Unexpected amaurosis occurring after peribulbar anesthesia: Exploring the causes in two cases

Abstract

Peribulbar anesthesia (PB) is known to be safer than retrobulbar (RB) anesthesia. To our knowledge, no amaurosis has been described after PB. We report here the cases of two patients who underwent PB before membrane peeling. The injections were administered with a 25-gauge, 22-mm bevel disposable needle. The anesthetic used was ropivacaine 1% with a volume of 8 ml and 75 µg of clonidine as an adjuvant (7.5 µg/ml). Given that complete akinesia was not achieved, a second injection of 2 ml was administered in the supero-medial injection site. Thirty minutes after the PB, the first patient experienced amaurosis with no light perception (LP). The ophthalmic examination was normal. Visual acuity recovered after 1 day. Regarding the second patient, the loss of VA was observed 20 min after the PB. IOP was 20 mmHg. The anterior segment and fundus exam were normal. Rubin found the PB technique to be as effective and safer than RB injection, as the needles are not supposed to enter the RB space and Davis and Mandel found no amaurosis after PB. PB is administered via the extraconal injection of an anesthetic agent. These amaurosis might be explained by the fact that some anesthetic may have penetrated the RB space. In cases where two PB injections are administered, the anatomy is expected to change due to the volume effect of the first injection. The second injection is higher risk as it is administered closer to the optic nerve.

Globe penetration during loco-regional anesthesia: prevalence and review of cases

“…This means, in theory, that peribulbar anesthesia carries less risk of inadvertently penetrating vital structures [28][29][30][31] . However, this method has poor efficacy in terms of achieving akinesia after a single injection and the need for a second injection is needed, increasing the risk of ocular complications [7] . Needle penetration of the globe during loco-regional anesthesia is a rare hazard.…”

“…To avoid the necessity for general anesthesia in ocular surgery, blockage of the optic nerve using needle-based blocks is widely implemented to achieve akinesia and analgesia. Complications of the procedure (e.g., haemorrhage [4] , iatrogenic injection of the local anaesthetic into the opticnerve sheath [5] , penetration of the ocular glove [6] , amaurosis [7] , iatrogenic ophthalmic artery occlusion [8][9] or brainstem anaesthesia [10] ) are rare. Although these complications may be avoided with topical administration, loco-regional anesthesia is preferred in procedures requiring both akinesia and deep anesthesia.…”

Reply to re unexpected amaurosis occurring after peribulbar anesthesia: Exploring the causes in two cases

“…We thank Pelligrini et al for their interest regarding our recent article entitled "Unexpected amaurosis occurring after peribulbar anesthesia: Exploring the causes in two cases." 1 The authors reported four cases of amaurosis after peribulbar anesthesia (PB). They proposed an alternative mechanism to this momentary amaurosis: the increase of intraorbital pressure.…”

Reply to: Rezkallah et al. “Unexpected amaurosis occurring after peribulbar anesthesia: Exploring the causes in two cases”

“…We read with interest the paper by Rezkallah et al entitled “Unexpected amaurosis occurring after peribulbar anesthesia: Exploring the causes in two cases.” 1 The Authors report two cases of transient blindness occurred after repeated peribulbar anesthesia (PB). The Authors suppose that “amaurosis might be explained by the fact that some anesthetic may have penetrated the RB (retrobulbar) space.…”