Midline sclerotomy approach for intraocular foreign body removal in phakic eyes using endoilluminator: A novel technique.

Purpose: The objective of this study is to describe the removal of retained intraocular foreign body (RIOFB) by bimanual pars plana vitrectomy through midline sclerotomy in phakic patients. Technique: Four eyes with RIOFB and clear lens underwent microincision vitrectomy surgery. A chandelier illumination was placed through one of the existing ports. The foreign body (FB) was localized by direct visualization (intravitreal) or indentation (pars plana), stabilized using an intraocular magnet/FB forceps introduced through a midline sclerotomy and freed of vitreous from all sides using a vitrectomy cutter through the other port bimanually, reoriented along their long axis and extracted through the midline sclerotomy.
Results: All four FBs were removed successfully without slippage or damage to the clear lens.
Conclusion: Chandelier illumination-assisted removal of FB through midline sclerotomy helps in easier localization, stabilization and removal, avoiding lens touch even in anteriorly located FBs such as at pars plana.

Retained intraocular foreign body (RIOFB) is a common occurrence following open globe injury.[1] Numerous surgical techniques have been described for its safe and complication free removal including limbal route, “magnet handshake” and use of chandelier illumination system after removal of lens[23456789] In phakic eyes, inadvertent lens damage can occur by the foreign body (FB) or the instruments while removal. More so, anteriorly lodged FBs at pars plana may involve blind steps during their removal through external route or require lensectomy/phacoemulsification before vitrectomy when attempting internal approach to prevent undesirable outcomes. Herein, we describe a novel technique with chandelier illumination assisted bimanual FB removal through midline sclerotomy preventing injury to the crystalline lens. It also helps to maneuver the IOFB into the desired axis during extraction, thereby decreasing the size of incision needed.

Technique

Initially, a conventional three-port, pars plana vitrectomy is initiated. 23 or 25 G nonvalved ports are made. A limited core vitrectomy is done followed by a triamcinolone-assisted controlled slow posterior vitreous detachment (PVD) induction in all quadrants. For intravitreal FB, as they tend to lift with the hyaloid, a low vacuum is required while vitrectomy to avoid inadvertent fall on retina. Vitrectomy in PropVac mode of constellation vision system® (Alcon Laboratories, Inc., Fort Worth, TX, USA) with a low vacuum (250) and high cut-rate (5000–7500) is preferred. PFCL on posterior pole soon after PVD induction may further help in preventing macular injury. A thorough vitrectomy is done using wide-angle viewing system (Volk® miniquad XL), especially superiorly where a midline sclerotomy is planned between the superior ports. A 25G endoilluminator is inserted in one of the superior ports (e.g., superotemporal) depending on the dexterity of the surgeon. No leakage from ports was noted when a 25G chandelier endoilluminator was fixed through a 23G port. A 20G midline sclerotomy is then made using MVR at 12 o'clock after localized peritomy and hemostasis [Fig. 1a]. Intraocular magnet (IOM) is inserted from the midline sclerotomy, and FB stabilized with it. FB is finally freed from any residual vitreous with the cutter through the remaining superior port [Fig. 1b]. The FB is oriented along its least dimension [Fig. 1c] and extracted through midline sclerotomy under visualization. This can be done using IOM and intravitreal forceps bimanually. This helps to minimize the size of sclerotomy wound needed for extraction of FB. In case of anteriorly located FBs at pars plana [Fig. 2a], 25G endoilluminator is inserted in the port opposite to the site of FB impaction [Fig. 2b]. Midline sclerotomy is made, and an IOM or forceps is inserted [Fig. 2b]. Other port is plugged, and the sclera is indented simultaneous by the surgeon to localize the FB and aid in removal [Fig. 2b]. The FB is grasped/stabilized and later freed from surrounding vitreous as in the technique for intravitreal FB [Fig. 2c]. The FB is then removed through midline incision under direct visualization [Fig. 2d]. This method of extraction may rarely require augmentation using extraocular magnet. The sclerotomy and peritomy are then sutured with absorbable sutures. Retina is inspected intraoperatively to rule out any iatrogenic breaks and fluid-air-exchange done. The ports are then removed and left sutureless. Fig. 3a–d shows intraoperative photograph of a patient with intravitreal FB depicting various steps of the technique.

Figure 1

Schematic diagram depicting salient steps of the surgical technique and its advantages. (a) Schematic diagram showing the arrangement of ports and midline sclerotomy around the limbus. (b) Schematic diagram showing bimanual technique with endoilluminator to stabilize the foreign body with magnet and free it from surrounding vitreous with vitrectomy cutter. (c) Diagram showing modified handshake technique in midvitreous in the presence of chandelier endoilluminator to orient the foreign body along its long axis avoiding injury to lens and decreasing need for larger sclerotomy site. (d) Diagram shows handshake technique in anterior vitreous done directly under the microscope lead to increased risk of injury to lens in phakic patient

Figure 2

Intraoperative photograph showing the use of the bimanual technique with midline sclerotomy for anteriorly located foreign body (around pars plana region) in a phakic patient using 23G ports. (a) Scleral indentation and localization of pars plana foreign body. (b) Arrangement of ports and midline port/sclerotomy around the limbus. Bimanual technique to simultaneously indent (black arrow) and remove/stabilize the foreign body at pars plana using intravitreal forceps/magnet (white arrow). (c) Successful removal of pars plana foreign body under direct visualization without injury to crystalline lens. (d) Closure of midline sclerotomy site following successful removal of foreign body

Figure 3

Intraoperative photographs describing the technique of endoilluminator-assisted midline sclerotomy approach for intravitreal foreign bodies for phakic patients using 25G ports. (a) Photograph showing intravitreal foreign body (patient is phakic with clear lens). (b) After inserting endoilluminator (chandelier) in one of the ports, the foreign body is stabilized using intraocular magnet inserted via midline sclerotomy created after thorough superior vitrectomy. The foreign body is freed from surrounding vitreous using vitrectomy cutter from the remaining port. (c) Foreign body is oriented along its long axis in midvitreous cavity. (d) Foreign body is removed along its long axis through the sclerotomy site

Results

RIOFB removal was achieved in all four cases without complications such as slippage of foreign body, injury to retina, and lens. The results have been summarized in Table 1. All patients gained good visual acuity postoperatively without long-term complication such as cataract or retinal detachment.

Table 1

Summary of results using the midline sclerotomy approach for intraocular foreign body removal in phakic eyes using endoilluminator

Discussion

Bimanual stabilization of the FB with our technique using IOM and freeing it from surrounding vitreous with a cutter reduces risk of FB fall onto retina. Furthermore, as the midline sclerotomy is closer to the adjacent superior port, the handshake technique for orientation of FB to its least dimension can be done safely, without across the lens maneuvering avoiding inadvertent lens damage [Fig. 1d]. In case of anteriorly located FBs at pars plana, removal through external approach led to complications such as uveal incarceration and chamber instability. Even the removal of crystalline lens had been advocated before PPV to circumvent lens damage resulting in further struggle during FB removal. This technique helps in easy localization, stabilization, and removal of anteriorly located FB through pars plana route bimanually under direct visualization with the help of indentation.

Conclusion

With chandelier illumination, direct visualization of FB even in anterior vitreous cavity prevents the need for unwarranted sclerotomy wound extension, impaction of FB in wound, the requirement of extraocular magnet and multiple attempts for removal.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.