Use of an Iris Speculum for Retrolental Membrane Dissection for Stage 5 Prematurity of Retinopathy Complicated With Pupillary Adhesion : RETINA

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Surgical Technique

Use of an Iris Speculum for Retrolental Membrane Dissection for Stage 5 Prematurity of Retinopathy Complicated With Pupillary Adhesion

Lyu, Jiao PhD, MD; Zhang, Qi MD; Zhao, Peiquan PhD, MD

Editor(s): Williams, George A.

Author Information
Retina 43(1):p 138-143, January 2023. | DOI: 10.1097/IAE.0000000000002748

Abstract

In stage 5 retinopathy of prematurity (ROP), tractional components at the fibrovascular ridge contract circumferentially and detach the retina anteriorly, folding the peripheral avascular retina into a ridge-to-ora serrata trough.1–4 In more severe cases, a pupil-traversing retrolental membrane seals the trough and firmly adheres to the periphery of the anteriorly detached retina behind the lens.5,6 A limbal-based closed vitrectomy provides access to the retrolental membrane without the risk of subretinal instrumentation entry. Complete dissection of the retrolental membrane from periphery to center can simultaneously interrupt the peripheral trough and release epiretinal traction, which may maximally facilitate retinal reattachment.2,5,7,8 However, excessive inflammation and contractile retrolental tissue induce inadequate mydriasis, pupillary adhesion, and bulging of the iris–lens diaphragm.2,5,6 With poor pupillary visualization and restricted retrolental space, technical difficulties prevent satisfactory delamination of extensive adhesion in the peripheral trough during a closed vitrectomy.2,9,10 Extensive or sectional iridectomy combined with iris hooks was routinely performed to maximize the size of the pupil and to prevent postoperative reproliferation along the posterior iris surface.2,5,8,11 However, aggressive management of the iris leads to intensive inflammation and a permanently oversized pupil, which undermines anatomical improvement and patients' cosmetic appearance.

The Xpand NT iris speculum (Diamatrix Ltd, Woodlands, TX) was previously used for pupillary expansion and iris stabilization during cataract surgery.12 It is a delicate 6.75-mm ring with eight arches.12 Here, we describe an innovative use of the device to assist in membrane dissection along the peripheral trough in limbal-based closed vitrectomy for stage 5 ROP complicated with pupillary adhesion. The device effectively improves surgical visualization during along-the-trough retrolental membrane dissection and preserves pupillary configuration.

Methods

Techniques

(Figure 1; see Video, Supplemental Digital Content 1, https://links.lww.com/IAE/B168).

F1
Fig. 1.:
Use of iris speculum in limbal-based closed vitrectomy and along-the-trough dissection of retrolental membrane in the left eye of patient 9 with stage 5 ROP and a funnel-shaped TRD. A. The eye showed posterior synechiae and a shallow anterior chamber. B. After synechiolysis and lensectomy, the X-pand NT iris speculum was folded into the injector tube. C. The anterior chamber was inflated with viscoelastic. The iris speculum was advanced into the anterior chamber from the injector via a superior 3.0-mm corneal incision. The iris speculum was placed on the pupillary rim with narrow arches upward. The pupil was enlarged, and the iris plane was stabilized to a neutral position. The retrolental membrane proximal to the ciliary process was exposed (hollow arrow). D. The trough was obscured underlying the retrolental membrane. An opening cut was selected at the edge of retrolental membrane proximal to the ciliary process. E and F. Bimanual dissection along the trough was performed circumferentially by 20 G end-gripping forceps in one hand and 20-G vertical scissors in the other hand. Firm adhesion on ridge was also removed. Exposure of the surgical field beneath the pupil and in the trough was maximized. G. The trough (anterior to the yellow line) was separated, and forces on retina were maximally released. H. The speculum was positioned on the iris speculum and then taken out by the injector. I. At the end of the surgery, the retinal funnel was unraveled, and pupil configuration was preserved. ROP, retinopathy of prematurity; TDR, tractional retinal detachment.

Closed vitrectomy and retrolental membrane dissection were performed via a limbus approach. Pupillary adhesion to the endothelium and/or posterior synechiae was delaminated with viscoelastic. Limited iridectomy was performed by inserting a 23-G vitreous cutter into the pupillary margin (0.5 mm) to address any contractile fibrosis. A 20-G anterior chamber infusion line was created via the temporal limbal entry. After synechiolysis, 23-G lensectomy was performed in phakic eyes.

The anterior chamber and the retroiris space were inflated with viscoelastic. The X-pand NT iris speculum was mounted in an injector which was then inserted via a superior 3.0-mm corneal incision into the anterior chamber. The iris speculum was slowly advanced from the injector tube with its distal arch placed at the inferior pupillary rim, followed by positioning of the lateral arches and the proximal arch on the superior pupillary rim. A specific manipulator was used to help position the arches, if indicated. Narrow arches were oriented upward to clear a pathway for instrument insertion. Downward-facing wide arches anchored the posterior iris surface to provide space for retrolental dissection. The pupil was expanded to achieve an octagonal shape, and the iris plane was stabilized at a neutral position. The peripheral membrane over the trough proximal to the ciliary process was exposed, with the globe rotated in the intended direction.

Circumferential bimanual membrane dissection proceeded toward the anterior retina with 20-G end-gripping forceps (TITAN; Titan Surgical LLC, Kazan, Russia) in one limbal entry lifting the membrane over the peripheral trough and 20-G vertical scissors (TITAN) at the opposite entry site for incision and along-the-trough dissection, within the retrolental space spared by the iris speculum. An invisible trough overlying an opaque and pupil-traversing membrane was explored from the edge of the membrane, proximal to the ciliary process. The blades of vertical scissors were slid into the trough, parallel to the underlying retina plateau, toward the gently lifted membrane in the space beneath the iris speculum. Then, the retrolental membrane was circumferentially delaminated to the center and entirely resected. Epiretinal fibrosis and condensed vitreous sheets were then trimmed. The vitreous cavity and anterior chamber were filled with viscoelastic to expand the retinal funnel and maintain intraocular pressure. The iris speculum was positioned on the iris surface with a manipulator and taken out from the anterior chamber with the injector. Limbal incisions were sutured with 10-0 nylon.

Results

Ten eyes from 9 preterm infants with stage 5 ROP and pupillary adhesion underwent limbus-based closed vitrectomy and retrolental membrane dissection between October 2017 and October 2018 (Table 1). The iris speculum was manipulated smoothly in all eyes without causing iridodialysis or a sphincter tear. The median duration of surgery was 41 minutes. Pupillary expansion and the iris plane were stable, without dislocation or movement of the iris speculum. Retrolental membrane dissection along the trough was performed uneventfully in all eyes.

Table 1. - Surgical Outcomes of Patients With Stage 5 ROP-Related TRD and Inadequate Mydriasis
Pt Gender GA, week BW, g Eye Preoperative Peroperative Postoperative
TRD* Trough Pupil Other Features Previous Treatment Adjuste-d Age at Surgery, Month Surgery Time of Surgery, minutes Fundus Pupil Vision Follow-up, Month
1 Girl 28 1,005 OD A/A Wide, shallow Secluded pupil Corneal leukocoria, phakia, flat anterior chamber / 5 V/L/M 30 Expanded Deformation NA 14
2 Girl 31 1,600 OD A/A Wide, deep Secluded pupil Corneal leukocoria, white cataract, flat anterior chamber IVR 22 V/L/M 40 Partially attached posterior pole Circular LP 15
3 Boy 30 1,250 OS A/A Wide, deep Secluded pupil Phakia, flat anterior chamber / 12 V/L/M 37 Partially attached Circular LP 18
4 Girl 29 1,450 OS O/A Narrow, shallow Posterior synechia Phakia Laser 5 V/L/M 42 Partially attached posterior pole Circular LP 8
5 Boy 29 1,250 OS A/A Wide, shallow Posterior synechia Phakia, flat anterior chamber / 7 V/L/M 48 Partially attached posterior pole Circular FF 6
6 Boy 28 1,200 OS A/A Wide, deep Posterior synechia Phakia, flat anterior chamber / 6 V/L/M 41 Attached macular and posterior pole Circular NA 6
7 Boy 25 560 OD O/A Wide, shallow Posterior synechia Aphakia due to a prior closed vitrectomy Laser, V/L 8 V/M 45 Partially attached Circular NA 6
OS O/A Wide, shallow Posterior synechia Aphakia due to a prior closed vitrectomy Laser, V/L 9 V/M 37 Partially attached posterior pole Circular NA 6
8 Boy 29 1,000 OD A/A Wide, deep Posterior synechia Phakia, shallow anterior chamber / 9 V/L/M 49 Attached macular and posterior pole Circular FF 6
9 Boy 27 870 OS A/A Wide, deep Posterior synechia Phakia / 10 V/L/M 45 Attached macular and posterior pole Circular NA 6
*The anterior and posterior configuration of the funnel-shaped retinal detachment was also based on the International Classification of ROP.4
A/A, narrow/narrow; CF, counting fingers; FF, fix and follow; GA, gestational age; IVR, intravitreal injection of ranibizumab; L, lensectomy; LP, light perception; M, membrane peeling; NA, not available; O/A, open/narrow; ROP, retinopathy of prematurity; TRD, tractional retinal detachment; V, vitrectomy.

After 6 to 18 months of follow-up, 9 of 10 eyes showed partial retinal reattachment; 4 eyes had partial attachment of posterior pole, and 3 eyes had a flat posterior pole and macula. As for postoperative pupil configuration, 9 eyes with retinal reattachment had circular pupils without adhesion (Figure 2). In one eye with narrow–narrow tractional retinal detachment, the funnel of detached retina had expanded. The eye had a pupil deformation superiorly. Anterior chamber depth was normal in all eyes. Improved corneal transparency was observed in all two eyes with preexisting corneal opacity. The visual testing available for these five infants demonstrated visual perception.

F2
Fig. 2.:
Postoperative examinations on 3 months with RetCam imaging. A. Posterior retina attachment. B. A round pupil without posterior synechiae.

Discussion

Previously, periphery-to-center membrane dissection during “open-sky” vitrectomy was believed to sufficiently remove anterior fibrovascular proliferation for the repair of stage 5 ROP.7,8 In a closed vitrectomy, satisfactory separation of the peripheral trough adhesion demands sufficient exposure of the surgical field for meticulous exploration of the epiretinal space proximal to the ciliary process.2,9,10 Extensive iridectomy to manage pupillary adhesion and widen surgical visualization is invasive when performed in pediatric eyes. Iris hooks pinch out a square-shaped pupil, which is suboptimal for peripheral visualization and traumatic to the iris.13 In addition, multiple external shafts of iris hooks clutter the surgical field and interfere with instrumentation.

The X-pand NT iris speculum is fashioned with a memory nitinol wire. It possesses good elasticity and resistance for stable pupil expansion and nice flexibility for gentle manipulation in fragile pediatric eyes. Its eight arches evenly enlarge the pupillary rim to a wide, near-circular shape.12 For stage 5 ROP with pupillary adhesion, meticulous synechiolysis and use of the iris speculum sufficiently expose the circumferential surgical field proximal to the ciliary process during membrane dissection via limbal closed vitrectomy. In the cases described previously, in contrast to routine usage, the narrow arches of the iris speculum were placed upward. This important modification was tailored for limbal closed vitrectomy to reduce the chances of interference with the instrument's entry. A Malyugin ring (MicroSurgical Technology, Redmond, WA), a polypropylene pupil expansion ring, allows for the standardization of pupil expansion in cataract and vitreoretinal surgery. The limitations of this tool include increased risk of ring deformation, fracture, and dislocation during manipulation (because of its soft nature).14

Furthermore, use of the X-pand NT iris speculum stabilizes the iris plane to ease trough membrane dissection. After the separation of pupillary adhesions, the iris, free of strain, readily prolapses or becomes caught during instrument entry and manipulation. The resulting lack of lens support often gives rise to iris retropulsion during membrane dissection. In the current series, the iris speculum tightly cradled the pupillary rim and maintained the iris plane in a neutral position. The approach creates a surgical pathway extending from the anterior chamber to the retrolental space. In situ membrane dissection along the trough is feasible beneath the pupillary rim and does not require central lifting of the peripheral membrane for dissection. Notably, excessive traction on the peripheral avascular retina frequently leads to retinal dialysis or tear.7 Iatrogenic retinal breaks are not rare, especially when outside-in dissection is performed in a relatively shallow and narrow trough.8 We therefore used angled vertical scissors to circumferentially slide along the trough, rather than using blade-forward curved scissors, which are suboptimal for creating a safe and large cut along the trough. Use of the current method in combination with closed vitrectomy allows for sufficient removal of anterior fibrotic vectors and thus encourages retinal reattachment, prevents the recurrence of posterior synechiae, and preserves the circular configuration of the pupil.

Issues pertaining to the technique require attention. If the iris speculum cannot be entirely folded into the injector tube for insertion and removal, manipulation aided by microforceps or vitreoretinal forceps is feasible. The peripheral trough can also be explored after radial expansion of the central membrane through creation of a cut that extends to the periphery, although the risk of penetrating centrally detached retina increases. This technique was not used to address “crunching” retinal detachment in patients with aggressive posterior ROP after the use of anti–vascular endothelial growth factor drugs.15 We did not use 25- or 27-G instruments because they may not adequately address firm adhesions and robust tissue.

In conclusion, the use of an iris speculum optimizes retrolental membrane dissection in closed vitrectomy for stage 5 ROP-related tractional retinal detachment complicated with pupillary adhesion. This surgical method allows for dissection of the entire peripheral trough and retrolental membrane, which sufficiently releases tractional vectors. This technique maximally preserves the configuration of the pupil and prevents the recurrence of posterior synechiae.

References

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Keywords:

pupil expander; membrane; retinopathy of prematurity; vitrectomy

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