Advanced Biostructural Correction (tm)

Neck retractions, cervical root decompression, and radicular pain.

Abdulwahab SS, Sabbahi M

1: J Orthop Sports Phys Ther 2000 Jan;30(1):4-9; discussion 10-2

Texas Woman's University, School of Physical Therapy, Houston 77030-2897, USA.

STUDY DESIGN: Two-group repeated measures. OBJECTIVES: To evaluate the changes in the flexor carpi radialis H reflex after reading and neck retraction exercises and to correlate reflex changes with the intensity of radicular pain.

BACKGROUND: Repeated neck retraction movements have been routinely prescribed for patients with neck pain. METHODS AND MEASURES: Ten nonimpaired subjects (mean age, 27 +/- 4 years) and 13 patients (mean age, 35 +/- 9 years) with C7 radiculopathy volunteered for the study. The flexor carpi radialis H reflex was elicited by electrical stimulation of the median nerve at the cubital fossa before and after 20 minutes of reading and after 20 repetitive neck retractions.

Subjective intensity of the radicular pain was reported before and after each condition using an analog scale. RESULTS: For patients with radiculopathy, a repeated-measures analysis of variance showed a significant decrease in the H reflex amplitude (from 0.81 +/- 0.4 to 0.69 +/- 0.39 mV), an increase in radicular symptoms after reading (from 4.2 +/- 1.3 to 5.6 +/- 1.4 on the visual analog scale), an increase in the H reflex amplitude (from 0.69 +/- 0.39 to 1.01 +/- 0.49 mV), and a decrease in pain intensity (from 5.6 +/- 1.4 to 1.5 +/- 1.3) after repeated neck retractions. There was an association between cervical root compression (smaller H reflexes) and increased pain during reading and between cervical root decompression (larger H reflex) and reduced pain (r = -0.86 to -0.60). Exacerbation of symptoms was found with a reading posture. There were no significant changes in the H reflex amplitude in the nonimpaired group. No

changes were found in reflex latency for either groups. CONCLUSIONS: Neck retractions appeared to alter H reflex amplitude. These exercises might promote cervical root decompression and reduce radicular pain in patients with C7 radiculopathy. The opposite effect (an exacerbation of symptoms) was found with the reading posture.

PMID: 10705591, UI: 20169769

EMG support of breig

@@1: Spine 1999 Jan 15;24(2):137-41

Cervical root compression monitoring by flexor carpi radialis H-reflex in

healthy subjects.

Sabbahi M, Abdulwahab S

School of Physical Therapy, Texas Woman's University, Houston, USA.

STUDY DESIGN: One-group, pretest-postest experimental research with repeated

measures. OBJECTIVE: To determine the effect of head postural modification on

the flexor carpi radialis H-reflex in healthy subjects. SUMMARY OF BACKGROUND

DATA: H-reflex testing has been reported to be useful in evaluating and treating

patients with lumbosacral and cervical radiculopathy. The idea behind this

technique is that postural modification can cause further H-reflex inhibition,

indicating more compression of the impinged nerve root, or recovery, indicating

decompression of the root. Such assumptions cannot be supported unless the

influence of normal head postural modification on the H-reflex in healthy

subjects is studied. METHODS: Twenty-two healthy subjects participated in this

study (14 men, 8 women; mean age, 39 +/- 9 years). The median nerve of the

subjects at the cubital fossa was electrically stimulated (0.5 msec; 0.2 pulses

per second [pps] at H-max), whereas the flexor carpi radialis muscle H-reflex

was recorded by electromyography. The H-reflexes were recorded after the subject

randomly maintained the end range of head-forward flexion, backward extension,

rotation to the right and the left, lateral bending to the right and the left,

retraction and protraction. These were compared with the H-reflex recorded

during comfortable neutral positions. Data were recorded after the subject

maintained the position for 30 seconds, to avoid the effect of dynamic postural

modification on the H-reflex. Four traces were recorded in each position. During

recording, the H-reflex was monitored by the M-response to avoid any changes in

the stimulation-recording condition. RESULTS: Repeated multivariate analysis of

variance was used to evaluate the significance of the difference among the

H-reflex, amplitude, and latency, in various head positions. The H-reflex

amplitude showed statistically significant changes (P < 0.001) with head

postural modification. All head positions, except flexion, facilitated the

H-reflex. Extension, lateral bending, and rotation toward the side of the

recording produced higher reflex facilitation than the other positions. These

results indicate that H-reflex changes may be caused by spinal root

compression-decompression mechanisms. It may also indicate that relative spinal

root decompression occurs in most head-neck postures except forward flexion.

CONCLUSIONS: Head postural modification significantly influences the H-reflex

amplitude but not the latency. This indicates that the H-reflex is a more

sensitive predictor of normal physiologic changes than are latencies. The

H-reflex modulation in various head positions may be-caused by relative spinal

root compression-decompression mechanisms.

PMID: 9926383, UI: 99125206

Surgical treatment of cervical spondylotic myelopathy: time for a controlled trial.

Rowland LP

Neurology 1992 Jan;42(1):5-13

Neurological Institute, Columbia-Presbyterian Medical Center, New York, NY 10032-3784.

Surgical procedures on the cervical spine are accepted therapies for the myelopathy of cervical

spondylosis. However, reported improvement rates vary widely, and many reports indicate

improvement in about one-half of the cases. It has not been proven that outcome after surgery is

better than the natural history or conservative therapy. Radiographic or imaging evidence of cord

impingement or compression may be seen in asymptomatic people. There are no clear guides to

the selection of patients who may benefit from the operation and there has been no

standardization of preoperative evaluation, trials of conservative therapy, ascertainment of

progressive disability, or assessment of outcome. A multicenter controlled trial might answer

these questions.

Analysis of the cervical spine alignment following laminoplasty and laminectomy.

Matsunaga S, Sakou T, Nakanisi K

Spinal Cord 1999 Jan;37(1):20-4

Department of Orthopaedic Surgery, Faculty of Medicine, Kagoshima University, Sakuragaoka,

Japan.

Very little detailed biomechanical examination of the alignment of the cervical spine following

laminoplasty has been reported. We performed a comparative study regarding the buckling-type

alignment that follows laminoplasty and laminectomy to know the mechanical changes in the

alignment of the cervical spine. Lateral images of plain roentgenograms of the cervical spine were

put into a computer and examined using a program we developed for analysis of the

buckling-type alignment. Sixty-four patients who underwent laminoplasty and 37 patients who

underwent laminectomy were reviewed retrospectively. The subjects comprised patients with

cervical spondylotic myelopathy (CSM) and those with ossification of the posterior longitudinal

ligament (OPLL). The postoperative observation period was 6 years and 7 months on average

after laminectomy, and 5 years and 6 months on average following laminoplasty. Development of

the buckling-type alignment was found in 33% of patients following laminectomy and only 6%

after laminoplasty. Development of buckling-type alignment following laminoplasty appeared

markedly less than following laminectomy in both CSM and OPLL patients. These results favor

laminoplasty over laminectomy from the aspect of mechanics.

Atrophy of the nuchal muscle and change in cervical curvature after expansive open-door laminoplasty.

Fujimura Y, Nishi Y

Arch Orthop Trauma Surg 1996;115(3-4):203-5

Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.

We analyzed computed tomography (CT) images and plain X-ray films of 53 patients who had

undergone expansive open-door laminoplasty, in a 3-year study. The relationship between the

postoperative changes in the nuchal muscles and those in the cervical curvature was investigated.

On postoperative CT images, the cross-sectional area of all nuchal muscles was reduced to

approximately 80% of its preoperative size. This atrophic change was especially intense in the

multifidus muscle and the semispinalis cervicis muscle. Postoperative cross-sectional area of the

deep nuchal muscles was reduced approximately 30% from its preoperative size. No significant

correlation was found between the all cross-sectional area of the nuchal muscles and the cervical

curvature. However, a weak correlation was found between the deep nuchal muscles area and

the curve index (correlation coefficient 0.29).

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Lordotic alignment and posterior migration of the spinal cord following en bloc open-door laminoplasty for cervical myelopathy: a magnetic resonance imaging study.

Baba H, Uchida K, Maezawa Y, Furusawa N, Azuchi M, Imura S

J Neurol 1996 Sep;243(9):626-32

We investigated lordotic alignment and posterior migration of the spinal cord following en bloc

open-door laminoplasty for cervical myelopathy. Fifty-five patients (32 men and 23 women)

were studied, with an average follow-up of 2.4 years. Radiological examination included

evaluation of lordosis of the cervical spine and spinal cord, degree of enlargement of bony spinal

canal, and the magnitude of posterior cord migration. We also correlated these changes with

neurological improvement. Postoperatively, there was an average of 5% loss of cervical spine

lordosis (P > 0.01) on radiographs and 12% reduction in the lordotic alignment of the spinal cord

(P > 0.05) on magnetic resonance imaging. Postoperatively, the size of the bony spinal canal

increased by 48%. Posterior cord migration showed a significant correlation with the

preoperative cervical spine and spinal cord lordosis (P < 0.05). Thirty-seven (67%) patients with

neurological improvement exceeding 50% showed significant posterior cord migration following

laminoplasty compared with those demonstrating less than 50% improvement (P = 0.01). Our

results suggest that a significant neurological improvement is associated with posterior cord

migration after cervical laminoplasty.

PMID: 8892062, UI: 97047142

Multilevel cervical spondylosis. Laminoplasty versus anterior decompression.

Hirabayashi K, Bohlman HH

Spine 1995 Aug 1;20(15):1732-4

Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.

Poor overall outcome and a high incidence of postoperative kyphosis and progressive

myelopathy have driven surgeons away from decompressive laminectomy as a treatment for

multilevel cervical spondylosis. Dr. Henry Bohlman advocates anterior decompression and fusion

as the best approach to the pathophysiology of this disorder, while Dr. Kiyoshi Hirabayashi

believes that laminoplasty represents an excellent strategy for patients with degenerative disease,

as well as those with ossification of the posterior longitudinal ligament.

Preoperative and postoperative magnetic resonance image evaluations of the spinal cord in cervical myelopathy.

Yone K, Sakou T, Yanase M, Ijiri K

Spine 1992 Oct;17(10 Suppl):S388-92

Department of Orthopaedic Surgery, Faculty of Medicine, Kagoshima University, Japan.

To evaluate the morphologic changes of the spinal cord in patients with cervical myelopathy due

to cervical spondylosis and ossification of the posterior longitudinal ligament, the authors

measured the thickness and signal intensity of the cervical cord with magnetic resonance imaging

in healthy adults and patients with cervical myelopathy, and compared these findings. In patients

with cervical myelopathy, the preoperative and postoperative magnetic resonance imaging

findings were compared with the severity of myelopathy and postoperative results. In healthy

adults, the anteroposterior diameter of the cervical cord was 7.8 mm at the C3 level and

decreased at lower levels. In the patients with cervical myelopathy, the preoperative spinal

anteroposterior diameter was significantly reduced at various levels corresponding to the stenosis

site within the vertebral canal. In the group with ossification of the posterior longitudinal ligament,

the minimal anteroposterior diameter of the cervical cord tended to decrease with increasing

severity of myelopathy. However no relationship was observed between the two parameters in

the cervical spondylotic myelopathy group. In the group with ossification of the posterior

longitudinal ligament, surgical results were good when the postoperative anteroposterior diameter

was increased, whereas in the cervical spondylotic myelopathy group there was no relationship

between the two parameters. In the patients with myelopathy, a high intensity area was observed

in about 40% of all patients before operation and about 30% after operation. However, the

presence or absence of a high intensity area did not correlate with the severity of myelopathy or

with surgical results in the group with ossification of the posterior longitudinal ligament and the

cervical spondylotic myelopathy groups.

PMID: 1440032, UI: 93068549

Neck and shoulder pain after laminoplasty. A noticeable complication.

Hosono N, Yonenobu K, Ono K

Spine 1996 Sep 1;21(17):1969-73

Department of Orthopaedic Surgery, Japan.

STUDY DESIGN: The authors retrospectively analyzed the prevalence and features of neck and

shoulder pain (axial symptoms) after anterior interbody fusion and laminoplasty in patients with

cervical spondylotic myelopathy. OBJECTIVES: To reveal the difference in prevalence of

postoperative axial symptoms between anterior interbody fusion and laminoplasty and to clarify

the pathogenesis of axial symptoms after laminoplasty. SUMMARY OF BACKGROUND

DATA: Outcome of the cervical surgery is evaluated on neurologic status alone; axial symptoms

after laminoplasty rarely have been investigated. Such symptoms, however, are often severe

enough to interfere with a person's daily activity. METHODS: Ninety-eight patients had surgery

for their disability secondary to cervical spondylotic myelopathy. Of those patients, 72 had

laminoplasty, and 26 had anterior interbody fusion. The presence or absence of axial symptoms

was investigated before and after surgery. The duration, severity, and laterality of symptoms were

also recorded. RESULTS: The prevalence of postoperative axial symptoms was significantly

higher after laminoplasty than after anterior fusion (60% vs. 19%; P < 0.05). In 18 patients

(25%) from the laminoplasty group, the chief complaints after surgery were related to axial

symptoms for more than 3 months, whereas in the anterior fusion group, no patient reported

having such severe pain after surgery. CONCLUSIONS: The prevalence and severity of axial

symptoms after laminoplasty proved to be higher and more serious than has been believed. Such

symptoms should be considered in the evaluation of the outcome of cervical spinal surgery.

Related Articles, Books, LinkOut

Postural imbalance and vibratory sensitivity in patients with idiopathic scoliosis: implications for treatment.

Byl NN, Holland S, Jurek A, Hu SS

J Orthop Sports Phys Ther 1997 Aug;26(2):60-8

University of California, San Francisco, USA.

Sporadic research reports of decreased proprioception and balance problems have been

reported in subjects with idiopathic scoliosis, yet these sensory motor deficits have not been

addressed in conservative clinical management programs. The purpose of this study was to

compare both balance reactions and vibratory sensitivity (as an estimate of proprioception) in

patients with idiopathic scoliosis (N = 24) and age-matched controls (N = 24). Balance was

measured by the ability to pass a series of simple static and complex sensory-challenged balance

tasks. Vibratory thresholds were measured with the Bio-Thesiometer at the cervical spine, wrist,

and foot. Compared with age-matched controls, regardless of curve severity or spinal fusion, the

subjects with idiopathic scoliosis had similar simple static balance responses when the

somatosensory system was stable (with or without vision or head turning), but they were

significantly more likely to fail the complex, sensory-challenged balance tasks when the

somatosensory system was challenged by an unstable position of the feet, particularly when the

eyes were closed. The vibratory thresholds were similar in subjects with scoliosis and their

age-matched controls, but individuals with moderate to severe scoliosis (> 25 degrees) had

significantly higher vibratory thresholds than those with mild curves. These findings suggest there

may be problems with postural righting in patients with idiopathic scoliosis, particularly when the

balance task challenges the vestibular pathways. Although vibration sensitivity did not distinguish

normal healthy individuals from individuals with idiopathic scoliosis, those with more severe

scoliotic curves appear to have a high threshold to vibration. These balance and vibratory

differences could either be interpreted as etiologic risk factors or as consequences of spinal

asymmetry. In either case, given that curves can continue to progress even into the adult years,

improving the ability to right the body with gravity could help maintain the balance of the spine

despite structural asymmetry.

PMID: 9243403, UI: 97387370

Kinematics of cervical spine injury. A functional radiological hypothesis.

Penning L

Eur Spine J 1995;4(2):126-32

Department of Diagnostic Radiology, University Hospital of Groningen AZG, The Netherlands.

This paper, based on functional radiological knowledge of normal cervical spine kinematics,

develops the hypothesis that compressive vertebral injury can be produced by abrupt reversal of

curve between hyperflexed and hyperextended parts of the cervical spine. Reversal of curve

occurs when the main vector of a compressive force passes between two centers of

flexion-extension motion. The hypothesis more clearly explains reverse dislocation of fractured

vertebrae than the current concept of Whitley and Forsyth of motion of the head through an arc.

The mechanism of injuries with characteristics of hyperflexion of one segment and hyperextension

of an adjacent segment, e.g., in certain types of hangman's fractures, is better understood. The

hypothesis is expected to be helpful in guiding experimental cervical spine injury, as it relates

direction of force to level and type of the resulting vertebral injury.

PMID: 7600151, UI: 95323521

support of breig

1: J Orthop Sports Phys Ther 1993 Mar;17(3):155-60

Reliability of measuring forward head posture in a clinical setting.

Garrett TR, Youdas JW, Madson TJ

Physical Therapy Program, Mayo School of Health-Related Sciences, Rochester, MN.

We believe there is a need to identify a practical method for determining

objective measurement of forward head posture. In our study, we determined the

within-tester and between-tester reliabilities for clinical measurements of

static, sitting, forward head posture using the cervical range of motion (CROM)

instrument. Repeated measurements were made using a standardized protocol on 40

patients seated in a standardized position. The seven testers had from 1 to 8

years of clinical experience. All measurements were recorded by the same

investigator. The intraclass correlation coefficient (ICC[1,1]) was used to

quantitate within-tester and between-tester reliability. Measurements of forward

head position performed by the same physical therapist had high reliability (ICC

= 0.93). Good reliability (ICC = 0.83) was demonstrated when different physical

therapists measured the forward head posture of the same patient. We concluded

that measurements of forward head posture made by physical therapists trained in

the correct use of the CROM instrument are reliable. This reliability is

important for determining the effectiveness of treatment programs. On the basis

of our data, the CROM instrument will assist clinicians in the objective

evaluation and reassessment of the patient population demonstrating forward head

posture.

PMID: 8472080, UI: 93230304

1: Spine 1998 Apr 15;23(8):921-7

The correlation between surface measurement of head and neck posture and the

anatomic position of the upper cervical vertebrae.

Johnson GM

School of Physiotherapy, University of Otago, Dunedin, New Zealand.

STUDY DESIGN: Repeated measurements were made of surface postural angles

registering the relative positions of the head and neck in photographs and of

angles of the upper cervical vertebrae recorded in lateral cephalometric

radiographs in the same subjects. For all registrations, subjects assumed the

natural head rest position. OBJECTIVES: To examine the correlation between

external measurement of head and neck posture and the anatomic positions of the

upper four cervical vertebrae. SUMMARY OF BACKGROUND DATA: Interpretation of

surface cervical posture measurement is confounded by lack of knowledge about

the extent of the underlying compensatory adjustments among the upper cervical

vertebrae that may accompany variation in head and neck posture. The correlation

between surface measurement and postural characteristics of the upper cervical

spine has not been reported to date. METHODS: The association between a set of

angles describing the anatomic position of the four upper cervical vertebrae on

lateral cephalometric radiographs and a surface measurement of head and neck

posture, the craniovertebral angle, was studied in 34 young adult women aged

between 17.2 and 30.5 years, mean age, 24.5 years. Anatomic positions of the

upper four cervical vertebrae were expressed by angles relative to the true

vertical or horizontal. Surface angles registering head and neck position for

each subject were obtained from photographs recorded on two occasions. RESULTS:

No strong correlation could be established between the angles taken from the

lateral cephalometric radiographs measuring the extent of upper cervical

lordosis, orientation of the atlas, vertebral inclination, or odontoid process

tilt and surface angles recording head and neck position. This finding was

attributed principally to the much greater positional variability demonstrated

within the upper cervical spine when compared with the surface measurements of

head and neck position. CONCLUSION: Anatomic alignment of the upper cervical

vertebrae cannot be inferred from variation in surface measurement of head and

neck posture. This is the case even in those people identified with more extreme

head and neck postural tendencies.

PMID: 9580960, UI: 98242061

1: Spine 1996 Nov 1;21(21):2435-42

The effect of initial head position on active cervical axial rotation range of

motion in two age populations.

Walmsley RP, Kimber P, Culham E

School of Rehabilitation Therapy, Queen's University, Kingston, Ontario, Canada.

STUDY DESIGN: This study analyzed cervical axial rotation initiated from five

different starting positions in asymptomatic subjects. The results were analyzed

to ascertain if rationale for certain clinical assessment methods could be

justified. SUMMARY OF BACKGROUND DATA: In the assessment of the cervical spine,

many clinicians use assessment techniques that propose to isolate anatomic

structures by using various permutations and combinations of the three gross

rotational movements, for example, evaluation of axial rotation in flexion and

extension. OBJECTIVES: The primary purpose of this study was to compare the

magnitude of cervical axial rotation when started from neutral, flexion,

extension, protraction, and retraction, and the protraction-retraction range of

motion also was determined. METHODS: Two groups of 30 subjects, one group aged

18-30 years and the other group aged 50-65 years and stratified by gender,

participated in the study. The 3Space Tracker system (Polhemus, A Kaiser

Aero-space and Electronics, Co., Colchester, VT), art electromagnetic tracking

device, was used to determine the angular and linear position of the head

relative to the sternum by detecting the position and orientation of two sensors

attached to the forehead and sternum. RESULTS: Analysis of variance of the data

revealed a statistically significant difference (p < 0.05) in axial rotation

between all of the five starting positions. The younger age group demonstrated

greater range of motion when rotation was initiated from neutral and extension,

whereas the older group had greater range when the motion was initiated from

protraction, retraction, and flexion. CONCLUSIONS: The results suggest that

varying the starting sagittal head position may affect the anatomic structures

involved in restraining axial rotation. This supports the clinical approach to

range of motion assessment in combined movement patterns.

PMID: 8923628, UI: 97082392

Incidence of common postural abnormalities in the cervical, shoulder, and

thoracic regions and their association with pain in two age groups of healthy

subjects.

Griegel-Morris P, Larson K, Mueller-Klaus K, Oatis CA

1: Phys Ther 1992 Jun;72(6):425-31

Philadelphia Institute for Physical Therapy, PA 19104.

The purposes of this study were to identify the incidence of postural

abnormalities of the thoracic, cervical, and shoulder regions in two age groups

of healthy subjects and to explore whether these abnormalities were associated

with pain. Eighty-eight healthy subjects, aged 20 to 50 years, were asked to

answer a pain questionnaire and to stand by a plumb line for postural assessment

of forward head, rounded shoulders, and kyphosis. Subjects were divided into two

age groups: a 20- to 35-year-old group (mean = 25, SD = 63) and a 36- to

50-year-old group (mean = 47, SD = 2.6). Interrater and intrarater reliability

(Cohen's Kappa coefficients) for postural assessment were established at .611

and .825, respectively. Frequency counts revealed postural abnormalities were

prevalent (forward head = 66%, kyphosis = 38%, right rounded shoulder = 73%,

left rounded shoulder = 66%). No relationship was found between the severity of

postural abnormality and the severity and frequency of pain. Subjects with more

severe postural abnormalities, however, had a significantly increased incidence

of pain, as determined by chi-square analysis (critical chi 2 = 6, df = 2, P

less than .05). Subjects with kyphosis and rounded shoulders had an increased

incidence of interscapular pain, and those with a forward-head posture had an

increased incidence of cervical, interscapular, and headache pain.

PMID: 1589462, UI: 92270665

1: J Manipulative Physiol Ther 1999 Jan;22(1):26-8

The ability to reproduce the neutral zero position of the head.

Christensen HW, Nilsson N

Nordic Institute of Chiropractic & Clinical Biomechanics, Odense, Denmark.

OBJECTIVE: To determine how precisely asymptomatic subjects can reproduce a

neutral zero position of the head. STUDY DESIGN: Repeated measures of the active

cervical neutral zero position. SETTING: Institute of Medical Biology (Center of

Biomechanics) at Odense University. PARTICIPANTS: Thirty-eight asymptomatic

students from the University of Odense, male/female ratio 20:18 and mean age

24.3 years (range, 20 to 30 years). INTERVENTION: Measurements of the location

of the neutral zero head position by use of the electrogoniometer CA-6000 Spine

Motion Analyzer. Each subject's neutral zero position with eyes closed was

measured 3 times. The device gives the localization of the neutral zero as

coordinates in 3 dimensions (x, v, z) corresponding to the 3 motion planes.

RESULTS: The mean difference from neutral zero in 3 motion planes was found to

be 2.7 degrees in the sagittal plane, 1.0 degree in the horizontal plane, and

0.65 degree in the frontal plane. CONCLUSION: We found that young adult

asymptomatic subjects are very good at reproducing the neutral zero position of

the head. This suggests the existence of some advanced neurologic control

mechanisms.

Publication Types:

Clinical trial

PMID: 10029946, UI: 99154208

1: Spine 1997 Apr 15;22(8):865-8

Ability to reproduce head position after whiplash injury.

Loudon JK, Ruhl M, Field E

Department of Physical Therapy Education, University of Kansas Medical Center,

Kansas City, USA.

STUDY DESIGN: A two-group design with repeated measures. OBJECTIVES: To

determine if there is loss of the ability to reproduce target position of the

cervical spine individuals who have sustained a whiplash injury. SUMMARY OF

BACKGROUND DATA: The ability to sense position is a prerequisite for functional

movement. Injury may have a deleterious effect on this ability, resulting in

inaccurate positioning of the head and neck with respect to the body coordinates

and to the environment. METHODS: Eleven subjects with history of whiplash injury

(age, 42 +/- 8.7 years) and 11 age-matched asymptomatic subjects (age, 43 +/-

3.1 years) participated in the study. Effects of whiplash injury on the ability

to replicate a target position of the head were assessed. Maximum rotation of

the neck and ability to reproduce the target angle were measured using a

standard cervical range-of-motion device. Subjects' perception of "neutral"

position was also assessed. RESULTS: Analysis of variance indicated the whiplash

subjects were less accurate in reproducing the target angle than were control

subjects. These whiplash subjects tended to overshoot the target. In addition,

the subjects in the whiplash group were often inaccurate in their assessment of

neutral position. CONCLUSIONS: Subjects who have experienced a whiplash injury

demonstrate a deficit in their ability to reproduce a target position of the

neck. These data are consistent with the hypothesis that these subjects possess

an inaccurate perception of head position secondary to their injury. This study

has implications for the rehabilitation of individuals with whiplash injury.

PMID: 9127919, UI: 97273529

1: Acta Odontol Scand 1989 Apr;47(2):105-9

Natural head position recording on frontal skull radiographs.

Huggare J

Institute of Dentistry, University of Oulu, Finland.

This paper sets out to evaluate the variability and reproducibility of frontal

head position in healthy young adults. Two posteroanterior skull radiographs of

22 dental students and 2 frontal photographs of these and 24 other students,

taken at a 1-week interval, were analyzed with regard to head position and

cervical spine inclination. Head position varied in the range of +/- 5 degrees

with regard to the vertical. The cervical spine was more often inclined to the

right than to the left. The reproducibility of the head position with regard to

the craniovertical angle was 1.15 degrees and that of the craniocervical and

cervicohorizontal angles 0.93 degrees and 1.45 degrees, respectively. Any

deviation in the frontal head position tended to be spontaneously corrected on

looking in a mirror. It is concluded that the frontal head position is slightly

more accurately reproducible than the sagittal head position. The use of a

mirror in front of the patient when recording the frontal natural head position

is not to be recommended.

PMID: 2718757, UI: 89244136

1: J Orthop Res 1992 Mar;10(2):217-25

Trunk positioning accuracy in children 7-18 years old.

Ashton-Miller JA, McGlashen KM, Schultz AB

Department of Mechanical Engineering and Applied Mechanics, University of

Michigan, Ann Arbor 48109-2125.

Trunk proprioception was measured in 253 healthy children 7-18 years of age

using infrared markers placed on the back of the head and on the skin over the

T1, T8, and S1 spinous processes. The children were tested for their accuracy in

sensing return of the head and trunk to a centered, neutral position in the

frontal plane. Whole-body sway was also quantified during 10 s of relaxed

standing by measuring mean amplitudes of trunk marker and foot center of

pressure (CP) movements. The results show that trunk positioning accuracy

improved significantly with age (p = 0.000). Subjects could position their trunk

in the frontal plane to within a mean (+/- SD) of 2.5 (+/- 1.1) and 0.9 (+/-

0.6) degrees of the neutral position at ages 7 and 18 years, respectively. No

statistically significant gender differences were found. At every age trunk

positioning accuracy was diminished in the presence of a continuous external

trunk moment (equivalent to 0.01 x body weight x height), although not

significantly so. Neither mean trunk sway nor CP amplitudes were significantly

correlated with age or sex. The overall results suggest that spine

decompensation is only abnormal when it exceeds 20 mm in healthy children and

adolescents.

PMID: 1740740, UI: 92156965

1: J Orthop Res 1991 Jul;9(4):576-83

Trunk positioning accuracy in the frontal and sagittal planes.

McGlashen K, Ashton-Miller JA, Green M, Schultz AB

Department of Mechanical Engineering and Applied Mechanics, University of

Michigan, Ann Arbor 48109-2125.

The accuracy with which the head and spine could be positioned in the frontal

and sagittal planes relative to the pelvis was measured and compared in ten

healthy adult males. Subjects were tested with eyes closed, while standing with

their pelvis externally restrained. The positions of markers, attached to the

back of the head and over each of the T1, T6, T11, and L3 spinous processes,

were measured to the nearest mm using strain-gaged flexible beam transducers.

Subjects were tested for their accuracy in sensing return of the trunk to an

initial neutral position under different test conditions. Results showed that

positioning was 16-45% more accurate in the frontal than in the sagittal plane,

although the difference did not reach statistical significance. T1 could be

centered to within 7 and 10 mm in the frontal and sagittal planes, respectively.

No significant differences were found between active and passive positioning

accuracies. Presence of an external trunk moment did not significantly affect

trunk positioning accuracy, although it systematically caused overshoot of the

neutral position. Lastly, lateral trunk shifts exceeding 12 mm may be classified

as abnormal in young adults.

PMID: 2045984, UI: 91259346

1: J Manipulative Physiol Ther 1998 Jul-Aug;21(6):388-91

The relationship between posture and curvature of the cervical spine.

Visscher CM, de Boer W, Naeije M

Department of Oral Function, Academic Centre for Dentistry, Amsterdam, The

Netherlands.

OBJECTIVE: To study the relationship between posture and curvature of the

cervical spine in healthy subjects. SUBJECTS: The study was composed of 54

healthy students (25 men and 29 women) aged 20-31 yr with a mean age of 24.7 yr.

METHODS: Lateral radiographs were taken of the head and cervical spine of the

subjects while standing in a neutral position. Cervical spine posture was

quantified by the angle of a reference line, composed of reference points of the

upper six cervical vertebrae, with the horizontal axis. The curvature of the

cervical spine was classified visually as lordotic, straight or reversed.

RESULTS: A relationship was found between posture and curvature of the cervical

spine (p = .006); a more forward posture of the cervical spine was related to a

partly reversed curvature; and a more upright posture was related to a lordotic

curvature. Moreover, men more often exhibited a straight curvature, and women

more often exhibited a partly reversed curvature. CONCLUSION: The curvature of

the cervical spine is related to the subject's posture and gender.

PMID: 9726065, UI: 98394128

Erector spinae lever arm length variations with changes in spinal curvature.

Tveit P, Daggfeldt K, Hetland S, Thorstensson A

Spine 1994 Jan 15;19(2):199-204

Magnetic resonance imaging was used to study the effect of different curvatures in the lumbar

spine on lever arm lengths of the erector spinae musculature. Eleven subjects were instructed to

simulate static lifts while lying supine in a magnetic resonance camera with the lumbar spine either

in kyphosis or lordosis. A sagittal image of the spine was obtained to analyze the lumbosacral

angle and to guide the imaging of transverse sections through each disc (L1/L2 to L5/S1). Images

were analyzed for lever arm lengths of the erector spinae muscle (ES) and the erector spinae

aponeurosis (ESA), the latter functioning as a tendon for superiorly positioned ES muscle

portions. The lumbosacral angle (between superior surfaces of S1 and L4) averaged 44 degrees

in the lordosed, 26 degrees in the kyphosed and 41 degrees in a neutral supine position. In

lordosis, the lever arm lengths were significantly longer than in kyphosis for all levels, averaging

60-63 mm (ES) and 82-86 mm (ESA). The corresponding values for kyphosis were 49-57 mm

(ES) and 67-77 mm (ESA), respectively. Thus, there was a considerable effect (10-24%) of

lumbar curvature on lever arm lengths for the back extensor muscles. The change in leverage will

affect the need for extensor muscle force and thus the magnitude of compression in the lumbar

spine in loading situations such as lifting.

Commonly adopted postures and their effect on the lumbar spine.

Dolan P, Adams MA, Hutton WC

Spine 1988 Feb;13(2):197-201

Polytechnic of Central London, England.

The activity of the erector spinae muscles and the changes in lumbar curvature were measured in

11 subjects in a range of commonly adopted postures to see if there were any consistent trends.

Surface electrodes were used to measure back muscle activity and lumbar curvature was

measured using electronic inclinometers. The results showed that many commonly adopted

postures reduced the lumbar lordosis when compared with erect standing or sitting, even at the expense of increasing the back muscle activity.

The effects of flexion on the geometry and actions of the lumbar erector spinae.

Macintosh JE, Bogduk N, Pearcy MJ

Spine 1993 Jun 1;18(7):884-93

Faculty of Medicine, University of Newcastle, Australia.

A modeling study was undertaken to determine the effects of flexion on the forces exerted by the

lumbar back muscles. Twenty-nine fascicles of the lumbar multifidus and erector spinae were

plotted onto tracings of radiographs of nine normal volunteers in the flexion position. Moment

arms and force vectors of each fascicle were calculated. The model revealed that moment arms

decreased slightly in length resulting in no more than an 18% decrease in maximum extensor

moments exerted across the lumbar spine. Compression loads were not significantly different

from those generated in the upright posture. However, there were major changes in shear forces,

in particular a reversal from a net anterior to a net posterior shear force at the L5/S1 segment.

Flexion causes substantial elongation of the back muscles, which must therefore reduce their

maximum active tension. However, if increases in passive tension are considered it emerges that

the compression forces and moments exerted by the back muscles in full flexion are not

significantly different from those produced in the upright posture.

Lumbar lordosis. Effects of sitting and standing.

Lord MJ, Small JM, Dinsay JM, Watkins RG

Spine 1997 Nov 1;22(21):2571-4

Kerlan-Jobe Orthopaedic Clinic, Inglewood, California, USA.

STUDY DESIGN: The effect of sitting versus standing posture on lumbar lordosis was studied

retrospectively by radiographic analysis of 109 patients with low back pain. OBJECTIVE: To

document changes in segmental and total lumbar lordosis between sitting and standing

radiographs. SUMMARY OF BACKGROUND DATA: Preservation of physiologic lumbar

lordosis is an important consideration when performing fusion of the lumbar spine. The

appropriate degree of lumbar lordosis has not been defined. METHODS: Total and segmental

lumbar lordosis from L1 to S1 was assessed by an independent observer using the Cobb angle

measurements of the lateral radiographs of the lumbar spine obtained with the patient in the sitting

and standing positions. RESULTS: Lumbar lordosis averaged 49 degrees standing and 34

degrees sitting from L1 to S1, 47 degrees standing and 33 degrees sitting from L2 to S1, 31

degrees standing and 22 degrees sitting from L4 to S1, and 18 degrees standing and 15 degrees

sitting from L5 to S1. CONCLUSION: Lumbar lordosis while standing was nearly 50% greater

on average than sitting lumbar lordosis. The clinical significance of this data may pertain to: 1) the

known correlation of increased intradiscal pressure with sitting, which may be caused by this

decrease in lordosis; 2) the benefit of a sitting lumbar support that increases lordosis; and 3) the

consideration of an appropriate degree of lordosis in fusion of the lumbar spine.

Effect of patient position on the sagittal-plane profile of the thoracolumbar spine.

Wood KB, Kos P, Schendel M, Persson K

: J Spinal Disord 1996 Apr;9(2):165-9

Department of Orthopaedic Surgery, University of Minnesota, Minneapolis 55455, USA.

Although the normal sagittal profile of the thoracolumbar spine has been described, this has been

obtained primarily by using young individuals standing. We sought to describe the sagittal profile

of the thoracolumbar spine in an older population in the supine cross-table lateral position

compared with that standing. We enrolled 50 volunteers with no history of back pain or spine

deformity and 50 matched subjects with mechanical back pain (LBP) only. Lateral radiographs

of the thoracolumbar spine (T10-S1) in both standing and cross-table supine positions were

obtained. Lordosis from L1 to S1, kyphosis from T10 to L1, and the changes seen moving from

the supine position to standing were calculated. There were few differences comparing the two

groups in either the standing or cross-table supine position, or when changing positions. Within

each group, however, there were small, but significant, differences in the midlumbar and

thoracolumbar spine when comparing supine versus standing. Both asymptomatic individuals and

those with a history of LBP demonstrated similar small but statistically significant increases in

lumbar lordosis and thoracolumbar kyphosis when standing versus supine. The clinical

significance of these findings remains to be determined.

Kinetic potential of the lumbar trunk musculature about three orthogonal orthopaedic axes in extreme postures.

McGill SM

Spine 1991 Jul;16(7):809-15

Department of Kinesiology, University of Waterloo, Ontario, Canada.

Many studies have examined the mechanics of the lumbar spine in various planes, but only a

limited number of three-dimensional investigations have been reported. Analysis of the low back

during complex, dynamic postures demands rigorous representation of the trunk musculature. The

data of this study demonstrated the force and torque contributions of approximately 50 laminas of

various trunk muscles to flexion-extension, lateral bending, and axial twisting torque at the L4-L5

joint. This analysis was conducted with the spine in an upright standing posture and when fully

flexed (60 degrees), laterally bent (25 degrees), and axially twisted (10 degrees) together with

two examples of combined postures. Maximum moment potential, muscle length excursions, and

the resultant compressive, anteroposterior shear, and lateral shear forces on the joint were also

computed. The results indicate that the position of the vertebrae and their orthopaedic axes,

which are a function of spinal posture, are an important factor in the reasonable determination of

joint compressive, lateral shear, and anteroposterior shear loads. Muscle length changes that

exceeded 20% of their respective length during upright standing were not observed during a full

axial twist, but were observed in portions of the abdominal obliques during lateral bending, and in

some extensors during full flexion. Extreme postures tended to change the torque potential of

some muscles and influence joint load. Various portions of erector spinae were observed to have

appreciable potential to generate torque about all three orthopaedic axes. This observation

supports the notion held by some therapists that conditioning of the erector spinae is of utmost

importance.

On neck muscle activity and load reduction in sitting postures. An electromyographic and biomechanical study with applications in ergonomics and rehabilitation.

Schuldt K

Scand J Rehabil Med Suppl 1988;19:1-49

Department of Physical Medicine and Rehabilitation Karolinska Institute, Stockholm, Sweden.

In this study of the biomechanics and muscular function of the cervical spine, skilled women

workers simulated standardized electromechanical assembly work in eight sitting postures.

Normalized electromyography was used to quantify activity in neck-and-shoulder muscles. With

the whole spine flexed, muscle activity in the cervical erector spinae, trapezius and thoracic

erector spinae muscles was higher than when the whole spine was straight and vertical. The

posture with the trunk slightly inclined backward and neck vertical gave the lowest activity levels.

Flexed neck compared to vertical neck gave higher activity in the cervical erector spinae. Work

with abducted arm gave high neck muscle activity. Work postures can thus be optimized to

diminish neck muscle load. Two ergonomic acids were studied during the work cycle. Elbow

support reduced the activity in the trapezius and thoracic erector spinae/rhomboids muscles in the

posture with the whole spine flexed and in the posture with the whole spine vertical. Arm

suspension gave mainly similar reduction in these postures, and also a reduction in the cervical

erector spinae. In the position with the trunk slightly inclined backward, arm suspension gave a

reduction in the trapezius. These findings indicate that arm support or arm suspension can be used

to reduce neck muscle load. Three methodological studies related to neck muscle load and

normalization were included. 1) Examination of the effect of different isometric maximum test

contractions on neck muscles showed that all contractions activated all muscles studied, including

those on the contralateral side, to some extent and at various levels. The highest frequency of

attained maximum levels was: for neck extension, in cervical erector spinae; for cervical spinae

lateral flexion, in splenius and levator scapulae; for arm abduction, in trapezius, and, for shoulder

elevation and scapular retraction/elevation, in thoracic erector spinae/rhomboids. Proximal

resistance gave higher activity than distal. 2) The relationship between EMG activity and muscular

moment was studied in women during submaximal and maximum isometric neck extension. The

relationship found was non-linear, with greater increase in activity at high moments in the

posterior neck muscles studied. The slightly flexed cervical spine position induced a higher level

of activity in erector spinae cervicalis than did the neutral position for a given relative muscular

moment. 3) Muscular activity was related to cervical spine position during maximum isometric

neck extension. Peak activity in the cervical erector spinae was found in the slightly flexed

lower-cervical spine position.

Intensity and character of pain and muscular activity levels elicited by maintained extreme flexion position of the lower-cervical-upper-thoracic spine.

Harms-Ringdahl K, Ekholm

J Scand J Rehabil Med 1986;18(3):117-26

The aim of this study was to find out whether maintained extreme flexion position of the lower-cervical-upper-thoracic spine in a sitting posture could induce pain, and thus possibly play a role in work related disorders with cervico-brachial pain. Ten healthy subjects assessed pain intensity of experimentally-induced pain on a Visual Analogue Scale (VAS). The quality and location of the pain was indicated on a drawing of the body. The load moment induced by the weight of the head-and-neck was calculated. The EMG activity levels were recorded from the splenius, thoracic erector spinae-rhomboid, and descending part of trapezius muscles. This posture, which resembles the posture in some common work, caused pain in all subjects. The pain was experienced within 15 min, increased with time, disappeared within 15 min after the end of provocation, but was again experienced by nine subjects the same evening or next morning and lasted up to four days. The primary location was in the dorsal part of the lower cervical and upper thoracic spine; three subjects also reported pain in the arms and one in the head. The recorded EMG levels were very low, but they increased somewhat during provocation. It is suggested that thorough recordings of work postures should be included in ergonomic analyses to provide a basis for the avoidance of such positions which might provoke pain.

Influence of head position on dorsal neck muscle efficiency.

Mayoux-Benhamou MA, Revel M

Electromyogr Clin Neurophysiol 1993 Apr-May;33(3):161-6

Department of rehabilitation, Hopital Cochin, Paris, France.

The aim of this study was to assess the influence of head position on dorsal neck muscle efficiency in the sagittal plane. Fifteen subjects participated. The EMG versus isometric extension moment of dorsal neck muscles was studied in neutral (with subject gazing on a horizontal plane), cervical flexed, and cervical extended positions. A vectorial construction was created by means of photographs to calculate the extension moment which balances measured pulling force and gravitational force in isometric conditions. The maximum extension was highest in neutral position. The EMG/moment relationship was non-linear. The ratio between the EMG and the generated moment differed significantly in the three positions (p < 0.01) and was lower in neutral position. These results demonstrate the influence of head position on dorsal neck muscle efficiency; muscles appeared most efficient in neutral position. Muscle length, depending on head position, is probably the main influencing factor.

PMID: 8495657, UI: 93265827

Genioglossi muscle activity in response to changes in anterior/neutral head posture.

Milidonis MK, Kraus SL, Segal RL, Widmer CG

Am J Orthod Dentofacial Orthop 1993 Jan;103(1):39-44

Orthopaedic Clinical Specialist, Rehab Services, Akron City Hospital, Ohio.

Clinicians have acknowledged swallowing, tongue activity, and head posture as interdependent variables that must be concurrently examined. The purpose of this study was to evaluate genioglossus activity during swallowing, rest, and maximal tongue protrusion in two head positions (HPs) with a noninvasive recording device. Eight Angle Class I subjects were evaluated. Repeated measures were performed in a single session to record surface intraoral electromyographic (EMG) activity of the genioglossus muscles. Head position was measured in angular degrees from photographs. Three variables were measured in both the neutral-head position (NHP) and anterior-head position (AHP): (1) duration of genioglossus EMG during swallowing, (2) genioglossus EMG with the tongue at rest, and (3) genioglossus EMG during maximal isometric tongue protrusion. A Wilcoxin matched-pair signed-rank statistic was used for EMG analysis, and a paired sample t test statistic was used for head posture analysis. The angles measured for NHP and AHP within each subject were significantly different verifying two different head positions. Duration of swallowing was not significantly different between head positions. Resting genioglossus EMG and maximal isometric genioglossus EMG were statistically greater in the AHP. The data suggest that head positional changes may have an effect on genioglossus muscle activation thresholds. However, small differences in resting EMG activity between head positions suggests that the clinical significance needs further investigation.

Influence of muscle morphometry and moment arms on the moment-generating capacity of human neck muscles.

Vasavada AN, Li S, Delp SL

Spine 1998 Feb 15;23(4):412-22

Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA.

STUDY DESIGN: The function of neck muscles was quantified by incorporating experimentally measured morphometric parameters into a three-dimensional biomechanical model. OBJECTIVE: To analyze how muscle morphometry and moment arms influence moment-generating capacity of human neck muscles in physiologic ranges of motion. SUMMARY OF BACKGROUND DATA: Previous biomechanical analyses of the head-neck system have used simplified representations of the musculoskeletal anatomy. The force- and moment-generating properties of individual neck muscles have not been reported. METHODS: A computer graphics model was developed that incorporates detailed neck muscle morphometric data into a model of cervical musculoskeletal anatomy and intervertebral kinematics. Moment arms and force-generating capacity of neck muscles were calculated for a range of head positions. RESULTS: With the head in the upright neutral position, the muscles with the largest moment arms and moment-generating capacities are sternocleidomastoid in flexion and lateral bending, semispinalis capitis and splenius capitis in extension, and trapezius in axial rotation. The moment arms of certain neck muscles (e.g., rectus capitis posterior major in axial rotation) change considerably in the physiologic range of motion. Most neck muscles maintain at least 80% of their peak force-generating capacity throughout the range of motion; however, the force-generating apacities of muscles with large moment arms and/or short fascicles (e.g., splenius capitis) vary substantially with head posture. CONCLUSION: These results quantify the contributions of individual neck muscles to moment-generating capacity and demonstrate that variations in force-generating capacity and moment arm throughout the range of motion can alter muscle moment-generating capacities.

[Electromyographic study on the effects of head position to head and neck muscles].

Omae T, Inoue S, Saito O, Ishii H, Ishigaki S, Okuda T, Nakamura T, Akanishi M, Maruyama T

Nippon Hotetsu Shika Gakkai Zasshi 1989 Apr;33(2):352-8

The purpose of this study is to reveal the relationship between the head position, and the neck

and head muscles. At 4 head positions, the activities of masseter, anterior temporal, anterior

digastric, sternocleidomastoid and trapezius muscle of ten normal subjects standing straight were

investigated electromyographically with surface electrodes during voluntary maximal clenching in

centric occlusion. Head positions were right tilting, left tilting, up-right and natural head position.

The results obtained were as follows; 1. During head tilting, the activities of anterior digastric and sternocleidomastoid muscle on the tilting side were increased, the activities of masseter and trapezius muscle on the opposite side of the tilting side were increased, the activity of the anterior temporal muscle did not vary from the activity during up-right head position. 2. During natural head position, only the activity of sternocleidomastoid muscle on the natural tilting side was increased.

Selective electromyography of dorsal neck muscles in humans.

Mayoux-Benhamou MA, Revel M, Vallee C

Brain Res 1997 Feb;113(2):353-60

Laboratoire d'Exploration de l'Appareil Locomoteur et d'Evaluation du Handicap, Universite Paris V, Hopital Cochin, France.

The patterns of activation of splenius capitis, semispinalis capitis, transversospinalis, and levator

scapulae muscles were studied during various head-neck positions, movements, and isometric tests in 19 healthy human subjects. Myoelectric activities were recorded with intramuscular bipolar wire electrodes. Cervical computerized tomography of each subject was performed before the electromyography session in order to guide electrode insertion. Head motion was recorded using an electromechanical device. This report demonstrates that head motion results from a complex interaction of active muscular forces, passive ligamentous forces, and gravity. Splenius capitis has two main functions, i.e., cervical extension and ipsilateral rotation. Semi spinalis capitis and the transversospinalis are mainly extensors, and levator scapulae acts primarily on the shoulder girdle. Splenius capitis, semispinalis capitis, and transversospinalis play a subordinate part in ipsilateral tilting. In addition, most subjects' semispinalis capitis were gradually recruited during ipsilateral rotation. No signal was detected from the transversospinalis during rotation tests.

Can stress-related shoulder and neck pain develop independently of muscle activity?

Vasseljen O Jr, Westgaard RH

Pain 1996 Feb;64(2):221-30

Division of Organization and Work Science, Norwegian Institute of Technology, University of Trondheim, Norway.

A case-control designed was used to investigate associations and interactions between muscle activity measured by surface electromyography (EMG) in the upper trapezius muscle and subjectively reported risk factors in workers with and without shoulder and neck pain. EMG data were collected both in the workplace (indicating vocational muscle activity) and in a laboratory setting (indicating non-specific muscle activity). Women in manual (15 pairs) and office (24 pairs) work were included. The pairs were matched on age, gender and on current and historical work load, such as working hours, type and length of employment. Previous reports of this study have indicated that shoulder and neck myalgia was associated with increased muscle activity for the manual workers, and with psychological and psychosocial factors for the office workers. These risk factors were in the present report used as the basis for studying associations and interactions between muscle activity (1), psychological and psychosocial factors (2), and shoulder and neck pain (3). Subjectively reported or perceived general tension, a stress symptom presumed related to psychosocial and psychological factors, was previously found to be the strongest and only variable separating cases and controls in both work groups. In this paper, no relationship was found between perceived general tension and EMG variables for the office workers. For the manual workers a strong interaction was found; perceived general tension correlated positively with EMG variables for the controls, and negatively with EMG variables for the cases. It is hypothesised that the feeling of general tension represents a physiological activation response that may or may not include muscle fibre activation. This implies that pain provoked by psychosocial stress factors may not be mediated through increased muscle activity.

1: Int J Rehabil Res 1999 Sep;22(3):207-14

Treatment based on H-reflexes testing improves disability status in patients

with cervical radiculopathy.

Abdulwahab SS

Texas Woman's University School of Physical Therapy, Houston, USA.

BACKGROUND: Postural modification in patients with lumbosacral radiculopathy

either causes further H-reflex suppression, indicating increased root

compression, or it effects recovery, indicating decompression of the spinal

root. The posture that effects maximum recovery of the H-reflex amplitude is

called optimum spinal posture (OSP) and is suggested as a therapeutic exercise

to decompress the compromised nerve root. The focus of this study was to

identify the OSP that effects the maximum recovery of the flexor carpi radialis

(FCR) H-reflex and to study its effect on the disability status in patients with

cervical radiculopathy. SUBJECTS AND METHODS: Fourteen patients (46 +/- 12 y)

with confirmed symptoms of C7 radiculopathy for the previous 6 months

volunteered for the study. The FCR H-reflex was elicited by electrical

stimulation of the median nerve at the cubital fossa (0.5 ms, 0.2 pps at H-max).

Signals from the FCR muscle were recorded using a Cadwell 5200A EMG unit. The

FCR H-reflex was recorded in natural sitting position with the head in natural

position and in the OSP. Four traces of the H-reflex were recorded and averaged.

The disability status was evaluated, using the Neck Disability Index (NDI),

before exercising in the OSP and after 2 days of exercise in the OSP. DATA

ANALYSIS: Paired t-test and Spearman's correlation coefficients were used.

RESULTS: The H-reflex amplitude and latency were significantly different in the

OSP and with the head in a natural position (P < 0.004; P < 0.011). Larger

reflex amplitude and shorter latency were recorded in the OSP. The NDI scores

were considerably improved after exercising in the OSP (P < 0.001). Spearman's

correlation coefficient showed negative association between the H-reflex

amplitude and the NDI scores (r = -0.64 to -0.54; P < 0.05). CONCLUSION:

Exercising in the OSP increased the H-reflex amplitude and decreased latency of

the compromised cervical root. It resulted in decreasing the disability status

in this group of patients.

PMID: 10839674, UI: 20296484

1: J Vestib Res 1996 Nov-Dec;6(6):439-53

Effects of different treatments on postural performance in patients with

cervical root compression. A randomized prospective study assessing the

importance of the neck in postural control.

Persson L, Karlberg M, Magnusson M

Department of Neurosurgery, University Hospital, Lund, Sweden.

Patients with cervical root compression were used as a "model" to investigate

the possible importance of neck disorders and cervical sensory information in

postural control. We assessed postural performance with posturography before and

after treatment in 71 consecutive patients with MRI-verified cervical root

compression without medullary compression. The patients were randomized to

surgery (n = 22), physiotherapy (n = 24) or treatment with cervical collars (n =

25). There were no differences in postural performance or pain intensity between

the groups before treatment. After treatment, the surgery group manifested

significant improved postural performance and reduced neck pain scores, as

compared to the two conservative treatment groups, and their postural

performance had improved to the same level manifested by healthy controls. The

conservative treatment groups manifested no consistent significant changes in

postural performance or pain scores. Decreased muscular tension due to reduction

of cervical pain after surgery and normalization of cervical proprioception are

suggested as possible explanations of the improved postural control.

Publication Types:

Clinical trial

Randomized controlled trial

PMID: 8968971, UI: 97123724