Fig. 1.1
Retinal detachment secondary to high myopic macular hole (MHRD). (a) Fundus photograph shows a retinal detachment in the posterior pole which extends until the temporal quadrant, but a full-thickness MH cannot be easily recognized. (b) Preoperative OCT scan confirms the presence of a small macular hole with remnants of an attached posterior hyaloid superiorly to the fovea (white arrows). (c) Postoperatively, the retina is completely reattached as observed on color fundus photograph and (d) OCT scan confirms the MH closure and the flat retina above the macular indentation. (OCT scans obtained with Cirrus HD-OCT 4000 (Carl Zeiss Meditec, Dublic, CA); IMO (Instituto de Microcirugia Ocular), Barcelona, Spain)
2.
Macular hole with myopic foveoschisis (MH and MFS) [32, 33] (Fig. 1.2).
Fig. 1.2
Macular hole with myopic foveoschisis (MH and MFS). (a) Fundus photograph shows a shallow macular detachment, but a full-thickness MH cannot be easily recognized due to the lack of contrast which is caused by a severe chorioretinal atrophy in the macular area. (b) OCT scan confirms the presence of a full-thickness macular hole and a long-term retinoschisis in the temporal side corresponding to the atrophy showed on fundus photograph. Residual outer retinal layers under the retinoschisis (arrow heads) and a foveal detachment can also be observed. (c) On postoperative color fundus photograph, the scleral indentation obtained with the Ando plombe is clearly visible in the macular area where the schisis is totally resolved. (d) OCT scan confirms the MH closure and the flat retina above the macular indentation. Note the change of the concavity of the posterior staphyloma into a convex shape induced by the indenting buckle. (OCT scans obtained with Cirrus HD-OCT 4000 (Carl Zeiss Meditec, Dublic, CA); IMO (Instituto de Microcirugia Ocular), Barcelona, Spain)
3.
Myopic foveoschisis (MFS) with foveal detachment [28, 30, 32, 33]. In this last condition, the episcleral approach might be suggested in case of a thin “roof” in the area of foveal detachment to avoid the risk of inducing a full-thickness MH with PPV and ILM peeling (Fig. 1.3).
Fig. 1.3
Myopic foveoschisis (MFS) with foveal detachment. (a) Color fundus photograph of a high myopic patient showing an MH-like appearance. (b) Preoperative OCT reveals the presence of a myopic foveoschisis associated with foveal detachment. Note the hyperreflective line at the level of the inner retina (white arrow) which may be suggestive for an ILM detachment. An attached posterior hyaloid (arrow heads) is also observed on the same scan in the foveal area. (c) Postoperative fundus photograph shows a degree of RPE disturbance within the posterior pole, but the scleral indentation is not clearly visible. (d) However, SD-OCT confirms the reshaping of the posterior eye wall, the ILM peeling with inner retinal dimples (arrow heads), and a complete resolution of the foveoschisis. Moreover, the retina in the foveal area is totally reattached, but the loss of the IS ellipsoid band can also be observed at the level of the outer retina. (OCT scans obtained with Cirrus HD-OCT 4000 (Carl Zeiss Meditec, Dublic, CA); IMO (Instituto de Microcirugia Ocular), Barcelona, Spain)
1.2 Surgical Technique
1.2.1 Choice of Macular Buckle: Personal Experience
Different types of episcleral posterior buckles have been described in the literature [13–17, 24, 25, 28, 29]. However, our personal experience is mostly focused on three of them.
A silicone band (6 mm in width), usually used as an encircling buckle, was chosen as the first indenting device in all patients who underwent surgery prior to 2009.
The Ando plombe consists of a semitransparent T-shaped silicone rod embedded with titanium wires to give rigidity and permit them to be bent in order to achieve the desired curvature and optimal positioning of the squared (5 × 5 mm) indenting head under the fovea. The other end has ridges that facilitate its fixation with sutures to the temporal sclera. Two sizes may be selected, 25 or 27 mm, according to the axial length of the eye [22, 23] (Fig. 1.4).
Fig. 1.4
Graphic 3D representation of two types of macular buckles with additional light probe. (a) The Ando plombe consists of a semitransparent T-shaped silicone plate embedded with titanium wires. This design provides rigidity and allows the macular buckle to be bent in order to achieve the desired curvature and optimal positioning of the squared 5 × 5 mm indenting platform underneath the central macula. The proximal end has ridges that allow its fixation with sutures to the superotemporal scleral quadrant. An additional 29G optic fiber can be inserted through a 23G needle shaft. This needle will guide the light probe to the center of the indenting buckle head and will allow its optimal positioning under the macular due to transillumination. (b) The AJL macular buckle is made of silicone-coated polymethyl methacrylate (PMMA). It differs from the Ando plombe as it does not bend and has a rounded, 10 mm-diameter indenting platform. A groove in the indenting platform allows insertion of an optic fiber without using additional sutures or a needle shaft to localize more accurately the center of the platform during buckle positioning under the macula. (3D graphic design realized by Alex Couto; IMO (Instituto de Microcirugia Ocular), Barcelona, Spain)
The AJL macular buckle is made of silicone-coated polymethyl methacrylate (PMMA) and differs from the Ando plombe since it does not allow bending and has an 8 mm in diameter rounded indenting platform (Fig. 1.4).
In order to improve the positioning of the episceral device under the macular area, both the AJL macular buckle and Ando plombe may be supplied with an additional light probe as reported in a previous study [33] (Fig. 1.4).
However, according to the literature, since the surgical technique and the buckling effect of these posterior exoplants – Ando plombe (Ondeko Corporation, Tokyo, Japan) and AJL macular buckle (AJL Ophthalmic Spain) – are considered by the authors to be superior to the 6-mm silicone band, they were preferred from 2009 as episcleral indenting devices.
1.2.2 Exposure of the Appropriate Scleral Quadrant
Two different scleral approaches which do not require muscles disinsertion may be chosen depending on the type of the episceral buckle. These are for the 6-mm silicone band and Ando plombe or AJL macular buckle.
1.2.2.1 6-mm Silicone Band
A 360° temporal conjunctival peritomy is performed with separation of the Tenon capsule. The 6-mm silicone band is placed across the macular area from the inferonasal to the superonasal scleral quadrants, after isolating the superior, inferior, and temporal and nasal rectus muscles with a 3/0 silk suture (Fig. 1.5). Special attention has to be paid to be posterior to the complete inferior oblique insertion and to avoid damage to the inferotemporal vortex veins.
Fig. 1.5
(a) Using a 6-mm silicone band, a 360° peritomy is performed and the four rectus muscles are hooked with 3/0 silk sutures. (b) The inferior oblique tendon is then hooked. Special care must be taken to hook it completely and to avoid separation of its fibers. If this happens, the correct position of the band will be blocked, and it will go through the muscle fibers. (c) The inferior end is then sutured to the sclera with a 5/0 nylon suture near the insertion of the inferior rectus muscle in the nasal quadrant, pointing toward the macular area. (e) The superior end is left free in the superotemporal quadrant during the intraocular maneuvers. (d, f) Once vitreous surgery has been completed, the superior end needs to be pulled until the buckling effect is achieved and the silicone band can then be sutured to the superonasal sclera with a 5/0 nylon suture
The inferior end is then sutured to the sclera with a 5/0 nylon suture near the insertion of the inferior rectus muscle in the nasal quadrant. The superior end is left free in the superotemporal quadrant during vitrectomy. Once vitreous surgery has been completed and the buckling effect over the macula is achieved, the superior end of the silicone band can be finally sutured to the superonasal sclera with a 5/0 nylon suture (Fig. 1.5).
1.2.2.2 Ando Plombe or AJL Macular Buckle
The superotemporal quadrant is further preferred for an easier and better placement of the buckle and with the aim of avoiding the inferior oblique muscle which runs posteriorly and laterally along the entire inferotemporal quadrant.
A 140° superotemporal conjunctival peritomy is performed with separation of the Tenon capsule. The superior and temporal rectus muscles are isolated and hooked using a 3/0 silk suture to allow a better exposure of the scleral quadrant (Fig. 1.6).
Fig. 1.6
(a) A 140° superotemporal conjunctival peritomy is performed with separation of the Tenon capsule. (b) Lateral and (c) superior rectus muscles are isolated and hooked using a 3/0 silk suture to allow a better exposure of the superotemporal scleral quadrant
When the temporal sclera is exposed, a 5/0 nylon suture is placed in the superotemporal quadrant between the insertion of both superior and inferior oblique muscles, about 20 mm from the corneal limbus. Particular care must be taken during this step in order to avoid damage to the vortex veins located near the superior oblique’s tendon (Fig. 1.7).
Fig. 1.7
(a) After exposing the temporal sclera, a 5/0 nylon suture is placed in the superotemporal quadrant at a position between the insertion of both the superior and inferior oblique muscles, about 20 mm from the corneal limbus (b)
It is recognized that high myopia may lead to a progressive scleral thinning which may increase the risk of perforation of the eye, forcing the surgeon in some cases to look for a better location to place the initial mattress suture (Fig. 1.8). For the same reason, trying to reduce the risk of unintentional hypotony and choroidal effusion in case of scleral perforation, we preferred to apply this first nylon suture in a closed eye.
Fig. 1.8
(a) The first 5/0 nylon suture must be carefully placed to avoid perforation of the eye wall due to a thinner sclera. (b) The arrow shows the site of unintentional perforation during the suture’s placement. (c, d) illustrates a patient with a previous encircling buckling who underwent second surgery for persistent retinal detachment secondary to a macular hole. The Ando plombe macular buckle is placed in the superotemporal quadrant under the encircling band. Both scleral indentations are visible in the postoperative wide-field fundus photograph. (Ultrawide-field color fundus photographs obtained with Optomap 200MA (Optos PLC, Dunfermline, Fife, Scotland); IMO (Instituto de Microcirugia Ocular), Barcelona, Spain)
In the case of patients that have an encircling band due to a previous rhegmatogenous retinal detachment, the surgeon can place the macular buckle under the encircling silicone band and avoid its removal whenever it is possible (Fig 1.8).
1.2.3 Pars Plana Vitrectomy
Although the choice of using a 20G, 23G, 25G, or 27G system is mostly based on the surgeon’s personal preference, it is crucial that any instrument chosen must be long enough to allow the operator to reach the posterior pole of the eye. This procedure can be difficult in these special cases of great axial length. If a sufficiently long instrument is used, any less invasive technique of a standard three-port PPV can be used.
Since high myopic patients tend to be younger and the posterior hyaloid tends to be degenerated and more often not completely detached, triamcinolone acetonide (TA) may be used to facilitate the posterior vitreous detachment (PVD). Depending on the surgeon’s experience, the posterior hyaloid can be removed using vitreous cutter, forceps, and/or the Tano diamond-dusted scraper (Fig 1.9). In this last case, remnants of collagen’s fibers can be gently peeled off from the inner retinal surface.
Fig. 1.9
Triamcinolone acetonide (TA) can be used to facilitate posterior vitreous detachment (PVD). The posterior hyaloid and/or remnants of vitreous cortex can be removed using (a) vitreous cutter, (b) forceps, and/or (c) a Tano diamond-dusted scraper
In case of retreatment, even after silicone oil removal, if present, PPV should be extended until the vitreous base and completed with the help of a bimanual technique and scleral indentation (Fig 1.10). Indeed, it is well known that an accurate vitreous cortex removal is a crucial factor in order to prevent surgical failure and reduce the risk of PVR [20]. Pars plana lensectomy (PPL) with sparing of the anterior capsule can be also carried out before PPV allowing a better and complete shaving of the vitreous base. Furthermore, lens removal may improve the ILM visualization during the ILM peeling procedure.
Fig. 1.10
It is recommended to perform complete pars plana vitrectomy (PPV) by accurately removing the vitreous cortex as well as removing the vitreous base. It can be completed with a bimanual technique and scleral indentation. This procedure will avoid the development of proliferative vitreoretinopathy (PVR) which is one of the significant risk factors of surgical failure
1.2.4 Dyes
Epiretinal membrane (ERM) and the ILM can be peeled off using green or blue dyes such as ICG, trypan blue, brilliant blue, or both.
To prevent the spilling or leakage of the dye from passing into the subretinal space, a small bubble of perfluorocarbon (PFC) can be injected to temporarily cover the hole in case of MHRD. As an alternative procedure, dyes can be mixed with viscoelastic making them heavier and reducing the risk of dye accumulation under the retina (Fig 1.11). This can make the fluid-air exchange or temporary closure of the infusion unnecessary.
Fig. 1.11
(a) If there is macular hole retinal detachment (MHRD), in order to avoid the dye passing into the subretinal space, (b) blue dye can be mixed with viscoelastic. This makes the dye heavier and more viscous and reduces the risk of the dye spilling under the retina. (c) After the mixture of trypan blue and viscoelastic substance is removed, a stain of preretinal structures is clearly observed
1.2.5 Use of PFC
It is widely recognized that high myopic eyes have a thin sclera. In spite of continuous irrigation, trying to maintain the intraocular pressure (IOP) may be difficult especially when sclerotomies are performed with a 20G system and also in case of not-valved 23G or smaller trocars. This can occur when instruments are temporarily pulled out through the sclerotomies during any surgical maneuvers, with a rapid and severe decrease of the IOP. We have to be careful with these sudden changes of the IOP, because not every PPV device has an internal pressure control which avoids rapid IOP changes. In light of all these considerations, since hypotony has been considered one of the main risks of intraoperative choroidal effusion (especially in cases of a thin sclera as occurs in high myopic eyes), a PFC temporary tamponade may be preferred during the ERM/ILM peeling to prevent any additional risk. Thus, when most of the dye has been aspirated, PFC can be slowly injected and ERM/ILM may subsequently be removed.
In case of MHRD, another interesting advantage of using PFC is that it also displaces any subretinal fluid to the periphery. When the detachment is extended until the peripheral retinal and there is no a peripheral break, a small retinotomy can be performed superiorly to the horizontal meridian to drain the fluid (Fig 1.12). This also avoids the need to aspirate it through the MH reducing the risk of enlargement and trauma to the borders of the hole.
