Unilateral visual loss after cervical spine surgery

This is a case report of a patient who underwent an uneventful surgery for atlanto-axial dislocation in the prone position, after which he developed painless, unilateral loss of vision in the immediate postoperative period. Based on the ophthalmologic findings a probable diagnosis of ischemic optic neuropathy (ION) was made. Although he recovered his visual acuity completely in 1 month, the visual field defects and color vision abnormalities persisted. Intraoperative anemia, hypotension, with or without vasculopathic risk factors, and prolonged surgery in the prone position have been reported as major risk factors for the development of this complication following spine surgery. However, this healthy young man had an uneventful surgery with no such intraoperative complications. ION in this patient could have been due to a combination of factors, such as a malpositioned horseshoe headrest and surgery performed in the prone position, both of which have the potential to raise the intraocular pressure and lower the perfusion pressure of the optic nerve/nerve head. Variations in the blood supply of the optic nerve due to the presence of watershed zones could be another explanation for this dreaded complication.     

Perioperative visual loss after spine surgery

Perioperative visual loss(POVL) is an uncommon, but devastating complication that remains primarily associated with spine and cardiac surgery. The incidence and mechanisms of visual loss after surgery remain difficult to determine. According to the American Society of Anesthesiologists Postoperative Visual Loss Registry, the most common causes of POVL in spine procedures are the two different forms of ischemic optic neuropathy: anterior ischemic optic neuropathy and posterior ischemic optic neuropathy, accounting for 89% of the cases. Retinal ischemia, cortical blindness, and posterior reversible encephalopathy are also observed, but in a small minority of cases. A recent multicenter case control study has identified risk factors associated with ischemic optic neuropathy for patients undergoing prone spinal fusion surgery. These include obesity, male sex, Wilson frame use, longer anesthetic duration, greater estimated blood loss, and decreased percent colloid administration. These risk factors are thought to contribute to the elevation of venous pressure and interstitial edema, resulting in damage to the optic nerve by compression of the vessels that feed the optic nerve, venous infarction or direct mechanical compression. This review will expand on these findings as well as the recently updated American Society of Anesthesiologists practice advisory on POVL. There are no effectivetreatment options for POVL and the diagnosis is often irreversible, so efforts must focus on prevention and risk factor modification. The role of crystalloids versus colloids and the use of α-2 agonists to decrease intraocular pressure during prone spine surgery will also be discussed as a potential preventative strategy.     

Postoperative visual loss associated with spine surgery

Postoperative visual loss associated with spine surgery is a rare complication with no established definitive etiology. Multiple case reports have been published in the literature, and an overview of the case reports of the various visual disturbances following spine surgery is presented. Our objective was to review the current literature and determine if there were any risk factors that suggest what kind of patients have a higher likelihood of developing postoperative visual loss. Furthermore, analysis of factors common to the cases may offer a better understanding of possible etiologies leading to prevention strategies of postoperative visual loss. We used PubMed to perform a search of literature with spine surgery cases that are associated with visual disturbances. A total of 7 studies representing 102 cases were reviewed and evaluated in regard to age, sex, comorbidities, diagnosis, operative time, blood loss, systolic blood pressure, lowest hematocrit, and visual deficits and improvement. Ischemic optic neuropathy, especially posterior ischemic optic neuropathy, was the most common diagnosis found in the studies. The average age of the patients ranged from 46.5 years to 53.3 years with the majority having at least one comorbidity. Operative time ranged on average from 385 min to 410 min with a median in one case series of 480 min, average blood loss ranged from 3.5 l to 4.3 l and no visual improvement was seen in the majority of the cases. The etiology of postoperative visual loss is probably multifactorial, however, patients with a large amount of blood loss producing hypotension and anemia along with prolonged operative times may be causing a greater risk in developing visual disturbances. An acute anemic state may have an additive or synergistic effect with other factors (medical comorbidities) leading to visual disturbances. Although our study failed to provide definitive causative factors of postoperative visual loss, suggestions are made that warrant further studies.     

Positioning patients for spine surgery: Avoiding uncommon position-related complications

Positioning patients for spine surgery is pivotal for optimal operating conditions and operative-site exposure. During spine surgery, patients are placed in positions that are not physiologic and may lead to complications. Perioperative peripheral nerve injury (PPNI) and postoperative visual loss (POVL) are rare complications related to patient positioning during spine surgery that result in significant patient disability and functional loss. PPNI is usually due to stretch or compression of the peripheral nerve. PPNI may present as a brachial plexus injury or as an isolated injury of single nerve, most commonly the ulnar nerve. Understanding the etiology, mechanism and pattern of injury with each type of nerve injury is important for the prevention of PPNI. Intraoperative neuromonitoring has been used to detect peripheral nerve conduction abnormalities indicating peripheral nerve stress under general anesthesia and to guide modification of the upper extremity position to prevent PPNI. POVL usually results in permanent visual loss. Most cases are associated with prolonged spine procedures in the prone position under general anesthesia. The most common causes of POVL after spine surgery are ischemic optic neuropathy and central retinal artery occlusion. Posterior ischemic optic neuropathy is the most common cause of POVL after spine surgery. It is important for spine surgeons to be aware of POVL and to participate in safe, collaborative perioperative care of spine patients. Proper education of perioperative staff, combined with clear communication and collaboration while positioning patients in the operating room is the best and safest approach. The prevention of uncommon complications of spine surgery depends primarily on identifying high-risk patients, proper positioning and optimal intraoperative management of physiological parameters. Modification of risk factors extrinsic to the patient may help reduce the incidence of PPNI and POVL.     

Perioperative risk factors for posterior ischemic optic neuropathy

Background:

Infarction of the optic nerve posterior to the lamina cribrosa, called posterior ischemic optic neuropathy (PION), is a condition that can result in profound bilateral blindness. Cases of PION treated at this institution and those described in the literature were analyzed to identify clinical features that profile those individuals at risk of PION in an attempt to identify major contributing factors that could be addressed prophylactically to enable effective prevention.

Study Design:

Salient clinical features in seven cases of PION diagnosed at the Doheny Eye Institute between 1989 and 1998 are compared with 46 cases of PION reported in the literature.

Results:

In the Doheny series there were six men and one woman aged 12 to 66 years (mean, 47 years). Five patients were status-post spine surgery, one was status-post knee surgery, and one had a bleeding stomach ulcer. Vision loss was simultaneously bilateral in six of seven patients (85.7%) and was apparent immediately after surgery. There were no abnormal retinal or choroidal findings including diabetic retinopathy, in any of the patients. Notable contributing factors were blood loss in all seven patients, ranging from 2,000 to 16,000 mL, with a drop in hematocrit of 9.5% to 19% (mean, 14%), and intraoperative systemic hypotension in all patients. Facial edema was a factor in three of six spine surgery patients (50%). Patients reported in the literature had a mean age of 50 years and were also predominantly men (34 of 46, 74%) who underwent spine surgery (30 of 46, 65.2%).

Conclusions:

Middle-aged men undergoing spine surgery with prolonged intraoperative hypotension and postoperative anemia and facial swelling are at risk of developing PION from hypovolemic hypotension. Avoiding or immediately correcting these contributory factors can reduce the incidence of PION.     

The American Society of Anesthesiologists Postoperative Visual Loss Registry: analysis of 93 spine surgery cases with postoperative visual loss

BACKGROUND: Postoperative visual loss after prone spine surgery is increasingly reported in association with ischemic optic neuropathy, but its etiology is unknown. METHODS: To describe the clinical characteristics of these patients, the authors analyzed a retrospectively collected series of 93 spine surgery cases voluntarily submitted to the American Society of Anesthesiologists Postoperative Visual Loss Registry on standardized data forms. RESULTS: Ischemic optic neuropathy was associated with 83 of 93 spine surgery cases. The mean age of the patients was 50 +/- 14 yr, and most patients were relatively healthy. Mayfield pins supported the head in 16 of 83 cases. The mean anesthetic duration was 9.8 +/- 3.1 h, and the median estimated blood loss was 2.0 l (range, 0.1-25 l). Bilateral disease was present in 55 patients, with complete visual loss in the affected eye(s) in 47. Ischemic optic neuropathy cases had significantly higher anesthetic duration, blood loss, percentage of patients in Mayfield pins, and percentage of patients with bilateral disease compared with the remaining 10 cases of visual loss diagnosed with central retinal artery occlusion (P < 0.05), suggesting they are of different etiology. CONCLUSIONS: Ischemic optic neuropathy was the most common cause of visual loss after spine surgery in the Registry, and most patients were relatively healthy. Blood loss of 1,000 ml or greater or anesthetic duration of 6 h or longer was present in 96% of these cases. For patients undergoing lengthy spine surgery in the prone position, the risk of visual loss should be considered in the preoperative discussion with patients.     

Phosphodiesterase type 5 inhibitors,visual changes,and nonarteritic anterior ischemic optic neuropathy: Is there a link?

Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common acute optic neuropathy and one of the most common causes of sudden vision loss in the elderly. Recently, NAION has been associated with the use of phosphodiesterase type 5 inhibitors (PDE5i) in men with erectile dysfunction (ED). A causal relationship could not be established given the large number of men safely using PDE5i and the limited number of NAION cases reported in these men. ED and NAION share common risk factors; therefore, some men with ED should be expected to develop NAION. However, sudden vision loss or decreased vision in one or both eyes demands immediate cessation of PDE5i use and urgent patient assessment. No causal relationship between PDE5i and the development of NAION exists for the moment, yet physicians should be aware of a possible adverse reaction and inform patients accordingly.     

The American Society of Anesthesiologists Postoperative Visual Loss Registry: Analysis of 93 Spine Surgery Cases with Postoperative Visual Loss

Background: Postoperative visual loss after prone spine surgery is increasingly reported in association with ischemic optic neuropathy, but its etiology is unknown.

Methods: To describe the clinical characteristics of these patients, the authors analyzed a retrospectively collected series of 93 spine surgery cases voluntarily submitted to the American Society of Anesthesiologists Postoperative Visual Loss Registry on standardized data forms.

Results: Ischemic optic neuropathy was associated with 83 of 93 spine surgery cases. The mean age of the patients was 50 +/- 14 yr, and most patients were relatively healthy. Mayfield pins supported the head in 16 of 83 cases. The mean anesthetic duration was 9.8 +/- 3.1 h, and the median estimated blood loss was 2.0 l (range, 0.1-25 l). Bilateral disease was present in 55 patients, with complete visual loss in the affected eye(s) in 47. Ischemic optic neuropathy cases had significantly higher anesthetic duration, blood loss, percentage of patients in Mayfield pins, and percentage of patients with bilateral disease compared with the remaining 10 cases of visual loss diagnosed with central retinal artery occlusion (P < 0.05), suggesting they are of different etiology.     

Effect of the degree of reverse Trendelenburg position on intraocular pressure during prone spine surgery: a randomized controlled trial

Background contextPostoperative vision loss complicates an estimated 1 in 1,100 prone spine surgical cases. This complication has been attributed to ischemic optic neuropathy, with one proposed reason being perioperative elevations in intraocular pressure (IOP). Previous research has studied the effects of table inclination on IOP in awake volunteers; however, the effects in spine surgery patients have not been investigated for reverse Trendelenburg positioning using a prospective, randomized controlled study design.PurposeTo assess the effect of table inclination on IOP in patients undergoing prone spine surgery.Study designSingle-center, prospective randomized controlled study.Patient sampleNineteen patients with no history of eye pathology, undergoing prone spine surgery at Dwight D. Eisenhower Army Medical Center, were randomly assigned to a table position: neutral, 5°, or 10° of reverse Trendelenburg.Outcome measuresIntraocular pressure, mean arterial pressure (MAP), estimated blood loss, fluid resuscitation, and ophthalmologic complication were assessed before and after induction and at incremental times during surgery, beginning at 30 minutes, 60 minutes, and 60-minute increments thereafter.MethodsMultivariate analyses evaluated surgical time, IOP, MAP, estimated blood loss, and fluid resuscitation as a function of table inclination to determine the effect of patient positioning on identified risk factors for postoperative vision loss.ResultsSurgical times ranged from 33 to 325 minutes. A rapid increase in IOP was noted after prone positioning, with continued increases as time elapsed. The neutral group exhibited statistically higher IOP compared with the 5° reverse Trendelenburg group after 60 minutes and the 10° group through 60 minutes of surgery. The trend continued through 120 minutes; however, because of a lack of power, we were unable to determine the statistical significance. There were no statistically significant differences between the 5° and 10° reverse Trendelenburg groups.ConclusionsReverse Trendelenburg positioning elicits decreased IOP compared with prone positioning for surgery times less than 120 minutes. Ten degrees of reverse Trendelenburg attenuate the rise in IOP during prone spine surgery superiorly in comparison with 5°. No significant complications were associated with reverse Trendelenburg positioning.     

Anterior ischemic optic neuropathy and dialysis: role of hypotension and anemia.

The pathogenesis of anterior ischemic optic neuropathy (AION) primarily involves interference with the posterior ciliary artery blood supply to the prelaminar optic nerve. Uremic patients often have coexisting pathology such as hypotension (decreased blood delivery), or hypertension, atherosclerosis (increased resistance to blood supply), and anemia (low blood oxygen carrying capacity), predisposing them to AION. We describe a 49-year-old patient on dialysis for many years. He had long-standing hypotension, worsened during each dialysis treatment. He awoke one morning at age 48 complaining of blurred vision in the left inferior field. Based on the clinical course, funduscopic and fluorangiographic examination and visual field defects, AION was diagnosed. Nine months after the loss of vision in the left eye, vision in the right eye became blurred and worsened over the next 24 hours. The diagnosis of AION in the right eye was made. At the last examination ten months later, the patient, still amaurotic, was given a very poor prognosis for further recovery of the visual defects. Surprisingly, very few cases of AION have been reported in chronic uremic patients on dialysis: to the best of our knowledge, only 12 including ours. Most of these cases share some features, including hypotension above all and anemia as common risk factors. Neither the type of dialysis treatment (hemo-, peritoneal dialysis) nor sex seem to have any influence on the occurrence of AION. Uremic children can be affected. What is striking in the three published pediatric cases is that they all had polycystic kidney disease. Treatment of AION in all 12 cases consisted of a combination of steroids, i.v. saline, blood transfusions and rhEpo. AION was more frequently bilateral and irreversible, ending in permanent amaurosis. In conclusion, this study aims to stress that most cases of AION occurring in chronic uremic patients on dialysis have some common features, including hypotension above all and anemia as common risk factors.     

Visual impairment after laparoscopic donor nephrectomy

Loss of vision after surgery is rare and has never been reported after a laparoscopic procedure. We describe a case of visual deficits secondary to posterior ischemic optic neuropathy after a laparoscopic donor nephrectomy. The potential etiologies of postoperative visual loss are reviewed, and recommendations for avoiding this complication are discussed.     

Erblindung nach nichtophthalmologischen Eingriffen

Background and goal

Postoperative loss of vision is a rare, but devastating complication after non-ocular surgery. It can occur partially or completely and may involve one or both eyes. Since its etiology has not yet been solved, the purpose of this review was to extract potential causes from the case collections reported to propose prophylactic measures.

Methods

A literature search was performed using the “Pubmed” database of the US National Library of Medicine. MeSH terms and combinations used were: blindness, postoperative complications, ischemic optic neuropathy, not ophthalmological surgical procedures, not neurosurgical procedures. Additionally, the results of the interim analysis of the postoperative visual loss (POVL) registry of the ASA were considered.

Results

The incidence of permanent loss of vision after non-ophthalmologic surgery is reported to be 0.0008%. However, it is elevated up to 0.11% after cardiac and 0.08% after spine surgery. Risk factors seem to be perioperative anemia, arterial hypotension and prone position, but also pre-existing diseases such as arteriosclerosis. Thus hemodynamic stabilization or correction of anemia may be successful in therapy.

Conclusion

Patients with pre-existing arteriosclerotic disease scheduled for spine or cardiac surgery, but also for bilateral neck dissection should be informed preoperatively about the rare possibility of POVL. Postoperatively any visual changes should be immediately referred to an ophthalmologist and treated accordingly.     

Sudden blindness caused by anterior ischemic optic neuropathy in 5 children on continuous peritoneal dialysis

The authors report the occurrence of sudden blindness in 5 children (mean age, 32 months; range, 11 to 60) during continuous peritoneal dialysis regimen. All children presented with loss of light perception, visual fixation and ocular pursuit, and bilateral mydriasis unreactive to bright light. Fundoscopic examination found signs of anterior ischemic optic neuropathy with disc swelling, edema, and hemorrhages. Whereas 1 patient was dehydrated, the 4 other patients appeared well and not dehydrated. Nevertheless, blood pressure was below the normal range in all of them. Therefore, hypovolemia is highly suspected to have been the cause of ischemic optic neuropathy in all cases. Treatment consisted of steroids (4 patients), anticoagulation or antiagregation drugs (3 patients), plasma or macromolecules infusions (2 patients), vasodilatators (2 patients), and transient dialysis interruption (1 patient). One child with hepatic cirrhosis died 4 days later of acute liver insufficiency owing to ischemic hepatic necrosis. The other children had only partial improvement of vision during the following months. Because the prognosis of ischemic optic neuropathy is very poor, diagnosis and treatment of chronic hypovolemia in children on continuous peritoneal dialysis is essential to prevent such a devastating complication.     

Incidence of and risk factors for perioperative optic neuropathy after cardiac surgery

Background

Visual loss from optic neuropathy rarely occurs in the perioperative period in patients who have undergone nonocular surgery. We performed a retrospective, matched, case-control study to determine the incidence of perioperative optic neuropathy (PON) after cardiac surgery with the use of cardiopulmonary bypass (CPB) and to determine risk factors that may lead to this potentially devastating complication.

Methods

Medical records of all patients undergoing cardiac surgery during a 9-year period were reviewed retrospectively to identify visual loss from acute unilateral and bilateral optic neuropathy during the perioperative period that had developed in patients. Data were collected from these patients and compared with data from control subjects matched for age, gender, risk factors for vascular disease, and type of surgery to determine the incidence of and potential risk factors for PON.

Results

Of 9701 surgical patients requiring CPB, 11 patients (0.113%) with PON were identified. Although both the absolute and relative drop in hemoglobin during the perioperative period approached statistical significance, no other putative risk factors were identified.

Conclusions

The risk of PON associated with cardiac surgery in which CPB is used is low but substantial. The factors that lead to the condition remain unknown, although the presence of systemic vascular disease and both the absolute and relative drop in hemoglobin during the perioperative period seem to be important. Because PON often causes profound permanent visual loss, we recommend that patients, particularly those with systemic vascular disease, for whom cardiac surgery with CPB is planned, be made aware of this potential complication.     

Delayed ischemic optic neuropathy after surgery on skull base meningiomas successfully treated with nimodipine and rheological therapy: report of two cases

Two patients operated on because of skull base meningiomas experienced delayed ischemic optic neuropathy with loss of vision in one eye on days 6 and 12 after surgery. Treatment with nimodipine and rheological therapy was effective in restoring visual acuity. Possible pathophysiological mechanisms and treatment options are discussed.     

Delayed Ischemic Optic Neuropathy After Surgery on Skull Base Meningiomas Successfully Treated with Nimodipine and Rheological Therapy: Report of Two Cases

Two patients operated on because of skull base meningiomas experienced delayed ischemic optic neuropathy with loss of vision in one eye on days 6 and 12 after surgery. Treatment with nimodipine and rheological therapy was effective in restoring visual acuity. Possible pathophysiological mechanisms and treatment options are discussed.     

Postoperative blindness

This chapter discusses the cases of postoperative blindness reported in the literature and the theories that attempt to explain the mechanisms involved. Although uncommon, alterations in vision and blindness after anesthesia for major surgical procedures, particularly cardiopulmonary bypass or spine surgery, are well documented, with an incidence varying between 0.05% and 1%. Accurate incidence data are unavailable because it is not known what percentages are reported. However, the large number of case reports over many years has provided some significant information. Although sustained compression of the eye is an important cause, postoperative visual loss may also occur, in an unrelated manner, because of ischemic optic neuropathy, central retinal artery or vein occlusion, or cortical blindness.     

Urologic medications and ophthalmologic side effects: a review

Commonly prescribed urologic medications can have significant ophthalmologic side effects. The existing information can be conflicting. We looked at alpha-blockers and intraoperative floppy iris syndrome (IFIS), phosphodiesterase type 5 (PDE5) inhibitors and non-arteritic ischemic optic neuropathy (NAION) and lastly anticholinergic medications and glaucoma. There is no conclusive scientific data on what to do if the risk of urinary retention is low to moderate, however, we recommend that patients having cataract surgery should stop alpha-blocker medications preoperatively. If there is a high risk of urinary retention, the alpha-blocker should not be withheld, with the active involvement of the ophthalmologist. The role of using 5 alpha-reductase inhibitors (5ARIs) can be considered. There is no convincing evidence that PDE5 inhibitors cause non-arteritic anterior ischemic optic neuropathy (NAION), but patients should be advised of the possible risk of visual loss, especially in patients with risk factors of ischemic heart disease. Acute angle closure glaucoma (AACG or closed angle glaucoma) is very rarely caused by anticholinergic medications in patients with narrow angle anterior eye chambers. However, these medications are safe in patients with open angle glaucoma or treated closed angle glaucoma. Urologists should inquire about the patient’s glaucoma history from his/her ophthalmologist before starting an anticholinergic medication.     

Ischemic optic neuropathy following spine surgery

Perioperative visual loss (POVL) is a devastating injury that has been reported infrequently after nonocular surgery. The most common cause of POVL is ischemic optic neuropathy (ION). Increasing numbers of cases of ION are being reported after spine surgery, but the etiology of postoperative ION remains poorly understood. After a MEDLINE search of the literature, we reviewed published case reports of ION, specifically those reported after spine surgery performed with the patient in the prone position. Most of the cases involved posterior ION (PION, n = 17), and the remainder anterior (AION, n = 5). Most patients had no or few preoperative vascular disease risk factors. All except one PION and 2 of 5 AION cases reported symptom onset within the first 24 hours after surgery. Visual loss was frequently bilateral (40% of AION, 47% of PION cases). Mean operative time exceeded 450 minutes. The lowest average intraoperative mean arterial blood pressure was 64 mm Hg and the mean lowest intraoperative hematocrit was 27%. The average blood loss was 1.7 L for AION and 5 L for PION patients. PION patients received an average of 8 L of crystalloid solution and 2.2 L of colloid intraoperatively. This compilation of case reports suggests that a combination of prolonged surgery in the prone position, decreased ocular perfusion pressure, blood loss and anemia/hemodilution, and infusion of large quantities of intravenous fluids are some of the potential factors involved in the etiology of postoperative ION. However, levels of blood pressure and anemia intraoperatively were frequently at levels considered acceptable in anesthesia practice. The etiology of postoperative ION remains incompletely understood. Potential strategies to avoid this complication are discussed.     

Unusual presentation of perioperative ischemic optic neuropathy following major spine surgery

Perioperative visual loss following spinal surgery has become of increasing concern among anesthesiologists, surgeons, and patients alike. Perioperative ischemic optic neuropathy often occurs in patients greater than 50 years of age, in association with a number of presumed risk factors, including diabetes, hypertension, small cup-to-disc ratio, preoperative anemia, intraoperative hypotension, prolonged operative time in the prone position, and significant blood loss during surgery. The visual loss is notably devastating, and generally leads to permanent disability. A 44-year-old man whose central visual acuity was completely preserved is presented.