Mechanical characterization of soft-tissue stiffness during mandibular distraction.

The purpose of this study was to determine the stiffness of mandibular soft tissues during mandibular distraction, from the perspective of improving distraction devices such as automated continuous distractors. Uncompleted osteotomy was performed on 11 fresh human hemimandibles via a greenstick fracture, to preserve the uplift of the internal periosteum of the mandibular corpus. In order to replicate continuous distraction, direct measurements were performed through a uniaxial quasi-static tensile test. For all specimens, linear regression was applied to the force-displacement curve for a force region of 10-20 N, and the slope extracted. The mean stiffness was estimated to be 9.12 ± 3.56 N/mm. This study is the first to measure directly the stiffness of the surrounding tissues of the human mandibular corpus, and paves the way to the design of a new generation of distractor devices.

Management after fibula free flap necrosis in maxillofacial reconstruction.

INTRODUCTION: Few articles discuss the management of a free fibula flap (FFF) necrosis in maxillofacial reconstruction. MATERIAL & METHODS: Between 2005 and 2020, 170 FFF were used for maxillofacial reconstruction at the University Hospital of Caen, among which 16 cases suffered total necrosis and flap removal. The authors categorized these 16 cases into three groups based on the proposed salvage treatment and analyzed the post-operative follow-up, including complications, length of hospital stay and delay in radiotherapy. RESULTS: In Group A, two patients underwent immediate reconstruction with a new free flap. There were no postoperative complications, and the average hospitalization duration after removal of the first flap was 10 days. In Group B, eleven patients underwent reconstruction with a pedicled musculocutaneous pectoralis major flap. These patients experienced numerous complications, with 73% of them requiring at least one additional surgery, and all of them had an indication for later FFF reconstruction. The average hospitalization duration in this group was 37 days. In Group C, three patients underwent conservative management with debridement and mucosal closure. Two of them experienced complications, and all of them underwent later FFF reconstruction. The average hospitalization duration in this group was 15 days. DISCUSSION: Based on our experience and the literature review, the use of an immediate new free flap appears to be the best approach after the removal of a FFF. This generates shorter healing times and shorter hospitalization stays, and this allows better results in terms of function and aesthetics. At least, this is the approach that causes the least delay for radiation therapy if indicated. The other approaches should only be proposed in case of patient's poor general condition or in case of refuse of the patient.

Rerouting the internal thoracic vessels as recipient vessels in head and neck reconstruction: Comparison of two anatomic approaches.

INTRODUCTION: The vessel-depleted neck situation is a challenge for the surgeon in search of suitable recipient vessels for microvascular reconstruction of the head and neck. The internal thoracic vessels (ITVs) have proven useful as "rescue" recipient vessel resource. The objective of this report is to assess the feasibility of using ITVs by rerouting the pedicle for free flap reconstruction of the head and neck by comparing two different approaches. MATERIAL AND METHODS: Two surgical approaches were assessed: the classical one is parasternal, but cardiac surgeons commonly use median sternotomy. We conducted an anatomical study, comparing on the same subject the lengths and diameters of both internal thoracic artery (ITA) and internal thoracic vein (ITV) at the sixth, fifth, and fourth intercostal spaces (ICSs) through parasternal approach on one side and by median sternotomy on the other side. RESULTS: The study was performed on 13 subjects. We found a superiority of length of the ITVs with the median sternotomy approach. Regarding the mean length of the ITA, the sternotomy approach allowed a significant greater length with 119/89/67 mm, compared with parasternal approach with 91/62/42 mm, respectively at the sixth, fifth, and fourth ICS (p<0.001). Similarly, we observed a significant greater length of the ITV with 116/85/63 mm versus 89/62/42 mm (p<0.001). The mean arterial and venous diameters were 2.9 mm and 2.1 mm in the sixth ICS, 3.3 mm and 2.3 mm in the fifth ICS, and 3.9 mm and 2.9 mm in the fourth ICS, respectively. CONCLUSION: These results help to guide the choice of surgical approach and the level of harvesting.