Trabeculectomy
for Glaucoma
To the Editor.\p=m-\Inthe August issue of the Archives (92:134, 1974), Schwartz and Anderson presented the results
of trabeculectomies performed for different types of glaucoma. I wish to disagree with the statement that "the precise location of the excision of the trabecular meshwork and Schlemm's canal may not be necessary." Excising sclera over the ciliary body behind the insertion of the iris root is ineffective, since the ciliary body blocks the newly created escape route. On the other hand, excising corneal tissue anterior to the Schwalbe line can lead to corneal edema and refractive complications. For this reason, the only site left for excision is the filtration area. The authors fail to mention the extent and thickness of tissue excised. If the increase of resistance to out\x=req-\ flow is based on a sclerosing process involving not only the trabecular meshwork but possibly the overlying sclera, enough tissue in length and depth must be removed to permit adequate filtration to occur. It has been my experience that at least a 7 mm long strip is necessary for this. In ad¬ dition, if only a thin scleral flap was left, my results were better than with a thicker one. Complications can be reduced by meticulous microsurgical techniques. The area to be excised is outlined with a razor blade, lifted with a mos¬ quito forceps, and dissected out with¬ out entering the anterior chamber. I never use scissors since the inner blade would have to be inserted under the strip into the anterior chamber. In my hands, trabeculectomies give the best results of filtering operations with the least complications. Marcel
Back, MD
Spring Valley, NY Reply.\p=m-\Weappreciate Dr Back's interest in our article. His letter raises two points. The first is in regard to the need to localize exactly the Schlemm canal and the trabecular meshwork. Our point was that since a trabeculectomy works by filtration and not by having aqueous pass through the cut ends of the Schlemm canal, it is not necessary to have the Schlemm canal in the excisional space. However, we agree with Dr Back that one should be in In
the general area of the filtration meshwork. If one's dissection is too far toward the posterior side, the ciliary body may be encountered with bleeding, vitreous loss, or an inad-
vertent
cyclodialysis as complications.
If it is too far anteriorly, corneal problems may develop. In response to his second point, our usual scleral flap is about 5 mm \m=x\5 mm and the tissue excised is usually a 1 mm\m=x\4mm strip. This size has been adequate in our hands. The other very important variable besides the extent and thickness of the tissue excised is the tightness of the closure of the scleral flap. We suspect that many of these variables are interdependent. Thus, with one type of suture and a certain size flap, optimum success is achieved with a certain size of excised tissue and a certain tightness of clo¬ sure. Requirements for optimum suc¬ cess might be different with a differ¬ ent suture and a different size scleral
flap.
We hope that this helps clarify the issues raised. We are glad that Dr Back joins us in favoring the trabeculectomy as the primary choice of fil¬
tering
surgery. Arthur L.
Schwartz, MD Washington, DC Douglas R.
Miami, Fla
Anderson, MD
Temporal Arteritis and Pulmonary Emboli To the Editor.\p=m-\Iam presently prea paper on giant cell arteritis and read with interest an article by Stanley A. Uriu, MD, and Robert D. Reinecke, MD, in the November 1973 issue of the Archives titled "Temporal arteritis, steroid therapy, and pulmonary emboli" (90:355, 1973). These authors suggested that the treatment of this disease with high dose steroids may have a relationship to the pulmonary emboli supposedly verified in these cases. I cannot refute their theory, but I would like to suggest that these two patients may have had a vasculitis of the pulmonary arteries causing these symptoms, which are identical to pulmonary emboli seen in patients with
paring
systemic lupus erythematosus (SLE). I have recently observed such a case. I was initially quite confident with results of lung scans and clinical laboratory evidence that the patient indeed had multiple recurrent pulmonary emboli. She had been receiving anticoagulation therapy, as had the
Downloaded From: http://archopht.jamanetwork.com/ by a UQ Library User on 06/21/2015
patients in this article, but because of recurrent chest pain, pleurisy, and pleural friction rubs, the patient fi¬ nally had a catheterization to the right side of the heart that revealed no evidence of pulmonary emboli, even though chest roentgenogram and lung scan were abnormal at this
time. These episodes of supposed pulmo¬ nary emboli are quite common in pa¬ tients with SLE and I suggest that the same cause could be proposed for giant cell arteritis. My point is that patients with this disease who are go¬ ing to be receiving anticoagulants may suffer dire consequences of the anticoagulation therapy, especially if given in conjunction with high dose steroid therapy. Pulmonary angiograms might be indicated to verify the suspected pulmonary emboli. Dale C. Brentlinger, MD, FACP Denver
Reply.\p=m-\Clinicalmanifestations of pulmonary vasculitis and emboli are rarely, if ever, seen in patients with temporal arteritis. In fact, our search In
of the literature uncovered no such relationship. On occasion, however, pulmonary arteritis has been reported in the larger autopsy series. There are increasing reports in the literature of vasculopathy in patients with temporal arteritis affecting major vessels other than the temporal artery, such as the major branches of the aorta. It is well known that patients with systemic lupus erythematosus often develop vasculitis that will affect any vessel. Thus, it would appear not unusual that Dr Brentlinger's patient was demonstrated to have pulmonary vasculitis. I agree with Dr Brentlinger that pulmonary vasculitis may explain the episodes of supposed pulmonary emboli in our patients. I would think that embolization would be the more occurrence. Unfortunately, pulmonary arteriography was not done on our patients. However, our patients have done reasonably well with the combination therapy of anti\x=req-\ coagulants and high doses of steroids on an alternate day schedule. common
I have made no mention of the role of steroids in this discussion. Is it causally related to thromboemboli phenomena? Only further study can answer that. Stanley A. Uriu, MD Robert D. Reinecke, MD Albany, NY
for Glaucoma
To the Editor.\p=m-\Inthe August issue of the Archives (92:134, 1974), Schwartz and Anderson presented the results
of trabeculectomies performed for different types of glaucoma. I wish to disagree with the statement that "the precise location of the excision of the trabecular meshwork and Schlemm's canal may not be necessary." Excising sclera over the ciliary body behind the insertion of the iris root is ineffective, since the ciliary body blocks the newly created escape route. On the other hand, excising corneal tissue anterior to the Schwalbe line can lead to corneal edema and refractive complications. For this reason, the only site left for excision is the filtration area. The authors fail to mention the extent and thickness of tissue excised. If the increase of resistance to out\x=req-\ flow is based on a sclerosing process involving not only the trabecular meshwork but possibly the overlying sclera, enough tissue in length and depth must be removed to permit adequate filtration to occur. It has been my experience that at least a 7 mm long strip is necessary for this. In ad¬ dition, if only a thin scleral flap was left, my results were better than with a thicker one. Complications can be reduced by meticulous microsurgical techniques. The area to be excised is outlined with a razor blade, lifted with a mos¬ quito forceps, and dissected out with¬ out entering the anterior chamber. I never use scissors since the inner blade would have to be inserted under the strip into the anterior chamber. In my hands, trabeculectomies give the best results of filtering operations with the least complications. Marcel
Back, MD
Spring Valley, NY Reply.\p=m-\Weappreciate Dr Back's interest in our article. His letter raises two points. The first is in regard to the need to localize exactly the Schlemm canal and the trabecular meshwork. Our point was that since a trabeculectomy works by filtration and not by having aqueous pass through the cut ends of the Schlemm canal, it is not necessary to have the Schlemm canal in the excisional space. However, we agree with Dr Back that one should be in In
the general area of the filtration meshwork. If one's dissection is too far toward the posterior side, the ciliary body may be encountered with bleeding, vitreous loss, or an inad-
vertent
cyclodialysis as complications.
If it is too far anteriorly, corneal problems may develop. In response to his second point, our usual scleral flap is about 5 mm \m=x\5 mm and the tissue excised is usually a 1 mm\m=x\4mm strip. This size has been adequate in our hands. The other very important variable besides the extent and thickness of the tissue excised is the tightness of the closure of the scleral flap. We suspect that many of these variables are interdependent. Thus, with one type of suture and a certain size flap, optimum success is achieved with a certain size of excised tissue and a certain tightness of clo¬ sure. Requirements for optimum suc¬ cess might be different with a differ¬ ent suture and a different size scleral
flap.
We hope that this helps clarify the issues raised. We are glad that Dr Back joins us in favoring the trabeculectomy as the primary choice of fil¬
tering
surgery. Arthur L.
Schwartz, MD Washington, DC Douglas R.
Miami, Fla
Anderson, MD
Temporal Arteritis and Pulmonary Emboli To the Editor.\p=m-\Iam presently prea paper on giant cell arteritis and read with interest an article by Stanley A. Uriu, MD, and Robert D. Reinecke, MD, in the November 1973 issue of the Archives titled "Temporal arteritis, steroid therapy, and pulmonary emboli" (90:355, 1973). These authors suggested that the treatment of this disease with high dose steroids may have a relationship to the pulmonary emboli supposedly verified in these cases. I cannot refute their theory, but I would like to suggest that these two patients may have had a vasculitis of the pulmonary arteries causing these symptoms, which are identical to pulmonary emboli seen in patients with
paring
systemic lupus erythematosus (SLE). I have recently observed such a case. I was initially quite confident with results of lung scans and clinical laboratory evidence that the patient indeed had multiple recurrent pulmonary emboli. She had been receiving anticoagulation therapy, as had the
Downloaded From: http://archopht.jamanetwork.com/ by a UQ Library User on 06/21/2015
patients in this article, but because of recurrent chest pain, pleurisy, and pleural friction rubs, the patient fi¬ nally had a catheterization to the right side of the heart that revealed no evidence of pulmonary emboli, even though chest roentgenogram and lung scan were abnormal at this
time. These episodes of supposed pulmo¬ nary emboli are quite common in pa¬ tients with SLE and I suggest that the same cause could be proposed for giant cell arteritis. My point is that patients with this disease who are go¬ ing to be receiving anticoagulants may suffer dire consequences of the anticoagulation therapy, especially if given in conjunction with high dose steroid therapy. Pulmonary angiograms might be indicated to verify the suspected pulmonary emboli. Dale C. Brentlinger, MD, FACP Denver
Reply.\p=m-\Clinicalmanifestations of pulmonary vasculitis and emboli are rarely, if ever, seen in patients with temporal arteritis. In fact, our search In
of the literature uncovered no such relationship. On occasion, however, pulmonary arteritis has been reported in the larger autopsy series. There are increasing reports in the literature of vasculopathy in patients with temporal arteritis affecting major vessels other than the temporal artery, such as the major branches of the aorta. It is well known that patients with systemic lupus erythematosus often develop vasculitis that will affect any vessel. Thus, it would appear not unusual that Dr Brentlinger's patient was demonstrated to have pulmonary vasculitis. I agree with Dr Brentlinger that pulmonary vasculitis may explain the episodes of supposed pulmonary emboli in our patients. I would think that embolization would be the more occurrence. Unfortunately, pulmonary arteriography was not done on our patients. However, our patients have done reasonably well with the combination therapy of anti\x=req-\ coagulants and high doses of steroids on an alternate day schedule. common
I have made no mention of the role of steroids in this discussion. Is it causally related to thromboemboli phenomena? Only further study can answer that. Stanley A. Uriu, MD Robert D. Reinecke, MD Albany, NY
