Chiropractic Research in Review
The following abstracts come from two sources: the Journal of Manipulative and Physiological Therapeutics (published nine times annually) and the Journal of Chiropractic Medicine (published quarterly).Abstracts are reprinted with permission. The National University of Health Sciences, owner of the journals, upholds their compliance with the highest publication standards, which expressly support editorial freedom and best publication practices. Access complete abstracts from each issue of JMPT and JCM online. For background information on National's three peer-reviewed journals (Journal of Chiropractic Humanities is the third), read "The Importance of Our Chiropractic Journals" in the Aug. 26, 2012 issue of DC.
Are Concussion Return-to-Play Criteria Too Lax?
Objective: The purpose of this literature review was to demonstrate, through examples in the current literature, the cumulative and long-term effects of multiple concussions, postinjury protocols, and the efficacy of current and past return-to-play guidelines.
Methods: A PubMed search was performed using the keywords and key phrases: concussions and long-term effects, concussions and return to play, and multiple concussions. We limited the search to articles that had been published from August 2007 to August 2012 and were specific to human participants. Of the 450 total articles that the search returned, we selected studies specifically demonstrating athletes who were symptom-free, passed neuropsychological testing, returned to play, and were tested in measures of postural control, transcranial magnetic stimulation, electroencephalographic studies, and magnetic resonance imaging spectroscopy.
Results: Selected studies show evidence that, although a previously concussed athlete may be symptom-free and returned to a neuropsychological baseline, the athlete may continue to have prolonged neurological abnormalities that could disqualify them from being ready to return to play.
Conclusion: It appears that some neurological deficits persist beyond the current return-to-play standards and that discrepancy exists between common practices of returning athletes to competition and new standards of published research.
Source: Porcher N, et al. A narrative review of sports-related concussion and return-to-play testing with asymptomatic athletes. JCM, Dec 2013;12:260-268.
Vertebral Artery Blood Flow After Spinal Manipulation
Objective: The objective of the study was to investigate the cerebrovascular hemodynamic response of cervical spine positions including rotation and cervical spine manipulation in vivo using magnetic resonance imaging technology on the vertebral artery (VA).
Methods: This pilot study was conducted as a blinded examiner cohort with four randomized clinical tasks. Ten healthy male participants ages 24 to 30 years (mean, 26.8 years) volunteered to participate in the study. None of the participants had a history of disabling neck, arm, or headache pain within the last six months. They did not have any current or history of neurologic symptoms. In a neutral head position, physiologic measures of VA blood flow and velocity at the C1-2 spinal level were obtained using phase-contrast magnetic resonance imaging after three different head positions and a chiropractic upper cervical spinal manipulation. A total of 30 flow-encoded phase-contrast images were collected over the cardiac cycle, in each of the 4 conditions, and were used to provide a blood flow profile for one complete cardiac cycle. Differences between flow (in milliliters per second) and velocity (in centimeters per second) variables were evaluated using repeated-measures analysis of variance.
Results: The side-to-side difference between ipsilateral and contralateral VA velocities was not significant for either velocities (P = .14) or flows (P = .19) throughout the conditions. There were no other interactions or trends toward a difference for any of the other blood flow or velocity variables.
Conclusions: There were no significant changes in blood flow or velocity in the vertebral arteries of healthy young male adults after various head positions and cervical spine manipulations.
Source: Quesnele JJ, et al. Changes in vertebral artery blood flow following various head positions and cervical spine manipulation: JMPT, Jan 2014;37:22-31.
Nerve Testing With Manual Palpation, Pressure Algometry
Objective: Nerve palpation is a method of clinically identifying mechanosensitivity of neural tissue by means of pressure algometry and manual palpation. There are few investigations of the reliability of lower limb nerve palpation, and femoral nerve palpation has never been previously reported. The aim of this study was to investigate the reliability of nerve palpation of the femoral, sciatic, tibial, and common peroneal nerves and to report normative values for the femoral nerve.
Methods: The four lower limb nerves were palpated in 39 healthy volunteers using pressure algometry and manual digital palpation. Measurements were taken twice by one rater (intrarater reliability) and once by a second rater (interrater reliability).
Results: Intraclass correlation coefficients for pressure pain thresholds (PPTs) via pressure algometry of the femoral, common peroneal, tibial, and sciatic nerves were 0.69, 0.84, 0.64, and 0.9 for intrarater reliability, respectively, and 0.82, 0.7, 0.56, and 0.75 for interrater reliability. k values for manual palpation were 0.59, 0.55, 0.42, and 0.60 for intrarater reliability and 0.30, 0.49, 0.37, and 0.60 for interrater reliability. Males demonstrated significantly higher PPTs than females for the femoral, sciatic, and tibial nerves, and differences in PPTs were present between right and left sides.
Conclusion: Nerve palpation of the femoral, common peroneal, and sciatic nerves using pressure algometry demonstrated good to excellent reliability, whereas the tibial nerve PPTs showed moderate to good reliability. Manual palpation measurements demonstrated fair to moderate reliability.
Source: Fingleton CP, et al. Intraexaminer and interexaminer reliability of manual palpation and pressure algometry of the lower limb nerves in asymptomatic subjects. JMPT, Feb2014;4(37):97-104.
Physical Function After Anterior Cervical Decompression and Fusion Surgery
Objective: The purpose of this study was to evaluate neck-related physical function in individuals 11 to 14 years after anterior cervical decompression and fusion (ACDF) surgery for degenerative cervical disk disease and to compare the long-term outcome of two surgical techniques, including the Cloward procedure and cervical intervertebral fusion cage.
Methods: In this cross-sectional study, 51 individuals, 11 years or more after ACDF, underwent testing of cervical active range of motion, hand-grip strength, static and dynamic balance, neck muscle endurance, and completed pain ratings. The participants’ values were compared with values of age- and sex-matched healthy individuals to evaluate impairments. Correlations between different test scores and pain were performed. Group differences were analyzed between the two surgical techniques.
Results: Sixty-five percent and 82% exhibited impairment in ventral and dorsal neck muscle endurance, respectively. Impairment rates of 18% to 39% for cervical active range of motion, 27% to 43% for hand-grip strength, 37% for standing balance, and 35% for dynamic balance were recorded. Twenty-nine percent of the participants had impairment (>30 mm visual analog scale) in pain. There were no significant differences in physical function between the two surgical treatment groups (Cloward procedure or cervical intervertebral fusion cage) (P = .10-.92).
Conclusions: In those studied, a large percentage of patients who had anterior cervical decompression and fusion surgery have impairments in neck-related physical function when compared 11 to 14 years after surgery with age- and sex-matched healthy reference individuals. Neck-specific function, but not balance, was statistically correlated to pain. Neck muscle endurance was most affected, and balance impairments were also present in one-third of the individuals. There were no differences in long-term physical function between the two surgical techniques.
Source: Hermansen A, et al. Evaluation of physical function in individuals 11 to 14 years after anterior cervical decompression and fusion surgery - a comparison between patients and healthy reference samples and between two surgical techniques. JMPT, Feb 2014;37:87-96.