Cranio-Cervical Instability (CCI)/Cranio-Vertebral Instability (CVI)

Overview of Cranio-Cervical Instability (CCI) also known as Cranio-Vertebral Instability (CVI)

DR PREM PILLAY
Senior Consultant Neurosurgeon, Expert in Cranio-Cervical Instability/Cranio-Vertebral Instability

Cranio-cervical instability (CCI) refers to excessive movement or instability at the junction between the skull and the upper cervical spine. This condition can occur in adults and children. The common symptoms include neck pain, headaches, dizziness and neurological symptoms. This condition can arise from congenital malformations, and connective tissue disorders such as Ehlers-Danlos Syndrome (EDS),  Down syndrome, Morquio syndrome. CCI/CVI is associated with a range of neurological and musculoskeletal symptoms

Symptoms and Signs

Common Symptoms

• Severe headache especially at the back of the head and neck pain are hallmark symptoms, often accompanied by neurological complaints including numbness, muscle weakness, difficulty in coordination and gait problems.
• Cervico-medullary symptoms such as vertigo, dizziness, imbalance, and walking difficulties are frequently reported.
• Cognitive difficulties include memory problems, Brain Fog, and concentration difficulties.
• Lower cranial nerve deficits may manifest as speech difficulties, dysphagia, sleep apnea and tinnitus.
• Spinal cord and nerve compression (Myelopathy and radiculopathy) can present as weakness, numbness, and sensory loss in the arms and legs.
• Autonomic symptoms like syncope, nausea, and orthostatic intolerance (fainting spells) are also described.

Medical Evaluation and Diagnosis is best carried out by a Neurosurgeon with expertise in this condition. It may be overlooked, misdiagnosed or ignored until the condition is more severe.

Clinical Signs

• Weakness in arms and legs (Quadriparesis) or quadriplegia in severe cases.
• Abnormal head posture (torticollis) and abnormal neurological examination findings.
• .Myelopathy may show up as gait imbalance, muscle tightness and weakness and increased reflexes (hyper-reflexia).
• In some cases, the clinical exam may be normal but an experienced Neurosurgeon can order the right and appropriate tests to find radiological evidence of instability

Diagnostic Tests

Imaging Modalities

• Dynamic X-rays and CT scans are primary tools for detecting instability, especially with flexion and extension views.
• MRI is used to assess spinal cord integrity and compression, and can be performed in weight-bearing, flexion, and extension positions for more detailed evaluation.
• Radiographic Parameters: The most frequently used measurements for diagnosis and surgical decision-making include:

• • Clivo-axial angle (CXA)
  • Harris measurement
  • Grabb–Mapstone–Oakes measurement
  • Angular displacement of C1 to C2.

• Atlanto-dental interval and basion-axial interval are also assessed, with recent research providing normative data for these measurements in healthy populations to improve diagnostic accuracy.

Treatment Options

Non-Surgical Management

• Observation and regular imaging are recommended for asymptomatic patients especially those without much radiological instability.
• Spine rehab management including physiotherapy and cervical collars may be used in select cases, particularly in children or adults with mild symptoms.
• Spine injections including nerves and facets injections to reduce inflammation and pain can be used for select patients.

Surgical Treatment

• Occipito-cervical fusion (OCF) or C1-C2 fusion are the main surgical interventions for patients with clear radiographic instability and concordant symptoms.
• Open reduction and stabilization are performed to correct deformity and restore stability, often using autografts for fusion.
• Surgical outcomes: Studies report significant improvements in pain, neurological function, and quality of life following surgery, with high patient satisfaction and low surgical morbidity.

Special Considerations

• Syndromic patients (e.g.,EDS,  Down syndrome, Morquio syndrome) require close neurological and radiological screening, with annual exams and imaging recommended for early detection.
• Sports participation: Patients without instability or neurological symptoms can participate in sports, while those with instability may require preventive stabilization.

Conclusion

Cranio-cervical instability is a complex condition with diverse symptoms and significant diagnostic challenges states Dr Prem Pillay. Dynamic imaging and specific radiographic measurements are essential for accurate diagnosis. No surgery treatment can be used for selected patients with mild symptoms. Surgical intervention, particularly occipito-cervical fusion, offers substantial benefits for appropriately selected patients.

Early recognition and diagnosis remains an important issue as this condition is often overlooked by most doctors.