Intraprostatic ethanol diffusion: comparison of two injection methods using ex vivo human prostates

BACKGROUND: Intraprostatic injection of ethanol has been previously tested in clinical trials as a potential treatment of BPH, with variable outcomes. As evident from animal studies, the inconsistency was owing to various degrees of ethanol backflow along the needle tract. In acute canine experiments, we previously documented that using convection enhanced delivery (CED) eliminates backflow and improves ethanol distribution. The goal of this study was to compare the diffusion pattern between a microporous hollow fiber catheter (MiHFC) and a standard needle in human prostates from organ donors.

METHODS: Prostates were harvested from cadaveric organ donors immediately after removal of organs for transplant. After trimming off excess fat and weighing, prostates were injected with absolute ethanol. The total injected volume was 25% of the calculated prostate volume. One lateral lobe was injected using a single lumen 21-gauge control needle. The contralateral lobe was injected with the same volume but using a MiHFC. Immediately after injection, prostates were fixed en bloc in 10% neutral-buffered formalin, and then sectioned. Three-dimensional reconstruction was performed to determine lesion volume based on hematoxylin- and eosin-stained cross-sections.

RESULTS: Three fresh human prostates were harvested and injected. The time from harvest to intraprostatic injection was 15-35 min. The lesion created by the MiHFC was 1.14±0.52 cm(3), whereas that from the control needle was 0.28±0.10 cm(3) (P=0.038). No backflow was observed along the needle tract of the MiHFC.

CONCLUSIONS: This study shows that freshly harvested human prostates can be used to evaluate new treatments using intraprostatic injection. Similar to in vivo canine experiments, the ethanol lesion sizes were significantly bigger with the use of a MiHFC when compared with a standard single lumen needle.