[Atlas block and alar ligament lesion-Underestimated or overrated?]

Background: Disorders of the upper cervical spine, most notably lesions of the alar ligament and atlas block, are associated with numerous symptoms, especially as reported in the lay press. Thus, physicians are often confronted with patients who see in them a monocausal origin of complex complaints and hope for a quick remedy.

Objective: This review article presents the currently available evidence-based literature on atlas block and alar ligament lesions in order to adequately appreciate their significance.

Material and methods: Summary and critical evaluation of an extensive review of the literature on the diagnostics, clinical presentation, and treatment of disorders of the upper cervical spine.

Results: The current literature shows that alar ligament lesions are caused only by extremely high-speed trauma and that the reliability of their detection on magnetic resonance imaging (MRI) is moderate at best. As several studies have failed to demonstrate a correlation between symptoms and abnormalities of the alar ligaments on MRI, surgical stabilization of the upper cervical joints is not indicated. The diversity of symptoms associated with atlas block may be explained by the convergence of afferent neurons originating in C1-C3 on several cranial nerve nuclei found in neuroanatomical studies, but this association has yet to be proven. First studies show that highly significant improvements in cervical pain and range of motion can be achieved by means of manual therapy of the upper cervical spine with lasting effects even after 6 months.

Conclusion: The importance of alar ligament lesions has often been overrated in the past; however, a more nuanced multifactorial understanding of the disorder should be conveyed to the patient. An atlas block should be considered mainly as a possible cause of pain and restricted range of motion of the cervical spine and in this context manual therapy can be an effective treatment option.