T-shaped sclerotomy as the preferred approach for removing large intraocular foreign bodies: a case report

Ocular trauma is among the leading causes of vision loss globally. As reported by the World Health Organization, approximately 55 million eyeball injuries occur each year, leading to limitations in daily activities for more than 1 day [1]. Therefore, it is essential to manage the injury promptly and appropriately. A penetrating injury with an intraocular foreign body (IOFB) compromises the integrity of the eyeball and is considered a medical emergency. An IOFB can become embedded in any part of the eyeball, and 23-gauge (G) standard pars plana vitrectomy (PPV) constitutes the treatment of choice for cases with IOFBs positioned in the posterior segment of the eyeball [2‐4]. We present the case of a patient who sustained a penetrating ocular injury with a large (> 5 mm) retained metallic IOFB located in the posterior segment of the eyeball, which was successfully removed through a modified scleral approach (T-shaped sclerotomy) during a 23‑G PPV.

A 69-year-old systemically healthy male patient presented to our department with complaints of sudden, painful vision loss, sensitivity to ambient light, and inability to open the right eye (OD), which was due to a workplace-related injury with a sharp metallic object while operating a saw machine. When specifically questioned, he denied experiencing any seizures; loss of consciousness; headache; or bleeding from the nose, throat, or ears following the injury. The patient also denied any previous incidents of eyeball injuries and reported a surgical history of cataract surgeries performed 3 years earlier. Upon admission his best-corrected visual acuity (BCVA) was 20/200 in the OD and 20/20 in the left eye (OS). External inspection demonstrated a full-thickness vertical tear in the middle of the right upper lid. Slit-lamp biomicroscopy revealed conjunctival congestion, full-thickness scleral tear extending horizontally from the 12:00- to 12:30-o’clock position approximately 1 mm in length (the edges of the tear showed no signs of an impacted foreign body or vitreous strings), intact cornea, deep anterior chamber with hyphema, and intraocular lens (IOL) in its place. The biomicroscopic fundus examination did not reveal any details, but the red reflex was present. The OD intraocular pressure (IOP) was 8 mm Hg, measured with a noncontact tonometer. B‑scan ultrasonography (USG), performed extremely gently, showed vitreous hemorrhage with a tract-like membrane extending posteriorly and a hyperechoic mobile-appearing opacity with acoustic shadowing lying over the retina, highly suggestive of a metallic IOFB (Fig. 1). There was no evidence of retinal or choroidal detachment. X‑ray and CT imaging of the orbits revealed one large retained metallic IOFB located in the inferior aspect of the right eyeball (Fig. 1). According to the Ocular Trauma Score (OTS), the injury was classified as Type C, Grade D, and Zone 3. After obtaining written informed consent, the IOFB measuring 4.5 × 3 × 7 mm was successfully removed with forceps using a T-shaped pars plana scleral incision technique, during 23‑G PPV.

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The primary lid tear and the entry wound of the OD were sutured using absorbable stitches. Subsequently, the patient underwent three-port, 23‑G standard PPV with core and peripheral vitrectomy. Triamcinolone was utilized as a visual aid, and after this step 1 cm³ of perfluorocarbon liquid (PFCL) was administered for posterior pole coverage to preserve the macula from potential damage resulting from dropping the IOFB [5]. Subsequently, a T-shaped sclerotomy was performed using a trocar knife, with a supplementary perpendicular radial incision made at the center of the previous sclerotomy and directed toward the limbus in the following manner:

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At the 2‑month follow-up, the BCVA of the OD was 20/70 with an IOP of 13 mm Hg. The patient was pseudophakic with an attached retina. There were no intraoperative or postoperative complications.

Ocular trauma is among the leading causes of vision loss worldwide. A penetrating ocular trauma with the presence of a retained IOFB is the most common avoidable cause of posttraumatic unilateral blindness or low vision [1]. It predominantly affects males in the working-age population at their workplace (86.7%; [2]). The severity of an ocular injury from an IOFB is influenced by its mass, speed, dimensions, characteristics, point of entry, and the degree of impaction [7, 8]. Metallic IOFBs are the most frequently encountered IOFB [9]; they exhibit long-term toxicity and can lead to ocular siderosis [10, 11]. When diagnosing IOFBs, orbital imaging plays a pivotal role. Magnetic resonance imaging (MRI) should be postponed until metallic IOFBs have been ruled out [12]. Computed tomography is considered the gold standard for identifying metallic IOFBs. It determines the quantity, shape, dimensions, and configuration of an IOFB and provides details regarding its positioning (intraocular or extraocular), with a sensitivity of 100% for IOFBs > 0.06 mm³ [13]. With the help of clinical examination and imaging, it is possible to choose an optimal sclerotomy location through which the IOFB will be removed. In cases involving larger IOFBs, it is necessary to extend or to perform additional sclerotomies [14]. Long sclerotomies aligned parallel to the corneal limbus may lead to intraoperative complications and may be associated with IOP instability, wound bleeding, and difficulty in visualizing the operating field. Postoperative complications include choroidal detachment, bleeding and leakage from the wound, conjunctival blistering, and increased astigmatism that contribute to worse visual outcomes [15, 16]. It follows that postoperative outcomes depend not only on the ocular damage caused by the injury itself, but also on potential iatrogenic injuries that may occur through surgical interventions, as well as on postsurgical complications [2]. Prior to broad implementation of 23‑G standard PPV, which constitutes the current treatment of choice for large retained metallic IOFBs in the posterior segment, these foreign bodies were removed through the corneal or scleral wound using external electromagnets. Such uncontrolled removal led to iatrogenic damage in 43% of cases, resulting in intra- and postoperative complications [17]. Mester and Kuhn compared the use of an external magnet versus PPV with forceps extraction, finding that eyes treated with forceps and PPV for IOFB removal had better anatomical and functional outcomes [17]. Currently, advanced intraocular surgical methods have significantly improved the outcomes for patients suffering from ocular trauma. Apart from the type of tool used to grasp an IOFB, an incorrectly sized or shaped incision can lead to the IOFB falling onto the retina. Therefore, it is essential to properly modify the sclerotomy design to facilitate surgical maneuvers, depending on the size of IOFB [2]. A modified sclerotomy of appropriate dimensions, incorporating a supplementary 1.5-mm perpendicular incision (T-shaped sclerotomy) in the direction of the limbus, provides a larger surgical manipulation area despite shorter incisions. This modified incision technique with its design and two cuts can expand the range of IOFB sizes that can be removed without elevating the risk of iatrogenic injuries, such as an IOFB falling onto the retina, or harming other surrounding ocular tissues [2]. Therefore, the ideal T‑shaped sclerotomy needs to be made in the most peripheral area of the pars plana region. The farther the horizontal incision is placed toward the periphery, the less distortion will be caused to the cornea. Since scleral scar tissue contracts along the horizontal axis, an additional perpendicular incision appears to have little impact on postoperative corneal astigmatism [2, 18]. The length of the perpendicular incision should be restricted to the extent of the pars plana, typically between 1.5 and 4 mm from the limbus in eyeballs with an average axial length [2]. Results of a retrospective, single-arm, interventional study of a series of patients diagnosed with open globe injury (according to Birmingham Eye Trauma Terminology) who underwent 23‑G PPV with a T-shaped sclerotomy, incorporating a supplementary 1.5-mm radial incision to remove IOFBs, performed by Toro et al. [2], are not in agreement with earlier research, in which IOFBs were considered to be one of the most significant contributors to poor postoperative visual acuity (VA; [8, 15]). Poor postoperative VA as a consequence of removing of IOFBs through the corneal approach, particularly when the wound is much smaller than the maximum diameter of the IOFB (because of its rotation), results in poor wound healing, progressive loss of corneal endothelial cells, and increased irregular corneal astigmatism. To prevent these complications, limbus-parallel or scleral approaches are recommended during PPV procedures for cases with large IOFBs retained in the posterior segment of the eye. T‑shaped sclerotomy due to the use of two incisions increases the extraction area ([4]; Fig. 3). At the same time, the healing surface of the wound is significantly larger compared to other straight designs. This results in reduced postoperative wound shifting and promotes faster visual rehabilitation. Spearman’s rank correlation coefficient analysis of 30 patients included in the study showed that the largest diameter (length) of an IOFB had no effect on visual outcomes at the 6‑month follow-up. Additionally, there was no correlation between the size of the IOFB and IOP, either before surgery or during postoperative visits (1 day and 6 months after surgery). Furthermore, it proved to be a safe technique, as no iatrogenic lesions or increased intra- and/or postsurgical complications were observed [2].

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T‑shaped sclerotomy, incorporating a supplementary 1.5-mm radial incision in the pars plana region toward the limbus during 23‑G PPV, appears to be effective and very safe and can be considered the preferred approach for removing large and retained IOFBs from the posterior segment. This modification needs to be validated in a larger cohort of patients before it is established as the approach of choice for patients presenting with large IOFBs.