Mechanical properties of animal ligaments: a review and comparative study for the identification of the most suitable human ligament surrogates.

The interest in the properties of animal soft tissues is often related to the desire to find an animal model to replace human counterparts due to the unsteady availability of human tissues for experimental purposes. Once the most appropriate animal model is identified, it is possible to carry out ex-vivo and in-vivo studies for the repair of ligamentous tissues and performance testing of replacement and support healing devices. This work aims to present a systematic review of the mechanical properties of ligaments reported in the scientific literature by considering different anatomical regions in humans and several animal species. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. Moreover, considering the lack of a standard protocol for preconditioning of tissues, this aspect is also addressed. Ninety-six studies were selected for the systematic review and analysed. The mechanical properties of different animal species are reported and summarised in tables. Only results from studies reporting the strain rate parameter were considered for comparison with human ligaments, as they were deemed more reliable. Elastic modulus, ultimate tensile stress, and ultimate strain properties are graphically reported identifying the range of values for each animal species and to facilitate comparison between values reported in the scientific literature in animal and human ligaments. Useful similarities between the mechanical properties of swine, cow, and rat and human ligaments have been found.

[Submental intubation for airway management in patients with middle third facial skeleton fractures]. / La intubación submentoniana en el manejo de la vía aérea de pacientes con fracturas de tercio medio facial.

INTRODUCTION: Airway management in patients with middle third facial skeleton fractures is a challenge for anesthesiologists and surgeons, given that the natural routes for intubation--the nose and mouth--are both compromised by trauma. In this setting, the airway can only be accessed by tracheotomy. Tracheotomy, however, is an invasive technique that should be reserved for cases in which it is absolutely necessary. OBJECTIVES: To establish the utility of submental intubation as an alternative to tracheotomy in patients with middle third facial skeletal fractures. PATIENTS AND METHODS: We reviewed the cases of the 15 patients intubated with the aforementioned technique between 1996 and 2002 in Hospital Universitario La Paz in Madrid, Spain. We describe the surgical technique and postoperative course recorded for those patients. RESULTS: The courses of surgery and postoperative recovery were without complications. All extubations were uneventful and no patient required a tracheotomy. CONCLUSIONS: Submental intubation is a simple, useful technique for managing the airway of patients with middle third facial skeletal fractures. The technique has few complications.