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Updated: Oct 2, 2026
Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System
Published on: May 12, 2011
Histopathology and ultrastructural examination of optic nerve sheath biopsies after optic nerve sheath decompression
M Taban1, T C Spoor, J G McHenry
1Doheny Eye Institute, USC School of Medicine, Los Angeles, California 90033, USA.
Purpose:
We chose to compare histologically and ultrastructurally changes in the optic nerve sheath after optic nerve sheath decompression, initially after a second surgery and after treatment with mitomycin-C. The mechanism by which optic nerve sheath decompression alleviates papilledema can be further understood in consideration of the results.
Methods:
Tissue was obtained by biopsy from 3 first-time surgical and 4 reoperative cases with and without mitomycin-C in patients with idiopathic intracranial hypertension. The sheaths were fixed in a mixture of 2% paraformaldehyde and 2% glutaraldehyde, osmicated and dehydrated in a series of ethanol, and finally embedded in epon. Tissue blocks were sectioned at 1 microm and stained with both PPD and toluidine blue. Thin sections were examined by transmission electron microscopy.
Results:
Normal meningeal tissue obtained at the time at optic nerve sheath decompression consisted mainly of collagen, closely packed and roughly parallel to the axis of the optic nerve. Collagen deposition seen in scar tissue after secondary optic nerve sheath decompression was extremely disorganized and irregular, with the individual fibers laid down seemingly at random. There was little sense of layering or of parallel arrays. Mitomycin-C appeared to influence collagen deposition in such a way that the collagen was more regularly packed and more closely resembled unoperated tissue.
Conclusions:
The regular well-organized collagen packing seen in normal sheath tissue is disrupted and replaced by less organized but compact scar tissue after optic nerve sheath decompression. With mitomycin use, more regular collagen packing closely approximating that found in unoperated sheath occurs. This configuration of fibers lends support for the filtration mechanism of optic nerve sheath decompression in treating papilledema.
