Laryngotracheal and pharyngoesophageal traumatic injuries from US military operations in Iraq and Afghanistan, 2003-2017.

INTRODUCTION: Laryngotracheal and pharyngo-oesophageal trauma present military providers with especially difficult, life-threatening challenges. Although effective treatment strategies are crucial, there is no clear consensus. This study of combat injuries from Iraq and Afghanistan describes initial treatment outcomes. METHODS: US service members who sustained 'laryngotracheal' and 'pharyngoesophageal' injuries while deployed in military operations from 2003 to 2017 were identified from the Expeditionary Medical Encounter Database. Those with inhalation or ingestion injuries and an Injury Severity Score (ISS) <16 were excluded. Data on demographics, survival, mechanism and type of injury and diagnostic and therapeutic intervention were recorded. RESULTS: A total of 111 service members met inclusion criteria. Nearly one-third (32.4%) were killed in action (KIA) or died of wounds (DoW). Fatality was not significantly associated with age, theatre of operation, type of injury or mechanism of injury, but was associated with a higher ISS and those in the Marines. Although survival rates were not significantly different, the frequency of these injuries decreased after the introduction of cervical collar protection in 2007. Of those who DoW or survived, 41.1% required a surgical airway. Tracheobronchoscopy was performed in 25.6%, oesophagoscopy in 20.0% and oesophagram in 6.7%. Of the 85 with penetrating neck injuries, 43 (50.6%) underwent neck exploration, in which 31 (72.1%) required intervention. CONCLUSIONS: Severe laryngotracheal and pharyngo-oesophageal injuries have a high fatality rate and demand prompt treatment from skilled providers. Further work will elucidate preventive measures and clear management algorithms to optimise outcomes.

A highly porous 3-dimensional polyphosphazene polymer matrix for skeletal tissue regeneration.

Current methods for the replacement of skeletal tissue in general involve the use of autografts or allografts. There are considerable drawbacks in the use of either of these tissues. In an effort to provide an alternative to traditional graft materials, a degradable 3-dimensional (3-D) osteoblast cell-polymer matrix was designed as a construct for skeletal tissue regeneration. A degradable amino acid containing polymer, poly[(methylphenoxy)(ethyl glycinato) phosphazene], was synthesized and a 3-D matrix system was prepared using a salt leaching technique. This 3-D polyphosphazene polymer matrix system, 3-D-PHOS, was then seeded with osteoblast cells for the creation of a cell-polymer matrix material. The 3-D-PHOS matrix possessed an average pore diameter of 165 microns. Environmental scanning electron microscopy revealed a reconnecting porous network throughout the polymer with an even distribution of pores over the surface of the matrix. Osteoblast cells were found attached and grew on the 3-D-PHOS at a steady rate throughout the 21-day period studied in vitro, in contrast to osteoblast growth kinetics on similar, but 2-D polyphosphazene matrices, that showed a decline in cell growth after 7 days. Characterization of 3-D-PHOS osteoblastpolymer matrices by light microscopy revealed cells growing within the pores as well as on surface of the polymer as early as day 1. This novel porous 3-D-PHOS matrix may be suitable for use as a bioerodible scaffold for regeneration of skeletal tissue.

Use of polyphosphazenes for skeletal tissue regeneration.

The hydrolytically unstable polyphosphazenes, poly [(imidazolyl) (methylphenoxy) phosphazenes] and poly [ethyl glycinato) (methylphenoxy) phosphazenes], were studied as potential polymeric supports for cells in tissue regeneration. For bone repair, their specific function would be to support osteoblast growth, forming a bone-polymer matrix. MC3T3-E1 cells (an osteogenic cell line) were seeded onto polymer matrices and cell adhesion and growth as well as polymer degradation were examined. Both imidazolyl- and ethyl glycinato-substituted polyphosphazenes supported the growth of MC3T3-E1 cells. An increase in the content of the imidazolyl side group resulted in a reduction in cell attachment and growth on the polymer surface and an increase in the rate of degradation of the polymer. In contrast, substitution with the ethyl glycinato group favored increased cell adhesion and growth and also an increase in the rate of degradation of the polymers. Thus, the polyphosphazenes represent a system whereby cell growth and degradation can be modulated by varying the nature of the hydrolytically unstable side chain. This in vitro evaluation suggests that the polyphosphazenes may be suitable candidate biomaterials for the construction of a cell-polymer matrix for tissue regeneration.