Shunt Surgery Tube-shunt surgery, or Seton tube shunt glaucoma surgery, is a surgical method to treat glaucoma. Glaucoma is a potentially blinding disease affecting 2–3% of the United States population. The major known cause of glaucoma is a relative increase in intraocular pressure, or IOP.
The purpose of glaucoma treatment, whether medical or surgical, is to lower the IOP. Aqueous fluid is made continuously, and circulates throughout the eye before draining though channels in the eye's anterior chamber. When too much fluid is made, or it is not drained sufficiently, the IOP rises.
This fluid build-up can lead to glaucoma. Normal intraocular pressure is under 21 mm/Hg. Glaucoma develops at IOPs higher than 21mm/Hg.
However, approximately 20% of glaucoma patients never have pressures higher than 21 mm/Hg. Seton tube implants are also called glaucoma drainage tubes or implants. The Seton implant is comprised of two parts:Tubing, a portion of which is implanted along the inside of the front of the eye.
The distal (furthest from the center) end of the tubing protrudes through the anterior (front) or less commonly, the posterior (rear), chamber of the eye. An attached reservoir, called a plate, is placed under the conjunctiva of the eye at its equator, or midpoint. PurposeThe function of the implant is to lower the intraocular pressure by filtering excess aqueous fluid out of the eye.
During the first few weeks after surgery, a bleb of fibrous tissue and collagen forms around the plate of the implant. The formation of a filtration bleb is essential for filtering the excessive aqueous fluid. The thickness of the bleb, as well as the size or number of plates, determines the rate at which aqueous flows out of the anterior chamber of the eye.
The excess aqueous fluid is shunted through the tubing of the implant, and passes through the space that develops between the bleb and the plate. By diffusion, the fluid flows into the capillaries where it exits the eye and enters general circulation. The IOP is lowered as a result of this decrease in fluid.
There are various types of implants used in glaucoma surgery. They fall into two categories: the non-valved (free flow implants) and valved (resisted-flow implants). One of the first free-flow implants was the Molteno implant, which consists of one or two polypropylene reservoirs connected to a silicone tube.
The non-valved Baerveldt implant is larger than the Molteno, and is available in three sizes. The restrictive implants, which include the Krupin and Ahmed implant, have valves that automatically close if the intraocular pressure is too low. This is important because in the first few weeks after surgery (before the bleb forms), the aqueous fluid can flow unimpeded through the implant.As a result, hypotony (low level of fluid in the eye) can develop.
Newer implants such as the Express shunt and the Gore-Tex tube shunt are in early stages of use. DemographicsSeton tube implants are employed to treat all forms of glaucoma, but are primarily used in patients with elevated IOP despite aggressive medical treatment. They are also used when other types of surgery, such as conventional filtration, or trabeculectomy, have not been successful, or would not be recommended.
A trabeculectomy should not be performed on patients with neovascular glaucoma, as well as those who have ocular complications caused by previous glaucoma surgeries. Implants are often placed in the eyes of patients with uveitic glaucoma (fluctuating IOP). The surgeon implants a tube with a ligature, and manipulates the ligature to control pressure.
Seton tubes are also used in young patients with aniridia, who often develop glaucoma. These tubes should not be used for patients who have silicon oil implants for the treatment of retinal detachment. DescriptionA Seton implant is usually inserted under local anesthesia, but may be done under general anesthesia for an anxious patient or child.
Since implantation may be painful for some children, drugs may be given intravenously during surgery. After anesthesia is administered, the eye is draped and retractors are placed on the eye to hold it in place.An incision is made on the conjunctiva, a thin membrane layer that lies above the sclera (white of the eye). The implant plate is placed under the conjunctiva and sutured to the sclera, carefully avoiding damage to the recti muscles in the area.
Incisions may be made in two quadrants of the eye if a double plate implant is inserted. If the tubing is implanted into the anterior chamber, that portion of the eye is drained of excess fluid. If the tube is placed in the posterior chamber of the eye, all or part of the vitreous is removed.
A needle puncture is made at the limbus where the cornea and the sclera meet, and the tubing is passed through this hole into one of the chambers of the eye. This opening is sealed with a donor scleral patch, which may be autologous (from the patient's own tissue). If a free-flow implant is used, the tubing is ligated with either a disposable suture, or the ligature is positioned such that it can be removed with a minor incision after a few weeks.
As an alternative, the non-valved implant may be inserted in two stages. The plate is first implanted, and the tube is attached during a second surgery after the bleb has formed. Diagnosis/PreparationPrior to surgery, the patient's eye is examined with a slit-lamp biomicroscope.
It is important that the conjunctiva in which the plate is placed is not scarred; that the cornea is clear; and that there are no attachments of the iris to the lens behind it or to the cornea in front of it.An ultrasound of pediatric patients is done to assess the size of the eye because not all implants are small enough to fit into a child's eye. Antibiotic drops may be given for up to three days prior to surgery. The patient will continue most glaucoma medication until the day of surgery.
Informed consent must be given for the procedure. This includes consent for surgery and a list of risks for the Seton tube implant. It is important for the patient to understand that any vision loss acquired prior to surgery cannot be corrected.
AftercareFor several weeks postoperatively, the patient is given topical antibiotics and steroids. In addition, oral steroids may be given to patients who had ocular inflammation prior to surgery. Some surgeons use atropine to maintain the eye in a temporary dilated state.
Glaucoma medication may be continued for a few months due to possible IOP fluctuation during the early post-operative period. Follow-up visits are scheduled for one day after the surgery, weekly during the first month, twice a month during the second month, and again at three months. Patients can resume normal daily activities within a few days.
The sutures may cause a foreign body sensation, which decreases as the stitches dissolve. This does not usually require treatment. Aftercare in the surgeon's office involves monitoring for the signs of hypotony and lowered IOP.
The treatment for post-operative hypotony is to tighten the tube of a non-valved implant. As the bleb forms, adjustments are made in the tubing ligature to increase flow through the ligature. If the pressure continues to rise, the tube may be blocked, and excess fluid may have to be tapped.
Tube blockage may occasionally occur. Hypotony may also be caused by leakage from the conjunctival wound site. RisksThis surgery has intraoperative and postoperative risks.
During the procedure, an extraocular muscle can be severed. This is particularly true if the implant is placed in the inferior nasal section of the eye. Strabismus and double vision may follow.
Also, the cornea may become scarred, hemorrhaging can occur within the eye, and the iris and lens can be damaged by the protruding tube. Early post-operative complications include hyphema (blood clots in the anterior chamber of the eye), hypotony, tube obstruction, suture rupture with wound leakage, movement of the implanted plate, corneal edema, and detachment of the retina. Because of the position of the implant plate, retinal detachments are difficult to treat successfully if a Seton implant is present.
Double vision during the early post-operative period may be due to swelling in the area, and often will resolve as the orbital edema decreases. Sources: http://www.answers.com/topic/tube-shunt-surgery?cat=health .
It's a plastic tube that shunts fluid from the inside of the eye to a plate that keeps the body's tissues from scarring. A complication is the drop in IOP that accompanies the Ahmed after it is implanted. The Ahmed has a valve that is variably successful in preventing hypotony.
The other shunts do not have a valve; the surgeon uses a dissolvable suture to tie off the tube leading from the eye. Sources: wills-glaucoma.org/supportgroup/20020710... .
1 You may want to clarify what type of Shunt you are referring to. (eg. Portal-caval shunt to bypass the Liver, or V-P shunt to treat hydrocephalus aka "water on the brain") .
You may want to clarify what type of Shunt you are referring to. (eg. Portal-caval shunt to bypass the Liver, or V-P shunt to treat hydrocephalus aka "water on the brain").
2 Thank you yes, V-P shunt to treat hydrocephalus.
Thank you yes, V-P shunt to treat hydrocephalus.
3 My daughter had a shunt placed four years ago following brain surgery. The experience might be hard to compare because she was also dealing with the recovery from brain surgery. The shunt is still in place and while the doctors all say that it has stopped working after all this time, she says that from time to time she can still hear it "click" on.
Her one issue is that the type she had installed is adjusted with a magnet from the outside of her skin, that means that every time she has an MRI (and she has many), she had to have it reset and not all radiology clinics have the tool to do that. If I can answer any more questions let me know.
My daughter had a shunt placed four years ago following brain surgery. The experience might be hard to compare because she was also dealing with the recovery from brain surgery. The shunt is still in place and while the doctors all say that it has stopped working after all this time, she says that from time to time she can still hear it "click" on.
Her one issue is that the type she had installed is adjusted with a magnet from the outside of her skin, that means that every time she has an MRI (and she has many), she had to have it reset and not all radiology clinics have the tool to do that. If I can answer any more questions let me know.
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I am thinking about lap band surgery. Can anyone that has had this surgery let me know their personal experience with it.
I just had arthrosocpic surgery on my knee 3/13/11. My knee still hurts like how it did before surgery not because of it.
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