Cataract surgery is an extremely safe procedure performed countless times without incident, but that doesn't mean surgeons can ignore the importance of limiting the risk of post-op infections. "It's crucial," says ophthalmologist Jeff Boyd, MD, the physician-owner and medical director of Surgical Eye Associates of Delaware in Newark. "Cataracts are low-risk, but you should do all you can to drive infection risks even lower."
In Dr. Boyd's mind, 5% povidone-iodine solution applied to the eye's surface immediately before surgery and an intraoperative injection of intraocular antibiotics are the only definitive ways to reduce the risk of endophthalmitis, an inflammation in the eye that's typically caused by infection.
Intraocular antibiotic injections are a dropless, convenient and cost-effective option for patients. They eliminate the need for pre- and post-op antibiotic drops, and let patients avoid the arduous task of complying with a post-op regimen of 90-plus antibiotic eye drops. It's a marathon treatment that many patients don't complete.
Dr. Boyd decided to go dropless a year ago after reading about the technique on the online forum of the American Society of Cataract and Refractive Surgery. Surgeons touted the method and said it greatly improved the patient experience. He did his homework, reviewed the research and determined it was the best treatment for most of his patients.
After implanting the IOL, Dr. Boyd uses a cannula to inject 0.2 cc of the mixture containing 2 antibiotics inferiorly in the vitreous cavity by a trans-zonular approach. He says some surgeons inject the solution through the scleral, but the trans-zonular approach takes advantage of an already open eye and doesn't subject patients to the potential pain of a needlestick. If he's not using the dropless technique, he injects vancomycin into the eye's anterior chamber.
Dr. Boyd says infection rates are equivalent among patients who apply post-op drops and those who receive intraocular injections. "But by going dropless," he says, "we can save the patient a lot of money and the hassle of doing the drops, which is nice."
That effort to improve patient satisfaction and save them the eye drop regimen's out-of-pocket expense comes at a price. The dropless formulation that Dr. Boyd uses costs $25 per dose, a significant increase to case costs in a specialty with a slim profit margin. Is the additional expense worth it? That depends on a host of factors that leadership at individual facilities must consider. Dr. Boyd knew going dropless would increase his case costs. He was prepared to eat the added expense to improve the post-op experience for his patients and eliminate the possibility of them failing to complete the full drop regimen. "Compliance isn't 100%," he says. "By using intraoperative injections, I see all the medicine go into the eye, and don't have to worry about whether patients will administer all of their drops."
Dr. Boyd hopes a J code for the intraocular injections will eventually be added to cataract coding, allowing reimbursement for the medication. He says some surgeons are getting (ahem) "creative" in trying to get reimbursed, but that's inappropriate and certainly not worth the risk.
Ophthalmologist Neal Shorstein, MD, associate chief of quality at Kaiser Permanente's Diablo Service Area in Northern California, says endophthalmitis is one infection that looms in the mind of every cataract surgeon, even though it's a rare occurrence. Incidence in the United States ranges between 1 in 800 and 1 in 1,200 cases, says Dr. Shorstein, adding that experienced surgeons may never face an infection, or go years without having one occur.
Dr. Shorstein says post-op complications are often identified as the cause of endophthalmitis, and points out that posterior capsular rupture is known to increase the risk. But, he says, "Many surgeries as documented went perfectly well, and yet the patient still developed an infection. There are still mysteries as to why they occur."
Kaiser's large, integrated health system has the ability to track and trend infection rates across 21 ophthalmology centers. In 2007, endophthalmitis rates at Dr. Shorstein's Walnut Creek location were higher than normal. The surgeons and administrators couldn't find a direct cause. They read evidence in the literature about dropless surgery's prophylaxis potential, and since there were no studies that show drops are effective at preventing endophthalmitis, they went dropless to help lower the risk of infection.
The surgeons at Walnut Creek adopted the technique for several months before rolling it out gradually over 5 years. By 2010, they administered intraocular injections to 100% of patients and saw infection rates drop 22-fold. Dr. Shorstein says that's a greater drop than what's reported in the literature because of the higher than normal baseline infection rate in 2007.
The ability of patients in general, and the elderly in particular, to consistently and properly administer eye drops is problematic, says Dr. Shorstein, who adds, "Part of the effectiveness of antibiotic injections has to do with its route, that it's directly administered by the surgeon."
The risk of bioresidue and denatured viscoelastic substance remaining on instruments with small lumens could cause infection if bacteria adhere to the residue that's not killed during the sterilization process, according to Dr. Shorstein. He says the proper flushing and cleaning of instruments before sterilization is an important step in reducing the risk of toxic anterior segment syndrome (TASS), but from a purely epidemiologic standpoint, disposable equipment probably offers the easiest and safest way to avoid potential problems caused by bioresidue that remains on reusable instruments.
"But each surgery center must perform a cost-benefit analysis, to decide which instruments should be reusable and which they should purchase as disposable," he says.
Dr. Shorstein points out that research on TASS and bilateral same-day cataracts performed by ophthalmologists Nick Mamalis, MD, and Steve Arshinoff, MD, FRCSC, respectively, recommend the use of disposables for small-lumened instruments such as I/A tips. Handpieces with larger lumens are easier to rinse to ensure the total washout of residue per manufacturers' recommendations, so it may be less important to go with disposables, according to Dr. Shorstein.
Intraocular antibiotics work in the hours after surgery, but it's also important for the wound to remain sealed when the level of antibiotics in the anterior chamber falls below the minimal inhibitory concentration of the potentially infectious organism, says Dr. Shorstein. He says that's where wound construction and stromal hydration have been shown to increase the stability of the wound. Plus, he adds, leaving the eye at an increased pressure is an effective way to keep the clear corneal flap opposed at the end of surgery.
Dr. Shorstein says cornea sealant has value if there's a posterior capsular rupture. "Although the wound was competent, you want to make sure, given the rupture, that it's well sealed in the hours after surgery," he explains. "Surgeons who might have thrown in a stitch to secure the wound can now use the sealant."
At the end of every case, before he removes the lid speculum, Dr. Boyd thoroughly checks the wound and adds a suture if there is a slight leak, which he says is a rare incident that occurs in less than 1% of cases. He's never used a liquid sealant, but acknowledges that it could seal the wound effectively. Still, he hasn't felt the need to try it because he says it's an expensive option and currently unproven to perform better than a suture.
All 21 centers in Kaiser's Northern California region have adopted antibiotic injections, which have resulted in an endophthalmitis rate between 1 in 7,000 cases and 1 in 10,000 cases. Dr. Shorstein says the health system will publish research in an upcoming issue of the Journal of Ophthalmology that shows a 6% decrease in infection rates over time based on a retrospective review of the centers in Kaiser's northern and southern regions. He explains, "We also think that's because of a greater awareness of the importance of wound construction and management during and after the procedure."