The previously undescribed variant of the thyrohyoid muscle and its potential impact on surgical procedures

The thyrohyoid muscle belongs to the infrahyoid group located in the carotid triangle. It normally originates from thyroid cartilage and inserts into hyoid bone. Quite often, it is continuous with the sternohyoid muscle. Furthermore, there are variants that have their origin in the cricoid cartilage only, however, this occurs very rarely. During anatomical dissection, a two-headed variant of this muscle was found. One head had its origin in the cricoid cartilage and the other in the thyroid cartilage. This variant of thyrohyoid had not been previously described in the available literature. Therefore, we believe that it may be referred to as the cricothyrohyoid muscle. As the thyrohyoideus is often used as a landmark during surgical procedures in the prelaryngeal area and as a muscle graft, a thorough knowledge of its anatomy and variation is extremely important. We speculate that the two-headed version of this muscle may be problematic during surgical procedures in this region, however, it may also provide more options as a muscular graft.

Duplication of the Hypoglossal Nerve Branch to the Thyrohyoid Muscle: A Case Report

The motor fibers to the thyrohyoid muscle are provided by the anterior ramus of C1 via the hypoglossal nerve rather than via the ansa cervicalis. Knowledge of possible variations in the branching patterns of the nerves attached to the hypoglossal nerve is necessary to minimize iatrogenic injury to these structures during surgical procedures. We describe a rare anatomical variant of the nerve branch to the thyrohyoid muscle. To our knowledge, this particular variant has not been previously reported.

Laryngeal reinnervation for paediatric vocal cord palsy: a systematic review

OBJECTIVE

This systematic review aims to provide an overview of the current evidence-base for paediatric surgical reinnervation in unilateral and bilateral vocal fold palsies in clinical practice. We aim to assess patient demographics, surgical technique and pre- and post-operative outcome measures.

METHODS

A systematic literature review was performed and reported according to international PRISMA recommendations. A comprehensive search of PubMed, Embase, and Cochrane CENTRAL databases for relevant publications for all available dates with appropriate MESH search criteria was performed. Articles were categorised by four authors independently. A pooled summative analysis was carried out to allow review of demographic and outcome data.

RESULTS

Our systematic PRISMA approach resulted in 19 papers being selected for inclusion and analysis with 179 patients undergoing reinnervation (153 unilateral, 26 bilateral). The youngest patient was 1.9 years. Iatrogenic injury to recurrent laryngeal nerve most common aetiology (65.4% and 19.2% of unilateral and bilateral vocal fold palsies, respectively). Patent ductus arteriosus ligation was the single most common procedure resulting in unilateral vocal fold palsies (43.1% of cases). Statistically significant improvements in subjective and objective outcomes for both voice and swallowing were seen. Meta-analysis was able to be performed on the particularly evident improvements in GRBAS score and Maximum Phonation Time (MPT). GRBAS scores improved by 3.64 (p < 0.01, 95% CI 2.65 to 4.63). MPT showed a statistically significant improvement of 5.26 s (p < 0.05, 95% CI 4.28 to 6.24). No major complications were reported.

CONCLUSION

The current published evidence on one-hundred and seventy-nine paediatric surgical reinnervation procedures demonstrates its role as a safe and effective treatment for both unilateral and bilateral vocal fold palsies. Anatomically it has been shown to improve vocal fold tone, bulk and position. Both post-operative voice and swallowing outcomes show improvement as well as associated quality of life measures.

Ultrasound of the vocal cords in infants

Vocal cord paralysis is a common cause of respiratory and feeding problems in the pediatric population. While the causes of vocal cord paralysis are multiple, iatrogenic injury of the recurrent laryngeal nerve after cardiovascular surgery is the most frequent cause. Vocal cord paralysis increases the risk of swallowing dysfunction, tracheal aspiration and pneumonia. It also increases the need for nasoenteric feeds and gastrostomy tube placement. Flexible nasopharyngolaryngoscopy is considered the gold standard for diagnosing vocal cord paralysis, but it has significant drawbacks: it is uncomfortable, it can trigger a cardiovascular event in children with unstable cardiovascular status, it can be challenging to perform, and it can be difficult to interpret. Laryngeal US has become a popular imaging modality to evaluate the function of the vocal cords. Laryngeal US is well-tolerated, easy to perform, simple to interpret and has a lower physiological impact compared to flexible nasopharyngolaryngoscopy. Laryngeal US is an accurate and low-cost diagnostic test for vocal cord paralysis. In this review, we describe the anatomy of the larynx and recurrent laryngeal nerve; the causes, symptoms and pathophysiology of vocal cord paralysis; laryngeal US technique; diagnostic criteria for vocal cord paralysis; and a reporting system.

Surgical interventions for pediatric unilateral vocal fold paralysis: A systematic review and meta-analysis

OBJECTIVE

To evaluate outcomes of injection laryngoplasty (IL) and laryngeal reinnervation for the treatment of pediatric Unilateral Vocal Fold Paralysis (UVFP), especially on swallowing and quality of voice.

METHODS

A literature review was performed in Medline/PubMed and Cochrane Library, following PRISMA guidelines, with no constraints on publication date. We included studies in English, Portuguese or Spanish about surgical treatment for UVFP on the pediatric population (0-21 years) that documented outcomes for one of the following techniques: IL or laryngeal reinnervation. Study characteristics, patient demographics, technical aspects of each procedure, complications, and outcomes for voice and swallowing were extracted. A meta-analysis with inverse variance, random-effects model was performed.

RESULTS

The PRISMA approach yielded 22 studies, totaling 267 patients. Seven reinnervation articles were included in meta-analysis for maximum phonation time (MPT) and quality of voice measured by Grade, Roughness, Breathiness, Asthenia and Strain (GRBAS) scale. Cardiac surgery had caused UVFP in 62.8% (142/226) of the cases. The main indication for IL was aspiration and for reinnervation was dysphonia. For IL, there was an improvement of 84.5% (confidence interval [CI] 82.6-88.4%) in swallowing and 81.4% (CI 74.6-88.1%) in voice. For reinnervation, there was an improvement of 91.6% (CI 88.2-94.9%) in swallowing and 96.8% (CI 95.5-98.0%) in voice. We found an increase of 6.19 s (CI 1.00 to 11.38) in MPT and a mean difference in GRBAS sum of -3.53 points (CI -6.15 to -0.91) after reinnervation.

CONCLUSION

Retrospective cohort studies suggest that injection laryngoplasty and reinnervation are both effective in improving swallowing and voice in children with UVFP. There was clinical evidence of improvement in the MPT and GRBAS scale meta-analysis in patients undergoing reinnervation.

Surgical Options for Pediatric Bilateral Vocal Cord Palsy: State of the Art

Management of pediatric bilateral vocal cord palsy (BVCP) is a controversial and challenging topic. It may represent a severe obstructive condition usually associated with respiratory distress, and, in such condition, tracheostomy has been considered the gold standard for a long time. Many surgical options have been described and used to increase the glottic space in BVCP (1), with ongoing research of less invasive techniques. The challenge and current trend in our department and in many major pediatric centers is to avoid tracheotomy through an early treatment. Many techniques introduced in the last decade reduced the number of tracheotomies and increased the decannulation rate. Furthermore, we observed a recent increase in attention to preserve the quality of the voice with new techniques, such as endoscopic arytenoid abduction lateropexy which is in our opinion an important innovation to improve glottic space with satisfactory voice results. We present a review of the literature about the evolution of the treatment options for pediatric BVCP during the years.