Comparison between the conventional and a modified Morgan “pocket technique” for the treatment of prolapsed nictitans gland (“cherry eye”) in dogs.
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PURPOSE. The aim of this study was to determine whether a modified surgical technique for nictitans gland prolapse (NGP) correction resulted in a significant decreased number of NGP reoccurrences, as compared to the number of reoccurrences after the ”regular” Morgan pocket technique. Furthermore, we aimed to find out if other factors concerning the ocular condition or the surgery, such as additional eye disease or the surgeon’s experience, influenced the number of reoccurrences. METHODS. A total of 157 dogs with unilateral or bilateral hyperplasia of the gland of the nictitating membrane participated in this study, consisting of thirty-nine different dog(cross)breeds. The total number of eyes that were diagnosed and operated on was 256. All eyes were treated surgically prior to this study, either by using the regular Morgan pocket technique (n=125) or using the modified pocket technique (n=131) in the period from March 1994 until April 2010 at ‘Het Medisch Centrum voor Dieren’ in Amsterdam or at the ‘University Clinic for Companion Animals’ in Utrecht. All owners with dogs were asked by telephone to participate in this study. If they were willing to participate, a questionnaire was verbally conducted through the telephone. The data collected from the questionnaires was statistically analyzed with the Chi-square test and the Likelihood Ratio test to determine a possible significant difference in reoccurrence between the two surgical techniques and to asses if certain variables could possibly influence the rate of reoccurrence. RESULTS. The surgical technique used to correct NGP was in 48.8% (n=125) cases the “regular” Morgan pocket technique and in 51.2% (n=131) cases the modified pocket technique. The Morgan pocket technique had nineteen (=15.2%) reoccurrences and the modified pocket technique had fifteen reoccurrences (=11.5%). Of the 256 eyes that were diagnosed with NGP and were operated on, 19.1% had additional eye problems like kerato-conjunctivitis sicca (7%), macroblepharon (2%), tear quality problems (0.8%) or follicular conjunctivitis (0.8%). 12.9% had ‘other’ eye problems like entropion, trichiasis, distichiasis or ectropion. There were six different veterinary eye specialists or residents that operated the dogs with NGP in this study. Their experience (in days) was calculated for each particular NGP surgery. The average number of days of experience for NGP that had a reoccurrence is 4449.9 with a standard deviation of 4482.8 days (minimum=90 days and maximum=12317 days). The average number of days of experience for NGP that did not have a recurrence is 4726.0 with standard deviation of 4312.2 days (minimum=90 days and maximum=11204 days). After the dogs had undergone NGP surgery, 90.5% of the dog owners were satisfied about the results, 3.8% were dissatisfied and 5.7% did not give a conclusive answer. CONCLUSIONS. Results demonstrated no significant difference in the rate of reoccurrence between the two surgical techniques (p-value=0.377). Furthermore, the statistical analysis concluded that surgical experience of the veterinary ophthalmologist did not have an effect on the reoccurrence of NGP. This study did show that there is a link between the number of reoccurrences and the presence of additional eye disease.