Recovery of laryngeal function after intraoperative injury to the recurrent laryngeal nerve
TL;DR: This review aims to provide an update on the current understandings of surgically-induced injury to the laryngeal nerves to clarify any differences between the transient and permanent injury of the RLN.
Abstract: Loss of function in the recurrent laryngeal nerve (RLN) during thyroid/parathyroid surgery, despite a macroscopically intact nerve, is a challenge which highlights the sensitivity and complexity of laryngeal innervation. Furthermore, the uncertain prognosis stresses a lack of capability to diagnose the reason behind the impaired function. There is a great deal of literature considering risk factors, surgical technique and mechanisms outside the nerve affecting the incidence of RLN paresis during surgery. To be able to prognosticate recovery in cases of laryngeal dysfunction and voice changes after thyroid surgery, the surgeon would first need to define the presence, location, and type of laryngeal nerve injury. There is little data describing the events within the nerve and the neurobiological reasons for the impaired function related to potential recovery and prognosis. In addition, very little data has been presented in order to clarify any differences between the transient and permanent injury of the RLN. This review aims, from an anatomical and neurobiological perspective, to provide an update on the current understandings of surgically-induced injury to the laryngeal nerves.
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TL;DR: This study evaluates the impact of intraoperative EMG changes on synchronous vocal cord contractility by simultaneous use of continuous intraoperative neuromonitoring (C‐IONM) and accelerometry for registration of actual vocal cord function at a given change of EMG amplitude.
Abstract: Objective Gradual impairment of nerve conduction is expected to be tightly associated with simultaneous gradual loss of vocal cord contractility, related to the fact that injured axons are connected to a defined number of muscle cells. In clinical studies, there is a time gap between observed adverse electromyographic (EMG) changes and examination of vocal cord function. This study evaluates the impact of intraoperative EMG changes on synchronous vocal cord contractility by simultaneous use of continuous intraoperative neuromonitoring (C-IONM) and accelerometry for registration of actual vocal cord function at a given change of EMG amplitude. Methods EMG was obtained following vagus nerve stimulation by use of C-IONM. A vocal cord accelerometer probe that could be attached to the vocal cords was developed based on a LIS3DH ultra low-power high performance three axis linear accelerometer (STMicroelectronics, Geneva, Switzerland). Accelerometer data were registered continuously together with EMG data during traction injury of the recurrent laryngeal nerve (RLN) until an amplitude depression ≤100 μV. Results Six RLN from four immature domestic pigs were studied. Vocal cord contractility assessed by vocal cord accelerometry decreased in parallel with EMG amplitude, with significant correlations ranging from 0.707 to 0.968. Conclusion Decrease of EMG amplitude during traction injury to the RLN injury is closely associated with a parallel drop in vocal cord contractility. Level of evidence NA Laryngoscope, 130:1090-1096, 2020.
3 citations
Cites background or result from "Recovery of laryngeal function afte..."
...This assumption is in accordance with and supports the motor unit model previously described.(12) According to this viewpoint, the use of an EMG recorded by an intramuscular needle electrode seems less robust than an EMG recorded by surface electrode and may therefore represent a limitation of the present study....
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...Based on the well-known model of the motor unit that an axon is connected to a defined number of muscle cells, gradual impairment of nerve conduction should result in gradual loss of contractility of the vocal cord.(12) In all available clinical studies, there is a time gap between observed adverse electromyographic (EMG) changes and the examination of the functional status of the vocal cord....
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01 Jan 2016
TL;DR: Recurrent laryngeal nerve dysfunction is among the most common and feared complications of thyroidectomy and is an increasingly common cause for malpractice suits against endocrine surgeons.
Abstract: Recurrent laryngeal nerve (RLN) dysfunction is among the most common and feared complications of thyroidectomy and is an increasingly common cause for malpractice suits against endocrine surgeons. Temporary or permanent vocal cord palsy may carry a significant burden of disease. Thorough knowledge of the normal anatomy and its variants, a meticulous surgical technique, and a gentle handling of tissues with routine identification of the RLN represent the standard of care for a safe thyroidectomy. Temporary palsy of the RLN occurs in up to 10 % of cases and permanent paralysis in <2 % of patients. Inadvertent injury to the nerve is directly influenced by the common anatomic variations of the RLN along its expected and unexpected cervical course. These variations include the extralaryngeal bifurcation of the RLN that constitutes a frequent event present in up to 30–40 % of cases. Branching of the nerve typically occurs at the level of the ligament of Berry along the distal 1 or 2 cm of the RLN cervical course before its entry into the larynx. Branching of the RLN represents a major risk factor for both transient and permanent nerve palsy. Thus, intraoperative recognition and verification of functional and anatomic integrity of premature division of the nerve is crucial during thyroid operations. Initial studies using intraoperative nerve monitoring suggest that the anterior branch of the bifid RLNs is the one supplying motor fibers to the posterior cricoarytenoid muscle and vocalis muscle. Identification, exposure, and preservation of extralaryngeal branches of the RLN are mandatory and represent basic surgical principles in thyroid surgery to prevent nerve injury and its associated morbidity.
2 citations
DOI•
30 Aug 2019
TL;DR: Compared to what has been done to date, the precocity of the treatment is demonstrated to be a determinant in the future of vocal cord paralysis and the just-in-time use of different techniques improves the results.
Abstract: Introduction and goals: Laryngeal nerve palsy (both superior and inferior) is a typical—but not exclusive—complication of thyroid surgery. The aim of this report is to review its epidemiology, clinical presentation, diagnosis and up-to-date treatments. Abstract: In spite of being a possible thyroid surgery complication, vocal fold palsy is often poorly treated. Diagnosis, an adapted treatment to meet both expectations and reality of the patients or even the time of application are key to obtain a successful outcome that allows them to live a normal life. Conclusions: Contrary to what has been done to date, the precocity of the treatment is demonstrated to be a determinant in the future of vocal cord paralysis. Fast acting—beyond letting time pass by like in the past— and the just-in-time use of different techniques improves the results.
2 citations
Cites background from "Recovery of laryngeal function afte..."
...EXAMEN FÍSICO La evaluación inicial debe orientarse en determinar la existencia de los hallazgos clínicos esperables: disfonía, disfagia, aspiración y estenosis de la vía aérea [27,36]....
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TL;DR: Although there were limitations in the study using domestic pig, including the small sample size, the results are expected to contribute to a decrease in the incidence of RLN damage during esophageal surgery.
Abstract: Purposes. During esophageal surgery, clamping injury and injury associated with the use of energy devices are common mechanisms underlying intraoperative recurrent laryngeal nerve (RLN) damage. Rec...
2 citations
Cites background from "Recovery of laryngeal function afte..."
...In thyroid surgery, the region of Berry’s ligament was the area of greatest risk for RLN injury.(15,16) The main trunk or anterior branch of the RLN frequently swerves anteriorly and becomes fixed to the lateral trachea and cricoid cartilage within the ligament of Berry....
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...Several studies have reported that the region of Berry’s ligament was the area of greatest risk for RLN injury.(15,16) Therefore, some animal studies were carried out to investigate the changes in the electromyographic (EMG) signals during acute RLN traction injury which showed that RLN traction injury resulted in EMG changes, and that early release of the traction before the EMG signal deterioration progressed to signal loss offered a good chance of recovery....
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TL;DR: In this article, a systematic review employing PRISMA guidelines summarizes and discusses the available evidence related to outcome measures used to characterize novel biomaterials in the development phase, and suggests future studies to prioritize characterization of the viscoelasticity (to improve voice outcomes), inflammatory response (to reduce side effects) and biodegradation (to increase longevity) profiles of newly developed biommaterials.
Abstract: Vocal fold injection is a preferred treatment in glottic insufficiency because it is relatively quick and cost-saving. However, researchers have yet to discover the ideal biomaterial with properties suitable for human vocal fold application. The current systematic review employing PRISMA guidelines summarizes and discusses the available evidence related to outcome measures used to characterize novel biomaterials in the development phase. The literature search of related articles published within January 2010 to March 2021 was conducted using Scopus, Web of Science (WoS), Google Scholar and PubMed databases. The search identified 6240 potentially relevant records, which were screened and appraised to include 15 relevant articles based on the inclusion and exclusion criteria. The current study highlights that the characterization methods were inconsistent throughout the different studies. While rheologic outcome measures (viscosity, elasticity and shear) were most widely utilized, there appear to be no target or reference values. Outcome measures such as cellular response and biodegradation should be prioritized as they could mitigate the clinical drawbacks of currently available biomaterials. The review suggests future studies to prioritize characterization of the viscoelasticity (to improve voice outcomes), inflammatory response (to reduce side effects) and biodegradation (to improve longevity) profiles of newly developed biomaterials.
2 citations
References
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1,975 citations
Book•
01 Jan 1983
TL;DR: This book provides a comprehensive review of most peripheral nerve and muscle diseases, including specific techniques and locations for performing each test, and is of value to neurologists and physiatrists who are interested in neuromuscular disorders and noninvasive electrodiagnostic methods.
Abstract: With each subsequent edition, Dr. Kimura has built upon his extensive experience teaching electromyography (EMG) around the world and has transferred his knowledge to the book. It is intended for clinicians who perform electrodiagnostic procedures as an extension of their clinical examination, and will be of value to neurologists and physiatrists who are interested in neuromuscular disorders and noninvasive electrodiagnostic methods, particularly those practicing electromyography (EMG). The book provides a comprehensive review of most peripheral nerve and muscle diseases, including specific techniques and locations for performing each test.New to this edition:intra-operative monitoringstudies for the pediatric and geriatric populationsdata analysis and reporting, which should help facilitate daily practice
1,503 citations
1,187 citations
"Recovery of laryngeal function afte..." refers background in this paper
...These classifications were first made by Seddon in 1942 (46) and later modified by Sunderland in 1951 (47)....
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TL;DR: Basal lamina grafts for reconnecting severed nerves are prepared from muscle by removing cellular material therefrom while preserving the tubular structure of the basal lamina, eventually reestablishing nerve function through the regenerated graft.
Abstract: Basal lamina grafts for reconnecting severed nerves are prepared from muscle by removing cellular material therefrom while preserving the tubular structure of the basal lamina. When connected to nerve stumps the basal lamina surfaces promote axon regeneration therethrough, eventually reestablishing nerve function through the regenerated graft.
965 citations