lumbar spine. Data on injury history were obtained through an extensive structured interview. Disc degeneration was assessed using quantitative measures of disc height and disc signal intensity on advanced imaging.


Disc degeneration did not differ between twins who reported previous back injury and their uninjured twins. This finding was consistent for both disc height and disc signal intensity regardless of whether mean scores or greatest difference at any one lumbar level was used in the analysis. There was also no evidence that a greater period since an injury resulted in greater twin differences in disc degeneration.


The current study suggests that back injury based on patient report is not an important predictor of future disc degeneration. In recent years, beliefs regarding the determinants of disc degeneration have changed dramatically. It was previously thought that the primary determinants of disc degeneration included age, gender, cigarette smoking, exposure to vehicular vibration and, in particular, occupational physical loading. More recently, it has been demonstrated that most of these factors have, at most, a relatively minor influence on disc degeneration. In fact, routine loading may actually have some benefits for the lumbar discs in terms of slowing desiccation.  Even though genetic factors seem to be the most consistent influence on disc degeneration, there is still much to be learned. 


Study #2: Age and lumbar ROM

Publication Information:  Intolo P et al. The effect of age on lumbar range of motion: A systematic review. Manual Therapy 2009; 14:596-604.


This systematic review examined the evidence on the effect of age on lumbar ROM in healthy subjects.


Sixteen studies met inclusion criteria and were analyzed by the authors.  These studies suggest that age-related reductions occur in flexion (more in males), extension and lateral flexion particularly from 40 to50 and after 60 years of age. There was very little age effect on lumbar rotation.  Overall, there is strong evidence for a non-linear age-related reduction in lumbar sagittal and coronal ROM after 40 years of age that also appears to be asymmetric in the coronal plane. These factors should be considered during the evaluation of spinal ROM in patients who present with lumbar disorders.


The results of this study remind clinicians to consider the age of their patients when assessing lumbar ROM, or using it as an outcome during the course of treatment.  It should be noted that this study could not elucidate whether decreases in lumbar ROM are inevitable or irreversible, or make inferences on other biomechanical characteristics of the aging spine.   


Study #3: Migraine headache and CROM in women

Publication Information: Belivaqua-Grossi D et al. Cervical mobility in women with migraine. Headache 2009; 49: 726-731.


The aim of this study was to contrast the cervical range of motion (CROM) in women with episodic migraine (EM), transformed migraine (TM), and migraine-free controls (45 total subjects, 15 in each group). It is well known that migraineurs often complain about neck pain. Furthermore, neck problems can worsen the headaches in individuals with migraine. Individuals with neck pain usually have reduced CROM. To date, there is little research assessing the CROM in migraineurs.


Compared with controls, individuals with TM had numerically inferior CROM in all parameters, and significant reduction in extension, left lateral flexion and right rotation.  Compared with individuals with migraine, the TM group presented significantly reduced mobility only for extension.  Migraineurs also had numerically inferior ROM, contrasted to controls, in five of the six parameters, although significance was seen just for right rotation. There was no correlation between cervical mobility and migraine parameters. The CROM was not reduced for the symptomatic side of migraine, in cases of unilateral pain.


Although this was a small study, the results suggest that women with episodic or transformed migraine have reduced cervical ROM compared to controls.  Since many migraine patients also report neck pain, and a common goal of manual therapists is to restore ‘normal’ ROM, future research will hopefully examine if there is cause and effect relationship between ROM and migraine that we could positively influence with treatment.

Shawn Thistle, BKin (Hons), DC, CSCS – Dr. Shawn Thistle is the founder and president of Research Review 
Service Inc., an online, subscription-based service designed to help busy practitioners to integrate current, relevant scientific evidence into  their practice. Shawn graduated from CMCC and holds an Honours Degree in Kinesiology from McMaster University. He also holds a certificate in Contemporary Medical Acupuncture from McMaster University, and is a Certified Active Release Techniques (ART®) Provider.  For more information about the Research Review Service, visit 

Print this page


Stories continue below