Reconstruction of ureteral defects with microvascular vein grafts in a rat model

Reconstruction of parotid duct defect with autologous vein graft and vascular coupler after buccal mucosa cancer resection

The distal end of parotid duct is often inevitably resected en-block with the buccal mucosa cancer to obtain safety margin and prevent local recurrence. Ligation of duct frequently causes complications like cheek swelling, fistula and gland function loss. The authors describe a novel procedure of combined use of autologous vein graft and vascular coupler to reconstruct the parotid duct defect for buccal mucosa cancer patients who undergo radical neck dissection and free-flap reconstruction, no lumen-stent or cannula is needed. Case examples are shown to illustrate the operative details and different outcomes for two kinds of orifice site choices. Key factors for success include the proper use of Coupler device, right choice of new orifice location and maintenance of lumen patency. For buccal mucosa cancer patients, this novel method for parotid duct reconstruction could effectively reduce postoperative complications and preserve the parotid gland function.

Ureter regeneration-the proper scaffold has to be defined

The aim of this study was to compare two different acellular scaffolds: natural and synthetic, for urinary conduit construction and ureter segment reconstruction. Acellular aortic arch (AAM) and poly(L-lactide-co-caprolactone) (PLCL) were used in 24 rats for ureter reconstruction in both tested groups. Follow-up period was 4 weeks. Intravenous pyelography, histological and immunohistochemical analysis were performed. All animals survived surgical procedures. Patent uretero-conduit junction was observed only in one case using PLCL. In case of ureter segment reconstruction ureters were patent in one case using AAM and in four cases using PLCL scaffolds. Regeneration of urothelium layer and focal regeneration of smooth muscle layer was observed on both tested scaffolds. Obtained results indicates that synthetic acellular PLCL scaffolds showed better properties for ureter reconstruction than naturally derived acellular aortic arch.

Tissue engineered venous matrices for potential applications in the urogenital tract

Tissue engineering is lacking inexpensive, easily applicable techniques for tissue replacement. We investigated the potential use of native veins for tissue-engineering applications in the urological field. Forty-eight porcine veins, half seeded with urothelial cells and half unseeded, were kept in vitro for 7 days. Four seeded and four unseeded scaffolds were analyzed after 3 and 7 days. The remaining 32 veins were implanted subcutaneously into 16 athymic mice. Four athymic mice were sacrificed after 2, 4, 8, and 12 weeks. Histochemistry, immunohistochemistry (anti-pancytokeratin AE1/AE3, anti-desmin), western blot analyses (CD31), and scanning electron microscopy were performed in the retrieved specimens. The histochemistry of the seeded matrices showed the presence of urothelial cells in vitro and in vivo. After 12 weeks, a multilayer of urothelial cells was present in the hemotoxylin and eosin staining, positive for anti-pancytokeratin AE1/AE3. The western blot analyses showed vascularization of the veins in vivo. The results of scanning electron microscopy revealed a cellular layer on the veins. Native venous matrices may be used as tissue-engineered constructs for reconstructing the urinary tract. The clinical relevance of this approach must be proven in a large-animal model.

Reconstruction of Traumatic Stensen Duct Defect Using a Vein Graft as a Conduit: Two Case Reports

Treatment of Stensen duct defect is still controversial. The authors describe the successful use of a retrograde vein graft as a conduit for traumatic segmental Stensen duct defect reconstruction. One patient sustained facial trauma with severe duct crushing and severance, the other had multiple cutting injuries with segmental duct defect. However, primary repair was impossible. A retrograde vein graft harvested from forearm for Stensen duct defect reconstruction was performed using microsurgical technique. A silicon stent was retained for 8 weeks. The sialographic examination showed good functional results without stricture postoperatively. This could be an option for treating such a complicated defect.