SMALL-GAUGE VALVED VERSUS NONVALVED CANNULA PARS PLANA VITRECTOMY FOR RETINAL DETACHMENT REPAIR

Small-Gauge Vitrectomy for Macular Surgery Using a Systematic Approach to Wound Closure: 27-Gauge vs 25-Gauge

Purpose: To evaluate the effectiveness of and to compare vitrectomy performed with 25-gauge or 27-gauge instrumentation for macular surgery by assessing the surgical duration, wound closure, and complication rate using a systematic approach to wound closure. Methods: In this retrospective chart review, 125 25-gauge and 125 27-gauge consecutive small-gauge vitrectomy surgeries for epiretinal membrane, macular hole, vitreomacular adhesion, or a combination were analyzed during and immediately after surgery. Wound closure was performed using a systematic protocol. Results: Baseline characteristics were not statistically different between the 2 groups. The surgical duration was similar with 25-gauge vitrectomy and 27-gauge vitrectomy (P = .07). Although spontaneous wound closure was common in both groups, it was more common in the 27-gauge group (P = .22). Intraoperative and postoperative complications were uncommon in both groups. Conclusions: Findings show that 27-gauge vitrectomy is a safe, effective alternative to the more commonly used 25-gauge vitrectomy for macular surgery. Less manipulation was required to achieve wound closure with 27-gauge vitrectomy using a standardized wound-closure protocol. Smaller 27-gauge vitrectomy did not increase surgical time or complications over 25-gauge vitrectomy for macular surgery.

Conjunctival Pigmentation Following Pars Plana Vitrectomy (PPV) for Rhegmatogenous Retinal Detachment: Risk Factors and Outcomes

Purpose: To investigate the incidence and the risk factors for conjunctival pigmentation at the sclerotomy sites following valved and non-valved cannula pars plana vitrectomy (PPV) performed by different surgical techniques.

Methods: This is a prospective observational study which included 70 eyes of 70 patients who underwent PPV for rhegmatogenous retinal detachment with follow-up visits at 1, 3, 6, 12, and 24 months. Twenty-eight eyes were operated using 25G non-valved cannulas (Group A), 22 eyes using 25G non-valved cannulas (Group B), and 20 eyes using 25G valved cannulas (Group C). The evaluated clinical parameters include the surgical technique, the patients' age, the number of retinal tears, the tamponade agent, the presence of residual sub-retinal fluid (SRF), and the duration of postoperative posturing.

Results: Group A was associated with significant conjunctival pigmentation at up to 6 months after PPV. Sulfur hexafluoride (SF6) gas tamponade was associated with less conjunctival pigmentation at 3 months follow-up visit [odds ratio, OR 0.09 (95% confidence interval, CI 0.01; 0.67)], whereas the presence of residual SRF was a significant risk factor for postoperative pigmentation at 1-year follow-up visit [OR 5.89 (95% CI 1.84; 23.12)]. The area of measured pigmentation was also positively correlated to the number of retinal tears at all follow-up visits over 2 years. Six patients presented with conjunctival pigmentation at 2 years follow-up visit.

Conclusion: New vitrectomy techniques with valved cannulas prevent the postoperative appearance of conjunctival pigmentation. The number of retinal tears, the presence of SRF, and the use of long-standing tamponade agents were the most significant predisposing factors. The post-vitrectomy conjunctival pigmentation gradually reduces over time.

Pars plana vitrectomy in uveitis in the era of microincision vitreous surgery

Pars plana vitrectomy (PPV) in uveitis is indicated for various diagnostic and therapeutic indications. With the advent of microincision vitreous surgery (MIVS), the use of PPV in uveitis has increased with a wider spectrum of indications due to shorter surgical time, less patient discomfort, less conjunctival scarring, and a decreased rate of complications as compared to standard 20G vitrectomy. Because of faster post-operative recovery in terms of visual improvement and reduction of inflammation, and reduced duration of systemic corticosteroids, MIVS has gained popularity in uveitis as an adjunctive therapy to the standard of care medical therapy. The safety and efficacy of MIVS is related to the emerging vitrectomy techniques with better and newer cutters, illuminating probes, and accessory instruments. Because of the instrumentation and fluidics of MIVS, PPV is emerging as a safe and useful alternative for diagnostic challenges in uveitis, aiding in earlier diagnosis and better outcome of inflammatory disease, even in the presence of severe and active inflammation, which was once considered a relative contraindication for performing vitreous surgery. However, for surgical interventions for therapeutic indications and complications of uveitis, it is advisable to achieve an optimum control of inflammation for best results. The increasing reports of the use of MIVS in uveitis have led to its wider acceptance among clinicians practicing uveitis.

Hybrid 23/27 Gauge Vitrectomy - Combining the Charm of 27G with the Efficacy of 23G

Background

Minimally invasive transconjunctival sutureless vitrectomy (MIVS) has evolved into the standard of care, smaller incisions thought to result in lower ocular surface trauma and shorter times to recovery. The currently most relevant limitations in macular surgery may be light intensity and 27G instrument stability. Therefore, we thought to compare standard 23 and 27G vitrectomy with a hybrid technique using one 23G and two 27G ports regarding surgical times and short-term outcomes.

Methods

This retrospective comparison included 90 single-center consecutive cases of eyes undergoing elective micro-invasive vitrectomy for epiretinal membranes or idiopathic macular holes between October 2017 and June 2018. The main criteria for the comparison were total surgical time as primary outcome parameter and treatment-demanding intra- and postoperative complications along with recovery of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from prior to surgery to 1 month thereafter as secondary parameters as independent parameters for the recovery from the pre-existing pathology and the surgical trauma.

Results

Surgical times were shorter with 23G and 23/27G compared to 27G (23G: 38.4±13.1; 27G: 48.1±15.3; 23/27G: 34.9±9 mins; p=0.0005) with no differences in BCVA and CRT outcomes. Switching from 27G to a larger port size was not necessary in any instance. Cryotherapy was applied in 15%, 30%, and 22.5% to suspected retinal pathologies, beyond these, in 5%, 0%, and 7.5% for retinal tears. Four postoperative retinal detachments occurred (4.4%), one in the 23G and three in the 23/27G group requiring re-vitrectomy.

Conclusion

In this exploratory case series, 23/27G hybrid vitrectomy, combining the advantages of 23G and 27G techniques, resulted in shorter surgical times without evident disadvantages. The combination with cataract surgery was unproblematic.

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.

VITREOUS INCARCERATION IN SCLEROTOMIES AFTER VALVED 23-, 25-, OR 27-GAUGE AND NONVALVED 23- OR 25-GAUGE MACULAR SURGERY

PURPOSE

To study the patterns of vitreous incarceration at sclerotomy sites by ultrasound biomicroscopy in patients subjected to valved or nonvalved small-gauge pars plana vitrectomy.

METHODS

A prospective comparative study of 88 eyes affected by epiretinal membrane and macular hole. Patients were divided into four groups: valved or nonvalved 23-gauge (16 eyes each) and valved or nonvalved 25-gauge (20 eyes each); their vitreal disposition was compared by ultrasound biomicroscopy. Vitreal disposition was also assessed in 16 eyes of 16 patients subjected to valved 27-gauge pars plana vitrectomy.

RESULTS

Three vitreal patterns were identified: P0 (vitreous not visible or vitreous strand distant from the sclerotomy site), P1 (vitreous strand parallel to and in contact with the sclerotomy site), and P2 (vitreous strand entrapped in the sclerotomy site). The effect of valved trocar use on vitreous incarceration seemed to be somewhat beneficial, but no statistically significant effect could be shown (odds ratio: 0.85, 95% confidence interval: 0.42-1.74, P = 0.657). Similarly, no differences in vitreous incarceration were shown among vitrectomy gauges (23, 25, or 27) both in a model including valved trocars only (P = 0.858) and in a model with all available data (P = 0.935).

CONCLUSION

In 23- and 25-gauge macular surgeries, postoperative vitreous incarceration does not seem to be reduced using valved cannulas and was similar to that observed in 27-gauge surgery.

Review of Small Gauge Vitrectomy: Progress and Innovations

Purpose. To summarise the surgical advances and evolution of small gauge vitrectomy and discuss its principles and application in modern vitreoretinal surgery. The advent of microincisional vitrectomy systems (MIVS) has created a paradigm shift away from twenty-gauge vitrectomy systems, which have been the gold standard in the surgical management of vitreoretinal diseases for over thirty years. Advances in biomedical engineering and surgical techniques have overcome the technical hurdles of shifting to smaller gauge instrumentation and sutureless surgery, improving surgical capabilities and expanding the indications for MIVS.

Valved versus nonvalved cannula small-gauge pars plana vitrectomy for repair of retinal detachments with Grade C proliferative vitreoretinopathy

Purpose

Valved cannulas are a recent addition to small-gauge pars plana vitrectomy (PPV) and provide stable intraocular fluidics. The goal of this study was to compare outcomes and postoperative complication rates of valved vs nonvalved cannula small-gauge PPV for repair of retinal detachments (RDs) complicated by Grade C proliferative vitreoretinopathy (PVR).

Methods

A retrospective chart review of 364 consecutive eyes with either valved or nonvalved cannula PPV for RD repair was performed. The primary outcomes were single surgery and final anatomic success and change in best-corrected visual acuity for repair of RDs complicated by Grade C PVR.

Results

We identified 36 eyes in the valved group and 31 eyes in the nonvalved group with Grade C PVR RD. The single surgery success was 83% vs 77% (P=0.555) and the final anatomic success was 94% vs 87% (P=0.404) in the valved vs nonvalved eyes, respectively. The mean final visual acuity gain was −0.36 logarithm of the minimum angle of resolution (logMAR; approximate Early Treatment Diabetes Retinopathy Study [ETDRS] score =17 letters) in valved eyes vs −0.33 logMAR (approximate ETDRS score =16 letters) in nonvalved eyes (P=0.81). Postoperative complication rates including postoperative day 1 hypotony, hypertony, and anterior chamber fibrin formation; postoperative retention of intraocular or subretinal perfluorocarbon liquid; and subsequent epiretinal membrane peel were not statistically different between groups.

Conclusion

Valved cannula PPV yields equivalent visual acuity and anatomic outcomes without increased postoperative complication rates compared to traditional nonvalved cannula PPV for Grade C PVR-associated RD repair.