International Collaboration for the Prosthetic and Surgical Intervention of Velopharyngeal Insufficiency.

Interdisciplinary teamwork is essential for the rehabilitation of patients with cleft lip and palate, and therefore, the application of treatment techniques for velopharyngeal insufficiency, both surgical and prosthetic, depends on the experience of each rehabilitation team. For this reason, the following study consisting of the cooperation between interdisciplinary cleft lip and palate teams from Chile and Argentina, which succeeded in correcting velopharyngeal insufficiency in an adolescent, initially using a pharyngeal bulb prosthesis and speech therapy, and finally through pharyngeal flap surgery, is presented. This shows that international cooperation is a valuable tool for training, implementation, and follow-up of different treatment techniques for teams in formation.

Plasticidad muscular y fibras híbridas en la musculatura masticatoria: revisión de literatura / Muscle plasticity and hybrid fibers in the masticatory musculature: literature review

La musculatura masticatoria se caracteriza por presentar fibras híbridas que en los últimos años se han relacionado con el fenómeno de plasticidad muscular. El objetivo del estudio fue describir la relación entre la plasticidad muscular y las fibras musculares híbridas presentes en la musculatura masticatoria, mediante una revisión narrativa de literatura. Para esto, se realizó una búsqueda electrónica en PUBMED, ScienceDirect y BIREME, utilizando las palabras claves: "Muscle Plasticity", "Hybrid Muscle Fibers" y "Hybrid Fibers". Fueron seleccionados documentos que reportan las isoformas de cadena pesada de miosina (MHC) presentes en los músculos masticatorios de humanos y otros mamíferos, junto a los cambios vinculados a demandas funcionales. Se describe la presencia de fibras puras tipo I y tipo II, además de otras isoformas como la MHC-la, MHC-IIM, MHC-fetal y MHC-cardíaca. Sin embargo, un porcentaje considerable de fibras en la musculatura masticatoria son híbridas, es decir, expresan a más de una isoforma de MHC, las cuales también son diferentes a nivel intermuscular e intramuscular. Las influencias locales pueden contribuir a la variación de la expresión del tipo de fibra. En la musculatura masticatoria, el destete, la dureza de los alimentos, el bruxismo, la morfología craneofacial y el uso de prótesis dentales genera cambios a nivel de los músculos masticatorios, donde es común la presencia de fibras híbridas. Se concluye la presencia importante de fibras híbridas en la musculatura masticatoria y su relación con la plasticidad muscular a lo largo del ciclo vital, debido a cambios funcionales y patológicos. Es importante que los terapeutas de habla y motricidad orofacial profundicen en el conocimiento de la fisiología del comportamiento oromiofuncional.

The masticatory musculature is characterized by presenting hybrid fibers that in recent years have been related to the phenomenon of muscle plasticity. The objective of the study was to describe the relationship between muscle plasticity and the hybrid muscle fibers present in the masticatory muscles, through a narrative review. For this, an electronic search was conducted in PUBMED, ScienceDirect and BIREME, using the keywords: "Muscle Plasticity", "Hybrid Muscle Fibers" and "Hybrid Fibers". Documents that report the myosin heavy chain (MHC) isoforms present in the masticatory muscles of humans and other mammals were selected, along with the changes linked to functional demands. The presence of type I and type II pure fibers were described, in addition to other isoforms such as MHC-la, MHC-IIM, MHC-fetal and MHC-cardiac. However, a significant percentage of fibers in the masticatory muscles are hybrids, that is, they express more than one MHC isoform, which are also different at the intermuscular and intramuscular level. Local influences can contribute to the variation of fiber type expression. In the chewing muscles, weaning, the hardness of food, bruxism, craniofacial morphology and the use of dental prostheses generate changes at the level of the chewing muscles, where the presence of hybrid fibers is common. The important presence of hybrid fibers in the masticatory muscles and their relationship with muscle plasticity throughout the life cycle, due to functional and pathological changes, is concluded. It is important for Speech Therapy andMyofunctional Therapy to deepen their understanding of the physiology of oromyofunctional behavior.