Three-dimensional head axis of rotation during tracking movements. A tool for assessing neck neuromechanical function.

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.

Biomechanical analysis of an induced joint dysfunction (subluxation-mimic) in the thoracic spine of rabbits.

OBJECTIVE: The purpose of the present experiment was to evaluate functional biomechanics of the lesioned area in rabbits subjected to surgically placed vertebral lesions which may mimic a subluxation. It was hypothesized that wedging a bar between three adjacent vertebrae would lead to visual and palpatory alterations and also to a decrease in range of motion (ROM) at the affected segments. DESIGN: A controlled laboratory experiment was performed to measure directly ROM and to evaluate the functional and anatomic relationships of vertebrally lesioned rabbits. SUBJECTS: Twelve healthy adult New Zealand rabbits of either sex, weighing 3-5 kg, were maintained in the PCC animal facilities under normal husbandry conditions. Six operated controls and six experimentally lesioned rabbits were available for analysis. INTERVENTIONS: Rabbits were anesthetized and a vertebral lesion surgically placed at various locations along the thoracic spine. A stainless steel bar was implanted to produce a putative partial fixation and misalignment of three adjacent segments. The middle spinous process was forced contralaterally and slightly rotated relative to the adjacent two. At intervals ranging from a few weeks to several months postsurgery, the animals were evaluated for spinal ROM and also by visual and palpatory means for spinal misalignment. MAIN OUTCOME MEASURE: X rays, using rubber foam molds to standardize positioning, were taken pre- and postsurgery to measure ROM. Statistical analysis was made to compare ROM between the lesioned and adjacent areas of experimental and control animals. RESULTS: All but one of the experimental animals, but none of the controls, showed some reduced ROM on palpation at autopsy. Radiographic measures, however, showed that the ROM in the experimental animals as a group was not significantly reduced compared to control values, nor was there a significant ROM decrease compared to nonlesioned motor units within the experimental group. In some individual animals, however, there was a significant decrease in spinal ROM. CONCLUSIONS: This study failed to demonstrate any effect of the vertebral lesion on spinal ROM as measured radiographically, although by palpation the lesioned area did appear to be partially fixated in most animals. This surprising result may perhaps be explained by the large variability in measurements, the small number of subjects used or by inadequacies of X-ray positioning. Further work on biomechanical effects of vertebral lesions is clearly required.

Three-dimensional head kinematics and clinical outcome of patients with neck injury treated with spinal manipulative therapy: a pilot study.

OBJECTIVE: Finite helical axis parameters (FHAP) of the cervical spine and clinical measures were obtained to evaluate neck function and the clinical effects of spinal manipulative therapy in patients with "whiplash" (WL) type neck injury. DESIGN: Descriptive case series, 1 yr follow-up. SETTING: Three private chiropractic practices. SUBJECTS: Ten consecutive new patients with a history of neck injury, nine asymptomatic, volunteer controls. INTERVENTIONS: A 6-wk regimen of short lever manually assisted adjustments with an Activator Instrument, while acute, four patients received interferential electrotherapy. MAIN OUTCOME MEASURES: Cervical FHAP during normal movements, neck pain (visual analogue scale), active cervical range of motion and follow-up questionnaire. RESULTS: Based on six patients, the FHAPs appeared to mirror the clinical condition, being markedly deviant from the patterns observed in the control group for at least one or more of the tracking tasks for all but one of the patients. Mean pain scores decreased from 44.1 to 10.5 (t = 4.93; p < .0001) and mean total range of motion increased from 234 to 297 degrees (t = 5.68; p < .0001). At 1 yr, seven respondents noted stability of their symptoms at or near the level reported immediately after the 6-wk treatment period. CONCLUSIONS: Based on these preliminary data: a) FHAPs may aid in diagnosing and monitoring treatment of neck dysfunction, b) spinal manipulative therapy may be beneficial to some patients with neck injury and future study is warranted as a means to promote recovery of patients with neck injuries.

Use of severe combined immunodeficient (SCID) mice to produce human hybridoma ascites.

The use of the severe combined immunodeficient mouse (SCID), CB-17/Icr//Imd-SCID, was investigated for the production of human hybridoma ascites containing human antibody. Human-human hybridomas, generated from the fusion of lymphocytes isolated from regional draining lymph nodes of cancer patients with the SHFP-1 fusion partner, were injected i.p. at various cell concentrations into pristane-primed SCID mice. Ascites growth was typically observed at 7-14 days postinoculation. No significant differences in ascites yield or production were observed between IgG- and IgM-secreting hybridomas. Yields of immunoreactive human immunoglobulin ranged from approximately 0.5 to 3 mg/ml of harvested ascites. The ease and relatively low cost suggest that the use of SCID mice is preferred over conventional and costly large-scale industrial procedures.

Preliminary study of blood pressure changes in normotensive subjects undergoing chiropractic care.

The purpose of this study was to evaluate the reliability of clinical blood pressure readings and to begin a series of experiments to determine if chiropractic adjustments cause any significant changes in blood pressure. Seventy-five students undergoing routine chiropractic health care at Palmer College of Chiropractic Clinic volunteered to participate in the blood pressure measurement protocol in one 10-min visit. These subjects were placed into one of two groups, based on the clinical findings from the chiropractic examination. One group, the Experimental group was formed on the basis that they had subluxations in the cervical spine and also were adjusted specifically for them. The Control group was similar but lacked manipulable cervical subluxations on that particular day and were not adjusted. Clinical and experimental procedures were carried out identically on each group. Subjects were examined by standard Gonstead palpatory methods after 5 min of quiet sitting in a cervical chair. Blood pressure was recorded by right arm cuff sphygmomanometer by an experienced chiropractor immediately before and again immediately after either the specific cervical adjustment or the control procedure, which was simply motion palpation. The doctors measuring blood pressures did not know to which group the subject had been assigned. Both systolic and diastolic blood pressures were statistically significantly lowered in the Experimental but not the Control group (p less than 0.01). The difference in the mean blood pressures was small and was brought about by 14 of the Experimental subjects who experienced a clinically relevant 10-20 mm hg drop. Reliability of blood pressure measurements by two doctors was established under similar conditions in an additional 25 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Reliability study of detection of somatic dysfunctions in the cervical spine.

A reliability study was conducted to determine whether palpatory findings on the cervical spine, obtained under normal chiropractic clinical conditions were reproducible. Forty normal freshman chiropractic students underwent static and motion palpation of their cervical spines by three different chiropractors. Intra- and inter-examiner reliability of findings was assessed by concordance statistics (weighted kappa). There was statistically significant agreement of findings for all three examiners only for fixations in the lower cervical spine. There was a total lack of statistical agreement of fixation findings, both intra- and inter-examiner, in the middle cervical area. Agreement of fixation findings was intermediate for the upper cervicals and also for the other palpation parameters that were used (e.g. muscle spasms and pain) throughout the cervical spine. The results generally indicate a relatively high level of replicability of palpatory findings in a normal asymptomatic population by 'typical' chiropractors. The relation of these palpatory findings to vertebral lesions, or subluxations, are unknown.

Inter- and intra-examiner reliability of leg-length differential measurement: a preliminary study.

The phenomenon of "short leg" has long been used and debated clinically. A uniquely chiropractic measurement technique was not studied in any of the few studies of reliability of measurement which have been reported. An inter- and intra-examiner reliability study was therefore performed to validate a prone leg length-differential test. Naive students (n = 40) were called, in random order, into three adjacent examining rooms where three experienced chiropractic clinicians measured differential leg lengths. Using standard placement a tape measure was read to the nearest mm to detect inequalities at the shoe-sole interface. The leg length differences were recorded, for both the straight and flexed legs prone positions, twice by each of the three clinicians. Intraclass correlations were significant for the two independent readings for all three examiners, indicating high reliability of the test. Good agreement among examiners was indicated as well by significant intraclass correlation in two of the three possible examiner combinations. These results argue strongly for the reality of the leg length inequality phenomenon and also that it can be reliably measured.

Roentgenographic measurement of atlas laterality and rotation: a retrospective pre- and post-manipulation study.

Case records (523) were chosen at random from the files of J.F. Grostic, D.C. (deceased) for retrospective determination of the effects of chiropractic adjustments on atlas positioning relative to the occiput and axis. For each patient the recorded degrees of (1) atlas rotation and (2) laterality, both before and soon after spinal manipulative therapy, were extracted from the x-ray reports. Frequency histograms were made of pre- and post-adjustment degrees of laterality and rotation and the relative change of values analyzed statistically. Before manipulation, nine patients had zero atlas rotation and none were zero with respect to laterality. The mean deviation from zero degrees of "misalignment," was 2.75 and 2.63 respectively for rotation and laterality. After manipulation the corresponding values were 1.43 and 140, which is a statistically significant change. The numbers of patients who had zero rotations and laterality after adjustment were 156 and 151 respectively. In 63 patients the post-adjustment values were zero for both parameters. Under the circumstances presented in this retrospective study, these data tend to show that spinal manipulative therapy altered the position of atlas in the postulated direction.

Effects of EMG biofeedback on diabetes.

A case is described in which a juvenile-onset insulin-requiring diabetic was given frontalis EMG biofeedback. For 6 years prior to biofeedback training, the subject had been healthy and stable on 22-24 units regular insulin injected once daily. During 8 weeks of standard feedback training for relaxation of frontalis muscle activity, the subject twice reduced her daily insulin dosages. At the end of 8 weeks, the subject was receiving 17-18 units regular insulin daily but was still unstable, sometimes being hyperglycemic, sometimes hypoglycemic. Because of disturbing symptoms associated with this instability, biofeedback was discontinued for 6 months, at which time the subject was again healthy and stable on the equivalent of 18-19 units regular insulin daily. After this period, biofeedback was again given for 1 week, but the subject again became highly unstable and biofeedback was permanently stopped. Caution is suggested when dealing with diabetic patients.