16 Apr Vitrectomy Surgery for Retinal Detachments
Vitrectomy eye surgery for repair of a retinal detachment can be an alternative or adjunct to scleral buckle. Vitrectomy surgery involves the removal of the vitreous from the eye. This procedure was introduced (i.e. invented) in the mid-1970’s and enhanced our ability to treat retinal detachments.
Retinal Tears Cause Retinal Detachments
Remember that the culprit in “rhegmatogenous” retinal detachments is the formation of a hole or retinal tear in the retina. The vitreous can exert “pulling,” or traction, on the retina and cause a retinal tear.
Using a scleral buckle surgery, we introduced “slack” in the vitreous to release some of the traction.
Vitrectomy surgery, too, is focused (no pun intended) on relieving stress in the vitreous. By cutting and removing the vitreous, the vitreous can no longer “pull” on the retina and cause additional tears and keep the detached retina elevated.
Remove the Vitreous, Replace with Gas
After removing the vitreous, the next step usually involves exchanging the vitreous and fluid with intraocular gas. The purpose of the gas is to stop the migration of fluid to the space underneath the retina (by definition, a retinal detachment).
Many people are told (incorrectly) that the purpose of the gas is to “push” the retina back into position, but this is not so. The surface tension of the gas bubble actually acts as a cork, stopping migration of fluid from the vitreous cavity to the subretinal space.
In this way, the retina is reattached, and kept attached, until significant scarring takes place to keep the retina attached by itself.
The gas will absorb, but the length of time required depends upon the type and concentration of the gas (I use 16% SF6, sulfahexafluoride). It does not stay in the eye as long as the gas others use as I believe this to minimize the amount of post-operative complications.
During the time gas is actually in the eye, patients are warned against experiencing large changes in atmospheric pressure. Going to the mountains or airplane travel is usually prohibited as the decreased atmospheric pressure can cause a rapid increase in the volume of the intraocular gas. This could cause the pressure in the eye to increase too fast.
In short, the gas is used as a tool to help reattach the retina. Depending upon the location of the tear in the retina, a patient may be required to keep his/her head in a certain position following surgery. This positioning is as crucial as the operation itself.
For instance, if the tear is located at the top of the eye, the patient may need to sit up in a chair for days following surgery. If the thear is located at the bottom of the retina, face-down positioning may be needed.
Advantages of Vitrectomy
There are a few advantages to vitrectomy for repair of a retinal detachment. There is no worry about becoming more near-sighted as there is no scleral buckle placed. Similarly, there is no chance of causing double vision as there is no manipulation of the eye muscles as in the case of a scleral buckle.
Basically, for the patient, there is less operating outside the eye. Discomfort (“doctor-speak” for pain) is minimized.
There is, however, the chance of infection, as there is with any intraocular surgery, that can lead to blindness. “Endophthalmitis,” the fancy clinical term for this type of infection, is less common in retinal surgery than cataract surgery. The chance of infection occurring is small, somewhere around 1:5,000-10,000.
Vitrectomy with Scleral Buckle
Many times both a scleral buckle and a vitrectomy are utilized for a retinal detachment. There are no clearcut reasons when to use vitrectomy or scleral buckle or both. As I said last post, placing a scleral buckle can be time consuming in certain instances…thus affecting the decision.
What Does This Mean? There are several ways to fix a retinal detachment. Vitrectomy surgery fixes the retinal detachment from the inside, requires less tissue manipulation (i.e. operating) and is more comfortable than a scleral buckle.
Using both modalities, in the right situation, can lead to a higher success rate as we are fixing a retinal detachment from both the inside (vitrectomy) and the outside of the eye (scleral buckle).