Perioperative visual loss: what do we know, what can we do?

Abstract

Perioperative visual loss (POVL), a rare, but devastating complication, can follow non-ocular surgery. Highest rates of visual loss are with cardiac and spine surgery. The main causes of visual loss after non-ocular surgery are retinal vascular occlusion and ischaemic optic neuropathy. This review updates readers on the incidence, suspected risk factors, diagnosis, and treatment of POVL due to these conditions. Br J Anaesth 2009; 103 (Suppl. 1): i31-i40Keywords: complications, neurological; complications, neuropathy; eye, intraocular pressure; eye, pupil; surgery, spinal Visual loss after anaesthesia and surgery is a rare, unexpected, and devastating complication. Clinicians have suspected that incidence is increasing, particularly with spinal fusion surgery; however, recent data suggest that this may not be the case. This review will update readers on the incidence, suspected risk factors, diagnosis, and treatment of perioperative visual loss (POVL), in the setting of non-ocular surgery. The causes of POVL are primarily retinal vascular occlusion (RVO) and ischaemic optic neuropathy (ION). The relevant anatomy of the ocular circulation has been reviewed elsewhere and is summarized in Figure 1. 80 Other sources are glycine toxicity during transurethral resection of the prostate, acute angle closure glaucoma, cortical blindness, and expansion of an intraocular sulphur hexafluoride vitrectomy bubble by administration of nitrous oxide. As these are less common, the reader is referred for details to a recent more inclusive review. 80

The Prone Position During Surgery and its Complications: A Systematic Review and Evidence-Based Guidelines

“…31,33,36,37 In particular, it can be due to displacement of plaques from the carotid arteries and can obstruct the central retinal artery. 31 CROA is almost always irreversible.…”

“…50 Roth et al suggests using a square foam headrest and avoiding using a horseshoe head rest during cervical spine surgery, as frequent movement of the head increases risk of position change and increased orbital pressure. 37 Sherman et al used skull traction to suspend the head and reducing direct orbital pressure from the headrest. 47 Frequent monitoring of eye position every 20 minutes with a mirror attachment to the headrest ensures that prolonged inappropriate external orbital pressure is avoided.…”

“…47 Frequent monitoring of eye position every 20 minutes with a mirror attachment to the headrest ensures that prolonged inappropriate external orbital pressure is avoided. 37 Woodruff et al has developed a computer video streaming system to monitor eye position throughout the prone procedure. 51 Trethowan et al suggests using loose endotracheal tube ties, however, care should be taken to not increase risk of endotracheal tube dislodgement.…”

“…31 Colloids along with crystalloids should be used for fluid management as this may theoretically reduce edema as high volumes of crystalloids are avoided. 16,37,48 Changes in perfusion-related medications prior to surgery should be avoided and preoperatively withholding medications that may reduce blood pressure or increase blood coagulability should be taken into consideration. 48 Ophthalmologic evaluation pre-operatively should be considered if the patient has personal or family history of acute angle-closure glaucoma.…”

Perioperative visual loss after spine surgery

“…Additional risk factors include diabetes mellitus, arterial hypotension, arterial hypertension, blood loss, prone positioning during surgery, prolonged surgery, atherosclerosis, sleep apnea, and migraine [13] ; however, it can occur in patients that are otherwise healthy. The pathology is likely a combination of these factors, perhaps together with abnormal autoregulation and other patient specific characteristics that predispose to ischemic injury [23] . Perioperative nonarteritic AION is most often associated with cardiac surgery, especially CABG, and generally presents immediately upon awakening from surgery.…”