Vitrectomy Machines, Fluidics, and Small-Gauge Systems Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
25-Gauge Vitrectomy Marco Mura a · Francesco Barca b
a Academic
Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Chirurgia Oftalmica, Azienda Ospedaliero Universitaria Pisana (AOUP), Pisa, Italy
Abstract The development of a 25-gauge vitrectomy system represents a major step forward in vitreoretinal surgery. The main advantages of small-gauge incisions are reduction of surgical time, decreased postoperative inflammation, and fast postoperative recovery time. The use of this technique requires research, training, knowledge, and experience on the part of the vitreoretinal surgeon and the personnel in the operation room. At the same time the indications for 25-gauge vitrectomy have changed a lot in the last years due to improvement in materials and technology and the advent of new instruments. Nowadays, with the development of new surgical instrumentation and the improvement of surgical skills, we can approach the whole spectrum of vitreoretinal pathology. This chapter describes the instruments used in 25-gauge vitrectomy, explains how to set the vitrectomy machine for safe surgery and what the indications for 25-gauge vitrectomy are (with particular reference to vitreoretinal interface diseases, retinal detachment, and proliferative diabetic retinopathy) as well as the complications that can occur, and provides some pearls for challenging cases. © 2014 S. Karger AG, Basel
The development of the 25-gauge vitrectomy system was an important step in vitreoretinal surgery. Introduced and developed by de Juan and
colleagues in 2002 [1, 2], it is now widely used in the treatment of several vitreoretinal diseases. This technique, called ‘transconjunctival sutureless vitrectomy’, can achieve real sutureless surgery due to its small caliber. The main advantages of small-gauge incisions are shortening of surgical time, reduction of postoperative inflammation, and fast postoperative recovery time. The use of this technique requires research, training, knowledge, and experience on the part of the vitreoretinal surgeon and the personnel in the operation room. At the same time, the surgical tools have to be constantly updated. Indications
The indications for 25-gauge vitrectomy have changed a great deal in the last years due to improvement in materials and technology and the advent of new instruments. Initially the 25-gauge vitrectomy system was used to treat less complicated elective vitreoretinal pathology such as macular holes and macular pucker, moderate vitreous bleedings, and uncomplicated primary retinal detachments [3]. Nowadays, with the development of new surgical instrumentation and the improvement of the individual surgical skills, we
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
b U.O.
Instrumentation
The system consists of a specific set of microcannulas and a series of instruments specifically designed for this gauge. Standard microcannulas have a shaft 3.5 mm in length (usually polyamide or steel) with an internal and external diameter of 0.4 and 0.5 mm, respectively. On the extraocular portion, they have a little collar that can be grabbed to manipulate the cannula itself. Once introduced through the scleral wall they maintain their position without the need for suturing. In cases with a thickened eye wall (e.g. choroidal detachment), longer microcannulas (5 mm) are available to avoid suprachoroidal infusion. Multiple surgical instruments have been designed for the 25-gauge system: vitrectomy probe, light fibers, laser probes (straight, curved, directional), microforceps [internal limiting membrane (ILM) forceps, serrated jaws, end-grasping, asymmetrical, etc.], scissors (horizontal or vertical cutting), bipolar cautery, illuminated pick, diamond-dusted scraper, etc. In combination with these instruments, several types of 25-gauge light probes for wide-angle endoillumination are currently available. These are called chandelier-style illuminators that produce homogenous and wide-
46
Fig. 1. 25-gauge trocar insertion. The conjunctiva is displaced superiorly with an anatomic forceps while the trocar cannula is inserted at about a 30° angle through the conjunctiva and sclera.
angle endoillumination, making them perfect for use in combination with a panoramic-viewing system. Wound Construction and Cannula Removal
Sclerotomy construction is fundamental in sutureless surgery because a good result is dependent on the water tightness of the sclerotomy (fig. 1). Before inserting the trocar cannula, the conjunctiva should be displaced (with blunt forceps or cotton tip) in such a way to obtain a misalignment of the sclerotomy and the conjuctival wound when the cannula is removed. The authors perform sclerotomies 3.5 mm from the limbus in pseudophakic and aphakic eyes and 4 mm in phakic patients. We introduce the microvitreoretinal blade with a 30° angle until the edge of the shaft of the microcannula is reached; the microblade is then verticalized and introduced in the vitreous cavity perpendicular to the scleral plane. This technique creates a biplanar self-sealing scleral incision at the end of the operation. The trocar cannulas are essential in modern 25-gauge vitrec-
Mura · Barca Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
can approach the whole spectrum of the vitreoretinal pathology [4]. Many surgeons, including the authors, make use of this technology not only to treat common disease of the vitreoretinal interface, but also for more complex cases like vitreous hemorrhages, retinal detachments complicated with proliferative vitreoretinopathy (PVR) or giant retinal tear, proliferative diabetic retinopathy with or without tractional retinal detachment, and ocular trauma. The 25-gauge system can be used to perform challenging surgical procedures like macular translocation or retinal pigment epithelium (RPE)-choroid transplantation, which previously was only possible with 20-gauge instrumentation.
tomy because they allow the alignment between displaced conjunctiva and sclera, making possible an atraumatic insertion and removal of the different types of instruments in and out the eye protecting the vitreous base from possible iatrogenic damage. The trocar cannulas can be with or without valves. In the authors’ experience, a valved system offers major stability for the vitreous cavity, which avoids leakage of vitreous and fluid. This reduces the risk of vitreoretinal incarceration in the scleral wound and helps to keep intraocular pressure stable during surgery. The cannulas have to be removed tangentially to facilitate the apposition of the internal and external aspects of the sclerotomy with the pressure exerted by the intraocular pressure. In case of sclerotomy leakage, it is usually sufficient to massage the sclerotomy itself in a gentle and accurate way to allow the closure of the wound. In those cases where a tamponade agent (gas or silicone oil) is not required, the authors perform a complete fluid-air exchange. In fact, the higher superficial tension of the air bubble compared to the irrigation fluid allows a better closure of the scleral wound.
vitreoretinal surgeons performed 25-gauge vitrectomy with a 3D modality to partially compensate for the reduced aspiration flow rate at the highest cut rate and the increased traction at high vacuum levels. The new generation of vitrectomy systems have cutters and aspiration pumps which are able to ensure an optimal flow rate at a very high cut rate, minimizing vitreoretinal traction. The highspeed vitrectomy probe is able to cut the vitreous in very small fragments, which reduces the viscosity of the vitreous and the resistance inside the probe lumen and tubing, which substantially increases the flow rate and reduces indirectly the traction from the vitreous on the retina. The machine is set with an initial aspiration of 0 mm Hg and moves linearly to 650 mm Hg when the foot pedal is fully depressed, maintaining a fixed cut rate of 5,000, 6,000, or 7,500 cuts/min depending on the platform used. In this way, we have a maximum aspiration flow and cut rate during core vitrectomy, and, vice versa, a minimum aspiration flow during vitreous shaving when lower traction on the vitreoretinal surface is required. Vitrectomy
All the vitrectomy machines that are currently available can simultaneously cut and aspirate the vitreous, which generates pulsatile traction on the retinal surface. An ideal vitrectomy machine would not exert such traction. Today, with the new small-gauge instruments and high cut rate (high-speed vitrectomy), it is possible to reduce the amount of pulsatile traction generated during a vitrectomy procedure. Thanks to this technology, the new vitrectomy platforms are able to drastically reduce the traction applied to the retina because the vitreous can be fragmented in very small pieces before been aspirated by the vitrectomy probe. This has also made it possible to return to a proportional aspiration system (proportional vacuum). Until a few years ago, the majority of the
25-gauge vitrectomy consists of three main steps: core vitrectomy, posterior hyaloid separation (if uncompleted), and peripheral vitrectomy (‘vitreous shaving’). Core vitrectomy is the first step, and has the goal of making an opening in the anterior vitreous cortex and creating a cavity in the central vitreous. In this phase it is possible to use the maximum vacuum (650 mm Hg) with the highest cut rate (5,000, 6,000, or 7,500 cuts/min). Once the central vitreous is removed, the second step is the induction or the completion of posterior vitreous detachment. Posterior vitreous detachment is induced approximating the port of the vitreous probe (with the cutter off) to the optic disc and increasing progressively the aspiration until reaching the maximum level (range: 500–650 mm Hg). The maneuver needs to be re-
25-Gauge Vitrectomy Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
47
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
High-Speed Vitrectomy and Machine Set
Macular Surgery
In macular surgery, removal of all macular epiretinal membranes is essential for a good surgical outcome. For the removal of these membranes we have several types of 25-gauge forceps, for example the Tano or Eckardt ILM forceps and endgrasping or asymmetrical forceps. We usually start the peeling from the center of the membrane (inside-out peeling technique [5]), which can be identified by the orientation of the retinal folds, or we start from the thicker part of the epiretinal membrane, usually recognizable as the most opaque area. Once the membrane is pinched and
48
Fig. 2. 25-gauge cannula location during retinal detachment surgery with the chandelier in the inferonasal quadrant.
peeling is started, it is essential to proceed tangentially to the retinal plane and with circular movements around the foveal area to avoid inadvertent retinal touches. It is also very important to observe the fovea throughout the entire procedure to avoid iatrogenic foveal decapitation or breaks. ILM peeling is also achievable with the same technique, and adjuvant staining solutions even make it easier by providing better visualization of the ILM itself as well as enhancing the cleavage plane between the retina and ILM. Retinal Detachment
The small caliber of the 25-gauge probe and the high cut rate are of extreme importance in the treatment of a retinal detachment because they have the advantage of reducing the number of intraoperative retinal breaks, thus minimizing vitreous turbulence and reducing dynamic vitreoretinal traction. This is a very important aspect
Mura · Barca Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
peated several times until the posterior hyaloid becomes visibly engaged in the vitrectomy port, after which the separation from the optic disc is completed along the whole disc circumference. At this stage, the hyaloid is slowly pulled anteriorly towards the lens, keeping a constant aspiration of about 300–400 mm Hg. We suggest performing this maneuver only until reaching the midperiphery to avoid retina traction at the level of the vitreous base with consequent iatrogenic retinal breaks. During this procedure it is mandatory to pay attention to the presence of abnormal vitreoretinal adhesion, such as in cases of diabetic patients who have undergone panretinal photocoagulation or in cases or lattice degeneration areas. In these cases, the adherence between vitreous and retina is stronger than normal and the risk of an iatrogenic break is very high. We believe that the induction of posterior vitreous detachment is the most important surgical moment. Leaving the hyaloid in place could in fact work as a scaffold for cell proliferation, creating tangential traction that could result in macular puckers and/or PVR. Vitreous shaving is the last step of the vitrectomy. If accessory illumination is present, the shaving can be performed by the surgeon himself; otherwise, the assistant will be the one performing the scleral depression (fig. 2).
Fig. 3. 25-gauge vitreous base dissection using the bimanual technique with scleral depression and chandelier light system.
treat breaks when a single small break (≤1 o’clock) is present as well as with multiple (2–3 max.) and superior breaks. Endolaser is performed for larger (>1 o’clock) and/or inferior breaks, multiple breaks (>3), and for giant retinal breaks, retinectomies, and PVR cases. Giant Break
The surgical treatment of the giant retinal breaks [8], both associated or not associated with retinal detachment, is a challenge even for experienced retinal surgeons. The biggest improvement in the treatment of this disease has probably been the introduction of PFCL, which has improved the prognosis of this disease. We perform a complete vitrectomy with vitreous base shaving. The edge of the giant tear is then unrolled with the help of gentle suction (vitrectomy probe or soft-tipped extrusion needle) when PVR is not present or with the bimanual technique with the use of an illuminated spatula or chandelier light and a serrated jaws-type forceps when PVR has already developed. With a soft-tipped cannula, the disin-
25-Gauge Vitrectomy Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
49
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
considering that a recently detached retina is usually very mobile. For this reason, having technology that can reduce the vitreous traction on a mobile retina makes the procedure much safer. We use the 25-gauge vitrectomy system [4, 6] in all types of retinal detachment, and in those complicated by PVR [7], giant retinal tears, choroidal detachment, etc. To ensure a good surgical outcome, posterior vitreous detachment induction (when not present) represents for us the key to the surgical procedure because the traction exerted by the hyaloid left in place is the primary cause of development of new retinal breaks and PVR. Another key point is the removal of the traction at the level of the anterior edge of the retinal breaks; sometimes the amputation of the anterior flap of the retinal break is necessary to be sure all vitreoretinal tractions have been removed. We do not believe it is necessary to perform a complete vitrectomy (vitreous shaving with deep sclera depression) in every case. In fact, we routinely perform vitreous base shaving in cases with posterior attachment of the vitreous base, in myopic cases with peripheral retinal degeneration, in diabetics and sickle cell cases with fibrovascular proliferation, and in cases with PVR grade C and higher (fig. 3). We always make sure that the subretinal fluid is thoroughly aspirated to facilitate retina RPE adhesion and avoid the formation of undesirable retinal folds at the macular level. The fluid is removed from the preexisting retinal break when this is accessible; otherwise, a new retinotomy is performed peripherally (nasal better than temporal, and superior better than inferior quadrant). Perfluorocarbon liquid (PFCL) helps make the procedure simpler. Another technique we use is to first drain the subretinal fluid during fluidair exchange as routinely done; if subretinal fluid is still present in macular area, it can be pushed away towards the primary break using PFCL under air. PFCL is then removed making sure to aspirate the little amount of water from the PFCLair interface. The breaks are then treated with endolaser or cryotherapy. We use cryotherapy to
Management of Proliferative Vitreoretinopathy
PVR is an excessive healing reaction of the retina to damage (e.g. retinal detachment, trauma). We routinely perform 25-gauge vitrectomy in every retinal detachment with PVR. In planning the surgery, it is extremely important to localize the PVR (anterior and/or posterior; epiretinal and/or subretinal) and its extension (number of quadrants involved). PFCL is very useful because it has a very low viscosity (2–3 cSt) and is easily injected through small-caliber cannulas (e.g. 25 gauge). In fact, PFCL has modified the surgical approach to PVR. The traditional approach before its introduction was first the management of the anterior PVR and then the posterior PVR. The use of PFCL has reversed this strategy, leading to management from the posterior pole to the ora serrata [9]. Nowadays, we first address the posterior PVR; once it is completely removed we stabilize the posterior retina with PFCL and can address the anterior PVR safely. If the retina is not flattened with a PFCL bubble, it means that there is residual epiretinal traction that needs further peeling, sometimes associated with retinectomy. In case of epiretinal proliferation, we stain the membranes with a mixture of trypan blue and brilliant peel to better identify the tissue and make
50
sure with a second staining the tissue has been removed. Subretinal proliferation needs to be addressed in a different way. It is not always necessary to remove cases in which the membranes are flat and very localized. In such cases, it is possible to test the elasticity of the retina by performing fluid-air exchange and drainage of the subretinal fluid; if the retina goes flat, it means that the elasticity is well preserved and the focal membrane does not need to be removed. If the retina does not flatten, removal of the subretinal membrane is then necessary. Subretinal dendritic PVR needs to be removed and can be done with end-grasping or serrated jaws forceps via a small retinotomy. When the PVR is very extensive, it is usually necessary to perform a retinectomy and access the subretinal space by flipping the retina outside-in. Also in this case, serrated jaws and/or end-grasping forceps are the preferred choice in our center. Proliferative Diabetic Retinopathy
The improvement of medical care, new laser technology, and advent of the intravitreal injection of different sorts of drugs has reduced the need for a surgical approach to diabetic retinopathy. Vitrectomy, however, plays a crucial role in the management and treatment of the complications of diabetic retinopathy [10]. Surgical indications for 25-gauge vitrectomy are tractional retinal detachment threatening or involving the macula, neovascular glaucoma, anterior vitreous cortex fibrovascular proliferation, and vitreous or preretinal hemorrhage. The first surgical step when approaching an eye with proliferative diabetic retinopathy is to evaluate the condition of the posterior vitreous cortex (PVC) and its relation with the retinal surface; in fact, the PVC can be totally or partially detached from the retina or completely adherent. The cases in which the PVC is totally detached from the retinal surface are generally the less complex to treat. In these cases there is no trac-
Mura · Barca Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
serted edge of the retina is then lifted and PFCL is injected towards the optic disc until the edge of the giant break is adherent to the underlying RPE. Endolaser photocoagulation is now applied to the posterior edge of the tear making sure to seal it up to the ora serrata on both sides. The choice of the tamponade agent depends on the retinal conditions and the location of the giant break. A superior giant retinal break without PVR can be tamponaded with a long-acting gas such as perfluoropropane (C3F8 12%). Silicone oil is still the best option for giant retinal breaks with PVR that are not superiorly located.
Fig. 4. Bimanual cutter delamination in proliferative diabetic retinopathy. Chandelier light provides illumination while the surgeon lifts the fibrovascular tissue with end-grasping forceps and cuts the tissue with the cutter.
the delamination of the fibrovascular pegs. In cases of focal and/or weak adhesion, delamination is possible using simple end-grasping forceps (fig. 4). However, if the adhesion is broad and/or strong, it is better to use a bimanual technique that requires the use of an additional chandelier light, endgrasping forceps, and the vitrectomy probe or curved scissors. Delamination is then performed lifting the fibrovascular pegs with the forceps and cutting with the blade of the scissors or the port of the vitrectomy probe at the root of the fibrovascular peg, removing the tissue completely. The advantage of 25-gauge vitrectomy is evident; in fact, the small caliber of the probe and the position of the port located on the distal end of the shaft makes it possible to insert it in narrow spaces such as between the retina and the fibrovascular tissue. Challenging and Other Cases
The old concept that 25-gauge vitrectomy is not suitable for the most challenging cases was revised many years ago. Excessive flexibility, reduced caliber and poor efficiency of the pumps, and being unable to reach usable aspiration flow with reduced gauge were the reasons many surgeons gave for not using this system for difficult cases. Tech-
25-Gauge Vitrectomy Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
51
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
tion on the retina, and once the vitreous and the PVC have been removed, the surgery can be completed with panretinal endolaser photocoagulation if necessary. When the PVC is adherent, the complexity of the surgery varies proportionally to the degree of adherence of the cortex to the retina. In such cases, there are several possible techniques. We do not use the segmentation technique anymore, but we still employ delamination because we think that leaving residual fibrovascular tissue on the retinal surface may result in chronically elevated retinal areas that may also lead to rhegmatogenous retinal detachment in case of atrophic hole formation, or to a recurrent vitreous hemorrhage. However, the segmentation technique can be helpful as a first step of delamination when very broad and long fibrovascular adhesion is present; segmenting these broad areas before delaminating them can reduce traction on adjacent retinal tissue, with consequent reduction of iatrogenic breaks. Vitreoretinal proliferation usually arises at the level of the optic disc and the major retinal vessels. As a first step, we advise removing or circumscribing the PVC and to isolate every fibrovascular attachment point to avoid anteroposterior traction and iatrogenic retinal tears during delamination. This step is achieved using the highest cut rate and the lowest vacuum possible. Afterwards, we proceed to
nology has evolved and today we have vitrectomy machines able to reach high vacuum levels and a high cut rate without compromising aspiration flow. According to Poiseuille’s law, the resistance to flow in a capillary tube is inversely proportional to the fourth power of the radius, i.e. to overcome this limit and reach acceptable flows, it was necessary develop vitrectomy machines able to reach high vacuum levels as well as very high cut rates to cut the vitreous fibers in pieces small enough to be aspirated without blocking the lumen of the vitrectomy probe. Evolution in the materials has also made possible the production of stiffer probes comparable to a bigger gauge possible. In our clinical practice, we perform 25-gauge vitrectomy in every case: ocular trauma (open or closed), intraocular foreign body removal, removal of dense subretinal blood, macular translocation, and RPE-choroid transplantation [11–13]. Complications
Minimally invasive surgery has become more popular since it became available on a large scale in 2004. A 2012 survey presented at the American Society of Retina Specialists showed that in 2005 only 20% of the surgeons were using small-gauge surgery as a first technique, while 90% of surgeons were using it in 2012. We feel this data can be explained by the fact that complications during a vitreoretinal procedure are not related to the gauge used. Some years ago Kunimoto and Kaiser [14] and Scott et al. [15] reported a higher incidence of endophthalmitis using small-gauge sutureless instruments. Other
studies have shown that the higher risk was only due to wrong construction of the sclerotomy ports. Changing from a straight to oblique incision reduced the incidence of endophthalmitis and postoperative hypotony to values comparable to the 20-gauge sutured technique [16]. A high cut rate [17, 18], small gauges, and the use of trocar cannulas have also reduced the incidence of iatrogenic retinal breaks and consequent retinal detachment. Conclusions
A new technique must be shown to be safe and efficient at least as much as the standard technique before it can be introduced to the market. 25-gauge vitrectomy was immediately shown to be safe and efficient, ensuring a faster and painless postoperative recovery for the patient. Initially considered as a possibility for less complex surgical cases (e.g. macular surgery), this technology, due to continuous research and the improvement in materials, is now used to treat every type of pathology in vitreoretinal surgery. The majority of the complications are independent from the gauge used. Surgery without risks is a utopian dream. Endophthalmitis, iatrogenic retinal breaks, and retinal detachment are just some examples of complications possible with any technique used. In our experience, and supported by clinical studies, having a technique that generates less vitreoretinal traction [19] represents undoubtedly a great advantage in terms of safety and efficacy [17].
References
52
2 de Juan E Jr, Hickingbotham D: Refinements in microinstrumentation for vitreous surgery. Am J Ophthalmol 1990; 109:218–220.
3 Ibarra MS, Hermel M, Prenner JL, Hassan TS: Longer-term outcomes of transconjunctival sutureless 25-gauge vitrectomy. Am J Ophthalmol 2005;139: 831–836.
Mura · Barca Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
1 Fujii GY, de Juan E Jr, Humayun MS, Pieramici DJ, Chang TS, Awh C, Ng E, Barnes A, Wu SL, Sommerville DN: A new 25-gauge instrument system for transconjunctival sutureless vitrectomy surgery. Ophthalmology 2002;109: 1807–1812.
10 Farouk MM, Naito T, Sayed KM, Nagasawa T, Katome T, Radwan G, Abdallah A, Elagouz M: Outcomes of 25-gauge vitrectomy for proliferative diabetic retinopathy. Graefes Arch Clin Exp Ophthalmol 2011;249:369–376. 11 Kunikata H, Uematsu M, Nakazawa T, Fuse N: Successful removal of large intraocular foreign body by 25-gauge microincision vitrectomy surgery. J Ophthalmol 2011;2011:940323. 12 Kunikata H, Fuse N, Abe T: Fixating dislocated intraocular lens by 25-gauge vitrectomy. Ophthalmic Surg Lasers Imaging 2011;42:297–301. 13 Ho LY, Walsh MK, Hassan TS: 25-gauge pars plana vitrectomy for retained lens fragments. Retina 2010;30:843–849. 14 Kunimoto DY, Kaiser RS: Incidence of endophthalmitis after 20- and 25-gauge vitrectomy. Ophthalmology 2007;114: 2133–2137. 15 Scott IU, Flynn HW Jr, Dev S, Shaikh S, Mittra RA, Arevalo JF, Kychenthal A, Acar N: Endophthalmitis after 25-gauge and 20-gauge pars plana vitrectomy: incidence and outcomes. Retina 2008; 28:138–142.
16 Oshima Y, Kadonosono K, Yamaji H, Inoue M, Yoshida M, Kimura H, Ohji M, Shiraga F, Hamasaki T, Japan Microincision Vitrectomy Surgery Study Group: Multicenter survey with a systematic overview of acute-onset endophthalmitis after transconjunctival microincision vitrectomy surgery. Am J Ophthalmol 2010;150:716–725. 17 Rizzo S, Genovesi-Ebert F, Belting C: Comparative study between a standard 25-gauge vitrectomy system and a new ultrahigh-speed 25-gauge system with duty-cycle control in the management treatment of various vitreoretinal pathologies. Retina 2011;31:2007–2013. 18 Rizzo S, Belting C, Genovesi-Ebert F, di Bartolo E: Incidence of retinal detachment after small-incision, sutureless pars plana vitrectomy compared with conventional 20-gauge vitrectomy in macular hole and epiretinal membrane surgery. Retina 2010;30:1065–1071. 19 Teixeira A, Chong LP, Matsuoka N, Arana L, Kerns R, Bhadri P, Humayun M: Vitreoretinal traction created by conventional cutters during vitrectomy. Ophthalmology 2010;117:1387–1392.
Marco Mura Academic Medical Center, University of Amsterdam Meibergdreef 9 NL–1105AZ Amsterdam (The Netherlands) E-Mail [email protected]
25-Gauge Vitrectomy Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
53
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
4 Mura M, Tan SH, de Smet MD: Use of 25-gauge vitrectomy in the management of primary rhegmatogenous retinal detachment. Retina 2009;29:1299–1304. 5 Charles S, Calzada J, Wood B: Vitreous Microsurgery, ed 5. Philadelphia, Wolters Kluwer/Lippincott Williams & Wilkins, 2011, p 62. 6 Dell’Omo R, Barca F, Tan HS, Bijl HM, Oberstein SY, Mura M: Pars plana vitrectomy for the repair of primary, inferior rhegmatogenous retinal detachment associated to inferior breaks. A comparison of a 25-gauge versus a 20-gauge system. Graefes Arch Clin Exp Ophthalmol 2013;251:485–490. 7 Iwahashi-Shima C, Sato T, Bando H, Ikeda T, Emi K: Anatomic and functional outcomes of 25-gauge vitrectomy for repair of eyes with rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy. Clin Ophthalmol 2013;7:2043–2049. 8 Kunikata H, Abe T, Nishida K: Successful outcomes of 25- and 23-gauge vitrectomies for giant retinal tear detachments. Ophthalmic Surg Lasers Imaging 2011;42:487–492. 9 Ryan JS: Perfluorocarbon liquids in vitreoretinal surgery; in: Retina, ed 4. Amsterdam, Elsevier Mosby, 2005, vol 3, p 2179.
25-Gauge Vitrectomy Marco Mura a · Francesco Barca b
a Academic
Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Chirurgia Oftalmica, Azienda Ospedaliero Universitaria Pisana (AOUP), Pisa, Italy
Abstract The development of a 25-gauge vitrectomy system represents a major step forward in vitreoretinal surgery. The main advantages of small-gauge incisions are reduction of surgical time, decreased postoperative inflammation, and fast postoperative recovery time. The use of this technique requires research, training, knowledge, and experience on the part of the vitreoretinal surgeon and the personnel in the operation room. At the same time the indications for 25-gauge vitrectomy have changed a lot in the last years due to improvement in materials and technology and the advent of new instruments. Nowadays, with the development of new surgical instrumentation and the improvement of surgical skills, we can approach the whole spectrum of vitreoretinal pathology. This chapter describes the instruments used in 25-gauge vitrectomy, explains how to set the vitrectomy machine for safe surgery and what the indications for 25-gauge vitrectomy are (with particular reference to vitreoretinal interface diseases, retinal detachment, and proliferative diabetic retinopathy) as well as the complications that can occur, and provides some pearls for challenging cases. © 2014 S. Karger AG, Basel
The development of the 25-gauge vitrectomy system was an important step in vitreoretinal surgery. Introduced and developed by de Juan and
colleagues in 2002 [1, 2], it is now widely used in the treatment of several vitreoretinal diseases. This technique, called ‘transconjunctival sutureless vitrectomy’, can achieve real sutureless surgery due to its small caliber. The main advantages of small-gauge incisions are shortening of surgical time, reduction of postoperative inflammation, and fast postoperative recovery time. The use of this technique requires research, training, knowledge, and experience on the part of the vitreoretinal surgeon and the personnel in the operation room. At the same time, the surgical tools have to be constantly updated. Indications
The indications for 25-gauge vitrectomy have changed a great deal in the last years due to improvement in materials and technology and the advent of new instruments. Initially the 25-gauge vitrectomy system was used to treat less complicated elective vitreoretinal pathology such as macular holes and macular pucker, moderate vitreous bleedings, and uncomplicated primary retinal detachments [3]. Nowadays, with the development of new surgical instrumentation and the improvement of the individual surgical skills, we
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
b U.O.
Instrumentation
The system consists of a specific set of microcannulas and a series of instruments specifically designed for this gauge. Standard microcannulas have a shaft 3.5 mm in length (usually polyamide or steel) with an internal and external diameter of 0.4 and 0.5 mm, respectively. On the extraocular portion, they have a little collar that can be grabbed to manipulate the cannula itself. Once introduced through the scleral wall they maintain their position without the need for suturing. In cases with a thickened eye wall (e.g. choroidal detachment), longer microcannulas (5 mm) are available to avoid suprachoroidal infusion. Multiple surgical instruments have been designed for the 25-gauge system: vitrectomy probe, light fibers, laser probes (straight, curved, directional), microforceps [internal limiting membrane (ILM) forceps, serrated jaws, end-grasping, asymmetrical, etc.], scissors (horizontal or vertical cutting), bipolar cautery, illuminated pick, diamond-dusted scraper, etc. In combination with these instruments, several types of 25-gauge light probes for wide-angle endoillumination are currently available. These are called chandelier-style illuminators that produce homogenous and wide-
46
Fig. 1. 25-gauge trocar insertion. The conjunctiva is displaced superiorly with an anatomic forceps while the trocar cannula is inserted at about a 30° angle through the conjunctiva and sclera.
angle endoillumination, making them perfect for use in combination with a panoramic-viewing system. Wound Construction and Cannula Removal
Sclerotomy construction is fundamental in sutureless surgery because a good result is dependent on the water tightness of the sclerotomy (fig. 1). Before inserting the trocar cannula, the conjunctiva should be displaced (with blunt forceps or cotton tip) in such a way to obtain a misalignment of the sclerotomy and the conjuctival wound when the cannula is removed. The authors perform sclerotomies 3.5 mm from the limbus in pseudophakic and aphakic eyes and 4 mm in phakic patients. We introduce the microvitreoretinal blade with a 30° angle until the edge of the shaft of the microcannula is reached; the microblade is then verticalized and introduced in the vitreous cavity perpendicular to the scleral plane. This technique creates a biplanar self-sealing scleral incision at the end of the operation. The trocar cannulas are essential in modern 25-gauge vitrec-
Mura · Barca Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
can approach the whole spectrum of the vitreoretinal pathology [4]. Many surgeons, including the authors, make use of this technology not only to treat common disease of the vitreoretinal interface, but also for more complex cases like vitreous hemorrhages, retinal detachments complicated with proliferative vitreoretinopathy (PVR) or giant retinal tear, proliferative diabetic retinopathy with or without tractional retinal detachment, and ocular trauma. The 25-gauge system can be used to perform challenging surgical procedures like macular translocation or retinal pigment epithelium (RPE)-choroid transplantation, which previously was only possible with 20-gauge instrumentation.
tomy because they allow the alignment between displaced conjunctiva and sclera, making possible an atraumatic insertion and removal of the different types of instruments in and out the eye protecting the vitreous base from possible iatrogenic damage. The trocar cannulas can be with or without valves. In the authors’ experience, a valved system offers major stability for the vitreous cavity, which avoids leakage of vitreous and fluid. This reduces the risk of vitreoretinal incarceration in the scleral wound and helps to keep intraocular pressure stable during surgery. The cannulas have to be removed tangentially to facilitate the apposition of the internal and external aspects of the sclerotomy with the pressure exerted by the intraocular pressure. In case of sclerotomy leakage, it is usually sufficient to massage the sclerotomy itself in a gentle and accurate way to allow the closure of the wound. In those cases where a tamponade agent (gas or silicone oil) is not required, the authors perform a complete fluid-air exchange. In fact, the higher superficial tension of the air bubble compared to the irrigation fluid allows a better closure of the scleral wound.
vitreoretinal surgeons performed 25-gauge vitrectomy with a 3D modality to partially compensate for the reduced aspiration flow rate at the highest cut rate and the increased traction at high vacuum levels. The new generation of vitrectomy systems have cutters and aspiration pumps which are able to ensure an optimal flow rate at a very high cut rate, minimizing vitreoretinal traction. The highspeed vitrectomy probe is able to cut the vitreous in very small fragments, which reduces the viscosity of the vitreous and the resistance inside the probe lumen and tubing, which substantially increases the flow rate and reduces indirectly the traction from the vitreous on the retina. The machine is set with an initial aspiration of 0 mm Hg and moves linearly to 650 mm Hg when the foot pedal is fully depressed, maintaining a fixed cut rate of 5,000, 6,000, or 7,500 cuts/min depending on the platform used. In this way, we have a maximum aspiration flow and cut rate during core vitrectomy, and, vice versa, a minimum aspiration flow during vitreous shaving when lower traction on the vitreoretinal surface is required. Vitrectomy
All the vitrectomy machines that are currently available can simultaneously cut and aspirate the vitreous, which generates pulsatile traction on the retinal surface. An ideal vitrectomy machine would not exert such traction. Today, with the new small-gauge instruments and high cut rate (high-speed vitrectomy), it is possible to reduce the amount of pulsatile traction generated during a vitrectomy procedure. Thanks to this technology, the new vitrectomy platforms are able to drastically reduce the traction applied to the retina because the vitreous can be fragmented in very small pieces before been aspirated by the vitrectomy probe. This has also made it possible to return to a proportional aspiration system (proportional vacuum). Until a few years ago, the majority of the
25-gauge vitrectomy consists of three main steps: core vitrectomy, posterior hyaloid separation (if uncompleted), and peripheral vitrectomy (‘vitreous shaving’). Core vitrectomy is the first step, and has the goal of making an opening in the anterior vitreous cortex and creating a cavity in the central vitreous. In this phase it is possible to use the maximum vacuum (650 mm Hg) with the highest cut rate (5,000, 6,000, or 7,500 cuts/min). Once the central vitreous is removed, the second step is the induction or the completion of posterior vitreous detachment. Posterior vitreous detachment is induced approximating the port of the vitreous probe (with the cutter off) to the optic disc and increasing progressively the aspiration until reaching the maximum level (range: 500–650 mm Hg). The maneuver needs to be re-
25-Gauge Vitrectomy Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
47
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
High-Speed Vitrectomy and Machine Set
Macular Surgery
In macular surgery, removal of all macular epiretinal membranes is essential for a good surgical outcome. For the removal of these membranes we have several types of 25-gauge forceps, for example the Tano or Eckardt ILM forceps and endgrasping or asymmetrical forceps. We usually start the peeling from the center of the membrane (inside-out peeling technique [5]), which can be identified by the orientation of the retinal folds, or we start from the thicker part of the epiretinal membrane, usually recognizable as the most opaque area. Once the membrane is pinched and
48
Fig. 2. 25-gauge cannula location during retinal detachment surgery with the chandelier in the inferonasal quadrant.
peeling is started, it is essential to proceed tangentially to the retinal plane and with circular movements around the foveal area to avoid inadvertent retinal touches. It is also very important to observe the fovea throughout the entire procedure to avoid iatrogenic foveal decapitation or breaks. ILM peeling is also achievable with the same technique, and adjuvant staining solutions even make it easier by providing better visualization of the ILM itself as well as enhancing the cleavage plane between the retina and ILM. Retinal Detachment
The small caliber of the 25-gauge probe and the high cut rate are of extreme importance in the treatment of a retinal detachment because they have the advantage of reducing the number of intraoperative retinal breaks, thus minimizing vitreous turbulence and reducing dynamic vitreoretinal traction. This is a very important aspect
Mura · Barca Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
peated several times until the posterior hyaloid becomes visibly engaged in the vitrectomy port, after which the separation from the optic disc is completed along the whole disc circumference. At this stage, the hyaloid is slowly pulled anteriorly towards the lens, keeping a constant aspiration of about 300–400 mm Hg. We suggest performing this maneuver only until reaching the midperiphery to avoid retina traction at the level of the vitreous base with consequent iatrogenic retinal breaks. During this procedure it is mandatory to pay attention to the presence of abnormal vitreoretinal adhesion, such as in cases of diabetic patients who have undergone panretinal photocoagulation or in cases or lattice degeneration areas. In these cases, the adherence between vitreous and retina is stronger than normal and the risk of an iatrogenic break is very high. We believe that the induction of posterior vitreous detachment is the most important surgical moment. Leaving the hyaloid in place could in fact work as a scaffold for cell proliferation, creating tangential traction that could result in macular puckers and/or PVR. Vitreous shaving is the last step of the vitrectomy. If accessory illumination is present, the shaving can be performed by the surgeon himself; otherwise, the assistant will be the one performing the scleral depression (fig. 2).
Fig. 3. 25-gauge vitreous base dissection using the bimanual technique with scleral depression and chandelier light system.
treat breaks when a single small break (≤1 o’clock) is present as well as with multiple (2–3 max.) and superior breaks. Endolaser is performed for larger (>1 o’clock) and/or inferior breaks, multiple breaks (>3), and for giant retinal breaks, retinectomies, and PVR cases. Giant Break
The surgical treatment of the giant retinal breaks [8], both associated or not associated with retinal detachment, is a challenge even for experienced retinal surgeons. The biggest improvement in the treatment of this disease has probably been the introduction of PFCL, which has improved the prognosis of this disease. We perform a complete vitrectomy with vitreous base shaving. The edge of the giant tear is then unrolled with the help of gentle suction (vitrectomy probe or soft-tipped extrusion needle) when PVR is not present or with the bimanual technique with the use of an illuminated spatula or chandelier light and a serrated jaws-type forceps when PVR has already developed. With a soft-tipped cannula, the disin-
25-Gauge Vitrectomy Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
49
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
considering that a recently detached retina is usually very mobile. For this reason, having technology that can reduce the vitreous traction on a mobile retina makes the procedure much safer. We use the 25-gauge vitrectomy system [4, 6] in all types of retinal detachment, and in those complicated by PVR [7], giant retinal tears, choroidal detachment, etc. To ensure a good surgical outcome, posterior vitreous detachment induction (when not present) represents for us the key to the surgical procedure because the traction exerted by the hyaloid left in place is the primary cause of development of new retinal breaks and PVR. Another key point is the removal of the traction at the level of the anterior edge of the retinal breaks; sometimes the amputation of the anterior flap of the retinal break is necessary to be sure all vitreoretinal tractions have been removed. We do not believe it is necessary to perform a complete vitrectomy (vitreous shaving with deep sclera depression) in every case. In fact, we routinely perform vitreous base shaving in cases with posterior attachment of the vitreous base, in myopic cases with peripheral retinal degeneration, in diabetics and sickle cell cases with fibrovascular proliferation, and in cases with PVR grade C and higher (fig. 3). We always make sure that the subretinal fluid is thoroughly aspirated to facilitate retina RPE adhesion and avoid the formation of undesirable retinal folds at the macular level. The fluid is removed from the preexisting retinal break when this is accessible; otherwise, a new retinotomy is performed peripherally (nasal better than temporal, and superior better than inferior quadrant). Perfluorocarbon liquid (PFCL) helps make the procedure simpler. Another technique we use is to first drain the subretinal fluid during fluidair exchange as routinely done; if subretinal fluid is still present in macular area, it can be pushed away towards the primary break using PFCL under air. PFCL is then removed making sure to aspirate the little amount of water from the PFCLair interface. The breaks are then treated with endolaser or cryotherapy. We use cryotherapy to
Management of Proliferative Vitreoretinopathy
PVR is an excessive healing reaction of the retina to damage (e.g. retinal detachment, trauma). We routinely perform 25-gauge vitrectomy in every retinal detachment with PVR. In planning the surgery, it is extremely important to localize the PVR (anterior and/or posterior; epiretinal and/or subretinal) and its extension (number of quadrants involved). PFCL is very useful because it has a very low viscosity (2–3 cSt) and is easily injected through small-caliber cannulas (e.g. 25 gauge). In fact, PFCL has modified the surgical approach to PVR. The traditional approach before its introduction was first the management of the anterior PVR and then the posterior PVR. The use of PFCL has reversed this strategy, leading to management from the posterior pole to the ora serrata [9]. Nowadays, we first address the posterior PVR; once it is completely removed we stabilize the posterior retina with PFCL and can address the anterior PVR safely. If the retina is not flattened with a PFCL bubble, it means that there is residual epiretinal traction that needs further peeling, sometimes associated with retinectomy. In case of epiretinal proliferation, we stain the membranes with a mixture of trypan blue and brilliant peel to better identify the tissue and make
50
sure with a second staining the tissue has been removed. Subretinal proliferation needs to be addressed in a different way. It is not always necessary to remove cases in which the membranes are flat and very localized. In such cases, it is possible to test the elasticity of the retina by performing fluid-air exchange and drainage of the subretinal fluid; if the retina goes flat, it means that the elasticity is well preserved and the focal membrane does not need to be removed. If the retina does not flatten, removal of the subretinal membrane is then necessary. Subretinal dendritic PVR needs to be removed and can be done with end-grasping or serrated jaws forceps via a small retinotomy. When the PVR is very extensive, it is usually necessary to perform a retinectomy and access the subretinal space by flipping the retina outside-in. Also in this case, serrated jaws and/or end-grasping forceps are the preferred choice in our center. Proliferative Diabetic Retinopathy
The improvement of medical care, new laser technology, and advent of the intravitreal injection of different sorts of drugs has reduced the need for a surgical approach to diabetic retinopathy. Vitrectomy, however, plays a crucial role in the management and treatment of the complications of diabetic retinopathy [10]. Surgical indications for 25-gauge vitrectomy are tractional retinal detachment threatening or involving the macula, neovascular glaucoma, anterior vitreous cortex fibrovascular proliferation, and vitreous or preretinal hemorrhage. The first surgical step when approaching an eye with proliferative diabetic retinopathy is to evaluate the condition of the posterior vitreous cortex (PVC) and its relation with the retinal surface; in fact, the PVC can be totally or partially detached from the retina or completely adherent. The cases in which the PVC is totally detached from the retinal surface are generally the less complex to treat. In these cases there is no trac-
Mura · Barca Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
serted edge of the retina is then lifted and PFCL is injected towards the optic disc until the edge of the giant break is adherent to the underlying RPE. Endolaser photocoagulation is now applied to the posterior edge of the tear making sure to seal it up to the ora serrata on both sides. The choice of the tamponade agent depends on the retinal conditions and the location of the giant break. A superior giant retinal break without PVR can be tamponaded with a long-acting gas such as perfluoropropane (C3F8 12%). Silicone oil is still the best option for giant retinal breaks with PVR that are not superiorly located.
Fig. 4. Bimanual cutter delamination in proliferative diabetic retinopathy. Chandelier light provides illumination while the surgeon lifts the fibrovascular tissue with end-grasping forceps and cuts the tissue with the cutter.
the delamination of the fibrovascular pegs. In cases of focal and/or weak adhesion, delamination is possible using simple end-grasping forceps (fig. 4). However, if the adhesion is broad and/or strong, it is better to use a bimanual technique that requires the use of an additional chandelier light, endgrasping forceps, and the vitrectomy probe or curved scissors. Delamination is then performed lifting the fibrovascular pegs with the forceps and cutting with the blade of the scissors or the port of the vitrectomy probe at the root of the fibrovascular peg, removing the tissue completely. The advantage of 25-gauge vitrectomy is evident; in fact, the small caliber of the probe and the position of the port located on the distal end of the shaft makes it possible to insert it in narrow spaces such as between the retina and the fibrovascular tissue. Challenging and Other Cases
The old concept that 25-gauge vitrectomy is not suitable for the most challenging cases was revised many years ago. Excessive flexibility, reduced caliber and poor efficiency of the pumps, and being unable to reach usable aspiration flow with reduced gauge were the reasons many surgeons gave for not using this system for difficult cases. Tech-
25-Gauge Vitrectomy Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
51
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
tion on the retina, and once the vitreous and the PVC have been removed, the surgery can be completed with panretinal endolaser photocoagulation if necessary. When the PVC is adherent, the complexity of the surgery varies proportionally to the degree of adherence of the cortex to the retina. In such cases, there are several possible techniques. We do not use the segmentation technique anymore, but we still employ delamination because we think that leaving residual fibrovascular tissue on the retinal surface may result in chronically elevated retinal areas that may also lead to rhegmatogenous retinal detachment in case of atrophic hole formation, or to a recurrent vitreous hemorrhage. However, the segmentation technique can be helpful as a first step of delamination when very broad and long fibrovascular adhesion is present; segmenting these broad areas before delaminating them can reduce traction on adjacent retinal tissue, with consequent reduction of iatrogenic breaks. Vitreoretinal proliferation usually arises at the level of the optic disc and the major retinal vessels. As a first step, we advise removing or circumscribing the PVC and to isolate every fibrovascular attachment point to avoid anteroposterior traction and iatrogenic retinal tears during delamination. This step is achieved using the highest cut rate and the lowest vacuum possible. Afterwards, we proceed to
nology has evolved and today we have vitrectomy machines able to reach high vacuum levels and a high cut rate without compromising aspiration flow. According to Poiseuille’s law, the resistance to flow in a capillary tube is inversely proportional to the fourth power of the radius, i.e. to overcome this limit and reach acceptable flows, it was necessary develop vitrectomy machines able to reach high vacuum levels as well as very high cut rates to cut the vitreous fibers in pieces small enough to be aspirated without blocking the lumen of the vitrectomy probe. Evolution in the materials has also made possible the production of stiffer probes comparable to a bigger gauge possible. In our clinical practice, we perform 25-gauge vitrectomy in every case: ocular trauma (open or closed), intraocular foreign body removal, removal of dense subretinal blood, macular translocation, and RPE-choroid transplantation [11–13]. Complications
Minimally invasive surgery has become more popular since it became available on a large scale in 2004. A 2012 survey presented at the American Society of Retina Specialists showed that in 2005 only 20% of the surgeons were using small-gauge surgery as a first technique, while 90% of surgeons were using it in 2012. We feel this data can be explained by the fact that complications during a vitreoretinal procedure are not related to the gauge used. Some years ago Kunimoto and Kaiser [14] and Scott et al. [15] reported a higher incidence of endophthalmitis using small-gauge sutureless instruments. Other
studies have shown that the higher risk was only due to wrong construction of the sclerotomy ports. Changing from a straight to oblique incision reduced the incidence of endophthalmitis and postoperative hypotony to values comparable to the 20-gauge sutured technique [16]. A high cut rate [17, 18], small gauges, and the use of trocar cannulas have also reduced the incidence of iatrogenic retinal breaks and consequent retinal detachment. Conclusions
A new technique must be shown to be safe and efficient at least as much as the standard technique before it can be introduced to the market. 25-gauge vitrectomy was immediately shown to be safe and efficient, ensuring a faster and painless postoperative recovery for the patient. Initially considered as a possibility for less complex surgical cases (e.g. macular surgery), this technology, due to continuous research and the improvement in materials, is now used to treat every type of pathology in vitreoretinal surgery. The majority of the complications are independent from the gauge used. Surgery without risks is a utopian dream. Endophthalmitis, iatrogenic retinal breaks, and retinal detachment are just some examples of complications possible with any technique used. In our experience, and supported by clinical studies, having a technique that generates less vitreoretinal traction [19] represents undoubtedly a great advantage in terms of safety and efficacy [17].
References
52
2 de Juan E Jr, Hickingbotham D: Refinements in microinstrumentation for vitreous surgery. Am J Ophthalmol 1990; 109:218–220.
3 Ibarra MS, Hermel M, Prenner JL, Hassan TS: Longer-term outcomes of transconjunctival sutureless 25-gauge vitrectomy. Am J Ophthalmol 2005;139: 831–836.
Mura · Barca Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
1 Fujii GY, de Juan E Jr, Humayun MS, Pieramici DJ, Chang TS, Awh C, Ng E, Barnes A, Wu SL, Sommerville DN: A new 25-gauge instrument system for transconjunctival sutureless vitrectomy surgery. Ophthalmology 2002;109: 1807–1812.
10 Farouk MM, Naito T, Sayed KM, Nagasawa T, Katome T, Radwan G, Abdallah A, Elagouz M: Outcomes of 25-gauge vitrectomy for proliferative diabetic retinopathy. Graefes Arch Clin Exp Ophthalmol 2011;249:369–376. 11 Kunikata H, Uematsu M, Nakazawa T, Fuse N: Successful removal of large intraocular foreign body by 25-gauge microincision vitrectomy surgery. J Ophthalmol 2011;2011:940323. 12 Kunikata H, Fuse N, Abe T: Fixating dislocated intraocular lens by 25-gauge vitrectomy. Ophthalmic Surg Lasers Imaging 2011;42:297–301. 13 Ho LY, Walsh MK, Hassan TS: 25-gauge pars plana vitrectomy for retained lens fragments. Retina 2010;30:843–849. 14 Kunimoto DY, Kaiser RS: Incidence of endophthalmitis after 20- and 25-gauge vitrectomy. Ophthalmology 2007;114: 2133–2137. 15 Scott IU, Flynn HW Jr, Dev S, Shaikh S, Mittra RA, Arevalo JF, Kychenthal A, Acar N: Endophthalmitis after 25-gauge and 20-gauge pars plana vitrectomy: incidence and outcomes. Retina 2008; 28:138–142.
16 Oshima Y, Kadonosono K, Yamaji H, Inoue M, Yoshida M, Kimura H, Ohji M, Shiraga F, Hamasaki T, Japan Microincision Vitrectomy Surgery Study Group: Multicenter survey with a systematic overview of acute-onset endophthalmitis after transconjunctival microincision vitrectomy surgery. Am J Ophthalmol 2010;150:716–725. 17 Rizzo S, Genovesi-Ebert F, Belting C: Comparative study between a standard 25-gauge vitrectomy system and a new ultrahigh-speed 25-gauge system with duty-cycle control in the management treatment of various vitreoretinal pathologies. Retina 2011;31:2007–2013. 18 Rizzo S, Belting C, Genovesi-Ebert F, di Bartolo E: Incidence of retinal detachment after small-incision, sutureless pars plana vitrectomy compared with conventional 20-gauge vitrectomy in macular hole and epiretinal membrane surgery. Retina 2010;30:1065–1071. 19 Teixeira A, Chong LP, Matsuoka N, Arana L, Kerns R, Bhadri P, Humayun M: Vitreoretinal traction created by conventional cutters during vitrectomy. Ophthalmology 2010;117:1387–1392.
Marco Mura Academic Medical Center, University of Amsterdam Meibergdreef 9 NL–1105AZ Amsterdam (The Netherlands) E-Mail [email protected]
25-Gauge Vitrectomy Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 45–53 (DOI: 10.1159/000360448)
53
Downloaded by: Nanyang Technological Univ. 198.143.39.67 - 6/12/2015 10:20:32 AM
4 Mura M, Tan SH, de Smet MD: Use of 25-gauge vitrectomy in the management of primary rhegmatogenous retinal detachment. Retina 2009;29:1299–1304. 5 Charles S, Calzada J, Wood B: Vitreous Microsurgery, ed 5. Philadelphia, Wolters Kluwer/Lippincott Williams & Wilkins, 2011, p 62. 6 Dell’Omo R, Barca F, Tan HS, Bijl HM, Oberstein SY, Mura M: Pars plana vitrectomy for the repair of primary, inferior rhegmatogenous retinal detachment associated to inferior breaks. A comparison of a 25-gauge versus a 20-gauge system. Graefes Arch Clin Exp Ophthalmol 2013;251:485–490. 7 Iwahashi-Shima C, Sato T, Bando H, Ikeda T, Emi K: Anatomic and functional outcomes of 25-gauge vitrectomy for repair of eyes with rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy. Clin Ophthalmol 2013;7:2043–2049. 8 Kunikata H, Abe T, Nishida K: Successful outcomes of 25- and 23-gauge vitrectomies for giant retinal tear detachments. Ophthalmic Surg Lasers Imaging 2011;42:487–492. 9 Ryan JS: Perfluorocarbon liquids in vitreoretinal surgery; in: Retina, ed 4. Amsterdam, Elsevier Mosby, 2005, vol 3, p 2179.
