Intraoperative optical coherence tomography in the full-thickness macular hole surgery with internal limiting membrane inverted flap placement

The State of Intraoperative OCT in Vitreoretinal Surgery: Recent Advances and Future Challenges

Since its first introduction more than 30 years ago, optical coherence tomography (OCT) has revolutionized ophthalmology practice, providing a non-invasive in vivo cross-sectional view of the structures of the eye. Mostly employed in the clinical setting due to its tabletop configuration requiring an upright patient positioning, the recent advent of microscope-integrated systems now allows ophthalmologists to perform real-time intraoperative OCT (iOCT) during vitreoretinal surgical procedures. Numerous studies described various applications of this tool, such as offering surgeons feedback on tissue-instrument interactions in membrane peeling, providing structural images in macular hole repair, and showing residual subretinal fluid or perfluorocarbon in retinal detachment surgery. This narrative review aims at describing the state of the art of iOCT in vitreoretinal procedures, highlighting its modern role and applications in posterior segment surgery, its current limitations, and the future perspectives that may improve the widespread adoption of this technology.

Inverted ILM Flap Technique in Idiopathic Full-Thickness Macular Hole Surgery: Functional Outcomes and Their Correlation with Morphologic Findings

Objectives

The inverted internal limiting membrane (ILM) flap technique has been shown to increase the success rate in large full-thickness macular holes (FTMHs) and in FTMHs associated with high myopia. The aim of our study was to confirm the efficacy and safety of inverted ILM flap technique in idiopathic FTMHs independent of their dimensions and to assess functional outcomes and their correlation to morphologic findings.

Methods

Sixteen consecutive patients affected by idiopathic FTMH were enrolled in this prospective study. The preoperative mean (±SD) diameter of the FTMH was 422 (±106) µm. All patients underwent vitrectomy and ILM peeling with inverted ILM flap. At 1-, 3-, and 6-month postoperative visits, visual acuity measurement, indirect ophthalmoscopy, and microperimetry were performed, and the foveal contour and the integrity of the ellipsoid zone (EZ) and external limiting membrane (ELM) were investigated using spectral domain optical coherence tomography (SD-OCT).

Results

At six months postoperatively, 15 out of 16 (93.75%) patients obtained FTMH closure. The mean best corrected visual acuity (BCVA) improved from 1.1 LogMAR to 0.3 LogMAR, and the mean retinal sensitivity (MS) improved from 7.2 to 23.4 dB. ELM defects were evident in 1 out of 16 (6.25%) eyes, and EZ defects were detected in 2 out of 16 (12,50%) eyes. A statistically significant relationship was observed between BCVA, MS, and EZ reconstitution at each follow-up visit.

Conclusions

Results confirm that the inverted ILM flap technique is a safe and effective option for FTMH treatment and show a strong correlation between higher BCVAs and MSs and EZ reconstitution after surgery.

Inverted internal limiting membrane flap technique in eyes with large idiopathic full-thickness macular hole: long-term functional and morphological outcomes

Purpose

To investigate morphological and functional outcomes of the inverted internal limiting membrane (I-ILM) flap technique in large (≥ 400 μm) idiopathic full-thickness macular holes (FTMH) over a follow-up period of 12 months.

Methods

In this retrospective study, 55 eyes of 54 consecutive patients were enrolled. Best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT, Heidelberg, Spectralis) were performed preoperatively as well as 1, 3, 6, 9, and 12 months postoperatively. Special focus was put on the reintegration of outer retinal layers and the different ILM flap appearances.

Results

FTMH closure rate was 100% (55/55). BCVA significantly improved over the follow-up period of 12 months from 0.98 ± 0.38 LogMAR preoperatively to 0.42 ± 0.33 LogMAR at 12 months postoperatively (p < 0.001). There was no significant correlation between the three different ILM flap appearances and BCVA. Better preoperative BCVA, complete restoration of the external limiting membrane (ELM), higher macular hole index (MHI), and smaller MH base diameter were associated with higher improvement of BCVA.

Conclusion

Our study highlights the favorable morphological and functional outcomes of the I-ILM flap technique in the short as well as in the long term. While complete ELM restoration revealed to be an important factor for improvement in BCVA, the different postoperative ILM flap appearances seem not to be related to BCVA.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05082-7.

Intraoperative Optical Coherence Tomography Guided Ocular Surgeries: Critical Analysis of Clinical Role and Future Perspectives

Intraoperative imaging of ocular tissues for diagnostic and therapeutic applications has gained immense admiration in recent years. The real time cross-sectional imaging, as well as three and four dimensional reconstruction abilities of intraoperative optical coherence tomography (iOCT), has enhanced our knowledge on many fronts in surgical maneuvers. In this review, we discuss the iOCT discovered constructive knowledge in the cornea, cataract, refractive, glaucoma, pediatric ocular, and various retinal conditions. The practical utility with decision modifying aspects along the specified ocular tissues and with respect to specific ocular entities have been narrated. Moreover, limitations and future directions have also been emphasized to make ophthalmic care more comprehensive in the future.

Macular hole edge morphology predicts restoration of postoperative retinal microstructure and functional outcome

Background

To investigate the ability of intraoperative optical coherence tomography (iOCT) during macular hole (MH) surgery to image different hole edge configurations and predict the restoration of retinal microstructure and visual outcomes.

Methods

This retrospective case series study included 53 MH patients. One eye each was assessed with iOCT during vitrectomy after internal limiting membrane (ILM) peeling. The MHs were categorized into three groups according to the morphology of the hole edge. The Hole-Door group had vertical pillars of tissue that projected into the vitreous cavity after ILM peeling. The Foveal Flap group had a preoperative foveal flap that adhered to the hole edge after ILM peeling, and the Negative group had neither a hole-door nor a foveal flap. At 6 months after surgery, the retinal microstructure restoration and visual outcomes were compared among the groups.

Results

All eyes had MH closure, and the postoperative best corrected visual acuity (BCVA) was significantly improved compared with the preoperative BCVA (P < 0.001). The Hole-Door group (n = 15) and Foveal Flap group (n = 14) had significantly better final visual acuity and postoperative restoration of the external limiting membrane (ELM) than the Negative group (n = 24) (P = 0.002, P = 0.012). For the group in which the MH diameter (MHD) was ≤400 μm (n = 25), there were no significant differences in ELM restoration, ellipsoid zone (EZ) restoration, or BCVA among the three groups (P = 0.516, P = 0.179, and P = 0.179 respectively). For the MHD > 400-μm group (n = 28, the Hole-Door group and Foveal Flap group had significantly better final visual acuity and restoration of ELM than the Negative group (P = 0.013, P = 0.005).

Conclusions

The novel use of iOCT during MH surgery confirmed the presence of hole edges configured as door-holes, foveal flaps, or neither. The data acquired by iOCT can provide useful predictive information for postoperative restoration of the retinal microstructure and visual outcome of MH, especially large ones.

What Is the Impact of Intraoperative Microscope-Integrated OCT in Ophthalmic Surgery? Relevant Applications and Outcomes. A Systematic Review

Background: Optical coherence tomography (OCT) has recently been introduced in the operating theatre. The aim of this review is to present the actual role of microscope-integrated optical coherence tomography (MI-OCT) in ophthalmology. Method: A total of 314 studies were identified, following a literature search adhering to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. After full-text evaluation, 81 studies discussing MI-OCT applications in ophthalmology were included. Results: At present, three microscope-integrated optical coherence tomography systems are commercially available. MI-OCT can help anterior and posterior segment surgeons in the decision-making process, providing direct visualization of anatomic planes before and after surgical manoeuvres, assisting in complex cases, and detecting or confirming intraoperative complications. Applications range from corneal transplant to macular surgery, including cataract surgery, glaucoma surgery, paediatric examination, proliferative diabetic retinopathy surgery, and retinal detachment surgery. Conclusion: The use of MI-OCT in ophthalmic surgery is becoming increasingly prevalent and has been applied in almost all procedures. However, there are still limitations to be overcome and the technology involved remains difficult to access and use.

Dynamic intraoperative optical coherence tomography for inverted internal limiting membrane flap technique in large macular hole surgery

BACKGROUND/OBJECTIVES

To assess the efficacy of dynamic intraoperative spectral-domain optical coherence tomography (iSD-OCT) imaging for inverted internal limiting membrane (ILM) flap technique (IILMFT) in large macular hole (MH) surgery.

SUBJECTS/METHODS

Prospective, non-randomized, observational study was conducted on 8 eyes of 7 patients with large, chronic and recurrent MHs, which were treated by pars plana vitrectomy (PPV) with IILMFT. All patients underwent standard pre- and postoperative examination. The iSD-OCT imaging was performed using microscope integrated systems before, during, and after ILM peeling. The iSD-OCT data were post-processed using graphic software and reviewed for tissue behavior and instruments position.

RESULTS

The real-time iSD-OCT-assisted IILMFT allowed for real-time imaging of the entire surgery with visualization of the MH, vitreoretinal instruments, and all steps of inverted ILM flap formation. In spite of shadowing created by the steel instruments, it was possible to follow and control the distance between the instrument tips and retinal layers. Dynamic imaging of the surgical maneuvers including ILM peeling and mechanical apposition of MH edges revealed the iatrogenic impact on the retina (depression and appearance of hyporeflective zones). iSD-OCT imaging could confirm the proper position of the inverted ILM flap at the very end of the surgery after fluid-air exchange.

CONCLUSIONS

iSD-OCT imaging is an effective tool for learning and performing a well-controlled and safe inverted ILM flap technique in patients with large MH. Clinical significance of the structural iSD-OCT findings has to be further studied.

Surgical management of diabetic tractional retinal detachments

Tractional retinal detachment is an end-stage form of diabetic retinopathy that occurs when contractile forces in the vitreous and neovascular tissue lead to the detachment of the neurosensory retina. We review the literature related to the management of this disease. Preoperative planning includes appropriate patient selection, diagnostic and prognostic imaging, and medical optimization with reduction of systemic risk factors. Use of antivascular endothelial growth factor for preoperative treatment has had significant benefits for tractional retinal detachment repair in improving surgical efficiency and outcomes. Advances in microsurgical instrumentation are discussed, with attention to small-gauge vitrectomy with improved flow dynamics, viewing strategies, and lighting allowing bimanual surgery. Special emphasis is placed on bimanual surgical technique, choice of tamponade, and the avoidance of iatrogenic damage. Complications and special considerations are further explored. Based on our compilation of relevant literature, we propose a surgical algorithm for the management of these complex patients.

Inner Retinal Layer and Outer Retinal Layer Findings after Macular Hole Surgery Assessed by means of Optical Coherence Tomography

Aim

To summarize the spectrum of optical coherence tomography (OCT) and OCT angiography (OCTA) features after full-thickness macular hole (MH) repair surgery.

Methods

A PubMed engine search was carried out using the terms "Macular Hole," "Optical Coherence Tomography," and "Optical Coherence Tomography Angiography." All reports published in English up to October 2018, irrespective of their publication status, were included. Tomographic signs analyzed were divided according to the involved portion of the retina in "inner retinal layers" and "external retinal layers." Despite predominantly involving the inner retinal layers, cystoid macular edema (CME) has been treated as a separate entity. Finally, report on vessel density (VD) changes and the foveal avascular zone (FAZ) area modifications have been included.

Results

Different clinical findings can be observed on OCT of patients who underwent MH repair surgery. There is general consent that retinal thinning involving primarily the retinal nerve fiber layer and the ganglion cell layer takes place after surgery. In the postoperative period, the outermost retinal layers get progressively restored. Persistent defects in the ellipsoid zone or in the external limiting membrane correlate with worse postoperative visual outcome. OCTA has globally demonstrated that eyes after MH closure show a reduction in macular and paramacular VD and smaller FAZ areas, compared with control or fellow eyes.

Conclusion

Clinicians should be aware of the most common tomographic findings to properly manage each condition. In addition, significant advantages for the postoperative application of OCT and OCTA include noninvasiveness, rapid and simple execution, repeatability, and precise measurements.