Home | About JCVJS | Editorial board | Ahead of print | Current Issue | Archives | Instructions | Subscribe | Advertise | Contact us |   Login 
Journal of Craniovertebral Junction and Spine
Search Articles   
Advanced search   

   Table of Contents  
Year : 2017  |  Volume : 8  |  Issue : 1  |  Page : 1-2  

Is Chiari a “formation” or a “malformation?”

Department of Neurosurgery, King Edward Memorial Hospital and Seth G.S. Medical College, Parel, Mumbai, Maharashtra, India

Date of Web Publication9-Feb-2017

Correspondence Address:
Atul Goel
Department of Neurosurgery, King Edward Memorial Hospital and Seth G.S. Medical College, Parel, Mumbai - 400 012, Maharashtra
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0974-8237.199881

Rights and Permissions

How to cite this article:
Goel A. Is Chiari a “formation” or a “malformation?”. J Craniovert Jun Spine 2017;8:1-2

How to cite this URL:
Goel A. Is Chiari a “formation” or a “malformation?”. J Craniovert Jun Spine [serial online] 2017 [cited 2022 Jan 27];8:1-2. Available from: https://www.jcvjs.com/text.asp?2017/8/1/1/199881

Look deep into nature – you will understand everything better – Einstein

If you can't explain it simply, you don't understand it well enough. – Einstein

Nature has its own incorrigible ways,

Unseen and protective,

Behind a cloak of invisibility!

Unveil the cape,

Therein lays elucidation of all mystery!

In the year 2004, we discussed that a host of soft tissue and bone malformations of the craniocervical junction that includes short neck, torticollis, Klippel–Feil abnormality, assimilation of atlas, C2–C3 fusion, and platybasia are a protective natural response to long-standing atlantoaxial instability.[1],[2] Recently, we introduced the term “short head” and identified that the short head (meaning thereby-short clivus and short vertical height of posterior cranial fossa) and short neck are both simultaneous and proportional.[3],[4] It is now realized that the entire spine length is vertically shortened, and the spinal canal is transversely widened. Essentially, the responsive bone and soft tissue alterations are an attempt by the Nature to reduce the length of the spinal and cranial canal or neural highway designed for the traverse of brainstem and spinal cord. Accordingly, the clivus length/posterior cranial fossa height and neck and spine height are reduced by a variety of bone fusions. We have discussed earlier, the open-close door pattern of movements of bifid posterior arch of atlas on flexion and extension of neck and its role as a natural decompressive laminectomy. The bifid arch of atlas also assists in widening the spinal canal at the level of atlas.[5] Os-odontoideum appears to be a self-bone section designed to avoid injury to the craniocervical cord on neck flexion.

Neural changes include reduction in thickness or atrophy of the spinal cord and brainstem-cerebellum. In addition, there occurs an increase in the length of the neural structures. The angulations of the brainstem and spinal cord change. The net effect is that the longer-thinner brainstem-spinal cord traverses a shorter distance, a process that minimizes the stretch of the indenting odontoid process.

This miracle of nature can be explained by simple physics. It is easier to snap a taut tense rope than a loose one. In a taut cable, the added tension adds stress, which brings the cable closer to breaking point on the application of a small force. In case, the rope is loose the momentum of the same force will get dissipated throughout the cable and will be unable to have enough impact to snap it. The bone fusions provide a stress-free traverse to the cord thus making it “loose” in the spinal canal and able to withstand a lot more injury; then, it would have been able to if it had been taut and draped over the unfused vertebral bodies.

The spinal canal increases in its anteroposterior dimension, despite the reduction of thickness of neural structures. The vertical height of the posterior fossa is reduced, but the anteroposterior dimension increases. The effects of bone fusions and soft tissue alterations make the neck prefer an extension (or hyper-extension) posture, and there is reduction in neck flexion. Platybasia seems to be a process that lifts brainstem superiorly along with the spinal cord. Both the neck and clivus maneuvres are designed to reduce the contact of the junction of brainstem and spinal cord with the tip of the odontoid process. The divine games of the nature that come into play simultaneously to thwart off the potential or manifest dangers related to atlantoaxial instability can only be admired with awe and respect. On the basis of this understanding, it is proposed that these musculoskeletal formations should be labeled as “craniovertebral alterations” and not “craniovertebral anomalies.” An anomaly is a change or a deviation from the norm it is a peculiarity that does not fit in. An alteration is a change that is performed to make a fitting or appearance of an object better. If all the changes seen in the craniovertebral junction are just defending mechanisms brought in by nature to provide sanctity to the neural structures, then wouldn't we be better off calling them “alterations” rather than “anomalies?”

Neural alterations occur that have the same function of protecting the cord from dangers of odontoid process indentation. The tonsillar part of the cerebellum herniates into the spinal canal to provide a protective cushion for the craniocervical cord in an effort to protect the neural structures from getting pinched between the bones.[6],[7] Simultaneously, “water” or “neuroaqua” delivers its motherly protective properties by increasing its presence inside (syringomyelia) and/or outside the spinal cord (external syrinx) and inside (syringobulbia) and/or outside the brainstem and cerebellum (external syringobulbia).[3],[4],[8] Such excessive presence of water has the function of making the neural structures float within an excessive pool of cerebrospinal fluid such that trauma to the neural structures at the tip of the odontoid process is minimized. Simultaneously, there is a reduction in water content within the neural axis that makes spinal cord and brainstem thinner (or atrophied) than its normal girth. The overall impact of the neural alterations is to delay or stall the symptoms related to neural compression. Observation of association of structural malformations with minimum or only marginal clinical symptoms displays the complex and protective orchestra of the creator. To respect the magnificence, it is only appropriate that the term Chiari “malformation” be changed to Chiari “formation.” This will only help in relaying the fact that tonsillar herniation is not an error by the nature but is a divine intervention. Profound poetry should not be undermined by pedestrian prose. It seems that the only anomaly in the craniovertebral junction is atlantoaxial instability. Rest of everything that happens is a response that is protective.

   References Top

Goel A. Treatment of basilar invagination by atlantoaxial joint distraction and direct lateral mass fixation. J Neurosurg Spine 2004;1:281-6.  Back to cited text no. 1
Goel A, Shah A. Reversal of longstanding musculoskeletal changes in basilar invagination after surgical decompression and stabilization. J Neurosurg Spine 2009;10:220-7.  Back to cited text no. 2
Goel A, Nadkarni T, Shah A, Sathe P, Patil M. Radiological evaluation of basilar invagination without obvious atlantoaxial instability (Group B-basilar invagination): An analysis based on a study of 75 patients. World Neurosurg 2016;95:375-82.  Back to cited text no. 3
Goel A, Sathe P, Shah A. Atlantoaxial fixation for basilar invagination without obvious atlantoaxial instability (Group B-basilar invagination): Outcome analysis of 63 surgically treated cases. World Neurosurg 2016. pii: S1878-875031241-4.  Back to cited text no. 4
Goel A, Nadkarni T, Shah A, Ramdasi R, Patni N. Bifid anterior and posterior arches of atlas: Surgical implication and analysis of 70 cases. Neurosurgery 2015;77:296-305.  Back to cited text no. 5
Goel A. Is atlantoaxial instability the cause of Chiari malformation? Outcome analysis of 65 patients treated by atlantoaxial fixation. J Neurosurg Spine 2015;22:116-27.  Back to cited text no. 6
Goel A. Is Chiari malformation nature's protective “air-bag”? Is its presence diagnostic of atlantoaxial instability? J Craniovertebr Junction Spine 2014;5:107-9.  Back to cited text no. 7
Kothari M, Goel A. 'Aqualisation' of neuraxis: Wondrous neuraqua CSF. Neurol India 2008;56:1-3.  Back to cited text no. 8
[PUBMED]  Medknow Journal  

This article has been cited by
1 In Reply to the Letter to the Editor Regarding “Chiari 1 Formation Redefined - Clinical and Radiographic Observations in 388 Surgically Treated Patients”
Atul Goel
World Neurosurgery. 2021; 145: 550
[Pubmed] | [DOI]
2 Retro-Odontoid and Retro-C2 Body Pseudotumor, Pannus, and/or Cyst. A Study Based on Analysis of 63 Cases
Atul Goel, Hardik Darji, Abhidha Shah, Apurva Prasad, Akshay Hawaldar
World Neurosurgery. 2021; 151: e170
[Pubmed] | [DOI]
3 Letter to the Editor Regarding “Chiari Malformation: An Unhelpful Eponym”
Atul Goel
World Neurosurgery. 2021; 156: 164
[Pubmed] | [DOI]
4 Letter to the Editor. Chiari formation
Atul Goel
Journal of Neurosurgery: Pediatrics. 2020; 25(3): 329
[Pubmed] | [DOI]
5 Chiari 1 Formation Redefined–Clinical and Radiographic Observations in 388 Surgically Treated Patients
Atul Goel, Dikpal Jadhav, Abhidha Shah, Survendra Rai, Saswat Dandpat, Ravikiran Vutha, Arjun Dhar, Apurva Prasad
World Neurosurgery. 2020; 141: e921
[Pubmed] | [DOI]
6 Letter to the Editor Regarding “Evaluation of Soft Tissue Hypertrophy at the Retro-Odontoid Space in Patients with Chiari Malformation Type I on Magnetic Resonance Imaging”
Atul Goel
World Neurosurgery. 2020; 144: 326
[Pubmed] | [DOI]
7 In Reply to the Letter to the Editor Regarding “Chiari Formation and Syringomyelia Associated with Hirayama Disease”
Atul Goel
World Neurosurgery. 2020; 144: 340
[Pubmed] | [DOI]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article

 Article Access Statistics
    PDF Downloaded39    
    Comments [Add]    
    Cited by others 7    

Recommend this journal