Accuracy of mandibular reconstruction by three-dimensional guided vascularised fibular free flap after segmental mandibulectomy.

Mandibular reconstruction with a fibular free flap has become standard in specialised centres for head and neck reconstruction, particularly for defects with more than one osteotomy that are challenging even for experienced surgeons. Virtual surgical planning is a potential tool to facilitate harvesting of the fibula and the osteostomy. The purpose of this study was to compare the two methods of mandibular reconstruction - conventionally planned (conventional group) and "virtually" planned (virtual group) - with regard to accuracy, bony consolidation, complications, and operating time. Fifty patients who required mandibular reconstruction after segmental mandibulectomy were evaluated retrospectively, 24 virtually planned and 26 conventionally planned. The overall survival of flaps was 92% (46/50). The bony consolidation rate in the virtual group was significantly better than that in the conventional group (p=0.002). The difference between the angle of the mandible before and after was highly significant with a median of 11.5° (range 2°-75°) in the conventional group and 4.5° (range 0-18°) in the virtual group (p=0.0001). Operations were mean (SD) of 34 (21.2) minutes shorter in virtually-planned cases (p=0.12). The overall morbidity did not differ significantly between the groups. The use of virtual surgical planning in mandibular reconstruction by fibular free flap is beneficial for optimising accuracy, consolidation of bony segments, and operating time, while increasing the predictability of results for the surgeon. However, additional costs have to be carefully weighed against the benefits.

Sandwich flaps as a feasible solution for the management of huge mandibular composite tissue defects.

In the current therapy of head and neck defects, surgical reconstruction with the aid of pedicle or free flaps is common practice. Suitable single flaps are available to solve most reconstructive challenges. However, reconstruction can become a problem in extensive mandibular defects, as they are often caused by large primary tumors or osteoradionecrosis. These composite defects often lead to large intraoral or extraoral fistulas due to the involvement of mucosa, skin, mandible and soft tissue. These issues call for a double flap approach in order to achieve adequate reconstruction. Therefore, we developed a surgical sandwich technique as presented in this study. The procedure features the acquisition and use of two vascular flaps which can be freely combined according to their desired features (for example being of high tissue volume or osteomyocutaneous). In our study we included 11 patients (ten male, one female) with a mean age of 57 years. Seven of the patients had defects due to osteoradionecrosis and four due to tumor resection. A sandwich technique was performed in a single operation in eight patients, whereas for three patients several operations were necessary. The flaps used included: fibula free flap (FFF); anterolateral thigh (ALT); radial forearm flap (RFF); deltopectoral flap (DPF) and tensor fascia lata (TFL). The following combinations were used: FFF and ALT (three cases), FFF and RFF (two), FFF and DPF (three), ALT and TFL (two), and two ALT flaps (one). The sandwich technique proved suitable for complex reconstructions and led to desirable esthetic and functional results. The flexibility in combining different free or pedicle flaps made it possible to address various defect situations and consequently offer satisfactory surgical reconstruction for complex cases.

Mutagenesis of the Neisseria gonorrhoeae porin reduces invasion in epithelial cells and enhances phagocyte responsiveness.

Porin (PorB), the major outer membrane protein of Neisseria gonorrhoeae, has been implicated in pathogenesis previously. However, the fact that porin deletion mutants are not viable has complicated investigations. Here, we describe a method of manipulating the porin gene site-specifically. N. gonorrhoeae MS11, which harbours the porB1B (P.1B) porin allele, was used to generate mutants carrying deletions in the surface loops 1 and 5. An 11-amino-acid deletion in loop 1 impaired Opa50-dependent invasion into human Chang epithelial cells, whereas loop 5 deletion exhibited no apparent phenotype. In a second approach, the complete gonococcal porB1B was replaced by the porBNia gene of Neisseria lactamica. Such mutants were unable to induce efficient uptake by epithelial cells but induced an enhanced respiratory response in HL60 phagocytic cells. The increased respiratory burst was accompanied by an enhanced phagocytic uptake of the mutant compared with the wild-type strain. Our data extend previous evidence for multiple central functions of PorB in the infection process.