Decompression does not necessarily provide headache relief…: Neurology Today

Article in brief

A German study showed that large foramen decompression can effectively treat Chiari I malformation in patients with cough-related headache. But independent experts said medical treatment should be used first, and stress relief should be a last resort.

Decompression surgery is an effective treatment for Chiari I malformation (CIM) in patients with classic cough-related headaches, but surgery is not helpful for patients with other types of headaches, according to a retrospective review of cases from a German hospital.

Decompression of the foramen magnum is sometimes recommended when brain imaging detects CIM and a patient has cough headaches or other symptoms, but surgery becomes more controversial if the patient has symptoms of migraine or other types of heachache.

The German study, published in August in a headacheJournal of the International Headache Society, reviewed headache characteristics, radiological findings, and treatment outcomes for 65 adult patients with CIM, some with decompression and some not.

Decompression was effective in the cough headache associated with Chiari malformation I. The study concluded that the atypical headache response was less responsive and the causal relationship with Chiari 1 malformation remains uncertain. “For atypical headaches, decompression should only be considered after appropriate prophylactic treatment has failed and within a multidisciplinary approach involving a neurologist.”

The study authors noted that the diagnosis of CIM is not made clinically, but using magnetic resonance imaging. CIM is defined by a descending hernia of the cerebellar tonsil greater than or equal to 5 mm through the foramen magnum. It occurs in about 0.1 percent of adults, affects mostly women, and is often associated with syringomyelia and possibly scoliosis, the paper said.

Symptoms tend to begin in adulthood with the typical paroxysmal ‘cough headache’ – caused or exacerbated by laughing, coughing, or the Valsalva maneuver. [sic] They last seconds to a few minutes.” But what can be confusing is that migraine-like headaches with symptoms like sensory phobia, nausea, and tension-like headache (TTH) may also be associated with CIM. Also, not all people with CIM have headaches. Or they may experience symptoms such as lightheadedness, dizziness, and gait disturbances.

“When a patient has a disabling daily headache and a Chiari malformation, there are often other factors that may contribute to the headache, such as underlying predisposition to migraines, overuse of analgesics, or other factors. When these patients are offered surgery and then continue to have the same headaches, Every day without rest, it is frustrating for them and their service providers.” – Dr. Carrie Robertson

“Decompression of the foramen magnum is the treatment of choice for patients with debilitating symptoms and/or pronounced syringomyelia,” the research paper said. But the researchers said there is a need to learn more about how headache pathology affects treatment outcomes.

The study includes charts and interviews

The study was conducted by a team at Ludwig Maximilian University Hospital in Munich. It included a retrospective analysis supplemented by current telephone interviews with 65 patients (38 women and 27 men, average age <44) who underwent conservative (non-operative) or surgical treatment of CIM in hospital from 2010 through 2021. All had confirmed CIM By MRI, it is defined as descending tonsils greater than 5 mm.

The investigators extracted data from patients’ charts and conducted telephone interviews with patients in May 2021 using a structured questionnaire that included pre- and postoperative headache characteristics, frequency, severity, and type of acute headache medication used. Headache was the predominant symptom in 41 (63 percent) patients, with 21 patients reporting cough headache and 20 atypical headaches. Spinal MRI revealed syringomyelia in 23 (35.4 percent) of 65 patients, most often in those with headache.

Decompression (usually C1 laminectomy and tonsillectomy) was performed in 49 of 65 patients, with four patients presenting with postoperative complications (two wound healing disorders, hydrocephalus, and meningitis). There was no severe neurological deficit remaining. Reasons for not performing decompression included patient preference, mild symptoms, or contraindications.

After surgery, 30 patients reported subjective headache relief (87.7 percent), headache remained unchanged in two (4.9 percent), and exacerbated in three (7.3 percent). When headache outcomes from different biology were considered, cough headaches had the greatest improvements after surgery by measuring frequency, severity, and use of analgesics. The paper said patients with other types of headaches improved less.

Dennis C. Thunstedt, MD, and colleagues conclude that “larger descent of the tonsils before surgery is associated with greater reduction in postoperative headache severity.” The median preoperative tonsil descent was 12.2 (plus or minus 6.1 mm), which the researchers said was greater than what has been reported in other publications.

The study was limited, including the fact that it was retrospective and involved calling the patient to fill in missing data from the charts, with some patients being questioned for up to 10 years after surgery. The study also included small numbers. For example, the group of headache patients who did not have surgery totaled only six, precluding its use as an appropriate control group for the natural course of headache in CIM.

The researchers reported that “frequency, intensity, and use of analgesics were significantly reduced in cough headaches,” but less so in patients with atypical headaches. In 13 out of 18 cases of cough headache, for example, the cough headache resolved completely after surgery, but most individuals in the cough headache group still had some type of headache after surgery.

A comprehensive evaluation is required

Carrie Robertson, MD, associate professor of neurology at the Mayo Clinic in Rochester, Minnesota, said the study results are in line with what she’s experienced in her headache practice.

“After a patient has been diagnosed with a Chiari malformation, it may be tempting for them to assume that if it is ‘fixed,’ all their symptoms will be resolved. It is helpful to do studies like this to share with patients when they are trying to evaluate the pros and cons of surgery. This study shows that while Some patients have improvement in their headache, this is not true for everyone,” she said in an email interview.

Dr. Robertson said several issues should be taken into account when evaluating a patient whose MRI shows low cerebellar tonsils. The first question, she said, was, “Is this really a distortion of my choice or an imitation?”

“Both low intracranial pressure and high intracranial blood pressure can contribute to decreased cerebellar tonsils,” said Dr. Robertson. “If a patient has an undiagnosed cerebrospinal fluid leak that is misdiagnosed as a Chiari malformation and is decompressed, this can lead to a chronic headache syndrome that is often difficult to treat.”

She said the evaluation should also address whether headache symptoms were clearly caused by CIM. “When a patient has a disabling daily headache and Chiari malformation, there are often other factors that may contribute to the headache, such as underlying predisposition to migraine, overuse of analgesics, or other factors,” Dr. Robertson said. “When these patients are offered surgery and then continue to have the same daily headaches without relief, it is frustrating for them and their providers.”

Figure 2

“When we see patients with Chiari malformation on an MRI and they have headaches, it’s really important to characterize the headaches.” – Dr. Gregory Albert

She said, “If a patient has a Chiari malformation and an accompanying migraine, I will focus on medical treatment rather than decompression. Just in case of an isolated cough/Valsalva headache and not worrying about mimicking Chiari, I will continue with surgery.”

Dr. Robertson said stress relief is not without risks. “There are risks of infection, hematoma, cerebrospinal fluid leakage, and sometimes headache exacerbation,” she said.

Patients may discover they have CIM by accident if they have an MRI for some reason besides their headaches or because they have CIM, said Gregory Albert, MD, MPH, Lee and Bob Kress, chief of pediatric neurosurgery and chief of pediatric neurosurgery at Arkansas Children’s Hospital. They suffer from frequent headaches and are looking for an explanation. Dr. Albert said it’s not fully understood why some people with CIM don’t develop symptoms until adulthood, or maybe not at all.

“When we see patients with a Chiari malformation on an MRI who have a headache, it’s really important to identify the characteristics of the headache,” he said, although “it’s usually easy to tell if it’s a Chiari-type headache or not.”

Albert, who is also a professor of neurosurgery at the University of Arkansas for Medical Sciences, said it’s important for patients newly diagnosed with CIM “to be evaluated by a neurologist or other headache specialist to ensure they are medically managed.” He said the decision to have decompression surgery, whether in children or adults, is not being taken lightly.

“The recovery time can be prolonged. It can take three to five days in the hospital, and then they have to relax at home for a month or so.”

Dr. Albert said: “Surgery for debilitating Chiari-type headaches is very successful, however, less severe headaches or headaches that are not Chiari-type are likely to be better managed without surgery.”

In addition to headache, Chiari-related swallowing difficulties, obstructive sleep apnea, and the presence of syringomyelia also influence the decision to recommend surgery.


None of the sources mentioned in the story were disclosed.