Atormac
Neurology India
menu-bar5 Open access journal indexed with Index Medicus
  Users online: 564  
 Home | Login 
About Editorial board Articlesmenu-bullet NSI Publicationsmenu-bullet Search Instructions Online Submission Subscribe Videos Etcetera Contact
  Navigate Here 
 Search
 
  
 Resource Links
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Article in PDF (435 KB)
    Citation Manager
    Access Statistics
    Reader Comments
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this Article
   References

 Article Access Statistics
    Viewed148    
    Printed3    
    Emailed0    
    PDF Downloaded9    
    Comments [Add]    

Recommend this journal

 


 
Table of Contents    
COMMENTARY
Year : 2020  |  Volume : 68  |  Issue : 1  |  Page : 61-62

Nasal Endoscopic Trans‑Sphenoidal Optic Nerve Sheath Fenestration for Intractable Intracranial Hypertension with Papilloedema–Optimism with Caution


Department of Otorhinolaryngology and Head and Neck Surgery, All India Institute of Medical Sciences, New Delhi, India

Date of Web Publication28-Feb-2020

Correspondence Address:
Dr. Alok Thakar
Department of Otorhinolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, New Delhi - 110 029
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0028-3886.279661

Rights and Permissions



How to cite this article:
Thakar A, Aggarwal K. Nasal Endoscopic Trans‑Sphenoidal Optic Nerve Sheath Fenestration for Intractable Intracranial Hypertension with Papilloedema–Optimism with Caution. Neurol India 2020;68:61-2

How to cite this URL:
Thakar A, Aggarwal K. Nasal Endoscopic Trans‑Sphenoidal Optic Nerve Sheath Fenestration for Intractable Intracranial Hypertension with Papilloedema–Optimism with Caution. Neurol India [serial online] 2020 [cited 2020 Mar 28];68:61-2. Available from: http://www.neurologyindia.com/text.asp?2020/68/1/61/279661




A sizeable percentage of patients with idiopathic intracranial hypertension (IIH) experience papilledema and debilitating visual loss. Medical management is not always successful, and surgical management by the traditional CSF diversion/shunting procedures is plagued with high rates of shunt blockage requiring revision procedures. Venous sinus stenting and optic nerve sheath fenestration are alternative interventions but are again associated with significant complication and revision rates. This issue reports the experience of Srivastava AK et al.,[1] with the surgical alternative of nasal endoscopic trans-sphenoidal optic nerve sheath fenestration as an action of last resort ('pis aller') for patients with refractory IIH.

A large body of experience exists for optic nerve sheath fenestration (ONSF) undertaken at the intra-orbital segment.[2],[3] Fenestration of the nerve sheath allows for egress of CSF, leading to release of the increased pressure at the optic nerve head and consequent relief of papilloedema, visual loss, and headache. A unilateral ONSF is known to result in bilateral improvement and indicates the operation being essentially a CSF drainage procedure. It is also hypothesized that subsequent repair and glial proliferation may cordon off the distal optic nerve sheath from the proximal and so protect it from the increased ICP, but this seems unlikely as it would not explain the bilateral improvement noted.

The intra-orbital ONSF may be undertaken by many approaches but is mainly undertaken by the medial transconjunctival approach. The medial rectus is incised at its insertion, and the globe rotated to access the optic nerve. Complication rates of 4.8–45% have been noted with diplopia and ciliary ganglion denervation (pupil and accommodation denervation) being the most distressing.[3] The high complication rate and also the difficulty of surgical access have led to the proposal of accessing the optic nerve not at the intra-orbital segment, but the more accessible intracanalicular segment on the lateral wall of the sphenoid.

Tarrat et al.[4] in a systematic review in 2017, noted six reports totalling 34 patients treated for IIH by the trans-sphenoidal optic nerve sheath fenestration. 30/34 patients had a unilateral operation but nevertheless noted improvements bilaterally. Papilloedema, visual fields, visual acuity, and headache were all improved in > 80% of patients. Curiously, two reports (11 patients) noted of improvements despite the operation being restricted to a bony decompression of the bony canal and no sheath incision. No complications were noted in any of the six reports. The present report has undertaken a bilateral trans-sphenoidal optic nerve sheath fenestration in nine patients with similar rates of improvement, and no medium-term complications.

There is however one essential difference between an ONSF undertaken in the intra-orbital segment with the CSF egress into the sterile intra-orbital contents, versus ONSF in the canalicular segment with potential contamination from the sphenoid and nasal environment. The present report notes of 1/9 patients developing a postoperative CSF leak necessitating a temporary lumbar drain, and also notes in passing that all patients had minor CSF leaks and 'postnasal drip' for the first 2–3 PO days. Spontaneous and recurrent CSF leaks are well documented as complications of IIH, and creating a deliberate CSF fistula in the sphenoid is likely to further augment such risks. The literature citing the safety of optic nerve sheath incision relates to the post-traumatic optic nerve decompression scenario,[5] and cannot be safely extrapolated to the situation with increased ICP. These insights do indicate that though the small experience with trans-sphenoidal ONSF to date does note of promising resolution rates, caution is advised with regard to the potential for persistent CSF leak and possible meningitis.



 
  References Top

1.
Srivastava AK, Singh S, Khatri D, Jaiswal AK, Sankar R, Paliwal VK, et al. Endoscopic endonasal optic nerve decompression with durotomy: Pis aller in the mind of a blind. Neurol India 2020;68:54-60.  Back to cited text no. 1
  [Full text]  
2.
Scherman DB, Dmytriw AA, Nguyen GT, Nguyen NT, Tchantchaleishvili N, Maingard J, et al. Shunting, optic nerve sheath fenestration and dural venous stenting for medically refractory idiopathic intracranial hypertension: Systematic review and meta-analysis. Ann Eye Sci 2018;3:26.  Back to cited text no. 2
    
3.
Nithyanandam S, Manayath GJ, Battu RR. Optic nerve sheath decompression for visual loss in intracranial hypertension: Report from a tertiary care center in South India. Indian J Ophthalmol 2008;56:115-20.  Back to cited text no. 3
[PUBMED]  [Full text]  
4.
Tarrats L, Hernández G, Busquets JM, Portela JC, Serrano LA, González-Sepúlveda L, et al. Outcomes of endoscopic optic nerve decompression in patients with idiopathic intracranial hypertension. Int Forum Allergy Rhinol 2017;7:615-23.  Back to cited text no. 4
    
5.
Thaker A, Tandon DA, Mahapatra AK. Surgery for optic nerve injury- Should nerve sheath incision supplement osseous decompression? Skull Base 2009:19:263-71.  Back to cited text no. 5
    




 

Top
Print this article  Email this article
   
Online since 20th March '04
Published by Wolters Kluwer - Medknow