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Inflow of ocular surface fluid through clear corneal cataract incisions: A laboratory model
Treatment and Long-term Outcome of Patients With Orbital Cavernomas EDITOR:
4. Shields JA, Shields CL, Eagle RC Jr. Transconjunctival approach for orbital tumors [in reply]. Arch Ophthalmol 1988;106:14 –15. 5. Gdal-On M, Gelfand YA. Tc-99m RBC scintigraphy of orbital cavernous hemangioma. Eur J Ophthalmol 1999;9:125–129.
WE ARE SURPRISED THAT SCHEUERLE AND ASSOCIATES1
are using the frontotemporal approach for the removal of cavernous hemangiomas. Since our report2 in 1985, we have been treating such patients almost exclusively by transconjunctival cryoextraction. In 1993 Loewenstein and associates3 reported 33 of our cases, including 2 in detail (not 1, as stated in Table 4), and have now operated on over 50 cavernomas by this approach. Shields and associates4 agreed that most of these tumors can be removed transconjunctivally. The authors concede that “especially small orbital cavernomas located laterally or medially to the eyeball can be excised by a transconjunctival approach.” However, our experience2,3 has shown that the larger the tumor, the more accessible its anterior edge, making it easier to visualize and reach with the cryoprobe. Because of the compressibility of the cavernomas, we are able to remove them in their entirety without regard to their position. Only the rare small cavernoma in the apex of the orbit will not be reachable by this method. In addition, we don’t understand the authors’ attempt to minimize the significance of their severe complications, including subdural hematoma, reduced visual acuity, and loss of visual field in nearly 30% of their patients. We reported no serious complications in 33 patients using the transconjunctival approach.3 Our excellent experience continues to this day. With ultrasound, computed tomography, magnetic resonance imaging, and red blood cell scintigraphy,5 cavernous hemangiomas can be diagnosed preoperatively, reached by a transconjunctival approach, and removed safely and completely by cryosurgery with good cosmetic results and without complication. A transcranial approach with its reported morbidity should not be considered except in rare cases. M. LAZAR, MD L. ROTHKOFF, MD J. P. DREY, MD
Tel Aviv, Israel
AUTHOR REPLY LAZAR QUOTES FROM OUR ARTICLE A VARIETY OF SEVERE
complications after the transcranial approach. To preclude other readers from misunderstanding, we confirm that two of 14 patients suffered severe visual loss. One of these 2 patients also had a third-nerve paresis. Both patients initially presented with headaches and significantly impaired preoperative visual acuity due to extended compression of the optic nerve in the orbital apex. We therefore suggested immediate surgical excision of the orbital cavernomas producing the visual deficits. Another patient who was operated on by a maxillofacial surgeon developed a postoperative subdural hematoma and retained a frontal lobe syndrome. We reported this case for the very reason that a transcranial approach should be considered only by surgeons experienced in the management of the specific, possibly severe complications. Furthermore, our intention was to point out that the decision to intervene surgically has to be made with extreme caution. Besides the loss of visual acuity, muscle palsy, and permanent diplopia, a severe impairment of visual function must be considered and may follow any kind of orbital surgery. Invasive therapy should be chosen only in the presence of symptoms clearly attributable to the lesion; therefore, careful ophthalmologic examination and follow-up are always mandatory. In the literature the transconjuctival removal of large orbital tumors is reported only occasionally. Our group has no experience with cryosurgery of orbital cavernomas, but we are intrigued that the transconjunctival extraction of large orbital cavernomas using a cryoprobe is so safe that they can be removed without regard to their position. Trauma to cranial nerves by traction or compression seems to be eliminated with the transconjunctival cryoextraction. A search of MEDLINE reveals that not many other surgical centers have been able to share and to publish the advantages of this technique. ALEXANDER F. SCHEUERLE
Heidelberg, Germany
REFERENCES
1. Scheuerle AF, Steiner HH, Kolling G, Aschoff A. Treatment and long-term outcome of patients with orbital cavernomas. Am J Opthalmol 2004;138:237–244. 2. Lazar M, Rosen N, Geyer O. A transconjunctival cryosurgical approach for intraorbital tumors. Aust. N Z J Ophthalmology 1985;13:417– 420. 3. Loewenstein A, Geyer O, Lazar M. Cavernous hemangioma of the orbit: treatment by transconjunctival cryoextraction. Eye 1993;7:597–598.
VOL. 139, NO. 4
Inflow of Ocular Surface Fluid Through Clear Corneal Cataract Incisions: A Laboratory Model AN UNSUTURED CLEAR CORNEAL INCISION FOR PHACO-
emulsification is currently de rigueur, despite the fact that temporal clear corneal incisions have been shown to increase the endophthalmitis rate.1,2 In the study by
CORRESPONDENCE
753
Cooper and associates,3 cataract surgery using corneal incisions carried a higher risk of endophthalmitis (odds ratio, 3.36) compared with scleral incisions. Surprisingly, subgroup analysis showed that sutures made no difference in the risk of endophthalmitis, although the numbers were small. There has been some suggestion in the literature that the incidence of endophthalmitis may be increasing.2 From hospital coding data, the number of endophthalmitis admissions to hospitals in New South Wales, Australia, from July 1994 to June 2003 was 3,171 cases; over the same period, the number of cataract operations performed in New South Wales was 380,362 cases, giving an incidence of 1 in 120 (0.83%). This is an overestimate of the rate, because it includes endogenous endophthalmitis, and the cases have not been verified, but the rate is significantly higher than previously reported. We therefore applaud the report by Sarayba5 and associates, which is particularly relevant in the context of a possibly rising rate of endophthalmitis. A key factor may be the use of an unsutured temporal clear corneal incision.1–3 Shingleton and associates4 showed that intraocular pressure (IOP) can be low in the early postoperative period, and Sarayba and associates, in a forthcoming manuscript in Ophthalmology, report corneal wound gape with low IOP. These articles provide a mechanism to explain Sarayba and associates’ demonstration of fluid inflow at low IOPs in a laboratory model. These studies suggest that surgical patients are susceptible to endophthalmitis by opening a channel along which organisms may enter the eye. Sarayba and associates showed that applying external pressure to one quadrant of the cornea to raise the pressure of the eye by 10 to 20 mm Hg causes inflow. The distortion of the globe may directly cause wound gape, allowing fluid inflow into the eye. The physiologic equivalent of this may be rubbing of an eye, which may distort a wound in a similar way to allow inflow of fluid. In Sarayba and associates’ study, there was only one eye sutured to act as a control. Given that only four of the seven experimental eyes demonstrated leakage, it would be difficult to draw a conclusion regarding the effectiveness of suturing to prevent postoperative leakage due to fluctuations in IOP or manual pressure on the globe. However, we hypothesize that a sutured wound should maintain the anatomic apposition of the wound edges in the face of a reduction in IOP or manual pressure applied to the globe. The clinical significance of Sarayba and associates’ work needs to be established by prospective studies of endophthalmitis in relation to wound site and suturing in clear corneal incisions. What is important in the meantime is that surgeons consider the best wound construction and instruct patients carefully on postoperative care, including avoidance of eye rubbing and early presentation should vision loss or pain develop postoperatively. 754
AMERICAN JOURNAL
DEREK G. CHAN, MBBS IAN C. FRANCIS, FASOPRS JOHN A. DOWNIE, FRANZCO
Sydney, Australia
REFERENCES
1. Nagaki Y, Hayasaka S, Kadoi C, et al. Bacterial endophthalmitis after small-incision cataract surgery. Effect of incision placement and intraocular lens type. J Cataract Refract Surg 2003;29:20 –26. 2. Lertsumitkul S, Myers PC, O’Rourke MT, Chandra J. Endophthalmitis in the western Sydney region: a case-control study. Clin Experiment Ophthalmol 2001;29:400 – 405. 3. Cooper BA, Holekamp NM, Bohigian G, Thompson PA. Case-control study of endophthalmitis after cataract surgery comparing scleral tunnel and clear corneal wounds. Am J Ophthalmol 2003;136:300 –305. 4. Shingleton BJ, Wadhwani RA, O’Donoghue MW, et al. Evaluation of intraocular pressure in the immediate period after phacoemulsification. J Cataract Refract Surg 2001;27: 524 –527. 5. Sarayaba MA, Taban M, Ignacio TS, Behrens A, McDonnell PJ. Inflow of ocular fluid through clear corneal cataract incisions: a laboratory model. Am J Ophthalmol 2004;138: 206 –210.
AUTHOR REPLY WE THANK DR. CHAN AND COWORKERS FOR THEIR LETTER.
The endophthalmitis data they report are certainly of concern. However, as they clearly state in their communication, all cases detected in their search cannot be solely attributed to postoperative cataract surgery. We encourage Dr. Chan’s group to present detailed data on postoperative endophthalmitis in New South Wales, Australia, because these results may corroborate a similar trend reported in other parts of the world. Chan and associates highlight the effect of the increased intraocular pressure (IOP) induced by external maneuvers as a possible risk factor for changes on the corneal wound architecture of cataract incisions. In addition to that, we observed in our model that the inflow of India ink occurred immediately after the external manual pressure was released, possibly when the IOP tends to decrease abruptly. This mechanism may be responsible for the inflow of extraocular fluid, whereas the higher IOP could explain the opposite event: intraocular fluid leakage. Chan and associates also comment on the variability observed in our results, in which some of the experimental eyes under the same conditions of stress did not show India ink inflow. This may reflect the fact that some eyes have particular resistance to the inflow by mechanisms not detected in our model, that there are subtleties of wound construction that may not be recognized or that all corneas do not have the same biomechanical properties. In addiOF
OPHTHALMOLOGY
APRIL 2005
4. Shields JA, Shields CL, Eagle RC Jr. Transconjunctival approach for orbital tumors [in reply]. Arch Ophthalmol 1988;106:14 –15. 5. Gdal-On M, Gelfand YA. Tc-99m RBC scintigraphy of orbital cavernous hemangioma. Eur J Ophthalmol 1999;9:125–129.
WE ARE SURPRISED THAT SCHEUERLE AND ASSOCIATES1
are using the frontotemporal approach for the removal of cavernous hemangiomas. Since our report2 in 1985, we have been treating such patients almost exclusively by transconjunctival cryoextraction. In 1993 Loewenstein and associates3 reported 33 of our cases, including 2 in detail (not 1, as stated in Table 4), and have now operated on over 50 cavernomas by this approach. Shields and associates4 agreed that most of these tumors can be removed transconjunctivally. The authors concede that “especially small orbital cavernomas located laterally or medially to the eyeball can be excised by a transconjunctival approach.” However, our experience2,3 has shown that the larger the tumor, the more accessible its anterior edge, making it easier to visualize and reach with the cryoprobe. Because of the compressibility of the cavernomas, we are able to remove them in their entirety without regard to their position. Only the rare small cavernoma in the apex of the orbit will not be reachable by this method. In addition, we don’t understand the authors’ attempt to minimize the significance of their severe complications, including subdural hematoma, reduced visual acuity, and loss of visual field in nearly 30% of their patients. We reported no serious complications in 33 patients using the transconjunctival approach.3 Our excellent experience continues to this day. With ultrasound, computed tomography, magnetic resonance imaging, and red blood cell scintigraphy,5 cavernous hemangiomas can be diagnosed preoperatively, reached by a transconjunctival approach, and removed safely and completely by cryosurgery with good cosmetic results and without complication. A transcranial approach with its reported morbidity should not be considered except in rare cases. M. LAZAR, MD L. ROTHKOFF, MD J. P. DREY, MD
Tel Aviv, Israel
AUTHOR REPLY LAZAR QUOTES FROM OUR ARTICLE A VARIETY OF SEVERE
complications after the transcranial approach. To preclude other readers from misunderstanding, we confirm that two of 14 patients suffered severe visual loss. One of these 2 patients also had a third-nerve paresis. Both patients initially presented with headaches and significantly impaired preoperative visual acuity due to extended compression of the optic nerve in the orbital apex. We therefore suggested immediate surgical excision of the orbital cavernomas producing the visual deficits. Another patient who was operated on by a maxillofacial surgeon developed a postoperative subdural hematoma and retained a frontal lobe syndrome. We reported this case for the very reason that a transcranial approach should be considered only by surgeons experienced in the management of the specific, possibly severe complications. Furthermore, our intention was to point out that the decision to intervene surgically has to be made with extreme caution. Besides the loss of visual acuity, muscle palsy, and permanent diplopia, a severe impairment of visual function must be considered and may follow any kind of orbital surgery. Invasive therapy should be chosen only in the presence of symptoms clearly attributable to the lesion; therefore, careful ophthalmologic examination and follow-up are always mandatory. In the literature the transconjuctival removal of large orbital tumors is reported only occasionally. Our group has no experience with cryosurgery of orbital cavernomas, but we are intrigued that the transconjunctival extraction of large orbital cavernomas using a cryoprobe is so safe that they can be removed without regard to their position. Trauma to cranial nerves by traction or compression seems to be eliminated with the transconjunctival cryoextraction. A search of MEDLINE reveals that not many other surgical centers have been able to share and to publish the advantages of this technique. ALEXANDER F. SCHEUERLE
Heidelberg, Germany
REFERENCES
1. Scheuerle AF, Steiner HH, Kolling G, Aschoff A. Treatment and long-term outcome of patients with orbital cavernomas. Am J Opthalmol 2004;138:237–244. 2. Lazar M, Rosen N, Geyer O. A transconjunctival cryosurgical approach for intraorbital tumors. Aust. N Z J Ophthalmology 1985;13:417– 420. 3. Loewenstein A, Geyer O, Lazar M. Cavernous hemangioma of the orbit: treatment by transconjunctival cryoextraction. Eye 1993;7:597–598.
VOL. 139, NO. 4
Inflow of Ocular Surface Fluid Through Clear Corneal Cataract Incisions: A Laboratory Model AN UNSUTURED CLEAR CORNEAL INCISION FOR PHACO-
emulsification is currently de rigueur, despite the fact that temporal clear corneal incisions have been shown to increase the endophthalmitis rate.1,2 In the study by
CORRESPONDENCE
753
Cooper and associates,3 cataract surgery using corneal incisions carried a higher risk of endophthalmitis (odds ratio, 3.36) compared with scleral incisions. Surprisingly, subgroup analysis showed that sutures made no difference in the risk of endophthalmitis, although the numbers were small. There has been some suggestion in the literature that the incidence of endophthalmitis may be increasing.2 From hospital coding data, the number of endophthalmitis admissions to hospitals in New South Wales, Australia, from July 1994 to June 2003 was 3,171 cases; over the same period, the number of cataract operations performed in New South Wales was 380,362 cases, giving an incidence of 1 in 120 (0.83%). This is an overestimate of the rate, because it includes endogenous endophthalmitis, and the cases have not been verified, but the rate is significantly higher than previously reported. We therefore applaud the report by Sarayba5 and associates, which is particularly relevant in the context of a possibly rising rate of endophthalmitis. A key factor may be the use of an unsutured temporal clear corneal incision.1–3 Shingleton and associates4 showed that intraocular pressure (IOP) can be low in the early postoperative period, and Sarayba and associates, in a forthcoming manuscript in Ophthalmology, report corneal wound gape with low IOP. These articles provide a mechanism to explain Sarayba and associates’ demonstration of fluid inflow at low IOPs in a laboratory model. These studies suggest that surgical patients are susceptible to endophthalmitis by opening a channel along which organisms may enter the eye. Sarayba and associates showed that applying external pressure to one quadrant of the cornea to raise the pressure of the eye by 10 to 20 mm Hg causes inflow. The distortion of the globe may directly cause wound gape, allowing fluid inflow into the eye. The physiologic equivalent of this may be rubbing of an eye, which may distort a wound in a similar way to allow inflow of fluid. In Sarayba and associates’ study, there was only one eye sutured to act as a control. Given that only four of the seven experimental eyes demonstrated leakage, it would be difficult to draw a conclusion regarding the effectiveness of suturing to prevent postoperative leakage due to fluctuations in IOP or manual pressure on the globe. However, we hypothesize that a sutured wound should maintain the anatomic apposition of the wound edges in the face of a reduction in IOP or manual pressure applied to the globe. The clinical significance of Sarayba and associates’ work needs to be established by prospective studies of endophthalmitis in relation to wound site and suturing in clear corneal incisions. What is important in the meantime is that surgeons consider the best wound construction and instruct patients carefully on postoperative care, including avoidance of eye rubbing and early presentation should vision loss or pain develop postoperatively. 754
AMERICAN JOURNAL
DEREK G. CHAN, MBBS IAN C. FRANCIS, FASOPRS JOHN A. DOWNIE, FRANZCO
Sydney, Australia
REFERENCES
1. Nagaki Y, Hayasaka S, Kadoi C, et al. Bacterial endophthalmitis after small-incision cataract surgery. Effect of incision placement and intraocular lens type. J Cataract Refract Surg 2003;29:20 –26. 2. Lertsumitkul S, Myers PC, O’Rourke MT, Chandra J. Endophthalmitis in the western Sydney region: a case-control study. Clin Experiment Ophthalmol 2001;29:400 – 405. 3. Cooper BA, Holekamp NM, Bohigian G, Thompson PA. Case-control study of endophthalmitis after cataract surgery comparing scleral tunnel and clear corneal wounds. Am J Ophthalmol 2003;136:300 –305. 4. Shingleton BJ, Wadhwani RA, O’Donoghue MW, et al. Evaluation of intraocular pressure in the immediate period after phacoemulsification. J Cataract Refract Surg 2001;27: 524 –527. 5. Sarayaba MA, Taban M, Ignacio TS, Behrens A, McDonnell PJ. Inflow of ocular fluid through clear corneal cataract incisions: a laboratory model. Am J Ophthalmol 2004;138: 206 –210.
AUTHOR REPLY WE THANK DR. CHAN AND COWORKERS FOR THEIR LETTER.
The endophthalmitis data they report are certainly of concern. However, as they clearly state in their communication, all cases detected in their search cannot be solely attributed to postoperative cataract surgery. We encourage Dr. Chan’s group to present detailed data on postoperative endophthalmitis in New South Wales, Australia, because these results may corroborate a similar trend reported in other parts of the world. Chan and associates highlight the effect of the increased intraocular pressure (IOP) induced by external maneuvers as a possible risk factor for changes on the corneal wound architecture of cataract incisions. In addition to that, we observed in our model that the inflow of India ink occurred immediately after the external manual pressure was released, possibly when the IOP tends to decrease abruptly. This mechanism may be responsible for the inflow of extraocular fluid, whereas the higher IOP could explain the opposite event: intraocular fluid leakage. Chan and associates also comment on the variability observed in our results, in which some of the experimental eyes under the same conditions of stress did not show India ink inflow. This may reflect the fact that some eyes have particular resistance to the inflow by mechanisms not detected in our model, that there are subtleties of wound construction that may not be recognized or that all corneas do not have the same biomechanical properties. In addiOF
OPHTHALMOLOGY
APRIL 2005