SURGERY - Dr. P. THULASI DAS
ENDOSCOPIC SURGERY FOR ORBITAL LESIONS
DECOMPRESSION FOR OPTIC NERVE COMPRESSION
Optic nerve is the second cranial nerve which carries visual
information from the eye ball to the brain. During its course from
the orbit to the brain it is very closedy related to the lateral
wall of the sphenoid sinuses. Using endoscopes this nerve can be
safely approached through the nose. Endoscopic approach is far more
simpler than the previously described approaches. Some times
following head injury, even a trivial one in the region of the
forehead, one may develop sudden blindness, due to fracture
fragments pressing on the optic nerve. Though the impact is on the
forehead, the forces are transmitted to the optic canal area and the
fracture occurs there. Optic canal is a tightly packed compartment
and there is little scope for expansion and any haematoma, oedema or
fracture fragment can produce blindness. This is an emergency which
requires immediate attention, since any delay will result in
permanent blindness. Medical fraternity is not aware of this
condition and many times patients are told “ Nothing can be done”.
It is important to suspect this condition in patient sustaining
injury over the forehead just above the eye, followed by sudden
blindness, especially when the eye ball is normal.
A CT scan should be
ordered, in which a fracture fragment may be demonstrated. Whether
the CT scan shows fractures or not, in the absence of injury to the
eye ball, emergency optic nerve decompression is advised. Emergency
optic nerve decompression done within the first 48 hours carries an
excellent chance of regaining 80-90% of vision. Thereafter the
prognosis declines. Using Endoscopic techniques the optic nerve and
the orbit can be decompressed ever under local anaesthesia with very
little morbidity. Other lesions such as fibrous dysplasias, pneumo
sinus dilantans, mucoceles and tumours can compress the optic nerve.
Endoscopic optic nerve decompression helps in such patients as well.