Advanced Treatment for Craniocervical Instability
Craniocervical instability (CCI) is a condition where the cervical spine is unable to maintain adequate alignment and support of the cranium during certain movements, causing the head to “wobble.” The underlying cause of CCI is structural: one or more bony and/or ligamentous anomalies involved in the craniocervical junction prevent normal range of movement of the head and neck. In many instances, the instability reduces the cervical spaces through which the brainstem and spinal cord pass, causing pressure on the delicate soft tissue, with neurologic and vascular consequences as well. Cushing Neuroscience Institute’s Chiari Institute is one of the leading centers for the evaluation and treatment of CCI in the country. While some patients with CCI will improve sufficiently with conservative non-surgical treatment, the remainder require complex surgical correction and realignment. The sooner such interventions are begun the better the outcome; CCI tends to worsen over time, eventually causing irreversible damage to spinal nerves and muscles and loss of physical strength and mobility.
Adding to the challenge for primary physicians and pediatricians, identifying CCI in a patient can be difficult. The first symptoms tend to be subtle, ambiguous and intermittent; younger patients in particular may have difficulty describing the various sensations they experience. Since 50 percent of diagnosed CCI cases are associated with certain congenital disorders — Down syndrome, congenital scoliosis, cerebral palsy, ankylosing spondylitis, osteogenesis imperfecta, neurofibromatosis and connective tissue disorders such as Ehler’s-Danlos — special attention should be paid to any member of this cohort exhibiting one or more symptoms. The most common precursor of accidental CCI is whiplash — the dynamic extensions and flexions of head and neck associated with automobile crashes and contact sports. In rare instances, the cause is iatrogenic — the result of bone removal during a prior surgery to cut away a tumor or treat Chiari syndrome. Ironically, the squeezing of the parts of the brain through the hole at the base of the skull, referred to as the Arnold Chiari or Chiari I malformation, is sometimes taken to be the cause of signs and symptoms when actually the squeezing results from craniocervical instability.
Common CCI symptoms to look for in patients with otherwise undiagnosed cervical complaints include headaches in the occipital space at the back of the neck and skull, painful neck, torticollis, tingling and numbness in the upper extremities, muscle weakness, difficulty walking, difficulty swallowing, sleep apnea, snoring, drooling, progressive hearing loss and recurring fatigue. Drop attacks, provoked by specific movements of the head and neck that cause temporary ischemia, are another. In the pediatric and adolescent populations where physical growth can play a part in the timing of CCI onset, an indicator may be as simple as an increasing reluctance to participate in play.
Primary care physicians who suspect CCI in a patient should initially order an MRI of the area to visualize the anatomy and rule out other causes. At the Chiari Institute, experienced neurologists and neurosurgeons can determine which patients are likely to improve with conservative intervention; these patients are prescribed physical therapy, strengthening routines, relaxation training and medications. Patients with acute or multiple CCI symptoms that will not respond to therapy alone are considered for surgical stabilization and/or fixation.
At the Chiari Institute, all CCI surgery is performed by a team of neurosurgeons. Each patient’s anatomy is unique, so each surgery requires extensive, pre-planned imaging and bioengineering analysis to determine the patient’s operative stabilization and fixation. Days before the surgery, the patient goes through several hours of advanced dynamic MRI. This pinpoints the location of millimeter-thin compressions that are causing brain and spinal cord symptoms. We also measure several critical craniocervical angles against norms; these provide a basis for intraoperative surgical stabilization and fixation.
The surgery itself is very delicate, typically taking 5-6 hours. After the patient undergoes general anesthesia, the surgical team makes one opening, approximately 10-15 inches in length from the top of the head to the back of the neck. As the surgical field is highly trafficked with vertebral arteries and veins, the brainstem and critical cranial nerves, each step in the realignment of bones, the remodeling of angles and in the relief of compression points requires exquisite surgical precision. A unique feature of our approach is the use of intraoperative ultrasound during surgery, in addition to continuous brainstem and spinal cord monitoring. This guides precise adjustments during our realigning and stabilization of the cranium on the cervical spine. Postoperative recovery in the hospital takes 4-5 days, followed by rehabilitation and a gradual return to normal activities.