Surgical management of a live intravitreal nematode.

PURPOSE: To describe a novel surgical technique for the removal of a live intravitreal nematode. OBSERVATIONS: We describe the surgical management of a 35-year-old man with a live intravitreal nematode in his left eye. A 23-gauge pars plana limited core vitrectomy was performed to release the nematode from the surrounding vitreous strands. After creating a peritomy, a 20-gauge full thickness sclerotomy was created with a microvitreoretinal blade. The tip of a 20-gauge angiocath needle was cut obliquely and inserted through the sclerotomy. The external portion of the needle was attached to the viscous fluid extraction tubing for the Constellation vitrectomy machine (Alcon). Gentle aspiration pulled the nematode into the angiocath. The nematode was transferred to a syringe for parasitologic evaluation. CONCLUSIONS AND IMPORTANCE: The novel surgical technique described allows for aspiration of an intravitreal nematode in a controlled fashion. This technique can be used to manage this rare, but visually significant condition.

Introduction

A 35-year-old man of Bangladeshi origin presented with a six-week history of left eye pain, blurriness, photophobia and floaters. On examination, he was found to have a non-mobile nematode suspended within the vitreous humor of his left eye (Fig. 1). While parasitic infections are common in many developing countries, ocular involvement and in particular intravitreal involvement is rare. Previous reports have described using a 20-gauge flute needle to aspirate the nematode; introducing a 19-gauge cut down needle into the vitreous cavity and then raising the intraocular pressure to passively push the worm through the needle into a syringe; or leaving vitreous strands around the worm and grasping these vitreous strands to remove the worm. We describe a novel technique for the removal of an intravitreal nematode.

Fig. 1

Preoperative wide-field fundus photograph of the nematode in the vitreous cavity.

Case report

The nematode, as seen in this video, was removed via a 23-gauge pars plana vitrectomy with chandelier illumination (see Surgical Video, Supplemental Digital Content 1). The nematode was clearly identified in the vitreous cavity (Fig. 2). A limited core vitrectomy was performed to release the nematode from the surrounding vitreous strands. A bimanual approach allowed the nematode to be uncurled using intraocular forceps. A superotemporal conjunctival peritomy was performed using 0.12 mm forceps and Westcott scissors. A microvitreoretinal blade was used to create a 20-gauge full thickness sclerotomy. The tip of a 20-gauge angiocath needle was shortened and cut obliquely to facilitate insertion through the sclerotomy. The external portion was attached to the viscous fluid extraction tubing for the Constellation vitrectomy machine (Alcon), while the internal portion was positioned adjacent to the nematode (Fig. 3). Gentle aspiration pulled the nematode into the angiocath which was kept stationary in the vitreous cavity as the nematode was not yet completely freed from the vitreous strands, especially posteriorly as it was not previously possible to remove this vitreous without increased risk of compromising the specimen. Once the nematode was safely inside the angiocath, the remaining adhesions to the vitreous were cut and the angiocath removed. Aspiration of balanced salt solution in a bowl was carried out until the nematode was visually confirmed to be in the syringe. The syringe was then sent for parasitologic evaluation. An inferior retinal break occurred during the induction of a posterior vitreous detachment of the very adherent hyaloid. Endolaser was applied in the area of this retinal break and the vitrectomy was completed. An air-fluid exchange was performed and 20% sulfur hexafluoride (SF6) gas was injected at the end of the case. The 20-gauge sclerotomy was closed with a 7-0 Vicryl suture.

Fig. 2

Intraoperative visualization of the nematode.

Fig. 3

A bimanual approach is used here to allow the nematode to be aspirated into the angiocath needle with subsequent freeing of the remaining vitreous adhesions to the nematode using the cutter.

Supplementary video related to this article can be found at https://doi.org/10.1016/j.ajoc.2020.100721

The following is the supplementary data related to this article:

Supplemental Digital Content 1

Surgical Technique - nematode removal.

Unfortunately, the microbiology department was unable to speciate the nematode. A thorough systemic evaluation by the infectious diseases department did not reveal any systemic involvement. As such, a systemic anti-helminthic agent was not initiated.

Discussion

There is limited literature on the management of an intravitreal nematode. Our technique builds upon earlier methods by using an angiocath needle connected to the viscous fluid extraction tubing of the Constellation to aspirate the worm in a gentle and more controlled fashion than would be possible with a syringe whose plunger was controlled by an assistant. The use of chandelier illumination allowed for bimanual surgery with the concurrent use of the angiocath needle and the cutter. The vitreous could then be easily removed using the cutter while the worm was protected inside the angiocath needle.

Conclusions

The novel surgical technique described allows for aspiration of an intravitreal nematode in a controlled fashion. This technique can be used to manage this rare, but visually significant condition.

Patient consent

The patient consented to publication of the case in writing.

Funding

No funding or grant support.

Authorship

All authors attest that they meet the current ICMJE criteria for Authorship.

Declaration of competing interest

None of the authors have any financial disclosures.