Surgical removal of intraocular silicone oil

The article was professionally consulted with Specialist Doctor I Nguyen Thi Bich Nhi - Ophthalmologist - General Surgery Department - Vinmec Nha Trang International General Hospital.

Intraocular silicone oil removal is performed by surgical removal of the silicone oil from the vitrectomy eye along with intraocular oil injection to treat retinal detachment to avoid possible oil-related complications. silicon.

Silicone oil has been used medicinally since the 1950s in breast plastic surgery. And by 1962, silicone oil was used in retinal surgery. And studies that have also reported success rates in post-surgery revascularization are approved using silicone oil as a vitreous substitute.
Silicone oil belongs to a mixture of monomer and polymeric organic silicon, resistant to high temperatures when sterilized by autoclave. Although silicone oil is biologically inert, it can induce mild body reactions while providing a good cover. The primary role of the commonly used silicone oil is to enable long-term retinal compression.
The main mechanism of action of silicone oil is to create a buoyant force on the retina due to its own weight. However, since the surface tension between oil and water is significantly less than the surface tension between air and water, which is significantly smaller than the surface tension between air and water, this force is only one third of the force generated. by air bubbles, which are sufficient to keep the retina pressurized if the contractile release is good but not enough to counteract the muscle forces that directly pull on the retina.
In addition, there are several mechanisms by which intraocular silicone oil may prevent retinal detachment. The presence of silicone oil balls located close to the retinal surface can change the direction of the traction forces thereby making them parallel to the retina and correspondingly less effective than direct traction. When there is a large oil ball in the vitreous cavity, only a thin layer of vitreous will remain covering the surface of the posterior retina. It is possible that under these conditions the amount of fluid in the eyeball is insufficient to cause retinal detachment unless there is significant traction.

Treatment of endophthalmitis with vitrectomy and intraocular oil injection is not only limited to the inflammatory process, limiting the damage of ocular components, but silicone oil also helps prevent and limit retinal detachment. For cases of endophthalmitis that respond well to medical treatment at an early stage, when the retina has not yet been damaged, the postoperative outcome is usually very good. Patients with a severe inflammatory process that respond poorly to medical treatment, have retinal detachment, or a retina that is severely damaged by the inflammatory process, the surgical process is difficult, and it is difficult to remove all blindness. However, in this case, after removing the vitreous, conducting gas exchange and intraocular silicone oil injection, the majority of postoperative progress progressed in a beneficial direction, the inflammatory process decreased rapidly. In some cases, there was thick secretion in the pupil area, in some cases, fundusoscopy showed a localized pus-filled mass below and persisted for a long time after applying surgery.
Many studies have demonstrated that total vitrectomy in patients with endophthalmitis not only completely eliminates vitreous infection, but can also prevent the formation of intraocular prolapse. vitreous chamber. Inject silicone oil at the end of vitrectomy to reduce the risk of retinopathy and eliminate potential postoperative tears. The vitreous chamber is filled with silicone oil, which is invulnerable to bacteria so there should be no problem of re-infection at this stage. Creating a transparent optical environment after the silicone oil injection process allows the restoration of visual function. Silicone oil also prevents the occurrence of hypoglycaemia in the postoperative period.

Complications associated with the use of silicone oil can occur during surgery, in the postoperative period, or even after removal of the intraocular silicone oil. Retrospective clinical and histopathological studies of the eye showed that silicone oil vacuoles, free or attached to macrophages, were observed in all retinal layers. Silicone oil vacuoles are seen in the optic nerve, choroid, retinal pigment epithelium, corneal stroma, iris and ciliary stroma, anterior and posterior membranes of the retina. Silicone oil infiltration can be seen in early intraocular tissue. The presence of silicone oil vacuoles in the optic nerve is associated with intraocular pressure and may increase intraocular pressure causing optic nerve damage. Therefore, early surgical removal of silicone oil should be considered. Because, studies have shown that the focal regions of silicone oil in the retina are involved in retinal structural disorders, where the retinal tissue or preretinal oil is ablated, the dispersion of macrophages is closely related to the dispersion with silicone oil.

Patients who are indicated to perform intraocular silicone oil removal surgery include those who have had vitrectomy surgery, intraocular silicone oil pump, good pressure retina. Or subjects with signs of complications of intraocular silicone oil such as corneal degeneration, keratosis pilaris, glaucoma. However, in some cases, patients are not indicated to perform this method, including inflammatory diseases in the eyes or systemic diseases that do not allow surgery.
The surgeon will perform this procedure with the vitreous cutter and attached tools.
Before the surgery, the patient is given an eye exam to indicate the removal of the intraocular oil along with a full body examination. Patients are also thoroughly explained about the surgical process as well as possible complications after surgery
4.1. Technique for performing intraocular silicone oil removal First, the doctor will apply an eye antiseptic with 5% betadin solution, fix the eyelids with the rim, and open the conjunctiva close to the margin. Use the compass to measure and open the eyeball 3 way through Pars plana. Continue to fix the infusion line. Then place an intraocular light or an intraocular camera, re-check the patient's retinal condition and treat possible retinal damage. The doctor will open the line, aspirate the main ball of oil through the scleral opening using a syringe or vitrectomy suction system. Tiny oil bubbles were washed away by spontaneous infusion of fluid through the incision in the sclera or repeated gas exchange. Next, the doctor will re-check the condition of the retina, additionally cut vitreous, remove the proliferative membrane or intraocular laser. Then, close the openings into the eyeball and inject a combination antibiotic to fight inflammation of the paraocular or subconjunctiva.
4.2. Monitoring and managing complications after surgery The doctor will use strong antibiotics and anti-inflammatory locally as well as the whole body after surgery. Continue to examine the patient's eyes daily for early detection and management of complications such as hemorrhage, infection, recurrent retinal detachment, glaucoma.
Some complications may occur after surgical removal of intraocular silicone oil such as ocular atrophy, recurrence of vitreous prolapse, recurrence of retinal detachment, uveitis, endophthalmitis.