Introduction: Perioperative visual loss (POVL) owing to hemi-retinal vein occlusion (HRVO) following prone positioning during spinal surgery is rare. Here, we report a case of HRVO with macular edema (ME) after spinal surgery that was successfully treated with intravitreal aflibercept (IVA) injections and retinal photocoagulation (RP). Case Presentation: A 63-year-old Japanese man underwent spinal surgery for lumbar spinal canal stenosis. Surgery was performed with the patient in the prone position under general anesthesia; the operation time was 305 min. No complications were associated with intraoperative anesthesia. On postoperative day 4, the patient noticed decreased visual acuity in his left eye and visited the Department of Ophthalmology on postoperative day 9. The best-corrected visual acuity (BCVA) in the left eye was 0.1. Fundus and optical coherence tomography revealed HRVO and ME in the left eye. IVA injections and RP were performed in the eye, which substantially decreased the ME and improved the patient’s BCVA to 0.8. Conclusions: HRVO can cause POVL after prone positioning during spinal surgery. This is the first case of HRVO with ME after spinal surgery, which was successfully treated with IVA injections and RP.

Perioperative visual loss (POVL) following prone positioning during spinal surgery is rare [1‒4]. Patil et al. [3] reported an incidence of 0.094% of POVL among 4,728,815 patients who underwent spinal surgery in the prone position, and Nandyala et al. [4] reported 0.019% of 541,485 cases. However, POVL can lead to severe, irreversible visual impairment. POVL due to prone positioning in spinal surgery is chiefly attributed to arterial occlusion, with arterial ischemic optic neuropathy being the first most common cause, followed by central retinal artery occlusion, cortical blindness, and acute angle closure glaucoma; however, retinal vein occlusion (RVO) is rare [1‒4].

Macular edema (ME) is one of the major complications of RVO, including hemi-retinal vein occlusion (HRVO) and central retinal vein occlusion (CRVO). The vascular endothelial growth factor (VEGF) levels are increased in the vitreous fluid of patients with CRVO and play crucial roles in ME pathogenesis by increased vascular permeability. Several phase 3 and 4 clinical studies have demonstrated the efficacy and safety of intravitreal aflibercept (IVA) injections in ME with CRVO [5, 6]. We present a case of HRVO with ME after prone positioning during spinal surgery, which was successfully treated with IVA injections and retinal photocoagulation (RP).

A 63-year-old Japanese man (height: 180 cm, weight: 56 kg, body mass index: 20.7 kg/m2) with a history of rheumatoid arthritis and hyperuricemia underwent spinal surgery for lumbar spinal canal stenosis at the Department of Orthopedic Surgery, Oita Red Cross Hospital. The patient had no history of hypertension or heart disease. Surgery was performed with the patient in the prone position under general anesthesia; the operation time was 305 min. The anesthesiologist repeatedly confirmed that neither eye was compressed. The intraoperative infusion, bleeding, and urine volumes were 2,050 mL, 270 mL, and 1,200 mL, respectively. Blood transfusion was not performed, and hypotension was not observed during surgery.

On postoperative day 4, the patient noticed decreased visual acuity in the left eye. On postoperative day 9, he visited the Department of Ophthalmology, Oita Red Cross Hospital. Initial examination revealed that the best-corrected visual acuity (BCVA) was 1.2 and 0.1 in his right and left eye, respectively. Fundus examination of the left eye revealed retinal hemorrhage around the optic disk, cotton wool spots along the inferior temporal arcade, narrowing of the inferior arcade vein, and ME. No specific findings were observed in the right eye. The patient was diagnosed with HRVO and ME of the left eye. The patient was referred to Oita University Hospital on postoperative day 17.

The findings recorded at the Oita University Hospital were as follows: BCVA of 1.0 and 0.1 in the right and left eye, respectively, and intraocular pressure (IOP) values of 16 mm Hg (right eye) and 12 mm Hg (left eye). Neither eyelid swelling nor exophthalmos was observed. Fundus examination revealed a retinal hemorrhage, cotton wool spots, and narrowing of the inferior arcade vein (Fig. 1a). Optical coherence tomography revealed ME in the left eye (Fig. 1b, c). Fluorescein angiography and indocyanine green angiography revealed a non-perfusion area in the inferior retina of the left eye (Fig. 1d).

Fig. 1.

Fundus photo, OCT images, FA, and ICGA at the patient’s first visit at Oita University Hospital. The fundus photo (a), OCT (b: horizontal section, c: vertical section), and the images of FA (d, left) and ICGA (d, right) of his left eye at the first visit of the patient, a 63-year-old male. The fundus photo shows retinal hemorrhage, cotton wool spots, and narrowing of the inferior arcade vein (a), and OCT shows ME (b, c). The FA and ICGA of the left eye revealed an NPA of the inferior retina (d). BCVA at the first visit was 0.1. OCT, optical coherence tomography; FA, fluorescein angiography; ICGA, indocyanine green angiography; NPA, non-perfusion area.

Fig. 1.

Fundus photo, OCT images, FA, and ICGA at the patient’s first visit at Oita University Hospital. The fundus photo (a), OCT (b: horizontal section, c: vertical section), and the images of FA (d, left) and ICGA (d, right) of his left eye at the first visit of the patient, a 63-year-old male. The fundus photo shows retinal hemorrhage, cotton wool spots, and narrowing of the inferior arcade vein (a), and OCT shows ME (b, c). The FA and ICGA of the left eye revealed an NPA of the inferior retina (d). BCVA at the first visit was 0.1. OCT, optical coherence tomography; FA, fluorescein angiography; ICGA, indocyanine green angiography; NPA, non-perfusion area.

Close modal

An IVA injection was administered to the left eye on the first day and at 1 and 2 months following the first day, as planned. ME decreased substantially after the first IVA injection (Fig. 2a, b). RP was performed on the entire inferior retinal non-perfusion area in the left eye. ME relapse was observed 6 months after the initial IVA injection (Fig. 2c, d), which promptly decreased upon receiving an additional IVA injection (Fig. 2e, f). Fundus examination 9 months after the initial visit revealed only narrowing of the inferior arcade vein and a scar from the RP in the inferior area of the retina. Retinal hemorrhage and cotton wool spots were not detected, the caliber of the retinal artery returned to normal (Fig. 3a), and no ME was detected (Fig. 3b, c). There was a segmental retinal thinning and nerve fiber loss in the inferior area on vertical sections of optical coherence tomography (Fig. 2f, 3c). The BCVA of the left eye improved to 0.8, and the IOP was 13 mm Hg. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000539343).

Fig. 2.

OCT images after IVA injections. OCT images at 1 month (a: horizontal section, b: vertical section), 6 months (c: horizontal section, d: vertical section), and 7 months (e: horizontal section, f: vertical section) after the first visit. ME was substantially decreased after the first IVA injection (a, b). A relapse of ME after 6-month treatment with the initial IVA injection was observed (c, d), which was promptly decreased by an additional IVA injection (e, f). There were segmental retinal thinning and nerve fiber loss in the inferior area on vertical section of OCT (f). OCT, optical coherence tomography.

Fig. 2.

OCT images after IVA injections. OCT images at 1 month (a: horizontal section, b: vertical section), 6 months (c: horizontal section, d: vertical section), and 7 months (e: horizontal section, f: vertical section) after the first visit. ME was substantially decreased after the first IVA injection (a, b). A relapse of ME after 6-month treatment with the initial IVA injection was observed (c, d), which was promptly decreased by an additional IVA injection (e, f). There were segmental retinal thinning and nerve fiber loss in the inferior area on vertical section of OCT (f). OCT, optical coherence tomography.

Close modal
Fig. 3.

Fundus photo and OCT images at the last visit. The fundus photo (a) and OCT images (b: horizontal section, c: vertical section) at the last visit (9 months after the first visit). The fundus photo shows only narrowing of the inferior arcade vein and the scar from RP in the inferior area of the retina (a), and there is no ME (b, c). Segmental retinal thinning and nerve fiber loss were still seen in the inferior area (c). BCVA had improved to 0.8 at that time. OCT, optical coherence tomography.

Fig. 3.

Fundus photo and OCT images at the last visit. The fundus photo (a) and OCT images (b: horizontal section, c: vertical section) at the last visit (9 months after the first visit). The fundus photo shows only narrowing of the inferior arcade vein and the scar from RP in the inferior area of the retina (a), and there is no ME (b, c). Segmental retinal thinning and nerve fiber loss were still seen in the inferior area (c). BCVA had improved to 0.8 at that time. OCT, optical coherence tomography.

Close modal

Here, we present a case of HRVO with ME after prone surgery, which was successfully treated with IVA injections and RP. The mechanism of RVO after spinal surgery could not be clearly identified in this case. One possible mechanism of RVO is elevated IOP. Elevated IOP, which is a risk factor for CRVO and HRVO [7], is observed even in awake and healthy participants when measured in the prone position [8]: the median IOP in the sitting position was 15.0 mm Hg, which rose to 22.5 mm Hg when the prone position was maintained. Cheng et al. [9] observed that the mean IOP significantly increased to 40.0 mm Hg after prone positioning in a 320-min spinal surgery from a baseline mean IOP of 19.0 mm Hg. The operation time for the patient in the current case report was 305 min, which is nearly the same as that in the abovementioned report, suggesting that the elevation of IOP due to prolonged prone positioning during spinal surgery led to HRVO.

POVL due to orbital compartment syndrome has been reported as a complication of prolonged supine positioning during spinal surgery [10‒12]. Urgent computed tomography (CT) or magnetic resonance imaging (MRI) in patients with severe orbital compartment syndrome with clinical signs, such as bilateral proptosis, painful eyelid swelling, and severe visual loss immediately after spinal surgery in the prone position, revealed extraocular muscle enlargement or stretching of the optic nerve [10‒12]. Das et al. [13] reported a case of orbital abscess resulting in orbital pressure elevation and subsequent CRVO, indicating that intraorbital pressure elevation, not as high as that in orbital compartment syndrome, might contribute to the development of RVO; however, the patient in our case report did not develop bilateral proptosis, painful eyelid swelling, or severe vision loss immediately after surgery. Because our patient did not exhibit any of these findings, we did not suspect orbital compartment syndrome and did not perform CT or MRI. CT or MRI should be performed to confirm the presence of orbital compartment syndrome for the patient with POVL after prone surgery.

ME is a vision-threatening complication of both HRVO and CRVO. Anti-VEGF therapy has recently become the first-line treatment for ME secondary to CRVO [14]. The COPERNICUS and GALILEO studies revealed that IVA injections significantly improved the BCVA and decreased the central retinal thickness of patients with ME secondary to CRVO [5, 6]. In our patient, IVA injections improved the BCVA and ME. After three monthly IVA injections, we switched to a pro re nata (as needed) regimen. Only one relapse of ME was observed, which was promptly cured with an additional IVA injection. RP was also performed in the inferior ischemic retinal area attributed to HRVO. RP is performed at the ischemic retina to reduce the oxygen demand and subsequent production of VEGF [15]. Thus, ME in our patient was successfully managed with IVA injections and RP. To our knowledge, this is the first reported case of HRVO with ME in which POVL was successfully treated using IVA injections and RP.

In conclusion, we treated a patient with HRVO and ME after spinal surgery, which are extremely rare causes of POVL. After multiple IVA injections and RP, ME substantially improved and the patient’s BCVA arose from 0.1 to 0.8. However, the mechanisms underlying HRVO after prone positioning during spinal surgery remain unclear. Our patient noticed a decrease in the BCVA on postoperative day 4. Thus, the patient’s visual acuity should be monitored for several days following spinal surgery.

We would like to thank Editage (www.editage.jp) for English language editing.

Written informed consent for publication was obtained from the patient for the publication of details of their medical case and any accompanying images. This case study was approved by the Ethics Committee of the Oita University Hospital (approval number 2085).

The authors have no conflicts of interest to declare.

This study was supported by grants from the Japan Society for the Promotion of Science (JSPS) through JP24K12810 (Grant C to A.T.) and the Ministry of Education, Science, Sports, and Culture of Japan (Tokyo, Japan).

S.N., Y.S., and M.I. collected the data. S.N. drafted the manuscript. K.K., T.K., and A.T. critically revised the manuscript.

The data that support the findings of this study are not publicly available due to their containing information that could compromise the privacy of research participants, but are available from the corresponding author S.N. upon reasonable request.

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