Take-home message: A new instrument can be used during cataract surgery to remove silicone oil placed in the vitreous cavity during prior surgery for complicated retinal detachment.
Reviewed by Lawrence R. Goldberg, MD
Saint Petersburg, FL—Using a new instrument (Goldberg Silicone Oil Extractor, Rhein Medical), cataract surgeons can perform a one-stage procedure for cataract extraction, IOL implantation, and silicone oil removal.
This is contrasted with a two-stage procedure of first having the retinal surgeon extract the silicone oil, and at a future date, having the cataract surgeon remove the cataract and implant the IOL.
The two-stage procedure is less desirable since it requires two separate operating room sessions, is more costly, and lengthens the visual rehabilitation of the patient, said Lawrence R. Goldberg, MD, an ophthalmologist in private practice in Saint Petersburg, FL, who designed the tool in collaboration with Rhein Medical.
The instrument is a reusable cannula designed to both stent open the temporal cataract wound to allow egress of the silicone oil out of the eye and aspirate any residual oil that remains in the vitreous cavity. Dr. Goldberg said.
A significant oil bubble remains in about 1/3 of cases, resistant to removal by irrigation through the sideport incision, ultimately requiring controlled aspiration utilizing the new cannula.
In the one-stage surgical procedure, after cataract removal and posterior capsulorhexis, a 23-gauge anterior chamber maintainer is inserted through the sideport incision, and in the majority of cases the oil is removed after it floats on top of the balanced salt solution (BSS) and out the stented temporal wound.
In some patients, a substantial oil bubble remains in the posterior chamber that will not float through the posterior capsulorhexis and out the main incision regardless of the patient's head position. These are the cases for which the new cannula is especially beneficial.
To extract resistant oil bubbles, the cannula is inserted down through the posterior capsulorhexis, near or just peripheral to the viewed edge of the pupil (depending on the bubble's position). Then the downward facing port is slightly embedded into the oil bubble's surface, occluding its opening.
Next, the anterior chamber maintainer's tubing is kinked to stop irrigation into the eye; sideport irrigation will push the oil bubble into the periphery, out of view.
Lastly, full aspiration is engaged, which will slowly diminish and totally remove the remaining oil bubble. Complete removal of the oil may take 15 to 20 minutes. Viscoelastic is then placed in the capsular bag, followed by posterior chamber IOL implantation.
“It is noteworthy to mention that stopping irrigation into the eye by kinking the tubing of the chamber maintainer will not cause collapse of the anterior chamber as long as the port of the cannula is in continuous contact with the oil bubble, since the aspirated oil occludes the lumen, sealing it, so that only oil is removed, leaving the balanced salt solution in the eye,” Dr. Goldberg said.
He added that it is advisable to “prime” the cannula and tubing with oil when initially using the cannula to stent the wound open by placing the port into the main body of oil through the posterior capsulorhexis and aspirating until it is all removed from the eye or a residual oil bubble is noted.
During the procedure, any time oil is being aspirated it is normal to hear the machine's warning sound signifying a clogged line.
“This just means the oil is moving very slowly; the warning should be ignored and full aspiration mode should be continued,” Dr. Goldberg said.
Impetus for design creation
He began thinking about designing an instrument for removing silicone oil several years ago, having experienced difficulty in a case where a residual oil bubble could not be fully removed despite moving the patient's head into a dependent position.
At that time, the only available aids discussed in the literature or demonstrated in videos were using a short, sharp 19-gauge needle to stent the wound open or placing an irrigating anterior chamber maintainer through the sideport incision.
During one of Dr. Goldberg’s cases involving an oil bubble resistant to removal, he found an old angled irrigating instrument with a port opening that was angled down and connected it to the aspiration tubing. Although it sucked out the oil bubble, the instrument had a small lumen, causing the oil removal to be very slow.
He concluded that a similar instrument with a larger lumen might be more effective at extracting oil. He and the team at Rhein Medical then developed such an instrument, which was launched last fall.
In many cases where silicone oil has been placed in the vitreous cavity to repair a complicated retinal detachment, tiny bubbles of emulsified oil travel around the zonules and end up in dependent positions of the anterior chamber. They can be observed layered at the top of the anterior chamber when the patient is examined at the slit lamp.
During cataract surgery on a supine patient, the oil is layered up against the central corneal endothelium, blocking the view of anterior chamber details, so its removal is required. Initially, anterior chamber oil removal is accomplished by making a sideport incision and irrigating out as much oil as possible using a regular 27-gauge angled cannula connected to a syringe with BSS.
If any oil bubbles remain, they can be cleared from the anterior chamber by injecting viscoelastic through the sideport incision prior to performing the anterior capsulorhexis.
During the cataract surgery portion of the procedure (routine phacoemulsification), Dr. Goldberg recommends a 3-3.5 mm temporal clear corneal incision depending on the size of the IOL planned (6 or 6.5 mm), which will allow the oil to more readily flow out around the silicone oil extractor cannula as it stents the wound open.
Dr. Goldberg routinely makes a 5-mm anterior capsulorhexis opening.
“I strongly recommend that during posterior capsulorhexis, the anterior chamber should not be overfilled with viscoelastic, and the capsular bag should not be inflated at all, leaving the anterior and posterior capsule leaflets in contact,” Dr. Goldberg said.
When initiating the posterior capsular tear, oil that bulges forward will be held back by the viscoelastic. He prefers making a 3.5-4 mm posterior capsulorhexis opening so he can implant his regular 6-mm, one-piece posterior chamber IOL in the bag. If the posterior capsulorhexis is larger than 4 mm, then a three-piece 6.5 mm posterior chamber IOL is preferred.
Lawrence R. Goldberg, MD
Dr. Goldberg developed the Silicone Oil Extractor in coordination with Rhein Medical.