Anatomy of the eye orbit:-
The orbit is the name given to the socket which accommodates the eye and other associated structure like the optic nerve, blood vessels, the lacrimal gland, cheek ligaments etc. The orbit is shaped like a pear, with the apex being positioned posterior and the base being located anteriorly. The orbit is formed by seven bones joining together. The orbit is connected to various planes anteriorly, laterally and medially. It is connected on a medial plane to the ethmoidal and the sphenoidal sinuses on their anterior planes. The medial margin of the orbit constitutes of the maxilla as well as the lacrimal and the frontal bones. The medial wall is very thin with is main component i.e. the orbital plate of ethmoid being papyraceous. The point of meeting of the medial wall with the roof is where both the anterior as well posterior ethmoidal foramina transmit the arteries and the nerves of the same name. The anterior and posterior ethmoid arteries pass through the anterior and posterior ethmoid foramina in the medial wall. They act as prominent surgical landmarks. The alignment of the orbit is such that the medial walls are parallel and the lateral walls are perpendicular.
Need for medial orbitotomy:-
Medial orbitotomy is done for orbital decompression in various diseases like the Grave’s disease. Medial orbitotomy is also performed to remove orbital tumors which are located mainly on the medial side of the optic nerve or to fix fractures of the medial orbit and the naso-ethmoidal complex.
The Grave’s disease which was originally called the Graves-Basedow disease was initially described as the combination of Hyperthyroidism, exophthalmos and goiter. It is not a very uncommon disease and typically occurs between 30-50 years of age. Males have a higher rate of developing severe Grave’s disease. Only 5-6% of people develop severe problems which require orbital decompression to restore proper functioning of the eye. Almost 50% of the patients with this disease develop ophthalmopathy which can cause severe corneal problems that may call for decompression. Grave’s disease may cause decrease in ocular motility, diplopia, poor cosmesis and optic neuropathy.
A physical examination of the eyes and the surrounding structures is done. A CT scan or an MRI is also done in order to prepare for the surgery by assessing the position and thickness of various orbital structures.
The primary goal of medial orbitotomy is to open up the eye socket and the medial part of the orbit to accommodate the eye better and to remove the tumors or treat the fractures.
Orbital decompression is carried out by removing the bones that typically make up the orbit. Less intensive decompression can be carried out by removing intraconal and extraconal fat. This type of decompression in combination with bone removal can be used for more comprehensive decompression. New surgical techniques now allow surgeons to endoscopically decompress the orbit. The medial wall can be approached endoscopically but a balanced method which requires repositioning of lower lid in conjunction with lateral decompression is often used.
The surgical approach for obtaining decompression involves uses of endoscopes which involve inferior and medial walls. The approach taken is dependent upon the anatomy of the patient and the level of decompression which is to be done. If the patient is undergoing the orbitotomy for cosmetic reasons, a combination of medial wall and inferior wall decompression in combination with lateral orbitotomy may be used.
Medial wall decompression in which the medial strut is preserved between the ethmoid cavity and the inferior wall and which is balanced with the procedure of lateral decompression may be done, especially if the patient is undergoing the procedure for cosmetic reasons.
How to prepare for the procedure:-
A full ophthalmologic check up of the patient is done. The appearance of the cornea and conjunctiva, extra ocular motility, visual acuity, visual fields and symptoms of diplopia are recorded. A preoperative CT scan (coronal and axial) of the orbits and the sinuses is also done. The procedure is done under general anesthesia.
Precautions after the procedure:-
The patient is advised not to blow the nose post the procedure. The follow up checks are done every one to two weeks to ensure proper healing.
Complications and risks:-
The endoscopic method can cause the following complications:-
- Nasolacrimal duct obstruction
- Inflammation caused by suture
- Swelling and bruising
One of the rare complications of the procedure includes injury to the optic nerve but it is unlikely with good endoscope control. Another rare complication includes leakage of cerebrospinal fluid.
By removing medial orbitotomy, the eye may be moved back in the socket in a better position. This also decreases the pressure within the eye, which improves the problem of double vision and blurry vision. The risk of corneal infection is also reduced. Orbitotomy is a minimally invasive procedure which should be performed by expert orbital surgeons only in a reputed medical facility.
Dr. Debraj Shome is one of the leading Oculoplastic surgeons in India. He holds numerous accolades in his name and is currently practicing in Mumbai, India.
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