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

Vitrectomy and ILM peeling in rhesus macaque: pitfalls and tips for success

BACKGROUND

The non-human primate (NHP) model is ideal for pre-clinical testing of novel therapies for human retinal diseases due to its similarity to the human visual system. However, intra-ocular delivery of gene therapy or cell transplantation to the retina gets hampered by the sticky vitreous body and poorly permeable inner limiting membrane (ILM) in primates. Although vitrectomy and ILM peeling are commonly performed in patients, many pitfalls exist in carrying out these procedures in the rhesus macaque, which have not been reported previously.

METHODS

We summarised common surgical pitfalls after performing vitrectomy and ILM peeling in four eyes of two rhesus macaques (one male and one female). We provided corresponding hands-on technical tips based on our surgical experience and literature search. Orbital CT scans were compared between adult rhesus macaques and humans. High-resolution surgical videos were recorded to demonstrate each critical surgical step.

RESULTS

Due to size difference, poor post-operative compliance, and high-standard requirements of a controlled experiment, there were eleven common surgical pitfalls during vitrectomy and ILM peeling in rhesus macaque. Falling into these pitfalls may produce discomfort, add fatigue, cause surgical complications, or even lead to the exclusion of the NHP from an experimental group.

CONCLUSION

Recognition and circumvention of these pitfalls during vitrectomy and ILM peeling in NHP are essential. By focusing on these surgical pitfalls, we can better carry out preclinical tests of novel therapies for retinal diseases in the NHP model.

Pars Plana Vitrectomy Port Sizes: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND OBJECTIVE

The uptake of small-gauge (SG; ie, 23-gauge [23-G], 25-gauge [25-G], and 27-gauge [27-G]) pars plana vitrectomy (PPV) has grown. We aim to investigate the advantages and disadvantages of various PPV port sizes in a meta-analysis of randomized controlled trials (RCTs).

MATERIALS AND METHODS

A systematic literature search was performed for RCTs comparing PPV port sizes for any indication. Weighted mean differences (WMDs) and risk ratios (RRs) were calculated, and meta-analysis was performed with random-effects models.

RESULTS

A total of 1,678 eyes from 22 RCTs were included. Risk-of-bias assessment found some concerns in 13 studies. Compared with 20-gauge PPV, there was no significant difference in the final or change in best-corrected visual acuity (BCVA; five studies analyzed each) relative to that of SG PPV. SG PPV was associated with a significantly greater incidence of hypotony (RR = 3.79; 95% confidence intervals [CI], 2.02 to 7.10; P < .0001; six studies) and choroidal detachment (RR = 5.65; 95% CI, 1.01 to 31.71; P = .05; three studies). Compared with 25-G PPV, there was no significant difference in BCVA at any time point with 23-G (two studies), and significantly more frequent port suturing was required with 23-G (RR = 0.46; 95% CI, 0.25 to 0.84; P = .01; two studies). Compared with 25-G PPV, 27-G was associated with a significantly better final BCVA (WMD = -0.06 logMAR; 95% CI, -0.11 to -0.01; P = .02; five studies) and a significantly lengthened surgery (WMD = 4.11 minutes; 95% CI, 0.18 to 8.05; P = .04; three studies).

CONCLUSIONS

There was no significant difference in visual or surgical outcomes following 20-gauge PPV relative to SG PPV (Grading of Recommendations, Assessment, Development, and Evaluation recommendation: low certainty), and there was an increased risk of postoperative complications with SG PPV (moderate certainty). Compared with 25-G PPV, 23-G required more frequent port suturing (moderate certainty), whereas 27-G may be associated with a better final BCVA but longer surgery (low and moderate certainty, respectively). [Ophthalmic Surg Lasers Imaging Retina. 2022;53:152-158.].

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.

Clinical comparison of 27-gauge and 23-gauge instruments on the outcomes of pars plana vitrectomy surgery for the treatment of vitreoretinal diseases

PURPOSE OF REVIEW

To compare outcomes of 27-gauge and 23-gauge pars plana vitrectomy (PPV) for treatment of vitreoretinal diseases.

RECENT FINDINGS

Sixty-eight patients undergoing microincisional PPV for treatment of vitreoretinal diseases were randomized 1 : 1 to 27-gauge or 23-gauge surgery with a 7500 cuts-per-minute vitrectomy probe. The most common reasons for vitrectomy were epiretinal membrane (49%) and vitreous hemorrhage (24%). Mean ± standard deviation (SD) changes from immediate preoperative to immediate postoperative intraocular pressure were -0.40 ± 6.60 mmHg in the 27-gauge and -3.05 ± 7.64 mmHg in the 23-gauge group (adjusted mean difference 2.42 mmHg, 95% lower confidence limit 0.64, P = 0.013), but these changes were not associated with primary reason for vitrectomy (P = 0.065). Mean ± SD conjunctival edema grades in the 27-gauge and 23-gauge groups 1 week after surgery were 0.02 ± 0.124 and 0.10 ± 0.246, respectively (least squares mean difference -0.09, 95% upper confidence limit -0.03, P = 0.004), and were 0.01 ± 0.122 and 0.12 ± 0.338, respectively, at the probe incision site. Conjunctival edema grades were similar in both groups at 1 and 3 months. Mean ± SD pain ratings on postoperative day 1 - an indicator of patient comfort - were similar in the two groups.

SUMMARY

Smaller diameter vitrectomy instruments are associated with smaller reductions in immediate postoperative intraocular pressure.

Comparison of postoperative ciliary body changes associated with the use of 23-gauge and 20-gauge system for pars plana vitrectomy

Background

To compare the ciliary body changes associated with the use of 23-gauge (23G) and 20-gauge (20G) systems for pars plana vitrectomy.

Methods

A total of 60 patients (60 eyes) with idiopathic epiretinal membrane who were scheduled for surgical treatment were selected and randomly assigned to 20G group or 23G group. Time required for incision making, vitrectomy, and incision closure was compared between the two groups. Changes in ciliary body were evaluated by ultrasound microscopy (UBM). Anterior chamber inflammation was assessed with laser flare meter instrument.

Results

Incision-making time (4.5 ± 0.9 min) and incision-closure time (2.8 ± 0.7 min) in the 23G group were significantly shorter than those in the 20G group (10.1 ± 1.5 min and 11.3 ± 2.2 min, respectively). No significant intergroup difference was observed with respect to time required for vitrectomy (21.6 ± 3.3 min and 20.7 ± 3.2 min, respectively). Ciliary body thickness in the 23G group recovered back to preoperative levels after 4 weeks, as against 8 weeks in the 20G group. Postoperative ciliary body thickness in the 20G group was significantly higher than that in the 23G group (p < 0.05). The aqueous protein concentration in 23G group recovered back to preoperative levels after 2 weeks, as against 4 weeks in the 20G group. Postoperative aqueous protein concentration in the 20G group was significantly higher than that in the 23G group (p < 0.05).

Conclusions

The use of 23G system was associated with significantly milder injury to the ciliary body as compared to that associated with the use of 20G system.

Trial registration

The study was retrospectively registered on Chinese Clinical Trial Registry. The clinical study registration number was ChiCTR-INR-17011082. Date of registration: 2017-04-07.

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.

Small-Gauge Pars Plana Vitrectomy With SF6 Gas for the Repair of Primary Rhegmatogenous Retinal Detachment With Multiple Breaks

BACKGROUND AND OBJECTIVE

To compare outcomes of 25-gauge pars plana vitrectomy (PPV) and sulfur hexafluoride (SF6) gas for primary rhegmatogenous retinal detachment (RRD) associated with multiple-quadrant versus single-quadrant breaks.

PATIENTS AND METHODS

A retrospective study of patients with RRD who underwent 25-gauge PPV with breaks involving multiple quadrants (Group A) or versus a single quadrant (Group B).

RESULTS

One hundred eighteen eyes of 118 patients with a mean age of 60.4 years ± 11.8 years were reviewed, 27 with multiple-quadrant breaks and 91 with single-quadrant breaks. Single surgery anatomical success was achieved in 92.6% of Group A versus 93.4% of Group B patients (P = .88). The location and number of quadrants did not account for the variation in single surgery success or visual outcome.

CONCLUSIONS

RRD with multiple-quadrant breaks is not associated with worst outcomes than single-quadrant breaks when treated with 25-gauge PPV and SF6 gas. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:820-827.].

Evaluation of mechanical closure resistance of sutureless vitrectomy sclerotomies after conjunctival cauterization with bipolar diathermy forceps

BACKGROUND

Suturing is the most widely used technique to close leaking sclerotomies after transconjunctival sutureless vitrectomy (TSV). However, with the aim of avoiding the disadvantages caused by conjunctival stitches, there have been described other closure techniques, such as the cauterization of the conjunctiva placed over the incisions. To continue advancing knowledge of the incisional occlusion effect achieved by conjunctival diathermy, it would be also interesting to study the wound closure resistance obtained under intraocular pressure (IOP) changes, given that in the early postoperative period eyes are subjected to pressure stress. In our study, we compare the mechanical resistance observed in sclerotomies treated with bipolar diathermy after TSV compared to that found in incisions in which cauterization was not performed.

METHODS

This was an experimental, randomized, and observer-masked study in which 23-gauge TSV was performed in 80 cadaveric pig eyes. Once each vitrectomy was finished, cauterization was performed with bipolar diathermy forceps on the conjunctiva placed over one of the superior sclerotomy sites; no maneuver was performed over the other superior incision. IOP was gradually increased by means of the vitrectomy system (Accurus; Alcon Laboratories, TX) until one of the superior sclerotomies opened, allowing internal ocular solution to escape.

RESULTS

In 35 % of cases (28 of 80 eyes), sclerotomies subjected to diathermy allowed intraocular fluid escape first (p = 0.01). When comparing opening pressure values, cauterized incisions leaked at significantly higher pressure levels than those in which diathermy was not applied (p < 0.001).

CONCLUSIONS

Bipolar diathermy on sutureless sclerotomies has demonstrated to be, in our experimental model, an effective method for increasing the sclerotomy closure resistance. Although its use in vitrectomized eyes has previously been described, our study is the first to analyze the response of cauterized sclerotomies to IOP increases.

Comparison of Clinical Features After 20-Gauge Vitrectomy Versus 23-Gauge Vitrectomy

PURPOSE

To compare the clinical features after 20-gauge (20G) versus 23-gauge (23G) pars plana vitrectomy (PPV).

DESIGN

This was a prospective observational study.

METHODS

Patients who underwent 20G or 23G PPV participated in the study. Sutures were used in all patients who had 20G and as necessary in patients who had 23G. All patients were examined with ultrasound biomicroscopy and tonometry for intraocular pressure (IOP) preoperatively and postoperatively at 1 day, 1 week, 1 month, and 6 months.

RESULTS

Forty-nine eyes underwent 20G PPV and 97 eyes underwent 23G PPV. Hypotony appeared more frequently in the 23G group (9 patients of 97, 9%) than in the 20G group (1 patient of 49, 2%) 1 day after surgery. Mean IOP was statistically significantly lower in the 23G group 1 day after surgery (P = 0.000). Postoperatively, choroidal detachment (CD) was found in both the 23G group (22/97, 23%) and the 20G group (1/49, 2%). In the 23G group, the mean IOP of eyes with CD was significantly lower than those without CD. There was no statistically significant difference in vitreous incarceration between the 2 groups (P = 0.317).

CONCLUSIONS

Choroidal detachment and hypotony were common complications in the early stages after 23G PPV. The incidence of postoperative vitreous incarceration was similar in both groups.

Surgical complications of primary rhegmatogenous retinal detachment: a meta-analysis

BACKGROUND

To investigate the surgical complications of scleral buckling (SB) and pars plana vitrectomy (PPV) performed on primary rhegmatogenous retinal detachment (RRD) and to discover which surgical procedures bring fewer complications.

METHODS

An electronic literature search using the PubMed database, ISI Web of Knowledge and the Cochrane Central Register of Controlled Trials to identify randomized controlled trials and observational studies comparing SB with PPV on primary RRD. Outcome measures included intra-operative complications and early and late post-operative complications.

RESULTS

During the operation, significantly less subretinal hemorrhage occurred in the PPV group than in the SB group (OR = 4.71; 95%CI, 1.33-16.64; p = 0.02) and the hypotony incidence was significantly higher in the SB group (OR = 18.24; 95%CI, 2.37-140.44; p = 0.005); however, the occurrence of iatrogenic breaks was significantly lower in the SB group (OR = 0.05; 95%CI, 0.01-0.21; p<0.0001). In the early stage of post-operation, significantly higher incidence of choroidal detachment was identified in the SB group than in the PPV group (OR = 10.19; 95%CI, 2.36-44.09; p = 0.002); patients undergoing SB had significantly higher odds of residual subretinal fluid (OR = 14.71; 95%CI, 1.84-117.32; p = 0.01); the occurrence of high intraocular pressure was significantly lower in the SB group (OR = 0.46; 95%CI, 0.23-0.89; p = 0.02); and no significant difference was shown in the incidence of epithelia defect (p = 0.37) between the two groups. In the late stage of post-operation, the incidence of diplopia/extraocular muscle dysfunction was significantly higher in the SB group (OR = 4.04; 95%CI, 1.30-12.52; p = 0.02); and significantly less cataract was observed in the SB group (OR = 0.20; 95%CI, 0.14-0.30; p<0.00001); no significant difference was found in the incidences of cystoid macular edema (p = 0.65), macular pucker (p = 0.52), post-operative proliferative vitreoretinopathy (p = 0.73) and epiretinal membrane (p = 0.47) in other late post-operative complications.

CONCLUSIONS

This meta-analysis suggests that PPV could be considered as potential surgical management on primary RRD.

Idiopathic vitreomacular traction and macular hole: a comprehensive review of pathophysiology, diagnosis, and treatment

Posterior vitreous detachment (PVD) is a common phenomenon in the aging eye. However, this may be complicated by persistent symptomatic vitreomacular adhesions that exert tractional forces on the macula (vitreomacular traction; VMT). VMT itself may be associated with epiretinal membrane formation and the development of idiopathic macular holes (IMH). Such pathologies may cause visual disturbances, including metamorphopsia, photopsia, blurred vision, and decreased visual acuity, which impact an individual's quality of life. Technologies such as optical coherence tomography allow an increasingly more accurate visualisation of the macular anatomy, including quantification of macular hole characteristics, and this facilitates treatment decision-making. Pars plana vitrectomy remains the primary treatment option for many patients with VMT or IMH; for the latter, peeling of the inner limiting membrane (ILM) of the retina has shown improved outcomes when compared with no ILM peeling. The development of narrow-gauge transconjunctival vitrectomy systems has improved the rate of visual recovery following surgery. Ocriplasmin, by degrading laminin and fibronectin at the vitreoretinal interface, may allow induction of PVD in a non-invasive manner. Indeed, clinical studies have supported its use as an alternative to surgery in certain patient populations. However, further research is still needed with respect to greater understanding of the pathophysiology underlying the development of VMT and IMH.

Diathermy of leaking sclerotomies after 23-gauge transconjunctival pars plana vitrectomy: a prospective study

PURPOSE

To evaluate the efficacy of bipolar diathermy in ensuring closure of leaking sclerotomies after complete 23-gauge transconjunctival sutureless vitrectomy.

METHODS

In this prospective, interventional case series, in 136 eyes of 136 patients with at least one leaking sclerotomy at the end of a complete 23-gauge transconjunctival sutureless vitrectomy, external bipolar wet-field diathermy was applied to leaking sclerotomies, including the conjunctiva and sclera. Intraoperative wound closure, and postoperatively, at 6 hours, 1 day and 3 days, sclerotomies leakage, intraocular pressure, hypotony, and hypotony-related complications were evaluated.

RESULTS

Intraoperative closure was achieved in 231 of 238 leaking sclerotomies (97%) that received diathermy. One of these with postoperative leakage needed suture. Compared with baseline (14.4 ± 2.8 mmHg), mean intraocular pressure was lower at 6 hours (13.2 ± 3.8 mmHg, Tukey-Kramer P < 0.001) and not different at 24 hours or 72 hours. Hypotony (intraocular pressure <5 mmHg) was observed in 6 eyes (4.5%) at 6 hours, in 2 (1.5%) at 24 hours, and in none at 3 days. Logistic regression analysis showed that, 6 hours postoperatively, hypotony was related to younger age (≤50 years) at surgery (P = 0.031). No hypotony-related complications were recorded.

CONCLUSION

Bipolar wet-field diathermy of sutureless sclerotomies is an effective method for ensuring a leaking sclerotomies closure.

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.

Comparison of 23-gauge sutureless sclerotomy architecture and clinical outcomes in macular and non-macular surgery using spectral-domain optical coherence tomography

PURPOSE

To compare the 23-gauge (23-G) sutureless vitrectomy incision architecture in macular and non-macular surgery, using anterior segment spectral-domain optical coherence tomography (SD-OCT), and to evaluated its influence on clinical outcomes.

METHODS

A prospective, observational case series of 43 patients who underwent primary transconjunctival 23-G pars plana vitrectomy (PPV) for macular and non-macular diseases. All sclerotomy wounds were imaged 1 day after surgery using the anterior segment module of SD-OCT (OCT Spectralis; Heidelberg Engineering, Heidelberg, Germany). Sclerotomy architecture, including good wound apposition, presence of gaping and misalignment of the roof and floor of the incisions were evaluated. Preoperative, intraoperative and postoperative medical record data were also prospectively collected.

RESULTS

  Incision gaping and misalignment of the roof and floor occurred more frequently in the superotemporal and superonasal quadrants than in the inferotemporal quadrant (p < 0.05) and was more frequent in the non-macular group than in the macular group (p < 0.05). The incidence of incision gaping increased significantly as the incision angle increased. In the macular group, the mean postoperative intraocular pressure (IOP) did not change from the preoperative value, whereas in the non-macular group, the mean IOP decreased significantly from 15.09 ± 2.58 mmHg preoperatively to 12.18 ± 3.25 mmHg on the first postoperative day (p < 0.005). The mean IOP did not differ significantly between the two groups of surgery at 1 week, and at 1 month postoperatively.

CONCLUSIONS

  In 23-G PPV, non-macular surgery is associated with a significant postoperative IOP decrease in comparison with macular surgery, which could be explained by the most remodelled wound architecture.

Influence of sutureless 23-gauge sclerotomy architecture on postoperative intraocular pressure decrease: results of a multivariate analysis

PURPOSE

To evaluate the factors affecting the postoperative intraocular pressure (IOP) decrease in 23-gauge (23-G) sutureless vitrectomy, including incision architecture evaluated by anterior segment spectral-domain optical coherence tomography (SD-OCT).

METHODS

A prospective cohort study of 43 patients who underwent primary transconjunctival 23-G pars plana vitrectomy. All sclerotomy wounds were imaged 1 day after surgery using the anterior segment module of SD-OCT (OCT Spectralis, Heidelberg Engineering, Heidelberg, Germany). 23-G sclerotomy architecture, preoperative and postoperative medical data were also prospectively collected.

RESULTS

Multivariate logistic regression analysis, with backward elimination, found that surgery duration (adjusted OR = 9.17, p = 0.020) and loss of wound apposition (adjusted OR = 15.12, p = 0.022) were risk factors for significant postoperative IOP decrease (≥3 mmHg) 1 day after surgery; while age, gender, myopia, and gas tamponade were not risk or protective factors for postoperative IOP decrease.

CONCLUSIONS

In 23-G pars plana vitrectomy, the early postoperative decrease in IOP is mainly influenced by surgery duration and the self-sealing nature of the sclerotomy. The IOP decrease was not influenced by the presence or the absence of gas tamponade.