Understanding Ponticulus Posticus
Ross Hauser, MD. Hauser Neck Center, Caring Medical Florida
Brian R. Hutcheson, DC. Hauser Neck Center, Caring Medical Florida
Your doctor told you about ponticulus posticus. He/she may have told you that this is a somewhat rare condition and it may or may not be the cause of your health issues. But you wanted to learn more because this may be why you have headache, migraine, double vision, dizziness or orofacial (mouth and face) pain.
Understanding Ponticulus Posticus
In advancing cervical spine instability and neck problems, and with seemingly no alternative, the posterior atlantooccipital ligament transforms itself into a bony structure to “bridge” over the foramen in a last attempt to prevent vertebral artery and suboccipital nerve compression. A last chance to fight off cervical instability.
The posterior atlantooccipital ligament is a protector of the groove where the vertebral artery passes at the C1. “Ponticulus posticus,” is a “little posterior bridge” that is trying to prevent vertebral artery and suboccipital nerve compression –
Ponticulus posticus, also referred to as arcuate foramen or Kimmerle’s anomaly, is what it’s Latin name implies, “Ponticulus posticus,” a “little posterior bridge.” How did you develop this bony little bridge abnormality at the posterior of the atlas/C1 vertebra?
In simplest terms, the little bony bridge is a petrified ligament. But instead of the ligament turning into stone, the ligament turned into bone. Specifically, the ponticulus posticus formed as a result of ossification of the posterior atlantooccipital ligament. Why did this happen?
The posterior atlantooccipital ligament is a protector of the groove where the vertebral artery passes at the C1. When there is upper cervical instability, specifically at the C1 or Atlas, the vertebral artery and the suboccipital nerve which both travel through the C1 foramen (opening) can be compressed. The ligament which is not strong enough to protect this opening if instability is present, continuously weakens and becomes damaged in its attempt to provide this protection. With seemingly no alternative, the ligament transforms itself into a bony structure to “bridge” over the foramen in a last attempt to prevent vertebral artery and the suboccipital nerve compression. This of course is not optimum for the patient. The ligaments serve to provide strong, natural, cervical motion when the ligament turns into bone, it is creating its own fusion, such as it is with bone spurs.
You may have learned about the ponticulus posticus from an incidental MRI or CT Scan – it may have been ignored or it may be the reason for your symptoms.
For many people, like yourself probably, you learned about the ponticulus posticus from an incidental MRI or CT Scan. This means that no one was looking for this but the little bony bridge showed up at your C1 on imaging.
In the video below, Ross Hauser, MD explains: A summary transcript is below the video:
- Ponticulus posticus can be missed on x-rays and even digital motion x-ray (DMX) and often it’s just discarded as kind of a normal variant. In our office we see ponticulus posticus in some patients. For many of them, this is not a normal variant but the cause of many of their problem symptoms. (Headache, migraine, double vision, dizziness or orofacial (mouth and face) pain.)
- At 0:40 of the video the ponticulus posticus structure is identified in the patient’s digital motion x-ray.
- Surrounding the ponticulus posticus are a lot of vital structures, such as the vertebral artery and the suboccipital nerve. These structures can be squeezed or compressed by the ponticulus posticus, this is why we do not see this as a normal variant in many people.
- In this particular patient, they have ponticulus posticus only on the right side. Some people develop ponticulus posticus on both sides of the cervical column. In this person, being on the right side, the symptoms they develop would be right side facial pain, migraines, etc.
- At 1:13 of the video, the patient starts to move their neck to allow us to see their cervical spine in motion.
- At its location on the C1 vertebrae or superior articulate to the posterolateral part of the atlas (C1), you can see how this patient’s neck movements the ponticulus posticus can come into contact with the C1 nerve root on the right side and the right side vertebral artery. So when this patient bends forward or back you could see the ponticulus posticus gets closer to the occiput with one of the movements and gets closer to the atlas with one of the movements that means that on the side that it is there is a narrowed space and compression of the vertebral artery and the C1 nerve root.
- Especially noted is that C1 nerve innervates the dura which covers the brain so if you have like unexplained pain on the right side (as this patient may have) or deep pain, a weird pain such as in between the eyebrows or in the face, or migraine headaches on one side there can be an association with the Ponticulus posticus.
Research: Ponticulus Posticus in symptomatic and asymptomatic patients
As mentioned above, You may have learned about the ponticulus posticus from an incidental MRI or CT Scan – it may have been ignored or it may be the reason for your symptoms. In the DMX image, we saw in the above video, we saw how the ponticulus posticus could impact the C1 nerve root and the vertebral artery. This is not always an easy observation to make. Ponticulus posticus
The goal of this study was to substantiate whether the ponticulus posticus was the possible cause of chronic tension-type headaches and migraine.
Writing in the Journal of Clinical and Diagnostic Research, (1) researchers investigated the prevalence and morphological (the interaction between the bony, nerves and soft-tissue structures) features of ponticulus posticus in symptomatic and asymptomatic patients. The goal of this study was to substantiate whether the ponticulus posticus was the possible cause of chronic tension-type headaches and migraine.
This study refers to:
- Partial Ponticulus Posticus – unilateral one-side
- Complete Ponticulus Posticus – bilateral – both sides
The researchers examined five hundred patients for the presence and type of ponticulus posticus. All the patients in whom ponticulus posticus was present in either partial or complete form were further studied for symptoms like chronic tension type headache, orofacial pain or diagnosed migraine.
- Among the sample of 500 cases, partial ponticulus posticus was found in 302 patients (60%) (Males 48% and Females 52%).
- Complete variant was found in 40 cases (8%) (Males 65% and females 35% both, who were in the age group of 16-45 years),
- In partial Ponticulus Posticus, 42 patients (14%) were found to be symptomatic. In complete form, 32 patients (78%) were found to be symptomatic.
- Symptoms were mainly in the form of migraine or chronic type of headache.
The researchers concluded: “According to our study, partial form of ponticulus posticus was found to be more prevalent as compared to complete form in the (study) population and complete form of ponticulus posticus can be considered as possible cause for chronic tension type headache, orofacial pain and migraine.
Surgery and non-surgical treatments
There is not a lot of research on how to treat ponticulus posticus, As noted above, for many doctors this is an incidental finding and it does not require treatment. This is not true for every patient.
Here is a study from December 2017, published in the Journal of Craniovertebral Junction and Spine. (2) Here surgeons discuss ponticulus posticus described as Kimmerle’s anomaly.
- Reports on the surgical treatment of Kimmerle anomaly are rare.
- Surgical treatment of vertebral artery compression in patients with Kimmerle anomaly is preferable in cases where conservative treatment is inefficient. A minimally invasive procedure can be an alternative to the routine open surgery procedure.
Ponticulus lateralis and compression of the vertebral artery
The same research team published a second study in September 2018. (3) Writing in the journal World Neurosurgery, the surgeons made these observations:
Expanatory note: The term ponticulus lateralis refers to when the ponticulus posticus bony bridge takes a vertical spike upwards to directly compress the vertebral artery.
- In some cases, the bony ridge may also be formed at the level of the vertebral artery emerging from the transverse process of the С1 vertebra (this is ponticulus lateralis). Simultaneous 1-sided formation of ponticulus lateralis and ponticulus posticus is very rare. Data concerning surgical treatment for compression of the vertebral artery owing to ponticulus lateralis are lacking.
In this study a case is demonstrated in a A 34-year-old woman who had significant dizziness to the point of losing consciousness while rotating her head to the left. Computed tomography angiography of the cervical spine revealed С1 anomaly with the formation of ponticulus lateralis and ponticulus posticus with acute-angled С-shaped kinking of the vertebral artery.
- In this patient surgery was able to help with her pain by removing the compression of the С1 spinal root and alleviated her bow hunter’s syndrome (losing consciousness) when she turned her head.
- The surgeons of this study suggested that this was the first report on the surgical treatment of vertebral artery compression owing to ponticulus lateralis and ponticulus posticus.
What should be pointed out is that surgery, specifically for ponticulus lateralis and ponticulus posticus, has little research behind it and is rarely performed.
Bow hunter’s syndrome
I have an extensive article: Treating Vertebrobasilar insufficiency – Bow hunter’s syndrome. Everytime I turn my head I get dizzy. Sometimes I almost pass out. Here I discuss the complexity and challenges of cervical neck instability treatment which 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.
As discussed in this article, there can be an association between ponticulus posticus and your symptoms that can include you passing out when you turn your head to one side, migraine headaches, facial pain, visual disturbances, among other problems. So for many people, this is not a benign finding and it could be a significant finding in resolving your particular problems.
Determining blood flow to the brain
At the Hauser Neck Center at Caring Medical Florida, we can utilize transcranial doppler (TCD) and extracranial doppler (ECD) ultrasound examination to assess proper blood flow during positional changes of the neck.
In this video, a when this patient is in a neutral position, head up, looking straight ahead, blood flow through the arteries can be seen and heard. When the patient is asked to extend their head backwards and to the left, an clear and audible difference in the blood flow can be heard. This is demonstrated at the start of the video.
Determining at which head position decreased blood flow occurs can help us determine treatment for vertebrobasilar insufficiency. In the case of this article, is the ponticulus posticus pressing on the vertebral artery, if it is, at which head position? In the video above we saw the ponticulus posticus banging against the occiput at the base of the skull and the C1.
Demonstration of non-surgical Prolotherapy treatment option
Caring Medical has published dozens of papers on Prolotherapy injections as a treatment in difficult to treat musculoskeletal disorders. In this article Prolotherapy is demonstrated as a treatment to address upper cervical instability in cases of ponticulus posticus and without ponticulus posticus.
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.
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.
In video below, DMX displays Prolotherapy before and after treatments that resolved problems of a pinched nerve in the cervical spine
- In this video, we are using a Digital Motion X-Ray (DMX) to illustrate a complete resolution of a pinched nerve in the neck and accompanying symptoms of cervical radiculopathy.
- A before digital motion x-ray at 0:11
- At 0:18 the DMX reveals completely closed neural foramina and a partially closed neural foramina
- At 0:34 DXM three months later after this patient had received two Prolotherapy treatments
- At 0:46 the previously completely closed neural foramina is now opening more, releasing pressure on the nerve
- At 1:00 another DMX two months later and after this patient had received four Prolotherapy treatments
- At 1:14 the previously completely closed neural foramina is now opening normally during motion
If you have questions and would like to discuss your cervical spine issues with our staff you can get help and information from us.
1 Chitroda PK, Katti G, Baba IA, Najmudin M, Ghali SR, Kalmath B, G V. Ponticulus posticus on the posterior arch of atlas, prevalence analysis in symptomatic and asymptomatic patients of gulbarga population. J Clin Diagn Res. 2013 Dec;7(12):3044-7. doi: 10.7860/JCDR/2013/6795.3847. Epub 2013 Dec 15. PMID: 24551723; PMCID: PMC3919343. [Google Scholar]
2 Lvov I, Lukianchikov V, Grin A, Sytnik A, Polunina N, Krylov V. Minimally invasive surgical treatment for Kimmerle anomaly. J Craniovertebr Junction Spine. 2017 Oct-Dec;8(4):359-363. doi: 10.4103/jcvjs.JCVJS_73_17. PMID: 29403250; PMCID: PMC5763595. [Google Scholar]
3 Lukianchikov V, Lvov I, Grin A, Kordonskiy A, Polunina N, Krylov V. Minimally Invasive Surgical Treatment for Vertebral Artery Compression in a Patient with One-Sided Ponticulus Posticus and Ponticulus Lateralis. World neurosurgery. 2018 Sep 1;117:97-102. [Google Scholar]