Chiari 1 Malformation with Secondary Cervicothoracic Syringomyelia

A 47-year-old black female presented with a 2-day history of right-sided facial and hand numbness. She described it as a burning sensation that spread to the right arm, neck, and right toes. 

History. Previously she had been experiencing right shoulder discomfort of 5 months duration and stated that despite aggressive physical therapy and use of NSAIDs, her shoulder pain was increasing in intensity. She denied any dizziness, loss of consciousness, headaches, dysphagia, or weakness in her extremities. 

Physical examination. Her neurological examination was significant for decreased pin and touch sensation in the right upper extremity, decreased reflexes in biceps, brachioradialis, and fasciculation of her tongue. 

Diagnostic testing. MRI of the cervical spine with and without contrast was significant for a Chiari 1 malformation extending down to C2 level with an associated 13 mm syrinx (Figure 1). An MRI of thoracic spine was also performed, which showed the syrinx extending to the T7 level (Figure 2). 

Discussion. Chiari 1 malformation, defined as downward herniation of cerebellar tonsils through foramen magnum, can be associated with a non-communicating hydrocephalus or cervicothoracic syringomyelia. Those associated with syringomyelia can present with various neurologic symptoms, which often include headaches. When neurologic examination findings raise high suspicion for the disease, an MRI is performed as the imaging modality of choice. 

Once diagnosis is confirmed, those individuals with mild symptoms can be treated in a conservative fashion; however, when symptoms become more severe and persistent, foramen magnum decompression is the treatment of choice.¹ After decompression, changes can be seen on imaging, such as cerebellar tonsils and brainstem adjusting back to baseline 6 months post-surgery.² Changes can also be seen on imaging with regards to the associated syrinx with its resolution on MRI.³ These changes can all be translated to the clinical improvement of the patient after surgical treatment. 

More than half have a reduction in headaches and if weakness is present, most patients have significant increase in their muscle strength. Sensory function, however, may not return to baseline. Despite improvements in a majority of patients postoperatively there is also data that shows neurological recurrence rates of 7% after 5 years, and reaching up to 8.7% after 10 years postoperatively.¹ Although rare, postoperative infections, hemorrhage, adhesions, cerebrospinal fluid leakage, and hydrocephalus are among the most commonly reported complications associated with Chiari decompression. 

Outcome of the case. Due to brainstem compression at the cervicomedullary junction, the patient underwent suboccipital craniectomy, C1-C2 laminectomy, and decompression of Chiari malformation with allograft duraplasty. Her surgery was uncomplicated and her symptoms significantly improved over several months showing a decline in the burning and numbness sensations of her right side.

REFERENCES:

1. Klekamp J. Surgical treatment of Chiari I malformation--analysis of intraoperative findings, complications, and outcome for 371 foramen magnum decompressions. Neurosurgery. 2012;71(2):365-380; discussion 380.
2. Heiss JD, Suffredini G, Bakhtian KD, et al. Normalization of hindbrain morphology after decompression of Chiari malformation Type I. J Neurosurg. 2012;117(5):942-946.
3. Vakharia VN, Guilfoyle MR, Laing RJ. Prospective study of outcome of foramen magnum decompressions in patients with syrinx and non-syrinx associated Chiari malformations. Br J Neurosurg. 2012;26(1):7-11.