Vitrectomy Machines Research Articles

Efficacy of Novel Endoillumination Assisted Modified Scleral Buckling versus Conventional Scleral Buckling

Scleral buckling (SB) has proven to be an effective surgical technique for RRDs especially in patients with uncomplicated rhegmatogenous retinal detachment (RRD) not associated with proliferative vitreoretinopathy (PVR). Until recently, it was still the most commonly employed surgical technique in dealing with RRDs with a high success rate. with the advent of the modern retinal viewing systems and vitrectomy machines, the trends in dealing with RRD are more inclining towards pars plana vitrectomy. Possible reasons for it are that conventional SB has steeper learning curve and it is assisted by the Indirect ophthalmoscope to view the retina during various steps of the surgery which has smaller inverted image and also its use is cumbersome. with the novel techniques being introduced, the essence of scleral buckling can be preserved and the surgical technique can be made much easier by providing a better viewwith easy localization of retinal breaks. The basic principles and steps of conventional scleral buckling can be well taught and more effectively practiced with the introduction of better illumination and viewing systems. In this study, the efficacy of endoillumination source assisted modified scleral buckling would be determined and compared with the results of conventional scleral buckling. Objective: To compare the functional and anatomical success rates of conventional scleral buckling for RRD with endo-illumination assisted Wide angle viewing system modified scleral buckling in patients with uncomplicated rhegmatogenous retinal detachment. Materials and Methods: This is an interventional prospective study being conducted at the Department of Ophthalmology, Peshawar Medical College (PMC) and Allied hospitals from July 1, 2020 to December 31, 2020. The study included 40 patients presenting with uncomplicated RRD, 20 in each group, by simple random sampling technique. Outcome measures assessed were primary visual acuity (VA), primary anatomical success, and peri-operative complications. Results: 40 patients (40 eyes) were recruited in this study, 20 in each group (conventional scleral buckling group and modified scleral buckling group), who completed a 3 months follow up. 21 (52.5%) were male patients while 19 (47.5%) patients were female. Mean age was 44.3 ± 12.1. New retinal breaks were identified in 3(15%) patients in the MSB group. Retinal reattachment was achieved in 95% patients in both the groups. Cataract Progression was later found in 1(5%) patient in the MSB group. No other complications were recorded in either of the comparative groups. 1(5%) patient each, in both the groups, underwent additional surgeries. Conclusion: In conclusion, the endolight-assisted scleral buckling using a wide angle visualization system appears to be a promising technique with comparable surgical outcomes to conventional scleral buckling with least complications in specific cases of rhegmatogenous retinal detachment. It can be safely used to meet the surgical need and reduce discomfort during surgery. It is particularly useful in cases with pre-operatively undetected retinal tears. Wide angle viewing system assisted modified scleral buckling technique is highly recommended for teaching purposes. Keywords: Scleral buckling; Wide angle viewing system, Rhegmatogenous retinal detachment, Modified scleral buckling.

Managing PVR in the Era of Small Gauge Surgery.

Proliferative vitreoretinopathy (PVR) is the leading cause of failed rhegmatogenous retinal detachment (RRD) surgery. Based upon the presence of clinical features and due to associated underlying risk factors, it is classified into various grades based upon its severity and extent of involvement. Despite excellent skills, flawless techniques, and high-end technology applied in the management of RRD, PVR still occurs in 5–10% of cases. Due to the advancements in wide angle viewing systems, advance vitrectomy machines and fluidics, early identification, use of long-term heavy silicon oil tamponades, high-speed cutters, small-gauge vitrectomies, use of perfluorocarbon liquid (PFCL), and small-gauge forceps and scissors, the success rate in the management of PVR has increased leading to improved anatomical outcomes. However, functional outcomes do not correlate well with improved anatomical outcomes. Various complications occur after RRD repair that are responsible for re-retinal detachment and recurrence of PVR. This article highlights causes, risk factors, classification, grading, diagnosis, and approach to management of PVR and post-PVR surgery complications.

In Vitro Comparison of Various High-Speed Vitrectomy Machines Using Dual Blade Cutters.

ObjectivesThe objective of this study is to compare various dual blade vitrectomy cutters for their efficiency in an in vitro setting.MethodsIn this in vitro experimental study, we compared various vitrectomy systems including EVA (Dutch Ophthalmic Research Center, Zuidland, The Netherlands), REVOLUTION (Optikon 2000, Inc., Rome, Italy), and OS4 (Oertli Instrumente AG, Berneck, Switzerland) in terms of efficiency in vitreous cutting and aspiration for various vitreous substitutes. These substitutes included water, chicken egg albumin, and goat vitreous. We only used 23-gauge dual blade cutters across all platforms to maintain uniformity. The cutting and aspiration efficiency was measured across various cut and vacuum settings of vitrectomy machines and measured as mass aspirated in a given time. Data analysis included comparing the amount of mass aspirated by these machines at preset cut and vacuum settings.ResultsScatter plots showed a comparable mass of water aspirated by the EVA and REVOLUTION at 1000 to 5000 cuts per minute at a constant vacuum of 500 mm Hg whereas OS4 aspirated lesser mass at similar settings. Same trends were noted for goat vitreous for EVA and REVOLUTION but aspirated mass of albumin fluctuated widely across various platforms. At peak machine settings, REVOLUTION showed superiority across all three vitreous models due to its higher peak settings. The area under curve (AUC) analysis showed no significant differences among machines for water and goat vitreous at comparable settings but results were fluctuating for egg albumin.ConclusionEmploying higher cut rates for dual blade cutters results in better efficiency of vitrectomy machines.

In Vivo Intraocular Pressure Monitoring during Microincision Vitrectomy with and without Active Control of Infusion Pressure

To evaluate intraocular pressure (IOP) fluctuation during vitrectomy, we directly monitored IOP in vivo using 2 vitrectomy machines with or without constant infusion pressure monitoring and control. Among 61 eyes of 61 consecutive patients, 32 were assigned to the Accurus system (group 1) and 29 were assigned to the Constellation system (group 2) in this prospective case series. The IOP fluctuations were evaluated during routine vitrectomy procedures. The initial IOP before vitrectomy was 20.3 ± 2.4 mm Hg in group 1 using a conventional vented gas forced infusion system and 20.0 ± 0.0 mm Hg in group 2 using active IOP control at 20 mm Hg (p = 0.532). However, the average IOP change during core vitrectomy was -8.6 ± 4.3 mm Hg in group 1 and -0.8 ± 1.1 in group 2 (p<00.001). Maximum IOP was significantly decreased in group 1 (-17.0 ± 2.6 mm Hg) compared with that in group 2 (-4.1 ± 2.2 mm Hg) (p<00.001). Partial ocular collapse was observed during vitrectomy only in group 1 (78.1%). Peak IOP significantly increased during scleral compression and gas and fluid injection but was not significantly different between the groups (all p≥0.147). The IOP fluctuation range was 50-70 mm Hg in both groups. The IOP fluctuated significantly during routine vitrectomy using both systems. Hypotony and partial ocular collapse were more frequently observed during vitrectomy with the Accurus system than with the Constellation system. Both systems were vulnerable to IOP surge during indentation and intravitreal injection.

Innovations in pediatric cataract surgery.

Advances in technology have made surgery in children safer and faster. The management of pediatric cataract has made rapid progress in the past decade with the availability of safer anesthesia, newer technique's, more predictable intraocular lens (IOL) power calculation, a better understanding of neurobiology, genetics, amblyopia management, improved IOL designs for preventing visual axis opacification, and adjuvant postoperative care. Modern vitrectomy machines with minimally invasive instruments, radiofrequency, diathermy, and plasma blades help immensely in complicated cases. Preoperative evaluation with ultrasound biomicroscopy and optical coherence tomography (OCT) allows better planning of surgical procedure. The future holds good for stem cell research, customized OCT, and Zepto (precision pulse capsulotomy).

Author′s Response: Maximizing the visual outcome in traumatic cataract cases: The value of a primary posterior capsulotomy and anterior vitrectomy

Dear Sir, First of all we are thankful to you for your interest and inputs. Primary posterior capsulotomy and vitrectomy procedure done in the absence of poster capsular tear is a special procedure by vitreo rhexis. It is not only to prevent capsular opacification, but to avoid secondary cataract and recurrent inflammation of anterior vitreous.[1,2] Erie et al. reported incidence of retinal detachment in case of the posterior capsular rent in case of normal cataract, this study is all about traumatic cataract so normal and post trauma cataracts are not comparable.[1,2,3] With the emergence of high speed vitrectomy machines and cutters, incidence of iatrogenic break and retinal detachment following shallow anterior vitrectomy is minimal.[4,5] Nd: YAG may cause may cause increase incidence of retinal break and retinal detachment.[6] The primary objective of this study was to study the effect of primary posterior capsulotomy on final visual outcome in the case of traumatic cataract.[1,2] It is important to have long-term follow-up, but this study is about traumatic cataract, trauma may have many co morbidities, which may also cause damage other than posterior capsulotomy.[2] We may follow-up these cases way forward for a longer period.

27-Gauge vitrectomy.

Ten years or more have passed since the current concept of 25-gauge transconjunctival sutureless vitrectomy with a trocar-cannula system emerged. There is no doubt that current microincision vitrectomy surgery with 25- or 23-gauge instrumentation has simplified the vitrectomy procedure and has provided numerous potential advantages over traditional 20-gauge surgery. The established theory regarding surgical wounds is that 'much smaller is better'. Along with the development of new-generation vitrectomy machines with ergonomic instruments, surgeons have been shifting dramatically from 20-gauge systems to 23- and 25-gauge systems over the last years. Thanks to recent innovations and improvements in high-end multifunctional vitrectomy machines and ultrahigh-speed cutters, the development of powerful light sources, and wide-angle viewing systems, several new techniques have also encouraged us to launch the development of a 27-gauge vitrectomy system over the past several years. Similar to the recent evolution in 23- and 25-gauge systems, further development and refinement of the functionality of instruments with a gauge of 27 or more are under way and will continue over the coming years, which in the future will allow us to establish this system for ultra-minimally invasive surgery for the full spectrum of vitreoretinal pathologies.

Machines and cutters: VersaVIT - potential and perspectives of office-based vitrectomy.

The concept of office-based vitrectomy has been a topic for several years; however, the large size of the vitrectomy machines has limited the options for many years. Today, though, smaller machines can offer adequate performance regarding vitrectomy. As a result, we can now make more arguments for this type of surgery to be performed in the office environment, despite the limitations these machines may still have.

Perspective on Fluid and Solid Dynamics in Different Pars Plana Vitrectomy Systems

To summarize current concepts and recent data from the literature about different vitrectomy machines and small-gauge systems based on physical laws. Interpretive essay. Review and synthesis of selected recent literature with interpretation and perspective. Pars plana vitrectomy can be performed with a wide variety of treatment strategies, for multiple diseases, and with different materials (solids and fluids). We discuss a variety of machines and system settings (peristaltic pump, duty cycle, aspiration, and infusion controls) targeting safer and the most effective surgery with detailed explanations of the physical properties. Effective management of new surgical strategies is based on recognizing and addressing various physical characteristics in disease and ocular settings. Although the properties of machine are expanding, the long-term efficacy and safety of most new approaches have yet to be established in controlled clinical trials.

Technological Advances in Pediatric Cataract Surgery

Purpose: Managing pediatric cataracts is often challenging. It is technically difficult to perform surgery in these small complaint eyes and there is higher prevalence of postoperative complications. The outcomes of surgery depend on technique and technology. The purpose of this study is to review the current literature on technological advances in pediatric cataract surgery. Methods: Review of literature on management of pediatric cataract surgery. Results: The advent of vitrectomy machines and intraocular lenses (IOLs) has revolutionized pediatric cataract surgery. “Vitrectorhexis” has become a good alternative to manual capsulorhexis. Primary management of posterior capsule and limited anterior vitrectomy has reduced the incidence of visual axis opacification. Primary IOL implantation is becoming a standard of care in the youngest children. Single piece Acrysof® is preferred for in-the-bag implantation and 3-piece Acrysof® for sulcus implantation. Newer IOLs are being evaluated in pediatric eyes. Precise measurement of intraocular lens power and predicting refractive change are major challenges in long term care of children after surgery. Conclusion: New technology and surgical techniques have refined pediatric cataract surgery. It is critical to focus our efforts on precise biometry measurements, IOL power calculation, and designing IOLs that may address refractive changes in the growing pediatric eye.

The Expanding Role of Primary Pars Plana Vitrectomy in the Treatment of Rhegmatogenous Noncomplicated Retinal Detachment

The surgical management of rhegmatogenous retinal detachment has evolved dramatically during the past 2 decades. Investigators have introduced and refined alternative techniques to scleral buckling surgery including pneumatic retinopexy and primary pars plana vitrectomy (PPV). Rapid parallel developments in instrumentation, including wide-angle viewing systems, perfluorocarbon liquids, novel vitrectomy machines, intraocular tamponades, and endolaser photocoagulators have led to increasing sophistication in primary PPV surgical techniques for the treatment of rhegmatogenous uncomplicated retinal detachment. However, the precise role of primary PPV in new uncomplicated retinal detachment remains debatable owing to the lack of controlled randomized trials. This article examines primary vitrectomy treatment for rhegmatogenous uncomplicated retinal detachment and presents the specific types of retinal detachments for which primary PPV may be optimal, according to personal and reported results, the surgical instrumentation and technique, as well as the complications and limitations of this surgical method

Evaluation of Vitrectomy Machines as a Source of False-Positive Culture Contamination in Endophthalmitis

We sought to determine whether a venturi-aspiration vitrectomy machine could contaminate a vitrectomy culture. Ninety vitrectomies were simulated in a hospital operating room and were cultured with standard techniques. An additional 90 control specimens were cultured in the exact same manner, but the vitrectomy machine was not used. Instead, the control specimens were placed directly into a sterile vitrectomy cassette. Contamination rates in the two groups were compared. Contamination occurred in four of 90 vitrectomy-simulation cultures and in three of 90 control cultures. This difference in contamination rate was not statistically significant. Although the result of a culture of the vitrectomy effluent can be false-positive, the source of contamination is not likely to be the vitrectomy machine.