Cartilage rods as a potential material for penile reconstruction

Sex assignment is made in patients with ambiguous genitalia, genital trauma or iatrogenic injury after a thorough diagnostic evaluation and careful consultation with the family. In numerous instances a decision is made to rear the child as the female gender due to inadequate genitalia regardless of karyotype. Although a silicone penile prosthesis is accepted treatment in adults who require penile reconstruction, it has not been generally used in the pediatric population, mainly due to associated long-term problems. We determine the feasibility of creating natural penile prostheses of cartilage which, if biocompatible and elastic, may be used in patients who require genital reconstruction.

Cartilage was harvested from the articular surface of calf shoulders. Chondrocytes were isolated, grown and expanded in vitro. Cells were seeded onto preformed cylindrical polyglycolic acid polymer rods 1 cm. in diameter and 3 cm. long at a concentration of 50 x 10(6) chondrocytes per cm.3. A total of 40 polymer scaffolds were implanted in the subcutaneous space of 20 athymic mice. In each mouse 2 implantation sites consisted of a polymer scaffold seeded with chondrocytes and a control (polymer alone). Mice were sacrificed 1, 2, 4 and 6 months after implantation, respectively. Stress relaxation studies to measure biomechanical properties, including compression, tension and bending, were performed on the retrieved structures. Histological analyses were done with hematoxylin and eosin, aldehyde fuchsin-alcian blue and toluidine blue staining.

Gross examination revealed well formed, milk-white rod-shaped solid cartilaginous structures the same size as the initial implant. Compression, tension and bending studies demonstrated that the cartilaginous structures were readily elastic and withstood high degrees of pressure. Histochemical analyses showed mature, well formed chondrocytes in all implants. There was no evidence of cartilage formation in the controls.

Chondrocytes seeded on preformed biodegradable polymer structures form cartilage rods. The use of an entirely autologous system composed of biodegradable polymers and chondrocytes precludes an immunological reaction. This technology appears to be useful for the creation of a biocompatible malleable penile prosthesis, which may be useful in children with ambiguous genitalia and patients undergoing penile reconstruction.