Let’s Not Miss the Forest for the Trees

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Neurospine. 2019;16(2):207-208
Publication date (electronic) : 2019 June 30
doi : https://doi.org/10.14245/ns.19edi.003
Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
Corresponding Author Seung-Jae Hyun Associate Editor of Neurospine E-mail: hyunsj@snu.ac.kr

Craniovertebral junction (CVJ) pathologies are extremely complex and frequently associated with various extra-CVJ problems such as cerebral- or cerebellar malformations, ventriculomegaly, craniosynostosis, intracranial hypertension, supratentorial crowding, Chiari malformation, cerebrospinal fluid obstruction, craniocephalic mismatch, small posterior fossa, syringobulbia, syringomyelia, tethered spinal cord, spinal cord malformation, lipomyelomeningocele, conus lipoma and scoliosis. It is not unusual that scoliosis resolved spontaneously following foramen magnum decompression (FMD) or spinal cord untethering. A meta-analysis study demonstrated that scoliotic curve magnitude will improve after surgical treatment such as FMD or syrinx shunting/drainage of the Chiari malformation in one third (37%) of patients, or curve progression will stabilize in 18% of patients and progress in one half [1].

The current Neurospine is presenting a special issue of CVJ on behalf of Asia Pacific Cervical Spine Society. There are 2 particular articles that we should not miss in the CVJ special issue. One would be “A Review of a New Clinical Entity of ‘Central Atlantoaxial Instability’: Expanding Horizons of Craniovertebral Junction Surgery” presented by a CVJ master, Professor Atul Goel [2]. As he already mentioned in the paper, for several decades’ abnormal alteration of atlantodental interval was considered to be the sole parameter to diagnose atlantoaxial instability on dynamic plain radiographs. However, he proposed a novel concept that atlantoaxial instability can be present even when there is no bony deformity or malalignment on dynamic imaging and the conventional and validated parameters that determine the presence of atlantoaxial instability are within the range of normal. For such instability, he proposed a new clinical entity of ‘central’ or ‘axial’ atlantoaxial instability (CAAD). Furthermore, he demonstrated several plausible evidences of relationship between CAAD and basilar invagination, Chiari formation, syringomyelia, ossified posterior longitudinal ligament, Hirayama disease.

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? It is always a great pleasure to see debating an issue in an academic fashion.

The proverb, “Do not miss the forest for the trees.” is helpful to diagnose CVJ pathologies adequately. The new concept of CAAD and the rebuttal for the concept would balance and expand our field of view so that we could not miss the forest for the trees. Additionally, I do recommend to expand our readers’ view from the cranial vault and brain to the sacrum and conus, when we meet a patient with CVJ pathology.

References

1. Hwang SW, Samdani AF, Jea A, et al. Outcomes of Chiari I-associated scoliosis after intervention: a meta-analysis of the pediatric literature. Childs Nerv Syst 2012;28:1213–9.
2. Goel A. A review of a new clinical entity of ‘central atlantoaxial instability’: expanding horizons of craniovertebral junction surgery. Neurospine 2019;16:186–94.
3. Deora H, Behari S, Sardhara J, et al. Is cervical stabilization for all cases of Chiari-I malformation an overkill? Evidence speaks louder than words! Neurospine 2019;16:195–206.

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