Cortical Blindness Following Spinal Surgery: Very Rare Cause of Perioperative Vision Loss

Abstract

A 38-year-old man was operated with posterior spinal decompression and pedicle screw instrumentation for his L2 fracture with incomplete neurological deficit. In the recovery, he complained of blindness in both eyes after twelve hours. Computed tomographic scan and magnetic resonance angiography revealed bilateral occipital lobe infarcts. He remained permanently blind even after three years follow-up. Though rare, perioperative vision loss is a potential complication following spine surgery in prone position. We report a rare occurrence of cortical blindness following lumbar spine surgery.

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POVL after Spine Surgery
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Asian Spine Journal Vol. 6, No. 4, pp 287~290, 2012
http: //dx.doi.org/10. 4184/asj.20 12.6.4.287
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2012 by Korean Society of Spine Surgery
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/)
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Asian Spine Journal • pISSN 1976-1902 eISSN 1976-7846
Received May 23, 2011: Revised Jun 24, 2011; Accepted Jun 30, 2011
Corresponding author: Sujit Kumar Tripathy, MS, DNB, Dip SICOT, MNAMS
Clinical fellow, Department of Orthopaedics, Friarage Hospital,
Northallerton, DL6 1JG, United Kingdom
Tel: +44-7423388617, E-mail: sujitortho@yahoo.co.in
Cortical Blindness Following Spinal Surgery: Very Rare Cause of
Perioperative Vision Loss
Vijay Goni
1
, Sujit Kumar Tripathy
1,2
, Tarun Goyal
1,3
, Tajir Tamuk
1
, Bijnya Birajita Panda
4
, Shashidhar BK
1
1
Department of Orthopaedics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
2
Department of Orthopaedics, Friarage Hospital, Northallerton, United Kingdom
3
Department of Orthopaedics, Freeman Hopstal, Newcastel upon Tyne, United Kingdom
4
Department of Opthalmology, SCB Medical College, Cuttack, India
A 38-year-old man was operated with posterior spinal decompression and pedicle screw instrumentation for his L2 fracture
with incomplete neurological deficit
.
In the recovery
,
he complained of blindness in both eyes after twelve hours
.
Computed
tomographic scan and magnetic resonance angiography revealed bilateral occipital lobe infarcts
.
He remained permanently
blind even after three years follow-up
.
Though rare
,
perioperative vision loss is a potential complication following spine
surgery in prone position
.
We report a rare occurrence of cortical blindness following lumbar spine surgery
.
Key Words: Blindness
,
Prone
,
Surgery
,
Spinal injuries
,
Postoperative vision loss
Introduction
Vision loss is a very rare but devastating complication
of nonocular surgeries, and reported incidence is 0.003%
to 0.0008% in the general surgical population [1]. The risk
of perioperative vision loss (POVL) has been commonly
noted after cardiac and spinal surgeries. The incidence as
reported in literature is 8.64/10,000 for cardiac surgeries and
3.09/10,000 for spinal fusions [2].
Most cases of perioperative vision loss following spine
surgery are mentioned as case reports in literature [3-8].
The specic pathogenesis of POVL remains elusive in most
cases, with much controversy surrounding patient and surgi-
cal risk factors. Important causes of POVL include ischemic
optic neuropathy (ION), retinal vascular occlusion (RVO)
and cortical blindness. Among these major causes, cortical
blindness is the rarest cause of POVL [7-9]. Myers et al.
[7] reported only three cases of cortical ischemia leading to
blindness while reviewing 37 patients of POVL after spine
surgery. Because of the rarity of occurrence and as most of
the data are retrospective, it is difcult to establish denite
cause-effect relationship for the cortical blindness. In this
article we report a case of POVL secondary to cortical isch-
aemia in a 38-year-old man following lumbar spinal fusion
without any predisposing factors for vaso-occlusive disease.
Case Report
A 38-year-old manual labourer was brought to the emer-
gency after a high energy motor vehicle accident. He was
hemodynamically stable at the time of admission. On pri-
mary and secondary survey a lumbar spine fracture possibil-
ity was suspected. Radiographic evaluation conrmed our
diagnosis and X-ray showed fracture of the second lumbar
vertebra (Fig. 1A). Neurologically he had diminished power
in both lower limbs (motor power of grade 3 or less around

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ASJ: Vol. 6, No. 4, 2012
hip, knee and ankle joints). He had complete loss of bladder
and bowel sensations, but no sensory impairment was elic-
ited in the lower limbs.
His past medical history was not suggestive of any neuro-
logical problems, vision problems, diabetes, hypertension,
coronary artery disease, deep vein thrombosis, peripheral
vascular disease, collagen vascular disorder or previous
chest or heart problems. He was a non smoker and a social
drinker. His body mass index was 32.4.
Magnetic resonance imaging of the lumbar spine was per-
formed to better delineate the severity of spinal cord injury
and compression (Fig. 1B). He was operated after 72 hours
of injury. Surgery was carried out with posterior decompres-
sion and fusion using pedicle screw instrumentation in the
prone position under general anaesthesia (Fig. 2). Constant
monitoring of the arterial blood pressure was performed
during the surgery. Total duration of surgery was 105 min-
utes. Perioperative blood loss was 420 ml. Systolic blood
pressure throughout the surgery was in the range of 90 to
110 mm Hg. The oxygen saturation as measured by pulse
oxymeter was above 98% at all times. There was no other
anaesthetic or surgical complication intraoperatively. In
the recovery, patient complained of complete loss of vision
after twelve hours. He was evaluated by an ophthalmolo-
gist, neurologist and a cardiologist. His ocular examination
revealed complete bilateral loss of vision with preservation
of papillary and corneal reexes and normal ocular move-
ments. Intraocular pressure and fundus examination were
within normal limits. There was no new neurological decit
occurring after surgery and his cerebellar functions were
intact. His postoperative haemoglobin was 10.6 g and he
did not require any blood transfusion in the perioperative
period.
The computed tomographic scan and magnetic resonance
angiography of the brain revealed infarcts in bilateral oc-
cipital lobes (Fig. 3). Electrocardiography and echocardiog-
raphy evaluation for underlying cardiac problem did not
reveal any cardiac source of emboli. He was treated by the
ophthalmologist, but no recovery in vision was observed
even after three years follow-up.
Discussion
The article by Berg et al. [10] was surprising to the spine
surgeons where they mentioned that the incidence of POVL
following ocular surgeries is much lower than that seen in
nonocular surgeries. Incidence estimates for POVL after
nonocular surgery range from 0.013% for all surgeries up to
0.2% following spine surgery. Ischemic optic neuropathy is
the most common cause of POVL accounting for more than
81%, followed by retinal artery thrombosis. Cortical blind-
ness is the rarest cause of POVL with a handful of cases in
the literature [11].
Work up of a patient with perioperative visual loss in-
volves consideration of anatomy of the visual pathway.
Anterior ischemic optic neuropathy and retinal vascular oc-
clusion reveal remarkable changes on fundus examination,
but no such changes are observed in posterior ischemic op-
tic neuropathy (PION). The diagnosis in PION can be made
Fig. 1. Radiograph (A) and magnetic resonance imaging (B)
of the lumbar spine showing fracture of the L2 vertebra (ar-
row).
A B
Fig. 2. Radiogarphs (antero-posterior and lateral views)
after posterior spinal decompression and pedicle screw xa-
tion for L2 vertebra fracture.
A
B

POVL after Spine Surgery
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by contrast enhancement seen in the optic nerve on ocular
magnetic resonance imaging. Cortical blindness is diag-
nosed by looking for the ischemic changes in the occipital
lobe on intracranial imaging. In our case, the diagnosis was
made by cortical occipital changes seen on magnetic reso-
nance imaging with the absence of fundoscopic examina-
tion ndings.
Despite numerous efforts and explanations, pathogenesis
of POVL is still elusive. Various aetiologies’ such as fall in
systemic blood pressure, anaemia, direct ocular compres-
sion, hypercoagulable states, embolism, increased venous
pressure, prone positioning during surgery and increased
cerebrospinal uid pressure have been elucidated but none
has proved so far [12-15]. Two important factors in cortical
blindness are generalised cerebral hypoperfusion and em-
bolism. It has been suggested that more than one factor may
be working in any patient making this a multifactorial event
[7,10]. Pathogenesis in cardiac surgery is relatively easy to
explain. Embolisation may take place due to cardiac and
great vessel manipulation, atrial or ventricular brillation [7].
The source of emboli in spinal surgery is difcult to explain.
It is also unclear why this phenomenon is commoner in sur-
geries carried out in the prone position. Direct pressure on
eye, raised intraocular pressure or vascular congestion does
not explain cortical infarcts, but may explain other causes of
vision loss such as ION and RVO. Intraoperative hypoten-
sion, hypoxia, blood loss and anaemia are contributory fac-
tors, but are not found in this patient. Further, they should
classically affect the watershed areas of blood supply in the
brain which innervate the proximal muscles of upper and
lower limb. Also, it has been shown that the use of deliber-
ate hypotensive anaesthesia during spine surgery does not
increase chances of POVL [7]. Huber and Grob [8] sug-
gested that abnormal posture of the neck when the patient is
being positioned prone for surgery could be a contributory
factor for reducing perfusion in the vertebra-basilar area
manifesting as stroke. This is purely hypothetical thought
and cannot be denitively proved. It has been recommended
to keep the neck at the level of heart or above in a neutral
forward position at the time of surgery to avoid chances of
hypoperfusion due to vertebra-basilar compression. The
bilateral infarction as in the present case does not support
the hypothesis. Review of POVL following general surger-
ies include many procedure carried out in the lower limb in
prone position [7,16]. Irrespective of the types of surgeries,
the prone position itself is a predisposing factor for POVL.
Shen et al. [2] found some important nding on periopera-
tive visual loss following spinal surgeries. Incidences were
higher for age less than 18 or more than 65 years, male
gender, anaemia, and posterior approach. Many cases occur
in patients who have no identied preoperative risk factors,
although hypertension, smoking, diabetes, and vascular dis-
ease appear to lead to increased risk. None of these risk fac-
tors was present in this patient. He had no cardio-pulmonary
comorbidities and he had no fluctuation in hemodynamic
status in the perioperative period as well. Considering these
situations, other than the prone position we could not nd
any predisposing condition in our case.
Most of patients with cortical blindness have a partial vi-
sion loss. They often have other associated symptoms such
Fig. 3. Magnetic resonance angiography of brain reveals bilateral infarction of occipital lobe.

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ASJ: Vol. 6, No. 4, 2012
as cerebellar signs and other focal neurological decits, de-
pending upon the area of infarct. This patient had purely vi-
sion loss with no other decit. There is no denite treatment
for cortical blindness. No drugs including steroids have
shown to reduce morbidity in these cases and most postop-
erative visual decits do not show signicant improvement
with time. There is a hope of some improvement in initial
months, but once the window time period has passed there
is no hope of any further improvement.
This case report warns the spine surgeon about such fatal
complication following spine surgery in prone position. Ex-
treme cautions at every step should be taken to prevent the
development of perioperative visual loss. Despite these pre-
cautions, some cases may still land up with visual loss and
the patient should be explained about the grievous situation
well before the surgical procedure.
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