Retinal detachment as a complication of retrobulbar anesthesia

The authors report an unusual case of retinal detachment after cataract surgery in a 48-year-old man in which it appeared that the retrobulbar needle passed through the sclera and tracked beneath the retina before perforating the retina superior to the disc. The cause of the detachment was not clearly defined until a depigmented line was observed after reattachment of the retina.     

Brain-stem anesthesia as a complication of regional anesthesia for ophthalmic surgery.

Brain-stem anesthesia is a serious complication of orbital regional anesthesia that may occur when the injected local anesthetic agent gains access to the central nervous system by direct spread from the apex of the orbit via submeningeal pathways. In most studies the reported incidence rate during retrobulbar block is one case per 350 to 500 patients. Failure to recognize the condition or to treat it adequately may be life threatening. Treatment includes reassurance, intravenous administration of fluids, pharmacologic circulatory support or suppression of convulsions, and cardiopulmonary resuscitation. With proper treatment complete recovery is the rule. In all situations in which orbital block is to be done, basic cardiopulmonary resuscitation equipment and personnel familiar with its use are essential. Monitoring of the blood pressure, electrocardiography and pulse oximetry should be routine. Having the globe in primary gaze renders the optic nerve less vulnerable, and avoidance of deep penetration of the orbit is of great importance.     

Ocular perforation from a retrobulbar injection

Proliferative vitreoretinopathy occurred in three of seven cases of ocular perforation from retrobulbar injection, resulting in a visual acuity of 20/200 or worse. Direct macular injury and macular pucker occurred in two cases each. Needle injury exit sites were in the posterior pole in all cases. Predisposing factors were not experimentally verified, but associated conditions included axial myopia, multiple injections, traditional superonasal gaze position, previous retinal buckling procedure, and enophthalmos.     

大鼠角膜移植戊巴比妥腹腔注射联用利多卡因球后注射麻醉的效果

目的:探讨大鼠穿透性角膜移植手术戊巴比妥腹腔注射与利多卡因球后注射联合应用的麻醉效果。方法:SPF级雌性SD大鼠158眼行同种异体穿透性角膜移植术,先以戊巴比妥2mL/kgip麻醉,然后向术眼肌锥内注射20g/L利多卡因0.02～0.08mL,观察麻醉效果及并发症。麻醉效果分为满意、比较满意和不满意3级并观察并发症虹膜刺激、晶状体脱失、眼球穿破和眼睑麻痹的发生,作为麻醉效果的辅助指标。结果:因大鼠术中死亡或无法继续观察剔除统计范围7例。在手术成功151例中麻醉效果满意120例(79.5%),比较满意18例(11.9%),不满意13例(8.6%),总体效果满意。戊巴比妥最佳剂量为1.5～2mL/kg;利多卡因球后注射每眼0.03～0.04mL,麻醉时间约60min。有30(19.9%),5(3.3%),9(6.0%)和9(6.0%)例出现虹膜刺激、眼球穿破、眼睑麻痹和晶状体脱失。结论:大鼠穿透性角膜移植术戊巴比妥全身麻醉与利多卡因球后麻醉联合应用效果满意和基本满意,大鼠死亡率低。     

The CT-topography of retrobulbar anesthesia

The anatomic relationship of an injection needle as traditionally placed in retrobulbar anesthesia to optic nerve, orbital vessels and eye muscles is demonstrated by computed tomography.The clinical complications of retrobulbar injections are reviewed and correlated to the orbital topography in different positions of gaze, as analyzed in anatomic sections and CT images.The results indicate that with the traditional technique of retrobulbar injection the most important orbital structures are in the immediate neighbourhood of the needle.A different injection technique is discussed.

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Zusammenfassung Die topographischen Verhältnisse einer mit der üblichen Injektionstechnik plazierten Injektionsnadel zu Sehnerv, Orbitalen Gefäßen und Augenmuskeln werden computer-tomographisch dargestellt.Die klinischen Komplikationen retrobulbärer Injektionen werden in Hinblick auf die orbitale Topographie in verschiedenen Blickrichtungen analysiert. Die Ergebnisse weisen darauf hin, daß bei der traditionellen Injektionstechnik sich die wichtigsten Orbitalen Strukturen in unmittelbarer Nähe der Nadel befinden.Eine andere Injektionstechnik wird diskutiert.

     

Comparison of one-injection-site peribulbar anesthesia and retrobulbar anesthesia

One hundred patients having elective cataract surgery were evaluated in a prospective, randomized, double-blinded study comparing retrobulbar and peribulbar anesthesia. Patients were divided into two study groups and evaluated on three criteria felt to be critical to intraocular surgery. Results showed that the efficacy of the one-injection-site peribulbar block was similar to that of the retrobulbar block for all three criteria. Because the one-injection-site anesthetic is administered outside the muscle cone, the potential for optic nerve and central nervous system complications should be minimized.     

Respiratory arrest following retrobulbar anesthesia

Respiratory arrest is a serious complication of retrobulbar anesthesia. We have prospectively followed 3123 retrobulbar injections to determine the incidence of respiratory arrest and identify possible risk factors. Injections contained either 2% or 4% lidocaine with 0.75% bupivacaine (Marcaine) in a 50:50 mixture by volume (total 10 cc.) to which a 1 ml ampule of hyaluronidase (150 NF units) was added. Use of 4% lidocaine gave a significantly higher incidence of respiratory arrest than 2% lidocaine (0.79% vs. 0.09%; P = 0.003, Fisher's exact test). Serum levels of lidocaine and bupivacaine of patients who arrested were not elevated significantly compared to 20 control patients. All levels were well below accepted levels of toxicity. Thus, 4% lidocaine increases the risk of respiratory arrest. These results suggest the mechanism is not direct intravascular or central nervous system injection.     

Restrictive strabismus after retrobulbar anesthesia

Two rare cases of strabismus resulting from contracture of the extraocular rectus muscles after retrobulbar anesthesia for cataract surgery are described. Clinical signs in both cases suggested that the development of the impaired function of the lateral and superior rectus muscles followed the same pattern: initial stimulation followed by paretic and restrictive stages. Abnormal enlargement of the muscles was identified by computed tomography (CT) and magnetic resonance imaging (MRI). The data indicate that the strabismus was the result of direct injection of anesthetics into the rectus muscle.     

Brain-stem anesthesia complicating retrobulbar block

A previously well 68-year-old man became confused and cyanotic after retrobulbar block for eye surgery. The symptoms resolved within 10 minutes. The author discusses the differential diagnosis of brain-stem anesthesia and proposes recommendations to reduce the incidence of this potentially fatal complication.     

Current concepts in retrobulbar anesthesia

Recently there have been major advances in the field of retrobulbar anesthesia. New agents which allow prolonged anesthesia and akinesia have been introduced. Several new techniques to administer retrobulbar anesthesia have been developed. The toxicity of local anesthetics and the complications arising from such injections have been studied, and ways to avoid and manage them have been expanded.