Treating Vertebrobasilar insufficiency – Bow hunter’s syndrome

Ross Hauser, MD, Caring Medical Florida, Fort Myers

Vertebrobasilar insufficiency – Bow Hunter Syndrome – Cervical neck instability. Everytime I turn my head I get dizzy. Sometimes I almost pass out.

The complexity and challenges of cervical neck instability treatment is fully displayed in the controversies and confusions surrounding the diagnosis of vertebrobasilar insufficiency, also called vertebrobasilar artery insufficiency or Bow Hunter Syndrome. As a patient diagnosed with one of these diagnostic tags, you probably know first hand 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.

When a patient comes into our clinic, 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.

Everytime I turn my head I get dizzy. Sometimes I almost pass out

  • The patient will tell us that they finally went to get help because for a long time, 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.
  • During these episodes the patient would also experience fuzzy, blurry vision, ringing in the ears and trouble with postural balance, even walking. In more advanced situations and certainly more frightening to this patient is the “drop attack,” where they 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. Great concern is.
  • When they went to their primary care physician, the patient tells us, the doctor started to suspect that they, the patient, was having some sort of blockage of blood to the brain.
  • In the ruling out process, the physician started to look at atherosclerosis, or a hardening of the arteries. This problem would be suspected in patients who were older, had diabetes, high blood pressure or hypertension, smoked, was 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 from 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 a decompression surgery.

Everytime the patient turned his head, he was a stroke risk

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.(1)

  • Vertebral arteries are vulnerable to mechanical stress between the atlas and axis, and subsequent vertebral arteries 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 recurrent stroke.
  • 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.

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 compression of the arteries. Please see our discussion below on DMX.
  • When the neck was stabilized with a neck collar, aneurysms shrank, recurrent strokes stopped. Please see our discussion below.

Something pressing on your vertebral arteries – Rotational Vertebral Artery Occlusion

This article will focus on one aspect of Vertebrobasilar insufficiency, that 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

Your journey to correcting your symptoms have likely introduced you to 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 a surgery that will remove part of a 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 supplies 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.


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.

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.

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.

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.


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 makes 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 in 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 vertebrae, but it is often related to the upper cervical spine.

In our clinics’ research published in The Open Orthopaedics Journal (2), 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 and 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.

Research and Treatments

The medical literature treats Vertebrobasilar insufficiency and Hunter Bow Syndrome as a “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 to 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 present by surgeons.

In the medical journal Stroke, (3) 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 of 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 a problem of 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. Maybe necessary for some patients. There is a price to pay for permanent ability to rotate 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

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 (4) of a young bow hunter 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 experience in the management of bow hunter’s syndrome. This research was published in the journal World Neurosurgery. (5)

  • “There were 14 patients referred to Barrow Neurological Institute with symptoms concerning for 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 include 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 (6).

“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.

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.

Non-surgical treatment – Cervical Spine Stability and Restoring Lordosis -Making a case for regeneration and repair of the spinal ligaments

The cervical spine has a natural curve. It acts as a spring or shock absorber for the head. When this curve is gone, injury, Joint Hypermobility Syndrome, or degenerative cervical disc disease

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, 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 long hold the neck in correct alignment.

In this section, we are going to talk about the realistic non-surgical options to the treatment of Vertebrobasilar insufficiency and its related symptoms.

Above we spoke briefly spoke about blood thinners and patient training to avoiding 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 to 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(7) 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 in the series of published research Caring Medical Regenerative Medicine Clinics 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 mis-alignment 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).

Cervical Instability Consequences

Research on cervical instability and Prolotherapy

Caring Medical Regenerative Medicine Clinics have published dozens of papers on Prolotherapy injections as a treatment in 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 2014 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 which 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 are 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.” (2)

Prolotherapy, the curve of the neck and blood flow

The Horrific Progression of Neck Degeneration with Unresolved Cervical Instability

In February 2016 a paper appeared in the Medical Science Monitor: international medical journal of experimental and clinical research.(8) 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 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 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 of in our over 25 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, and re-establish normal biomechanics and encourage the restoration of lordosis.

New Research: Correct the problems of loss of lordosis: immediately increase cerebral blood flow

In the medical journal Brain circulation (Jan-March 2019) (9), doctors wrote of 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 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.

If this article has helped you understand the problems of Vertebrobasilar insufficiency and you would like to explore Prolotherapy as a possible remedy, ask for help and information from our specialists

1 Komatsu K, Ozaki A, Iwasaki K, Matsumoto S. Bilateral Vertebral Artery Aneurysms at the Atlantoaxial Joint Level Causing Recurrent Stroke. Internal Medicine. 2016 Nov 15;55(22):3365-8. [Google Scholar]
Hauser R, Steilen D, Gordin K The Biology of Prolotherapy and Its Application in Clinical Cervical Spine Instability and Chronic Neck Pain: A Retrospective Study. European Journal of Preventive Medicine. Vol. 3, No. 4, 2015, pp. 85-102. doi: 10.11648/j.ejpm.20150304.11 [Google Scholar]
Choi KD, Choi JH, Kim JS, Kim HJ, Kim MJ, Lee TH, Lee H, Moon IS, Oh HJ, Kim JI. Rotational vertebral artery occlusion: mechanisms and long-term outcome. Stroke. 2013 Jan 1:STROKEAHA-113. [Google Scholar]
4 Sorensen BF. Bow hunter’s stroke. Neurosurgery. 1978 May 1;2(3):259-61. [Google Scholar]
5 Zaidi HA, Albuquerque FC, Chowdhry SA, Zabramski JM, Ducruet AF, Spetzler RF. Diagnosis and management of bow hunter’s syndrome: 15-year experience at Barrow Neurological Institute. World neurosurgery. 2014 Nov 1;82(5):733-8. [Google Scholar]
6 Snyder DJ, Neifert SN, Gal JS, Deutsch BC, Rothrock R, Hunter S, Caridi JM. Assessing Variability in In-Hospital Complication Rates Between Surgical Services for Patients Undergoing Posterior Cervical Decompression and Fusion. Spine. 2019 Feb 1;44(3):163-8.
7 Hauser R, Steilen-Matias D, Fisher P. Upper cervical instability of traumatic origin treated with dextrose prolotherapy: a case report. Journal of Prolotherapy. 2015;7:e932-e935.
8 Bulut MD, Alpayci M, Şenköy E, Bora A, Yazmalar L, Yavuz A, Gülşen İ. Decreased vertebral artery hemodynamics in patients with loss of cervical lordosis. Medical science monitor: international medical journal of experimental and clinical research. 2016;22:495. [Google Scholar]
9. Katz EA, Katz SB, Fedorchuk CA, Lightstone DF, Banach CJ, Podoll JD. Increase in cerebral blood flow indicated by increased cerebral arterial area and pixel intensity on brain magnetic resonance angiogram following correction of cervical lordosis. Brain Circulation. 2019 Jan 1;5(1):19. [Google Scholar]


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