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NI FEATURE: THE EDITORIAL DEBATE I-- PROS AND CONS
Year : 2018  |  Volume : 66  |  Issue : 4  |  Page : 947-948

Review of controversies or a ‘controversial review’ on the surgical management of congenital craniovertebral junction anomalies


Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Date of Web Publication18-Jul-2018

Correspondence Address:
Dr. Pravin Salunke
Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0028-3886.236988

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How to cite this article:
Salunke P. Review of controversies or a ‘controversial review’ on the surgical management of congenital craniovertebral junction anomalies. Neurol India 2018;66:947-8

How to cite this URL:
Salunke P. Review of controversies or a ‘controversial review’ on the surgical management of congenital craniovertebral junction anomalies. Neurol India [serial online] 2018 [cited 2018 Aug 17];66:947-8. Available from: http://www.neurologyindia.com/text.asp?2018/66/4/947/236988




In the manuscript 'Controversies in the surgical management of congenital craniocervical junction disorders – a critical review,' it is of concern that the real controversies in the field of CVJ surgery have been missed in the pursuit of a particular surgical technique. It is important to give a balanced perspective while writing this review that specially focuses on the Asian subcontinent. The following commentary attempts to broach on the majority of the underlying controversies in the subject.

Concept of basilar invagination and atlanto-axial dislocation: Conventionally static or dynamic?: It has been observed that patients with congenital AAD and BI have oblique cervical (C) 1-2 joints. This probably causes progressive slipping of C1 over C2.[1] The plane of dislocation depends on the plane of obliquity of facets. Traditionally, basilar invagination occurs when the dens is violating the foramen magnum. However, in true BI, the basal structures like the occipital condyles, should be medially deviated and the relationship between C1 and C2 should not be altered in the vertical plane. The so called BI possibly is invagination or vertical dislocation of C2 within C1 (assimilated or intact).[2]

Recent indices and multiplanar atlantoaxial dislocation (AAD): The traditionally described indices used plain radiographs. In the current era, the bony anatomy is studied on computed tomographic (CT) scans. The C1-2 has six degrees of freedom of movements. Rotation and translation is possible in axial, sagittal and coronal planes. Hence, the dislocation can occur in any of these planes (antero-posterior [AP], vertical, lateral translation, lateral angular and rotational, and is not merely bi-planar [AP and vertical]). The objective measurement of C1-2 dislocation in each plane has been described.[3] The obliquity of C1-2 joints can be assessed using different references.[3]

Transoral decompression or joint manipulation: Though many surgeons have shifted to joint manipulation, a significant subset still prefers transoral decompression. The result of transoral decompression of odontoid (TOD) and posterior fusion in experienced hands are as good as that seen in the technique of joint manipulation. Endoscopic TOD provides a better view and control while drilling the dens.[4] There are complex cases with craniovertebral junction anomalies with rotational component wherein many surgeons would prefer to still perform TOD. The dens can be decompressed through a endoscopic assisted transcervical route.[5]

Joint manipulation: Anterior vs posterior: The dislocation can be reduced by manipulating the C1-2 facets. Though the posterior approach is common, the joints can be approached anteriorly either through a trans-cervical incision [6] or the transoral route (TARP).[7]

Facetal drilling: While the comprehensive drilling the facets until the joint surfaces has attained a flat disposition in both sagittal and coronal planes irrespective of the severity of obliquity is a useful technique,[8] Chandra et al., prefer to utilize it in a selected subset of patients with moderately oblique joints. Dr. Goel on the other hand, drills the joint surface only to release the joints. In fact, drilling may not be a very good idea in young children with oblique joints.

Use of spacers: The use of spacers in the C1-2 joint space is controversial. The spacers may act as jammers or may be used to compensate for the bone drilled. However, some surgeons fear the occurrence of settling and redislocation with spacers. The graft window in spacers is limited and may hamper bony fusion.

Manoeuvres to re-align C1-2 vertebrae: There are many techniques to realign C1-2 and the distraction compression, extension and reduction (DCER) technique is just one of them.[9],[10],[11] Unfortunately, the DCER focuses only on vertical and antero-posterior realignment (biplanar) and cannot correct lateral angular, lateral translation or rotational dislocation (multiplanar). Goel insinuates an osteotome in the joint space and turns it to distract the joint. Using C2 isthmus as the fulcrum and the osteotome as a lever, the joint is manipulated.[12] Further, as the Goel's plate (a dynamic compression plate) is tightened, it realigns the joint completely. Similarly, a loosely fastened rod can be held with a long rod holder and manipulated with one of the tulips of facetal screws as a fulcrum to achieve the desirable multiplanar realignment (in the AP, lateral, vertical and axial rotational planes).[11]

Foramen magnum decompression: In the presence of Chiari malformation, many surgeons add foramen magnum decompression (FMD) with posterior fusion.[13] Some even add it in the absence of Chiari malformation, especially with severe dislocation, to avoid neural compromise during manipulation. Goel on the other hand does not prefer FMD even with Chiari malformation.[14]

Short segment C1-2 facetal fusion or long segment occipito-cervical (OC) fusion: The inclusion of occipital squama in the construct may not be necessary, irrespective of the presence of assimilated or intact C1.[15] From the point of view of the range of motion, it does not make any difference in the cases with an assimilated arch. However, the OC fusion requires inclusion of multiple levels in the construct to avoid the Cantilever effect. This significantly hampers the neck movements and adversely affects the quality of life. Furthermore, it may create a crankshaft effect in growing children.[16] Short segment C1-2 facetal fusion on the other hand is surgically challenging in order to achieve an adequate fusion in complex anomalies and the risks involved while performing the procedure may outweigh the benefits.

Challenges with anatomic aberrations: Anomalous vertebral artery/pseudofacets: It is important to recognize these anomalies preoperatively. An anomalous vertebral artery may be a major cause of concern to many surgeons, often mandating a change of plan from a C1-2 fusion to an O-C2 fusion without joint manipulation. However, with experience, the artery can be mobilised and is not a deterrent to C1-2 joint drilling and manipulation.[17]

The presence of pseudofacets can confuse a surgeon not conversant with these anomalies. Drilling of these pseudofacets may cause bone loss and decrease the screw purchase.[18] These pseudofacets could be used to the surgeon's advantage to manipulate the C1-2 joints. However, due to their rarity, the long term result of manipulating the pseudojoints in such cases is not known.

Each technique has its own merits and demerits. With time and experience, each can be personalised and mastered upon, and the benefits accrued would outweigh the risks. No matter what the technique is, the outcome of patients is prime.



 
  References Top

1.
Salunke P, Sharma M, Sodhi HB, Mukherjee KK, Khandelwal NK. Congenital atlantoaxial dislocation: A dynamic process and role of facets in irreducibility. J Neurosurg Spine. 2011;15:678-85.  Back to cited text no. 1
    
2.
Jain VK. Atlantoaxial dislocation. Neurol India 2012;60:9-17.  Back to cited text no. 2
[PUBMED]  [Full text]  
3.
Salunke P, Sahoo SK, Deepak AN, Khandelwal NK. Redefining congenital atlantoaxial dislocation: Objective assessment in each plane before and after operation. World Neurosurg. 2016;95:156-64.  Back to cited text no. 3
    
4.
Yadav YR, Madhariya SN, Parihar VS, Namdev H, Bhatele PR. Endoscopic transoral excision of odontoid process in irreducible atlantoaxial dislocation: Our experience of 34 patients. J Neurol Surg A Cent Eur Neurosurg 2013;74:162-7.  Back to cited text no. 4
    
5.
Yadav YR, Ratre S, Parhihar V, Dubey A, Dubey NM. Endoscopic technique for single-stage anterior decompression and anterior fusion by transcervical approach in atlantoaxial dislocation. Neurol India 2017;65:341-7.  Back to cited text no. 5
[PUBMED]  [Full text]  
6.
Patkar S. Anterior facetal realignment and distraction for atlanto-axial subluxation with basilar invagination. A technical note. Neurol Res 2016;38:748-50.  Back to cited text no. 6
    
7.
Yin QS, Li XS, Bai ZH, Mai XH, Xia H, Wu ZH, et al. An 11-year review of the TARP procedure in the treatment of atlantoaxial dislocation. Spine (Phila Pa 1976) 2016;41:E1151-8.  Back to cited text no. 7
    
8.
Salunke P, Sahoo SK, Deepak AN, Ghuman MS, Khandelwal NK. Comprehensive drilling of the C1-2 facets to achieve direct posterior reduction in irreducible atlantoaxial dislocation. J Neurosurg Spine. 2015;23:294-302.  Back to cited text no. 8
    
9.
Suh BG, Padua MR, Riew KD, Kim HJ, Chang BS, Lee CK, et al. A new technique for reduction of atlantoaxial subluxation using a simple tool during posterior segmental screw fixation: Clinical article. J Neurosurg Spine 2013;19:160-6.  Back to cited text no. 9
    
10.
Yin YH, Qiao GY, Yu XG, Tong HY, Zhang YZ. Posterior realignment of irreducible atlantoaxial dislocation with C1-C2 screw and rod system: A technique of direct reduction and fixation. Spine J 2013;13:1864-71.  Back to cited text no. 10
    
11.
Salunke P, Sahoo S, Khandelwal NK, Ghuman MS. Technique for direct posterior reduction in irreducible atlantoaxial dislocation: Multi-planar realignment of C1-2. Clin Neurol Neurosurg 2015;131:47-53.  Back to cited text no. 11
    
12.
Goel A, Shah A. Atlantoaxial facet locking: Treatment by facet manipulation and fixation. Experience in 14 cases. J Neurosurg Spine 2011;14:3-9.  Back to cited text no. 12
    
13.
Sindgikar P, Das KK, Sardhara J, Bhaisora KS, Srivastava AK, Mehrotra A, et al. Craniovertebral junction anomalies: When is resurgery required? Neurol India 2016;64:1220-32.  Back to cited text no. 13
[PUBMED]  [Full text]  
14.
Goel A, Gore S, Shah A, Dharurkar P, Vutha R, Patil A. Atlantoaxial fixation for Chiari 1 formation in pediatric age-group patients: Report of treatment in 33 patients. World Neurosurg 2018;111:e668-e677.  Back to cited text no. 14
    
15.
Salunke P, Sahoo SK, Sood S, Mukherjee KK, Gupta SK. Focusing on the delayed complications of fusing occipital squama to cervical spine for stabilization of congenital atlantoaxial dislocation and basilar invagination. Clin Neurol Neurosurg 2016;145:19-27.  Back to cited text no. 15
    
16.
Salunke P, Karthigeyan M, Sahoo SK, Sunil N. Improvise, adapt and overcome-challenges in management of pediatric congenital atlantoaxial dislocation. Clin Neurol Neurosurg 2018;171:85-94.  Back to cited text no. 16
    
17.
Salunke P, Sahoo S, Deepak AN. Anomalous vertebral artery is not a deterrent to C1-2 joint dissection and manipulation for congenital atlantoaxial dislocation. Neurol India 2015;63:1009-12.  Back to cited text no. 17
[PUBMED]  [Full text]  
18.
Salunke P, Futane S, Sharma M, Sahoo S, Kovilapu U, Khandelwal NK. 'Pseudofacets' or 'supernumerary facets' in congenital atlanto-axial dislocation: Boon or bane? Eur Spine J 2015;24:80-7.  Back to cited text no. 18
    




 

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