Vitreoretinal surgery continues to be an exciting field of medicine as new techniques and instrumentation are frequently being developed. While many advances have improved efficacy and safety, it is important to recognize that complications of vitreoretinal surgery continue to exist.
A thorough literature review has highlighted three primary issues that retinal surgeons must be prepared for. These complications include hemorrhage, infection, and retinal detachment.
The purpose of this review is to educate eyecare providers on these aforementioned complications and to discuss factors that influence patient susceptibility.
3 major complications in vitreoretinal surgery
Vitreoretinal surgery complication 1: Intraocular & periocular hemorrhage
Intraocular or periocular hemorrhage is a complication that vitreoretinal surgeons must be prepared for. Hemorrhage can result from several sources, and precautions must be taken at each critical point of surgery.
Retrobulbar hemorrhage, a serious and vision-threatening complication, may occur during the administration of the retrobulbar or peribulbar block.
Retrobulbar hemorrhage
Although rare, retrobulbar hemorrhage can lead to rapid and permanent vision loss and must be readily recognized by the surgeon. Clinical manifestations of retrobulbar hemorrhage include proptosis, pain, rapid orbit swelling, conjunctival swelling, ecchymosis, and elevated intraocular pressure (IOP).1
A case report published in 2016 described a patient taking prasugrel blood thinners with a pre-operative vision of 20/40 succumbing to retrobulbar hemorrhage following retrobulbar block anesthesia. The visual acuity consequently led to no light perception (NLP) vision, and the delayed complication of optic nerve atrophy was observed during the patient’s one-month post-operative evaluation.2
Retrobulbar hemorrhage risk factors
Inappropriate depth of needle insertion is one potential risk factor for retrobulbar hemorrhage.3 The authors advised that the retrobulbar needle be inserted no more than 2.5cm and to not inject the anesthetic against resistance, as this could indicate the needle has come in contact with an extraocular muscle. Longer needle length has also been identified as a risk factor for retrobulbar hemorrhage or optic nerve injury.
One study showed that needle lengths of 31.75mm (1.25in) are associated with better outcomes, while lengths as much as 38.1mm (1.5in) may increase the risk for optic nerve trauma.4 A second study had similar findings, reporting that needle lengths of 40mm should never be fully inserted into the orbit and that needle lengths of 35mm should still be used with caution.5
With any injection around the orbit, there comes a risk of inadvertently penetrating the globe. Globe penetration is defined as a single-entry wound, whereas globe perforation has both entry and exit wounds. In severe cases, penetration may even be associated with globe explosion due to significantly elevated IOP as the anesthetic is injected into the eye.6
Puncturing the globe can also result in intraocular hemorrhage. Depending on the pathology being treated, bleeding in the vitreous cavity, subretinal, or suprachoroidal space may make a challenging case even more difficult.
Intraocular hemorrhage following vitrectomy and scleral buckle
While hemorrhage resulting from vitrectomy and scleral buckle are both rare, it is still important to discuss the inherent risks of hemorrhage associated with both procedures. With vitrectomy, the literature highlights several important risk factors with a high likelihood of predisposing patients to bleeding.
These include high myopia, scleral buckling during pars plan vitrectomy (PPV), rhegmatogenous retinal detachment, history of previous retinal detachment surgery, intra-operative systemic hypertension, and even patient movement during the procedure.7
When discussing scleral buckles, complications resulting in hemorrhage are often extremely rare, and from the data that is available, patient outcomes tend to improve following corrective surgery.8
Considerations for intraocular hemorrhage and systemic anticoagulation therapy
Many patients requiring retina surgery may concurrently take anticoagulant therapy for other systemic diseases.
Blood thinners may include, but are not limited to:
- Clopidogrel (Plavix)
- Coumadin (Warfarin)
- Rivaroxaban (Xarelto)
- Edoxaban (Savaysa)
- Apixaban (Eliquis)
- Dabigatran (Pradaxa)
- Prasugrel (Effient)
- Ticagrelor (Brilinta)
Given the nature of potentially devastating bleeding during surgery, it is necessary to discuss the risks versus benefits of suspending blood thinners before surgery. The consensus on whether to hold off on blood thinners before surgery remains somewhat controversial. Some surgeons believe it is not necessary to suspend anticoagulant therapy.
Studies the risk of intraocular hemorrhage from vitreoretinal surgery in patients on anticoagulation therapy
Oh et al. conducted research intervals in 1994, 2004, and 2008 on 822 patients who underwent vitreoretinal surgery. Their review was retrospective for 1994 and 2004 but contemporaneous for 2008.
Of 822 patients, 214 were on antiplatelet or anticoagulant therapy without any variation in regimens. The study ultimately found no statistically significant difference in the incidence of intraocular bleeding in patients on blood thinners versus those without.
Of their patients who did not suspend blood thinners and experienced intraocular hemorrhage, they found that the bleeding was minor and self-limited. The authors ultimately recommend holding blood thinners when possible to reduce the risk of hemorrhagic complications. However, whether or not the risks outweigh the benefits should be taken on a case-by-case basis.9
A similar study by Meillon et al. reviewed 804 vitreoretinal surgeries performed on patients taking antiplatelet or anticoagulant medications.10 Among participants, 148 were taking antiplatelets, 63 were taking anticoagulants, and 18 were being treated with direct oral anticoagulants.
After univariate analysis, anticoagulant agents were not associated with hemorrhagic complications, and following multivariate analysis, neither were antiplatelet medications. The authors also note that all hemorrhagic complications that did occur resolved spontaneously, and no thromboembolic events were reported in the month following surgery.
Lastly, a systematic review conducted by Confalonieri et al. analyzed 22 articles describing peri-operative and post-operative outcomes in patients on antiplatelet or anticoagulation.11 The authors support the continuation of blood thinners before, during, and after vitreoretinal surgery, finding reduced rates of cardioembolic events.
Vitreoretinal surgery complication 2: Endophthalmitis
When performing vitreoretinal surgery (and intravitreal injections), the possibility of introducing microbial pathogens to the eye must be carefully accounted for. While signs of infection may take several days to develop, the complication is considered a universal ophthalmic emergency, and quick recognition and action is necessary to prevent further damage to the eye.12
While rare, endophthalmitis following vitrectomy surgery can lead to devastating vision loss even with prompt treatment. Signs and symptoms include pain, decreased vision, hypopyon, and dense vitritis. The reported incidence ranges between 0.03% and 0.14% for large gauge (20g) vitrectomy.
Studies on the incidence of endophthalmitis after vitreoretinal surgery
One meta-analysis of 31 studies reported a statistically significant higher incidence of endophthalmitis in microincision or sutureless vitrectomy with 25g (0.11%) versus 20g PPV (0.03%).
However, advances in retina surgery (e.g., valved cannulas, shorter operating times, etc.) may eventually skew these numbers in favor of more modern small gauge techniques. Predisposing risk factors include inadequate wound closure, hypotony, vitreous incarceration at a sclerotomy site, and absence of tamponading agent.13
Endophthalmitis has been extensively studied in the clinical setting across multiple countries. One retrospective study conducted at the Aravind Eye Hospital in India found an endophthalmitis rate of approximately 1 out of 3,761 cases. Both 23- and 25-gauge needles were used for surgery, and a total of 26,332 vitrectomies had been performed.
Out of 26,332 surgeries, only seven patients developed endophthalmitis. The study also reported endophthalmitis rates for patients who underwent intravitreal injections, and rates were nearly double that of minimal interface vitrectomies (1 in 1,857 cases). Risk factors for infection ranged from the geographical region where the patients resided to chronic conditions such as diabetes.14
Vitreoretinal surgery complication 3: Retinal detachment (RD)
A third complication of vitreoretinal surgery that eyecare providers must be prepared for is retinal detachment (RD). One retrospective study in France analyzed the incidence rates of RD for patients who underwent repair for either idiopathic macular hole (MH) or epiretinal membrane (ERM).
Out of 272 MH repairs, 18 patients suffered post-operative RDs. Out of 362 surgeries for ERM, only 9 patients suffered post-operative RD. The rate for RD following MH repair was approximately 6.6%, while the rate following ERM repair was 2.5%.
The authors suggest that the nature of MH surgery, such as substantial depression necessary to induce posterior vitreous detachment during surgery, as well as intraocular gas tamponade, led to increased rates of post-surgical RD in the MH group over the ERM group. The authors did not find that chronic conditions, such as diabetes, or anatomical variations, such as axial length, played a significant role in post-surgical RD rates.15
Another retrospective study conducted in Germany found that of 904 eyes that received elective vitreoretinal surgery, subsequent retinal detachments occurred in 17 eyes (1.88%).16 The mean time from elective surgery to the second corrective surgery was 248 days, ranging between 3 and 1,837 days.
One retrospective study found that of 13,625 eyes that underwent cataract surgery, approximately 10 required further surgery to correct macular-hole-related RD. In the same study, it was found that 7 of these 10 eyes were significant for high myopia.17
It should be noted that for these patients, the average time from surgery to the onset of RD was approximately 38.5 months, with some patients developing symptoms as early as 9 months. Therefore, while it is an unlikely acute outcome following vitreoretinal surgery, it should be considered as a delayed complication, and frequent monitoring is necessary to determine progression.
Conclusions
In this article, we underscore bleeding, infection, and retinal detachment as three common complications, eyecare providers must be mindful that:
- For bleeding, surgical techniques and clinical manifestations were highlighted, along with the influence that anticoagulant therapies have on intra-operative bleeding.
- Infection was addressed in regard to PPV and intravitreal injections.
- Finally, as with all vitreoretinal surgeries, the possibility of subsequent retinal detachment was discussed, with studies showing that everything from prior surgeries to patient-specific anatomical variants can play a role in post-surgical onset.
Though vitreoretinal surgery has advanced tremendously over recent decades, complications still occur. Therefore, residents and fellows need to recognize possible complications of vitreoretinal surgery and what factors influence patient outcomes to optimize surgical results.
