EFFECTS OF A MODIFIED VITRECTOMY PROBE IN SMALL-GAUGE VITRECTOMY: An Experimental Study on the Flow and on the Traction Exerted on the Retina

Comparison of 27-gauge beveled-tip and 25-gauge flat-tip microincision vitrectomy surgery in the treatment of proliferative diabetic retinopathy: a randomized controlled trial

PURPOSE

To compare the effectiveness and safety of a 27-gauge (27G) beveled-tip microincision vitrectomy surgery (MIVS) with a 25-gauge (25G) flat-tip MIVS for the treatment of proliferative diabetic retinopathy (PDR).

METHODS

A prospective, single-masked, randomized, controlled clinical trial included 52 eyes (52 patients) with PDR requiring proliferative membrane removal. They were randomly assigned in a 1:1 ratio to undergo the 27G beveled-tip and or 25G flat-tip MIVS (the 27G group and the 25G group, respectively). During surgery, the productivity of cutting the membrane, the number of vitrectomy probe (VP) exchanges to microforceps, total operation time, vitrectomy time and intraoperative complications were measured. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) and postoperative complications were also assessed to month 6.

RESULTS

Forty-seven eyes (47 patients) completed the follow-up, including 25 in the 27G group and 22 in the 25G group. During surgery in the 27G group, cutting the membrane was more efficient (P = 0.001), and the number of VP exchanges to microforceps was lower (P = 0.026). The occurrences of intraoperative hemorrhages and electrocoagulation also decreased significantly (P = 0.004 and P = 0.022). There were no statistical differences in the total operation time or vitrectomy time between the two groups (P = 0.275 and P = 0.372), but the former was slightly lower in the 27G group. Additionally, the 27G group required fewer wound sutures (P = 0.044). All the follow-up results revealed no significant difference between the two groups.

CONCLUSIONS

Compared with the 25G flat-tip MIVS, the 27G beveled-tip MIVS could be more efficient in removing the proliferative membrane while reducing the occurrence of intraoperative hemorrhages and electrocoagulation using appropriate surgical techniques and instrument parameters. Its vitreous removal performance was not inferior to that of the 25G MIVS and might offer potential advantages in total operation time. In terms of patient outcomes, advanced MIVS demonstrates equal effectiveness and safety to 25G flat-tip MIVS.

TRIAL REGISTRATION

The clinical trial has been registered at Clinicaltrials.gov (NCT0544694) on 07/07/2022. And all patients in the article were enrolled after registration.

Performance, safety and efficiency comparison between 10,000 and 5000 cuts per minute vitrectomy using a 25G cutter: a prospective randomized controlled study

PURPOSE

This study aims to compare the performance of the 25+® UltraVit® 5000 cuts per minute (cpm) vitrectomy probe versus the 25+ ® Ultravit 10,000 cpm® beveled tip, dual drive vitrectomy probe.

METHOD

In this prospective randomised controlled clinical trial, 52 eyes of 52 consecutive patients were randomized into either the 10,000 cpm (25 patients) or 5000 cpm vitrectomy group (27 patients). Patients were evaluated preoperatively, intraoperatively, and postoperatively on the first day, and at 1 week, 1 month and 3 months. The main outcome measures were vitrectomy time, and secondary endpoints were time to induction of posterior vitreous detachment, intraoperative complications, and number of instruments used.

RESULTS

The vitrectomy time was shorter in the 10,000 cpm group (413.7 s) compared to the 5000 cpm group (463.4 s), although there was no significant difference (p = 0.5999). One patient had an iatrogenic retinal break in the 10,000 cpm group while two patients had an iatrogenic retinal break in the 5000 cpm group. The time for posterior vitreous detachment (PVD) induction and the number of instruments used were not significantly different between the two groups.

CONCLUSION

The difference in vitrectomy times between the 10,000 cpm vitrectomy probe and the 5000 cpm cutter were not statistically significant. This may suggest that other factors affect efficiency rather than the limitations of equipment.

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.