Back Pain and the Vestibular

SystemBy: Jere Hess

Spine Natural curves

Anterior Cervical and Lumbar curvePosterior Thoracic curveGood posture maintains these curves

and the integrity of your spineBad posture puts stress on soft tissue

structures around the spine and can compromise the integrity of the spine leading to back pain.

Back pain Low back pain is the leading cause of disability in the United

States for people under 45 years of age 31 million Americans experience low-back pain at any given time One-half of all working Americans admit to having back pain

symptoms each year Americans spend at least $50 billion each year on back pain—

and that’s just for the more easily identified costs Experts estimate that as many as 80% of the population will

experience a back problem at some time in our lives

Vestibular System Equilibrium

Balance

Spatial orientation

Head & Eye coordination

Upright Posture

Innervated by Cranial Nerve VIII (Vestibulocochlear Nerve) Sensory Nerve

2 branches Vestibular and Cochlear

Cochlear Branch Axons from the organ of corti

Function is hearing

Vestibular Branch Axons from the semicircular canals, saccule, and utricle

Function is equilibrium

Primary organs Semicircular canals

Otolithic organs

Anatomy: Semi-circular Canals 3 semicircular canals “SCC” (One set in each inner ear)

Anterior (a.k.a superior), posterior, and horizontal (a.k.a lateral) Contains endolymphatic fluid Detect angular rotation of the head

By endolymphatic fluid stimulating stereocillia moving it towards or away from the kinocillium.

Collectively the anterior and posterior canals are called the vertical semicircular canals Detect flexion and extension of head in sagittal plane Nodding head to say “yes”

Horizontal Canal Detects rotation of head in transverse plane Rotating head to say “no”

Cupula A cupula is located at the end of each SCC in the ampulla

Anatomy: Otolithic Organs Detect Horizontal and Vertical displacement Primary Otolithic Organs

Saccule Responds to vertical displacement as in jumping rope

Utricle Responds to horizontal displacement Contains Ottoconia (calcium carbonate crystals ). Utricle is the only

place in the vestibular system that should contain ottoconia.

Anatomy: Vestibulospinal TractBelongs to the extrapyramidal system of CNS

Modulation/Regulation indirectly through ventral horns

Efferent Upper Motor Neuron

(one exception which will be covered later)

Pathways of the vestibular system among the oldest in our body Myelination of pathways occurs while we are in utero

Two sub pathways Lateral Vestibulospinal Tract Medial Vestibulospinal Tract

Lateral Vestibulospinal TractLocation?

Originates in Deiter’s nucleus of Pons Is located in lateral funiculus Ipsilateral projects down the spinal cord Runs the entire length of the spinal cord and terminates in laminae VII and VIII

Function? Maintains posture and balance

How? Excites interneurons of anti-gravity muscles Activates Extensor muscles of the spine and lower extremities

Medial Vestibulospinal Tract

Location?Originates Schwalbe's nucleusLocated in the anterior funiculusBilaterally projects down the spinal cordExtends to the caudal portion of the pons (only in cervical spine and

above)

Medial Vestibulospinal Tract cont.

Function #1 Provides cervical and scapular stability, posture, and

mobility. How?

Controls Neurons involved with C.N. XI (Accessory Nerve)

C.N XI Innervates the Traps and SCM Trapezius

Upper Traps: Extend Head and Neck/Elevate and upwardly rotate scapula

Middle Traps: Abduct Scapula

Lower Traps: Depress and upwardly rotate the scapula

SCM Unilaterally: laterally flexes head and neck to ipsilateral side and rotates

head and neck to contralateral side.

Bilaterally: Flexes the neck and assist to elevate the rib cage during inhalation.

Function #2 Keeps the eyes

“yoked” together during rapid acceleration and movement of the head which ultimately controls head and whole body orientation.

How? Superiorly

projects to paramedian pontine reticular formation which indirectly innervates C.N. III and C.N. VI

What does all of this mean? Majority of back pain treatments fall under two basic

categories: Mechanical Tx

Manual therapy, increase mm strength, mm endurance, mm imbalance, correcting LLD, surgery, etc…

Pain and lifestyle management Tx Injections, medications, modalities, ergonomics, and education, etc…

Back pain and posture are often treated as a mechanical unit and not a neuro-mechanical

Could strengthening the vestibular system correct the “mechanical structures” that lead to poor posture, spinal instability, leading to back pain?

Study 1 Abstract

There is evidence to implicate the role of the cervical spine in influencing postural control, however the underlying mechanisms are unknown. The aim of this study was to explore standing postural control mechanisms in older adults with neck pain (NP) using measures of signal frequency (wavelet analysis) and complexity (entropy). This cross-sectional study compared balance performance of twenty older adults with (age=70.3±4.0 years) and without (age=71.4±5.1 years) NP when standing on a force platform with eyes open and closed. Anterior-posterior centre-of-pressure data were processed using wavelet analysis and sample entropy. Performance-based balance was assessed using the Timed Up-and-Go (TUG) and Dynamic Gait Index (DGI). The NP group demonstrated poorer functional performance (TUG and DGI, p<0.01) than the healthy controls. Wavelet analysis revealed that standing postural sway in the NP group was positively skewed towards the lower frequency movement (very-low [0.10-0.39Hz] frequency content, p<0.01) and negatively skewed towards moderate frequency movement (moderate [1.56-6.25Hz] frequency content, p=0.012). Sample entropy showed no significant differences between groups (p>0.05). Our results demonstrate that older adults with NP have poorer balance than controls. Furthermore, wavelet analysis may reveal unique insights into postural control mechanisms. Given that centre-of-pressure signal movements in the very-low and moderate frequencies are postulated to be associated with vestibular and muscular proprioceptive input respectively, we speculated that, because NP demonstrate a diminished ability to recruit the muscular proprioceptive system compared to controls, they rely more on the vestibular system for postural stability.

Study 2 OBJECTIVE:

This review details the anatomy and interactions of the postural and somatosensory reflexes. We attempt to identify the important role the nervous system plays in maintaining reflex control of the spine and posture. We also review, illustrate, and discuss how the human vertebral column develops, functions, and adapts to Earth's gravity in an upright position. We identify functional characteristics of the postural reflexes by reporting previous observations of subjects during periods of microgravity or weightlessness.

BACKGROUND:

Historically, chiropractic has centered around the concept that the nervous system controls and regulates all other bodily systems; and that disruption to normal nervous system function can contribute to a wide variety of common ailments. Surprisingly, the chiropractic literature has paid relatively little attention to the importance of neurological regulation of static upright human posture. With so much information available on how posture may affect health and function, we felt it important to review the neuroanatomical structures and pathways responsible for maintaining the spine and posture. Maintenance of static upright posture is regulated by the nervous system through the various postural reflexes. Hence, from a chiropractic standpoint, it is clinically beneficial to understand how the individual postural reflexes work, as it may explain some of the clinical presentations seen in chiropractic practice.

METHOD:

We performed a manual search for available relevant textbooks, and a computer search of the MEDLINE, MANTIS, and Index to Chiropractic Literature databases from 1970 to present, using the following key words and phrases: "posture," "ocular," "vestibular," "cervical facet joint," "afferent," "vestibulocollic," "cervicocollic," "postural reflexes," "spaceflight," "microgravity," "weightlessness," "gravity," "posture," and "postural." Studies were selected if they specifically tested any or all of the postural reflexes either in Earth's gravity or in microgravitational environments. Studies testing the function of each postural component, as well as those discussing postural reflex interactions, were also included in this review.

DISCUSSION:

It is quite apparent from the indexed literature we searched that posture is largely maintained by reflexive, involuntary control. While reflexive components for postural control are found in skin and joint receptors, somatic graviceptors, and baroreceptors throughout the body, much of the reflexive postural control mechanisms are housed, or occur, within the head and neck region primarily. We suggest that the postural reflexes may function in a hierarchical fashion. This hierarchy may well be based on the gravity-dependent or gravity-independent nature of each postural reflex. Some or all of these postural reflexes may contribute to the development of a postural body scheme, a conceptual internal representation of the external environment under normal gravity. This model may be the framework through which the postural reflexes anticipate and adapt to new gravitational environments.

CONCLUSION:

Visual and vestibular input, as well as joint and soft tissue mechanoreceptors, are major players in the regulation of static upright posture. Each of these input sources detects and responds to specific types of postural stimulus and perturbations, and each region has specific pathways by which it communicates with other postural reflexes, as well as higher central nervous system structures. This review of the postural reflex structures and mechanisms adds to the growing body of posture rehabilitation literature relating specifically to chiropractic treatment. Chiropractic interest in tevaluate hese reflexes may enhance the ability of chiropractic physicians to treat and correct global spine and posture disorders. With the knowledge and understanding of these postural reflexes, chiropractors can spinal configurations not only from a segmental perspective, but can also determine how spinal dysfunction may be the ultimate consequence of maintaining an upright posture in the presence of other postural deficits. These perspectives need to be explored in more detail.

Study 3 Abstract INTRODUCTION: The differences in sagittal spino-pelvic alignment between adults with chronic low back pain (LBP) and the normal

population are still poorly understood. In particular, it is still unknown if particular patterns of sagittal spino-pelvic alignment are more prevalent in chronic LBP. The current study helps to better understand the relationship between sagittal alignment and low back pain.

MATERIALS AND METHODS: To compare the sagittal spino-pelvic alignment of patients with chronic LBP with a cohort of asymptomatic adults.

Sagittal spino-pelvic alignment was evaluated in prospective cohorts of 198 patients with chronic LBP and 709 normal subjects. The two cohorts were compared with respect to the sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), lumbar tilt (LT), lordotic levels, thoracic kyphosis (TK), thoracic tilt (TT), kyphotic levels, and lumbosacral joint angle (LSA). Correlations between parameters were also assessed.

RESULTS: Sagittal spino-pelvic alignment is significantly different in chronic LBP with respect to SS, PI, LT, lordotic levels, TK, TT

and LSA, but not PT, LL, and kyphotic levels. Correlations between parameters were similar for the two cohorts. As compared to normal adults, a greater proportion of patients with LBP presented low SS and LL associated with a small PI, while a greater proportion of normal subjects presented normal or high SS associated with normal or high PI.

CONCLUSION: Sagittal spino-pelvic alignment was different between patients with chronic LBP and controls. In particular, there was a

greater proportion of chronic LBP patients with low SS, low LL and small PI, suggesting the relationship between this specific pattern and the presence of chronic LBP.

Study 4 Abstract

STUDY DESIGN:

A prospective study of the sagittal standing posture of 766 adolescents.

OBJECTIVE:

To determine whether posture subgroups based on photographic assessment are similar to those used clinically and to previous, radiographically determined subgroups of sagittal standing posture, and whether identified subgroups are associated with measures of spinal pain.

SUMMARY OF BACKGROUND DATA:

Relatively little research has been performed toward a classification of subjects according to sagittal spinal alignment. Clinical descriptions of different standing posture classifications have been reported, and recently confirmed in a radiographic study. There is limited epidemiological data available to support the belief that specific standing postures are associated with back pain, despite plausible mechanisms. As posture assessment using radiographic methods are limited in large population studies, successful characterization of posture using 2-dimensional photographic images will enable epidemiological research of the association between posture types and spinal pain. METHODS.: Three angular measures of thoraco-lumbo-pelvic alignment were calculated from lateral standing photographs of subjects with retro-reflective markers placed on bony landmarks. Subgroups of sagittal thoracolumbar posture were determined by cluster analysis of these 3 angular measures. Back pain experience was assessed by questionnaire. The associations between posture subgroups and spinal pain variables were evaluated using logistic regression.

RESULTS:

Postural subtypes identified by cluster analysis closely corresponded to those subtypes identified previously by analysis of radiographic spinal images in adults and to those described clinically. Significant associations between posture subgroups and weight, height, body mass index, and gender were identified. Those adolescents classified as having non-neutral postures when compared with those classified as having a neutral posture demonstrated higher odds for all measures of back pain, with 7 of 15 analyses being statistically significant.

CONCLUSION:

Meaningful classifications exist for adolescent sagittal thoraco-lumbo-pelvic alignment, and these can be determined successfully from sagittal photographs. More neutral thoraco-lumbo-pelvic postures are associated with less back pain.

Study 5 Abstract

Context: Individuals with vestibular dysfunction are at increased risk for falling. In addition, vestibular dysfunction is associated with chronic pain, which could present a serious public health concern as approximately 43% of US adults have chronic pain.

Objective: To assess the incidence of vestibular dysfunction in patients receiving medication for chronic, spinal stenosis, HNP, spondylolisthesis, spondylosis, degenerative disc disease, or other underlying neurologic disorders and to determine associated follow-up therapeutic and diagnostic recommendations.

Methods: The authors conducted a retrospective medical record review of consecutive patients who were treated in their private neuroscience practice with medications for chronic pain or underlying neurologic disorders in 2011. All patients underwent a series of tests using videonystagmography for the assessment of vestibular function. Test results and recommendations for therapy and additional testing were obtained.

Results: Medical records of 124 patients (78 women, 46 men) were reviewed. Vestibular deficits were detected in 83 patients (66.9%). Patient ages ranged from 29 through 72 years, with a mean age of 50.7 years for women and 52.5 years for men. Physician-recommended therapy and follow-up testing were as follows: 32 patients (38.6%), neurologic examination and possible magnetic resonance (MR) imaging or computed tomography (CT) of the brain; 26 patients (31.3%), vestibular rehabilitation therapy only; 22 patients (26.5%), vestibular and related balance-function rehabilitation therapy, further neurologic examination, and possible MR imaging or CT; 2 patients (2.4%), balance-function rehabilitation therapy and specialized internal auditory canal high-magnification MR imaging or CT to assess for acoustic neuroma; and 1 patient (1.2%), specialized internal auditory canal high-magnification MR imaging or CT to evaluate for possible intracanalicular acoustic neuroma.

Conclusion: Patients being treated with medications for chronic pain or other underlying neurologic disorders (spinal stenosis, herniated nucleus pulposus, spondylolisthesis, spondylosis, degenerative disc disease may have a higher-than-average incidence of vestibular dysfunction. Baseline assessment and monitoring of the vestibular apparatus may be indicated for these patients.

Types of Vestibular Tx for back pain

Pt. must be able to tolerate; no Tx should further aggravate the back. Case to case basis

Vestibular gain: VORx1/VORx2 Challenge Horizontal canal: Transverse HTS Challenge Anterior/Posterior canal: Saggital HTS Linear acceleration: challenge utricle Verticle acceleration: challenge saccule EC: eliminates vision causing somatosensory and vestibular to increase function Changing surface/narrow BOS: causes vision and vestibular to increase function

Conclusion

Back pain is highly prevalent and most Tx is directed at a mechanical and/or pain modulation approach. Because of the ubiquitous nature of back pain, it is questionable how successful the medical industry is

at Tx back pain. There is no question vestibular functioning plays a significant role in posture.

There is a question as to whether or not postural deficiencies play a role in back pain. Could back pain be causing the poor posture?...Chicken and Egg?

Vestibular system plays a role in balance which could prevent falls leading to increased incidence of back pain.

Would focusing on strengthening the vestibular system be the answer to treating back pain? IMO, no. I do believe it could play a role in assisting mechanical corrections to improve back pain but it should not be the primary approach to back pain Tx.

Not enough research. Finally, with the multiple approaches that already exist with treating back pain, why not use

strengthening the vestibular system as another “tool in your tool belt” to. Most people with back pain respond differently to different approaches so this may be appropriate for some.

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