Dacryocystorhinostomy with intraoperative mitomycin C

Ophthalmology

Volume 105, Number 1, January 1998

that limiting mitomycin exposure to a single intraoperative application is probably safer than postoperative topical administration, although not without complications as Dr. Hardten illustrates in his case report. CURTIS A. MANNING, MD PRaCE M. KLOESS, MD

San Antonio, Texas Dacryocystorhinostomy with Intraoperative Mitomycin C Dear Editor: The report by Dr. Kao and colleagues, "Dacryocystorhinostomy with Intraoperative Mitomycin C " (Ophthalmology 1997; 104:86-91), mentions their successful experience with intraoperative mitomycin C (MMC) in external dacryocystorhinostomy (DCR). We do not see the need for MMC in an operation that is successful 90% of the time in experienced hands. We have also used intraoperative MMC in a limited number of endoscopic nonlaser-assisted DCR series. We applied a higher concentration of the drug (0.5 mg/ml) for a shorter time interval (2.5 minutes). Although we concluded that 0.5 mg/ml MMC for 2.5 minutes favorably affected wound healing in the osteotomy, ~ we did not observe a meaningful difference between the MMC and control group in terms of ostium size or success rates. The authors applied 0.2 mg/ml mitomycin C for 30 minutes, a much longer interval than we used. We wonder if there was a rationale for the duration of application or, if it was arbitrary. According to the method in the article, MMC was applied to a large area (placement of the cottonoid over the anastomozed posterior flaps and its transnasal removal). Did MMC use increase the operating time? One suggestion from this study is that a longer exposure time could produce a larger ostium, in contrast to our higher concentration-shorter application study. A rationale for the duration and method of the application should be determined. SUAT HAYRI U~URBA~, MD GOLER ZILELIO(3IU,MD

Ankara, Turkey Reference 1. U~urba§ SH, Zilelio~lu G, Sargon MF, et al. Histopathologic effects of mitomycin C on endoscopic transnasal dacryocystorhinostomy. Ophthalmic Surg Lasers 1997;28: 360-4. Author's reply Dear Editor: The success rate of external DCR is approximately 90%, but we are still making simple modifications to improve patient outcomes. As in our study, we still routinely use mitomycin C (MMC)-soaked neurosurgical cottonoids with long silk strings attached placed between the anterior and posterior flaps. We let the long silk protrude from the nasal cavity in our external DCR operation. It.takes less than 1 minute 4

to perform that procedure in the operating room. We then remove the MMC-soaked cottonoid transnasally by pulling out the long silk 30 minutes after MMC soaking outside the OR. An MMC exposure time of 30 minutes was arbitrarily chosen in our study as an interval likely to maximally inhibit fibrosis. There were no complications, such as wound disruption, flap necrosis, or bony necrosis. SHU LANG LIAO, MD, MPH

Taipei, Taiwan Optic Nerve Hypoplasia Dear Editor: In the article of Siatkowski et al, " T h e Clinical, Neuroradiographic, and Endocrinologic Profile of Patients with Bilateral Optic Nerve Hypoplasia" (Ophthahnology 1997; 104:493-6) the conclusions about the management of optic nerve hypoplasia (ONH) seem to be inappropriate due to the fact that magnetic resonance imaging (MRI) was not performed in all the patients. Indeed in 1993 Brodsky and Glasier I introduced a classification of ONH based on the results of MRI of the central nervous system (CNS), which allowed one to predict in an individual child the risk of neurodevelopmental deficit and endocrinologic deficiency. Brodsky and Glasier recommended management of children with ONH based on this classification. Although many other reports also found an important association between ONH and CNS abnormalities, Siatkowski et al do not recommend neuroimaging in ONH unless there is an additional clinical finding. The authors did not find a correlation between the results from neuroimaging and future neurologic and cognitive performance, but only 19 of 35 patients underwent MRI of the brain. Therefore the authors conclusions were independent of the results of neuroimaging. In our Department of Pediatric Ophthalmology, 52 children with ONH were examined between 1990 and 1997. Classification of 20 patients who underwent MRI of the brain revealed high predictability of the risk to develop endocrinologic deficiency? Evidence of hormone deficiency was present in all children who showed posterior pituitary ectopia or infundibular hypoplasia (group III). It is important to realize that even if there is no growth retardation, endocrine dysfunction may exist. Variable levels of glycemia probably are unfavorable for the neurodevelopment of these children. Classification, as recommended by Brodsky and Glasier, is also very useful for discussing the neurodevelopmental prognosis of a child with ONH with the parents. The children in group I neither showed neurodevelopmental deficit nor mental retardation. Children with septo-optic-dysplasia (SOD) may show developmental delay and neurologic abnormalities, e.g., seizures and hemiparesis, and children of group IV with hemispheric migration anomalies are especially at risk. Most children of group V have neurodevelopmental delay and neurologic deficit. Prenatal injury can often not be diagnosed without neuroimaging. A significant correlation between SOD and decreased maternal age (DMA < 20 y) has been reported. 2 Based on this high correlation between SOD and DMA, it has been recently suggested that SOD is the result of a vascu-