When used with a non-penetrating deep sclerectomy procedure, the AquaFlow™ collagen glaucoma implant has been proven to significantly lower intraocular pressure while minimizing both the complications often associated with penetrating procedures and reducing the need for medications. As a result, open-angle glaucoma patient outcomes are predictable and patient follow-up is more easily managed.
The term “non-penetrating” refers to procedures that do not penetrate the anterior chamber of the eye. A very thin yet durable membrane is left intact, allowing for the controlled flow of eye fluid out of the anterior chamber. An additional source of improved flow of fluid is through the angle where outflow normally occurs. During the AquaFlow glaucoma implant procedure, the tissue that most greatly impedes outflow of fluid through the angle is stripped away in a simple maneuver. This allows for two avenues of increased fluid release, but in a controlled and gradual amount.
This controlled approach prevents intraocular pressure reduction exceeding safe limits to maintain a healthy eye. The five-year follow-up data on 105 patients 1, 2 shows a desirable pattern of IOP with a good initial pressure drop and well maintained pressures long term. With a reduction rate of more than 60 percent, the result of the controlled approach is much greater than drops and/or laser therapy can achieve.
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Once the outflow of fluid is established through a non-penetrating deep sclerectomy, the challenge is to maintain a channel for the fluid to follow to access the normal vascular system. Normal body tissues that have been separated will scar together during the natural body healing process. The AquaFlow collagen glaucoma implant, which measures .5 mm in width by 4mm in length, swells in width to more than twice the original size as it absorbs eye fluid.
One of the most impressive features of this device is that it takes approximately six to nine months to dissolve. The normal time for the eye to continue to scar/heal the surgical site is less than the life of the device. Once the AquaFlow glaucoma implant has dissolved, a channel remains to allow for the eye fluid to move to the desired locations and maintain the lower eye pressure. No other material to date has shown the ability to prevent deep scarring, reduce intraocular pressure, and maintain the outflow of fluid while disappearing at the appropriate stage of healing. Learn even more by reviewing some of the professional publications written on the AquaFlow open angle glaucoma procedure, or by contacting STAAR® Surgical Company today.
Performing a non-penetrating deep sclerectomy in conjunction with the AquaFlow collagen glaucoma implant has shown significantly lower postoperative complications 3 when compared to the trabeculectomy. Lower rates of complications can mean improved outcomes and comfort for the patient following surgery, as well as greater overall satisfaction.
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Because the surgeon does not have to enter the anterior chamber, there is a reduced rate of cataract formation related to the surgical procedure. Many patients that benefit from the reduced intraocular pressure with AquaFlow are advancing in years and will therefore naturally develop cataracts; however, the overall percentage of AquaFlow patients who develop cataracts is much less than with trabeculectomy.
Both surgical procedures reduce the number of topical medications needed to control intraocular pressure at lower levels. It is interesting to note that, following the AquaFlow procedure, there is less need for supplemental medications to reduce pressures than with trabeculectomy.
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Early ultrasound biomicroscopy (UBM) studies confirm that the AquaFlow collagen device is maintained in the deep scleral space for six to nine months.
Ultrasound Biomicroscopy Sequence
1 Month Post-Op
3 Month Post-Op
6 Month Post-Op
The ultrasound biomicroscopy sequence of images reveals the dissolving and reabsorbing pattern of the AquaFlow collagen device. It is evident that the device prevents fibrosis and maintains an egress pathway for aqueous.
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The AquaFlow open-angle glaucoma procedure involves creating a superficial flap of scleral tissue to cover and hold the AquaFlow collagen glaucoma implant in place. A second deeper flap is dissected at a specific depth to maintain a thin barrier of natural eye tissues. This allows the aqueous fluid to begin to exit the eye at an increased but controlled rate.
The aqueous outflow is enhanced by stripping or removing the inner lining of Schlemm’s canal. This tissue is the site of greatest resistance to aqueous outflow through the trabecular meshwork.
The collagen AquaFlow device is sutured into position to maintain a space between the upper scleral flap and the base tissues. The collagen swells to more than twice the size in a dry state to prevent normal tissue healing and scarring, which would slow or stop the aqueous outflow.
The superficial flap is loosely closed over the collagen device to allow for the aqueous fluid to flow from underneath the flap to a space between the conjunctiva (clear outer eye covering) and top of the scleral flap. This fluid space is termed a “bleb” and allows the aqueous to be absorbed into the small blood vessel present in this region.
The arrows illustrate the various aqueous outflow mechanisms that produce the desired lower eye pressures. Early studies suggest an increased formation of deep tissue collector channels surrounding the site where the collagen is located. This mechanism may enhance the long-term results for intraocular pressure reduction.
Over the next six to nine months the AquaFlow collagen glaucoma implant gradually dissolves. This extended amount of time is necessary to allow the natural healing mechanisms of the eye to subside.
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Following are a number of common questions received by AquaFlow proctors. If you have a question or concern regarding the glaucoma implant that is not covered here, please contact STAAR Surgical Company today.
A: Clinical trials comparing Non-penetrating Deep Sclerectomy (NPDS) with AquaFlow collagen glaucoma implant to standard trabeculectomy revealed similar intraocular pressure reduction with significantly less postoperative complications. This easier post-op course of treatment may require less office visits.
A: The procedure was approved for patients with open-angle glaucoma (Grade 3 or 4), although some surgeons are expanding to narrower angles with good outcomes by use of iridoplasty or laser iridotomy.
A: The following open-angle glaucoma patients would be excellent candidates for NPDS with the AquaFlow collagen glaucoma implant:
A: Most surgeons that perform trabeculectomy have the majority of the instruments needed; however, there are several instruments unique to the AquaFlow glaucoma implant that can enhance the outcomes of the procedure:
A: STAAR Surgical Company AquaFlow proctors are available to bring training to you. With a commitment of a minimum of three AquaFlow cases, a proctor can schedule a time to arrive the evening prior to surgery and provide the didactic and wet lab in your facility. You can then transfer those acquired skills to your surgical patients the next day.
A: To ensure optimal patient outcomes, STAAR Surgical Company requires that a surgeon is proctored for their initial AquaFlow case(s) to provide the recommended steps of the procedure and methods. Once the surgeon and proctor feel that a comfort level is achieved, STAAR Surgical Company will place the surgeon's name on the "Approved" list for orders and a listing on the AquaFlow surgeon locator website if desired. Also offered is a full certification course with Dr. Thomas W. Samuelson, Course Director of the Phillips Eye Institute in Minneapolis, Minnesota.
A: Patients with an angle narrower than Grades 3 or 4 open-angle glaucoma are at the greatest risk of iris incarceration; patients who also have a darker pigmented iris are at an even higher risk. Some surgeons have experienced good outcomes with narrower angles with the pre-treatment of an iridoplasty or iridotomy, which can expand the range of patient candidates.
A: Reports from surgeons indicate the use of 5-fluorouracil and mitomycin C to inhibit fibrosis in the episceral area for some of the higher risk patients. As with trabeculectomy, the use of antimetabolites would be considered an off-label application of the collagen glaucoma implant.
A: Frequently, corticosteriods and antibiotics are prescribed after AquaFlow open-angle glaucoma surgery. Cycloplegics and miotics tend to be prescribed less frequently.
A: This is probably due to a lack of depth of the surgical dissection. Once the dissection is taken fully to Descemet's membrane, adequate flow will result. An option exists to perform an Nd: YAG goniopuncture, aiming the beam at the trabeculo-descemet's membrane on either side of the AquaFlow anterior in the window as far as possible. The use of a magnifying gonioscopy lens aids in visualizing the site.
A: The normal non-penetrating open-angle glaucoma procedure can continue if the size of the perforation is estimated to be less than 1.5mm. A valuable step in the procedure is to decompress the anterior chamber with a parasentesis as soon as Schlemm's canal is located and prior to creating a Descemet's window. This intraocular pressure reduction often avoids a macro-perforation caused by the iris being pushed through the opening by higher pressures. When positioning the AquaFlow glaucoma implant in these cases, the device should be positioned over the micro-perforation and used as a tampanade to control the flow.
A: In order to minimize bleeding and enhance visualization, if possible discontinue the following medications prior to the glaucoma implant surgery:
A: The most common challenges with this glaucoma implant procedure that STAAR Surgical Company has been made aware of are either not initiating the deep flap at the proper depth of 90 percent or starting at 90 percent depth but end up at 70 percent depth and missing Schlemm's canal. The solution is to go posterior and begin a deeper dissection in order to "de-roof" Schlemm's canal.
A: 1) Small Descemet's window (Less than 1.5mm from anterior to posterior)
2) Superficial window dissection (Mid Stromal Descemet's window)
3) Failure to adequately remove the juxtacanalicular tissue (Floor of Schlemm's canal)
A: Yes, the combined procedure can be performed at the same surgical site or two separate sites. The early recovery of visual acuity with NPDS results in an improved outcome in this area compared to cataract surgery combined with a trabeculectomy.
A: This glaucoma implant procedure is most often billed as a trabeculectomy (CPT 66170) or an Aqueous Shunt (CPT 66180). As with all procedures, you will establish your Usual and Customary (U&C) fee for the particular procedure code. Private pay patients will pay your U&C fee with third party payers reimbursing at their established rates. Please see the AquaFlow Monograph for current Medicare rates for the procedure.
If you have any further questions or concerns about the AquaFlow collagen glaucoma implant and its use in relieving intraocular pressure for open-angle glaucoma cases please contact STAAR Surgical Company, or search the company's collection of professional publications.
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Led by Thomas W. Samuelson, MD, Course Director of the Phillips Eye Institute in Minneapolis, Minnesota, this full certification course will give participants in-depth instruction on the innovative AquaFlow glaucoma implant procedure. The Minneapolis, one-day course will provide participants with the following:
The $995.00 tuition will also include a hotel room for the previous Sunday evening in Minneapolis, and continental breakfast and lunch served during the day of the course. Please inform us of any dietary restrictions.
Proposed course dates for 2007: To Be Announced. For further information, please contact Sherryl Joos at 1-952-903-9522.
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To learn more about the intraocular pressure relief provided during open-angle glaucoma surgery using AquaFlow, the collagen glaucoma implant, contact STAAR Surgical Company today.
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1. Deep Sclerectomy with Collagen implant: medium term results. Br J Ophthalmology 1999 Jan; 83 (1): 6-11. Karlen ME, Sanchez E, Schnyder CC, Sickenberg M, Mermoud A.
2. Deep sclerectomy with collagen implant. Presented at UC Irvine, Jan. 8, 2000.
3. Comparison of deep sclerectomy with collagen implant and trabeculectomy in open-angle glaucoma. J Cataract Refract Surg 1999 Mar; 25(3): 323-31. Mermoud A, Schnyder CC, Sickenber M, Chiou AG, Hediguer SE, Faggioni R.