Ophthalmic Surgical Instruments Research Articles

Reusing Surgical Materials for Cataract Surgery: An Assessment of Potential Contamination.

To evaluate microbiological cultures of cataract surgical devices and products that were reused for multiple cases. Aravind Eye Hospital, Pondicherry, Tamil Nadu, India. Prospective cohort study. Samples from multiple surgical instruments and products that were reused for consecutive cataract surgeries underwent bacterial and fungal cultures and were monitored alongside positive controls for 7 days. This included instruments that were processed using immediate use steam sterilization (IUSS) between cases (e.g., surgical cannulas, syringes, phacoemulsification and coaxial/bimanual irrigation and aspiration (IA) tips, phacoemulsification and IA sleeves) (Group 1), instruments that were used without sterilization between cases (e.g., phacoemulsification tubing/handpieces, coaxial IA handpieces) (Group 2) and the residual (unused) fluid from balanced salt solution bags after being used for multiple patients (Group 3). 3,333 discrete samples were collected from all 3 product groups that were reused across multiple patients. In all collected samples, no bacterial or fungal growth was observed. Of the 3,241 cataract surgeries that utilized reused and IUSS-sterilized instruments alongside instrument sets cultured on the same day and balanced salt solution bags shared across multiple patients, no eyes developed endophthalmitis over a 6-week follow-up period. Bacterial or fungal growth was not found in extensive microbiological cultures of IUSS-sterilized ophthalmic surgical instruments, and cataract surgical products that were reused in multiple patients. This microbiological data complements clinical endophthalmitis data from 2 million consecutive cases at the Aravind Eye Hospital, suggesting that their instrument and surgical supply processing practices may allow for safe and sustainable ophthalmic care.

A Novel Electromagnetic Driving System for 5-DOF Manipulation in Intraocular Microsurgery.

This work presents a novel electromagnetic driving system that consists of eight optimized electromagnets arranged in an optimal configuration and employs a control framework based on an active disturbance rejection controller (ADRC) and virtual boundary. The optimal system configuration enhances the system's compatibility with other ophthalmic surgical instruments, while also improving its capacity to generate magnetic force in the vertical direction. Besides, the optimal electromagnet parameters provide a superior comprehensive performance on magnetic field generation capacity and thermal power. Hence, the presented design achieves a stronger capacity for sustained work. Furthermore, the ADRC controller effectively monitors and further compensates the total disturbance as well as gravity to enhance the system's robustness. Meanwhile, the implementation of virtual boundaries substantially enhances interactive security via collision avoidance. The magnetic and thermal performance tests have been performed on the electromagnet to verify the design optimization. The proposed electromagnet can generate a superior magnetic field of 2.071 mT at a distance of 65 mm with an applied current of 1 A. Moreover, it demonstrates minimal temperature elevation from room temperature (25 °C) to 46 °C through natural heat dissipation in 3 h, thereby effectively supporting prolonged magnetic manipulation of intraocular microsurgery. Furthermore, trajectory tracking experiments with disturbances have been performed in a liquid environment similar to the practical ophthalmic surgery scenarios, to verify the robustness and security of the presented control framework. The maximum root mean square (RMS) error of performance tests in different operation modes remains 35.8 μm, providing stable support for intraocular microsurgery.

Capsular tension ring explant complication rate comparison using Miyake-Apple video analysis.

To compare the complication rate and time required to explant standard capsular tension rings (CTRs) vs suture-guided CTRs (SGCTRs). Intermountain Ocular Research Center, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah. Experimental study. Eight cadaver eyes were prepared using standard Miyake-Apple protocol with digital video recording. A 4 clock-hour zonular dialysis was created, followed by a capsulorhexis, hydrodissection, and CTR (n = 4) or SGCTR (n = 4) implantation. With the CTR hidden from view by the overlying iris, ophthalmic surgical instruments were used to remove the CTRs. Time required to remove the CTR and any complications were recorded. A limit of 180 seconds was imposed to determine inability to remove the CTR. In the standard CTR group (n = 4), removal was associated with high rates of complication (100%). Complications included capsular tears (n = 2), dialysis extension (n = 1), and inadvertent intracapsular cataract extraction (n = 1). The SGCTR group had no complications associated with removal (n = 4). Time required to explant a CTR was significantly reduced from 164.5 seconds with standard CTRs to 6.9 seconds with SGCTRs (P = .001). Attempts to remove a standard CTR from the capsular bag was met with a high complication rate. The addition of suture to the leading eyelet of the CTR prior to implantation significantly reduced the time and effort required to remove the CTR and was associated with a significant reduction in complication rates.

Efficacy of Cleaning Methods for Ophthalmic Microscopic Instruments: A Comparison Study.

The combination of silicone oil and blood is difficult to remove from ophthalmic surgical instruments during cleaning and decontamination processes. We sought to establish the most efficient cleaning procedure for this type of contaminated instrument. We uniformly contaminated microscopic instruments made of titanium alloy and stainless steel with either blood alone or blood and silicone oil. We randomly assigned each instrument to one of four types of cleaning procedures that involved combinations of water, a multi-enzyme detergent, or an alkaline detergent. After completing the designated cleaning procedure, a sterile processing technician used an adenosine triphosphate cleaning verification test to evaluate the cleaning efficacy. When cleaning blood- and silicone oil-contaminated titanium-alloy and stainless-steel instruments, the alkaline detergent immersion followed by a multi-enzyme detergent ultrasonic cleaning yielded the highest cleaning effectiveness score (92.5%), which indicates this was the most effective of the four cleaning procedures that we tested.

Management of ophthalmic surgical instruments and processes optimization: mixed method study.

Analysis of the use of ophthalmic instruments during surgical procedures in order to propose a material management method. Mixed method study, sequential exploratory design, performed from January to June 2015, at a university hospital in southern Brazil. First, a qualitative approach was held from brainstorming and field observation. Themes were grouped into thematic categories. By connection, the quantitative stage happened through matrix arrangement and linear programming, culminating in the instrument management proposal. Given categories - instruments reorganization according to the time of the surgical procedure and the need surgical instruments for in each procedure - guided the definition of existing restrictions and application of mathematical models. There was an average reduction of 13.10% in the number of surgical instruments per tray and an increase of 17.88% in surgical production. This proposal allowed the rationalization and optimization of ophthalmic instruments, favoring sustainability of the organization.

Design Parameters for a Small-Gauge Fragmatome.

PurposeManufacturers of surgical instrumentation have increasingly sought to decrease the size of ophthalmic surgical instruments. We have used finite element modeling to model the stress and strain present in a fragmatome as a function of driving frequency and fragmatome dimensions.MethodsFinite element calculations using the COMSOL Multiphysics system v3.5 were used to elucidate the influence of wall thickness, length, and excitation frequency on a titanium fragmatome tube with outer diameters of 20, 23, 25, and 27 gauge.ResultsBy coupling structural mechanics, fluid mechanics, and acoustical physics, we were able to determine the eigenfrequencies (resonant frequencies) as well as parameters in which the von Mises stress in a fragmatome tube exceeds the yield strength, leading to destruction of the instrument.ConclusionSolid fragmatomes have far fewer possible failure modes than fragmatomes with a standard wall thickness. Eigenfrequency analysis and finite element calculations can be critical in predicting potentially catastrophic designs in modern surgical instruments.Translational RelevanceInstruments developed for microsurgical applications cannot always simply be scaled down versions of conventional instruments. Such an approach can lead to potentially dangerous intraoperative failures, such as a fragmatome shattering inside the eye. Modern engineering techniques are increasingly necessary to investigate potential instrument failure mechanisms and to optimize device performance in a design in silico before in vivo testing.

Analysis of the handling of ophthalmic surgical instruments in hospitals

Background: We investigated the procedures used by medical institutions in Guangdong Province for reprocessing ophthalmic surgical instruments and analyzed the problems identified in order to improve the quality of cleaning medical instruments and its management. Methods: The reprocessing of ophthalmic surgical instruments was investigated in 72 hospitals in Guangdong Province using a questionnaire designed for this purpose. Results: Ophthalmic surgical instruments underwent centralized reprocessing in the disinfection and supply centers in 50% of the 72 hospitals. Cataract phacoemulsification surgery was the main ophthalmic surgery performed in 94% of the 72 hospitals. The main reasons for using centralized reprocessing were an insufficient supply of ophthalmic surgical instruments, short turnaround times between surgeries, and the high cost of losing these precise and fragile instruments. Manual processing was the predominant method of reprocessing ophthalmic surgical instruments; enzyme detergents were used in 63.89% of the hospitals; and 48.61% of the hospitals used N-model small pressure-steam sterilizers for the ophthalmic surgical instruments. Conclusions: In order to improve the quality and management of the cleaning of medical instruments, and guarantee high-quality medical care, the following measures are recommended. Centralized management of ophthalmic surgical instruments should be based on the instruments’ characteristics. Pay more attention to reprocessing site locations and staff training. Choose detergents based on manufacturers’ instructions for use with specific instruments. Increase the number of available ophthalmic instruments in accordance with their demand and select appropriate small pressure-steam sterilizers.

Canadian ophthalmic microsurgery course: an innovative spin on wet lab–based surgical education

Wet lab and surgical simulation can reduce the learning curve of difficult surgical techniques, accelerate the rate for trainees to achieve surgical competency, and improve patient safety. To provide the most up-to-date information and hands-on experiences with novel ophthalmic surgical techniques and instruments, the Department of Ophthalmology at Western University has created a wet lab–based, multilevel microsurgery skills transfer course through collaboration with various industry partners. Several elements in the course goal and design differentiate this type of surgical course from typical wet labs: the format is multileveled surgical training, with a beginner level targeting undergraduate medical students, an intermediate level for ophthalmology residents, and an advanced level for trained ophthalmologist. In addition, the level of industry participation allows the development of true partnership and offers a method to introduce awareness and innovation in a cost-effective manner. This article presents the organization, course setup, and feedback from the pilot course.

The presence of stem cells in potential stem cell niches of the intervertebral disc region: an in vitro study on rats.

The potential of stem cell niches (SCNs) in the intervertebral disc (IVD) region, which may be of great significance in the regeneration process, was recently proposed. To the best of our knowledge, no previous in vitro study has examined the characteristics of stem cells derived from the potential SCN of IVD (ISN). Therefore, increasing knowledge on ISN-derived stem cells (ISN-SCs) may provide a greater understanding of IVD degeneration and regeneration processes. We aimed to demonstrate the existence of ISN-SCs and to compare their characteristics with bone marrow mesenchymal stem cells (BMSCs) in vitro. Sprague-Dawley rats (male, 10-week-old) were used in this study. ISN tissues were separated by ophthalmic surgical instruments under a dissecting microscope according to the anatomical areas. BMSCs and cells isolated from the ISN tissues were cultured and expanded in vitro. Passage 4 populations were used for further analysis with respect to colony-forming ability, cellular immunophenotype, cell cycle, stem cell-related gene expression, and proliferation and multipotential differentiation capacities. In general, both of ISN-SCs and mesenchymal stromal cells (MSCs) met the minimal criteria for the definition of multipotent mesenchymal stromal cells, including adherence to plastic, specific surface antigen expression, and multipotent differentiation potential. Especially, ISN-SCs even showed greater potential of osteogenesis and chondrogenesis. The ISN-SCs also expressed stem cell-related genes that were comparable to those of BMSCs, and had colony-forming and self-renewal abilities. To the best of our knowledge, this is the first in vitro study aimed towards determining the existence and characteristics of ISN-SCs, which belong to the MSC family and with greater osteogenic and chondrogenic abilities than BMSCs according to our data. This finding may be of great significance for additional studies that investigate the migration of ISN-SCs into the IVD, and may provide a new perspective on different biological approaches for IVD self-regeneration.

Surgical glove perforation among nurses in ophthalmic surgery: A case‐control study

Many of the ophthalmic surgical instruments are extremely fine and sharp. Due to the dim light environment required for ophthalmic surgical procedures, the passing of sharp instruments among surgeons and scrub nurses also poses a risk for glove perforations. A case-control study was performed to determine the number and site of perforations in the surgical gloves used by a group of scrub nurses during ophthalmic surgery. All six nurses working in an eye and refractive surgery centre in Hong Kong participated in the study. A total of 100 (50 pairs) used surgical gloves were collected following 50 ophthalmic surgeries. Fifty pairs of new surgical gloves were also collected. Every collected surgical glove underwent the water leak test. The surgical procedure perforation rate was 8%, and none of the perforations were detected by the scrub nurses. No perforations were found in any unused gloves. The findings indicate that glove perforations for scrub nurses during ophthalmic surgery do occur and mostly go unnoticed. Future studies should continue to explore factors contributing to surgical glove perforation.

An Investigation of Enzymatic Detergents as a Potential Cause of Toxic Anterior Segment Syndrome

To investigate whether enzymatic detergents used in cleaning ophthalmic surgical instruments can cause toxic anterior segment syndrome (TASS)-like responses in a rabbit model. Randomized, investigator-masked, controlled experimental animal study. Thirty-five New Zealand white rabbits. The rabbit eyes were randomized into 7 treatment groups to receive intracameral injection of 1 of 3 different doses of Medline Dual Detergent or Enzol Detergent, or sterile limulus amoebocyte lysate reagent water as a control. The eyes were evaluated for anterior segment inflammation at baseline and at 1, 3, 6, 24, 48, and 72 hours after treatment by slit-lamp biomicroscopy. Anterior chamber (AC) inflammation, including cells, flare, fibrin, and iris injection; time course of inflammation; and residual detergent levels in luminated instruments. Moderate to marked injection of the iris vessels was seen as early as 1 hour after treatment with the enzymatic detergents in 41 of 60 eyes, with the response being more severe in the Enzol Detergent-exposed eyes. Severe iris hemorrhages were accompanied by blood in the AC in 13 eyes, which usually persisted through 72 hours, with an associated increase in AC cell and flare. Corneal haze was present in 52 of 56 eyes 1 hour after treatment, but was mild and resolved within 24 hours in all but the Enzol 4.5%-exposed eyes. Median AC cell and flare peaked at 6 hours and resolved by 48 hours. Enzymatic detergents caused a severe but unusual response from the iris when injected intracamerally into rabbit eyes. This response has not been reported in humans with TASS. The time course of inflammation was faster (peak at 6 hours) and resolved more quickly (within 48 hours) than TASS. Simulated cleaning and extraction studies indicate that the level of residual detergent to which a patient could be exposed is significantly less than the lowest dose used in this study. Because that low dose caused no significant observations other than injection of the iris vessels, these results do not support residual enzymatic detergents on surgical instruments as a cause for TASS.

Risk of Creutzfeldt–Jakob disease transmission by ocular surgery and tissue transplantation

Creutzfeldt-Jakob disease (CJD) is a rare, fatal neurodegenerative disease that occurs in sporadic, genetic, variant, and iatrogenic forms. The transformation of normal prion protein (PrP(C)) to the abnormal form (PrP(Sc)) is a key step in the pathogenesis of CJD and leads to the accumulation of amyloid and spongiform changes in the brain. The presence of PrP(Sc) in tissue is a surrogate marker for CJD infectivity. Sporadic CJD, whose cause is unknown, is by far the most frequent form with 1-2 cases per million population occurring every year-the genetic forms of CJD are rather rarer. The majority of variant CJD cases have occurred in the United Kingdom, where there have been four reports of transmission of vCJD by blood transfusion. The great majority of iatrogenic transmissions of CJD have resulted from the use of pituitary-derived hormones or dura mater with only a very few cases attributable to neurosurgical instruments or corneal transplants. In the absence of a validated test for CJD infectivity in eye donors, the application of appropriate donor selection criteria and the use of single-use instruments in eye banks are currently the most effective means of reducing the risk of CJD transmission. Onward transmission by reusable ophthalmic surgical instruments has not been reported, but the risk cannot be excluded. Use of appropriate cleaning and disinfection protocols and the ability to identify and quarantine instruments that may have been used on an infected patient are important safeguards.

Ophthalmic Surgical Instruments

With proper training and diligent practice, many orbital, extraocular, and corneo-conjunctival surgeries can be successfully performed by the general practitioner. Specialized surgical instrumentation is necessary to achieve optimal results. This article reviews the essential surgical instruments required for these routine ophthalmic surgeries and provides guidelines for suture selection. Recommendations for handling and care of ophthalmic surgical instruments, including cleaning, sterilization, and storage, are provided.

Corneal and conjunctival toxicity of disinfectants—Assessing safety for use with ophthalmic surgical instruments

We investigated the corneal toxicity of ortho-phthalaldehyde (Cidex ROPA, Johnson and Johnson K.K.) and its predecessor glutaraldehyde (Cidex R, Johnson and Johnson K.K.). We made primary cultures of porcine and human corneal endothelial cells. Commercially available cell lines were also used including human, bovine, and rabbit corneal epithelium and human conjunctival cells. Following incubation for two days, cell survival was measured using a WST-1 assay for endothelia and a MTT assay for the other cells. Test solutions included 2.25% and 3.5% glutaraldehyde and 0.55% ortho-phthalaldehyde. Cell survival was presented as a percentage of the control value. ortho-phthalaldehyde displayed less toxicity than glutaraldehyde for all cell types tested. As expected 3.5% glutaraldehyde was slightly more toxic than 2.25% glutaraldehyde. When primary human corneal endothelial cultures were exposed to ortho-phthalaldehyde, the survival rates were 88% for 100-fold dilutions and 95% for 500-fold dilutions. The survival rates for all cells tested were greater than 90% when dilutions of 1000-fold or more were used. In conclusion, the corneal toxicity of glutaraldehyde and ortho-phthalaldehyde appears to be within safe levels following washing procedures and therefore the use of these disinfectants may be suitable for selected ophthalmic surgical instruments in urgent or under-equipped circumstances.

Tissue distribution of protease resistant prion protein in variant Creutzfeldt-Jakob disease using a highly sensitive immunoblotting assay

Variant Creutzfeldt-Jakob disease (vCJD) has a pathogenesis distinct from other forms of human prion disease: disease-related prion protein (PrP(Sc)) is readily detectable in lymphoreticular tissues. Quantitation of risk of secondary transmission, and targeting of risk reduction strategies, is limited by lack of knowledge about relative prion titres in these and other peripheral tissues, the unknown prevalence of preclinical vCJD, and a transmission barrier which limits the sensitivity of bioassay. We aimed to improve immunoblotting methods for high sensitivity detection of PrP(Sc) to investigate the distribution of PrP(Sc) in a range of vCJD tissues. We obtained tissues at necropsy from four patients with neuropathologically confirmed vCJD and from individuals without neurological disease. Tissues were analysed by sodium phosphotungstic acid precipitation of PrP(Sc) and western blotting using high sensitivity enhanced chemiluminescence. We could reliably detect PrP(Sc) in the equivalent of 50 nL 10% vCJD brain homogenate, with a maximum limit of detection equivalent to 5 nl. PrP(Sc) could be detected in tissue homogenates when present at concentrations 10(4)-10(5) fold lower than those reported in brain. Tonsil, spleen, and lymph node were uniformly positive for PrP(Sc) at concentrations in the range of 0.1-15% of those found in brain: the highest concentrations were consistently seen in tonsil. PrP(Sc) was readily detected in the retina and proximal optic nerve of vCJD eye at levels of 2.5 and 25%, respectively of those found in brain. Other peripheral tissues studied were negative for PrP(Sc) with the exception of low concentrations in rectum, adrenal gland, and thymus from a single patient with vCJD. vCJD appendix and blood (Buffy coat fraction) were negative for PrP(Sc) at this level of assay sensitivity. We have developed a highly sensitive immunoblot method for detection of PrP(Sc) in vCJD tissues that can be used to provide an upper limit on PrP(Sc) concentrations in peripheral tissues, including blood, to inform risk assessment models. Rectal and other gastrointestinal tissues should be further investigated to assess risk of iatrogenic transmission via biopsy instruments. Ophthalmic surgical instruments used in procedures involving optic nerve and the posterior segment of the eye, in particular the retina, might represent a potential risk for iatrogenic transmission of vCJD. Tonsil is the tissue of choice for diagnostic biopsy and for population screening of surgical tissues to assess prevalence of preclinical vCJD infection within the UK and other populations.

Demagnetizer for ophthalmic surgical instruments

Demagnetizer for ophthalmic surgical instruments

Microsurgery: A technical discussion for head and neck surgeons

AbstractDespite mechanical and technical advances that have been made in fields allied with microsurgery, Carrell and Guthrie's basic concept of small‐blood‐vessel anastomosis has not changed significantly. However, with refined, finer sutures and needles as well as improved jewelers' and ophthalmic surgical instruments, individuals can now readily practice under high magnification. With repeated practice using rats, the operator can successfully manage finer structures, such as blood vessels less than 1 mm in diameter. Head and neck surgeons have an advantage in this area because of their extensive experience and skill in manipulating operating microscopes.

The Care of Ophthalmic Surgical Instruments

The Care of Ophthalmic Surgical Instruments