Optimizing laboratory use of human vas deferens specimens for microsurgical practice.

Objectives: To determine whether freezing harvested human vas deferens would preserve the tissue for later microsurgical practice. Learning and maintaining microsurgical skills requires laboratory practice. The proper preservation of the human vas deferens is important if harvested specimens are to be used for laboratory vasovasostomy.

Methods: Segments of human vas deferens harvested at the time of radical retropubic prostatectomy were preserved at -20 degrees C without media, in normal saline and in glycerol. At 2 weeks, the specimens were thawed and graded for freshness of appearance, mucosal preservation, mucosal suturing quality, muscularis preservation, and muscularis suturing quality at laboratory vasovasostomy (grade 1, poor; 2, fair; and 3, good). Mucosa and muscularis scores were calculated as the sum of the respective preservation and suturing quality grades. The preserved samples were compared with fresh human vas deferens specimens.

Results: Freezing human vas deferens segments in normal saline or glycerol improved the mucosa and muscularis scores at 2 weeks compared with freezing tissues without media. However, a decrease in the freshness of appearance grade was noted. None of the freezing methods resulted in tissue quality as good as fresh vas deferens.

Conclusions: Human vas deferens can be preserved for later microsurgical vasovasostomy practice at -20 degrees C. Freezing in normal saline and glycerol improved the mucosa and muscularis scores compared with freezing without media, although a decrease in the freshness of appearance grade was noted. All three methods of freezing provided sufficient preservation for laboratory microsurgical vasovasostomy compared with fresh tissue.