- Email: [email protected]
April Consultation # 9
CONSULTATION SECTION
unsightly up-drawn pupil, and the tugging on the iris could lead to cystoid macula edema. What will one encounter at surgery, and how does one repair it? In most such cases, the unwanted fistula is caused by a phaco burn, the repair of which can be difficult. I advise first placing a temporal paracentesis and putting an OVD in the anterior chamber before opening the conjunctiva because otherwise, the chamber likely will collapse when the bleb is entered. A fornix-based conjunctival flap is then raised to expose the scleral tunnel site. A cyclodialysis spatula may then be passed into the anterior chamber through the paracentesis and used to tug the iris free from the wound. Sometimes the iris will be encased in scar tissue and a small iridectomy will be required to free it. Attention is then turned to closing the scleral defect. Here is an important pearl. It defies the intuitive analysis of the problem. The closure of a leaking tunnel incision, which is a horizontal wound by definition, differs considerably from the closure of a vertical wound. What is required is to bring together the top and bottom of the tunnel and not to sew together the anterior and posterior edges of the external tunnel mouth, as one might think. This concept first occurred to me when called into the operating room to offer help to a surgeon in closing a phaco-burned temporal corneal incision. The anterior chamber was flat and the external wound had a 2.0 mm gape. His attempts to force the wound closed by placing radial sutures at the external wound entry had failed. Fortunately, it occurred to me that all that was needed was a single 10-0 nylon horizontal suture placed well out into the cornea, approximately 1.0 mm behind the internal mouth of the wound, passed deeper than the tunnel. After the suture was placed, the anterior chamber was reformed through the paracentesis and there was no leak. The external mouth of the wound continued to gape 2.0 mm. Over the next 2 weeks, the corneal stromal contraction caused by the phaco wound reversed and the wound mouth had no gape. The horizontal suture had cured the problem without creating astigmatism or, worse, claw tears and further leaks from overly tight sutures, and without requiring patch material. This same strategy should also work for a scleral tunnel phaco burn if the phaco burn does not extend all the way into the anterior chamber, in which case patching material is needed. In cases requiring patch material, I place a scleral patch or a half-thickness glycerin-preserved cornea patch (about 3.0 mm 2.0 mm) over the external opening, suspended by a horizontal mattress suture that is anchored to each side of the patch. The horizontal mattress suture provides uniform compression of the patch over the defect and avoids the use of up to 8 interrupted sutures that might be needed to achieve watertight closure. I believe that it is
554
unwise to place sutures in the defect because they usually tear through postoperatively if tight enough to close the defect; in addition, they create a great deal of astigmatism. Then, the OVD is rinsed from the anterior chamber through the paracentesis, the repair site is rechecked for leaks, and the conjunctiva is closed. Paul Palmberg, MD Miami, Florida, USA
- Inadvertent bleb formation after cataract surgery has become a less common problem over the past 2 decades as clear corneal temporal phacoemulsification has become the preferred method of cataract extraction. In this patient, in whom a superior approach was used to remove the lens, the 2 characteristics that deserve special consideration are that the patient is symptomatic and the bleb has been present for several months. If the patient were asymptomatic, the appropriate recommendation would be to do nothing given that the IOP of 7 mm Hg is acceptable. On the other hand, if a bleb were noted just a few days or weeks after the cataract surgery, the risk of going back to fix the problem (ie, future IOP elevation) would be minimal. After 6 months, however, there is a significant possibility that closing the fistula will result in prolonged and perhaps permanent IOP elevation requiring therapy. The reason for this is not completely understood, but it has been postulated that channeling aqueous humor into a bleb may cause physiologic changes in the previously normal trabecular meshwork that may result in decreased outflow facility. This hypothesis has been used to explain why IOP can dramatically increase to very high levels when a cyclodialysis cleft closes. Thus, the choice of what to do in this patient is by no means clear. The patient must weigh the possibility of tolerating bleb-related side effects with the risk for IOP elevation with bleb closure. One must also keep in mind that these blebs are not always easy to close, especially if epithelial tissue is embedded in the wound. The patient should also be made aware that bleb-related symptoms may spontaneously heal, even many months and years after surgery. That the iris is up-drawn into the cataract incision is of little consequence when making a decision on whether to intervene. The patient has excellent visual acuity in the left eye that is not being affected in any significant way by the eccentric pupil. If one were to intervene in an effort to close the incision, however, it would be reasonable to try to sweep or remove iris tissue from the wound. The decision of what to do, as in all such cases, will be made by the patient after the risks and benefits of the alternatives have been discussed. If the patient insists on the physician making the decision and acknowledges that the
J CATARACT REFRACT SURG - VOL 32, APRIL 2006
CONSULTATION SECTION
symptoms are not so severe that something must be done, I would take a conservative approach and perhaps recommend holding off any intervention for at least another 6 months. In the interim, artificial tears may be helpful in providing some symptomatic relief. If the IOP were to decline further and affect visual acuity or a bleb leak develops, I would act urgently to close the wound. Kuldev Singh, MD, MPH Stanford, California, USA
- As stated in the case report, the symptoms include ‘‘a chronic and bothersome foreign-body sensation.’’ The reason is the raised filtering bleb. If glare resulting from the pupil distortion is not a symptom, one would have to make sure the bleb alone is the symptom by trying to eliminate the sensation with a topical anesthetic agent. Another
possibility is to try a large diameter (17.0 mm) soft contact lens. If the patient reports relief with these, the raised bleb is the problem. To permanently eliminate the raised bleb, one could try to scar it with silver nitrate. If surgical repair is needed, one must consider that if the conjunctiva is sacrificed at the time of removal, amniotic membrane may be needed to cover the defect. The sclera may have to be excised, so donor tissue must also be available. One may need to release the iris from the wound to prevent reformation of the filter; I doubt the pupil will go back to a round configuration due to the time interval of 6 months. The patient must be warned of the possible complications including astigmatism, hemorrhage, endophthalmitis, epithelial downgrowth, and reformation of the bleb.
J CATARACT REFRACT SURG - VOL 32, APRIL 2006
Eduardo Alfonso, MD Miami, Florida, USA
555
unsightly up-drawn pupil, and the tugging on the iris could lead to cystoid macula edema. What will one encounter at surgery, and how does one repair it? In most such cases, the unwanted fistula is caused by a phaco burn, the repair of which can be difficult. I advise first placing a temporal paracentesis and putting an OVD in the anterior chamber before opening the conjunctiva because otherwise, the chamber likely will collapse when the bleb is entered. A fornix-based conjunctival flap is then raised to expose the scleral tunnel site. A cyclodialysis spatula may then be passed into the anterior chamber through the paracentesis and used to tug the iris free from the wound. Sometimes the iris will be encased in scar tissue and a small iridectomy will be required to free it. Attention is then turned to closing the scleral defect. Here is an important pearl. It defies the intuitive analysis of the problem. The closure of a leaking tunnel incision, which is a horizontal wound by definition, differs considerably from the closure of a vertical wound. What is required is to bring together the top and bottom of the tunnel and not to sew together the anterior and posterior edges of the external tunnel mouth, as one might think. This concept first occurred to me when called into the operating room to offer help to a surgeon in closing a phaco-burned temporal corneal incision. The anterior chamber was flat and the external wound had a 2.0 mm gape. His attempts to force the wound closed by placing radial sutures at the external wound entry had failed. Fortunately, it occurred to me that all that was needed was a single 10-0 nylon horizontal suture placed well out into the cornea, approximately 1.0 mm behind the internal mouth of the wound, passed deeper than the tunnel. After the suture was placed, the anterior chamber was reformed through the paracentesis and there was no leak. The external mouth of the wound continued to gape 2.0 mm. Over the next 2 weeks, the corneal stromal contraction caused by the phaco wound reversed and the wound mouth had no gape. The horizontal suture had cured the problem without creating astigmatism or, worse, claw tears and further leaks from overly tight sutures, and without requiring patch material. This same strategy should also work for a scleral tunnel phaco burn if the phaco burn does not extend all the way into the anterior chamber, in which case patching material is needed. In cases requiring patch material, I place a scleral patch or a half-thickness glycerin-preserved cornea patch (about 3.0 mm 2.0 mm) over the external opening, suspended by a horizontal mattress suture that is anchored to each side of the patch. The horizontal mattress suture provides uniform compression of the patch over the defect and avoids the use of up to 8 interrupted sutures that might be needed to achieve watertight closure. I believe that it is
554
unwise to place sutures in the defect because they usually tear through postoperatively if tight enough to close the defect; in addition, they create a great deal of astigmatism. Then, the OVD is rinsed from the anterior chamber through the paracentesis, the repair site is rechecked for leaks, and the conjunctiva is closed. Paul Palmberg, MD Miami, Florida, USA
- Inadvertent bleb formation after cataract surgery has become a less common problem over the past 2 decades as clear corneal temporal phacoemulsification has become the preferred method of cataract extraction. In this patient, in whom a superior approach was used to remove the lens, the 2 characteristics that deserve special consideration are that the patient is symptomatic and the bleb has been present for several months. If the patient were asymptomatic, the appropriate recommendation would be to do nothing given that the IOP of 7 mm Hg is acceptable. On the other hand, if a bleb were noted just a few days or weeks after the cataract surgery, the risk of going back to fix the problem (ie, future IOP elevation) would be minimal. After 6 months, however, there is a significant possibility that closing the fistula will result in prolonged and perhaps permanent IOP elevation requiring therapy. The reason for this is not completely understood, but it has been postulated that channeling aqueous humor into a bleb may cause physiologic changes in the previously normal trabecular meshwork that may result in decreased outflow facility. This hypothesis has been used to explain why IOP can dramatically increase to very high levels when a cyclodialysis cleft closes. Thus, the choice of what to do in this patient is by no means clear. The patient must weigh the possibility of tolerating bleb-related side effects with the risk for IOP elevation with bleb closure. One must also keep in mind that these blebs are not always easy to close, especially if epithelial tissue is embedded in the wound. The patient should also be made aware that bleb-related symptoms may spontaneously heal, even many months and years after surgery. That the iris is up-drawn into the cataract incision is of little consequence when making a decision on whether to intervene. The patient has excellent visual acuity in the left eye that is not being affected in any significant way by the eccentric pupil. If one were to intervene in an effort to close the incision, however, it would be reasonable to try to sweep or remove iris tissue from the wound. The decision of what to do, as in all such cases, will be made by the patient after the risks and benefits of the alternatives have been discussed. If the patient insists on the physician making the decision and acknowledges that the
J CATARACT REFRACT SURG - VOL 32, APRIL 2006
CONSULTATION SECTION
symptoms are not so severe that something must be done, I would take a conservative approach and perhaps recommend holding off any intervention for at least another 6 months. In the interim, artificial tears may be helpful in providing some symptomatic relief. If the IOP were to decline further and affect visual acuity or a bleb leak develops, I would act urgently to close the wound. Kuldev Singh, MD, MPH Stanford, California, USA
- As stated in the case report, the symptoms include ‘‘a chronic and bothersome foreign-body sensation.’’ The reason is the raised filtering bleb. If glare resulting from the pupil distortion is not a symptom, one would have to make sure the bleb alone is the symptom by trying to eliminate the sensation with a topical anesthetic agent. Another
possibility is to try a large diameter (17.0 mm) soft contact lens. If the patient reports relief with these, the raised bleb is the problem. To permanently eliminate the raised bleb, one could try to scar it with silver nitrate. If surgical repair is needed, one must consider that if the conjunctiva is sacrificed at the time of removal, amniotic membrane may be needed to cover the defect. The sclera may have to be excised, so donor tissue must also be available. One may need to release the iris from the wound to prevent reformation of the filter; I doubt the pupil will go back to a round configuration due to the time interval of 6 months. The patient must be warned of the possible complications including astigmatism, hemorrhage, endophthalmitis, epithelial downgrowth, and reformation of the bleb.
J CATARACT REFRACT SURG - VOL 32, APRIL 2006
Eduardo Alfonso, MD Miami, Florida, USA
555