Tracheal reconstruction using tissue-engineered cartilage.

OBJECTIVES: To determine whether rabbit cartilage can be tissue engineered using a polyglycolic acid (PGA) construct composed of PGA mesh, autologous chondrocytes, and alginate covalently linked with the cell adhesion sequence arginine-glycine-aspartic acid (RGD), and to investigate the feasibility of reconstructing tracheal defects using the PGA construct in conjunction with a bioabsorbable intratracheal stent. METHODS: Nineteen New Zealand White rabbits were used. Nine rabbits underwent subcutaneous implantation of 3 different PGA construct combinations: (1) PGA, autologous chondrocytes, and RGD-modified alginate; (2) PGA, autologous chondrocytes, and unmodified alginate; and (3) PGA and RGD-modified alginate. The remaining 10 animals underwent anterior tracheal reconstruction using fascia lata grafts and the complete PGA construct (PGA, autologous chondrocytes, and RGD-modified alginate). At the time of tracheal reconstruction, a poly-l-lactic acid intratracheal stent was placed in 5 of these latter animals. Rates of tracheal stenosis and mortality were compared with those of historical control animals. Histologic analysis was performed on the PGA constructs. RESULTS: In the subcutaneous implants, the PGA constructs made with chondrocytes (with and without RGD) demonstrated mature cartilage formation in 7 (78%) of the 9 animals. No cartilage was seen in PGA constructs made without chondrocytes. Two of the 10 animals that underwent tracheal reconstruction with the complete PGA construct survived to 20 weeks and demonstrated patent airways, 1 with a stent and 1 without a stent (80% overall mortality). Histologic analysis showed mature cartilage formation at the tracheal reconstruction site. Historical control animals that underwent reconstruction with fascia lata alone demonstrated the lowest overall mortality. CONCLUSIONS: Cartilage can be tissue engineered in rabbits using PGA mesh embedded with alginate-encapsulated autologous chondrocytes. It is also possible to reconstruct tracheal defects with this method of cartilage engineering, although the mortality rate in this study is high.

Management of chyle fistula utilizing thoracoscopic ligation of the thoracic duct.

OBJECTIVES: To document the treatment of refractory chyle leaks using thoracoscopic thoracic duct ligation and provide systematic guidelines to manage chyle leaks. METHODS: The medical records of 2 patients with chyle leaks are reviewed, followed by a review of the literature on chyle leaks and their thoracoscopic management. CONCLUSIONS: Initial treatment of chyle fistula is aimed at conservative medical management. Persistent high-output fistulas (>500 cm(3)) should be considered for neck reexploration as conservative management is likely to fail. Thoracoscopic thoracic duct ligation provides a safe and efficient means of treating chyle leaks refractory to repeated surgical and medical intervention. It should also be considered as a primary surgical intervention for patients with: (1) chyle output exceeding 500 cm(3)/day where prior intraoperative attempts at ligation have failed, (2) severe metabolic and nutritional complications, (3) coexisting chylothorax with respiratory compromise, and (4) low-output fistulas (<500 cm(3)/day) of long duration (>14 days).