This is a slightly more technical piece with a lot of jargon – my apologies. It is geared toward people on the path to determining if they have cranial cervical instability and have some knowledge of this topic. I am happy to answer any questions readers may have.
My neurosurgeon offered two “appetizers” to go along with my detethering surgery (called SFT) this past August: invasive surgical traction (ICT) and the intracranial pressure bolt test (ICP bolt test). Nothing like getting a few holes drilled into your head before getting your spine cut. Are we having fun yet?
During my initial consultation with Dr. Bolognese, he focused exclusively on tethered cord syndrome. He said we could discuss instability in my craniocervical junction (CCJ) after SFT surgery. There is a good reason; releasing tension in the spinal cord often results in changes at the CCJ.
Think of the tether as holding the head and neck in place, like a wooden push puppet. A tethered cord could help add stability by pulling down on the brainstem. But it cuts both ways – tension in the spinal cord can also cause many head, neck, and shoulder symptoms. My tether caused many of these symptoms, as I discovered after my SFT surgery. Comparing a pre-surgical baseline with a post-SFT traction response would give me a sense of what my surgical future holds.
Invasive cervical traction
The first procedure on the docket was ICT, an invasive test involving inserting pins into the skull behind the ears to attach the traction halo, a metal handle that looks like ice block tongs. After a test dose of propofol, the anesthesiologist put me to sleep. The next thing I knew, Dr. Bolognese’s PA, Phil, woke me up and chatted with me about evolutionary biology until I was lucid enough to do the test. I could not feel the halo! Dr. B instructed Phil to add weights, starting at 20 pounds, working up to 35 pounds, using a pulley system above my head.
Before the test, I was unclear about which symptoms to focus on during traction and how to quantify them. A friend warned me not to get into symptom nuance. I recall Jennifer Brea had central apnea on her list. Other friends chose POTS, swallowing difficulties, and other symptoms I do not have. For two years, I used the absence of these symptoms as further evidence that I did not have cranial cervical instability (CCI). This disease manifests differently across people; the symptoms people select for ICT reflect this.
I selected some symptoms and typed them into my phone in case I drew a blank in my propofol daze: suboccipital (base of the skull) headache, brain fog, orthostatic intolerance (OI), fatigue, and shortness of breath. These seemed to match up well with the ones Dr. Bolognese had on his list. I do not have a Chiari malformation, so we did not focus on symptoms related to this condition.
The other aspect of the test I fretted over was how to quantify symptom improvements. I knew Dr. B would ask me to use percentages to measure changes during traction. I did not anticipate significant improvements and wondered how to differentiate between, say, a 20% vs. 30% improvement. I told Dr. B I would err on the side of underestimating to avoid inflating my response.
During the test, Dr. B’s team used fluoroscopy imaging to visualize my cranial cervical junction (CCJ) in response to traction. Fluoroscopy allows Dr. B to take dynamic measurements and pair his findings with symptom responses. He bases his decision to offer cranial cervical fusion (CCF) surgery on pathological measures and a clear positive response to invasive traction. I have seen him turn away several patients positive for CCI on imaging because they did not show an overwhelmingly positive reaction to traction.
Diagnosis
Dr. Bologonese shared my traction results when he made his rounds after SFT surgery. I was still high as a kite (Dr. B’s words) on surgery drugs and pain meds, but thankfully my husband recorded the most important parts of our conversation. Dr. B diagnosed me with horizontal cranial cervical instability, but he also suspects vertical instability. People with this latter condition describe feeling like they have a heavy bobblehead that crushes the brainstem and neck. My morphometrics did not support this diagnosis, despite Dr. B suspecting it because orthostatic intolerance is one of my worst symptoms.
Dr. Bolognese assesses vertical instability by looking at the change in the basion-dens interval (BDI) during ICT. The BDI is the distance between the basion and the tip of the dens. The basion is located on the skull and is the midpoint of the anterior margin of the foramen magnum. The dens (also called the odontoid) is a process (sticky-outy thing) on the C2 vertebra that forms a joint with C1. BDI measures the distance between the basion and the dens (see Distance 1 on the fluoroscopy image above). With vertical CCI, this distance increases during traction. Sometimes vertical CCI can be diagnosed from an MRI, but typically it is the dynamic measurement that is most indicative. Click here for a summary of measures used to assess CCI.
The measurements below don’t seem very compelling for a CCI diagnosis, whether horizontal or vertical CCI. My change in the BDI measure was well within the margin of error (Table 1). Dr. Bolognese said sometimes vertical instability can be masked by tethered cord syndrome because, presumably, the tether stabilizes the cranium. He wants me to return to do another round of traction a few months after my SFT surgery.
The other measures look unremarkable to me as well (Table 1). The BAI – a measure of horizontal instability – change is 2.7 (see Distance 4 on the image above), which seems small compared to reports I’ve seen. Same with the Grabb measure (see Distance 5 above). My CXA angle (see Angle 6) is only borderline pathological.
Despite my less than convincing morphometrics, my response to traction was overwhelmingly positive (Table 2). Dr. Bolognese asked, “How is your brain fog?” I could not believe my experience, and I replied, “How about GONE?” Same for OI – for the first time in years, it felt normal to be upright! I told Dr. B that I felt like going for a long walk while talking about immunology. I felt incredible joy having a clear brain and boundless energy! Even my vision improved, and I felt better than I had in 15 yrs – a reminder that I am still inside this broken body. I was euphoric, and I felt a deep sense of equanimity, trusting that everything would be OK.
I am unsure what tipped the scales in favor of a CCI diagnosis, but it likely had to do with the combined measurements and improvements during ICT. I hope to get more clarity when I am ready to meet with Dr. B again.
When I asked about regenerative medicine approaches and PT, Dr. Bolognese all but told me not to waste my money and that I would eventually need surgery anyway. Dr. B said he is not opposed to these modalities but that he rarely sees lasting benefits in people with even moderate CCI, a category he places me in (he said these therapies are worth trying in mild cases). Dr. Bolognese has hope in regenerative methods but doesn’t think the science is there yet. I told him the irony is that I could get the surgery for free (I have Medicare and a good supplemental plan) but would have to pay tens of thousands of dollars for regenerative medicine with no guarantee. I hate that the less invasive procedure is the more expensive one.
Next steps?
I am only two months post-SFT surgery and still trying to find my way after neurosurgery. My neck hasn’t worsened since surgery, as it does for many. I had complete remission of head and neck symptoms for two weeks after SFT, but they have returned, not as extreme as pre-surgery.
I am growing accustomed to living with CCI and am managing it better now that I understand its contours. It bothers me more as the day goes on and the more upright I am. I am still enjoying some gains on the OI front. I feel like a hot mess some days, but an inner pilot light has been lit and flickers. Will my CCI worsen the farther I get away from my SFT surgery? Time will tell.
I promised myself I would not be silly and try to convince myself I have a good quality of life if I am bedridden by CCI. Managing CCI centers on avoiding exacerbating factors. I can no longer go on car trips with my family. Instead, I stay home and take care of the dogs. I may miss Thanksgiving again this year. It saddens me to see my husband and son going off to have fun while I stay at home, but I am also happy for them. Then again, staying home is all I want these days because it offers safety. I can control my environment better at home and am surprisingly OK with my own company.
I will know if and when it is time to return to NY to see Dr. Bolognese for another round of traction. I am ambivalent about scheduling surgery while I am still somewhat functional. In the meantime, I am getting a new set of neck MRIs to see what has happened since I last had one done in 2018. The radiologist mentioned cervical spondylitis (arthritis) consistent with age, but I had no (head and neck) symptoms back then. What, if anything, has changed? I’ll find out in a couple of weeks.
My GP reminded me that even if the new images show spondylitis, we still can’t be sure about what is driving my head and neck symptoms – CCI or cervical spondylitis. I suppose my next step is to determine a path that would address both problems.
Briefly, my ICP bolt experience.
I had no reason to believe that I would have an abnormal bolt test, though Dr. Carroll suggested I could have a mixed picture of intracranial hypertension and hypotension, the test was on offer, and I was there, so why not?
After ICT, Dr. B’s team put me to sleep again and installed an intracranial bolt in my skull. This involves drilling a small borehole into the skull and placing a sensor inside the skull that measures cerebral spinal fluid pressure. They leave the bolt in for 24 hours so the PAs can collect data 2-3 times during that period. This involves staff from the neurosurgery team coming to look at pressure changes during orthostasis, e.g., sitting up and standing.
My test was utterly normal, meaning that my cerebral spinal fluid pressure responded as expected. Be thankful for the small mercies.
Since I had a sensor inside my skull, the team kept me in the hospital overnight and took the bolt out during SFT surgery the next day. The bolt test was more challenging than ICT and SFT for me. Many people told me that I wouldn’t feel a thing, except that I did. The gains I experienced during ICT lasted until the evening when a punishing rebound headache set in. The bolt started to hurt, adding to my head pain. A steady diet of 10 mg of oxy and Zofran was not enough to control the pain and nausea. I was miserable and vomited throughout the night.
Thankfully, when I woke up from SFT, the pain was gone entirely.
Some acronyms used in this piece:
SFT – sectioning of the filum terminale, aka detethering surgery
CCJ – Cranial cervical junction, where the skull meets the cervical spine
ICT – Invasive cervical traction
ICP bolt – Intracranial bolt test
CCI – Cranial cervical instability
CCF – Cranial cervical fusion, a surgery that fuses the skull to C1 and C2 vertebrae; an intervention to correct for CCI
More blogs on my surgery experience:
Frozen in Amber 
Thank you so much for sharing your experiences. I can’t tell you how much I have appreciated your generosity these past few years. I’m sorry that you go through all of this. You don’t deserve to.
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