Investigation of the effect of dorsal penile block to penile tissue

Abstract

Background Dorsal penile block (DPB) is a frequently used technique for regional anesthesia, but the effect of DPB on penile tissue has not been reported so far. Objective An experimental study was conducted to evaluate the acute effects of DPB on penile tissue. Methods Eighteen male rats were included and randomly assigned to three groups. No intervention was made in the control group (CG, n = 6). In the sham group (SG, n = 6) 1 ml normal saline, and in DPB group (PBG, n = 6) 1 ml of 0.25% bupivacaine without adrenaline (0.5 mg/kg), was infused with a 30 mm, 23 gauge needle. DPB was performed by inserting the needle in the midline when pulling down the penis and directing the needle to the 11 and 1 o'clock positions. Another puncture was done at the midline on the ventral side and the remaining drug was infused slowly. The penile tissues were harvested for biochemical (malonyldialdehyde: MDA; nitric oxide: NO; superoxide dismutase: SOD) and histopathological examination. Histopathological assessments were made of inflammation, edema and fibrosis; epithelial degradation in the urethra; vascular obliteration in periurethral tissue; and the peripheral nerve cells. Results Concentrations of NO and SOD were significantly decreased in the PBG compared with the CG and SG (p < 0.05). The concentration of MDA was significantly increased in the PBG compared with the CG and SG (p < 0.05) (Table). Histopathological examination revealed no significant difference between groups regarding edema, inflammation, or fibrosis (p > 0.05). In hematoxylin and eosin stain samples, vascular structures of the corpus cavernosa were slightly decreased in number in the SG and PBG compared with the CG, but that difference was not statistically significant (p > 0.05). The S100 staining was significantly higher in the PBG and SG compared with the CG (p < 0.05), and significantly higher in the SG compared with the PBG (p < 0.05). Discussion DPB causes alteration in oxidative stress markers because of an unknown effect. Although the results revealed increased inflammatory reaction in penile tissue after DPB, they are not enough to suggest not using bupivacaine for DPB in clinical practice. Conclusion Although DPB does not cause any major histopathological alteration, it results in an increase in inflammatory response in the penile tissue in the short term.