The authors demonstrate a reproducible technique using processed pericardium to seal sclerostomy track during glaucoma shunt revision. The suggested method involves placement of a wedge-shaped processed pericardial graft into the old sclerostomy tract following tube explantation. The graft is trimmed and sutured to the sclera. The tube is reinserted into a new sclerostomy and then sutured in place and covered in the usual fashion. This method allowed relatively easy treatment of three patients with patulous sclerostomy with necrotic edges. A successful tube revision and repositioning of the tube using this technique was performed on three patients with exposed tubes. The intraocular pressure was between 8 and 12 mm Hg from postoperative day 1. The authors suggest the use of pericardium plug to adequately seal the old sclerostomy track during glaucoma shunt revision. The plug allows tube repositioning at a new site without the need to suture the friable sclerostomy edges.
From the Department of Ophthalmology (TAS), Massachusetts Eye and Ear Infirmary/Harvard Medical School, Boston, Massachusetts; Assiut University Hospital (TAS), Department of Ophthalmology, Assiut, Egypt; and Reading Health Center (MAL), Reading, Massachusetts.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Mark A. Latina, MD, 20 Pond Meadow Dr., Ste. 203, Reading, MA 01867. E-mail: firstname.lastname@example.org
Received: December 23, 2010
Accepted: September 23, 2011
Posted Online: October 27, 2011
Erosion of the silicone tube through the overlying conjunctiva is one of the most common complications following aqueous shunt implantation.1 It may be associated with uveitis, scleritis, scleral necrosis, and epithelization of the sclerostomy tract with tube hypermobility and leakage.
Simple repair of the conjunctival defect in such cases may not be sufficient. Explantation of the tube and re-implantation in an adjacent area or complete explantation of the whole device may be necessary.
Sealing the old sclerostomy using simple suturing may not be successful due to the friability of the scleral edges. Inadequate closure of the old sclerostomy may lead to excessive aqueous leakage and hypotony following the tube revision. On the other hand, using tight stitches may lead to excessive surgically induced astigmatism and poor visual outcome.
We demonstrate a new surgical technique using processed pericardium to plug the patulous sclerostomy track. The plug will effectively seal the sclerostomy track with minimal stress.
Following proper retrobulbar block and appropriate surgical draping, a 6-0 Vicryl suture on S-29 spatulated needle (Ethicon, Inc., Cornelia, GA) is applied to the inferior limbus to act as a bridle suture. The conjunctiva is incised around the exposed tube and mobilized on each side of the tube. The fibrous track and any epithelium growing underneath the tube are excised (Fig. 1). Wet field bipolar electrocautery is used to secure hemostasis.
Figure 1. Initial debridement. (A) Preoperative photograph showing the exposed juxta-limbal part of the tube (short arrow). (B) Following conjunctival dissection, a fibrous track and epithelial down growth and scleral necrosis and leakage around the tube can be visualized (long arrow).
Preparation of the Pericardial Scleral Plug
With the aid of the surgical microscope, commercially available processed pericardium (Tutoplast; New World Medical, Inc., Rancho Cucamonga; or IOP, Inc., Costa Mesa, CA) is cut to fashion a wedge-shaped plug. First, a 1.5 × 6 mm strip is cut from the dry graft using Westcott sharp tenotomy scissors (Stephens Instruments, Lexington, KY). Then, one end is cut so that it has a slanting end (Fig. 2). The pericardial graft and the instruments should be perfectly dry during the pericardial plug preparation.
Figure 2. Preparation of the pericardial scleral plug. The dry processed pericardium patch (A) is cut at the dotted line using sharp Westcott tenotomy scissors to excise a 1.5 × 6 mm strip. The pericardial strip (B) is then cut at the dotted line to produce a wedge-shaped graft with a pointed end (C).
Insertion and Suturing of the Pericardial Scleral Plug
The tube is explanted from the existing sclerostomy track. The pointed end of the pericardial plug is then inserted into the sclerostomy track (Fig. 3) using KT5-2500 Castroviejo 0.12 forceps (Katena Products, Inc., Denville, NJ). The plug is further advanced using a K3-2310 fine Barraquer spatula (Katena Products, Inc.) until it can be just visualized in the anterior chamber. As the pericardium is hydrated by the aqueous, it seals the fistula. The exposed part of the plug is then trimmed so that the part projecting outside the sclerostomy is 2 to 3 mm long. This part is then sutured to the sclera with two mattress stitches using 10-0 nylon sutures on a TG160-4 spatulated needle (Ethicon, Inc.).
Figure 3. Insertion and suturing of the pericardial scleral plug. (A) The tube is explanted from the leaky sclerostomy track. (B) The pointed end of the plug is then inserted through the sclerostomy track. (C) The plug is further advanced using fine Barraquer spatula until it can be just visualized in the anterior chamber. The plug is then trimmed so that the part projecting outside the sclerostomy is 2 to 3 mm long. (D) This part is sutured to the sclera with two mattress stitches using 10-0 nylon sutures.
Reinsertion, Suturing, and Coverage of the Tube
A new sclerostomy site is created on either side of the old plugged sclerostomy using a 23-gauge needle approximately 0.5 mm posterior to the limbus, parallel or angling slightly forward to the iris plane. The tube is reinserted into the anterior chamber through the new sclerostomy. The tube is sutured in place using 10-0 nylon sutures. The tube and the plugged sclerostomy are then covered with a processed pericardial graft. The conjunctiva is sutured back in place using 10-0 nylon sutures in the usual fashion (Fig. 4).
Figure 4. Reinsertion, suturing, and coverage of the tube. (A) A new sclerostomy site on either side of the old plugged sclerostomy is created using a 23-gauge needle. (B) The tube is reinserted into the anterior chamber through the new sclerostomy and sutured in place using 10-0 nylon sutures. (C) The tube and the plugged sclerostomy are then covered with a processed pericardial graft. (D) The conjunctiva is then sutured back in place using 10-0 nylon sutures.
A successful tube revision and repositioning of the tube using the processed pericardial plug was performed on three patients with exposed tubes. The intraocular pressure was between 8 and 12 mm Hg from postoperative day 1, and was well controlled without any glaucoma medications during the 12-month follow-up period. The tubes were in good position with adequate conjunctival coverage at subsequent follow-up visits. Tube exposure did not recur in any of the patients who underwent this procedure.
Until fairly recently, tube shunts were considered a “surgical last resort” in patients who had a failed prior trabeculectomy. Recently, this has changed and tube shunt surgery is becoming more popular. For some surgeons, glaucoma shunt surgery is even becoming the primary glaucoma surgery of choice.2
The Tube Versus Trabeculectomy study demonstrated that tube shunt surgery was more likely to maintain intraocular pressure control at 1 year, and indicated that a trabeculectomy was more than four times as likely to fail at 1 year.2 The study also showed that there were more postoperative complications in the trabeculectomy group (57% in the trabeculectomy group and 34% in the tube group).3
With the increased popularity of tube shunt surgery as a primary surgical option, an increase in the incidence of shunt-related long-term postoperative complications is to be expected. Erosion of the silicone tube through the overlying conjunctiva is one of the most common complications following aqueous shunt implantation.3 It may be associated with chronic uveitis, scleritis, scleral necrosis, and epithelial down growth into the sclerostomy tract with tube hypermobility and leakage.
Such a challenging situation can be managed with proper debridement of the perilimbal area with proper mobilization and explantation of the tube. Plugging the old sclerostomy with a processed pericardial graft has the advantages of minimizing the suture stress on the friable edges of the sclera and the surgically induced astigmatism.
We suggest the use of a pericardium plug to adequately seal the old sclerostomy track during glaucoma shunt revision. The plug stops aqueous leakage from the sclerostomy site and allows tube repositioning at a new site without the need to suture the friable sclerostomy edges.
- Gedde SJ, Schiffman JC, Feuer WJ, et al. Treatment outcomes in the Tube Versus Trabeculectomy study after one year of follow-up. Am J Ophthalmol. 2007;143:9–22. doi:10.1016/j.ajo.2006.07.020 [CrossRef]
- Mosaed S, Minckler DS. Aqueous shunts in the treatment of glaucoma. Expert Rev Med Devices. 2010;7:661–666. doi:10.1586/erd.10.32 [CrossRef]
- Gedde SJ, Herndon LW, Brandt JD, Budenz DL, Feuer WJ, Schiffman JC. Surgical complications in the Tube Versus Trabeculectomy study during the first year of follow-up. Am J Ophthalmol. 2007;143:23–31. doi:10.1016/j.ajo.2006.07.022 [CrossRef]