Tube Shunt Related Complications in Pediatrics

Although medical therapy is usually an excellent therapeutic option in the adult population, in children it is often ineffective or associated with an undesirable risk:benefit ratio. Therefore, surgical intervention is frequently required for adequate control of glaucoma in young patients. The initial surgical approach for management of glaucoma in children includes goniotomy and trabeculotomy, each with a high success rate. When these interventions fail or have a high likelihood of failure (i.e., in patients with Sturge-Weber syndrome, aniridia, anterior chamber dysgenesis, or congenital glaucoma), tube shunt procedures are often required. Tube shunts were first used in the pediatric population by Molteno and colleagues in 1973 and have since grown in popularity and secured an integral role in the treatment of refractory glaucoma in infants and children. Possible complications and causes for failure of tube shunt devices in children are very similar to those in adults; however, issues such as tube migration and retraction must be anticipated in the child’s growing eye. One of the most frustrating, and unfortunately the most common, complications is tube malposition. While tube malposition is not entirely specific to the pediatric population, it occurs far more frequently in children than in adults. (See Chapter 30 for information about tube malposition in adults.) Incidence of tube malposition in pediatric patients ranges from 3% to 35%. In infants and young children, the tube tends to retract from the eye and/or migrate towards the cornea in the anterior chamber. The initial presentation of tube migration is often tube-cornea touch at the proximal end of the tube near the insertion site. In severe cases, tube migration can lead to transcorneal extrusion of the tube. Secondary complications, including corneal decompensation, cataract, iris abnormalities, and endophthalmitis, can result from these initial insults if tube malposition is not identified early and appropriately addressed. The cause of tube migration and retraction is likely multifactorial, but there are 2 basic mechanisms thought to be at fault: 1) somatic growth causing concomitant tube migration and 2) elasticity of the buphthalmic eye, allowing shrinkage as intraocular pressure (IOP) decreases and tube straightening due to “memory.”