Aqueous Shunt Exposure
Purpose: To describe the patient outcomes and factors affecting those outcomes after aqueous shunt exposure repair.
Patients and Methods: Forty-three eyes from Robert Cizik Eye Clinic and Bascom Palmer Eye Institute from 1995 to 2007 suffered from aqueous shunt exposure and were repaired by participating surgeons. Thirty-three were tube exposures and 7 were plate exposures. The remaining 3 exposure classified complications included a patch graft exposure, an elbow exposure, and 1 unknown complication. Forty eyes were followed for evidence of additional aqueous shunt exposures or additional surgical interventions for 46.6 weeks (40.2 wk) (range: 3 to 168 wk).
Results: Seventeen of 40 eyes required additional surgical intervention: 15 (45%) from the tube exposure group and 2 (29%) from the plate exposure group. Five (13%) eyes needed eventual removal of the shunt. Black race, diabetes mellitus, a high number of glaucoma medications before shunt implantation, a history of multiple glaucoma laser procedures, and combination of an initial aqueous shunt implantation with another surgery were found to be associated with a worse outcome after exposure repair.
Conclusions: Intraocular pressure, number of medications, and visual acuity remained stable during follow-up after revision. Diabetes mellitus was associated with a shorter average time between initial repair and reintervention, and 4 other variables were associated with a higher likelihood of reintervention.
Aqueous shunts have been shown to be a successful way to control intraocular pressure (IOP), leading to an increasing rate of their use over the past 15 years. However, owing to the nature of the procedure, aqueous shunts have some unique complications that can result in serious consequences for the eye.
Whenever a foreign device is surgically installed into the human body, a risk exists that overlying tissue erosion may lead to device exposure. The same is true for aqueous shunt endplates and tubes. Exposures of either tubes or plates are very different problems, but they may share similar physiologic causes. Tube exposure may be the end result of patch graft thinning because of excessive tension overlying the tube or from an immune-mediated inflammatory process. Other possible causes of plate or tube exposure may include ischemic damage to the conjunctiva or the repeated mechanical force caused by the eyelid blinking. The link between aqueous shunt tube exposure and endophthalmitis is well established, reinforcing the need for immediate repair.
Unfortunately, our clinical experience tells us that aqueous shunt exposure repairs fail at a high rate, and each re-exposure requires another intervention to prevent infection or loss of vision. Moreover, plate exposures are harder to correct, and if infection is suspected, the best solution may be to remove the aqueous shunt.
To date, there are no published reports that investigate the factors associated with the successful first repair of tube or plate exposures or complications associated with the repair. In this retrospective case series, we evaluate the outcomes of initial (first) surgical revision for aqueous shunt exposures in 43 eyes and investigate potential risk factors leading to complications and a need for an additional surgery after initial repair.
Abstract and Introduction
Abstract
Purpose: To describe the patient outcomes and factors affecting those outcomes after aqueous shunt exposure repair.
Patients and Methods: Forty-three eyes from Robert Cizik Eye Clinic and Bascom Palmer Eye Institute from 1995 to 2007 suffered from aqueous shunt exposure and were repaired by participating surgeons. Thirty-three were tube exposures and 7 were plate exposures. The remaining 3 exposure classified complications included a patch graft exposure, an elbow exposure, and 1 unknown complication. Forty eyes were followed for evidence of additional aqueous shunt exposures or additional surgical interventions for 46.6 weeks (40.2 wk) (range: 3 to 168 wk).
Results: Seventeen of 40 eyes required additional surgical intervention: 15 (45%) from the tube exposure group and 2 (29%) from the plate exposure group. Five (13%) eyes needed eventual removal of the shunt. Black race, diabetes mellitus, a high number of glaucoma medications before shunt implantation, a history of multiple glaucoma laser procedures, and combination of an initial aqueous shunt implantation with another surgery were found to be associated with a worse outcome after exposure repair.
Conclusions: Intraocular pressure, number of medications, and visual acuity remained stable during follow-up after revision. Diabetes mellitus was associated with a shorter average time between initial repair and reintervention, and 4 other variables were associated with a higher likelihood of reintervention.
Introduction
Aqueous shunts have been shown to be a successful way to control intraocular pressure (IOP), leading to an increasing rate of their use over the past 15 years. However, owing to the nature of the procedure, aqueous shunts have some unique complications that can result in serious consequences for the eye.
Whenever a foreign device is surgically installed into the human body, a risk exists that overlying tissue erosion may lead to device exposure. The same is true for aqueous shunt endplates and tubes. Exposures of either tubes or plates are very different problems, but they may share similar physiologic causes. Tube exposure may be the end result of patch graft thinning because of excessive tension overlying the tube or from an immune-mediated inflammatory process. Other possible causes of plate or tube exposure may include ischemic damage to the conjunctiva or the repeated mechanical force caused by the eyelid blinking. The link between aqueous shunt tube exposure and endophthalmitis is well established, reinforcing the need for immediate repair.
Unfortunately, our clinical experience tells us that aqueous shunt exposure repairs fail at a high rate, and each re-exposure requires another intervention to prevent infection or loss of vision. Moreover, plate exposures are harder to correct, and if infection is suspected, the best solution may be to remove the aqueous shunt.
To date, there are no published reports that investigate the factors associated with the successful first repair of tube or plate exposures or complications associated with the repair. In this retrospective case series, we evaluate the outcomes of initial (first) surgical revision for aqueous shunt exposures in 43 eyes and investigate potential risk factors leading to complications and a need for an additional surgery after initial repair.
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