Treating Vertebrobasilar insufficiency, vertebrobasilar artery insufficiency, rotational vertebral artery occlusion syndrome, or Bow Hunter Syndrome
Ross Hauser, MD
Vertebrobasilar insufficiency – Bow Hunter Syndrome – Cervical neck instability. Every time I turn my head I get dizzy. Sometimes I almost pass out.
The complexity and challenges of cervical neck instability treatment are fully displayed in the controversies and confusions surrounding the diagnosis of vertebrobasilar insufficiency, also called vertebrobasilar artery insufficiency, rotational vertebral artery occlusion syndrome, or Bow Hunter Syndrome. The fact that this one diagnosis or description of symptoms is known by at least four diagnostic names should be evidence enough that patients and their doctors are sometimes not sure what they are dealing with.
As a patient diagnosed with one of these diagnostic tags, you probably know firsthand that your journey of treatment has taken many turns. Some right, some not so right, but because you are reading this article, your journey of healing is probably far from complete.
Having cervical instability can be extremely dangerous, as vertebrobasilar insufficiency (VBI) demonstrates. Impingement or compression of the vertebral arteries can cause many symptoms and conditions. The vertebral arteries supply the posterior two-fifths (40%) of the cerebrum and hindbrain, which includes the cerebellum and the lower part of the brain stem including the pons and medulla oblongata.
Proper blood flow in the vertebral arteries is crucial because these arteries travel up to form the basilar artery at the brainstem and provide circulation to the back half of the brain. When this blood supply is insufficient, vertebrobasilar insufficiency (VBI) can develop and cause symptoms such as neck pain, headaches/migraines, vertigo, dizziness, cardiovascular-like problems, drop attacks, difficulty swallowing, and/or speaking, and auditory and visual disturbances.
Vertebrobasilar insufficiency usually occurs in the presence of atherosclerosis or cervical spondylosis, but symptoms can also arise when there is intermittent vertebral artery occlusion induced by extreme rotation or extension of the head. This mechanical compression of the vertebral arteries can occur along with other anomalies, including cervical osteophytes, fibrous bands, and osseous prominences.
How rare is bow hunter syndrome? Is it really that rare?
While bow hunter syndrome (BHS, or dynamic vertebral artery compromise with “normal” neck rotation) is quoted in the medical literature as being rare, it may just be rare because physicians do not suspect it.
Discussion points of this article:
- Vertebrobasilar insufficiency – Bow Hunter Syndrome – Cervical neck instability. Every time I turn my head I get dizzy. Sometimes I almost pass out.
- A symptom of Vertebrobasilar insufficiency / Bow Hunter’s syndrome: Every time I turn my head I get dizzy. Sometimes I almost pass out.
- Symptoms of Vertebrobasilar insufficiency: Dizziness, balance problems, and blood pressure swings can be from upper cervical instability,.
- Every time the patient turned his head, he was a stroke risk. No one knew why.
- The simple treatment of Vertebrobasilar insufficiency – a neck collar.
- I was told to go home and not turn my head to prevent Vertebrobasilar insufficiency and vertebral artery compression.
- “Nowadays, various kinds of vertigo induced by neck movement are known.”
- Abnormal bony structures or bone spur development in Vertebrobasilar insufficiency.
- The 19-year-old Vertebrobasilar insufficiency patient. Everything was normal, except he passes out.
- “Bow hunter’s syndrome: a sinister cause of vertigo and syncope not to be missed” Ligament weakness observed.
- A 12-year-old girl has a stroke and during cervical fusion surgery, abnormal ligament laxity was observed.
- Something pressing on your vertebral arteries – Rotational Vertebral Artery Occlusion.
- Decompression surgery for Vertebrobasilar insufficiency.
- How does cervical instability cause Vertebrobasilar insufficiency – Bow Hunter Syndrome.
- Research and treatments for Vertebrobasilar insufficiency.
- There is very little in the medical literature to describe non-surgical conservative care treatments for Vertebrobasilar insufficiency or Bow Hunter Syndrome.
- When fusion is the “best” only answer for Vertebrobasilar insufficiency.
- Non-surgical treatment – Cervical Spine Stability and Restoring Lordosis -Making a case for regeneration and repair of the spinal ligaments.
- Atlantoaxial instability: C1 and C2 hypermobility cause Vertebrobasilar insufficiency.
- The concept of Vertebrobasilar insufficiency being caused by ligament damage is not so simple for doctors to understand. Patients suffer from big problems caused by little damage to the ligaments and the cause goes unnoticed.
- Research on cervical instability and Prolotherapy.
- New Research: Correct the problems of loss of lordosis: immediately increase cerebral blood flow.
A symptom of Vertebrobasilar insufficiency / Bow Hunter’s syndrome: Every time I turn my head I get dizzy. Sometimes I almost pass out.
When a patient comes to our center, we sit down with them and start discussing their symptoms, treatments, and their medical history up until this moment in our examination room. Let’s see if this sounds familiar to you. These anomalies were seen in about half of the cases of vertebral artery injury after cervical manipulation, as reported in a recent review.
Another reason to believe that vertebrobasilar insufficiency is from upper cervical instability is that it is common after whiplash injury and severe enough to give symptoms. Several other researchers have noted that excessive cervical instability, especially in the upper cervical spine, can cause obstruction of the vertebral artery during neck rotation, thus compromising blood flow and triggering symptoms. When symptoms are caused by mechanical compression of the vertebral artery by head rotation, it is called Bow Hunter’s syndrome (BHS). Often associated with the symptoms of dizziness, lightheadedness, vertigo, blurred vision, or even a drop attack (where the person drops to the floor because of lack of circulation in the brain) when the person rotates their neck, it can also produce nystagmus and ataxia as blood supply is cut off to the posterior part of the brain. Please see Ross Hauser, MD Reviews Cervical Spine Instability and Potential Effects on Brain Physiology.
- Many patients will tell us that they finally sought medical help because after a long period of symptoms, including sometimes or every time he/she turned his/her head they would get dizzy, lightheaded, and sometimes have to grab onto something because they felt like they were going to faint.
Fuzzy, blurry vision, ringing in the ears, and trouble with postural balance
- During these episodes, the patient would describe the above symptoms and more symptomology and describe the fuzzy, blurry vision, ringing in the ears, trouble with postural balance, and even walking. In more advanced situations and certainly more frightening to this patient is the forementioned “drop attack.” The patient would suddenly and for seemingly no reason at all, fall to the ground and then get up as if nothing had happened a few seconds later. Of course to this patient “as if nothing happened,” is not what is going through their mind. The great concern is.
When they went to their primary care physician, the patient tells us, the doctor started to suspect that they, the patient, were having some sort of blockage of blood to the brain.
- In the ruling out process, the physician started to look at atherosclerosis or the hardening of the arteries. This problem would be suspected in patients who were older, had diabetes, high blood pressure or hypertension, smoked, were obese, or led a very poor lifestyle devoid of activity or exercise. Most likely if you were in this risk group you would have received a referral to a vascular surgeon so they could take a look. However, this group of patients can suffer both atherosclerosis and vertebrobasilar insufficiency. In this group of patients, it would not take much by way of neck rotation compression to cut off blood flow to the brain in arteries that are internally clogged. Here surgeons may see more of an urgency to recommend decompression surgery.
But what if you did not have high blood pressure, or diabetes, and were not overweight? Then the diagnosis becomes even more challenging.
Let’s stop here to explain some points. You may have already performed your own research as we find that people who suffer from symptoms like those above have done extensive reading on the internet. We will do a short summary and a video presentation with Ross Hauser, MD.
Symptoms of Vertebrobasilar insufficiency: Dizziness, balance problems, and blood pressure swings can be from upper cervical instability
A June 2021 case history was presented in the journal Operative Neurosurgery. (1) It was about a successful bone spur removal surgery in a man who had compression of his vertebral artery. Sometimes the compression by bone spur is significant and has to be handled with surgery. What I want to point out is that the man was diagnosed with Rotational vertebral artery occlusion syndrome, the result of a bone spur, the likely result of upper cervical instability. Let’s have the neurosurgeons of this case history describe the situation that this man and many suffer from.
“Rotational vertebral artery occlusion syndrome, also known as bow hunter’s syndrome, is an uncommon variant of vertebrobasilar insufficiency typically occurring with head rotation. The most common presenting symptom is dizziness (76.8%), followed by visual abnormalities and syncope (50.4% and 40.4%, respectively). Osteophytic (bone spur) compression due to spinal spondylosis has been shown to be the most common etiology (46.2%), with other factors, such as a fibrous band, muscular compression, or spinal instability, being documented.”
What I also want to point out is that 46.2% of the time it is a bone spur. So more than half the time it is something else causing the patient’s problems. Included in that half of something else is spinal instability.
Summary learning points of this video
- There are a lot of people who have unexplained dizziness, balance problems, blood pressure swings, arrhythmia, palpitations, OR their heart rate can go really low.
- They go to a cardiologist or several cardiologists and other doctors and no one seems to know the cause of their heart problems.
- We find that in a lot of these cases, the person is suffering from cervical instability especially upper cervical instability.
- The sensory nerves that tell the brain what’s going on, moment to moment, in regard to heart rate and blood pressure are carried by the vagus nerve and the glossopharyngeal nerve. If the messages that these sensory nerves need to deliver to the brain are blocked or impaired, the heart symptoms described can develop.
- For more information on this subject, see our article Can cervical spine instability cause heart palpitations and blood pressure problems?
Every time the patient turned his head, he was a stroke risk. No one knew why. “For patients with posterior circulation infarction of unknown origin, a careful evaluation of vertebral arteries with physicians paying special attention to the atlantoaxial joint level is therefore recommended.”
When symptoms are caused by mechanical compression of the vertebral artery by head rotation, it is called Bow Hunter’s syndrome (BHS). A pathognomonic finding of Bow Hunter’s syndrome is the improvement of symptoms when the patient is in a neutral position, as the circulation to the posterior part of the brain is restored. If a stroke occurs because of occlusion of the vertebral artery with head movement it is called Bow Hunter’s stroke. Diagnosis is made by angiogram, MR angiogram, or CT angiogram with the head in neutral and then another angiogram with the head in rotation on the side of occlusion.
Doctors at the Department of Neurology, Kitano Hospital, The Tazuke Kofukai Medical Research Institute, Japan reported on a case history of a 61-year-old man who had recurrent strokes. This man had an “invisible” cervical neck instability problem that compresses his arteries. Here is the summary of this case published in the journal Internal Medicine. (2)
There is a compression problem between C1-C2
- Vertebral arteries are vulnerable to mechanical stress between the atlas and axis, and subsequent vertebral artery dissection can cause posterior circulation infarction (blocked, compressed blood flow in the back of the head).
- In this case, the patient had bilateral vertebral artery aneurysms that caused the recurrent stroke.
In June 2021 Chilean doctors writing in the European Spine Journal (17) presented a case of a patient with dynamic left vertebral artery occlusion associated with idiopathic rotatory C1-C2 subluxation. “A dynamic Angio-CT showed rotatory C1-C2 subluxation with significant flow reduction at the left vertebral artery at the exit of the C2 transverse foramen until the V3 segment (where the artery begins its loop at C2 and turns to move up to the transverse foramen) when the head rotated towards the right. Due to clinical and radiological worsening in the following months, posterior C1-C2 arthrodesis (cervical fusion) was performed, with the disappearance of the symptoms. There are 193 cases reported with dynamic vertebral artery occlusion, but in only two, the etiology was primary rotational atlantoaxial instability. The most prevalent etiology was degenerative.”
In this paper, the researchers suggested in their findings, that about 1 in 100 patients can have dynamic left vertebral artery occlusion traced to C1-C2 subluxation.
His doctors did not see an obvious cause of this blood flow blockage but suspected it was compression in the C1-C2 area. The strokes stopped after the patient was fitted for neck collar fixation
- The localization of the aneurysms and dynamic angiography with neck movement suggested that the strokes were related to chronic mechanical injury of the vertebral arteries, though no skeletal abnormality was detected. The recurrences stopped and both aneurysms shrank after neck collar fixation and after the combination use of antithrombotics (blood thinners). For patients with posterior circulation infarction of unknown origin, a careful evaluation of vertebral arteries with physicians paying special attention to the atlantoaxial joint level is therefore recommended.
When the neck was stabilized with a neck collar, aneurysms shrank, and recurrent strokes stopped
Some key comments:
- There was nothing obvious in the patient’s neck that suggested an anatomical neck injury. The patient’s cervical neck instability was not seen.
- The problem was detected with imagery related to neck movement. When he moved his neck, dynamic angiography picked up the compression of the arteries. Please see our discussion below on DMX. Digital Motion X-Ray is an x-ray movie we utilize to observe these types of “unseen” compressions during movement.
- When the neck was stabilized with a neck collar, aneurysms shrank, and recurrent strokes stopped.
The simple treatment of Vertebrobasilar insufficiency – a neck collar
We have an extensive article on Cervical collars – why do they help some people and not others? In that article, we discuss the use of a cervical collar or cervical traction in an attempt to alleviate the patient’s symptoms by stretching the spinal vertebrae to relieve pressure and pain on the nerves that transverse the cervical vertebrae. For many patients, this will provide relief of symptoms. For some patients, the cervical collar may cause more problems than it was designed to help.
What are we seeing in this image?
The image below is a demonstration of three parts of how a cervical neck brace may help cervical spine instability. The patient is having a Digital Motion X-ray (DMX) so we can watch the motion of her neck.
- In the first part, the patient puts her chin on her chest, she is not wearing a collar. The DMX reveals extreme hypermobility during cervical flexion
- In the second part, the patient tries to put her chin on her chest, while she is wearing a neck collar. The DMX records an about 50% reduction in hypermobility of the cervical spine segment.
- In the third part, the patient is given a more supportive collar. The cervical instability is nearly eliminated during collar wear. Let’s stress at this point that the collar is not a cure, it is a symptom suppression device.
I was told to go home and not turn my head to prevent Vertebrobasilar insufficiency and vertebral artery compression.
Someone will tell us a story that goes something like this. One day, a normal day like any other day, they were getting out of bed reading to go to their physically demanding line of work. Suddenly, upon rising they suffered from a severe case of vertigo and collapsed back onto the bed, they lay on their bed almost to the point of paralysis, nearly immobilized. By the time they could summon medical help, nausea, and vomiting set in. In the emergency room CT, MRI, and MRA were taken. The attending doctors came back to them to tell them that “everything was normal.” One orthopedist specialist did comment on the severe degenerative arthritis and bone spurs at C1-C2. As an afterthought degenerative disc disease was also noted in C4-C7 or C4-C5 or C5-C6.
Everyone seemed to be scratching their heads as to what caused this “super vertigo” event. The person in this story said they had no headaches and no pain prior to the event. Nothing was adding up. A consultation with a neurologist was able to confirm vertebral artery compression. At that point, the person in the story said that they got their first “real good” medical advice. They were told to go home and not turn their head.
Next, they got advice that as someone who does physically challenging work and may own their own business does not want to hear, the orthopedist and the neurosurgeon would come up with a plan for cervical fusion surgery. They would be away from the job for months.
“Nowadays, various kinds of vertigo induced by neck movement are known.”
A November 2020 case history published in the BioMed Central Neurology (3) discusses the vision problems of Nystagmus. We have a more extensive article on this condition here: Nystagmus – Oscillopsia caused by cervical spine instability and neck pain.
“Bow Hunter’s Syndrome (BHS) is known as one of the cervical diseases which cause vertigo, but the details of its vertigo, especially nystagmus and eye movement, are still incompletely understood.
The patient, a 47-year-old female, complained of vertigo caused by head rotation.
When she turned her head leftward, leftward nystagmus appeared, and this was followed by the dullness of the right arm.
After her head was returned to the central position, downbeat nystagmus appeared (eyes drift up and then corrective action is taken to drift them back down) which changed to rightward nystagmus. She was diagnosed with BHS by her symptoms and images. Her vertigo was cured by the modification of a prescription for her past medical history: hypertension.
Conclusion: “The vertigo of Bow Hunter’s Syndrome accompanies nystagmus. In this present case, transitional nystagmus was observed, and it occurred toward the healthy side. Then the nystagmus direction was changed to the affected side via downbeat nystagmus. . . Nowadays, various kinds of vertigo induced by neck movement are known. Bow Hunter’s Syndrome is a rare disease among vertigo diseases, but we should consider it a different diagnosis for vertigo patients. A precise interview and proper examination are required to make the final diagnosis.”
In this case history, the doctors focused on hypertension. At our center we focus on the cervical spine as the focal point of the myriad of symptoms patients may suffer from. In many people, we find the cause of their symptoms to be a weakness in the cervical spine ligaments. The tough connective bands hold the cervical spine in place.
Abnormal bony structures or bone spur development in Vertebrobasilar insufficiency
As noted and as we will continuously see in the medical research, turning one’s head from side to side can imitate symptoms in the patient diagnosed with rotational vertebral artery occlusion syndrome.
A paper in the journal Interventional Neurology (4) described the role of abnormal bone structures and developing bone spurs.
“Bow hunter’s syndrome also known as rotational vertebral artery occlusion syndrome is a rare yet treatable type of symptomatic vertebrobasilar insufficiency resulting from mechanical occlusion or stenosis of the vertebral artery during head and neck rotation or extension. The symptoms of Bow hunter’s syndrome range from transient vertigo to posterior circulation stroke. The underlying pathology is dynamic stenosis or compression of the vertebral artery by abnormal bony structures with neck rotation or extension in many cases, such as osteophyte (bone spur), disc herniation (cervical spine instability), cervical spondylosis (more cervical spine instability), tendinous bands (the tendons of the neck are weak and reducing the power of the cervical spine muscles to power movement) or tumors.”
The 19-year-old Vertebrobasilar insufficiency patient. Everything was normal, except he passes out.
Many people come to our center and they ask a question that goes something like this: “how come no one else saw cervical instability as a problem?” In fact, many times cervical instability is recognized as a problem, but as we began this article, when a symptom or a condition can go by at least four different diagnostic tags, there will be confusion.
It is also important for us to point out that we are not the only center seeing this. We are however a center that treats these problems non-surgically.
Let’s look at a case history presented in the journal Radiology Case Reports, (5) published in November 2020. The case is presented with our explanatory notes: In this case, we will go to the conclusion first: “Bow Hunter’s syndrome should be differentiated from vertebral artery type cervical spondylosis and ischemic stroke. They have similar symptoms, such as dizziness, and disturbance of consciousness, which are easily confused clinically.” Now the case:
“On March 20th, 2019, a 19-year-old male student, after cleaning the classroom experienced dizziness around half an hour after looking up, accompanied by rotation of visual objects, binocular blackness, and disturbance of consciousness but with, no nausea, vomiting, or tinnitus.
In the local hospital, no obvious abnormality was found in the MRI of the head, cervical spine, and lumbar spine. At this time, the patient felt dizzy when walking and normal when sitting or lying down. The patient confirmed no history of craniocerebral and cervical trauma.
. . . the patient underwent head and neck dynamically computed tomography angiography (CTA) examination. Head and neck dynamic computed tomography angiography showed, that when the patient was located in a neutral position, the bilateral vertebral artery (was seen) well, and the right vertebral artery was thinner than the left. The patient was told to turn 90° to the left, where the virtual reality and multiplanar reconstruction (high image definition) of the vertebral artery showed local interruption of the upper edge blood flow of the C2 level of the right vertebral artery, and the contralateral vertebral artery developed well.
The patient was told to turn the head 90° to the right, after which the vertebral artery and curved surface reconstruction MPR showed local interruption of the left vertebral artery C2 level superior edge blood flow, and the contralateral vertebral artery developed well. The patients completed other laboratory tests and received symptomatic treatment such as improving circulation and brain protection.”
In this case, dynamically computed tomography angiography was used to discover rotational problems, and therapies and medications were utilized to help the patient’s symptoms. Below, in treating the same type of patient we also use various testing techniques but as I will explain our treatments surround treating the cervical instability that allows the bones of the neck to compress veins and arteries.
“Bow hunter’s syndrome: a sinister cause of vertigo and syncope not to be missed” Ligament weakness observed
Above is the title of an April 2020 (6) medical paper. It comes from the Department of Radiology, Princess Margaret Hospital, Hong Kong. Listen to what these researchers said:
The pathogenesis of Bow hunter’s syndrome is related to the tortuous anatomical course of the vertebral artery along the cervical spine, which renders the artery susceptible to extrinsic compression, and repetitive shear stress resulting in hemodynamic (loss of blood flow) events in at-risk patients during head and neck rotation. Osteophytes (bone spurs), disc herniation, ligamentous (ligament weakness), or neck muscle hypertrophy are risk factors for Bow hunter’s syndrome.
Though rare, Bow hunter’s syndrome is a not-to-be-missed cause of vertigo, owing to its specific relationship with head and neck rotation and its potential risk of posterior circulation ischaemic stroke.
Bow hunter’s syndrome is more common among males and those aged between 50 and 70 years old. Common clinical manifestations include vertigo and syncope (fainting). Other symptoms include nystagmus (vision problems), emesis (vomiting), Horner’s syndrome (pupil dilation, a drooping eyelid), and rarely motor and sensory deficits.
Imaging (diagnosis) is crucial in establishing the diagnosis of Bow hunter’s syndrome, delineating the cause and site of extrinsic compression, and evaluating complications such as infarction.
A 12-year-old girl has a stroke and during cervical fusion surgery, abnormal ligament laxity was observed.
In a June 2020 study in the Journal of Child Neurology (7) researchers at Division of Child Neurology, Department of Neurology, Indiana University School of Medicine reviewed the medical literature and noted: “Bow hunter’s syndrome, or occlusion of the vertebral artery with head rotation leading to ischemia and sometimes stroke, is rarely described in children.”
The authors reviewed the literature and presented a new case.
Highlights of this research:
- Twelve articles (medical studies) were found describing 25 patients; there were 26 patients when combined with our case.
- Ages ranged from 1 to 18 years. Most (88.5%, 23/26) were male.
- Medical treatments included aspirin, clopidogrel, abciximab, enoxaparin, warfarin, and cervical collar.
- Stenting was tried in 2 cases but did not work long-term.
- Surgical treatments included decompression, cervical fusion, or a combination. We present a new case of a 12-year-old girl with recurrent stroke who had bilateral vascular compression-only visible on provocative angiographic imaging with head turn. She was referred for cervical fusion, and abnormal ligamentous laxity was noted intraoperatively.
For some children, surgery may be necessary. For some children, we believe we can address the problem of abnormal ligament laxity with non-surgical treatments as we describe below.
Something pressing on your vertebral arteries – Rotational Vertebral Artery Occlusion
This article will focus on one aspect of Vertebrobasilar insufficiency, which occurs with head rotation (Rotational Vertebral Artery Occlusion) brought on by cervical neck instability. Vertebrobasilar insufficiency can be brought on by many things as outlined above dominated by a concern of atherosclerosis. This article is for patients who have been checked for atherosclerosis and are still looking for answers. The answer we will present is the repair of cervical neck instability by strengthening the cervical ligaments and tendon attachments and restoring the natural curve of the neck.
Decompression surgery for Vertebrobasilar insufficiency
Your journey to correcting your symptoms has likely introduced you to a new awareness of medical terms and medical specialties. You may have had an otolaryngological examination from an Ear, Nose, and Throat specialist. You may have had discussions with the Otolaryngologist or surgeon about possible solutions. You start hearing the word “Decompression,” a lot. Decompression means surgery that will remove part of cervical vertebrae to prevent compression, or something pressing on the vertebral artery at the “point of impact.”
This is what you do know or you should know.
The vertebral arteries supply 20% of the blood flow to the brain by way of the Basilar artery. Vertebrobasilar insufficiency occurs when blood flow is disrupted. Once severe atherosclerosis is ruled out as an immediate stroke risk, doctors should explore underlying upper cervical instability. That of course is our opinion. We are going to get to the research below.
The vertebral arteries travel up through the cervical vertebrae (one on each side) through foramina (or “holes”) in a bony prominence called the transverse process of the vertebrae.
Bow hunter’s syndrome originates in the posterior inferior cerebellar artery
In October 2021, doctors at the Department of Neurosurgery, Kawasaki Medical School in Japan reported on a case of Bow hunter’s syndrome extracranially originating in the posterior inferior cerebellar artery. The case appears in the journal Frontiers in Neurology (16). Why this case was significant enough to publish was that Bow hunter’s syndrome had previously not been known to occur due to an extracranially originated posterior inferior cerebellar artery.
Note: The posterior inferior cerebellar artery (PICA) is the vertebral artery’s most extensive branch and one of the three main arteries that supply blood to the cerebellum. When blocked or compressed, the posterior inferior cerebellar artery can cause the lateral medullary syndrome, or Wallenberg syndrome, an acute ischemic infarct (tissue death from blot clot and blood flow blockage) of the lateral medulla oblongata.
In this case, a 71-year-old man appeared before the doctors with reproducible dizziness on leftward head rotation, indicative of Bow hunter’s syndrome. During the patient’s head rotation that induced dizziness, the right posterior inferior cerebellar artery was occluded, and vertebral artery stenosis was revealed. Occlusion of the posterior inferior cerebellar artery was considered to be the primary cause of the dizziness. The patient underwent surgery to decompress the right posterior inferior cerebellar artery and vertebral artery via a posterior cervical approach. Following surgery, the patient’s dizziness disappeared, and the stenotic change at the right vertebral artery and posterior inferior cerebellar artery improved. The posterior inferior cerebellar artery could be a causative artery for BHS when it originates extracranially at the atlas-axis level, and posterior decompression is an effective way to treat it.
What are we seeing in the next image?
In this illustration, the vertebral artery is clearly seen weaving its way through C1-C2. If the C1-C2 are moving and hypermobile, they could press on and compress the vertebral artery. This could cause the sensation of lightheadedness and feeling faint. This is seen in the x-ray below.
What are we seeing in this image?
In this x-ray, when the patient looks down, a 6 mm space opens between the C1-c2. When the patient looks up, 0 mm, no space. Everything between those two surfaces is compressed. If the patient only had a static image of their cervical spine in flexion or neutral pose, “nothing would be wrong.” What is wrong is only discovered when the patient points their chin upwards.
When it gets to the upper cervical spine at C1, the vertebral arteries follow more of a serpentine path up to the brain. It is here that these arteries are at risk of “kinking” and therefore shutting off blood flow to the brain.
How does cervical instability cause this?
With normal neck rotation (i.e. looking over your shoulder), C1 rotates over the dens (the “pivot” or Odontoid Process) of C2 that making head rotation possible. This simple rotation can partially compress the vertebral arteries (more specifically, the artery on the same side you are looking over) with normal movement. In someone with an unstable cervical spine who suffers from neck hypermobility, this can occur on a more regular basis and cause many of the symptoms we described above. One of the most common symptoms of vertebrobasilar insufficiency is drop attacks, which as we mentioned above, can cause the person to suddenly fall to the ground without warning (but remains conscious). It has been proposed that drop attacks may occur from transient loss of blood flow to the brain stem (from the vertebral arteries).
As we also mentioned above, other symptoms include dizziness, fainting, blurred vision, visual and auditory disturbances, flushing, sweating, tearing of the eyes, runny nose, vertigo, numbness and tingling, and difficulty swallowing or talking. It should be noted that instability along any of the entire cervical spine can cause kinking of the vertebral arteries as they travel through each vertebra, but it is often related to the upper cervical spine.
In our clinic’s research published in The Open Orthopaedics Journal (8), we wrote that the capsular ligaments are the main stabilizing structures of the facet joints in the cervical spine and have been implicated as a major source of chronic neck pain. Such pain often reflects a state of instability in the cervical spine and is a symptom common to a number of conditions such as disc herniation, cervical spondylosis, whiplash injury, whiplash-associated disorder, post-concussion syndrome, vertebrobasilar insufficiency, and cervicocranial syndrome. When the capsular ligaments are injured, they become elongated and exhibit laxity, which causes excessive movement of the cervical vertebrae. In the upper cervical spine (C0-C2), this can cause symptoms such as nerve irritation and vertebrobasilar insufficiency with associated vertigo, tinnitus, dizziness, facial pain, arm pain, and migraine headaches.
What are we seeing in this image?
The cervical spine is intertwined with nerves and blood vessels. Cervical spine instability can compress or pinch the nerves and arteries causing a myriad of symptoms depending on how the patient moves his/her head. Cervical spine instability can cause restriction and compression of vital arteries and nerves that supply blood and sensation to the brain, face, and neck.
Research and treatments for Vertebrobasilar insufficiency
The medical literature treats Vertebrobasilar insufficiency and Hunter Bow Syndrome as “somewhat” or “extremely rare” disorders. Yet here you are with drop attacks, dizzy spells, and related symptoms. There is very little research on treatment options other than case histories presented to illustrate the difficulty and confusion surrounding these cases. We are going to present the evidence that vertebrae instability through compromise or weakening of the cervical ligaments and tendon attachment between muscle and vertebrae are in play.
Decompression and Cervical Fusion surgery
By this time of your health journey, you may have been recommended for a cervical fusion surgery or a cervical decompression to cut away that piece of the vertebrae causing the pinching of your vertebral artery compression. When discussing the pros and cons of surgery, it is always best to bring in surgical research presented by surgeons.
In the medical journal Stroke, (9) surgeons from the Department of Neurology, Pusan National University Hospital in South Korea presented these findings:
- “On the basis of their safety, effectiveness, and good long-term outcome, surgical treatments, including cervical decompression or cervical spine fusion, have been recommended as the first-line treatment option for Rotational Vertebral Artery Occlusion.
- Although cervical spine fusion provides complete relief of the symptoms and no re-occlusion of the Vertebral Artery, most patients experience a significantly restricted range of head motion postoperatively, which restrains daily activities.
- However, cervical decompression does not limit physiological neck movements, but it has the problem of a high re-occlusion rate because of post-operative adhesion between the vertebral artery and the adjacent soft tissues.
- Another alternative is endovascular stent placement in the unaffected Vertebral Artery to increase the blood flow during head rotation. However, its efficacy and long-term outcome remain uncertain, and it cannot be performed in all patients.”
The surgeons’ success with conservative care:
- “Our study showed a favorable long-term outcome of conservative treatments in Rotational Vertebral Artery Occlusion. None of our patients with conservative treatments developed posterior circulation stroke, and 4 of them showed resolution of the symptoms during the follow-up, possibly because of spontaneous resolution of the extrinsic compression or central adaptation. Our results suggest that conservative treatments are safe and might be considered as a first-line treatment in Rotational Vertebral Artery Occlusion.”
Let’s go over this study and condense it to a few learning points
- Cervical Spinal Fusion – lessens or cures symptoms. May be necessary for some patients. There is a price to pay for the permanent ability to rotate the neck including the inability thereafter to drive a car because you cannot “look both ways.”
- Cervical decompression surgery – less successful, possible need for future surgeries
- Conservative care treatment, in this case, blood thinners and education and training on how to avoid rapid head movement seemed to be as effective as fusion surgery.
There is very little in the medical literature to describe non-surgical conservative care treatments for Vertebrobasilar insufficiency or Bow Hunter Syndrome
If you reviewed the medical literature surrounding Bow Hunter Syndrome, described as a type of Vertebrobasilar insufficiency, you will see little by way of conservative non-surgical treatment but many papers that describe the various surgical interventions that can be applied with some surgeons favoring one surgery over another. Many papers also discuss the logical progression of successive surgeries that the patient will need.
Bow Hunter Syndrome is so named because of a case presented to the scientific community in 1978 by neurosurgeon BF Sorensen (10) of a young bowhunter who following archery, suffered a vertebral artery injury from the way he held his bow.
In 2014, surgeons from the Barrow Neurological Institute gave their fellow doctors and patients an assessment of their 15 years of experience in the management of bow hunter’s syndrome. This research was published in the journal World Neurosurgery. (11)
- “There were 14 patients referred to Barrow Neurological Institute with symptoms concerning bow hunter’s syndrome, and 11 of these patients were confirmed to have dynamic vertebral artery compression on angiography.
- The location of compression was centered on
- C1-2 (50%) or C5-7 (50%).
- The compressed vertebral artery was typically the left artery (72.7%), and in 54.5% of cases, rotation of the head to the contralateral side produced symptomatic dynamic compression.
- Surgical decompression, via either an anterior (44.4%) or a posterior (55.6%) approach, was eventually performed in 9 patients. Decompression alone was performed in all cases; however, 1 patient developed cervical instability requiring an anterior cervical instrumented fusion 5 years later.
The recommendation here was that the decompression surgery could help in the short term but, as mentioned in the research above, there may be long-term complications including cervical instability, which may necessitate more surgery including the fusion that few patients truly desire.
Research all the way through January 2019 continuously discusses the short-term benefit of compression surgery vs the long-term consequences leading up to cervical fusion. In fact, a February 2019 study takes the comparison of surgeon vs surgeon. This comes from the Icahn School of Medicine at Mount Sinai in New York and was published in the journal Spine (12).
“When examining a large institutional sample and an even larger national sample, this study found that orthopedic surgeons were more likely to encounter perioperative bleeding requiring transfusion than neurological surgeons. When in-hospital complications were considered as a whole, in the national sample, orthopedic surgeons are more likely to encounter in-hospital complications than neurological surgeons when performing Posterior Cervical Decompression and Fusion.”
When fusion is the “best” only answer for Vertebrobasilar insufficiency
The challenges of cervical fusion are many and should be a last resort option. Often patients will tell us that their doctors are very confident that the surgery will go well but the patients are still apprehensive, even frightened. There are times when surgery may be needed. This is when bone spurring or bony overgrowth itself is pressing against the artery. This type of problem is indicative of someone much older in age and suffering from very advanced cervical degenerative disc disease.
A May 2022 case history present in the World journal of clinical cases (18) describes the case of a 70-year-old patient suffering from an acute onset of vertigo and gait instability which doctors attributed as being triggered by right head rotation. The man’s medical history included previous episodes of unilateral left neck and occipital pain followed by light-headedness, sweating, and blurred vision when turning his head, and these episodes were associated with severe degenerative changes in the atlanto-dens and left atlanto-axial facet joints and right rotation of the C2 cervical vertebrae.
Brain MRI revealed the presence of acute bilateral cerebellar ischaemic lesions, while static vascular imaging did not reveal any vertebral artery abnormalities. Dynamic ultrasonography and angiography were performed and confirmed the presence of a dynamic occlusion of the vertebral artery V3-V4 segment when the head was rotated to the right secondary to left C1-C2 bone spur compression. Surgical decompression led to complete resolution of paroxysmal symptoms without neurological sequelae.
Conclusion: Bow hunter’s syndrome should be considered in cases of repeated posterior circulation transient ischaemic attack or ischaemic stroke, particularly when associated with high cervical spine abnormalities.
Non-surgical treatment – Cervical Spine Stability and Restoring Lordosis -Making a case for regeneration and repair of the spinal ligaments. What are we seeing in this image?
The cervical spine has a natural curve. It acts as a spring or shock absorber for the head. When this curve is gone because of injury, Joint Hypermobility Syndrome, or degenerative cervical disc disease, not only are the arteries and nerves between the vertebrae not protected from the impact of walking or running or jumping or a bumpy car ride, but they are subjected to compression from cervical spine instability caused by cervical ligaments that have also been damaged by injury or wear and tear and no longer hold the neck in correct alignment.
In this section, we are going to talk about the realistic non-surgical options for the treatment of Vertebrobasilar insufficiency and its related symptoms.
Above we spoke briefly spoke about blood thinners and patient training to avoid certain head rotations, these are treatments that handle symptoms suppression and management. In this section, we will discuss the use of simple dextrose injections or blood platelet injections to restore stability in the cervical spine by addressing and repairing damaged support tissue in the neck.
Atlantoaxial instability: C1 and C2 hypermobility causes Vertebrobasilar insufficiency
Atlantoaxial instability is the abnormal, excessive movement of the joint between the atlas (C1) and axis (C2). This junction is a unique junction in the cervical spine as the C1 and C2 are not shaped like cervical vertebrae. They are more flattened so as to serve as a platform to hold the head up. The bundle of ligaments that support this joint is strong bands that provide strength and stability while allowing the flexibility of head movement and allow unimpeded access (prevention of herniation or “pinch”) of blood vessels that travel through them to the brain.
Fixing the ligaments is usually not the first choice among more traditional doctors in treating Vertebrobasilar insufficiency. As we have seen fusion or decompression surgery is. Cervical ligament injury should be more widely viewed as a key treatment for vertebrobasilar insufficiency.
In a 2015 paper appearing in the Journal of Prolotherapy, (13) our research team wrote that cervical ligament injury should be more widely viewed as the underlying pathophysiology (the cause of) atlantoaxial instability and the primary cause of cervical myelopathy (disease) including the problems of Vertebrobasilar insufficiency. This was a continuation of the series of published research Caring Medical is producing on the problems of cervical instability including the 2014 article Chronic Neck Pain: Making the Connection Between Capsular Ligament Laxity and Cervical Instability that we mentioned above.
The concept of Vertebrobasilar insufficiency being caused by ligament damage is not so simple for doctors to understand. Patients suffer from big problems caused by little damage to the ligaments and the cause goes unnoticed.
The problems of Vertebrobasilar insufficiency are not problems that sit in isolation. A patient that suffers from Vertebrobasilar insufficiency will likely be seen to suffer from many problems as they all relate to upper cervical neck ligament damage and cervical instability. As demonstrated below this includes cervical subluxation, (misalignment of the cervical vertabrae). One of the causes of Vertebrobasilar insufficiency is this cervical misalignment and its “pinching,” or “herniation,” not of a disc, but of the arteries themselves as we suggested above. This creates the situation of ischemia (damage to the blood vessels).
The problems of vertebrobasilar insufficiency are not problems that sit in isolation. A patient that suffers from vertebrobasilar insufficiency will likely be seen to suffer from many problems as they all relate to upper cervical neck ligament damage and cervical instability
Research on cervical instability and Prolotherapy
Caring Medical has published dozens of papers on Prolotherapy injections as a treatment for difficult-to-treat musculoskeletal disorders. We are going to refer to two of these studies as they relate to cervical instability and a myriad of related symptoms including the problem of Vertebrobasilar insufficiency.
In our study mentioned earlier in this article, we published a comprehensive review of the problems related to weakened damaged cervical neck ligaments.
This is what we wrote: “To date, there is no consensus on the diagnosis of cervical spine instability or on traditional treatments that relieve chronic neck instability issues like those mentioned above. In such cases, patients often seek out alternative treatments for pain and symptom relief. Prolotherapy is one such treatment that is intended for acute and chronic musculoskeletal injuries, including those causing chronic neck pain related to underlying joint instability and ligament laxity. While these symptom classifications should be obvious signs of a patient in distress, the cause of the problems is not so obvious. Further and unfortunately, there is often no correlation between the hypermobility or subluxation of the vertebrae, clinical signs or symptoms, or neurological signs or symptoms. Sometimes there are no symptoms at all which further broadens the already very wide spectrum of possible diagnoses for cervical instability.”
What we demonstrated in this study is that the cervical neck ligaments are the main stabilizing structures of the cervical facet joints in the cervical spine and have been implicated as a major source of chronic neck pain and in the case of Vertebrobasilar insufficiency type symptoms, cervical instability.
Prolotherapy is referred to as a regenerative injection technique (RIT) because it is based on the premise that the regenerative/reparative healing process can rebuild and repair damaged soft tissue structures. It is a simple injection treatment that addresses very complex issues.
We propose that in many cases of chronic neck pain, the cause may be underlying joint instability due to capsular ligament laxity. Currently, curative treatment options for this type of cervical instability are inconclusive and inadequate. Based on clinical studies and experience with patients who have visited our chronic pain clinic with complaints of chronic neck pain, we contend that Prolotherapy offers a potentially curative treatment option for chronic neck pain related to capsular ligament laxity and underlying cervical instability.”
Actual Prolotherapy treatment
Caring Medical has published dozens of papers on Prolotherapy injections as a treatment for difficult-to-treat musculoskeletal disorders. We are going to refer to our 2014 study where we published a comprehensive review of the problems related to weakened damaged cervical neck ligaments.
This video jumps to 1:05 where the actual treatment begins.
This patient is having C1-C2 areas treated. Ross Hauser, MD, is giving the injections.
Prolotherapy, the curve of the neck and blood flow
In February 2016 a paper appeared in the Medical Science Monitor: International Medical Journal of Experimental and Clinical Research. (14) Here medical university researchers in Turkey made these observations:
- “The vertebral arteries proceed in the transverse foramen of each cervical vertebra. Considering that the vertebral arteries travel in a close anatomical relationship to the cervical spine, we speculated that the loss of cervical lordosis may affect vertebral artery hemodynamics. (Reduced blood flow into the brain).”
- “(Our) study revealed a significant association between a loss of cervical lordosis and decreased vertebral artery hemodynamics, including diameter, flow volume, and peak systolic velocity.”
This is research with which we have seen empirical evidence in our over 27 years of regenerative medicine practice. To fix the problems related to the cervical spine, you need to restore the natural curvature of the neck. This is part of our Caring Cervical Realignment Therapy (CCRT) developed by Ross Hauser, M.D. This program was the evolutionary product of decades of treating patients with neck disorders, including cervical instability and degenerative disc disease, to provide long-term solutions to cervical neck instability-related symptoms. CCRT combines individualized protocols to objectively document spinal instability, strengthen weakened ligament tissue that connects vertebrae, re-establish normal biomechanics and encourage the restoration of lordosis.
Please see our article and video Chiropractic adjustments and cervical traction – addressing cervical lordosis. See also our article on treatments for Atlas displacement c1 forward misalignment.
New Research: Correct the problems of loss of lordosis: immediately increase cerebral blood flow
In the medical journal Brain Circulation (Jan-March 2019) (15), doctors wrote off their analysis of case study patients who had cervical lordosis. They wrote that if you restored the natural curve to the neck, you could immediately increase cerebral blood flow as pressure is removed from the cerebral artery.
Here are the learning points of this research. They present a good summary of what we discussed in this article:
- Loss of lordosis of the cervical spine is associated with decreased vertebral artery hemodynamics (blood flow).
- Based on the close anatomical relationship between the cervical spine, the vertebral arteries, and cerebral vasculature, the researchers speculated that improvement in cervical hypolordosis increases collateral (from the side) cerebral artery hemodynamics and circulation.
The challenges of Vertebrobasilar insufficiency are many. Fixing cervical neck instability is not something that can be treated simply or easily, it takes a comprehensive non-surgical program to get the patient’s instability stabilized and the symptoms abated. We believe that if you have been going from clinician to clinician, practitioner to practitioner, doctor to doctor, there is a good likelihood that you have problems of cervical neck instability coming from weakness and damage to the cervical ligaments. Our treatments of dextrose Prolotherapy and in some cases Platelet Rich Plasma Prolotherapy can be an answer.
How do I know if I’m a good candidate?
Vertebrobasilar insufficiency (VBI) is poor blood flow to the back portion of the brain or decreased circulation to the brainstem. This decreased circulation can be caused by compression of the vertebral and basilar arteries which supply blood to many vessels in in the back of the brain. This includes the basilar artery which is joined to the brainstem. The intracranial part of the vertebral arteries and their branches supply the medulla with blood. The vertebral arteries then join the basilar artery and the pons receives their blood supply from those and their branches.
The consequences of undiagnosed Vertebrobasilar insufficiency can be severe as we have discussed above. Occlusions of these arteries cause stroke and vertebrobasilar insufficiency can lead to an intermittently oxygen-starved brain (transient ischemia). Symptoms of Vertebrobasilar insufficiency include dizziness, headaches, swallowing difficulties, vomiting, blindness, double vision, dilated eyes, drooping eyelids, ataxia, weakness, and imbalance of legs. Drop attacks (sudden fall due to loss of proper limb function), mental confusion, paresthesia, and tinnitus are also reported.
More than 60% of Vertebrobasilar insufficiency patients experience dizziness. Most patients experience multiple symptoms once for minutes at a time due to transient ischemia. VBI should be suspected if positional dizziness is accompanied by neurological symptoms. Rotational occlusion of the vertebral artery may induce transitory ischemia. Sudden occlusions of the vertebral and basilar arteries can cause ischemic damage and severe clinical deficits. Instability at the craniocervical junction could cause vertebrobasilar insufficiency by causing these occlusions. Symptoms of Vertebrobasilar insufficiency were reproducible with rotational head movement; showing that rotational vertebral occlusion is an important cause.
Vertebrobasilar insufficiency usually occurs in the presence of atherosclerosis or cervical spondylosis, but symptoms can also arise when there is intermittent vertebral artery occlusion induced by extreme rotation or extension of the head. This mechanical compression of the vertebral arteries can occur along with other anomalies, including cervical osteophytes (bone spurs), fibrous bands, and osseous prominences (bone overgrowths). These anomalies are seen in many cases of vertebral artery injury after cervical manipulation, as reported in a recent review.
We hope you found this article informative and that it helped answer many of the questions you may have surrounding the challenges that you may be facing. Just like you, we want to make sure you are a good fit for our clinic prior to accepting your case. While our mission is to help as many people with chronic pain as we can, sadly, we cannot accept all cases. We have a multi-step process so our team can really get to know you and your case to ensure that it sounds like you are a good fit for the unique testing and treatments that we offer here.
If you would like to get more information specific to your challenges please email us: Get help and information from our Caring Medical staff
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This article was updated June 9, 2022