Relevant Clinical Background
A literature search of the United States National Library of Medicine using PubMed (www.pubmed.gov) with the words “Arnold Chiari Malformation” locates 2,995 citations (August 14, 1015).
Chiropractic clinical practice involves the application of mechanical forces to a patient’s spinal column. Should the patient’s spinal column (spinal canal) have a space occupying entity, spinal manipulation may have to be delivered more cautiously.
Typical spinal canal space occupying entities include intervertebral disc herniations, tumors, and spinal cord syrinx (a fluid filled cavity within the spinal corn, also known as syringomyelia). These lesions often present with certain symptoms and signs, and their existence is confirmed with diagnostic imaging, usually an MRI. Interestingly, the presence of these entities can also be completely asymptomatic and are found only coincidently. As an example, in 1994, The New England Journal of Medicine published a study where 98 asymptomatic subjects received MRIs of their lumbar spines. Only 36% had normal intervertebral discs at all levels, and 27% had asymptomatic disc protrusions (1).
Another important space occupying entity that may or may not present with symptomology, is the Arnold-Chiari Malformation.
What is Arnold-Chiari Malformation?
At the basic level, Arnold-Chiari Malformation occurs when parts of the brain and/or brainstem slip below the foramen magnum and are found to be in the cervical spinal canal. This compromises the available space for both the cervical spinal cord and for the parts of the brain and/or brainstem that have slipped through the foramen magnum. An important component of this mechanical space occupying compromise is an impairment of the flow of cerebral spinal fluid.
A frequent and important accompaniment of the Arnold-Chiari Malformation is that of a spinal cord syringomyelia. A syringomyelia, as noted above, is a condition in which a fluid filled cavity is present in the spinal cord and/or medulla. It creates pressure from the inside of the spinal cord, outwards:
Syringomyelia
Austrian pathologists Hans Chiari first described the Arnold-Chiari Malformation in 1891, prior to the first x-rays (Roentgen, 1895). German pathologist Julius Arnold’s name was added in 1907. Dr. Chiari described his findings based upon postmortem assessment in infants with varying degrees of congenital hindbrain deformities. Based upon Dr. Chiari’s findings, three Arnold-Chiari Malformation classifications were developed (today there are four):
Type I
There is a downward displacement of the cerebellar tonsils through the foramen magnum and into the cervical spinal canal; yet, the fourth ventricle remains in a relatively normal position.
Type II
There is a downward displacement of the cerebellar tonsils and cerebellar vermis into the cervical spinal canal; the brain stem is displaced caudally; there is an elongation of the fourth ventricle.
Type III
There is a downward displacement of both the cerebellum and medulla into the cervical spinal canal and the development of a cervical meningocele.
Arnold-Chiari Type-I Malformation Lateral View
The degree of tonsillar herniation is measured on the sagittal MRI
A = Basion, anterior foramen magnum
B = Opisthion, posterior foramen magnum
C = tonsillar tip
Line AB represents the foramen magnum
Degree of tonsillar herniation is length of perpendicular from AB to C
Arnold-Chiari Malformation is considered to be developmental or congenital. It is often associated with scoliosis, Klippel-Feil Syndrome, hydrocephalus, and syringomyelia. Adults with Arnold-Chiari Malformation Type-I may be completely asymptomatic, or they may have many dramatic symptoms. It is often asymptomatic and does not present until adulthood. Consequently, Arnold-Chiari Malformation Type-I is often found as an incidental finding on MRIs taken for other reasons. In contrast, Arnold-Chiari Malformation Type-II and Type-III are almost always found in infancy because of significant neurological findings and the presence of meningocele.
What are the Typical Symptoms of a Patient with Arnold-Chiari Malformation?
The typical symptoms attributed to the Arnold-Chiari Malformation are:
Often, the Valsalva test, or Valsalva types of activities (coughing, sneezing, straining, etc.) aggravate these symptoms.
How is Arnold-Chiari Malformation Diagnosed?
The gold standard for a suspected Arnold-Chiari Malformation is an MRI. Standard MRIs are taken with the patient recumbent. However, as detailed below, there is evidence that in the chronic whiplash trauma patient, upright MRI is significantly superior to recumbent MRI documenting the existence of the lesion (4).
Also, syrinx/syringomyelia assessment is mandatory. The entire spinal cord (especially the brain stem, cervical cord, and thoracic cord) should be assessed with T1-weighted sagittal MRI images (3).
Can Chiropractic Spinal Adjusting (Manipulation) be Safely Used to Treat the Symptoms of Arnold Chiari Malformation?
There is evidence that chiropractic care does not benefit all patients with Arnold-Chiari Type-I Malformation. In 1994, chiropractor Ross McArthur presented two cases of Arnold-Chiari Type-I Malformation in which conservative chiropractic management did not result in improvement in the patient’s clinical presentation and symptomology (3).
The first case, a 43-year old female had been under chiropractic care for 10 years, including cervical spine adjusting/manipulation. She had been treated for back pain, neck pain and occipital pain, and she always responded well to spinal adjusting.
Following a fall with head trauma, her symptoms included dizziness, photophobia, diminished smell and taste, increased suboccipital pain, and the Valsalva maneuver increased suboccipital symptoms. X-rays of the cervical spine were normal. Chiropractic care failed to improve symptoms. An MRI was exposed and revealed herniation of the cerebellar tonsils through the foramen magnum and caudal displacement of portions of the cerebellar hemispheres. A diagnosis of Arnold-Chiari Malformation Type-I was made.
The patient was treated surgically with a posterior fossa craniectomy and a complete laminectomy of the posterior arch of the atlas. The dura was opened and microdissection was used to remove tonsillar adhesions. The presence of these tonsillar adhesions suggested that her Arnold-Chiari Malformation was a long-standing problem. The patient made a full recovery and remained under chiropractic care.
In this case, chiropractic adjustment/manipulation of her cervical spine did not worsen the patient’s symptoms; they did however fail to result in meaningful improvement.
In the second case, a 50-year old female presented with spontaneous worsening symptoms in her left arm-forearm-hand, left facial paresthesias, left TMJ symptoms, and left thigh weakness. Examination showed hypertonicity of the anterior scalene and sternocleidomastoid muscles. Cervical spine X-rays were normal.
Eight chiropractic adjustments of the cervical and thoracic spines over a period of 4 weeks did not improve symptoms, and therefore an MRI was exposed. The MRI showed a typical Arnold-Chiari Malformation with syringomyelia.
Once again, chiropractic spinal adjusting/manipulation of the cervical spine did not result in meaningful improvement of the patient’s symptoms, but it did not worsen or aggravate her symptoms or clinical presentation.
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In 1993, Donald Murphy, DC, and colleagues presented two cases where chiropractic high-velocity, low-amplitude adjustments were delivered to patients that had proven Arnold-Chiari Malformation Type I (4). Although the authors do not believe that the patient’s signs and symptoms were related to the Arnold-Chiari Malformation, the presenting symptoms may suggest otherwise. In any case, both patients with known Arnold-Chiari Malformation Type I received typical chiropractic adjustments of the upper cervical spine.
The first case was a 37-year old male who was asymptomatic until being involved in a rear-end followed by head-on motor vehicle collision. Presenting symptoms include headache, neck pain, photophobia, blurred vision, and right shoulder/scapular pain. Cranial nerve and cerebellar examination was unremarkable. Cervical compression, Soto-Hall, and Valsalva tests all produced local cervical pain. Cervical extension and rotation (vertebral artery tests) were negative for dizziness, nausea, nystagmus, numbness, or paresthesia.
After 20 chiropractic adjustments over a period of 6 weeks, the patient was 50% improved; yet, an MRI at that time showed an Arnold-Chiari Malformation Type I. The patient remained under chiropractic care, receiving an additional 14 adjustments over the next 6 weeks, at which time signs and symptoms were essentially resolved. The authors state:
“The patient was treated a total of 34 times and at no time during the treatment program did he note any adverse reactions to high-velocity, low-amplitude adjustments.”
The second case was a 36-year old female with a 4-year history of chronic severe vertigo and right arm pain. She had already undergone a cervical MRI showing an Arnold-Chiari Malformation Type I. She subsequently presented for chiropractic care.
The patient had an ataxic gait, could not tandem walk or stand in Romberg’s position, and had nystagmus on all eye movements. Initial chiropractic treatment consisted of 20 visits of low-velocity, low-amplitude mobilization of the upper cervical spine. This was followed by 5 visits of high-velocity, low-amplitude adjustments of the upper cervical spine. These 25 chiropractic visits resulted in improvement but not resolution of her signs and symptoms. The authors state:
“At no time did she note any lasting adverse effects, even when high-velocity, low-amplitude adjustments were applied to the upper cervical spine.”
Asymptomatic Arnold-Chiari Malformation Type I is “not necessarily a contraindication to skilled adjustments to the cervical spine, and that viewing it as such would mean possibly denying the patient a form of treatment that could be helpful in the management of a health problem that may be unrelated to the malformation.”
The authors also make some cautionary comments:
“In a patient with a known Arnold-Chiari Malformation Type I, certain precautions may be taken to minimize any irritation to the cerebellar tonsils that have herniated through the foramen magnum.”
Avoid extension of the upper cervical spine during adjustment.
“Excessively vigorous adjusting to the upper cervical spine should be avoided, since this can potentially irritate neural structures in an already crowded canal.”
“Neither Occiput-C1 nor C1-C2 were adjusted in these patients, but there does not appear to be any reason why this would create any greater likelihood of complication.”
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In 2014, chiropractors Adam Sergent and Gregory Cofano published a study in the Journal of Chiropractic Medicine titled (5):
Chiropractic Care for Headaches and Dizziness of a 34-Year-Old Woman Previously Diagnosed With Arnold-Chiari Malformation Type-I
This 34-year-old female had a chronic history of headaches, dizziness, nausea, photophobia, and temporary loss of vision aggravated by postural positions while bending forward. These symptoms were often incapacitating. An MRI showed an Arnold-Chiari Malformation Type I, with cerebellar tonsils descending 5 mm into the cervical spinal canal. Neurosurgery was recommended.
Three years after initial diagnosis, the patient sought chiropractic and expressed her desire to avoid surgery. She was treated for 1 month with 9 visits, using high-velocity, low-amplitude adjustments of the cervical spine of prone diversified manipulation to C4/C5. She reported reduction of her headaches after this treatment.
Five years later, the patient suffered a symptomatic exacerbation. She was again treated using cervical chiropractic manipulation using prone diversified technique to C4/C5. The dizziness and headache were resolved after 3 visits. At her 3-month follow-up, she continued to be symptom-free. The authors concluded:
“A patient with headaches and dizziness and a previous diagnosis of Arnold-Chiari Malformation Type I responded positively to chiropractic care.