Ophthalmic regional blocks: management, challenges, and solutions

Abstract

In the past decade ophthalmic anesthesia has witnessed a major transformation. The sun has set on the landscape of ophthalmic procedures performed under general anesthesia at in-hospital settings. In its place a new dawn has ushered in the panorama of eye surgeries conducted under regional and topical anesthesia at specialty eye care centers. The impact of the burgeoning geriatric population is that an increasing number of elderly patients will present for eye surgery. In order to accommodate increased patient volumes and simultaneously satisfy administrative initiatives directed at economic frugality, administrators will seek assistance from anesthesia providers in adopting measures that enhance operating room efficiency. The performance of eye blocks in a holding suite meets many of these objectives. Unfortunately, most practicing anesthesiologists resist performing ophthalmic regional blocks because they lack formal training. In future, anesthesiologists will need to block eyes and manage common medical conditions because economic pressures will eliminate routine preoperative testing. This review addresses a variety of topical issues in ophthalmic anesthesia with special emphasis on cannula and needle-based blocks and the new-generation antithrombotic agents. In a constantly evolving arena, the sub-Tenon’s block has gained popularity while the deep angulated intraconal (retrobulbar) block has been largely superseded by the shallower extraconal (peribulbar) approach. Improvements in surgical technique have also impacted anesthetic practice. For example, phacoemulsification techniques facilitate the conduct of cataract surgery under topical anesthesia, and suture-free vitrectomy ports may cause venous air embolism during air/fluid exchange. Hyaluronidase is a useful adjuvant because it promotes local anesthetic diffusion and hastens block onset time but it is allergenic. Ultrasound-guided eye blocks afford real-time visualization of needle position and local anesthetic spread. An advantage of sonic guidance is that it may eliminate the hazard of globe perforation by identifying abnormal anatomy, such as staphyloma.

Complication of Peribulbar Block: Brainstem Anaesthesia

“…Ultrasonografi kullanımı ile göz küresi, optik sinir, anatomik yapılar, iğnenin ilerletildiği yol ve ilacın yayılımı eş zamanlı olarak gösterilerek daha güvenli ve kaliteli blok sağlanabilmektedir (11,12). Bunun yanında ultrasonografi uygulaması daha uzun zaman almaktadır.…”

Local Anaesthesia in Cataract Surgery

“…Sight threatening complications include retro-and peribulbar hemorrhage, ocular penetration and perforation, retinal vascular spasm, optic nerve injury, and ocular myotoxicity [3] . In an audit of 12,000 retrobulbar blocks, Edge and Nicoll [4] found that patients with acquired vascular disease were at a significantly greater risk of periocular bleeding, whereas diabetics presented only a marginal risk of serious hemorrhage.…”

“…Topical anaesthesia was the common practice pattern for cataract surgery among United States Veteran Health Administration [44] and Canadian ophthalmologists [45] . Palte opinioned that with the changing paradiagm of regional blocks, in future Anaesthesiologists will have to perform blocks and in the holding area and Residents would have to become skilled in performing blocks due to larger patient volumes [3] .…”

“…Allergic reactions to HA are a rare but recognized complication of its use such as conjunctival injection with chemosis, periorbital edema, pruritus, pain, and restriction of extraocular muscle motility [3] , orbital inflammatory signs and symptoms [71] , delayed periorbital haemotama and orbital cellulitis [72] delayed orbital inflammation associated with raised intraocular pressure [73] .…”

Dexmedetomidine vs. Magnesium Sulphate as an Adjuvant to Rocuronium Bromide, and Local Anaesthetic Mixture in Peribulbar Anaesthesia for Viteroretinal Surgery

“…Many believe that the peribulbar block is a safer technique however, it has the disadvantage of a slow onset of orbital akinesia and to produce it a larger volume or repeated injections of anesthetic solution is required due to limited diffusion of local anesthetics (LA) [5]. This also increases the frequency of complications such as globe perforation and hemorrhage [4].…”