Comparison of partial urethral replacement with acellular matrix versus spontaneous urethral regeneration in a canine model.
OBJECTIVE
To determine whether acellular matrix could be used for partial urethral replacement and to compare regeneration over acellular matrix versus normal spontaneous urethral regeneration.


METHODS
The study included 21 male mongrel dogs in which a 3-cm segment including half of the urethral circumference was excised. In 13 dogs (study group), the defect was covered by acellular matrix of the same length and width obtained from female mongrel dogs and prepared to have complete cell lysis with keeping of the fiber framework. In 8 dogs (control group), the urethral defect was not covered by any urethral tissue. In both groups, an 8F feeding tube was kept inside the urethra for a mean duration of 2 weeks. In the study group, dogs were sacrificed at 1 week, 2 weeks, 3 weeks and then one dog every month for 10 months. In the control group, one dog was sacrificed every month for 8 months.


RESULTS
All dogs survived the procedure. In the study group, 10 dogs underwent urethrogram; 8 were normal, 1 had diverticulum and 1 had relative narrowing. In the control group, 6 dogs underwent urethrogram; 5 were normal and 1 showed relative narrowing. Histopathological examination of the study group showed gradual regeneration over the acellular matrix with normal appearance at 20 weeks. In the control group, normal healing was observed at 2 months and thereafter.


CONCLUSIONS
Regeneration of all components of the urethra can occur gradually over acellular matrix and is complete at 20 weeks. Regeneration of a urethral defect 3-cm long including half of the urethral lumen is possible with or without acellular matrix.
Urology and Nephrology Center, Mansoura University, Algomhoria Street, 35516 Mansoura, Egypt. ahmedshokeir@hotmail.com
Ahmed
A
Shokeir
Yasser
Y
Osman
Mohamed
M
El-Sherbiny
Mahmoud
M
Gabr
Tarek
T
Mohsen
Mahmoud
M
El-Baz
D000818:Animals; D004285:Dogs; D005109:Extracellular Matrix / Q000637:transplantation*; D011859:Radiography; D019651:Plastic Surgery Procedures; D014521:Urethra / Q000000981:diagnostic imaging / Q000601:surgery*; D013520:Urologic Surgical Procedures