Faculty Bibliography

In vivo reconstitution of the dTDP-D-desosamine pathway of the megalomicin gene cluster from Micromonospora megalomicea was achieved by expression of the genes in Escherichia coli. LC/MS/MS analysis of the dTDP-sugar intermediates produced by operons containing different sets of genes showed that production of dTDP-D-desosamine from dtdp-4-keto-6-deoxy-D-glucose requires only four biosynthetic steps, catalysed by MegCIV, MegCV, MegDII and MegDIII, and that MegCII is not involved. Instead, bioconversion studies demonstrated that MegCII is needed together with MegCIII to catalyse transfer of D-desosamine to 3-alpha-mycarosylerythronolide B.

Various local and distant flaps have been used to repair pelvic defects, including sartorius, rectus abdominis, rectus femoris, tensor fascia lata, vastus lateralis, gracilis, and omentum, each with benefits and disadvantages. The pedicled internal oblique rotational muscle flap has been described to cover pelvic wounds but may be underutilized. We present our experience with 5 pedicled internal oblique flaps in 4 patients (3 male, 1 female). The mean patient age was 32 years (23-47 years), and the mean follow-up was 8 months. All patients required coverage of the lateral pelvis after failure of conservative measures. There were no major complications. One patient experienced decreased sensation in the lateral femoral cutaneous nerve distribution, which resolved fully within 3 months. The internal oblique muscle provides local soft-tissue coverage with a predictable blood supply, and its proximity to the pelvis offers an alternative for reconstruction of lateral pelvic defects, with minimal associated morbidity.

A 50-year-old right-handed male presented with a previously incompletely excised low-grade fibrous histiocytoma on his distal radial palmar forearm. Reoperative wide resection resulted in a segmental defect of the radial artery and a large soft-tissue defect with exposed tendons denuded of paratenon. An arterialized venous fasciocutaneous flow-through flap, measuring 8 x 3 cm, was harvested from the dorsal ipsilateral hand and used to reconstruct both the soft-tissue and the segmental radial-artery defects. A full-thickness skin graft was harvested from the ipsilateral groin to cover the dorsal hand wound. Moderate venous congestion was noted in the flap on postoperative day 1 and treated with four days of leeches. Approximately 10 percent of the flap was lost due to the venous congestion. The flap healed well without further complications. At 33 months the flap remained well-perfused, with excellent flow through the reconstructed radial artery evidenced by both clinical examination and by color vascular Doppler exam. The patient had full range of motion in his right hand despite initial postoperative stiffness and reported no cold intolerance in the right hand. There has been no local recurrence of the sarcoma. The authors believe that this is the largest arterialized venous flow-through flap currently reported to have survived, as well as the first reported case of its use for the simultaneous reconstruction of a radial artery defect and an associated soft-tissue loss.

The use of prosthetic mesh for the tension-free repair of incisional hernias has been shown to be more effective than primary suture repair. Unfortunately, prosthetic materials can be a suboptimal choice in a variety of clinical scenarios. In general, prosthetic materials should not be implanted into sites with known contamination or infection because they lack an endogenous vascular network and are thus incapable of clearing bacteria. This is of particular relevance to the repair of recurrent hernias, which are often refractory to repair because of indolent bacterial colonization that weakens the site and retards appropriate healing. Although fascia lata grafts and muscle flaps can be employed for tension-free hernia repairs, they carry the potential for significant donor site morbidity. Recently, a growing number of clinicians have used human acellular dermal matrix as a graft material for the tension-free repair of ventral hernias. This material has been shown to become revascularized in both animal and human subjects. Once repopulated with a vascular network, this graft material is theoretically capable of clearing bacteria, a property not found in prosthetic graft materials. Unlike autologous materials such as fascial grafts and muscle flaps, acellular dermal matrix can be used without subjecting the patient to additional morbidity in the form of donor site complications. This article presents a thorough review of the current literature, describing the properties of human acellular dermal matrix and discussing both animal and human studies of its clinical performance. In addition to the review of previously published clinical experiences, we discuss our own preliminary results with the use of acellular dermal matrix for ventral hernia repair in 46 patients.

Auricular composite grafts are a useful reconstructive option, particularly for nasal reconstruction. This study evaluates the effect of hyperbaric oxygen (HBO) therapy on auricular composite graft survival in rabbits. Circular chondrocutaneous composite grafts of 0.5, 1, or 2 cm in diameter were resected from the ears of rabbits. The grafts were sutured back into position. Half the rabbits in each group received HBO postoperatively, consisting of 90 minutes at 2.4 atm. Rabbits received 7 treatments in 5 days. Control rabbits did not receive HBO. On day 21 the percentage area of graft survival was calculated from gross and histologic examination. Two-centimeter grafts treated with HBO (n = 8) had a mean graft survival rate of 85.8 +/- 15.7% compared with a survival rate of 51.31 +/- 38.5% for the control group (n = 8; P = 0.0478). There was no such benefit in smaller grafts. HBO could prove clinically useful for larger composite grafts.

This study investigates whether human acellular dermis (Alloderm; LifeCell, Branchburg, NJ) revascularizes when used to reconstruct abdominal wall defects in rabbits. This could prove useful in infected situations in which prosthetic mesh is suboptimal. Twenty-five rabbits were randomly assigned to one of three groups: primary closure (n = 5), expanded polytetrafluoroethylene (GoreTex; W.L. Gore, Flagstaff, AZ) repair (n = 10), or AlloDerm (LifeCell) repair (n = 10). The rabbits in the primary closure group received a 7 cm x 0.5 cm full-thickness abdominal wall defect that was closed primarily. A 7 cm x 3 cm full-thickness abdominal wall defect was created in the other two groups. The defects were repaired with a GoreTex Mycromesh (W.L. Gore), or AlloDerm (LifeCell) patch. At 30 days, the following endpoints were evaluated: (1) incidence of herniation; (2) presence of intra-abdominal adhesions; (3) the breaking strength of the patch-fascial interface; and (4) evaluation of graft vascularization by fluorescein dye infusion and histological analysis. There was no incidence of herniation in any of the rabbits. Visceral adhesions to the patch were found in all animals in the Gore-Tex (W.L. Gore) group but in none in the AlloDerm (LifeCell) group. The size of the patch was unchanged in all the rabbits except for two rabbits in the AlloDerm (LifeCell) group that stretched 1 cm in the transverse dimension. The change in size was not statistically significant (p = 0.17) when compared with the change in size in the Gore-Tex (W.L. Gore) group. The mean breaking strength of the primary closure group was significantly higher (521.2 N/mm2 +/- 223.0) than that of the two patch-repair groups (p < 0.05). But there was no significant difference between the mean breaking strength of the AlloDerm (LifeCell) fascial interface (288.6 N/mm2 +/- 97.1 SD) and that of the Gore-Tex (W.L. Gore) fascial interface (337.0 N/mm2 +/- 141.2). Fluorescein dye infusion and histological analysis confirmed vascularization of the AlloDerm (LifeCell) graft. This study demonstrates that AlloDerm (LifeCell) does become vascularized when used as a fascial interposition graft for abdominal wall reconstruction. AlloDerm (LifeCell) also performs mechanically as effectively as Gore-Tex (W.L. Gore) in ventral hernia repair at 1 month after operation in the rabbit model.

Surgical resection of aggressive solid or multicystic ameloblastoma is a well-documented and accepted treatment modality. Controversies exist, however, with regard to the extent of operative intervention. Unresectable lesions have been treated with radiation or combined radiation and chemotherapy. The authors present a case report of a patient with recurrent ameloblastoma who underwent simultaneous hard- and soft-tissue reconstruction.