Atlanto-occipital fusion or Occipitalization of atlas [C1]is the most common congenital abnormality of the upper cervical spine. It means partial or complete congenital fusion between the atlas and the base of the occiput.
Other names for atlanto-occipital fusion are occipitalization, occipitocervical Synostosis, assimilation of Atlas
The severity ranges from a complete bony fusion to a bony bridge or even a fibrous band. Occipitalization occurs because of failure of segmentation between the fourth occipital sclerotome and the first spinal sclerotome.
The incidence has been reported to be 1.4 to 2.5 per 1000 children. It affects both sexes equally. and affects males and females equally.
In 70% of the cases, atlanto-occipital fusion is associated with a congenital fusion between C2 and C3. Other associated congenital anomalies are
- Kyphosis and scoliosis
- Anomalies of the jaw
- Incomplete cleft of the nasal cartilage
- Cleft palate
- External ear deformities
- Cervical ribs
- Urinary tract anomalies
Clinical Findings
These patients have
- Low hairlines
- Torticollis
- Short necks
- Restricted neck movement.
- Dull, aching pain in the posterior occiput and the neck
- Episodic neck stiffness
The symptoms are similar to Klippel-Feil syndrome, Neurological symptoms usually occur in third and fourth decades and vary depending on the area of spinal cord impingement. If it is anterior, pyramidal tract signs and symptoms predominate, if the impingement is posterior, posterior column signs and symptoms [Paresthesiae, numbness, impairment of 2 point discrimination and vibration and conscious proprioception impairment} predominate.
Nystagmus is a common finding.
Cranial nerve involvement can cause diplopia, dysphagia, and auditory disturbances.
Vertebral artery involvement may result in syncope, seizures, vertigo, and an unsteady gait.
Radiographic Findings
Routine radiographs usually are difficult to interpret, and CT scan or MRI may be needed to show the occipitocervical fusion.
Most commonly, the anterior arch of the atlas is assimilated into the occiput and displaced posteriorly relative to the occiput.
About half of patients have a relative basilar impression due to loss of height of the atlas.
Posterior fusion usually is a small bony fringe or a fibrous band that frequently is not evident on a radiograph.
Atlantoaxial instability should be looked for by flexion and extension views of the neck.
Myelography or MRI can detect areas of encroachment on the spinal cord or medulla
Treatment of Atlanto-Occipital Fusion
Patients who have minor symptoms or become symptomatic after minor trauma or infection can be treated conservatively with immobilization in plaster, traction, or a cervical orthosis.
When neurological symptoms occur, cervical spine fusion or decompression is indicated.
Anterior symptoms usually are caused by a hypermobile odontoid, therefore preliminary reduction of the odontoid with traction, followed by fusion from the occiput to C2, relieves the symptoms.
If the odontoid is irreducible, excision of the odontoid may be taken.
Posterior signs and symptoms usually are caused by bony compression or compression from a dural band. Removal of the dural band is indicated when a band is documented by CT or MRI. Posterior fusion may be added to prevent instability.
MRI OF NY 9 Years old baby shows that everything around it is normal but there is fusion of the posterior arch of the atlas with occipital bone ,what may be the solution for my beloved baby
Bereket,
That would depend on the symptoms. Have you taken a consultation? The article above does suggest broad guidelines but for specific treatment, you would need to see a doctor in person.
I have Autonomic Dysreflexia. My BP is brittle ranging from 300 to 37 within 30 minutes and then I am fine. Diagnosed at Parkland-Dallas.
My grandfather was James McCune with our family having an overabundance of cases of McCune-Albright syndrome. I, my mother,
her sisters, and my cousins and my children and grandchildren all have
Café-au-lait pigmentation pigments at the nap of our necks or identical moles on our chest. Some have half-dollar size bumps on their skulls and I have extra bones in strange places. One cleft-palate and one closed-skin-spinal bifida. Most have Leiden Factor V and Major Autoimmune problems. Most women had miscarriages and placenta previa.
I believe I have Genetic Non-Alzheimer’s Dementia and that my mother, two aunts and grandmother may also have had it. It seems to be tied to having surgery.
I also have been diagnosed with Neurogenic Bladder.
Can all of this be connected??
Thank you,
Cecilia Bush
Cecilia Rodriguez-Bush,
Thanks for posting this. Your conditions are more likely to be looked after by general physician/neurologist/neurosurgeon. I am sorry I would not be able to comment on this.
Take care.
I just read your post above. I was born with a cleft palate. In 1995 I found out my C1 is congenitally fused to C-2. I have recently been having episodes where I feel like I moved and inch to one side but know I didn’t, along with a constant mild H/A not relieved with Ibuprofen. A CT showed Basilar Invagination from atlantoaxial instability. I was thinking I might have Klippel-Feil syndrome. I am wondering if you can tell me how I could get more info or how I can tell if it is this one you write about or the other. I am told my options are to wait for further neurological symptoms (my only one is hyperreflexia) then get my scull fused to my spine or I can do it now. Neither sounds ideal. I was told I would not be able to turn my head in any direction. Are there any Doctors in the Boston are who specialize in this stuff that you know of?
Oh and I do also have one elfish ear, my TMJ, mouth “the size of a 12 yr old”, M shaped posterior hairline, along with 1.75 in front hairline, burning feeling on my muscles just below my neck, stiff achy occiput area, had a recent new episode of ringing in one ear and buzzing/thudding in the other with both feeling pressure and my head felt like it was under water, the episode lasted 24 hours. Several months ago, I had 3 toes go numb for several hours, heat nor massage helped. Hopefully this helps you give me some imput. I really want to be sure I ask the right people for my options.
Carol,
I am not aware of the specialists in that area. Your medical system would be able to tell you better. You need someone who specializes in upper cervical surgery. Find one and discuss with the doctor to determine if you need surgery and if surgery could help you.
You would then decide yourself if you want to undergo surgery now or wait further.
I had answered you previous cooment before I saw this. It seems that you are beginning to have neural symptoms. You might need to take fresh investigations and then decide further course. Please do see a specialist. I am sorry I cannot recommend anybody because frankly I do not have any idea. I am sure your health system would be able to guide you.
Take care.
Thank you for taking the time to read this and reply.
Your welcome. I understand that was not much of help but best of luck.
My C1 is fused to my skull and C2 and C3 are fused together, all from birth. I am 35 years old and I’m in good physical shape. I have several episodes over the past year where my lower back has shifted and I have bulging discs. Could this be due to the deformities in my neck?
Luke,
What do you mean when you mention that your back has shifted!! Lower back problems are of its own and not due to neck issues.
Take care.
Is there a way to send you images from CT scan to see if I have atlanto-occipital fusion? I believe that I do from comparing my images to known fusions but all anyone ever notices or comments on on my scans are my C2-3 fusion and I have never had a single report even look at C1 for additional fusion.
Brandy,
CTs are quite sensitive to pick fusion. If people have not commented that you have, is there is a specific reason to believe that you have atlanto occipital fusion.
You can send images to contact at boneandspine dot com.
Thank you for your response Arun. I am going to try and figure out how to email the folder with imaging to you.