Complications of Glaucoma Surgery

2013 ◽  
Keyword(s):  
Wound Healing ◽  
Glaucoma Surgery ◽  
Filtering Surgery ◽  
Shunt Implantation ◽  
Tube Shunt ◽  
Healing Processes

Glaucoma surgery is difficult and fraught with complications. Some complications are common and mild, while others are rare and/or vision threatening. However, good outcomes are still likely if those complications encountered are managed properly. This book is intended for those surgeons wishing to improve their skills and abilities to manage difficult problems that will come up during the care of glaucoma patients. Comprising seven comprehensive sections, chapters in this volume address outflow mechanisms after glaucoma surgery, wound healing processes and modulators, complications in filtering surgery, tube shunt implantation, and angle procedures, among other topics. The authors of each chapter provide surgical and clinical pearls not only for managing difficulties but in preventing them as well. Additionally, because each surgeon has their own way of addressing a particular situation, there is commentary at the end of each chapter to provide another opinion or strategy for dealing with a particular surgical scenario. Cross-referencing is provided throughout this book to direct the reader to as many helpful sections as possible. Both thorough and highly-illustrative, this book will help both new and experienced glaucoma surgeons deal with complications and provide successful results for their patients.

Tube Shunt Related Complications of the Orbit

2013 ◽  
Author(s):  
Marc R. Criden
Keyword(s):  
Glaucoma Surgery ◽  
Shunt Surgery ◽  
Ocular Surgery ◽  
Significant Treatment ◽  
Mechanical Complications ◽  
Surface Areas ◽  
Eyelid Edema ◽  
Shunt Implantation ◽  
Orbital Complications ◽  
Tube Shunt

Orbital complications during or after glaucoma filtering or tube shunt surgery are relatively rare but may pose a significant treatment challenge or threat to vision. The incidence of complications is highly variable, and transient events may not be reported as frequently as those that persist. A variety of orbital complications occur following glaucoma surgery. Complications may be categorized as mechanical, infectious, neurogenic, or myogenic. However, each complication may be multimodal and fall into more than one category. Mechanical complications are the most frequent type of orbit complication related to glaucoma surgery and more specifically to tube shunt implantation. Mechanical complications include ptosis, lid retraction, strabismus, and proptosis. Several theories address why ptosis may occur after ocular surgery and why it may be either transient or permanent. The levator muscle may be damaged or dehisced by an eyelid speculum, leading to a lid droop. Bridle sutures, which are often used during glaucoma surgery, have also been implicated as they apply counter traction against the superior rectus muscle. Prolonged eyelid edema and local anesthesia have each been more strongly associated with postoperative ptosis. For more information on ptosis, see Chapter 25. Strabismus after tube shunt implantation is most commonly related to either the device itself or to scarring and fibrosis that develop postoperatively. Transient strabismus may be related to swelling or edema of local tissues and may also follow retrobulbar injection. The strabismus is usually incomitant and does not present with a characteristic pattern of deviation; thus, prisms and other nonsurgical treatments are seldom adequate. Although strabismus following tube shunt surgery is usually transient, persistent diplopia may occur. The type of implant, size, location, and material each play a role. Implants with larger surface areas have a higher incidence of motility disturbance due to mass effect. Tube shunt plates that require placement below the rectus muscles risk direct muscle injury or adhesion scarring to the implant. In addition, a pseudo-Brown’s syndrome may be created by a superonasal implant due to interference with the superior oblique muscle function. The bleb that develops around the tube shunt reservoir can also act as a mass.

Trabeculectomy and Tube Shunts

2013 ◽  
Author(s):  
Darrell WuDunn
Keyword(s):  
Wound Healing ◽  
Glaucoma Surgery ◽  
Aqueous Fluid ◽  
Filtering Bleb ◽  
Schlemm's Canal ◽  
Healing Response ◽  
Subconjunctival Space ◽  
Wound Healing Response ◽  
Tube Shunt ◽  
Aqueous Outflow

Trabeculectomy surgery is the most common operative procedure for managing glaucoma. Although the techniques have evolved over the decades, the basic procedure remains the same since filtering surgery was first performed a century ago: a scleral fistula enables aqueous fluid to drain into the subconjunctival space and create a bleb. Despite the long history of trabeculectomy surgery, the mechanisms of how aqueous fluid ultimately exits the eye after trabeculectomy are still not well characterized. Aqueous tube shunts are becoming more popular among glaucoma surgeons as an alternative to trabeculectomy in eyes with previously failed blebs or in eyes at high risk for bleb failure. Although the mechanism of aqueous outflow following tube shunt implantation may be similar to the mechanism after trabeculectomy, key differences exist that may be important for future developments in glaucoma surgery. Multiple potential routes of aqueous drainage exist for both trabeculectomy and tube shunt implants. Thus, aqueous drainage can be thought of as a complex system of pathways arranged in series and in parallel. In general, fluid flowing through any system will be directed according to the resistance along each potential pathway. After glaucoma surgery, the arrangement and resistance through these pathways will depend on the wound healing response (see Chapter 3), and thus the mechanism of aqueous drainage will alter as the wound healing response evolves. However, it is likely that one or 2 main routes of drainage will dominate as the tissue reaction stabilizes. When Cairns first described the trabeculectomy procedure, he argued that aqueous humor would flow out through the cut ends of Schlemm’s canal without subconjunctival drainage. However, as the procedure is currently performed, a filtering bleb is almost always created, and a block of trabecular meshwork is not consistently excised. Thus, modern trabeculectomy is a filtering procedure in which aqueous passes through the sclera into the subconjunctival space overlying the scleral flap. The existence of a filtering bleb does not eliminate the possibility of aqueous outflow through Schlemm’s canal into the aqueous veins. Indeed, tracer studies suggest that some aqueous enters the aqueous veins.

Diplopia and Ocular Motility Disturbances

2013 ◽  
Author(s):  
Amir A. Pirouzian
Keyword(s):  
Surgical Complication ◽  
Case Series ◽  
Glaucoma Surgery ◽  
Mass Effect ◽  
Ocular Motility ◽  
Flexible Plate ◽  
Shunt Implantation ◽  
Device Use ◽  
A Minor ◽  
Tube Shunt

Strabismus and diplopia have been reported with tube shunt implants in glaucoma surgery in several case series. Overall, the reports of strabismus (vertical and horizontal) as a potentially disabling surgical complication widely range from 5% to 100% depending on the type of tube shunt used. The challenge in determining the exact incidence of strabismus after tube shunt implantation arises from a lack of accurate preoperative strabismus evaluation and documentation in the published studies, as well as a higher incidence of reduced peripheral fusion and visual acuity in these selected groups of patients. The mechanism of postoperative strabismus is likely due to one of the following: 1) the size and the height of the device inserted and the resulting mass effect (bleb size); 2) the technique of surgical placement; 3) postoperative surgical adhesion, scar formation, and restriction; 4) probable muscle ischemia in conjunction with antifibrotic agents; 5) fat adherence syndrome; and 6) muscle-tendon stretching. Understanding the mechanism of strabismus is important for prevention and treatment of this condition. The mass effect following tube shunt implantation has been noted in multiple studies however, the true pathophysiology remains unclear. A proposed mechanism of postoperative ocular dysmotility suggests a direct mass effect on the extraocular muscles (EOM) from the implant or the encapsulated cystic bleb surrounding the device. Use of a large device or creation of a highly elevated bleb may shift an EOM pulley from its original anatomical pathway, thus creating a heterotopic pulley phenomenon. Therefore extreme caution and thorough preoperative counseling should be exercised in those patients with an already restricted peripheral sensory fusion because even a minor shift in extraocular muscle alignment may compromise the patient’s ability to maintain fusion and trigger the development of a secondary strabismus. Selection of the smallest device for an appropriate reduction of intraocular pressure (IOP) is also strongly advised in such patients. The newer generation of Baerveldt® implants with fenestrated plates (Abbot Medical Optics, Inc., Santa Ana, California) and flexible plate Ahmed™ valves (New World Medical, Inc., Rancho Cucamonga, California) may result in a lower bleb height, which will decrease the compressive effect on an individual EOM and its pulley system.

scholarly journals A New Angle on Angle Surgery

2017 ◽  
Vol 11 (01) ◽  
pp. 40
Author(s):  
Rhys Davies ◽  
Mei-Ling Cheng ◽  
Andrew J Tatham ◽  
◽  
◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
High Risk ◽  
Visual Loss ◽  
Glaucoma Surgery ◽  
Filtering Surgery ◽  
Advanced Glaucoma ◽  
Outflow Pathway ◽  
Tube Shunt ◽  
Aqueous Outflow ◽  
Ab Interno

Glaucoma surgery has long relied on ab externo techniques such as augmented trabeculectomy and tube-shunt procedures. While these have excellent potential to lower intraocular pressure (IOP), they are associated with risks, including hypotony, and are therefore conventionally reserved for those with advanced glaucoma or at high risk of visual loss. Traditional filtering surgery attempts to bypass the eye’s physiological outflow pathway, however new minimally invasive glaucoma surgery (MIGS) procedures have recently been introduced that focus on the angle structures as a target for improving aqueous outflow. There are a growing number of ab interno MIGS procedures that utilise the natural drainage pathways of the eye in the management of glaucoma. This article examines the progress so far and describes how the angle has become a viable target for glaucoma surgery.

Wound Healing Modulation in Glaucoma Filtering Surgery

2004 ◽  
Vol 44 (2) ◽  
pp. 61-106 ◽  
Author(s):  
Sean-Paul A. Atreides ◽  
Gregory L. Skuta ◽  
Adam C. Reynolds
Keyword(s):  
Wound Healing ◽  
Filtering Surgery

scholarly journals A Disposable Photovoltaic Patch Controlling Cellular Microenvironment for Wound Healing

2018 ◽  
Vol 19 (10) ◽  
pp. 3025 ◽  
Author(s):  
Hyeon-Ki Jang ◽  
Jin Oh ◽  
Gun-Jae Jeong ◽  
Tae-Jin Lee ◽  
Gwang-Bum Im ◽  
...  
Keyword(s):  
Wound Healing ◽  
Large Scale ◽  
Healing Process ◽  
Skin Wound ◽  
Myoblast Differentiation ◽  
Wound Healing Process ◽  
Light Illumination ◽  
Cellular Microenvironment ◽  
Healing Processes

Electrical stimulation (ES) is known to affect the wound healing process by modulating skin cell behaviors. However, the conventional clinical devices that can generate ES for promoting wound healing require patient hospitalization due to large-scale of the extracorporeal devices. Herein, we introduce a disposable photovoltaic patch that can be applied to skin wound sites to control cellular microenvironment for promoting wound healing by generating ES. In vitro experiment results show that exogenous ES could enhance cell migration, proliferation, expression of extracellular matrix proteins, and myoblast differentiation of fibroblasts which are critical for wound healing. Our disposable photovoltaic patches were attached to the back of skin wound induced mice. Our patch successfully provided ES, generated by photovoltaic energy harvested from the organic solar cell under visible light illumination. In vivo experiment results show that the patch promoted cutaneous wound healing via enhanced host-inductive cell proliferation, cytokine secretion, and protein synthesis which is critical for wound healing process. Unlike the current treatments for wound healing that engage passive healing processes and often are unsuccessful, our wearable photovoltaic patch can stimulate regenerative activities of endogenous cells and actively contribute to the wound healing processes.

Scleral Perforation

2013 ◽  
Author(s):  
Jorge L. Rivera-Velez
Keyword(s):  
Rare Complication ◽  
Scleral Buckling ◽  
Shunt Surgery ◽  
Santa Ana ◽  
Shunt Implantation ◽  
Increased Risk ◽  
Shunt Group ◽  
Risk Patients ◽  
Tube Versus ◽  
Tube Shunt

Scleral perforation during tube shunt implantation is a rare complication. In a recent publication of the Tube Versus Trabeculectomy Study, 3 out of 107 patients in the tube shunt group had scleral perforation during placement of a device. Merino-de-Palacios et al reported scleral perforation during tube shunt surgery in 1 of 86 eyes. The type of device used does not seem to be important in the incidence of scleral perforation. In the Tube Versus Trabeculectomy Study, Baerveldt® devices (Abbott Medical Optics, Inc., Santa Ana, California) were used exclusively, and Ahmed™ Glaucoma Valves (New World Medical, Inc., Rancho Cucamonga, California) and Molteno® implants (Molteno Ophthalmic, Ltd., Dunedin, New Zealand) were used in the study by Merino-de-Palacios et al. Serious sequelae, such as endophthalmitis or retinal detachment, have not been reported in recent literature following scleral perforation during tube shunt placement; nonetheless, this complication should be prevented and, if it does occur, managed promptly. Patients who are believed to have an increased risk for scleral perforation are myopic patients (>-6.00 D) and patients with previous extraocular muscle surgery. Patients with previous scleral buckle surgery, autoimmune diseases, scleritis, or any other conditions that cause or perpetuate thinning of the sclera potentially increase the risk. Patients with previous scleral buckling procedures who require tube shunt surgery will benefit from having the device anchored behind the buckle or directly over the buckle. No attempt should be made to dissect under the buckling device, as dissection may lead to the buckle anchoring sutures perforating the eye. The most common site for tube shunt implantation is the superotemporal quadrant, between the superior and lateral rectus muscles. This location offers the benefit of having the implant hidden under the superior eyelid, no oblique muscles in the region, and better intraoperative exposure, allowing the surgeon to place the implant farther from the limbus. The plate of the implant is usually attached to the sclera approximately 8–10 mm posterior to the limbus. This is also the thinnest portion of the sclera. Exposure when implanting the tube shunt is probably the most important factor in avoiding scleral perforation.

Tube Shunt Surgery Versus Trabeculectomy in Eyes with Prior Ocular Surgery and Uncontrolled Glaucoma

2020 ◽  
pp. 103-108
Author(s):  
Alan D. Penman ◽  
Kimberly W. Crowder ◽  
William M. Watkins
Keyword(s):  
Mitomycin C ◽  
Medical Therapy ◽  
Cataract Extraction ◽  
Glaucoma Surgery ◽  
Shunt Surgery ◽  
Ocular Surgery ◽  
Lens Implantation ◽  
Surgical Options ◽  
Tube Versus ◽  
Tube Shunt

The Tube Versus Trabeculectomy (TVT) Study was a randomized clinical trial comparing tube shunt surgery to trabeculectomy with mitomycin C in patients with uncontrolled glaucoma (intraocular pressure (IOP) ≥18 mm Hg and ≤40 mm Hg on maximum tolerated medical therapy) who had previously undergone cataract extraction with intraocular lens implantation and/or failed filtering surgery. The study did not demonstrate clear superiority of one glaucoma operation over the other, but indicated that both tube shunt surgery and trabeculectomy with mitomycin C were viable surgical options for treating medically uncontrolled glaucoma in this group of patients. Both procedures were associated with similar IOP reduction and use of supplemental medical therapy at 5 years. Additional glaucoma surgery was needed more frequently after trabeculectomy with MMC than tube shunt placement.

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