Oral airway flow dynamics in healthy humans

Oral airway resistance (RO) is an important determinant of oro-nasal partitioning of airflow (e.g. during exercise and sleep); however, little is known of factors influencing its magnitude and measurement.We developed a non-invasive standardized technique for measuring RO (based on a modification of posterior rhinomanometry) and examined inspiratory RO in 17 healthy male subjects (age, 36 ± 2 years (mean ±s.e.m.); height, 177 ± 2 cm; weight, 83 ± 3 kg).Inspiratory RO (at 0.4 ls−1) was 0.86 ± 0.23 cmH2O l−1 s−1 during resting mouthpiece breathing in the upright posture. RO was unaffected by assumption of the supine posture, tended to decrease with head and neck extension and increased to 1.22 ± 0.19 cmH2O l−1 s−1 (n = 10 subjects, P < 0.01) with 40–45 deg of head and neck flexion. When breathing via a mouth-mask RO was 2.98 ± 0.42 cmH2O l−1 s−1 (n = 7) and not significantly different from nasal airway resistance.Thus, in awake healthy male subjects with constant jaw position, RO is unaffected by body posture but increases with modest degrees of head and neck flexion. This influence on upper airway patency may be important when oral route breathing is associated with alterations in head and neck position, e.g. during sleep

Biologic augmentation of rotator cuff repair

Rotator cuff repair is a common orthopedic procedure. Despite advances in surgical technique, the rotator cuff tendons often fail to heal after surgery. In recent years, a number of biologic strategies have been developed and tested to augment healing after rotator cuff repair. These strategies include allograft, extracellular matrices (ECMs), platelet rich plasma (PRP), growth factors, stem cells, and gene therapy. This chapter reviews the most current research on biologic augmentation of rotator cuff repair using these methods