Archive for category Research

ABSTRACT

BACKGROUND AND OBJECTIVE

The prone comparison of  changes in leg alignment is commonly used to identify musculoskeletal  dysfunction by chiropractors. Despite its widespread use as a diagnostic  tool, confusion exists about the reliability of these measures. A  possible problem is this methods dependence upon the clinician to  accurately assess leg length asymmetries by visual inspection. The  purpose of this investigation was to utilize a precise optoelectric  device to determine 1) Leg length asymmetries prior to and after a  random series of isolation tests, and 2) Heel trajectories during the  performance of these isolation tests.

METHOD

-Four subjects were tested in the Motor Control  Laboratory at ASU. During each testing Session the subjects lay prone on  a portable adjusting table with infrared light emitting diodes affixed  with adhesive to their posterior heels, and posterior occiput.  Additional markers were placed on a moveable reference bar placed near  the subject’s feet. The reference bar was aligned to be perpendicular to  the body, and was independent of the adjusting table. Prior to any data  ‘Collection, each patient was assessed visually by a chiropractor for  the incidence of any leg length inequality, which was recorded for later  use. After the visual assessment, the reference bar was placed at its  permanent location, and a second leg length measurement was made by a  second investigator by measuring marker location of each heel from the  bar with a scale marked in millimeters. Each measurement (visual and  from the bar) were kept blind from the other respective investigator.  Data collection then proceeded with the optoelectric device. Data were  collected for 8 seconds at 50 Hz during the following conditions: no  movement, head-up, chin-tuck, pressure test right transverse process of  C-1, or pressure test left transverse process of C-1, The initial 5  trials were in the order mentioned in the prior sentence; 5 trials of  each condition were then collected in a randomized order for a total of  30 trials. After all data were collected, leg length assessments were  carried out by the two investigators as was completed prior to data  collection. After data collection was complete, digital data were  filtered at 2 Hz and 0′ rotated mathematically into a local reference  frame within which the bar represented one axis in a 3-D frame. This  allowed measurements to be examined along an axis perpendicular to the  bar, the expected axis of lengthening or shortening of each leg. Two types of analyses were completed for each subject. Leg  length difference analysis consisted of examining the heel positions at  the; beginning and end of the entire testing session and comparing the  data to the investigator’s manually measured reports.


Reference: John K. DeWitt, B.Sc.E., Paul J. Osterbauer.  D.C., George E. Stelmach, Ed.D. & Arlan W. Fuhr. D.C.;  Optoelectric Measurement of Leg Length Inequalities Before, During, and  After Isolation Tests; Proceedings of the 1994 International  Conference on Spinal Manipulation. Palm Spring, CA, June 10-11, 1994, p.  24-25.

Exercise and Sport Research Institute, Arizona State University Tempe, AZ 85287-0404 +Activator Methods. Inc. 3714 E. Indian School Road, Phoenix. AZ.

Read More

Abstract

Activator Methods Chiropractic Technique (AMCT) was developed by Warren Lee, DC and Arlan Fuhr, DC. In the evolution of AMCT, Lee and Fuhr drew on elements of several other techniques, including Logan Basic, Van Rumpt, Truscott and Derefield, and developed innovation equipment, such as the Activator adjusting instrument (AAI) and an adjusting table designed specifically for AMCT. Based on oral history interviews, this paper records the early lives of Lee and Fuhr, their entries into chiropractic, influences on their personalities, the development of their technique and the seminars which presented it to the chiropractic profession.


Chiropr J Aust. Mar 1994 (Mar); 24(1): pp.28-32.

Author information: Richards DM.

Read More

Abstract

OBJECTIVE:

To determine the biomechanical characteristics of five clinically common methods of cervical spine manipulation.

DESIGN:

Descriptive study.

SETTING:

Human Performance Lab, University of Calgary.

PARTICIPANTS:

Five volunteer practitioners treating symptomatic patients from their own clinical populations.

INTERVENTION:

Five commonly used methods of cervical spine manipulation: lateral break (LAT), Gonstead (GON), Activator (ACT), toggle (TOG), rotation (ROT).

MAIN OUTCOME MEASURE:

Mean thrust duration (msec), normalized mean peak force (N), slope (N/msec), force profile (graphic representation of the above values.

RESULTS:

Outcome measures for each manipulative technique were as follows: LAT = normalized mean peak force of 102.2 N at 86.7 msec, GON = 109.8 N at 91.9 msec, ACT = 40.9 N at 31.8 msec, TOG = 117.6 N at 47.5 msec, ROT = 40.5 N at 79.1 msec.

CONCLUSION:

The observed differences and similarities in force profiles between the five techniques studied here may partly be the manifestation of how a particular technique delivers force to the cervical spine. The clinical significance of force profile characterization is not yet known.


J Manipulative Physiol Ther. 1993 Nov-Dec;16(9):573-7. [PMID:8133191]

Author information: Kawchuk GN, Herzog W. University of Calgary, Faculty of Physical Education, Alberta, Canada.

Read More

Abstract

The purpose of this study was to investigate  the relation between preload and peak forces during Spinal Manipulative  Therapy (SMT). Forces during clinical trials of SMT were measured on the  sacroiliac joint, the thoracic spine, and the cervical spine using a  thin, flexible pressure pad (EMED Inc.). Preload forces were found to  correlate well with peak forces during SMT, suggesting that the force  required to move the joint of interest to the end range of passive  motion (i.e., the preload force required) influences the magnitude of  the treatment thrust. Furthermore, the change in force from preload to  peak (∆F) also correlated well with peak thrusting forces for all SMTs  tested, suggesting that the stiffness of the joint of interest at the  limit of passive range of motion may be related to peak thrusting  forces. Preload and corresponding (∆F) forces were not correlated  highly.


Journal of the Neuromusculoskeletal System. 1993; 1(2): 52-8.

Author information: Herzog W, Kawchuk GN, Conway PJ.  Human Performance Laboratory, Faculty of Physical Education, The University of Calgary, Calgary, Alberta, Canada.

Read More

Abstract

The purpose of this article is to report normal variation in the screw (helical) axis of rotation of the head during various types of natural tracking movements. Nine normal subjects and eighteen subjects with neck injury faced a grid of targets separated by 10-degree intervals, and were instructed to use a head pointer (laser) to track whatever target was lit. Various horizontal, vertical, and oblique target sequences were employed. The normal subjects exhibited several consistent trends in finite screw axis parameter variation: vertical movements have a laterally-directed axis whose midsagittal plane crossing position is a function of the head orientation (typical range C3-T1); oblique movements have a diagonally-directed axis and an even greater orientation-specific range (C1-T1); and horizontal movements have a vertical axis that is modified near horizontal orientation extremes and is asymmetrically influenced by upward and downward bias orientations. Subjects with neck injury were seen to exhibit a variety of abnormal screw axis patterns.


Spine (Phila Pa 1976). 1993 Jul;18(9):1178-85. [PMID:8362323]

Author information: Winters JM, Peles JD, Osterbauer PJ, Derickson K, Deboer KF, Fuhr AW. Arizona State University, Tempe, AZ.

Read More

ABSTRACT

Changes in apparent leg length”(leg retraction) have been used  by many as a means of locating subluxation in various Joints. The leg  assessment is based on the assumption that unequal muscular contraction  (e.g. hyper irritable muscles) about the spine and pelvis have the  ability to retract one leg relative to the other. Despite Claims of  usefulness, many problems are inherent in the prone leg assessment such  as: a) measurement error; b) subject positioning by the examiner  (expectancy bias) and; c) interference with die surface of the examining  table. There have been prior attempts to quantify the amount of leg  length changes that occur during a treatment session, but most have  suffered due to the lack of a measurement technique which provides the  necessary accuracy in the recording of slight changes in heel position.  The purpose of this study was to quantify involuntary, movements that  result from neck flexion and extension maneuvers. Five subjects  exhibiting involuntary leg reactions were tested using an optoelectric  motion analysis system. During each testing session, the subject lay  prone on an adjusting table while infrared light emitting diodes (IREDs)  were affixed to the heels of fracture boots. In the rest position, the  neck was in neutral flexion so the face rested on the surface of the  table. Prior to testing, the examination area was in neutral flexion so  the face rested on the surface of the table. Prior to testing, the  examination area was calibrated resulting in RMS errors of less than 0.3  mm. Data were collected for ten seconds by three cameras positioned to  record movement of the IREDs. During each testing session, each subject  preformed two movements; a head-up movement, during which the subject  extended the neck and then returned to a resting position, and a  chin-tuck movement, in which the subject flexed the neck and then  returned to a resting position. A testing session consisted of three  no-movement baseline trials, followed by three head-up trials and three  chin-tuck trials. Examination of output displacement histories showed  that during all trials, movement occurred at the heels in the direction  of the subject’s longitudinal axis. During the head-up trials, a  majority of cases showed a net shortening in heel position during head  movement.


Reference: John K. Dewitt. B.Sc.E, Paul J.  Osterbauer, D.C., George E. Stelmach, Ed.D., & Arlan W. Fuhr. D.C.;  Optoelectric Measurement of Leg Length Changes During Isolation Tests;  Proceedings of the CCR’s 8th Annual Conference on Chiropractic  Science in Health Policy and Research, Monterey, CA, June 18-20, 1993,  pp. 156-7.

Affiliation: Arizona State University, Phoenix. Arizona and National Institute for Chiropractic Research, Phoenix, AZ.

Read More

Abstract

OBJECTIVE:

A study was undertaken to assess the stability of leg alignment reaction to a pressure challenge and its responsiveness to an adjustive intervention.

DESIGN:

Prospective, double-blind clinical trial of a diagnostic test.

SETTING:

Laboratory: Center for Technique Research.

PARTICIPANTS:

Forty-two chiropractic college students, faculty and staff.

INTERVENTIONS:

A high-velocity, low-amplitude, short lever adjustment of a single vertebra from among C1 and T3-T7; or a sham adjustment similar to a manual diagnostic pressure test at C1, T3-T7 or T9-T10.

MAIN OUTCOME MEASURES:

Leg alignment reactivity: An increase in leg alignment discrepancy (yes or no) following a metered pressure challenge to a vertebra.

RESULTS:

On average, stability was poor at T3-T7 (Kappa = 0.04), moderate at C1 (K = 0.47), and fair for sham pressure tests (K = 0.30). Responsiveness: The proportion of positive baseline leg alignment reactions that responded (became negative) to sham adjustment was 95% at T3-T7 and 55% at C1. Further analysis was untenable since too few vertebrae were implicated for an adjustment.

CONCLUSIONS:

For the population investigated, the majority of the responsiveness of the leg alignment diagnostic test to a rotatory adjustment appears to be a diagnostic illusion (i.e., background noise unrelated to a treatment intervention). Further research with different subject populations, regions of investigation, leg alignment measurement techniques and vertebral challenge techniques are indicated.


J Manipulative Physiol Ther. 1993 Jun;16(5):306-11. [PMID:8345313]

Author information: Haas M, Peterson D, Rothman EH, Panzer D, Krein R, Johansen R, Solomon S. Research Department, Western States Chiropractic College, Portland, OR 97230.

Read More

Abstract

OBJECTIVE:

A study was undertaken to assess the reliability of detecting leg alignment changes (reactivity) and to determine if the observed leg alignment reactivity can be attributed to a rotatory articular pressure challenge.

DESIGN:

Prospective double-blind crossover trial of a diagnostic test.

SETTING:

Laboratory: Center for Technique Research.

PARTICIPANTS:

Forty-two chiropractic college students, faculty and staff.

INTERVENTIONS:

A standardized force of 2 or 3 kg was applied with a 1 cmrubber-tipped pressure algometer on the lateral aspect of the T3-T7 spinous processes and the posterior aspect of the lateral masses of C1.

MAIN OUTCOME MEASURES:

Leg alignment reactivity: an increase in leg alignment discrepancy (yes or no) following a diagnostic intervention.

RESULTS:

The reliability for detecting leg alignment reactivity was poor: on average, Kappa = 0.05 in the thoracics and 0.06 at C1. On average, the attributable risk of leg alignment reactivity (pressure test risk–sham test risk) was less than 4%. In many cases, the sham rate was greater than the pressure test rate.

CONCLUSIONS:

For the population investigated, leg alignment reactivity to rotatory pressure testing can, in the majority of cases, be attributable to background noise. This procedure was not found to be viable for identifying vertebrae for adjustment. Further research with different subject populations, regions of investigation, leg alignment measurement techniques and vertebral challenge techniques are indicated.


J Manipulative Physiol Ther. 1993 May;16(4):220-7. [PMID:8340716]

Author information: Haas M, Peterson D, Panzer D, Rothman EH, Solomon S, Krein R, Johansen R. Research Department, Western States Chiropractic College, Portland, OR.

Read More

Abstract:

Background and Objectives:

Knowledge of spine  segment motion patterns or “kinematics” is of interest to understanding  the time-dependent or viscoelastic behavior of the spine, postural  kinematics, vibration response of the spine, and response of the spine  to chiropractic manipulations. The ability to quantify in vivo spine  segment “kinematics” is clinically significant in terms of both the  diagnosis and treatment of spinal disorders and LBP. The objectives of  this study were to a) study the relative motions of the normal and  abnormal lumbar spine in response to transverse (postero-anterior)  manipulative thrusts, and b) mathematically model the dynamic  viscoelastic behavior of the spine.

Method:

An intervertebral motion measuring device (IMD) was  used to quantify the in vivo Interspinous kinematic behavior of the  normal (1 volunteer) and unstable (2 patients with abnormal lumbar discs  consulting for spine surgery) human lumbar spine. The IMD is a spatial  linkage system capable of measurement of motion in the sagittal plane,  and was rigidly attached to the L2-L3 and L3-L4 spinous processes using  2.4 mm Steinmann pins. Rotation, translation and shear of the lumbar  vertebrae were obtained in response to transverse impulses from an  Activator adjusting instrument (AAI) applied to the spinous process of  adjacent segments of the thoraco-lumbar spine with the patients lying  prone. Impulse force and acceleration in transverse plane were measured  using a uniaxial load cell and accelerometer.

Results:

The impulses (= 100N peak, < 100 msec duration)  produced exponentially damped oscillations in the lumbar motion segment  with displacement amplitude peaks (axial=0.5-1.0 mm, shear = 0.1-0.3 mm,  rotation=0.5-1 degrees) located at frequencies ranging from 10-15 Hz.  Alterations in the propagation of the impulse stimulus were observed in  the two patients with disc pathology. The kinematic data is currently  being analyzed using a dynamic, three-parameter linear solid  viscoelastic model to obtain intrinsic properties of the: ‘spine (moduli  or stiffness and viscosity).

Conclusions:

Although this study was conducted using  only a few human subjects, the preliminary results suggest that one may  be able to discriminate between normal and abnormal kinematic behavior  by measuring and analyzing the impulse response. of the spine in viva.  Such measurements may be used to evaluate the mechanical effectiveness  of various manipulative, surgical and rehabilitative procedures of the  spine.


Reference: T. Keller, PhD, M. Nathan, MS, and A. Kaigle,  MS Dept. of Mechanical Engr. University of Vermont. Burlington, VT and  Depts. of Orthopedics (Occupational Unit), Sahlgren Hospital, Goteborg,  Sweden. Proceedings of the FCER’s 1993 International Conference on Spinal  Manipulation. Montreal, Quebec, Canada, April 30-May 1: pp. 51-5.

Read More

Abstract:

Background and Objectives:

Little is known  about the dynamics of spinal manipulation and mechanical force manually  assisted short lever adjustments in particular. The purpose of this  study is to quantify the biomechanical response to impulsive loads  applied over the cervical spine. A previous study had enabled us to  quantify the response for the lumbar spine. This would enable the  estimation of the internal motion and loading that occurs due to the  instrument delivered short lever chiropractic adjustment.

Method:

An anthropomorphic model of the human  body has been constructed for this study. The Activator Adjusting  Instrument, a product of Activator Methods Inc, (Phoenix, AZ), is used  to produce the impulsive loads. The elements of the model involve bones,  ligaments, intervertebral discs and muscles which are constructed from  composite materials that closely mimic the passive properties of the  physiological systems. The instrumentation includes displacement,  acceleration and pressure transducers. The sampling rate of the data was  1,o00 Hz and filtering of the data is done using software.

Results:

The anthropomorphic model has been  used in a previous study to study the dynamics of spinal manipulation in  the lumbar spine. It has been found to be a reasonable substitute for  the human spine, in terms of the mechanical responses to forces and/or  torques. The present study involved data collection in the cervical  spine at the levels of C1, C2, C5 and C6. Preliminary data analysis has  been done and the movement response to applied thrusts on the spine has  been done qualitatively and a quantitative analysis is expected to be  done on data in the near future.

Conclusions:

Anthropomorphic modeling may prove useful  in understanding the dynamics of spinal manipulation, particularly when  integrated with computer modeling and in vivo studies. Acknowledgement: This study was funded by the National Institute of Chiropractic Research.


Reference: Sridhar Venkataraman, BS, Gary T. Yamaguchi,  PhD, Paul J. Osterbauer, OG, and Arlan W. Fuhr .DC, Arizona State  University, Tempe. AZ, The National Institute of Chiropractic Research,  Phoenix. AZ; Evaluating Mechanical Force Manually Assisted Short Lever  adjusting using an Anthropomorphic model; In: The proceedings of the  FCER’s 1993 International Conference on Spinal Manipulation, Montreal,  Quebec, Canada, April 30-May 1, Page 13.

Read More