Perfluorocarbon liquids and Silicone oils

28 October, 16

During the Masters of Surgery session “Winds of Innovation” at the 2016 AAO Retina Subspecialty Day the use of Perfluorocarbon liquids and Silicone oils were highlighted as still very important surgical tools for successful VR-surgery. The lectures about these products you can find in the program book "Retina 2016 Winds of Innovations, Chicago Oct. 14-15".

Use of Perfluorocarbon Liquids by Stanley Chang MD (Section I: Masters of Surgery page 4)

Perfluorocarbon liquids (PFCLs) are a versatile tool during vitreoretinal surgery for complex forms of retinal detachment. This video will cover several intraoperative scenarios where PFCL can be  helpful and potential complications can be minimized when PFCLs are properly used. The following maneuvers will be demonstrated:

  1. Peeling the internal limiting membrane (ILM) for a case of retinal detachment secondary to macular hole in a highly myopic eye with PFCL assistance

  2. Flattening the retinal detachment with proliferative vitreoretinopathy (PVR) and posterior retinal breaks

  3. Using PFCL to protect the retina during retrieval of a dislocated IOL, phacofragmentation of a dislocated dense cataract, and removal of intruded Miragel implants

Retinal detachment with macular hole in a highly myopic eye should be managed first with the use of intravitreal triamcinolone to highlight any layers of adherent cortical vitreous (vitreoschisis). Following removal of the adherent vitreous, the retinal detachment is flattened by a fluid–air exchange, with internal drainage of subretinal fluid through the macular hole. This should be done slowly so that the macular hole does not enlarge. The ILM must be removed so that the macular hole can be closed, reducing the potential for recurrent retinal detachment. Under air, brilliant blue dye is injected to stain the ILM. After removal of the dye, fluid is reintroduced into the vitreous and ILM peeling is initiated. If the retina is too mobile, the subretinal fluid is aspirated through the macular hole and PFCL is injected to immobilize the retina. The edge of ILM can then be identified, and ILM can be gently peeled under PFCL using a tangential peeling force. The PFCL is then removed, and a fluid–air exchange can be done for the gas tamponade. Posterior retinal breaks are often encountered in reoperations of eyes with retinal detachments and PVR. All posterior epiretinal membranes are peeled from the retina before using PFCL first. Membranes should be carefully dissected so that existing breaks are not enlarged and minimal new breaks develop. The second step will be to reduce any anterior PVR forces that are causing retinal foreshortening by debulking the peripheral anterior vitreous. Then a small amount of PFCL is injected within the funnel of the detachment, to test how well the retina flattens. If the retinal breaks flatten, PFCL injection is continued. If the retina anterior to the PFCL bubble remains elevated, it may be necessary to release the anterior tractional forces by making a relaxing retinotomy. Once the retinal breaks are flattened under PFCL, it may be possible to free any curled edges of the retinal breaks. PFCLs are occasionally helpful in the management of dislocated IOL or dense nuclear lens fragments. With IOLS the PFCL is used to elevate the edge of the capsular bag or IOL so that it can be more safely grasped with forceps and brought anteriorly. If the lens falls back, the macula is protected by the PFCL. PFCL can be added to stabilize the eye volume if a corneal incision is necessary to remove and IOL. PFCL can also be used to protect the macula during fragmentation of dense brunescent cataract fragments. We have also used PFCL during removal of fragment of a Miragel scleral buckle that has gradually swollen and intruded into the vitreous over time.

Selected Readings

  1. Chang S, Kwun RC. Perfluorocarbon liquids in vitreoretinal surgery. In: Ryan S, ed. Retina, 4th ed. St. Louis: Elsevier (Mosby); 2006: ch 128, pp 2179-2190.
  2. Dalma-Weiszhausz J, Franco-Cardenas V, Dalma A. A modified technique for extracting dislocated lenses with perfluorocarbon liquids and viscoelastics. Ophthalmic Surg Lasers Imaging 2006; 41:572-574.

 

Optimal Use of Silicone oil by Grazia Pertile MD (Section I: Masters of Surgery page 5)

Indications

Silicone oil should be used when a long-term tamponade is required but cannot be provided by long-acting gas. In particular, in cases of:

  • Initially closed retinal break that is expected to reopen, usually due to proliferative vitreoretinopathy (PVR)

  • Chorioretinal traumatic lesions, especially when positioned posterior to the equator and therefore at high risk of PVR

  • Inferior large retinotomies that are at risk of dehiscence due to vitreous base contraction or PVR

  • Diabetic patients with severe proliferative retinopathy or anterior proliferation at high risk of recurrent vitreous hemorrhage

  • Patients who cannot position

Injection Techniques

The aim is to reach an almost complete filling of the vitreous cavity with silicone oil. In order to remove virtually all the fluid, two techniques can be used:

  1. First perform an air exchange, and then inject silicone oil. The major disadvantages of the temporary use of air are the risk of slippage of the retina, in cases of large retinotomies, and weakening of lens-zonules that can facilitate the passage of oil in the anterior chamber during the postoperative period.

  2. Inject perfluorocarbon liquid (PFCL) up to the level of the sclerotomies, and then inject oil, while aspirating the meniscus of fluid remaining between oil and PFCL.

In the past, it was demonstrated that silicone oil does not fit into small recesses, such as those adjacent to indentation caused by scleral buckling. Take into consideration the removal of (part) of the buckling material that can interfere with the tamponade.

Preventable Complications

  • If possible, maintain a separation between anterior and posterior segment to prevent silicone oil from coming into contact with the cornea. For this reason, it is preferable to perform a phacoemulsification and IOL implantation, rather than lensectomy alone.
  • Avoid temporary increase of the IOP during oil injection to prevent migration of silicone oil into the anterior chamber through an area of zonulolysis.
  • In aphakic eyes, perform a peripheral iridectomy at the 6 o’clock position to enable the aqueous to pass from the posterior to the anterior chamber, when the silicone oil occludes the pupil.

Unpreventable Complications

  • Increase of the IOP in absence of overfilling
  • Migration of silicone oil into the anterior chamber, in cases of severe hypotony

http://www.aao.org/Assets/5121b4c7-c0a1-45ec-af71-6dc145c1431d/636114389241630000/retina-2016-syllabus-pdf?inline=1