Changes of testicular blood flow after vasectomy: Assessment by color Doppler ultrasound resistive index measurement

Objective: The objectives of this study were to evaluate the testicular blood flow in patients after vasectomy by use of color Doppler ultrasound resistive index measurement.

Patients, subjects and methods: The study included 50 healthy men scheduled for vasectomy. Patients were assessed before and 3 and 6 months after surgery. Both testes were examined using color Doppler ultrasound with a linear array 15MHz transducer (Acuson, Sequoia). The Resistive Index (RI) of the testicular artery were measured at two locations: at the convoluted aspect (spermatic cord) and intratesticular (close to the rete testis). Additionally the volume of the testicles was determined.

Results: All measures were obtainable. The mean volume of the testes was 17.5±5.7 mL before and 19.7±7.1 mL after vasectomy. RI ranged from 0.45 to 0.67. Measures for left and right testes were similar (P>0.10). The majority of the measures showed higher RI values at the cord location than intratesticular (P<0.05).

The overall increase of intratesticular RI was significant (P<0.05) and ranged from 0.51±0.09 (before vasectomy) to 0.59±0.08 (3 months after vasectomy). The RI returned to basic values at the 6 month control (mean RI: 0.52±0.07).

Conclusions: The RI is a reliable indicator for routine clinical use to evaluate the testicular blood flow. The significant increase after vasectomy may indicate a slightly decreased perfusion of the testicles due to swelling based on a transitory disturbance of lymph drainage. Further investigation will show the utility of RI measurements in estimation of testicular function.