Is Cervical Stabilization for All Cases of Chiari-I Malformation an Overkill? Evidence Speaks Louder Than Words!

Abstract

Chiari I malformation is characterized by the downward displacement of cerebellar tonsils through the foramen magnum. While discussing the treatment options for Chiari I malformation, the points of focus include: (1) Has the well-established procedure of posterior fossa decompression become outdated and has been replaced by posterior C1-2 stabilization in every case? (2) In case posterior stabilization is required, should a C1-2 stabilization, rather than an occipitocervical fusion, be the only procedure recommended? The review of literature revealed that when there is bony instability like atlantoaxial dislocation (AAD), occipito-atlanto-axial facet joint asymmetry or basilar invagination (BI) associated with Chiari I malformation, one should address the anterior bony compression as well as perform stabilization. This takes care of the compromised canal at the foramen magnum and re-establishes the cerebrospinal fluid flow along the craniospinal axis; and also provides treatment for CVJ instability. In the cases with a pure Chiari I malformation without AAD or BI and with completely symmetrical C1-2 joints, however, posterior fossa decompression with or without duroplasty is sufficient to bring about neurological improvement. The latter subset of cases with pure Chiari I malformation have, thus, shown significant (> 70%) rates of neurological improvement with posterior fossa decompression alone. A C1-2 posterior stabilization is a more stable construct due to the strong bony purchase provided by the C1-2 lateral masses and the short lever arm of the construct. However, in the cases with significant bleeding from paravertebral venous plexus; a very high BI, condylar hypoplasia and occipitalized atlas; gross C1-2 rotation or vertical C1-2 joints with unilateral C1 or C2 facet hypoplasia, as well as the presence of subaxial scoliosis; maldevelopment of the lateral masses and facet joints (as in very young patients); or, the artery lying just posterior to the C1-2 facet joint capsule (being endangered by the C1-2 stabilization procedure), it may be safer to perform an occipitocervical rather than a C1-2 fusion.

Chiari malformation type I and basilar invagination originating from atlantoaxial instability: a literature review and critical analysis

“…However, previous studies clearly demonstrated clinical efficacy with decompression alone and probably remains a suitable treatment option for CM with no signs of instability [11,54]. In summary, we agree with Deora and colleagues that in patients with pure CM with symmetrical C1/2 joints and no signs of instability, PFD and duraplasty is an established, effective, and safe treatment option with excellent long-term outcome [18,28,62,89]. In patients with instability, C1-2 fusion with distraction or OCF with or without transoral decompression in selected cases are potential treatment options that have to be considered in this patient population.…”

Craniovertebral Junction Anomalies: Changing Paradigms, Shifting Perceptions: Where Are We and Where Are We Going?

“…The Only Treatment for Chiari Malformation Is Foramen Magnum Decompression With or Without Duroplasty: Behari et al [9] in his impressive review of literature has shown significant improvement (upto 70%) may be achieved both with foramen magnum with or without duroplasty [10]. He also stressed the low mortality of this procedure (<1%).…”

Let’s Not Miss the Forest for the Trees

“…The other top pick would be “Is Cervical Stabilization for All Cases of Chiari-I Malformation an Overkill? Evidence Speaks Louder Than Words!” presented by another master, Professor Sanjay Behari and Dr. Deora et al [3] The authors have answered for the 2 fundamental questions in a scientific way: (1) Has the FMD become outdated and has been replaced by posterior C1–2 stabilization in every case? and (2) In case posterior stabilization is required, should a C1–2 stabilization, rather than an occipitocervical fusion, be the only procedure recommended?…”