Tuesday, September 29, 2009

trabectome

Last Wednesday Ava had a surgical consultation at Children's with Dr. M, for her glaucoma *1. This was actually our second surgery consultation, the first one was about 8 months ago at University of Chicago. That doctor didn't think surgery was necessary at this time, or possibly ever. Since that appointment there had been other changes in her eye pressures and eye structures, so our doctor (Dr. K) referred us for another opinion. He just didn't feel comfortable sitting around waiting for her optic nerve to be damaged. Her pressures had remained stable the last 3 months while we were waiting to get in for our consultation so at our last office visit our doctor actually said he was expecting the surgeon to say she was fine and wouldn't need surgery, but he just wanted to hear it from another surgeon because it just wasn't sitting right with him.

If you have ever had to do the whole consultation with any type of well known doctor, you know how much hassle it is to just go to the appointment. Knowing that Dr. K was expecting Dr. M to pass on surgery made the whole thing seem kind of pointless. I felt like we were driving in traffic for 2 hours, to wait about 3 hours for about 15 minutes of face time with all the different personnel, to then drive another hour plus home, just to check it off our list, to say that yep, another doctor said no. I was a little surprised after Dr. M turned the lights back on and said, "Based on what I see, and the increased cupping of her left eye, I would definitely treat her with surgery. Her pressures aren't really controlled with medication and her nerves won't withstand these pressures." Well that wasn't what we had been expecting. She went on to say that she wants to do a total of 4 surgeries if everything goes well.

Here is the basics of the surgery:

"Trabectome® is a minimally invasive procedure specifically designed to improve fluid drainage from the eye to balance intraocular pressure (IOP). By restoring the eye’s natural fluid balance, the Trabectome procedure stabilizes optic nerve health to minimize further visual field damage.

The surgery is performed through a small incision and does not require leaving a permanent hole in the eye wall or creation of an external filtering bleb (fluid collection on the outside of the eye) or an implant.

Following are steps for the Trabectome procedure:

1. A small (1/16 of an inch) incision is made on the affected eye.
2. A small strip of diseased tissue is removed with an electrosurgical pulse to open access to the drainage system of the eye.
3. The eye is irrigated with a saline solution to remove tissue debris, leaving the eye to recover almost immediately.

Trabectome is an out-patient surgery that allows the patient to go home the same day. It is particularly offered to patients who are allergic to medications or who prefer to use surgical interventions instead of other medical therapies. The Trabectome procedure is performed on glaucoma patients at many leading ophthalmic centers."

This may bring up the question of why Dr. K sent us to another surgeon. He is one of the leading pediatric ophthalmologists in the area. Based on where we live, that actually says something vs. leading in the three surrounding counties total population 200. Ava doesn't just have pediatric glaucoma. She has sturge weber type glaucoma which is a whole different scenario. Part of if it, they don't actually know what causes is it. Because they aren't sure what the cause is, it makes it harder to treat. They are just treating the symptoms. Because she had the port wine birthmark on both lids of her right eye and the bottom of her left, it was pretty much a done deal that she would have glaucoma in her right and about a 70% chance that she would have it in her left. She has the extra blood vessels that make up the birthmark on the sclara and the retna of her eye. This can cause major complications during surgery, mainly bleeding. This surgery isn't any more life threatening than any of the other times she goes under general anesthesia, so that isn't a real concern for us since she does it all the time. The risk with bleeding in the eye is that the retna can seperate, there can be swelling of the optic nerve that can cause damage and permanent vision loss. As with any surgery there is a risk of infection, so she will have to wear an eye patch for at least a little bit. Other risks could be that the pressure drops too much and her eye collapses. (ewwwww!) This surgery is has around a 70-90% success rate in normal glaucoma patients. It is really hard to find rates in sturge weber glaucoma patients because it is just not a type of research that is funded.

So the possible benefits of this surgery are: drop the pressures down to a normal level so that we can take her off at least some, if not all of the medication she is on for at least some time. We will probably have to do more surgeries in the future, so this is definitely not a permanent cure, but buying us time is always a good thing. The older she gets, the more medications become available. We scheduled the surgery for the Tuesday before Halloween. It is only a 15 minute surgery, so I have been told, so at least we will get to go home that morning. We will have to go back the next day to have things checked out but I heard those appointments are around lunch time so at least we won't be driving in traffic 2 days in a row. That is all I know for now. Hopefully this post has answered questions instead of confusing you all more. Go study the anatomy of the eye. It is really a complex piece of machinery.


*1 Glaucoma is a chronic, life long disease of the eye which results in an increased inner ocular pressure (IOP)(pressure in her eye). This pressure causes the eye to sometimes expand, causing clouding of the cornea and the optic nerve to elongate and seperate. Ava regularly has her pressures checked (normal range us less than 10 in adults, in children they try to get under 15. Ava's are currently ranging between 20 and 30). Her axial length (length of eye, front to back), diameter of the cornea, and the cupping of her optic nerve, the cup to disc ratio (c/d). Normal eyes have a c/d ratio of 0 to .3. Ava's c/d ratio had always been around .1 or .2, and it has recently gone up to .4. This is an important number because the cupping ratio means that there is damage to the optic nerve. The more it cups, the more the nerve fibers separate with a complete separation at a 1.0. The vision loss occurs from the outside in, as the nerve separates. Right now Ava has 20/20 vision so we have no knowledge of any vision loss, which is the over all goal, to keep her from losing any of her sight.



This is the picture of normal cupping (.3)



This is how they measure. It is broken down into 10 sections and counted off.