Issue link: http://retinalphysician.epubxp.com/i/783300
Forceps designed for foreign body removal, such as Rappazzo forceps and straight forceps, can be used to remove the IOFB. For smaller IOFBs, 23-gauge serrated or MAXgrip forceps may be used. For very small IOFBs, aspiration can be performed with a soft cannula or the vitrector. Removal of fishhook IOFBs (Figure 7) in the cornea and anterior cham- ber can be challenging. Depending on the size of the hook and the presence of barbs, techniques such as the back-out, advance-and-cut, and cut-and-push-through can be used to minimize anterior ocular damage. 14 Lenticular IOFBs When dealing with a lenticular IOFB it is essential to evalu- ate the features of the lens that can help direct the approach. A pars plana approach lensectomy and vitrectomy for lens removal is preferred if the posterior capsule is violated or if there is marked lens instability/zonular dialysis. Otherwise, IOFB removal with phacoemulsification can be per- formed without a concurrent vitrectomy. Due to increased risk of endophthalmitis with primary IOL placement, the authors recommend leaving the patient aphakic initially. 15 Additionally, lens calculations may be inaccurate due to the surgeon's inability to correctly perform axial length and kera- tometry measurements at the time of an OGI. Posterior Segment IOFBs e most common approach for a posterior segment IOFB is a pars plana vitrectomy and removal through either a scleral or corneal wound. e standard three-port set-up is used. If there are media or lenticular opacities obscuring the view or a choroidal detachment, a 6-mm infusion or an anterior cham- ber maintainer can be used. e gauge size is based on the surgeon's preference. e first step is to remove the vitreous to allow for manipu- lation of the IOFB without causing vitreous traction. Posterior vitreous detachment (PVD) induction in these patients may be difficult due to the young age of most patients. Intravitreal diluted Kenalog or Triesence may be helpful when inducing a PVD. After the vitreous is meticulously removed, attention can be directed toward the IOFB removal. e plan for IOFB removal should be made prior to manipulating the IOFB. Cases with concurrent significant lens trauma, which require lensectomy, are good candidates for IOFB removal through the cornea. If the IOFB is not too large, a corneal limbus wound can be made to remove it. If the IOFB is very large, a scleral tunnel can be considered. Use viscoelastic to protect the corneal endothelium prior to removal of the IOFB through the cornea. In cases with an uninvolved lens or minimal focal changes, the lens can be preserved. Such patients are good candidates for removal through an existing sclerotomy or a separate pars plana sclerotomy. Preplaced sutures in large sclerotomy wounds may facilitate quick intraocular pressure stabilization and prevent complications, such as choroidal detachment or expulsion of intraocular contents after the IOFB is removed. After creating the wound for removal, attention can be directed toward removal of the IOFB. IOFBs may develop overlying inflammatory membranes or scar tissue that need to be removed with forceps prior to manipulating the IOFB. A range of instruments can be used to then grasp the IOFB and remove it through the wound. Options include multiple disposable forceps and reusable forceps, such as the diamond- dusted Wilson, Machemer, basket, and Rappazzo forceps. For very round IOFBs, such as a BB pellet, specific reusable and disposable BB pellet forceps are available. If those instru- ments are not available, the Alcon loop scraper can be used as a snare for small foreign bodies. If the foreign body is very large, a snare can be fashioned by passing a loop of Prolene suture through a blunt needle attached to a TB syringe, with the ends of the suture exiting the syringe. Moving the plunger of the syringe up and down will enlarge and tighten the snare. A 0.12-gauge forceps can be used when removing the foreign body to help open the wound more widely. A bimanual technique also can be employed to remove the IOFB. In phakic patients this requires chandelier illu- mination. e IOFB can be grasped and elevated with one instrument that can safely elevate the IOFB but not easily remove it (eg, an intraocular magnet or backflush cannula). After elevation, it can be grasped by one of the aforemen- tioned forceps and removed. In aphakic or pseudophakic patients, an alternative method is to use the initial instrument 51 R E T I N A L P H Y S I C I A N . C O M | J A N U A R Y / F E B R U A R Y 2 0 1 7 Figure 6. Axial computed tomography scan indicating poste- rior intraocular foreign body in the eye. Figure 7. Photo demonstrating fish hook foreign body tra- versing the cornea into the anterior chamber.