Evaluation of urinary bladder function after acute spinal cord injury: an experimental study

Abstract

Objectives: The aim of this study was to evaluate the efficacy of early surgical decompression of acute spinal cord injury through the evaluation of urinary bladder function in rabbits. Materials and methods: The study was done with 21 New Zealand male rabbits which were 9 to 12 months in age, and weighed an average of 2438 grams (range 2150 to 3550 g). The animals were assigned into four groups as follows: a control group (n=5), a laminectomy group (n=6), a 15-second compression group (n=5) and a 60-second compression group (n=5). A 60 gram compression force was applied on both compression groups with aneurysm clips. All rabbits were sacrificed seven days postoperatively. Urinary bladder tissues were dissected and in vitro relaxation and contraction tests were performed in organ baths. Results: At the beginning of each experiment, 80 mM KCl was added to the isolated organ bath with no significant difference among all four groups (p>0.05). Carbachol was then added to the organ bath and contraction responses were obtained. Carbachol contraction responses were calculated as the percentage of the 80 mM KCl contraction responses, with compression groups showing significant difference from control and sham-operated groups (p<0.05). Electrical field stimulation responses were obtained for all group preparations at 4, 8, 16,32 Hz frequencies, and showed significant difference in the 15 and 60-second compression groups (p<0.05). The contractility was assessed using E-max and pD2 values. All groups exhibited same pD2 values. Conclusion: The study demonstrated a slightly better outcome for bladder contractility with early decompression. However, there was no significant difference between early and delayed decompression groups.