Monthly Archives: July 2012

Study confirms turned head position worsens whiplash

Turned-head position is often associated with more severe whiplash symptoms. This has prompted a number of biomechanical studies using human cadaveric necks to test whether head position produces measurable changes in whiplash injury. These tests have been limited to certain flexion/extension moments and did not examine the effects of posterior shear and axial compression loading, according to researchers Sigmund et al.  That leaves remaining questions of how different axial forces impact ligament loading. Sigmund et al. set out to investigate how a head-turned position interacts with multiaxial loading to alter injury to the facet capsule.

Using vertebral bodies donated form female cadavers, researchers created a simulation of  a rear-end collision with turned-head position. They applied axial pretorques, axial compression preloads, and quasi-static shear load to the vertebral bodies to simulate the kinematics of whiplash injury. Three dimensional markers were placed on the vertebral bodies to help researchers measures strains on the ligaments during loading. The effects of the varying forces were calculated using repeated-measures analyses of variance. They discovered that:

  • Axial rotation doubled maximum peak strain. In other words, a turned-head position doubled the strain placed on facet capsules. Peak capsule strain with pretorque was 17% ±6%.
  • Axial pretorque influenced peak strain more than axial compression or posterior shear loading.
  • The effect of having a head-turned position was similar to effects of partial ligament failure found in previous studies.
  • Head rotations to the right produced strain on the right facet capsule. Peak strains were higher when pretorque force was applied towards the capsule rather than away (reaching 34% ±18% percent).

These findings confirm that turned-head posture increases strain placed on the facet capsules. This provides further explanation for the more severe symptoms experienced by whiplash patients whose heads were turned during the collision.

Reference

Siegmund G, Davis M, Quinn K, et al. Head-turned postures increase the  risk of cervical facet capsule injury during whiplash. Spine 2007; 33(5): 1643-1649.

Diabetes medication boosts brain cell growth

The popular diabetes medication metformin has recently been shown to have an unexpected side effect. It apparently encourages the growth of neurons within the brain. A new study showed that these neural effects made mice smarter when they were given metformin.

This new findings  is promising for those with brain injuries, as it is an important step towards therapies that repair the brain by spurring neurons into action. The study’s lead author, Freda Miller of the University of Toronto’s Hospital for Sick Children, says that the metformin activates pathways in neural stem cells, encouraging brain repair.

In the study, mice taking metformin showed an increase in new neurons, and were better able to navigate a maze test. While it’s too early to tell whether the drug might be a brain-booster to those who are already taking it, there is already evidence that it may benefit patients with Alzheimer’s disease. These improvements had previously been attributed to better control of the patient’s diabetes, but it now appears that the benefit may be caused by metformin’s brain repairing benefits.

According to Miller, researchers now hope to test metformin’s ability to repair the brains of those with brain injuries caused by trauma or radiation therapy.

Reference

Wang J, Gallagher D, DeVito LM, et al. Metformin activates an atypical PKC-CBP pathway to promote neurogenesis and enhance spatial memory formation. Cell Stem Cell 2012;11(1): 23-35.

Temporomandibular joint disorder linked to tinnitus

Tinnitus is the perception of sound in the absence of any sound source outside the ear. Commonly described as “ringing in the ears,” this condition can have a wide variety of causes. For example, it frequently presents along with whiplash injuries following an auto collision.

Because of the wide variety of tinnitus cases, researchers have proposed subtyping the different forms as a way to facilitate diagnosis and treatment. However, it has not yet been determined which criteria are useful for creating subtypes. In this study, researchers differentiated patients according to whether they had also complained of temporomandibular joint (TMJ) disorder symptoms in order to determine whether TMJ complaints could be criteria for defining a tinnitus subtype.

The study involved 1204 patients from the Tinnitus Research Initiative (TRI) Database. 22% of the patients had complained of TMJ symptoms, while the others had not. Researchers found that patients complaining of TMJ symptoms along with tinnitus tended to be younger, with a lower age of tinnitus onset, and were more likely to be female. However, the groups did not differ significantly in duration of tinnitus, onset related events (such as whiplash), duration of tinnitus duration, ratings of loudness, and other factors.

Patients with both TMJ and tinnitus symptoms were more likely to be able to mask the tinnitus by playing sounds or music, or by somatic maneuvers (working their jaw). This finding is considered relevant because it shows that TMJ complaints affected the patients’ ability to control tinnitus symptoms, suggesting that specific therapeutic treatments may work better for TMJ patients than for other patients.

Reference

 Veronika V, et al. Temporomandibular Joint Disorder Complaints in Tinnitus: Further Hints for a Putative Tinnitus Subtype. PLoS One 2012; 7 (6):e38887.

 

Postconcussion symptoms in patients with chronic injury-related pain

Postconcussion symptoms such as headaches, irritability, impaired memory, fatigue, and dizziness are commonly reported by patients who have experienced mild traumatic brain injuries. It is believed that evaluating postconcussion symptoms (PCS) following MTBIs could have a diagnostic value, although it is not known if PCS are specifically caused by MTBI.

New research attempted to explore the relationship between PCS, pain, and psychological factors using questionnaires involving symptoms, pain intensity, depression, anxiety, and posttraumatic stress. The aim of the study was the determine the frequency of PCS symptoms in patients with chronic pain caused by an injury. Researchers also sought to study the relationships between pain intensity, posttraumatic stress, depression, and PCS symptoms.

The study involved 86 patients of the Pain Rehabilitation Clinic at Umeå University Hospital in Sweden. The causes of patients’ injuries included sports, assaults, falls, work-related injuries, whiplash, and nonwhiplash traffic collision injuries. In all cases, it had been at least one year since the initial injury.

This study found that patients with injury-related pain reported long-term postconcussion symptoms. Fatigue was the most commonly-reported symptom with 90.7% of participants reporting they experienced fatigue. More than 60% of patients also experienced headache, impaired memory, sleep disturbance, and poor concentration. The researchers also found significant relationships between PCS and depression, anxiety, and posttraumatic stress.

These results serve as a reminder that patients with mild traumatic brain injuries should be evaluated for physical symptoms as well as depression, posttraumatic stress, and other factors.

Reference

Stålnacke BM. Postconcussion Symptoms in patients with injury-related chronic pain. Rehabil Res Pract 2012; v2012:doi 10.1155/2012/528265.

 

Pain hypersensitivity in whiplash patients

New research suggests that women with whiplash injuries experience widespread hypersensitivity to pain.

The research involved 25 women with chronic whiplash and 10 healthy women. Each participant was evaluated using pressure cuffs around the arm and the leg, along with hypertonic saline infusion. The cuffs were inflated, and patients’ pain intensity was monitored to determine the thresholds of pain detection and pain tolerance.

The Swedish researchers who conducted the study found that pressure pain thresholds were lower in patients with chronic whiplash when compared  to the control group. Further, the results indicated that patients with chronic whiplash were more likely to experience hyperalgesia, or an exaggerated sense of pain.

Another recent study suggests that pain sensitivity and trigger points in whiplash patients could worsen with time.

Resource

Lemming D, Graven-Nielsen T, Sörensen J, Arendt-Nielsen L, Gerdle B. Widespread pain hypersensitivity and facilitated temporal summation of deep tissue pain in whiplash associated disorder: An explorative study of women. J Rehabil Med 2012; 44(8):648-57.

More pain sensitivity, more trigger points in whiplash patients

The relationship between active trigger points and sensitization in patients with acute whiplash is not fully understood. New research suggests that the higher the number of active trigger points, the greater the pain sensitization experienced by these patients.

Researchers set out to investigate the prevalence of trigger points (or TrPs) in 20 patients with acute whiplash compared to 20 healthy patients. They wanted to determine whether widespread hypersensitivity to pressure or reduced range of motion were related to the presence of trigger points in people with whiplash-associated disorders.

Researchers found that patients with acute whiplash had a higher number of TrPs. In fact, the number of active trigger points increased with higher neck pain intensity, as well as a longer period since the initial whiplash injury. Injured patients also had lower pressure pain threshold (PPT) scores and a reduced range of motion when compared to control patients. The greater the number of active pressure points, the lower the range of motion.

This study adds to previous research by showing that in patients with acute whiplash, the number of active TrPs is related to the number of days since the initial injury, higher intensity of neck pain, higher pressure pain sensitivity, and reduced range of motion. The study suggests that pain sensitization and presence of trigger points progressively worsens with time.Receiving early whiplash treatment could prevent increasing pain.

Resources

Fernández-Pérez AM, et al. Muscle trigger points, pressure pain threshold, and cervical range of motion in patients with high level of disability related to acute whiplash injury. J Orthop Sports Phys Ther. 2012;42(7):634-41.

 

Ligament injury in whiplash patients

Recent research reveals new information about the microtrauma whiplash produces in the ligaments of the neck.  A new study from Ulbrich et al (2011) suggests that the transverse ligament is detrimentally altered during whiplash injury.1

The transverse ligament is a strong band stretching across the atlas (C1), or the first vertebra of the cervical spine. As part of the cruciate ligament, the transverse ligament work with vertical fibers and other ligaments to stabilize the neck.

Experimental data of simulated rear-end crashes showed that the craniocervical junction is the most vulnerable region in rear-end collisions.2 Force applied to the craniocervical junction may therefore have more pronounced consequences for the ligaments and muscles in this region.

Studies of the effects of whiplash on  the craniocervical junction have focused on damage to the alar ligaments. 3-4 Fewer studies have tested whether whiplash damages the transverse ligament.

Ulbrich et al (2011) studied how whiplash injury influences the transverse ligament by evaluating patients within the first 48 hours after receiving the injury. Using a variety of MRI imaging techniques they confirmed that whiplash affects the transverse ligament with the following results:

  • STIR and VIBE imaging showed significant alterations of the transverse ligament.
  • Male whiplash patients had thicker transverse ligaments than healthy participants. Researchers speculated that this is likely due to posttraumatic swelling. Interestingly, this increased thickness was not observed in female patients.
  • Significant signal alterations of the transverse ligament were observed on both un-enhanced STIR and VIBE imaging. Researchers explained that this possibly relates to “stretching and microtrauma to collagen fibers of the transverse ligament with edema.” These changes were less pronounced however when researchers injected a contrast agent, a substance used to enhance the contrast of structures or fluids in MRI imaging.

Given the minimal changes of the transverse ligament detected in MRI imaging, the authors argued that “upper neck MRI is of limited value in the initial examination of patients with WAD grade I or II and cannot be recommended for routine use in this setting.” Instead MRI imaging of this region may be better suited for studying “injury-related changes.” Despite that only small changes in the transverse ligament were detected, gaining a better understanding of the mircotrauma ligaments undergo could improve doctors’ understanding and treatment of whiplash-associated disorders. Researchers suggested that further research could continue to elucidate the subtle but objective posttraumatic effects of whiplash.

References

1.Ulbrich, EJ, et al. Alterations of the Transverse Ligament: An MRI study comparing

patients with acute whiplash and matched control subjects. AJR Am J Roentgenol 2011;197(4):961-7.

2. Ivancic PC, Panjabi MM. Cervical spine loads and intervertebral motions during whiplash. Traffic Inj Prev 2006; 7:389–399

3. Krakenes J, et al. MRI assessment of the alar ligaments in the late stage of whiplash injury: a study of structural abnormalities and observer agreement.

Neuroradiology 2002; 44:617–624

4. Krakenes J, Kaale B. Magnetic resonance imaging assessment of craniovertebral ligaments and membranes after whiplash trauma. Spine 2006; 31:2820–2826

Nintendo Wii-like device detects brain bleeds

Detecting a serious brain bleed could be as simple as operating a Nintendo Wii remote. A new hand-held device, called the InfraScanner, is similar to a Nintendo Wii remote with its look, portability, and rechargeable batteries. The device can be used to diagnose brain bleeds from explosive blasts, sports accidents or other incidents.

The scanner uses infrared light to measure eight spots in the brain. Any asymmetry detected could be a sign of a brain bleed. A part of the brain with a bleed contains up to ten times more hemoglobin than normal. The scanner senses these high concentrations of hemoglobin to identify the affected area of the brain. Fiber optics allow the scanner to get a reading through the hair so victims can avoid shaving their heads.

The portability of the device is appealing to the military which has been searching for methods of improving treatment of combat-related concussions. Brain injuries have become a heated issue as more soldiers return with “the signature wounds of war.” The Marine Corps Systems Command commissioned InfraScan Inc. to create a more heavy-duty version of the device for combat use. The scanner could be used to prioritize injuries in a major blast or heavy causality situation.

At a whopping $18,000 a piece, you aren’t likely to see the scanner cropping up in doctors’ offices anytime soon, but the device could assist emergency respondents in quickly identifying some serious brain injuries.

Reference

Harkins, Gina. Hand-held scanner can detect brain injuries. MarineCorps Times. June 26, 2012. Accessed July 10, 2012. http://www.marinecorpstimes.com/news/2012/06/marine-portable-brain-scanner-bleeds-traumatic-injuries-062612w/.

Photo by InfraScan Inc.