Iatrogenic retinal traumas in ophthalmic surgery

Safety and feasibility of sutureless pars-plana vitrectomy in sub-Tenon anesthesia (SAFE-VISA): a prospective study

BACKGROUND

To determine the safety and feasibility of sutureless pars-plana vitrectomy (ppV) in sub-Tenon anesthesia.

METHODS

In this prospective study. Pain and anxiety at various times after ppV using a visual analogue scale (VAS) and Wong-Baker-FACES scale as well as visual sensations during surgery were investigated. The surgeon evaluated motility, chemosis, overall feasibility.

RESULTS

ppV was performed on 67 eyes (33 sub-Tenon anesthesia, 34 general anesthesia). Pain during surgery in sub-Tenon anesthesia was 1.8 ± 2.2 (0.0-8.0), anxiety was 2.3 ± 2.2 (0.0-8.5). There was a moderate correlation between pain and anxiety (R2 = 0.58). Comparing sub-Tenon and general anesthesia no difference in pain perception was found the day after surgery. 27.3% of patients saw details, 21.2% saw colors, 90.1% saw light/motion perception, 3.0% had no light perception. Median chemosis after surgery was 1.0 (IQR = 1.0). Median motility of the eye during surgery was 1.0 (IQR = 1.0), median grade was 1.0 (IQR = 1.0). 24.2% of patients showed subconjunctival hemorrhage during or after surgery.

CONCLUSIONS

Sutureless pars-plana vitrectomy in sub-Tenon anesthesia was performed safely, with pain and anxiety levels tolerable for the patients and without the necessity for presence of an anesthesiologist. With 88.9% of patients willing to undergo vitreoretinal surgery in sub-Tenon anesthesia again, we recommend it as a standard option. Trial registration This study was approved by the Institutional Ethical Review Board of the RWTH Aachen University (EK 111/19). This study is listed on clinicaltrials.gov (ClinicalTrials.gov identifier: NCT04257188, February 5th 2020).

Evolution of operating microscopes and development of 3D visualization systems for intraocular surgery

The recent development of high-resolution, heads-up, 3D visualization microscopy systems has provided new technical and visualization options for ophthalmic surgeons. In this review, we explore the evolution of microscope technologies, the science behind modern 3D visualization microscopy systems, and the practical benefits (as well as disadvantages) that these systems provide over conventional microscopes for intraocular surgical practice. Overall, modern 3D visualization systems reduce the requirements for artificial illumination and provide enhanced visualization and resolution of ocular structures, improving ergonomics, and facilitating a superior educational experience. Even when considering their disadvantages, such as those related to technical feasibility, 3D visualization systems have an overall positive benefit/risk ratio. It is hoped these systems will be adopted into routine clinical practice, pending further clinical evidence on the benefits they may provide on clinical outcomes.

Feature Tracking and Segmentation in Real Time via Deep Learning in Vitreoretinal Surgery: A Platform for Artificial Intelligence-Mediated Surgical Guidance

PURPOSE

This study investigated whether a deep-learning neural network can detect and segment surgical instrumentation and relevant tissue boundaries and landmarks within the retina using imaging acquired from a surgical microscope in real time, with the goal of providing image-guided vitreoretinal (VR) microsurgery.

DESIGN

Retrospective analysis via a prospective, single-center study.

PARTICIPANTS

One hundred and one patients undergoing VR surgery, inclusive of core vitrectomy, membrane peeling, and endolaser application, in a university-based ophthalmology department between July 1, 2020, and September 1, 2021.

METHODS

A dataset composed of 606 surgical image frames was annotated by 3 VR surgeons. Annotation consisted of identifying the location and area of the following features, when present in-frame: vitrector-, forceps-, and endolaser tooltips, optic disc, fovea, retinal tears, retinal detachment, fibrovascular proliferation, endolaser spots, area where endolaser was applied, and macular hole. An instance segmentation fully convolutional neural network (YOLACT++) was adapted and trained, and fivefold cross-validation was employed to generate metrics for accuracy.

MAIN OUTCOME MEASURES

Area under the precision-recall curve (AUPR) for the detection of elements tracked and segmented in the final test dataset; the frames per second (FPS) for the assessment of suitability for real-time performance of the model.

RESULTS

The platform detected and classified the vitrector tooltip with a mean AUPR of 0.972 ± 0.009. The segmentation of target tissues, such as the optic disc, fovea, and macular hole reached mean AUPR values of 0.928 ± 0.013, 0.844 ± 0.039, and 0.916 ± 0.021, respectively. The postprocessed image was rendered at a full high-definition resolution of 1920 × 1080 pixels at 38.77 ± 1.52 FPS when attached to a surgical visualization system, reaching up to 87.44 ± 3.8 FPS.

CONCLUSIONS

Neural Networks can localize, classify, and segment tissues and instruments during VR procedures in real time. We propose a framework for developing surgical guidance and assessment platform that may guide surgical decision-making and help in formulating tools for systematic analyses of VR surgery. Potential applications include collision avoidance to prevent unintended instrument-tissue interactions and the extraction of spatial localization and movement of surgical instruments for surgical data science research.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Efficacy and safety of trans-sub-Tenon's retrobulbar anesthesia for pars plana vitrectomy: a randomized trial

AIM

To compare the efficacy and safety of trans-sub-Tenon's ciliary nerve block anesthesia and transcutaneous retrobulbar anesthesia in patients undergoing pars plana vitrectomy (PPV).

METHODS

A prospective, randomized, double-blinded clinical trial was conducted at Zhongda Hospital, Affiliated with Southeast University, from February 2021 to October 2021. Patients undergoing PPV were randomly allocated into two groups: the trans-sub-Tenon's anesthesia group (ST group) and the retrobulbar anesthesia group (RB group) in the ratio of 1:1. The ST group received 2 ml ropivacaine through the Tenon capsule to the retrobulbar space, while the RB group received 2 ml ropivacaine via transcutaneous retrobulbar injection. Visual analog score (VAS) was used to evaluate pain during the whole process, including during anesthesia implementation, intraoperatively and on the first day after the operation. Movement evaluation (Brahma scores) and anesthesia-related complications were also noted.

RESULTS

Finally, a total of 120 patients were included in the study (60 in the ST group and 60 in the RB group). There were no significant differences in baseline patient characteristics or surgical features between the two groups. The VAS pain scores for anesthesia implementation were 0.52 ± 0.47 in the ST group and 1.83 ± 0.87 in the RB group (P < 0.001). The VAS scores during the operation were 0.53 ± 0.49 in the ST group and 1.48 ± 1.02 in the RB group (P < 0.001) and those on the first day after the operation were 0.37 ± 0.38 in the ST group and 0.81 ± 0.80 in the RB group (P = 0.002). No patients required supplemental intravenous anesthesia intraoperatively. The Brahma movement scores were 0.70 ± 1.64 in the ST group (scores ranging from 0 to 8) and 2.38 ± 3.15 in the RB group (ranging from 0 to 12) (P = 0.001). Forty-two patients in each group received laser photocoagulation during surgery. Fifteen patients (36%) in the ST group could not see the flashes of the laser, compared to 8 patients (19%) in the RB group (P = 0.087). No serious sight-threatening or life-threatening complications related to anesthesia were observed in either group.

CONCLUSIONS

For PPV, trans-sub-Tenon's ciliary nerve block anesthesia was more effective in controlling pain than transcutaneous retrobulbar anesthesia during the whole surgery process, including during anesthesia implementation, intraoperatively and on the first day after the operation. Additionally, it could achieve better effect of akinesia and was relatively safe. Trans-sub-Tenon's anesthesia could be considered an alternative form of local anesthesia during vitreoretinal procedures.

TRIAL REGISTRATION

The study protocol has been registered at ChiCTR.org.cn on February 2021 under the number ChiCTR2100043109 .

Bupivacaine-lidocaine versus Ropivacaine-lidocaine Retrobulbar Anesthesia in Vitreoretinal Surgery

Purpose: To compare efficacies of bupivacaine-lidocaine and ropivacaine-lidocaine mixtures in terms of inducing retrobulbar anesthesia during vitrectomy.Methods: Sixty patients who underwent retrobulbar anesthesia during vitrectomy were divided into two groups. Patients in group 1 received a mixture of bupivacaine and lidocaine (n = 30); patients in group 2 received a mixture of ropivacaine and lidocaine (n = 30). The effects of the two combinations were retrospectively compared and analyzed. The onset times of analgesia and akinesia were measured. Two hours after surgery, sensory blockade was assessed by touching the corneas with cotton swabs and by communicating with patients. Ocular movement was evaluated in four gaze direction quadrants. A 10-point visual analog pain scale was used to assess pain during and 2 hours after surgery. Intra- and postoperative complications were recorded.Results: The mean analgesia onset times in groups 1 and 2 were 94.62 ± 28.87 and 92.32 ± 35.53 seconds, respectively (p = 0.071); the mean akinesia onset times were 147.89 ± 59.35 and 132.57 ± 76.38 seconds (p = 0.223), respectively. Patients in group 2 reported significantly less postoperative pain and exhibited less postoperative ocular movement, compared with patients in group 1 (both p = 0.002). One patient in group 1 experienced respiratory depression after retrobulbar blockade.Conclusions: When retrobulbar anesthesia is required during vitrectomy, a ropivacaine-lidocaine mixture and a bupivacaine-lidocaine mixture induce anesthesia with similar rapidity. However, the ropivacaine-lidocaine mixture is safer and affords better-quality intra- and postoperative anesthesia.

Pain during pars plana vitrectomy following sub-Tenon versus peribulbar anesthesia: A randomized trial

Purpose

To compare pain during pars plana vitrectomy (PPV) following topical lidocaine jelly and sub-Tenon anesthesia versus peribulbar anesthesia.

Methods

Prospective, single-center, randomized study. Patients scheduled for PPV for macular hole (MH) or epiretinal membrane (ERM) at the Retina and Vitreous Section of the Department of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo were randomly assigned to one of two groups in a 1:1 allocation ratio. Patients assigned to Group ST received topical anesthesia with 2% lidocaine jelly followed by sub-Tenon anesthesia with 2–4 ml of 1% ropivacaine. Patients assigned to PB received peribulbar anesthesia with 4–6 ml of 1% ropivacaine. After PPV, patients in both groups were asked to rate the level of pain they felt during the entire procedure (including anesthesia administration and PPV) by pointing at a 0–100 Visual Analogue Pain Scale (VAS). Data regarding demographics, patient characteristics and surgical features were also collected.

Results

Fifty-four patients were enrolled in the study (26 in Group ST and 28 in Group PB). Baseline characteristics, including age, gender, and presence of comorbidities, were similar in both groups. The surgery performed was PPV alone in 10 and 14 patients in the ST and PB groups, respectively, and combined phacoemulsification and PPV in 16 and 14 patients in the ST and PB groups, respectively (p = 0.39, Pearson). Surgery duration (mean ± SD minutes) was similar in the two groups (62 ± 12 for ST and 70 ± 20 for PB, p = 0.09, t-Test). No patients needed supplemental topical or intravenous anesthesia during surgery. No sight- or life-threatening complication was observed in either group. VAS score was significantly lower in the ST compared to the PB group (median (interquartile range) was 1 (2.25–0) in the ST group compared to 11.5 (29.75–5) in the PB group, p< 0.0001, Wilcoxon).

Conclusion

In this study of patients who underwent PPV for MH or ERM, topical followed by sub-Tenon anesthesia was more effective in controlling pain during the whole vitrectomy procedure than peribulbar anesthesia. Compared to peribulbar anesthesia which is administered with a sharp needle, sub-Tenon anesthesia administered with a blunt cannula may be associated with a reduced risk of such adverse events as globe perforation, retrobulbar hemorrhage, and inadvertent injection of anesthesia into the optic nerve sheath.

Testing the Biocompatibility of a Glutathione-containing Intraocular Irrigation Solution by Using an Isolated Perfused Bovine Retina Organ Culture Model — an Alternative to Animal Testing

The effects of a glutathione-containing intraocular irrigation solution, BSS Plus®, on retinal function and on the survival of ganglion cells in whole-mount retinal explants were studied. Evidence is provided that the perfused ex vivo bovine retina can serve as an alternative to in vivo animal testing. Isolated bovine retinas were prepared and perfused with an oxygen-saturated standard irrigation solution, and an electroretinogram was recorded to assess retinal function. After stable b-waves were detected, the isolated retinas were perfused with BSS Plus for 45 minutes. To investigate the effects of BSS Plus on photoreceptor function, 1mM aspartate was added to the irrigation solution in order to obtain a-waves, and the ERG trace was monitored for 75 minutes. For histological analysis, isolated whole retinal mounts were stored for 24 hours at 4°C, in the dark. The percentages of cell death in the retinal ganglion cell layer and in the outer and inner nuclear layers were estimated by using an ethidium homodimer-1 stain and the TUNEL assay. General swelling of the retina was examined with high-resolution optical coherence tomography. During perfusion with BSS Plus, no significant changes in a-wave and b-wave amplitudes were recorded. Retinas stored for 24 hours in BSS Plus showed a statistically significant smaller percentage (52.6%, standard deviation [SD] = 16.1%) of cell death in the retinal ganglion cell layer compared to the control group (69.6%, SD = 3.9, p = 0.0031). BSS Plus did not seem to affect short-term retinal function, and had a beneficial effect on the survival of retinal ganglion cells. This method for analysing the isolated perfused retina represents a valuable alternative for testing substances for their retinal biocompatibility and toxicity.