INTRODUCTION
Traumatic optic neuropathy (TON) can occur along any level of the optic
nerve and results in partial to complete loss of visual acuity. TON can
be classified into direct and indirect subtypes. Direct TON results from
fractures involving the orbit or optic canal such as those associated
with projectiles, facial smashes, or iatrogenic during endoscopic sinus
surgery. Conversely, forces transmitted at different levels to the optic
nerve after blunt head trauma can cause indirect TON. The damage to the
optic nerve is hypothesized to be secondary to intraneural edema,
hematoma, shearing of nerve fibers, altered cerebrospinal fluid
circulation, and impaired retroaxonal transport of brain-derived growth
factors1-3. It occurs in about 2.5% of midface
fractures and 10% of craniofacial fractures 4-5. For
decades, treatment of compressive optic nerve neuropathy was
conservative, with intravenous application of high dose corticoids, and
in later years in combination with nerve growth
factors6,7 . Surgical treatment for traumatic optic
neuropathy was not routinely done in the past as a minimally invasive
approach to the optic nerve was not available; also the available
intracranial or pterional approaches could add to the morbidity of the
patient. However with advent of endoscopic sinus surgeries, a new
corridor for optic nerve decompression started to open up. The treatment
of TON is controversial; primarily because of absence of a standard
treatment protocol- medical as well as surgical. Secondly spontaneous
improvement of vision in patients with TON has been reported in 20–38
% of untreated cases 8, 9. The aim of EOND is to
decompress the bony optic nerve canal along with removal of bony
fragments with or without impingement on the optic nerve as well as
reducing the intracanalicular pressure by added fenestration of nerve
sheath in selected patients ; expecting restoration of nerve function.
High dose corticosteroids administered systemically have a similar
effect, resulting in a “medical decompression”. The aim of this study
is to assess the role of timing of surgery and pre operative visual
status in the prognosis of direct TON undergoing EOND. Current
literature lacks a proper grading system for evaluating post operative
visual improvement. Hence, we have even developed a quantitative
assessment for improvement of vision following EOND.
MATERIALS AND METHODS
During the last 10 years we had 31 patients with traumatic optic
neuropathy – direct type; of which one patient had bilateral direct
type traumatic optic neuropathy. So totally we had operated on 32 eyes.
All the patients in this study were males.