Análise da vascularização do testículo abdominal em fetos humanos: bases anatômicas para a Cirurgia de Fowler-Stephens

Abstract

High abdominal testis with short gonadal vessels in patients with cryptorchidism is a challenging condition. Fowler-Stephens surgery is the procedure of choice in these cases. There are studies about performing this procedure in 1 or 2 stages, and knowledge of the testicle’s vascularization is a key factor to perform this procedure. Studies on the vascularization of abdominal testicles are rare and histological studies on abdominal testicular vascularization are nonexistent in the literature. The objective of this study was to determine the percentage of area occupied by vessels of the upper and lower portions of human fetal testicles. 34 testicles from 19 human fetuses aged 12 to 19 weeks post conception (WPC) (mean 15 WPC) were studied. The fetuses were macroscopically well preserved, with no abnormalities of the urinary and genital systems. The testes were dissected and processed for paraffin embedding. Sections of 5 µm with intervals of 15 µm were made. The sections were stained by Masson's Trichrome and marked with CD31 antibody for vessel identification and quantification. Images were obtained with an Olympus BX51 microscope and Olympus DP70 camera attached. Area density measurement was done using the ImageJ program and 100-point grid plugin. A line was drawn approximately in the median portion dividing the testis into upper and lower portion. Statistical analysis was done using the GraphPad Prism program. The unpaired Student's t-test was used to compare the vessel area density of the upper and lower testicles. Linear regression analysis was also performed using the variables fetal weight, fetal age with right and left testis and upper and lower portion of testis. Fetal weight ranged from 58g to 551g with a mean of 222.5g; total length between 11cm and 56.5cm with a mean of 23.2cm; vertex coccyx length between 8cm and 25cm with a mean of 15.3cm. Considering all 34 testicles, we observed the mean number of vessels in the upper portion was 7.6% with maximum 15% and minimum 4.6%. In the lower portion 5.11%, maximum 9.8%, minimum 2.3%, p = 0.0001. We did not observe any difference between the right and left testicle regarding the vascularized area during the studied period. The upper portion of the testicle showed higher density of area occupied by vessels blood when compared to the lower portion. The linear regression analysis did not show statistical significance. These results confirmed the importance of performing a minimum manipulation of the lower extremity of the testicle during Fowler-Stephens surgery.