Management of Specific Diseases Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
Idiopathic Macular Hole Hideyasu Oh
Abstract Idiopathic macular hole is a disease that arises from adhesion in the vitreomacular interface and can theoretically be treated by vitrectomy surgery. Surgical techniques include removal of the vitreous with or without simultaneous peeling of the internal limiting membrane (ILM), fluid-air exchange, and gas tamponade. Since the advent of microincision vitrectomy surgery, macular hole surgery has been performed with minimal invasiveness, and significant visual improvement is a common outcome. This chapter describes the pathology of this disease, including presurgical evaluation using optical coherence tomography (OCT), and then shows the fundamental techniques required for the surgery. Also important is the understanding of the postsurgical ‘healing’ process of the disease, which may confirm the fact that the subjective improvement is closely related to the retinal imaging obtained by OCT. More recent advances are the inverted ILM peeling technique for larger macular holes and 27-gauge vitrectomy that can potentially minimize the surgical invasiveness mainly by smaller wound construction and the reduced volume of irrigation during surgery. © 2014 S. Karger AG, Basel
Macular holes had long been regarded as an incurable disease until Kelly and Wendel [1, 2] reported that vitrectomy in combination with in-
traocular gas tamponade can be the first modality to treat this disorder with a remarkable success rate. Gass [3, 4] first reported the potential pathogenesis of idiopathic macular holes based on biomicroscopic findings. He proposed that the vitreous cortex remaining on the macula after spontaneous posterior vitreous separation will contract and lead to tear formation at the macula in an eccentric fashion. After the advent of optical coherence tomography (OCT), investigators were able to show the presence of localized vitreomacular adhesion at the central fovea in stage 1 and stage 2 macular holes [5, 6]. The adhesion is surrounded by a shallow posterior hyaloid separation [called perifoveal posterior vitreous detachment (PVD)] [5, 7], and its existence has convinced observers that anteroposterior traction also plays a crucial role in pathogenesis [8]. Based on these key findings, researchers adopted a OCT-based classification of macular holes, which is highly compatible in clinical settings (fig. 1): stage 1a = retinal split, foveal cyst or foveal detachment with a vitreous cortex attachment to the fovea; stage 1b = dehiscence of photoreceptor layer with a vitreous cortex attachment to the fovea; stage 2 = full-thickness hole covered by a flap-like tissue extending from
Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/17/2015 3:27:22 PM
Hyogo Prefectural Amagasaki Hospital, Amagasaki, Hyogo, Japan
a
b
c
d
Fig. 1. Spectral domain OCT image of macular holes: stage 1 (a), stage 2 (b), stage 3 (c), and stage 4 (d). Note the perifoveal PVD (arrowheads).
Removing the vitreous is, considering the pathology of macular holes and the need for gas injection at the end of surgery, an ideal and requisite procedure. Nowadays, vitrectomy combined with internal limiting membrane (ILM) peeling is a standard technique for a vitreoretinal surgeon to master during early learning periods. In some cases – like that of the author – the mentor will start teaching by operating on this disease because the procedures encompass most skills required for vitrectomy surgery: core vitrectomy, induction of posterior hyaloid separation, ILM peeling, and gas tamponade. Indications and Preoperative Evaluation
Stage I macular holes sometimes show spontaneous closure during physiological PVD. Hence, they can be followed up with close observation
Idiopathic Macular Hole Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
151
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the perifoveal retina; stage 3 = full-thickness hole with the detached vitreous, in which an operculum is suspended, and stage 4 = fullthickness hole with complete vitreous detachment. More recently, the International Vitreomacular Traction Study (IVTS) Group newly proposed OCT-based anatomic definitions and classification of the closely related vitreomacular diseases and incorporated not only full-thickness macula holes, but also vitreomacular adhesion and vitreomacular traction [9]. In this new proposal, vitreomacular adhesion is defined as perifoveal vitreous separation with remaining vitreomacular attachment and unperturbed foveal morphology. In contrast, vitreomacular traction is characterized by anomalous vitreous detachment accompanied by anatomic distortion of the fovea, including pseudocyst, macular schisis, cystoid macular edema, and subretinal fluid.
Surgical Techniques
Wound Construction In the era of microincision vitrectomy surgery, angled incision is preferred to create the wound for trocar placement [12, 13] because it improves wound sealing and thus prevents postoperative complications such as hypotony and endophthalmitis [14–16]. Even with this technique, however, the sealing is not always complete [17] and wound-related complications can still occur. Therefore, careful detection of the leakage from the wounds is always advised during the removal of trocars, and the surgeon should not hesitate to place a suture if any trace of leakage is detected. One technique for better sealing is to press only the external flap of the wound with a forceps for a few seconds rather than to rub the entire wound back and forth repeatedly, which may conversely lead to reopening and impaired sealing.
152
Core Vitrectomy and Creation of Posterior Hyaloid Separation After the three-port trocar is inserted in place and the infusion cannula is connected, a wideviewing system such as BIOM® (Oculus) or RESIGHT® (Carl Zeiss Meditec) is introduced and then core vitrectomy is commenced. A wide-viewing system is nowadays an indispensable device for modern vitreous surgery since it commands a far wider fundus view compared to the conventional direct-viewing system using contact lenses. It saves the need to suture a fixation ring for contact lens and also makes it much easier for the surgeon to switch between viewing inside the eye and outside the eye – he/she only needs to push aside the metal frame that holds the objective lens. Following core vitrectomy, the peripheral vitreous should also be removed and during this process the illumination needs to be set closer to the cutter probe for better visualization of the vitreal collagen bundles that the surgeon is going to cut. After injecting a small volume of triamcinolone for visualization, posterior hyaloid separation is created by using either a backflush needle or a cutter probe. The latter is more useful in that it can be placed very close to the disc where a strong vitreal adhesion exists and can suck the vitreous from its side. An alternative way of creating the separation is to suck the vitreous cortex between the papillomacular bundle in cases with a high perifoveal PVD documented on preoperative OCT (fig. 2). After hyaloid separation from the posterior pole is achieved, it is important to move the cutter just anteriorly and not tangentially because this may pull the vitreous base and lead to potential formation of retinal breaks. On the other hand, insufficient completion of this step implies the existence of vitreal remnants on the retina, which potentially may lead to postoperative complications such as retinal breaks. Inappropriate completion may also interfere with the more delicate maneuvers like ILM peeling that follows.
Oh Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/17/2015 3:27:22 PM
unless distortion or visual impairment is too severe for patients to tolerate. Stage 2 or higher macular holes are good indications for surgical intervention. Preoperative examination should include visual acuity measurement, the Amsler chart to document and for patients to recognize metamorphopsia, slit-lamp biomicroscopy, and OCT. Especially in stage 2 macular holes, OCT findings are important not only for visualizing the extent of vitreomacular traction, but also for intraoperative maneuvers. If there is marked traction and the flap is highly elevated on OCT, it might be advisable to avoid pulling in the direction, as it could lead to further enlarging of the macular hole during posterior hyaloid separation. Also crucial is to always pay attention to the size of macular holes since they are known to have a substantial influence on anatomical success and visual prognosis [10, 11].
Internal Limiting Membrane Peeling ILM peeling is reported to increase the rate of both primary and final macular hole closure [18–21]. It is also shown that better visual prognosis is achieved at 3 months after surgery [21]. Most surgeons now routinely perform this technique for macular hole surgery. Adjuvants that have been demonstrated to be useful for staining the ILM are indocyanine green [22], triamcinolone acetonide [23], and brilliant blue G (BBG) [24]. Indocyanine green has been reported to be more toxic for the retina than other vital dyes [25, 26]. Triamcinolone acetonide is, strictly speaking, not a vital dye and can be blown away by the irrigation flow. Injected triamcinolone acetonide just attaches to the retina and is then simultaneously removed during ILM peeling and thus contrasting the area of ILM leftover where its particles still remain attached. The author prefers to use BBG, which has been shown to have superior biocompatibility at the concentration normally used [27, 28] (fig. 3). After sufficient staining of ILM, peeling is commenced
Fluid-Air Exchange Fluid-air exchange is performed with a backflush needle. During this process, visualization is usually compromised by the extensive reflex from the fundus, especially when chandelier-type illumination is used. One way to avoid this problem is to reorient the tip of the illumination from the posterior pole to the midperiphery. Changing the illumination color to a longer wave length (e.g. 515 nm) can reduce the extent of fundus reflex and is also a useful way for better visualization. Finally, 1.2 ml of 100% SF6 gas is injected in cases with normal axial length. Intraocular pressure is assured to be relatively soft by palpation. After surgery, the patients are instructed to stay in the face-down position for at least 1 day. The next day, OCT imaging of the gas-filled eye is routinely performed [30] and the lateral position is also allowed with those in whom macular hole closure has been confirmed. If the closure is not assured or the image quality of OCT is not sufficient for evaluation, then the face-down position is maintained for a few more days. So far, the author has not experienced a single case in which macular
Idiopathic Macular Hole Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
153
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Fig. 2. Visualization of posterior vitreous cortex by triamcinolone acetonide injection. Note the two well-stained sites (arrowheads), the bursa premacularis, and space of Martegiani. The cutter probe is placed at the perifoveal PVD, located between the disc and the central fovea, and grasping the posterior vitreal cortex to induce posterior hyaloid separation.
with making a flap by first creating a small cleft on the temporal retinal surface with microvitreoretinal blades or diamond-dusted membrane scrapers. Alternatively, direct grasping of the ILM can be performed with forceps. Since the former is a two-step procedure, the author prefers the latter and has observed no more side effects compared to the former. Moreover, a recent study has shown that the site of postoperatively detected retinal damage does not always coincide with the locations that ILM peeling is initiated [29]. The ILM should first be peeled toward the central fovea and the removal is then enlarged in a fashion similar to that of continuous curvilinear capsulorhexis. After completing ILM peeling, the peripheral retina should be checked carefully and thoroughly for any possible retinal breaks by scleral indentation with a depressor.
a
b
Fig. 3. a Staining of the ILM with BBG (ILM Blue®). Note that the injected BBG solution spontaneously sinks and accumulates within the posterior pole by its gravity since it contains 4% polyethylene glycol as a component. b ILM peeling started by direct grasping using a 27-gauge asymmetrical forceps.
a
b
hole closure was confirmed with sufficient image quality, but later on reopens during the same admission. Recent Advancements
Inverted ILM Peeling Technique Preoperative macular hole size is a critical determinant of anatomic success [10, 31]. To overcome surgical failures in larger-sized macular holes, Michalewska et al. [32] reported a surgical technique called inverted ILM peeling (fig. 4). In
154
their report, the remnant of an incompletely peeled ILM was left and then inverted upsidedown to cover the macular hole. With this technique, they have shown that even in cases with a macular hole size larger than 400 µm the success rate in terms of hole closure reached as high as 98%, whereas the rate obtained with conventional complete ILM peeling was 81%. More recently, Kuriyama et al. [33] reported that this technique also exhibited an excellent success rate in cases of macular holes associated with pathologic myopia.
Oh Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/17/2015 3:27:22 PM
Fig. 4. Inverted ILM peeling. a Preoperative OCT image of a large macular hole with a base diameter of 1,364 µm. b Postoperative OCT image at 3 months showing the ILM remnants completely filled the original hole.
a
b
Postoperative Restoration of Retinal Structures Documented on Optical Coherence Tomography Visual improvement and recovery from distortion are known to be gradual after macular hole surgery; however, the potential mechanisms have not been explored. Wakabayashi et al. [34] reported that based on postoperative OCT findings the recovery of the external limiting membrane line first occur and is then followed by that of the inner segment/outer segment (IS/OS) junction line (fig. 5). They also showed that patients in whom these structures are in good condition tended to have better visual prognosis. Christensen reported that the discontinuity of the IS/OS line with a diameter of more than 1,500 µm 3 months after surgery was associated with poorer visual acuity after 12 months than less extensive discontinuity [35]. In contrast, subfoveal fluid after 3 months had no effect on the final visual outcome in that study. Accordingly, sur-
geons should pay keen attention to these postoperative retinal structures. For the detection ability reason, spectral domain OCT should be used if available. 27-Gauge Vitrectomy System Surgical outcomes of macular hole surgery with microincision vitrectomy surgery have mostly been reported in studies performed with 23- or 25-gauge systems. Sakaguchi et al. [36] first reported that nonvitrectomizing epiretinal membrane removal surgery can be successfully performed with the newly developed smaller 27-gauge system. Later they also demonstrated that most retinal diseases from macular holes extending to more complex cases like proliferative diabetic retinopathy accompanied by tractional retinal detachment can also be managed with similar surgical outcomes and less invasiveness [37]. At the author’s institution, most vitrectomy surgery for macular diseases are currently
Idiopathic Macular Hole Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
155
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Fig. 5. Postoperative changes of outer retinal structure. a Restored external limiting membrane line and discontinuous IS/OS junction line (arrowhead) on OCT 3 months postoperatively. b Continuous lines of both the external limiting membrane and IS/OS on OCT 4 months postoperatively.
a
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performed with the 27-gauge system, and observed as well the features mentioned above (fig. 6). Ocriplasmin Ocriplasmin is a truncated form of human plasmin and has proteolytic activity for components of the vitreoretinal interface including fibronectin and laminin. Recent preclinical and clinical studies have shown that cleaving the bonds between the vitreous and the retina actually has a substantial effect [38–42]. In multicenter, randomized, double-blind, phase III trials, a single
156
intravitreal injection of ocriplasmin (125 µg) significantly showed a better resolution of macular adhesion (26.5 vs. 10.1% in the placebo group) as well as an increased rate of nonsurgical macular hole closure (40.6 vs. 10.6% in the placebo group) [42]. The preoperative factors reported to contribute to better surgical outcomes are absence of epiretinal membrane, adhesion diameter ≤1,500 µm, age
Idiopathic Macular Hole Hideyasu Oh
Abstract Idiopathic macular hole is a disease that arises from adhesion in the vitreomacular interface and can theoretically be treated by vitrectomy surgery. Surgical techniques include removal of the vitreous with or without simultaneous peeling of the internal limiting membrane (ILM), fluid-air exchange, and gas tamponade. Since the advent of microincision vitrectomy surgery, macular hole surgery has been performed with minimal invasiveness, and significant visual improvement is a common outcome. This chapter describes the pathology of this disease, including presurgical evaluation using optical coherence tomography (OCT), and then shows the fundamental techniques required for the surgery. Also important is the understanding of the postsurgical ‘healing’ process of the disease, which may confirm the fact that the subjective improvement is closely related to the retinal imaging obtained by OCT. More recent advances are the inverted ILM peeling technique for larger macular holes and 27-gauge vitrectomy that can potentially minimize the surgical invasiveness mainly by smaller wound construction and the reduced volume of irrigation during surgery. © 2014 S. Karger AG, Basel
Macular holes had long been regarded as an incurable disease until Kelly and Wendel [1, 2] reported that vitrectomy in combination with in-
traocular gas tamponade can be the first modality to treat this disorder with a remarkable success rate. Gass [3, 4] first reported the potential pathogenesis of idiopathic macular holes based on biomicroscopic findings. He proposed that the vitreous cortex remaining on the macula after spontaneous posterior vitreous separation will contract and lead to tear formation at the macula in an eccentric fashion. After the advent of optical coherence tomography (OCT), investigators were able to show the presence of localized vitreomacular adhesion at the central fovea in stage 1 and stage 2 macular holes [5, 6]. The adhesion is surrounded by a shallow posterior hyaloid separation [called perifoveal posterior vitreous detachment (PVD)] [5, 7], and its existence has convinced observers that anteroposterior traction also plays a crucial role in pathogenesis [8]. Based on these key findings, researchers adopted a OCT-based classification of macular holes, which is highly compatible in clinical settings (fig. 1): stage 1a = retinal split, foveal cyst or foveal detachment with a vitreous cortex attachment to the fovea; stage 1b = dehiscence of photoreceptor layer with a vitreous cortex attachment to the fovea; stage 2 = full-thickness hole covered by a flap-like tissue extending from
Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/17/2015 3:27:22 PM
Hyogo Prefectural Amagasaki Hospital, Amagasaki, Hyogo, Japan
a
b
c
d
Fig. 1. Spectral domain OCT image of macular holes: stage 1 (a), stage 2 (b), stage 3 (c), and stage 4 (d). Note the perifoveal PVD (arrowheads).
Removing the vitreous is, considering the pathology of macular holes and the need for gas injection at the end of surgery, an ideal and requisite procedure. Nowadays, vitrectomy combined with internal limiting membrane (ILM) peeling is a standard technique for a vitreoretinal surgeon to master during early learning periods. In some cases – like that of the author – the mentor will start teaching by operating on this disease because the procedures encompass most skills required for vitrectomy surgery: core vitrectomy, induction of posterior hyaloid separation, ILM peeling, and gas tamponade. Indications and Preoperative Evaluation
Stage I macular holes sometimes show spontaneous closure during physiological PVD. Hence, they can be followed up with close observation
Idiopathic Macular Hole Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
151
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the perifoveal retina; stage 3 = full-thickness hole with the detached vitreous, in which an operculum is suspended, and stage 4 = fullthickness hole with complete vitreous detachment. More recently, the International Vitreomacular Traction Study (IVTS) Group newly proposed OCT-based anatomic definitions and classification of the closely related vitreomacular diseases and incorporated not only full-thickness macula holes, but also vitreomacular adhesion and vitreomacular traction [9]. In this new proposal, vitreomacular adhesion is defined as perifoveal vitreous separation with remaining vitreomacular attachment and unperturbed foveal morphology. In contrast, vitreomacular traction is characterized by anomalous vitreous detachment accompanied by anatomic distortion of the fovea, including pseudocyst, macular schisis, cystoid macular edema, and subretinal fluid.
Surgical Techniques
Wound Construction In the era of microincision vitrectomy surgery, angled incision is preferred to create the wound for trocar placement [12, 13] because it improves wound sealing and thus prevents postoperative complications such as hypotony and endophthalmitis [14–16]. Even with this technique, however, the sealing is not always complete [17] and wound-related complications can still occur. Therefore, careful detection of the leakage from the wounds is always advised during the removal of trocars, and the surgeon should not hesitate to place a suture if any trace of leakage is detected. One technique for better sealing is to press only the external flap of the wound with a forceps for a few seconds rather than to rub the entire wound back and forth repeatedly, which may conversely lead to reopening and impaired sealing.
152
Core Vitrectomy and Creation of Posterior Hyaloid Separation After the three-port trocar is inserted in place and the infusion cannula is connected, a wideviewing system such as BIOM® (Oculus) or RESIGHT® (Carl Zeiss Meditec) is introduced and then core vitrectomy is commenced. A wide-viewing system is nowadays an indispensable device for modern vitreous surgery since it commands a far wider fundus view compared to the conventional direct-viewing system using contact lenses. It saves the need to suture a fixation ring for contact lens and also makes it much easier for the surgeon to switch between viewing inside the eye and outside the eye – he/she only needs to push aside the metal frame that holds the objective lens. Following core vitrectomy, the peripheral vitreous should also be removed and during this process the illumination needs to be set closer to the cutter probe for better visualization of the vitreal collagen bundles that the surgeon is going to cut. After injecting a small volume of triamcinolone for visualization, posterior hyaloid separation is created by using either a backflush needle or a cutter probe. The latter is more useful in that it can be placed very close to the disc where a strong vitreal adhesion exists and can suck the vitreous from its side. An alternative way of creating the separation is to suck the vitreous cortex between the papillomacular bundle in cases with a high perifoveal PVD documented on preoperative OCT (fig. 2). After hyaloid separation from the posterior pole is achieved, it is important to move the cutter just anteriorly and not tangentially because this may pull the vitreous base and lead to potential formation of retinal breaks. On the other hand, insufficient completion of this step implies the existence of vitreal remnants on the retina, which potentially may lead to postoperative complications such as retinal breaks. Inappropriate completion may also interfere with the more delicate maneuvers like ILM peeling that follows.
Oh Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/17/2015 3:27:22 PM
unless distortion or visual impairment is too severe for patients to tolerate. Stage 2 or higher macular holes are good indications for surgical intervention. Preoperative examination should include visual acuity measurement, the Amsler chart to document and for patients to recognize metamorphopsia, slit-lamp biomicroscopy, and OCT. Especially in stage 2 macular holes, OCT findings are important not only for visualizing the extent of vitreomacular traction, but also for intraoperative maneuvers. If there is marked traction and the flap is highly elevated on OCT, it might be advisable to avoid pulling in the direction, as it could lead to further enlarging of the macular hole during posterior hyaloid separation. Also crucial is to always pay attention to the size of macular holes since they are known to have a substantial influence on anatomical success and visual prognosis [10, 11].
Internal Limiting Membrane Peeling ILM peeling is reported to increase the rate of both primary and final macular hole closure [18–21]. It is also shown that better visual prognosis is achieved at 3 months after surgery [21]. Most surgeons now routinely perform this technique for macular hole surgery. Adjuvants that have been demonstrated to be useful for staining the ILM are indocyanine green [22], triamcinolone acetonide [23], and brilliant blue G (BBG) [24]. Indocyanine green has been reported to be more toxic for the retina than other vital dyes [25, 26]. Triamcinolone acetonide is, strictly speaking, not a vital dye and can be blown away by the irrigation flow. Injected triamcinolone acetonide just attaches to the retina and is then simultaneously removed during ILM peeling and thus contrasting the area of ILM leftover where its particles still remain attached. The author prefers to use BBG, which has been shown to have superior biocompatibility at the concentration normally used [27, 28] (fig. 3). After sufficient staining of ILM, peeling is commenced
Fluid-Air Exchange Fluid-air exchange is performed with a backflush needle. During this process, visualization is usually compromised by the extensive reflex from the fundus, especially when chandelier-type illumination is used. One way to avoid this problem is to reorient the tip of the illumination from the posterior pole to the midperiphery. Changing the illumination color to a longer wave length (e.g. 515 nm) can reduce the extent of fundus reflex and is also a useful way for better visualization. Finally, 1.2 ml of 100% SF6 gas is injected in cases with normal axial length. Intraocular pressure is assured to be relatively soft by palpation. After surgery, the patients are instructed to stay in the face-down position for at least 1 day. The next day, OCT imaging of the gas-filled eye is routinely performed [30] and the lateral position is also allowed with those in whom macular hole closure has been confirmed. If the closure is not assured or the image quality of OCT is not sufficient for evaluation, then the face-down position is maintained for a few more days. So far, the author has not experienced a single case in which macular
Idiopathic Macular Hole Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
153
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Fig. 2. Visualization of posterior vitreous cortex by triamcinolone acetonide injection. Note the two well-stained sites (arrowheads), the bursa premacularis, and space of Martegiani. The cutter probe is placed at the perifoveal PVD, located between the disc and the central fovea, and grasping the posterior vitreal cortex to induce posterior hyaloid separation.
with making a flap by first creating a small cleft on the temporal retinal surface with microvitreoretinal blades or diamond-dusted membrane scrapers. Alternatively, direct grasping of the ILM can be performed with forceps. Since the former is a two-step procedure, the author prefers the latter and has observed no more side effects compared to the former. Moreover, a recent study has shown that the site of postoperatively detected retinal damage does not always coincide with the locations that ILM peeling is initiated [29]. The ILM should first be peeled toward the central fovea and the removal is then enlarged in a fashion similar to that of continuous curvilinear capsulorhexis. After completing ILM peeling, the peripheral retina should be checked carefully and thoroughly for any possible retinal breaks by scleral indentation with a depressor.
a
b
Fig. 3. a Staining of the ILM with BBG (ILM Blue®). Note that the injected BBG solution spontaneously sinks and accumulates within the posterior pole by its gravity since it contains 4% polyethylene glycol as a component. b ILM peeling started by direct grasping using a 27-gauge asymmetrical forceps.
a
b
hole closure was confirmed with sufficient image quality, but later on reopens during the same admission. Recent Advancements
Inverted ILM Peeling Technique Preoperative macular hole size is a critical determinant of anatomic success [10, 31]. To overcome surgical failures in larger-sized macular holes, Michalewska et al. [32] reported a surgical technique called inverted ILM peeling (fig. 4). In
154
their report, the remnant of an incompletely peeled ILM was left and then inverted upsidedown to cover the macular hole. With this technique, they have shown that even in cases with a macular hole size larger than 400 µm the success rate in terms of hole closure reached as high as 98%, whereas the rate obtained with conventional complete ILM peeling was 81%. More recently, Kuriyama et al. [33] reported that this technique also exhibited an excellent success rate in cases of macular holes associated with pathologic myopia.
Oh Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/17/2015 3:27:22 PM
Fig. 4. Inverted ILM peeling. a Preoperative OCT image of a large macular hole with a base diameter of 1,364 µm. b Postoperative OCT image at 3 months showing the ILM remnants completely filled the original hole.
a
b
Postoperative Restoration of Retinal Structures Documented on Optical Coherence Tomography Visual improvement and recovery from distortion are known to be gradual after macular hole surgery; however, the potential mechanisms have not been explored. Wakabayashi et al. [34] reported that based on postoperative OCT findings the recovery of the external limiting membrane line first occur and is then followed by that of the inner segment/outer segment (IS/OS) junction line (fig. 5). They also showed that patients in whom these structures are in good condition tended to have better visual prognosis. Christensen reported that the discontinuity of the IS/OS line with a diameter of more than 1,500 µm 3 months after surgery was associated with poorer visual acuity after 12 months than less extensive discontinuity [35]. In contrast, subfoveal fluid after 3 months had no effect on the final visual outcome in that study. Accordingly, sur-
geons should pay keen attention to these postoperative retinal structures. For the detection ability reason, spectral domain OCT should be used if available. 27-Gauge Vitrectomy System Surgical outcomes of macular hole surgery with microincision vitrectomy surgery have mostly been reported in studies performed with 23- or 25-gauge systems. Sakaguchi et al. [36] first reported that nonvitrectomizing epiretinal membrane removal surgery can be successfully performed with the newly developed smaller 27-gauge system. Later they also demonstrated that most retinal diseases from macular holes extending to more complex cases like proliferative diabetic retinopathy accompanied by tractional retinal detachment can also be managed with similar surgical outcomes and less invasiveness [37]. At the author’s institution, most vitrectomy surgery for macular diseases are currently
Idiopathic Macular Hole Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 150–158 (DOI: 10.1159/000360461)
155
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Fig. 5. Postoperative changes of outer retinal structure. a Restored external limiting membrane line and discontinuous IS/OS junction line (arrowhead) on OCT 3 months postoperatively. b Continuous lines of both the external limiting membrane and IS/OS on OCT 4 months postoperatively.
a
b
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–5.00 µm
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240
270
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performed with the 27-gauge system, and observed as well the features mentioned above (fig. 6). Ocriplasmin Ocriplasmin is a truncated form of human plasmin and has proteolytic activity for components of the vitreoretinal interface including fibronectin and laminin. Recent preclinical and clinical studies have shown that cleaving the bonds between the vitreous and the retina actually has a substantial effect [38–42]. In multicenter, randomized, double-blind, phase III trials, a single
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intravitreal injection of ocriplasmin (125 µg) significantly showed a better resolution of macular adhesion (26.5 vs. 10.1% in the placebo group) as well as an increased rate of nonsurgical macular hole closure (40.6 vs. 10.6% in the placebo group) [42]. The preoperative factors reported to contribute to better surgical outcomes are absence of epiretinal membrane, adhesion diameter ≤1,500 µm, age
