July 2002

CBP® Research Wins Top Honors

 at ISSLS Conference

At the 29th Annual Meeting of the International Society for the Study of the Lumbar Spine (ISSLS) May 14-18, 2002, CBP®  research was awarded ISSLS’ Sofamor Danek best Poster Award. This CBP® research was entitled “Prediction of Spinal Deformity following disc degeneration and osteoporosis” by Keller TS, Harrison DE, Colloca CJ, Harrison DD, and Janik TJ. Receiving the award for CBP® researcher was Tony Keller, PhD, Chair of the Mechanical Engineering Department at the University of Vermont. There were several chiropractors who presented research posters at this prestigious orthopedic research conference.

            Each year, this meeting represents an international gathering of leading spine researchers from numerous disciplines, each interested in advancing the knowledge related to the lumbar spine.  This year, 369 papers were submitted to ISSLS and 94 were accepted for platform presentation, another 40 for special poster presentations, and 96 were accepted for poster presentation totaling 230 research papers.  Although the majority of papers had specific relevance for orthopedic surgery, the chiropractic profession was well represented as evidenced by the numerous accepted papers by D.C. authors at the conference.  This report will summarize several of the studies presented (by chiropractors and others) that we believe are of great interest to the profession.

Low Back Pain After Traffic Collisions: A Population-Based Cohort Study

            J. David Cassidy, D.C., Ph.D. from the University of Alberta and co-workers

presented their epidemiological research into the incidence and prognosis

for low back pain resulting from traffic collisions and its relationship to

tort or no-fault compensation systems.                   In reviewing over 9,000 personal

injury claims, 50 percent reported post-traumatic low back pain.  Changing from a tort system to no-fault reduced the median time-to-claim closure by about

300 days and lawyer involvement was the strongest predictor of delayed claim

closure.  Claim closure and health recovery were found to be highly associated and other factors including age, gender, pain, fault for the collision and initial health-care provider were also determined to be important factors. (Cassidy JD, Carroll LJ, Cote P, Berglund A, Nygren A. ISSLS 2002:p.1.)

Changes in Spinal FunctionFollowing Low Back Pain

        From the University of Bristol, U.K., Dr. Patricia Dolan and co-authors

reported functional assessments in low back pain patients.  “The assessment

involved measures of hip and spinal mobility, standing posture, back and

quadriceps muscle strength, EMG measures of back muscle endurance during

high and low intensity fatigue tests, bending and compressive stresses

during lifting and a number of psychometric scores.”  Subjects were followed

up with questionnaires for three years and 17 of those subjects reporting a

first episode of serious low back pain during the final year of follow up

were reassessed every six months for another two years.

            The results of the study indicate that changes in spinal function occur after a first episode of serious low back pain and that without any intervention, recovery to pre-back pain levels can be slow.          The research also concluded that changes

in spinal function appeared to influence future pain and disability, suggesting that early intervention to redress these changes may help prevent future episodes of low back pain. (Dolan P, Mannion AF, Adams MA.  ISSLS 2002:p.10.)

Prediction of Spinal Deformity Following Disc Degeneration and Osteoporosis

        Dr. Tony Keller, chair of the department of Mechanical Engineering at the

University of Vermont, collaborated with chiropractors from Chiropractic Biophysics®, Non-profit, to understand the biomechanics of age-related spinal deformity and concomitant height loss associated with vertebral osteoporosis and degenerative disc disease.

            A postural loading model was derived from digitized lateral radiographs of 20 subjects who assumed a neutral and anterior translated thoracic posture.  Body weight loads were applied to the model, intervertebral disc and vertebral body forces and deformation were computed, and the new spine geometry was calculated.

            The model predicted abnormal postures of anterior translation of the cervical vertebrae and thoracic kyphosis deformity as consequences to an anteriorly translated thorax and the model predictions suggest that such deformity is also the result of vertebral compression fractures exacerbated by the posture. (Keller TS, Harrison DE, Colloca CJ, Harrison DD, Janik TJ.  ISSLS 2002: p. 95)

Prediction of Sagittal Plane Loadsand Stresses in the Lumbar Spine. A Comparison of Neutral Posture and Anterior Translation of the Thoracic Cage

        In a companion paper to the spinal deformity paper above, Deed Harrison,

D.C. and co-workers used a previously validated upright spinal model to predict loads and stresses in the intervertebral discs and calculated the extensor muscle loads for changes occurring from the neutral standing posture to anterior translation of the thorax.

            Twenty Life University students volunteered to participate in the study having sectional lateral full spine radiographs obtained in the two postures.                         The research found that loads and stresses on the L5-S1 disc nearly doubled and a significant trunk extensor muscle effort was required to sustain the posture.  This work concluded that abnormal posture such as  that seen in anterior translation of the thorax could be a contributor to lumbar disc pathologies including disc degeneration and spondylolisthesis.  (Harrison DE, Colloca CJ, Keller TS, Harrison DD, Janik TJ.  ISSLS:p.159)

Decrease of Paraspinal Muscle EMGActivity During Spinal Manipulation

        From the Palmer Center for Chiropractic Research, principal investigator,

Jim DeVocht, D.C., Ph.D. measured the lumbar surface EMG activity of 16 patients receiving spinal manipulation with an Activator II Adjusting Instrument.  Decreases in muscle activity were the most commonly observed finding.  This study, although preliminary, seems to be consistent with hypotheses that spinal manipulation can reduce muscle spasm in certain instances.  (DeVocht JW, Pickar JG, Wilder DG.  ISSLS 2002:p.141)

Proprioceptive Errors From Lumbar Paraspinal Muscle Spindles Induced by

Short-Term Changes in Lumbar Vertebral Position in the Anesthetized Cat

        Also from Palmer’s research facility came the continued line of study from

Joel Pickar, D.C., Ph.D. who measured this time muscle spindle activity from longissimus or multifidus muscles during various induced spinal positions.  Pickar et al. reported that holding the lumbar paraspinal muscles short for as little as five seconds sensitized their spindles to subsequent muscle stretch.  Thus, as noted, “the data raise the possibility that static postures an individual assumes can alter normal proprioceptive

information from paraspinal muscle spindles.  Inappropriate muscle activity

from these proprioceptive feedback errors could contribute to injury of

spinal tissues” as well.  (Pickar JG, Kang YM.  ISSLS 2002: p. 106)

The Effects of Side Posture Positioning and Spinal Adjusting on the Z Joints

        Gregory Cramer, D.C., Ph.D. and colleagues from National University of

Health Sciences presented their unique work investigating side posture positioning and adjusting on gapping of the zygapophyseal (Z) joints.

            Sixty-four patients were randomized into various groups to investigate the

effect of positioning and adjusting on Z joint gapping using MRI scans.

            Compared to controls, it was clearly demonstrated that side posture spinal

adjusting provided the greatest gapping of the lumbar facet joints.  The authors note that this research may help  in the understanding of the mechanism of action of this procedure.  (Cramer GD, Gregerson DM, Knudsen JT, Hubbard BB, Ustas LM, Cantu JA.  ISSLS 2002:p.140)

F Waves of Peroneal and Tibial NerveProvide Unique Information in Ongoing

L5 and S1 Radiculopathies

        Chiropractor and neurologist Scott Haldeman, D.C., M.D., Ph.D. collaborated with researchers at Upstate Medical University in Syracuse, NY to investigate neurophysiological responses (F waves) in L5 and S1 radiculopathy patients.  The authors reported their results of 227 patients with lumbosacral radiculopathy.  “The ongoing active process of root lesions was confirmed by abnormal EMG findings of denervation potentials

(fibrillation potentials and complex repetitive discharges) in the paraspinal muscles and the L5 and/or S1 myotomes.”  Among other findings, 47% of L5 root lesions were found to have abnormal peroneal nerve F wave responses and 73% of cases with S1 root lesion had abnormal H-reflex.   

            The authors concluded that comparisons between the same nerve on two sides and between the two nerves in the same leg increase the diagnostic sensibility root lesions.  (Zhu Y, Weber R, Li J, Chu J, Haldeman S, Yuan HA. ISSLS 2002:p.158)