Main

Sir,

Fiberoptic epidural endoscopy to visualize the spinal cord and subarachnoid space has been considered a safe procedure to lyse adhesions or to inject steroids into inflamed tissues that could contribute to the low-back pain associated with persistent lumbar radiculopathy.1 Acute bilateral visual loss associated with retinal haemorrhages after epiduroscopy has been documented in only two cases so far.2, 3 This report describes acute bilateral central scotomas with relatively spared visual acuity in a patient following endoscopic spinal surgery.

Case report

A 41-year-old woman who had a 2-year history of lumbar postlaminectomy syndrome with left lumbar radiculopathy unresponsive to medical management, underwent an endoscopic spinal surgery for adhesiolysis under intravenous sedation. Her vital signs remained stable throughout the procedure. Immediately after the procedure, she noted blurry vision with bilateral central scotomas.

Ocular examination at that time revealed a best-corrected visual acuity of 20/80 OU. Intraocular pressures and pupils were within normal limits. Amsler grid examination revealed bilateral absolute central scotomas. Anterior segment examination revealed a deep anterior chamber and no cells. Dilated funduscopic examination was remarkable for bilateral perimacular subretinal petaloid hemorrhages (Figure 1). Fluorescein angiography revealed blockage of choroidal fluorescence corresponding to these areas of retinal hemorrhages. After 2 months, her best-corrected visual acuity was 20/20 OU and her bilateral scotomas and retinal hemorrhages resolved spontaneously.

Figure 1
figure 1

Ocular fundus photographs of the right (a) and left (b) eyes demonstrate multiple retinal haemorrhages involving the posterior pole.

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Comment

It has been hypothesized that sudden increased cerebrospinal fluid (CSF) pressure transmitted through the optic nerve sheaths to the retinal veins may cause retinal hemorrhages if the dura is inadvertently punctured and fluid is infused into the subarachnoid space.3 In this patient, spinal endoscopy was performed through the anterior epidural compartment. This space is considered less expansile than the posterior epidural compartment. Injection of fluid with a higher viscosity, such as Hespan in this case, into the subarachnoid space could contribute to a hydrostatic pressure high enough to cause immediate bilateral retinal hemorrhages. In addition to higher viscosity, increased injection rate and volume may contribute to the risk of developing these ocular complications.4

Other similar cases in the literature have demonstrated the presence of hemorrhages in no particular configuration in all layers of the retina, suggestive of extravasation of blood within the subretinal, intraretinal, preretinal, and subhyaloid planes.3, 5 This patient had retinal hemorrhages in a petaloid configuration (Figure 2) that appears to be subretinal.

Figure 2
figure 2

The petaloid configuration of the retinal haemorrhages resemble the spokes of a wheel in this fluorescein angiogram of the right eye.

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Unlike the two previously reported cases of severe visual loss after epiduroscopy, this report demonstrates that its visual complications do not always result in immediate blindness. This patient presented with blurry vision and bilateral scotomas. Her good visual outcome of 20/20 OU provides further evidence that patients with such complications may have an excellent visual prognosis. Her spontaneous recovery is also consistent with the clinical course of her more superficial retinal hemorrhages.