Terminal Anatomy of Phrenic Nerve: A Deeper Look at Diaphragm Innervation Patterns.

BACKGROUND: Traumatic brachial plexus injuries are devastating lesions, and neurotization is an usually elected surgical therapy. The phrenic nerve has been harvested as a motor fibers donor in brachial plexus neurotization, showing great results in terms of motor reinnervation. Unfortunately, these interventions lack solid evidence regarding long-term safety and possible late respiratory function sequelae, raising crescent concerns after the COVID-19 pandemic onset and possibly resulting in reduced propensity to use this technique. The study of the distal anatomy of the phrenic nerves may lead to a better understanding of their branching patterns, and thus the proposition of surgical approaches that better preserve patient respiratory function. METHODS: Twenty-one phrenic nerves in 10 formalized cadavers were scrutinized. Prediaphragmatic branching patterns were inspected through analysis of the distance between the piercing site of the nerve at the diaphragm and the cardiac structures, number of divisions, and length from the point where the main trunk emits its branches to the diaphragm. RESULTS: The main trunk of the right phrenic nerve reaches the diaphragm near the inferior vena cava and branches into 3 major divisions. The left phrenic nerve reaches the diaphragm in variable locations near the heart, branching into 2-5 main trunks. Moreover, we noticed a specimen presenting 2 ipsilateral parallel phrenic nerves. CONCLUSIONS: The right phrenic nerve presented greater consistency concerning insertion site, terminal branching point distance to this muscle, and number of rami than the left phrenic nerve.

Workhorse Free Functional Muscle Transfer Techniques for Smile Reanimation in Children with Congenital Facial Palsy: Case Report and Systematic Review of the Literature.

BACKGROUND: Pediatric facial palsy represents a rare multifactorial entity. Facial reanimation restores smiling, thus boosting self-confidence and social integration of the affected children. The purpose of this paper is to present a systematic review of microsurgical workhorse free functional muscle transfer procedures with emphasis on the long-term functional, aesthetic, and psychosocial outcomes. MATERIALS AND METHODS: We performed a literature search of the PubMed database from 1995 to 2019 using the following search strategy: "facial paralysis"[Title/Abstract] OR "facial palsy"[Title]. We used as limits: full text, English language, age younger than 18 years, and humans. Two independent reviewers performed the online screening process using Covidence. Forty articles met the inclusion criteria. The protocol was aligned with the PRISMA statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and was registered at the International Prospective Register of Systematic Reviews (PROSPERO, CRD42019150112) of the National Institute for Health Research. RESULTS: Free functional muscle transfer procedures include mainly segmental gracilis, latissimus dorsi, and pectoralis minor muscle transfer. Facial reanimation procedures with the use of the cross-face nerve graft (CFNG) or masseteric nerve result in almost symmetric smiles. The transplanted muscle grows harmoniously along with the craniofacial skeleton. Muscle function and aesthetic outcomes improve over time. All children presented improved self-esteem, oral commissure opening, facial animation, and speech. CONCLUSIONS: A two-stage CFNG plus an FFMT may restore a spontaneous emotive smile in pediatric facial palsy patients. Superior results of children FFMT compared to adults FFMT are probably attributed to greater brain plasticity.