Laser Doppler spectroscopy of testes after unilateral orchiopexy

Undescended testes are the most common urogenital malformation in boys. Impaired microcirculation is among other factors addressed as a potential complication of surgery and scar formation, leading to long-term suboptimal results.

Our aim was to compare the postoperative microcirculation in operated versus non-operated contralateral testis groups after unilateral orchiopexies versus a healthy control cohort.

Ninety-nine consecutive patients were included after unilateral orchiopexy procedures at the age of 3.5 years (±2.9 years) at a single center for pediatric surgery. Eight-five patients were examined with a combination of laser Doppler (blood flow determination) and white-light spectroscopy (oxygen saturation and hemoglobin amount determinations) to determine the microcirculation at two different depth levels non-invasively. All relevant surgery data were obtained retrospectively.

The right side was operated in 53.5% of cases. Previous hormone treatment had been prescribed in 46.5%. There were no significant differences in perfusion measurements between patients with previous hormone therapy and patients without. There was no significant difference in age and clinical pubertal stage between groups; however, 65% of patients underwent surgery after their second birthday. When comparing oxygen saturation (So2), relative hemoglobin (rHb), flow, and velocity in the operated testis with the contralateral testis of the same patients, we found significantly higher flows and velocities for the contralateral testes (p = 0.041, p = 0.022). Similar higher flows and velocities were found in the healthy controls (p < 0.001). The differences between healthy controls and contralateral testis that were not operated on did not reach statistical significance. There was no difference in measurements at 2 mm depth (skin and subcutaneous tissue) between groups to rule out systemic or capillary differences.

Important limitations include the limited and relatively heterogeneous samples that were obtained for follow-up and retrospective surgery data collection. An additional limitation is missing presurgical data, which we hope to obtain in future studies. Hormonal data or bone age could not be obtained for study reasons. The age in our study was on average above the recommended age for orchiopexy in Germany (6-12 months), which could also restrict generalizability. In terms of complications, we observed reascending testes within the range but a rather high incidence of wound infections. The combination of Doppler and white-light spectroscopy was easily applicable and produced reliable data at 2 and 8 mm depth simultaneously in a standardized setting.

After orchiopexy, differences were found in the microcirculation between the operated and contralateral testes or healthy controls. It remains unclear if this is an effect of primary disease or surgery. The microcirculation of contralateral testes was also seemingly different from controls. This is most likely not a consequence of surgery alone, but a common problem for both testes in the affected patients.