Inadvertent intraocular injection of methylprednisolone in a patient with prior superior oblique tuck surgery

To report inadvertent intraocular methylprednisolone injection into an eye that had previously undergone superior oblique tuck surgery. An observational case report. An inadvertent intraocular penetration occurred following periorbital methylprednisolone injection, which was performed via the superonasal quadrant to relieve trochlear pain in an eye that had undergone previous superior oblique tuck procedure. There was immediate loss of vision, afferent pupillary defect, and raised intraocular pressure. Fundoscopy revealed intravitreal and subretinal methylprednisolone with retinal detachment. Immediate removal of intravitreal and subretinal methylprednisolone was performed with a retinal reattachment procedure. Postoperatively, retinal necrosis was noted in the area that was in contact with methylprednisolone. This case highlights the risk of inadvertent intraocular penetration while injecting through a limited periorbital space that has been previously operated on.


Introduction
Methylprednisolone injection is a corticosteroid commonly used for treating ocular inflammatory conditions.It is important to note that its use is limited to extra-ocular administration due to the attributed toxicity primarily associated with the vehicle myristylgamma-picolinium chloride (MGP), rather than the corticosteroid itself [1].Experimental evidence has shown substantial retinal toxicity in rabbits when the vehicle itself was injected into the vitreous at a concentration double that of the manufacturer's recommendation [2].In this context, we present a case involving retinal necrosis following an unintentional intraocular injection of methylprednisolone in the trochlear region.This incident occurred subsequent to a previous surgical procedure involving superior oblique tuck surgery.

Case description
A 28-year-old white woman presented to the neuroophthalmology clinic with a diagnosis of right congenital superior oblique palsy.Her Snellen visual acuity was 6/6 in both eyes.Initially, she underwent inferior oblique disinsertion followed by superior oblique tuck to alleviate her diplopia.However, 1 year after the superior oblique surgery, she began experiencing pain in the trochlear area.The pain persisted despite the use of oral analgesics, necessitating a referral to the pain clinic.Given the persistent nature of the pain, all available options were discussed, including the reversal of the superior oblique tuck surgery and the possibility of a superonasal periocular injection of methylprednisolone.While injecting 40 mg/mL methylprednisolone around the trochlear area, the patient complained of severe pain, prompting the surgeon to halt the drug administration.A total of 0.8 mL of the drug had been injected.On immediate examination, there was no perception of light, with a relative afferent pupillary defect (RAPD) and an intraocular pressure (IOP) of 70 mm Hg noted.Paracentesis was immediately performed, the IOP was reduced to 20 mm Hg, and perception of light returned.Fundoscopy revealed intravitreal and subretinal methylprednisolone with overlying macula-on retinal detachment due to a ragged tear in the retina.
The patient was promptly transferred to the vitreoretinal team and underwent vitrectomy within 3 h of injection.During the surgery intravitreal methylprednisolone was completely removed but only partial removal of subretinal methylprednisolone was achieved through the retinal tear, which was noted superonasally at 2 o'clock (Fig. 1a, b).The retina was attached with silicone oil.On postoperative day 1 there were numerous scattered retinal hemorrhages with residual subretinal methylprednisolone (Fig. 2).
At 4 months following the initial procedure, silicone oil removal was performed in conjunction with an epiretinal membrane peel.This was followed by cataract surgery and the placement of an intraocular lens.Throughout the process, the retina remained attached, and at the last follow-up at 12 months, the patient achieved a final visual acuity of 6/36.

Discussion
This case highlights the potential complications that can arise during periorbital injection in an eye that has undergone previous muscle surgery.In our particular case, the patient had undergone prior superior oblique tuck surgery, which might have led to anatomical alterations resulting from localized scarring in the already limited superonasal periorbital space [3].This potential scarring could have contributed to the misdirection of the needle, leading to inadvertent penetration.This case serves as a valuable lesson, emphasizing the need for utmost caution when administering a periocular injection in a quadrant that has undergone previous surgical intervention.
The reported degrees of retinal toxicity and visual outcomes associated with accidental intraocular methylprednisolone injection have varied [4][5][6][7][8].Some reports indicate favorable visual outcomes with observation alone [4,5] or prompt vitrectomy [6], others describe poor visual outcomes and retinal damage despite immediate vitrectomy [7,8].This suggests that the retinal toxicity observed in our patient, despite undergoing immediate vitrectomy, could potentially be attributed to the amount of vehicle in direct contact with the retina.
Although periorbital steroid injections are commonly used for managing inflammation, inadvertent intraocular injection can occur, leading to devastating complications and poor visual outcomes.In our case, despite an early vitrectomy, the visual outcome remained poor.It is possible that the manipulated superonasal orbital space during the tuck procedure may have caused the incident, and the larger amount of subretinal methylprednisolone deposit could have contributed to retinal toxicity.Therefore, we recommend including a discussion on accidental intraocular injection and its potential outcomes as part of the consent process.
Funding All authors declare that they received no funding for this study.
Author Contribution All authors participated in the planning, research and writing of the final manuscript, as well as reviewing and rewriting of the revised version.
Funding Open access funding provided by HEAL-Link Greece.

Declarations
Conflict of interest V. Felcida, A.K. Tyagi and D. Kalogeropoulos declare that they have no competing interests.

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Fig. 3
Fig. 3 Follow-up optical coherence tomography (OCT).OCT infrared reflection image showing retinal necrosis (arrow) (a) and B-scan OCT image on the right showing gross thinning of the retina (b)