The competency of pars plana vitrectomy incisions: a comparative histologic and spectrophotometric analysis

Clinical Factors and Outcomes of Acute-Onset Endophthalmitis Following Small-Gauge Pars Plana Vitrectomy Surgery

BACKGROUND AND OBJECTIVES

Describe risk factors, findings, and outcomes of acute endophthalmitis (AE) following small-gauge pars plana vitrectomy (PPV).

PATIENTS AND METHODS

This was a retrospective single-center, nonrandomized study of post-PPV AE patients from 2013 to 2021. All received vitreous biopsy before treatment. Patients were divided into cohorts: 1) PPV within 3 days of diagnosis (Urgent-PPV), and 2) no urgent PPV (Other-treatment [Tx]). Main outcome was best-corrected visual acuity (BCVA) at 6 months.

RESULTS

Twenty-one patients were analyzed. Epiretinal membrane was most common indication for PPV (48%). Incidence was 0.074%. Culture-positive rate was 57%. For final BCVA, there was no significant (P = 0.85) difference between Urgent-PPV (median = 0.40 logMAR) and Other Tx cohorts (median = 0.35 logMAR). Sclerotomy wounds were not sutured in 71% of patients. Approximately 24% and 38% of patients analyzed had either no tamponade or partial tamponade, respectively.

CONCLUSION

Tamponade agents and sclerotomy suturing may be important factors when evaluating post-small-gauge PPV-associated AE. Further studies are necessary for clarification. [Ophthalmic Surg Lasers Imaging Retina 2023;54:xx-xx.].

Intraoperative choroidal detachment during small-gauge vitrectomy: analysis of causes, anatomic, and visual outcomes

INTRODUCTION

To investigate the incidence and causes of intraoperative choroidal detachment (CD) during small-gauge vitrectomy, as well as the anatomic and visual outcomes.

METHODS

We retrospectively reviewed the medical records of 1026 consecutive patients who underwent small-gauge vitrectomy from June 2017 to December 2018 at Zhongshan Ophthalmic Centre, Guangzhou, China. Data on the presence, location, and extent of intraoperative CD and its relationship to the infusion cannula were collected. Patient demographic characteristics and postoperative anatomic and visual outcomes were also assessed.

RESULTS

A total of six cases were found to have intraoperative CD, including two with serous CD, three with limited haemorrhagic CD, and one with CD caused by inadvertent perfusion of gas during air/fluid exchange. Retraction of the infusion cannula and acute ocular hypotony were found to be the main causes of intraoperative CD in five out of the six cases. The best-corrected visual acuity of all cases significantly improved after the surgery.

CONCLUSION

The incidence of intraoperative CD during small-gauge vitrectomy is low; the predominant causes are retraction of the infusion cannula and acute ocular hypotony. Immediate awareness and timely closure of the incision may contribute to a better surgical prognosis.

SUTURELESS CLOSURE OF 23- AND 25-GAUGE LEAKING SCLEROTOMIES WITH THE SCLERAL NEEDLING TECHNIQUE

PURPOSE

To describe and evaluate the efficacy of a novel technique, scleral needling (SN), for securing 23- and 25-gauge leaking sclerotomies in microincision vitrectomy surgery.

METHODS

A retrospective comparative review of consecutive cases of 23- and 25-gauge pars plana vitrectomy performed by a single vitreoretinal surgeon before the introduction of the SN technique (pre-SN; November 2016 to January 2017) and after the introduction of the SN technique (post-SN; November 2017 to January 2018) was conducted. The SN technique was implemented as an alternative to suturing, using a 30-gauge needle inserted perpendicularly through the full thickness of the sclera adjacent to the scleral opening, with the needle then immediately removed and sclerotomy closure confirmed.

RESULTS

A total of 203 eyes, 105 from pre-SN and 98 from post-SN, were included in the study. The number of eyes requiring suture closure was significantly reduced from 39% in the pre-SN group to 2% in the post-SN group (P < 0.001). The mean postoperative intraocular pressure and incidence of hypotony on Days 1 to 2, Days 3 to 20, and Days 21 to 50 was not significantly different between the pre-SN and post-SN groups. No major complications associated with the SN technique were noted during the study period.

CONCLUSION

The SN technique is a safe and simple method for effectively securing leaking sclerotomies in microincision vitrectomy surgery.

Treatment-Emergent Adverse Events in Gene Therapy Trials for Inherited Retinal Diseases: A Narrative Review

Patient safety is a primary priority in the conduction of retinal gene therapy trials. An understanding of risk factors and mitigation strategies for post-procedure complications is crucial for the optimization of gene therapy clinical trial protocols. In this review, we synthesize the literature on ocular delivery methods, vector platforms, and treatment-emergent adverse effects in recent gene therapy clinical trials for inherited retinal diseases.

Vitreous incarceration in sutured vs non-sutured sclerotomies after 25-gauge macular surgery

OBJECTIVES

To study the patterns of vitreous incarceration in sutured vs non-sutured sclerotomies in patients subjected to 25-gauge macular surgery.

METHODS

A prospective study of 135 eyes affected by epiretinal membrane or macular hole. Vitreal disposition was evaluated via ultrasound biomicroscopy (UBM) at the sclerotomy sites between 30 and 40 days after surgery, once the tamponade had completely disappeared.

RESULTS

In total, 349 sclerotomies (86.2%) of 99 patients were non-sutured while 56 sclerotomies (13.8%) of 36 patients were sutured at the end of the surgical procedure. Among the 36 patients with sutured sclerotomies, 15 out of 36 (41.6%) had at least two sclerotomies sutured. All the sclerotomy sites were evaluated (405 sclerotomies). Sclerotomy suture was significantly associated with a less aggressive pattern of vitreal incarceration (OR: 0.16, 95% CI: 0.07-0.35, p < 0.001). Compared to preoperative values, day 1 post operative IOP was not significantly different in patients with sutured sclerotomies, while patients with non-sutured sclerotomies had a significantly lower day 1 post operative IOP.

CONCLUSIONS

In 25-gauge macular surgery, UBM evaluation documented a higher rate of postoperative vitreous incarceration in the non-sutured sclerotomies, confirming the previously postulated role of the residual vitreous, left at the end of the surgery, in closing the sclerotomy site.

Association of Acute Endophthalmitis With Intravitreal Injections of Corticosteroids or Anti-Vascular Growth Factor Agents in a Nationwide Study in France

Importance

The number of patients affected by retinal diseases treated with intravitreal injections (IVTs) has resulted in a rapidly growing number of procedures. One of the worst complications after these injections is endophthalmitis.

Objective

To evaluate the incidence of acute endophthalmitis after IVTs of corticosteroids or anti-vascular endothelial growth factor (anti-VEGF) agents.

Design, Setting, and Participants

This population-based cohort study included patients undergoing IVTs from January 1, 2012, through December 31, 2015, in France. Data were acquired from the French medical-administrative database (Système National d'Information Inter-Régime de l'Assurance Maladie), which collects hospitalization discharge abstracts and out-of-hospital care information for the whole country. Data were analyzed from March through July 2017.

Exposures

Intravitreal injections of corticosteroid or anti-VEGF agents.

Main Outcomes and Measures

Incidence of acute endophthalmitis within 6 weeks after IVT by means of billing codes from a national database.

Results

During the study period, 1 811 977 IVTs of corticosteroids or anti-VEGF agents performed on 254 927 patients (60.4% female; median age, 79 years [interquartile range, 70-85 years]) were analyzed. A total of 444 acute endophthalmitis cases (crude incidence, 0.0245%) were recorded. In multivariable analysis, which did not include adjustment for when the endophthalmitis occurred during the study period, the risk of endophthalmitis was lower in male patients (incidence rate ratio [IRR], 0.78; 95% CI, 0.63-0.96; P = .02), higher for corticosteroids than for anti-VEGF agents (IRR, 3.21; 95% CI, 2.33-4.44; P < .001), and higher for nonprefilled syringes of anti-VEGF medications than prefilled syringes for ranibizumab (IRR, 1.63; 95% CI, 1.15-2.30) and aflibercept (IRR, 1.82; 95% CI, 1.25-2.66; P < .001).

Conclusions and Relevance

The findings from this study of a nationwide database appear to have confirmed the low incidence rate of acute endophthalmitis after IVTs of corticosteroids or anti-VEGF agents. Although an association may not necessarily indicate a cause and effect, the risk for acute endophthalmitis after IVTs appeared to be higher for corticosteroids compared with anti-VEGF agents, while a lower risk of endophthalmitis appeared to be found with prefilled syringes of anti-VEGF medications.

SCLEROTOMY LEAKAGE IN TRANSCONJUNCTIVAL SMALL-GAUGE PARS PLANA VITRECTOMY: Effect of Removing the Cannula Over the Light Pipe

PURPOSE

To determine the effect of cannula removal over the light pipe on the incidence of sclerotomy leakage and to evaluate other factors that may influence the incidence of sclerotomy leaks and hypotony on conclusion of small-gauge transconjunctival pars plana vitrectomy.

METHODS

Retrospective, interventional clinical study of consecutive patients who underwent small-gauge transconjunctival pars plana vitrectomy at a single academic center. Eyes were divided into a group in which cannulae were removed over the light pipe (Group L) and a group in which cannulae were simply pulled out (Group N). The primary comparison was the comparison in requirement for suturing of sclerotomies between Groups L and N.

RESULTS

Forty-eight eyes of 48 patients were included in the study (Group L: 21 eyes; Group N: 27 eyes). In Group L, 14/42 (33%) superior sclerotomies required suturing compared with 7/54 (13%) sclerotomies in Group N (P = 0.024). Superior sclerotomy leaks were also more common in Group L (28/42, 67%) compared with Group N (23/54, 43%, P = 0.024). Similarly, more eyes had hypotony after cannula removal in Group L (11/21; 52%) compared with Group N (5/27; 19%, P = 0.03). There were no differences in any of these measures when comparing fluid-filled to air- or gas-filled eyes.

CONCLUSION

Removing the cannula over the light pipe results in a greater frequency of leaking, including leaking that results in hypotony or that requires suturing. The technique of cannula removal affects the risk of leakage and the risk of requiring suturing of a sclerotomy.

Postoperative Endophthalmitis: A Review of Risk Factors, Prophylaxis, Incidence, Microbiology, Treatment, and Outcomes

Postoperative endophthalmitis is one of the most feared complications of intraocular surgery. The most common types of intraocular surgeries performed worldwide are cataract extraction, glaucoma drainage implants/trabeculectomy, and pars plana vitrectomy. This review will focus on the clinical features, risk factors, prophylaxis, and treatment of endophthalmitis in these three main intraocular surgeries.

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.

Endophthalmitis after small-gauge vitrectomy: a retrospective case series from Sweden

PURPOSE

To investigate the anatomical and functional outcomes of acute-onset endophthalmitis after small-gauge vitrectomy.

METHODS

Retrospective case series of patients who underwent 23- or 25-gauge vitrectomy at four centres in Sweden between 2008 and 2012. Postvitrectomy endophthalmitis was identified through the search of the journal records of each institution, and the diagnosis was based on clinical criteria regardless of culture results.

RESULTS

Twenty-four patients (24 eyes) were included. The incidence of endophthalmitis following small-gauge vitrectomy was 0.14%. Indications for small-gauge vitrectomy enclosed epiretinal membrane (n = 13), retinal detachment (n = 5) and others (n = 6). Surgical technique included 23- and 25-gauge vitrectomy (23:1). Four eyes had sutured sclerotomies, and two had postoperative hypotony <7 mmHg. Days to endophthalmitis presentation varied between 1 and 21 (mean 6 ± 6). Treatment methods included the following: tap and antibiotic injection (n = 7), tap, antibiotic injection with subsequent vitrectomy (n = 2) and prompt vitrectomy with antibiotics (n = 15). Sixteen eyes (66.7%) were culture positive, whereas the other eight cases were culture negative. Anatomical results included evisceration (n = 1), phthisis (n = 1), and globe intact (n = 22). Presenting best corrected visual acuity (BCVA) were hand motion (n = 14), light perception (n = 7), counting fingers (n = 2), and no data (n = 1). Functionally 19 eyes (79%) had Snellen VA ≥0.1; 11 eyes (46%) had VA ≥0.5 Mean logMar BCVA preoperatively and at the last follow-up were 2.07 ± 0.6 and 0.79 ± 0.99, respectively.

CONCLUSIONS

In spite of good anatomical and functional results, this study showed higher rate of endophthalmitis than the latest reports suggesting that small-gauge vitrectomy has reached the safety level of standard 20-gauge vitrectomy when infectious endophthalmitis is concerned.

Outcomes of 27 Gauge Microincision Vitrectomy Surgery for Posterior Segment Disease

PURPOSE

To report the initial experience, clinical outcomes, and safety profile of 27 gauge pars plana vitrectomy (PPV) in eyes with posterior segment disease.

DESIGN

Multicenter, retrospective, interventional case series.

METHODS

setting: Private practice and tertiary care settings.

STUDY POPULATION

Eyes undergoing 27 gauge PPV for a vitreoretinal surgery indication.

INTERVENTION

Three-port, transconjunctival 27 gauge PPV.

MAIN OUTCOME MEASURES

Change in visual acuity and occurrence of intraoperative and postoperative complications with minimum follow-up of 90 days.

RESULTS

Ninety-five eyes met the inclusion criteria. Surgical indications included epiretinal membrane (n = 26), diabetic tractional retinal detachment (n = 14), full-thickness macular hole (n = 11), rhegmatogenous retinal detachment with (n = 7) or without (n = 9) proliferative vitreoretinopathy (PVR), vitreous hemorrhage (n = 10), vitreous opacities (n = 8), endophthalmitis (n = 4), sub-silicone oil retinal detachment (n = 3), retained lens material (n = 1), submacular hemorrhage (n = 1), and aqueous misdirection (n = 1). Mean logMAR visual acuity improved from 1.08 ± 0.71 (20/240 Snellen equivalent) preoperatively to 0.53 ± 0.65 (20/67 Snellen equivalent) postoperatively (P < .001). Mean follow-up was 144 days (median 127 days, range 90-254 days). There were no intraoperative complications and no case required conversion to 20, 23, or 25 gauge instrumentation. A total of 3 sclerotomy sites (1.1%) were sutured at the conclusion of surgery. Postoperative complications included transient ocular hypertension in 8 eyes (8.4%), transient hypotony in 5 eyes (5.3%), and vitreous hemorrhage in 5 eyes (5.3%). No cases of postoperative endophthalmitis, sclerotomy-related retinal tears, or choroidal detachments were encountered in the follow-up period.

CONCLUSION

The 27 gauge PPV was well tolerated with low rates of intraoperative and postoperative complications across varied surgical indications.

Comparison of the effects of 23-gauge and 25-gauge microincision vitrectomy blade designs on incision architecture

Purpose

To compare the effects of different 23- and 25-gauge microincision vitrectomy trocar cannula entry systems on incision architecture.

Methods

We tested one ridged microvitreoretinal (MVR), one non-ridged MVR, one pointed beveled, and one round-tipped beveled blade (n=10 per blade design per incision type). Each blade’s straight and oblique incision architecture was assessed in a silicone disc simulating the sclera. Wound leakage under pressure and endoscopic observations were conducted on sclerotomy sites of isolated porcine eyes (n=4 per blade design) after simulated vitrectomy.

Results

Differences in blade design created distinct incision architecture. Incisions were linear with the ridged MVR blade, flattened “M-shaped” with the non-ridged MVR blade, asymmetrical chevron-shaped with the pointed beveled blade, and curved with the round-tipped beveled blade. With the exception of oblique entry incision thickness, both MVR blade designs created thinner incisions than the beveled blades at entry and exit sites. Only the ridged MVR blade created incisions with no leakage. Vitreous incarceration was observed with all trocar cannula systems.

Conclusion

Wound closure in porcine eyes was similar with all blades despite differences in incision architecture. Wound leakage occurred at low to moderate infusion pressures with most blades; no wound leakage was observed with ridged MVR blades.

Endophthalmitis following pars plana vitrectomy: a literature review of incidence, causative organisms, and treatment outcomes

Endophthalmitis following pars plana vitrectomy is a very uncommon cause of endophthalmitis. Cases reported over the last decade show a decrease in incidence over time. To optimize visual outcome, early diagnosis and treatment are essential. In this review we report a summary of the incidence of endophthalmitis following vitrectomy, various risk factors for their occurrence, the microbiological profile and the visual outcomes post treatment.

A prospective and nationwide study investigating endophthalmitis following pars plana vitrectomy: incidence and risk factors

BACKGROUND/AIMS

This is the first nationwide prospective study to investigate the incidence and risk factors of endophthalmitis following pars plana vitrectomy (PPV).

METHODS

This was a prospective, nationwide case-control study. Cases of presumed infectious endophthalmitis within 6 weeks of PPV were reported via the established British Ophthalmological Surveillance Unit. The surveillance period was 2 years. Controls (patients who had PPV but no endophthalmitis) were recruited from nine randomly selected UK centres.

RESULTS

37 reports were received and 28 cases met the diagnostic criteria for presumed infectious endophthalmitis following PPV. The incidence of endophthalmitis following PPV was 28 cases per 48 433 PPVs (1 in 1730 with a 95% CI of 1 in 1263 to 1 in 2747). 272 controls were randomly recruited from nine UK centres. Smaller gauge port sizes were not found to be a risk. Immunosuppression (OR 19.0, p=0.001) and preoperative topical steroids (OR 131.4, p<0.001) increased the endophthalmitis risk. Operating for retinal detachment was associated with a reduced risk of endophthalmitis (OR 0.10, p=0.005).

CONCLUSIONS

Endophthalmitis following PPV is rare. Operating with smaller gauge port sizes does not increase the risk of endophthalmitis.

Comparison of two scleral incision techniques in 23-gauge transconjunctival vitrectomy

BACKGROUND AND OBJECTIVE

To compare two 23-gauge transconjunctival vitrectomy incision techniques, parallel and perpendicular to the alignment of scleral fibers, in terms of hypotony and postoperative intraocular pressure (IOP).

PATIENTS AND METHODS

Fifty-three eyes of 53 patients who underwent 23-gauge one-step trocar pars plana vitrectomy were randomly assigned to undergo scleral incision parallel (group 1, 26 eyes) or perpendicular (group 2, 27 eyes) to the limbus. Patients were observed postoperatively for wound healing, leakage, endophthalmitis, IOP, and hypotony at 1 day, 1 week, and 1, 3, 6, and 9 months.

RESULTS

No difference in preoperative IOP was observed (P = .229). Postoperative IOP was significantly lower in group 2 (P = .009). Hypotony rates did not differ between the groups. Intraocular gas or silicone tamponade was used intraoperatively in 26 cases. In cases in which no gas or silicone was given (n = 27), IOP measurements were significantly lower in group 2 (P = .021). There was no difference in hypotony ratios for gas/silicone injection versus no injection (P = 1.00) or in postoperative visual acuity (P = .350). Visual acuity improved significantly in both groups at follow-up examinations.

CONCLUSION

Parallel and perpendicular incisions resulted in similar postoperative hypotony rates, but perpendicular incisions were associated with lower IOP.

Changes in day 1 post-operative intraocular pressure following sutureless 23-gauge and conventional 20-gauge pars plana vitrectomy

Background/Aims:

The benefits associated with transconjunctival sutureless vitrectomy techniques are continuing to be defined. The purpose of this study was to compare the incidence of extreme changes in day 1 intraocular pressure (IOP) following 23-gauge sutureless vitrectomy compared with conventional 20-gauge vitrectomy.

Methods:

Fifty consecutive 23-gauge and 50 consecutive 20-gauge cases were included; eyes with a history of previous vitreoretinal surgery were excluded. 23-gauge surgery was completed with passive fluid air exchange where no long acting tamponade was indicated. The surgery remained sutureless unless a leak was visible at the end of the procedure. Data were collected by retrospective case note review. Statistical analysis was carried out using Fisher’s exact and chi-square tests.

Results:

Twenty-two percent (11/50) of 23-gauge vitrectomies required suturing of one or more ports. On the first post-operative day hypotony (IOP<5mmHg) occurred in 1/50 eyes in the 20- and 23-gauge groups. Raised pressure (IOP>21mmHg) occurred in 30% (15/50) of eyes in the 20-gauge group and 8% (4/50) of eyes in the 23-gauge group; IOP>30mmHg only occurred in the 20-gauge group (3/50).

Conclusion:

Fluid air exchange following 23-gauge vitrectomy is associated with very low risk of day 1 hypotony. This predominantly sutureless technique appears to reduce the incidence and magnitude of early post-operative IOP elevation compared with conventional 20-gauge vitrectomy.

Reduction of vitreous contamination rate after 25-gauge vitrectomy by surface irrigation with 0.25% povidone-iodine

PURPOSE

To examine whether repeated ocular surface irrigation with 0.25% povidone-iodine, which is highly bactericidal and nonoculotoxic, reduces bacterial contamination of the vitreous during 25-gauge vitrectomy.

METHODS

Overall, 4,407 eyes undergoing 25-gauge vitrectomy were studied; of these, 2,801 were irrigated with infusion fluid (group A) and 1,606 with 0.25% povidone-iodine (group B). In each group (A and B), 103 eyes were studied bacteriologically, using ocular surface fluid samples after placing lid speculum (S1), after operative field irrigation (S2), and in vitreous samples at the beginning (V1) and at the completion of vitrectomy (V2).

RESULTS

Bacterial contamination rate in S1 did not differ significantly between the groups A (5.5%) and B (6.8%). However, the contamination rates in S2, V1, and V2 were apparently lower in group B (0%, 0%, and 0%, respectively) than in group A (2.0%, 1.0%, and 2.0%, respectively). Incidence of endophthalmitis was 0 of 2,801 eyes in group A and 0 of 1,606 eyes in group B.

CONCLUSION

In 25-gauge vitrectomy, repeated operative field irrigation with 0.25% povidone-iodine reduced bacterial contamination in vitreous to extremely low level.

Comparison of the 20-gauge conventional vitrectomy technique with the 23-gauge releasable suture vitrectomy technique

PURPOSE

To compare the efficacy of the transconjunctival releasable suture technique for pars plana vitrectomy using 23-gauge (23G) instruments versus the conventional 20-gauge (20G) technique.

METHODS

A retrospective and interventional case series was consecutively performed for 199 eyes of the 192 patients that were a part of this study. Clinical data were reviewed retrospectively regarding the operation time, preoperative and postoperative intraocular pressure, visual acuity and astigmatism for 54 consecutive patients who received a 23G releasable suture vitrectomy and for 98 consecutive patients who received a 20G conventional vitrectomy during the period between April 2007 and September 2010.

RESULTS

Mean operation time based on the operation record was 88.5 ± 20.1 minutes in the 23G releasable suture vitrectomy group and 102.1 ± 23.1 minutes in the 20G conventional vitrectomy group, respectively (p = 0.01). The last best-corrected visual acuity (BCVA) was significantly better than the preoperative BCVA in both patient groups (p = 0.01, p = 0.01). The 23G releasable suture group showed less surgically induced astigmatism than the 20G conventional vitrectomy group. Vitreous bleeding was observed to be in 6 eyes (5.9%) in the 23G group, and in 8 eyes (8.2%) in the 20G group. In addition, ocular hypertension was noted to be in 3 eyes (3.0%) in the 23G group, and 6 eyes (6.1%) in the 20G group. No serious complications such as postoperative hypotony or endophthalmitis were observed in either group.

CONCLUSIONS

The 23G releasable suture technique is as effective as the 20G conventional technique and offers several advantages.

Study of intraocular pressure after 23-gauge and 25-gauge pars plana vitrectomy randomized to fluid versus air fill

PURPOSE

To determine if a difference in intraocular pressure (IOP) exists after small-gauge pars plana vitrectomy randomized to fluid versus 80% sterile air fill.

METHODS

Ninety-two eyes undergoing 23-gauge and 25-gauge transconjunctival pars plana vitrectomy were randomized to fluid versus air fill, and IOP was measured at 5 different time points.

RESULTS

There is no difference in the mean IOP for eyes undergoing small-gauge pars plana vitrectomy randomized to fluid versus air fill after vitrectomy. Using 23-gauge instrumentation, the mean immediate and 2-hour postoperative IOPs were statistically lower than the mean preoperative IOP. The mean Postoperative Day 1 and Week 1 IOPs were statistically higher than the mean immediate postoperative IOP. Using 25-gauge instrumentation, the mean IOP was not statistically different at any time points in the 2 groups. When comparing 23-gauge with 25-gauge instrumentation, the immediate postoperative IOP was statistically lower and the rate of suture closure for sclerotomies was higher for 23-gauge vitrectomy.

CONCLUSION

When performing 23-gauge or 25-gauge pars plana vitrectomy, there was no difference in mean IOP for fluid- versus air-filled eyes. However, the mean IOP in the immediate postoperative period was statistically lower, and there was a higher rate of suture closure for 23-gauge compared with 25-gauge instrumentation.

Miyake-Apple view of inner side of sclerotomy during microincision vitrectomy surgery

PURPOSE

To examine the inner surface of the sclerotomy during microincision vitrectomy surgery by Miyake-Apple view.

METHODS

The anterior half of porcine eyes was attached to a transparent acrylic plate with cyanoacrylate glue. Then, either a 23-gauge or a 25-gauge trocar-cannula was inserted through the sclera obliquely. The inner surface of the entrance site was observed posteriorly by Miyake-Apple view. These images were compared with the endoscopic view of two patients who underwent vitreous surgery for an epiretinal membrane.

RESULTS

When the trocar-cannula was inserted obliquely, the Miyake-Apple view showed that the ciliary epithelium at the sclerotomy site was stretched. When the trocar-cannula was inserted vertically, the ciliary epithelium was folded, and the folds remained even after the trocar was removed. Vitreous strands were seen incarcerated into the sclerotomy site. In human eyes, a folding of the ciliary epithelium was not clearly seen with the endoscopic view but the incarcerated vitreous was seen.

CONCLUSION

The Miyake-Apple view provided a precise, in vivo, observation of the inner surface of the entry site. It disclosed the morphological stress on the ciliary epithelium by the sclerotomy.

Advantages and limitations of small gauge vitrectomy

Small gauge vitrectomy utilizing 23- and 25-gauge instrumentation has definite advantages, but also limitations, due to the physics of smaller instruments and sutureless surgery. Higher infusion and aspiration pressures are needed to remove the vitreous using 23- and 25-gauge probes. The advantages include decreased surgical times, less tissue manipulation, reduced inflammation and pain postoperatively with more rapid visual recovery. A disadvantage is greater instrument flexion than 20-gauge probes, making small gauge vitrectomy more appropriate for indications such as vitreous opacities, epiretinal membranes, macular holes, and simple retinal detachments. There are also some increased complications related to small gauge vitrectomy, including dislocation of cannulas intraoperatively, early postoperative hypotony, choroidal detachment, and possibly an increased risk of infectious endophthalmitis.

[Three-dimensional visualization of sclerotomies with ultrasound biomicroscopy. Comparison of 20 and 23 gauge incisions on the porcine eyeball]

BACKGROUND

When pars plana vitrectomy is performed, the sizes of the sclerotomy cannula vary between 20 and 23 gauge. We examined the morphology of the scleral tunnels by ultrasound biomicroscopy additionally taking into account the incision angle.

MATERIAL AND METHODS

In each of 16 enucleated porcine eyes three 20 or 23 gauge sclerotomies with varying angles between 30 and 90° to the horizontal level were performed. The vertical 20 gauge sclerotomies were additionally sealed by 7.0 vicryl cross-stitching. The resulting scleral channels were analysed by 3-D ultrasound biomicroscopy.

RESULTS

The sclerotomies were echographically detectable in all cases. Analysis revealed that the sutured straight 20 gauge tunnels were hyporeflective in only some parts while the other incisions showed continuous hyporeflectivity along the complete channel in many cases. The smaller the instruments used and the flatter the scleral angles chosen, the smaller were the measured widths of the incision tunnels.

CONCLUSION

Imaging sclerotomies ex vivo by ultrasound biomicroscopy is reliably reproducible. In the echographic pictures straight 20 gauge incisions appeared to be safely sealed by the sutures while the nonsealed tunnels often showed continuous patency. By choosing small instruments and flat incision angles the width of the resulting scleral channels can be reduced.

Effect of operative field irrigation on intraoperative bacterial contamination and postoperative endophthalmitis rates in 25-gauge vitrectomy

PURPOSE

The purpose of this study was to compare bacterial contamination and endophthalmitis rates with different irrigation methods in 25-gauge vitrectomy.

METHODS

A total of 4,347 eyes undergoing 25-gauge vitrectomy were studied prospectively. Of these, 2,801 eyes were irrigated with infusion fluid (group A) and 1,546 with 1.25% povidone-iodine (group B) after lid speculum placement. Bacteriologic culture was performed for 103 eyes in group A and 155 eyes in group B using the following samples: ocular surface fluid after placement of the lid speculum (left eye 1), ocular surface fluid after operative field irrigation (left eye 2), vitreous collected after angled incision made while some irrigation fluid remains in the conjunctival sac (V1), and vitreous at the completion of vitrectomy (V2).

RESULTS

The bacterial contamination rate in left eye 1 did not differ significantly between groups A (5.5%) and B (5.8%). However, the rates in left eye 2, V1, and V2 were lower in group B (0%, 0%, and 0.6%, respectively) than in group A (2.0%, 1.0%, and 2.0%). Incidences of endophthalmitis were 0 of 2,801 eyes and 0 of 1,546 eyes in groups A and B, respectively.

CONCLUSION

After lid speculum placement, ocular surface contamination occurred in approximately 6% of eyes. Irrigating the operative field again with 1.25% povidone-iodine and performing sclerotomy with some povidone-iodine remaining in the conjunctival sac prevented bacterial contamination of the vitreous.

Polyethylene glycol hydrogel polymer sealant for closure of sutureless sclerotomies: a histologic study

PURPOSE

To evaluate a polyethylene glycol-based hydrogel bandage for its ability to secure sutureless pars plana vitrectomy sclerotomies.

DESIGN

Laboratory investigation.

METHODS

Twenty-gauge (20-G) and twenty-three gauge (23-G) sclerotomies were constructed in human cadaveric eyes. A total of 24 sclerotomies were constructed in 6 eyes. Four sclerotomies per eye were constructed. Two were straight 20-G incisions, of which 1 was sutured and 1 was covered with the bandage. The other 2 were 23-G beveled incisions, of which 1 was left bare and the other was closed with the hydrogel bandage. India ink was applied over the sclerotomy sites while the intraocular pressure (IOP) was varied. The presence of India ink particles along incisions was evaluated by histologic analysis.

RESULTS

The hydrogel bandage prevented the entry of ink particles in all covered incisions after IOP modulation and incision manipulation. One 20-G sutured incision showed partial ink ingress. Four uncovered 23-G incisions showed the presence of ink within the inner aspect of the incisions (P = .0455 relative to 23-G sealed incisions). Twenty-two out of 24 incisions were evaluated, as 2 incisions could not be identified on histologic analysis.

CONCLUSIONS

The use of a hydrogel bandage to close sutureless sclerotomies is a practical alternative to sutures. Closure of sutureless sclerotomies may reduce the entry of ocular surface fluid into these incisions as well as prevent leakage of intraocular fluid in the immediate postoperative period. Incision closure may reduce the incidence of postoperative endophthalmitis and hypotony in sutureless vitreous surgery.

A 27-gauge instrument system for transconjunctival sutureless microincision vitrectomy surgery

OBJECTIVES

To evaluate the efficiency, preliminary safety, and feasibility of a 27-gauge instrument system for transconjunctival microincision vitrectomy surgery (MIVS) in a variety of vitreoretinal diseases.

DESIGN

Experimental, interventional case series.

PARTICIPANTS

Thirty-one eyes (31 patients) underwent a variety of vitreoretinal procedures using the 27-gauge transconjunctival MIVS system to treat epiretinal membrane (n = 10), idiopathic macular holes (n = 7), diabetic vitreous hemorrhage (n = 5), vitreous opacity with suspicion of intraocular lymphoma (n = 4), focal diabetic traction retinal detachment (n = 3), macular traction syndrome (n = 1), and macular edema secondary to central retinal vein occlusion (n = 1).

METHODS

We developed a 27-gauge instrument system that includes an infusion line, a high-speed vitreous cutter, an illumination system, and a variety of vitreoretinal instruments, such as membrane forceps and sharp-tipped endophotocoagulation probes. The duty cycle of the 27- and 25-gauge cutters was measured for several cut rates using a high-speed imaging camera. Infusion and aspiration rates were measured using balanced saline solution (BSS) and porcine vitreous with different aspiration levels. Surgical outcomes, including anatomic success, visual outcomes, operating times, and intraoperative and postoperative complications, were evaluated.

MAIN OUTCOME MEASURES

Duty cycle of cutters, infusion and aspiration rates, and surgical results of 27-gauge vitrectomy.

RESULTS

Although the infusion and aspiration rates of the 27-gauge system measured in BSS were reduced to an average of 62% and 80%, respectively, compared with those of the 25-gauge system, the duty cycle of the 27-gauge cutter, 61% at 1000 cpm and 38% at 1500 cpm, was equal to or better than those of the 25-gauge cutter (62% and 28%, respectively). Analysis of the fluid dynamics showed that vented gas-forced infusion can be set to range from 20 to 30 mmHg to control intraocular pressure (IOP) during 27-gauge vitrectomy. Anatomic success was achieved in all study eyes (100%); 20 eyes (65%) had visual improvement of 3 lines or more. No eyes required conversion to larger gauge instrument. All sclerotomies self-sealed without hypotony (IOP < or = 7 mmHg) from 1 day postoperatively.

CONCLUSIONS

Although the fluid dynamics and cutting efficiency of 27-gauge instruments are lower compared with 25-gauge MIVS, the 27-gauge system is feasible and may reduce concerns about wound sealing-related complications in selected cases.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.