MEMBRANE SCRAPER MADE BY POLYPROPYLENE LOOP
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-11-02 |
| Journal | Retina |
| Authors | Feng Jiang, Wenwen Zhang, YaâJun Liu, Feifei Chen, Zhenggao Xie |
| Institutions | Nanjing Drum Tower Hospital |
| Citations | 1 |
Abstract
Section titled âAbstractâComplete removal of vitreous cortex is important for surgical management of many vitreoretinal disorders, such as rhegmatogenous retinal detachment, proliferative diabetic retinopathy, and vitreomacular interface disorders. In most patients, posterior vitreous detachment (PVD) can be induced by active aspirating around optic disc with vitreous cutter or silicone-tipped needle.1,2 However, when the posterior hyaloid is firmly attached to the retina, or there is vitreoschisis in some cases, it may be difficult to fulfill detachment by active aspiration, and a membrane scraper is often required. After marking the vitreous cortex with triamcinolone acetonide, a break of vitreous cortex was made at the posterior pole with a scraper. Then vitreous detachment can be continued with vitreous cutter or silicone-tipped needle. At present, there are two kinds of membrane scraper commonly used in clinic: one is diamond dusted membrane scraper and the other is membrane flex loop. These tools, while effective, are costly and may not be available in some undeveloped areas. Therefore, we introduce a new method which can make a membrane scraper instantly during surgery. Our experience has proved that vitreous cortex can be detached effectively and safely from the retinal surface by this handmade membrane scraper. Membrane Scraper Made by a Polypropylene Loop The scraper was made of 5-0 polypropylene suture (Prolene, Polypropylene Suture, Ethicon, Johnson-Johnson, US) and a disposable 23 G needle. First, take a piece of 5-0 polypropylene suture about 15 to 20 cm in length. The 2 ends of the polypropylene suture were passed through the tip of the 23G needle and led out from the tail, forming a closed thread loop outside the tip. The ends of the thread were overlapped and tied using an overhand knot to make it easier to adjust the loop size. A keratome was used to make several partial thickness oblique cuts on one side of the thread loop. The cutting depth was about 1/5 of the suture diameter, with an interval of 0.3 mm to 0.5 mm, forming âbarbâ-shaped tines. Gently pull the thread outward from the end of the needle to shrink the loop until it matched with the tip of the needle, after which, a polypropylene scraper was created (Figure 1).Fig. 1.: Membrane scraper made by a polypropylene loop. A. Two ends of the polypropylene suture were passed through the tip of the 23 G needle and led out from the tail, forming a closed thread loop outside the tip. B. A keratome was used to make several partial thickness oblique cuts on one side of the thread loop. C. Gently pull the thread outward from the end of the needle to shrink the loop until it matched with the tip of the needle. D. Cutting depth is about 1/5 of the suture diameter, with an interval of 0.3 mm to 0.5 mm, forming âbarbâ-shaped tines.This handmade membrane scraper was operated in the same way as the commercially available diamond scraper or flex loop. Posterior vitreous detachment should be induced by the conventional method at first. Triamcinolone acetonide was injected into the vitreous cavity to visualize the transparent vitreous hyaloid, and then, the vitreous cutter was used to aspirate the posterior vitreous cortex around the optic disk. If this did not work, then we converted to our polypropylene scraper. Insert the scraper into the eye through the 23G trocar and be sure to keep the tip in the center of the vitreous cavity, away from the retina and lens. Hold the needle tip firmly in place and slightly introduce the thread into the eye with the help of endoilluminator probe in the other hand, until the loop was expanded to fit. At this point, the thread loop was similar as a droplet, approximately with a length of 4 mm and a width of 1.5 mm. Dock the syringe to the needle with the help of an assistant to fix the thread loop and also to serve as the handle of the scraper. The barbed side of the scraper was used to gently scrape against the surface of the retina. Once a break of the vitreous cortex was clearly present, the vitreous detachment can be continued by active aspiration of vitreous cutter (Figure 2). The scraperâs movement should be parallel to the retina to form a tangential traction. Be careful not to compress to the retina, so as to prevent iatrogenic retinal injury (see video, Supplemental Digital Content 1, https://links.lww.com/IAE/B534). Attention should be paid to the elasticity and rigidity of the polypropylene loop. If the elasticity or rigidity of the scraper was not appropriate, it can easily be adjusted by enlarging or shrinking the thread loop. It should be noticed that the loop needs to be shrunk before withdrawing the scraper, to prevent incarcerating in or even pulling out the trocar. To date, we have successfully induced PVD mechanically using this handmade membrane scraper in 15 surgeries without any complication.Fig. 2.: Posterior vitreous detachment was induced by the polypropylene scraper. The barbed side of the scraper was used to gently scrape against the surface of the retina. Notice the strong vitreous hooking effect in the figure. A. Vitreous scraping in rhegmatogenous retinal detachment. B. Vitreous scraping in proliferative diabetic retinopathy.Discussion Posterior vitreous detachment induction is the key step of vitrectomy and also the basic skill of vitreoretinal surgery. Remnants of posterior vitreous cortex after PVD may play roles in several macular and retinal disorders.3,4 In patients with rhegmatogenous retinal detachment, vitreous remnants can be associated with secondary macular hole, epimacular membrane, and proliferative vitreoretinopathy resulted in retinal redetachment. The residual cortex can also serve as a scaffold for cell proliferation, which can cause recurrence of fibrous vascular membrane and vitreous hemorrhage, and may finally lead to the failure of surgery in proliferative diabetic retinopathy. Therefore, the vitreous cortex should be completely removed during surgery. In most cases, PVD can be successfully induced by active aspiration. However, sometimes the adhesion of posterior hyaloid and internal limiting membrane may be too strong to separate. Several techniques have been attempted to solve this problem using various surgical instruments. Diamond dusted membrane scraper was used to create a break of the posterior vitreous cortex.5 Vander and Kleiner6 described a technique by using an intraocular coaxial bipolar diathermy to induce PVD. The posterior hyaloid was adhered to the diathermy tip and detachment was induced through lifting the tip. Microvitreoretinal blade can be used to dissect the vitreous cortex at the edge of the optic disc.7 van Overdam et al8 used a rectangular piece of polyvinyl alcohol held with intraocular forceps for removal of vitreous cortex remnants during vitrectomy. In addition, we also described the method of indocyanine green-assisted internal limiting membrane peeling to induce PVD in the cases with strong vitreoretinal adhesion.9 Among these methods, membrane scraper is more commonly used in clinical practice, with the simplest operation and the shortest learning curve. However, membrane scraper is disposable and expensive, and may not be available in clinical practice, which brings challenges to the complete vitreous removal. In this study, we designed a âloopâ-shaped scraper made by 5-0 polypropylene sutures which are very easy to get in clinical. The whole process only takes about 2 to 3 minutes. The cost is as low as one piece of polypropylene suture. Polypropylene sutures are commonly used in ophthalmology with stable physical and chemical properties and good histocompatibility. They have been widely used in eye surgery in recent years. During the making process, the 2 ends of the thread were inserted into a 23G needle to form a closed loop. A keratome was used to cut the thread obliquely to form microtines, which was oriented toward the needle. So that those tines will form a âbarbâ structure, which can easily âhook upâ the collagen fibers of the vitreous cortex. The size of the loop can be enlarged or shrunk to adjust the elasticity or rigidity of the scraper during vitreous scraping. We have successfully applied this handmade scraper to mechanically induce PVD and remove the vitreous remnants on the surface of the retina. We also found that the working efficiency of this handmade scraper was similar to the diamond dusted membrane scraper and the flex membrane loop, and no retinal bleeding, retinal tear, or other retinal injuries were observed during the operation. We currently use 5-0 polypropylene suture and 23G needle, which can be matched with 23G trocar surgery. However, whether it can be used in 25G or 27G surgery with a thin-wall needle or thinner polypropylene suture and whether it can be applied to internal limiting membrane peeling surgery needs further study. In summary, when commodity product is not available, a membrane scraper can be made with 5-0 polypropylene sutures instantly during the surgery. This new method is safe and efficient in PVD induction.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
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