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Recurrent Laryngeal Nerve (recurrent + laryngeal_nerve)
Terms modified by Recurrent Laryngeal Nerve Selected AbstractsDelivery of an Adenoviral Vector to the Crushed Recurrent Laryngeal Nerve,THE LARYNGOSCOPE, Issue 6 2003Adam Rubin MD Abstract Objectives Objectives were to create a model of recurrent laryngeal nerve injury for testing the efficacy of potential therapeutic viral gene therapy vectors and to demonstrate that remote injection of a viral vector does not cause significant additional neuronal injury. Study Design Animal model. Methods Rats were randomly assigned to three groups of 10 animals each. In group I, the recurrent laryngeal nerve was crushed. In group II, the nerve was crushed and then injected with an adenoviral vector containing no transgene. In group III, the nerve was identified but was not crushed. Rats were killed at 1 week, and their larynges and brainstems were cryosectioned in 15-,m sections. Laryngeal cryosections were processed for acetylcholine histochemical analysis (motor endplates) followed by neurofilament immunoperoxidase (nerve fibers). Percentage of nerve,endplate contact was determined and compared between groups. Fluorescent in situ hybridization was performed on brainstem sections from rats in group II to confirm the presence of virus. Results No significant difference in percentage of nerve,endplate contact exists between the two crushed-nerve groups (groups I and II) (P = .88). The difference between both crushed-nerve groups and the group with noncrushed nerves (group III) was highly significant (P <.0001). The presence of virus was confirmed in group II rats. Conclusions Crush provides a significant measurable injury to the recurrent laryngeal nerve and may be used as a model to explore therapeutic interventions for nerve injury. The remote injection of viral vector did not cause significant additional neuronal injury. Remote delivery of viral vectors to the central nervous system holds promise in the treatment of recurrent laryngeal nerve injury and central nervous system diseases. [source] Penetrating injury at the thoracic inlet in a Paint-Arab mareEQUINE VETERINARY EDUCATION, Issue 12 2009Y. R. Rojman Summary A 12-year-old Paint-Arab mare was admitted for evaluation of a penetrating chest laceration at the thoracic inlet. The left brachiocephalic muscle was transected and the recurrent laryngeal nerve was traumatised. Subsequent to the injury, the horse developed Horner's syndrome on the left side of the neck and face, Grade IV left laryngeal hemiplegia, dysphagia, cough and subcutaneous emphysema. The defect was closed in multiple layers. Antimicrobial and antiinflammatory therapy was instituted along with local wound care. The mare remained bright and responsive and the wound healed normally. The mare showed no signs of respiratory distress. Dysphagia and ptosis persisted at 30 days post trauma. [source] Considerations for pacing of the cricoarytenoid dorsalis muscle by neuroprosthesis in horsesEQUINE VETERINARY JOURNAL, Issue 6 2010N. G. DUCHARME Summary Reasons for performing study: The success rate of prosthetic laryngoplasty is limited and may be associated with significant sequelae. Nerve muscle pedicle transplantation has been attempted but requires a year before function is restored. Objective: To determine the optimal parameters for functional electrical stimulation of the recurrent laryngeal nerve in horses. Methods: An experimental in vivo study was performed on 7 mature horses (2,21 years). A nerve cuff was placed on the distal end of the common trunk of the recurrent laryngeal nerve (RLN). In 6 horses the ipsilateral adductor branch of RLN was also transected. The electrodes were connected to programmable internal stimulator. Stimulation was performed using cathodic phase and then biphasic pulses at 24 Hz with a 0.427 ms pulse duration. Stimulation-response experiments were performed at monthly intervals, from one week following implantation. The study continued until unit failure or the end of project (12 months). Two of the horses were stimulated continuously for 60 min to assess onset of fatigue. Results: Excellent arytenoid cartilage abduction (mean arytenoid angle of 52.7°, range 48.5,56.2°) was obtained in 6 horses (laryngeal grades I or II (n = 3) and III (n = 2). Poor abduction was obtained in grade IV horses (n = 2). Arytenoid abduction was maintained for up to a year in one horse. Technical implant failure resulted in loss of abduction in 6 horses at one week to 11 months post operatively. Mean tissue impedance was 1.06 kOhm (range 0.64,1.67 kOhm) at one week, twice this value at 2 months (mean 2.32, range 1.11,3.75 kOhm) and was stable thereafter. Maximal abduction was achieved at a stimulation range of 0.65,7.2 mA. No electrical leakage was observed. Constant stimulation of the recurrent laryngeal nerve for 60 min led to full abduction without evidence of muscle fatigue. Conclusions: Functional electrical stimulation of the recurrent laryngeal nerve leading to full arytenoid abduction can be achieved. The minimal stimulation amplitude for maximal abduction angle is slightly higher than those for man and dogs. Clinical relevance: This treatment modality could eventually be applicable to horses with recurrent laryngeal neuropathy. [source] Effect of neurotrophin-3 on reinnervation of the larynx using the phrenic nerve transfer techniqueEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2007Paul J. Kingham Abstract Current techniques for reinnervation of the larynx following recurrent laryngeal nerve (RLN) injury are limited by synkinesis, which prevents functional recovery. Treatment with neurotrophins (NT) may enhance nerve regeneration and encourage more accurate reinnervation. This study presents the results of using the phrenic nerve transfer method, combined with NT-3 treatment, to selectively reinnervate the posterior cricoarytenoid (PCA) abductor muscle in a pig nerve injury model. RLN transection altered the phenotype and morphology of laryngeal muscles. In both the PCA and thyroarytenoid (TA) adductor muscle, fast type myosin heavy chain (MyHC) protein was decreased while slow type MyHC was increased. These changes were accompanied with a significant reduction in muscle fibre diameter. Following nerve repair there was a progressive normalization of MyHC phenotype and increased muscle fibre diameter in the PCA but not the TA muscle. This correlated with enhanced abductor function indicating the phrenic nerve accurately reinnervated the PCA muscle. Treatment with NT-3 significantly enhanced phrenic nerve regeneration but led to only a small increase in the number of reinnervated PCA muscle fibres and minimal effect on abductor muscle phenotype and morphology. Therefore, work exploring other growth factors, either alone or in combination with NT-3, is required. [source] Investigation of optimal intensity and safety of electrical nerve stimulation during intraoperative neuromonitoring of the recurrent laryngeal nerve: A prospective porcine model,HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 10 2010Che-Wei Wu MD Abstract Background Intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) has recently been more frequently applied in thyroid surgery. However, concerns have been raised regarding the safety and optimal intensity of electrical nerve stimulation. Methods Eight piglets were enrolled, and electrically evoked electromyography (EMG) was recorded from the vocalis muscles via endotracheal surface electrodes. The baseline EMG was measured and continuous pulsatile stimulations were performed on the vagus nerve and RLN for 10 minutes. Changes of EMG waveform and cardiopulmonary status were analyzed. Results A dose,response curve existed with increasing EMG amplitude as stimulating current was increased, with maximum amplitude elicited on vagal and RLN stimulation at <1 mA. No obvious EMG changes and untoward cardiopulmonary effects were observed after the stimulation. Conclusions Electrical stimulation is safe during IONM in this porcine model. Minimal current that required generating the maximal evoked EMG, approximately 1 mA in this study, can be selected to minimize the risk of nerve damage and cardiopulmonary effects. © 2010 Wiley Periodicals, Inc. Head Neck, 2010 [source] Place and value of the recurrent laryngeal nerve (RLN) palpatory method in preventing RLN palsy during thyroid surgeryHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 4 2009DSci, Áron Altorjay MD Abstract Background. In recent years, certain publications have appeared confirming that intraoperative palpation of the recurrent laryngeal nerve (RLN) is a very reliable method. Method. The characteristics of the surgical anatomy of 1023 RLN have been summarized on the basis of intraoperative palpability, running down, branching variations, thickness, and laryngeal entry site. Results. Palpation was helpful in 81.4% (833/1023), proved false positive in 8.2% (84/1023), and in 10.4% (106/1023) it was of no help in the exact localization. Definitive RLN palsy was experienced in 0.78% of all cases (8/1023), while transient paresis was encountered in 1.2% (12/1023). Only a moderately strong stochastic correlation could be found between RLN palsies and those nerves which were nonpalpable and atypical, which showed the joint occurrence of being both thinner than normal and branching already before the plane of the inferior thyroid artery (Cramer's associate coefficient, C = 0.383). Conclusion. Palpation alone cannot substitute visualization and proper surgical dissection of the nerve. © 2008 Wiley Periodicals, Inc. Head Neck, 2009 [source] Benign parathyroid cyst causing vocal fold paralysis: A case report and review of the literatureHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 6 2006Daniel H. Coelho MD Abstract Background. Parathyroid cysts are uncommon, frequently asymptomatic lesions of the neck and superior mediastinum. Symptomatic parathyroid cysts are very rare, with roughly only 200 cases reported in the literature. Of these, only nine cases have been reported with recurrent laryngeal nerve (RLN) paralysis Methods. We report a case of a 49-year-old man initially seen with a 6-month history of worsening hoarseness. Physical examination revealed a palpable 3-cm, firm, smooth, nontender mass of the right thyroid lobe. Fiberoscopic laryngoscopy showed right vocal cord immobility consistent with RLN paralysis. After CT and fine-needle aspiration of the mass, the patient underwent a right thyroid lobectomy. During surgery, the recurrent laryngeal nerve was found to be stretched and adherent to a right inferior lobe mass. Results. Histologic analysis of the surgical specimen revealed a benign parathyroid adenomatous cyst. Postoperatively, the patient's voice improved markedly. This case represents an extremely rare return of function of the RLN after cyst removal. Conclusion. Parathyroid cysts should be included in the differential diagnosis for vocal fold paralysis. © 2006 Wiley Periodicals, Inc. Head Neck 28:564,566, 2006 [source] Transcricothyroid electromyographic monitoring of the recurrent laryngeal nerve,,THE LARYNGOSCOPE, Issue 10 2009Eran E. Alon MD Abstract Objectives/Hypothesis: To determine the usefulness of intraoperative nerve monitoring using an electrode placed in the midline through the cricothyroid membrane. Study Design: Retrospective records review. Methods: Patients of the otolaryngology department of our tertiary care academic medical center were identified if they had undergone either total thyroidectomy or total thyroid lobectomy accompanied by bilateral electromyographic (EMG) monitoring of the recurrent laryngeal nerve (RLN) between January 2007 and October 2007. Results: Forty-three patients were identified who had a total throidectomy or a total thyroid lobectomy. Nineteen of the 43 had intraoperative EMG monitoring of the RLN with placement of a single EMG electrode through the cricothyroid membrane; 11 had a thyroidectomy, and eight had a thyroid lobectomy. Overall, 30 at-risk nerves were stimulated with an EMG probe; 27 responded adequately and three (paralyzed before surgery) were unresponsive. Conclusions: Central placement of an EMG electrode through the cricothyroid membrane into the thyroarytenoid musculature is a safe and reliable technique for bilateral monitoring of the RLN that facilitates evaluation of postoperative function. Laryngoscope, 2009 [source] Quantitative Assessment of Laryngeal Muscle Morphology After Recurrent Laryngeal Nerve Injury: Right vs.THE LARYNGOSCOPE, Issue 10 2008Left Differences Abstract Objectives/Hypothesis: Reports of laryngeal response to denervation are inconsistent. Some document atrophy and fibrosis in denervated laryngeal muscles, whereas others indicate resistance to atrophy. Spontaneous reinnervation has also been documented. The goal of this study was to clarify the effects of nerve injury and reinnervation on thyroarytenoid (TA) and posterior cricoarytenoid (PCA) muscles. Study Design: Laboratory experiment. Methods: TA and PCA muscles of cats were harvested 5 to 6 months after transecting right or left recurrent laryngeal nerve (RLN). Images of muscle cross-sections were acquired and studied using an image analysis workstation. Cross-sectional areas as well as total cross-sectional area of randomly selected muscle fibers were recorded. Results: TA reinnervation was robust on both sides, but there was less reinnervation of the PCA muscle after left-sided RLN lesion than after right-sided injury. Conclusions: Differences in reinnervation after RLN injury could contribute to the higher clinical incidence of left- vs. right-sided laryngeal paralysis. [source] Optimization of Autologous Muscle Stem Cell Survival in the Denervated Hemilarynx,THE LARYNGOSCOPE, Issue 7 2008Stacey L. Halum MD Abstract Objective: Current treatments for vocal fold paralysis are suboptimal in that they fail to restore dynamic function. Autologous muscle stem cell (MSC) therapy is a promising potential therapy for vocal fold paralysis in that it can attenuate denervation-induced muscle atrophy and provide a vehicle for delivery of neurotrophic factors, thereby potentially selectively guiding reinnervation. The goal of this project was to characterize optimal conditions for injected autologous MSC survival in the thyroarytenoid (TA) muscle following recurrent laryngeal nerve (RLN) injury by local administration of adjuvant factors. Study Design: Animal experiment. Methods: Unilateral RLN transection and sternocleidomastoid muscle (,1 g) biopsies were performed in 20 male Wistar rats. One month later, 106 autologous MSCs labeled via retroviral-enhanced green fluorescent protein (EGFP) transduction were injected into the denervated hemilarynx of each animal with one of four adjuvant therapies: cardiotoxin [(CTX) 10,5 M], insulin-like growth factor-1 [(IGF- 1) 100 ,g/mL], ciliary neurotrophic factor [(CNTF) 50 ,g/mL], or saline. Animals were euthanized 1 month later and larynges harvested, sectioned, and analyzed for MSC survival. Results: All specimens demonstrate extensive MSC survival, with fusion of the MSCs with the denervated myofibers. Based on mean fluorescent intensity of the laryngeal specimens, IGF-1 and CNTF had the greatest positive influence on MSC survival. Myofiber diameters demonstrated myofiber atrophy to be inversely related to MSC survival, with the least atrophy in the groups having the greatest MSC survival. Conclusions: Autologous MSC therapy may be a future treatment for vocal fold paralysis. These findings support a model whereby MSCs genetically engineered to secrete CNTF and/or IGF-1 may not only promote neural regeneration, but also enhance MSC survival in an autocrine fashion. [source] A Novel Drug Therapy for Recurrent Laryngeal Nerve Injury Using T-588,THE LARYNGOSCOPE, Issue 7 2007Yuko Mori MD Abstract Objectives/Hypothesis: We have previously shown that gene therapy using Insulin-like growth factor (IGF)-I, glial cell line-derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF), or a combination of these trophic factors, is a treatment option for recurrent laryngeal nerve (RLN) palsy. However, there remain some difficulties preventing this option from becoming a common clinical therapy for RLN injury. Thus, we need to develop novel treatment option that overcomes the problems of gene therapy. R(,)-1-(benzothiophen-5-yl)-2-[2-N,N-diethylamino]ethoxy]ethanol hydrochloride (T-588), a synthetic compound, is known to have neuroprotective effects on neural cells. In the present study, the possibility of new drug treatments using T-588 for RLN injury was assessed using rat models. Study Design: Animal study. Methods: Animals were administered T-588 for 4 weeks. The neuroprotective effects of T-588 administration after vagal nerve avulsion and neurofunctional recovery after recurrent laryngeal nerve crush were studied using motoneuron cell counting, evaluation of choline acetyltransferase immunoreactivity, the electrophysiologic examination, and the re-mobilization of the vocal fold. Results: T-588 administration successfully prevented motoneuron loss and ameliorated the choline acetyltransferase immunoreactivity in the ipsilateral nucleus ambiguus after vagal nerve avulsion. Significant improvements of motor nerve conduction velocity of the RLN and vocal fold movement were observed in the treatment group when compared to controls. Conclusion: These results indicate that oral administration of T-588 might be a promising therapeutic option in treating peripheral nerve injury. [source] Ultrasonic Technology Facilitates Minimal Access Thyroid Surgery,THE LARYNGOSCOPE, Issue 6 2006David J. Terris MD Abstract Objectives: Options for controlling the vasculature during thyroid surgery include suture ligatures, vessel clips, and bipolar cautery. Ultrasonic technology represents an alternative to conventional techniques in which the vessels are simultaneously sealed and divided. We sought to determine the safety and efficacy of thyroidectomy with ultrasonic technology. Design: Nonrandomized, prospective analysis of a series of patients undergoing thyroidectomy at the Medical College of Georgia. Methods and Materials: The records of 51 consecutive patients who underwent thyroid surgery between December 2004 and June 2005 were reviewed. Patients in whom ultrasonic technology (Harmonic-ACEÔ, Ethicon Endo-Surgery, Cincinnati, OH) was used comprised the study population. Results: Forty-four of 51 patients underwent thyroidectomy with the assistance of ultrasonic technology. There were 4 males and 40 females with a mean age of 43.5 ± 15.8 years. Twenty-two patients had a total thyroidectomy, 18 underwent unilateral lobectomy, and 4 underwent completion thyroidectomy. The overall mean incision length was 5.0 ± 2.6 (range 2,12) cm. A subgroup of patients underwent minimally invasive video-assisted thyroidectomy (n = 13) and had a mean incision length of 29.3 ± 0.8 mm. There were no cases of permanent injury to the recurrent laryngeal nerve and no cases of persistent hypoparathyroidism. Blood loss ranged from 5 mL to 100 mL, with a mean of 26.7 ± 21.8 mL. Conclusions: Ultrasonic technology facilitates thyroid surgery, particularly when a minimally invasive approach is undertaken. It reliably seals and divides the thyroid vasculature and will likely replace other methods of managing the thyroid blood supply. [source] A Quantitative Study of the Medial Surface Dynamics of an In Vivo Canine Vocal Fold during Phonation,THE LARYNGOSCOPE, Issue 9 2005Michael Doellinger PhD Abstract Objectives/Hypothesis: The purpose of this study was to measure the medial surface dynamics of a canine vocal fold during phonation. In particular, displacements, velocities, accelerations, and relative phase velocities of vocal fold fleshpoints were reported across the entire medial surface. Although the medial surface dynamics have a profound influence on voice production, such data are rare because of the inaccessibility of the vocal folds. Study Design: Medial surface dynamics were investigated during both normal and fry-like phonation as a function of innervation to the recurrent laryngeal nerve for conditions of constant glottal airflow. Methods: An in vivo canine model was used. The larynx was dissected similar to methods described in previous excised hemilarynx experiments. Phonation was induced with artificial airflow and innervation to the recurrent laryngeal nerve. The recordings were obtained using a high-speed digital imaging system. Three dimensional coordinates were computed for fleshpoints along the entire medial surface. The trajectories of the fleshpoints were preprocessed using the method of Empirical Eigenfunctions. Results: Although considerable variability existed within the data, in general, the medial-lateral displacements and vertical displacements of the vocal fold fleshpoints were large compared with anterior-posterior displacements. For both normal and fry-like phonation, the largest displacements and velocities were concentrated in the upper medial portion. During normal phonation, the mucosal wave propagated primarily in a vertical direction. Above a certain threshold of subglottal pressure (or stimulation to the recurrent laryngeal nerve), an abrupt transition from chest-like to fry-like phonation was observed. Conclusions: The study reports unique, quantitative data regarding the medial surface dynamics of an in vivo canine vocal fold during phonation, capturing both chest-like and fry-like vibration patterns. These data quantify a complex set of dynamics. The mathematical modeling of such complexity is still in its infancy and requires quantitative data of this nature for development, validation, and testing. [source] Delivery of an Adenoviral Vector to the Crushed Recurrent Laryngeal Nerve,THE LARYNGOSCOPE, Issue 6 2003Adam Rubin MD Abstract Objectives Objectives were to create a model of recurrent laryngeal nerve injury for testing the efficacy of potential therapeutic viral gene therapy vectors and to demonstrate that remote injection of a viral vector does not cause significant additional neuronal injury. Study Design Animal model. Methods Rats were randomly assigned to three groups of 10 animals each. In group I, the recurrent laryngeal nerve was crushed. In group II, the nerve was crushed and then injected with an adenoviral vector containing no transgene. In group III, the nerve was identified but was not crushed. Rats were killed at 1 week, and their larynges and brainstems were cryosectioned in 15-,m sections. Laryngeal cryosections were processed for acetylcholine histochemical analysis (motor endplates) followed by neurofilament immunoperoxidase (nerve fibers). Percentage of nerve,endplate contact was determined and compared between groups. Fluorescent in situ hybridization was performed on brainstem sections from rats in group II to confirm the presence of virus. Results No significant difference in percentage of nerve,endplate contact exists between the two crushed-nerve groups (groups I and II) (P = .88). The difference between both crushed-nerve groups and the group with noncrushed nerves (group III) was highly significant (P <.0001). The presence of virus was confirmed in group II rats. Conclusions Crush provides a significant measurable injury to the recurrent laryngeal nerve and may be used as a model to explore therapeutic interventions for nerve injury. The remote injection of viral vector did not cause significant additional neuronal injury. Remote delivery of viral vectors to the central nervous system holds promise in the treatment of recurrent laryngeal nerve injury and central nervous system diseases. [source] Safety of Completion Thyroidectomy Following Unilateral Lobectomy for Well-Differentiated Thyroid Cancer,THE LARYNGOSCOPE, Issue 7 2002Michael E. Kupferman MD Abstract Objectives When a diagnosis of thyroid cancer is returned following unilateral lobectomy, removal of the contralateral lobe is frequently necessary. Morbidity for completion thyroidectomy includes a reported 2% to 5% risk of recurrent laryngeal nerve (RLN) injury and an 8% to 15% incidence of hypoparathyroidism. In this study, to determine morbidity following completion thyroidectomy, we reviewed our results of reoperative surgery among patients with thyroid cancer. Study Design Retrospective chart review. Methods Between 1997 and 2000, 36 consecutive patients, 32 females and 4 males, with a mean age of 43.6 years (range, 19,59 y), underwent completion thyroidectomy. Preoperative fine-needle aspiration revealed follicular derived neoplasm in 32 patients (88.9%), indeterminate in 3 patients (8.3%), and Hürthle cell neoplasm in 1 patient (2.8%). The interval between the first and second operation was a mean of 43.3 days (range, 2,103 d). Results At the primary surgery, 29 patients (80.6%) had a follicular variant of papillary carcinoma, 6 (16.7%) had follicular carcinoma, and 1 (2.8%) had Hürthle cell carcinoma. Of these, 14 had multifocal disease. In the completion lobe, 20 patients (55.6%) had evidence of thyroid carcinoma. There was a 0% incidence of RLN injury, and the mean pre- and post-completion thyroidectomy serum calcium was 8.9 mg/dL and 8.6 mg/dL, respectively. There was one postoperative hematoma, requiring re-exploration. Five patients (13.9%) had a transient postoperative serum calcium (Ca) <8.0 mg/dL, with one being symptomatic. None required vitamin D or prolonged calcium supplementation. Conclusions When completion thyroidectomy is necessary for the treatment of thyroid malignancy, the procedure can be performed safely with low morbidity and is effective for diagnosing and removing occult disease in the remaining thyroid. [source] Morphologic Correlates for Laryngeal Reinnervation,THE LARYNGOSCOPE, Issue 11 2001Richard R. Gacek MD Abstract Objective To describe morphologic correlates for laryngeal reinnervation. Study Design Review of anatomic experiments dealing with laryngeal innervation performed over a 25-year period. Methods Description of results from experimental studies on the cat and human laryngeal muscles and nerve supply. Results Despite separation of abductor and adductor laryngeal motor neurons in the central nervous system, the mixture of abductor and adductor axons in the recurrent laryngeal nerve indicates that selective re-innervation of an individual laryngeal muscle must be accomplished at the neuromuscular junction (NMJ) of the muscle. The optimal time for a reinnervating neural source to re-occupy vacated NMJ is at the time of denervation. If the reinnervation procedure is attempted long (>1 mo) after denervation, extraneous end plates of other neural systems must be eliminated to provide vacant NMJ. The nerve muscle pedicle (NMP) concept is an effective model for reinnervation of a laryngeal muscle provided its activity pattern is similar to that of the denervated muscle and its insertion into vacated NMJ is timely. Conclusion NMP offers a logical method for selective laryngeal muscle reinnervation. Critical to the success of NMP are the physiological input to the NMP and timing of NMP implantation. [source] Expression of Fibroblast Growth Factor-2 in the Nucleus Ambiguus Following Recurrent Laryngeal Nerve Injury in the RatTHE LARYNGOSCOPE, Issue 12 2000Tetsuji Sanuki MD Abstract Objectives To examine fibroblast growth factor-2 (FGF-2) immunoreactivity in the nucleus ambiguus (NA) after three different recurrent laryngeal nerve (RLN) injuries. Study Design Immunohistochemical analysis of FGF-2. Methods Thirty adult rats underwent left-sided RLN crush (group A). The left RLN was transected in groups B (n = 30) and C (n = 30); in group C, both nerve stumps were covered with silicone caps. FGF-2 in the NA was assessed as the ratio of the positive areas on the left (operated [O]) and right (unoperated [U]) sides. The ratio (O/U) was measured 1, 3, 7, 14, and 28 days after the procedure. Three rats underwent left-sided RLN exposure and were killed 7 days later (control). Results Left-sided RLN paralysis occurred until day 28 in group A. In the control group, O/U was approximately 1. In group A, O/U was significantly elevated on day 7; in group B, on days 3, 7, and 14; and in group C, on day 3. O/U in group B was significantly greater than that in group A on days 14 and 28. Maximal FGF-2 immunoreactivity was significantly lower in group C than in groups A and B. Conclusions We demonstrated elevated production of FGF-2 in the NA after RLN injury. This endogenous FGF-2 might contribute to preventing lesion-induced neuronal death. Blockage of axonal regeneration might suppress FGF-2 production in the NA. Further understanding of the roles of FGF-2 after RLN in-jury may contribute to the prevention of neuronal death and facilitation of axonal regeneration. [source] Vocal Fold Paralysis After Anterior Cervical Spine Surgery: Incidence, Mechanism, and Prevention of Injury,THE LARYNGOSCOPE, Issue 9 2000Mark D. Kriskovich MD Abstract Objective Vocal fold paralysis is the most common otolaryngological complication after anterior cervical spine surgery (ACSS). However, the frequency and etiology of this injury are not clearly defined. This study was performed to establish the incidence and mechanism of vocal fold paralysis in ACSS and to determine whether controlling for endotracheal tube/laryngeal wall interactions induced by the cervical retraction system could decrease the rate of paralysis. Study Design Retrospective review and complementary cadaver dissection. Methods Data gathered on 900 consecutive patients undergoing ACSS were reviewed for complications and procedural risk factors. After the first 250 cases an intervention consisting of monitoring of endotracheal tube cuff pressure and release of pressure after retractor placement or repositioning was employed. This allowed the endotracheal tube to re-center within the larynx. In addition, anterior approaches to the cervical spine were performed on fresh, intubated cadavers and studied with videofluoroscopy following retractor placement. Results Thirty cases of vocal fold paralysis consistent with recurrent laryngeal nerve injury were identified with three patients having permanent paralysis. With this technique temporary paralysis rates decreased from 6.4% to 1.69% (P = .0002). The cadaver studies confirmed that the retractor displaced the larynx against the shaft of the endotracheal tube with impingement on the vulnerable intralaryngeal segment of the recurrent laryngeal nerve. Conclusion The study results suggest that the most common cause of vocal fold paralysis after anterior cervical spine surgery is compression of the recurrent laryngeal nerve within the endolarynx. Endotracheal tube cuff pressure monitoring and release after retractor placement may prevent injury to the recurrent laryngeal nerve during anterior cervical spine surgery. [source] NERVE STIMULATION IN THYROID SURGERY: IS IT REALLY USEFUL?ANZ JOURNAL OF SURGERY, Issue 5 2007Thorbjorn J Loch-Wilkinson Background: Monitoring of the recurrent laryngeal nerve (RLN) has been claimed in some studies to reduce rates of nerve injury during thyroid surgery compared with anatomical dissection and visual identification of the RLN alone, whereas other studies have found no benefit. Continuous monitoring with endotracheal electrodes is expensive whereas discontinuous monitoring by laryngeal palpation with nerve stimulation is a simple and inexpensive technique. This study aimed to assess the value of nerve stimulation with laryngeal palpation as a means of identifying and assessing the function of the RLN and external branch of the superior laryngeal nerve (EBSLN) during thyroid surgery. Methods: This was a prospective case series comprising 50 consecutive patients undergoing total thyroidectomy providing 100 RLN and 100 EBSLN for examination. All patients underwent preoperative and postoperative vocal cord and voice assessment by an independent ear, nose and throat surgeon, laryngeal examination at extubation and all were asked to complete a postoperative dysphagia score sheet. Dysphagia scores in the study group were compared with a control group (n = 20) undergoing total thyroidectomy without nerve stimulation. Results: One hundred of 100 (100%) RLN were located without the use of the nerve stimulator. A negative twitch response occurred in seven (7%) RLN stimulated (two bilateral, three unilateral). Postoperative testing, however, only showed one true unilateral RLN palsy postoperatively (1%), which recovered in 7 weeks giving six false-positive and one true-positive results. Eighty-six of 100 (86%) EBSLN were located without the nerve stimulator. Thirteen of 100 (13%) EBSLN could not be identified and 1 of 100 (1%) was located with the use of the nerve stimulator. Fourteen per cent of EBSLN showed no cricothyroid twitch on EBSLN stimulation. Postoperative vocal function in these patients was normal. There were no instances of equipment malfunction. Dysphagia scores did not differ significantly between the study and control groups. Conclusion: Use of a nerve stimulator did not aid in anatomical dissection of the RLN and was useful in identifying only one EBSLN. Discontinuous nerve monitoring by stimulation during total thyroidectomy confers no obvious benefit for the experienced surgeon in nerve identification, functional testing or injury prevention. [source] Total versus subtotal thyroidectomy for the management of benign multinodular goiter in an endemic regionANZ JOURNAL OF SURGERY, Issue 11 2004Tahsin Colak Background: Because controversy still continuous to surround use of total thyroidectomy for the management of benign multinodular goiter, the present study aims to prospectively compare the safety and efficacy of total thyroidectomy with subtotal thyroidectomy. Methods: A total of 200 consecutive patients with benign multinodular goiter were assigned to have either total thyroidectomy (n = 105) or subtotal thyroidectomy (n = 95) based on preoperative evaluation, intraoperative macroscopic findings and nodular dissemination. The patients with no healthy tissue or nodules localized in the dorsal part of the gland, which are usually left during normal subtotal resection, were assigned to the total thyroidectomy group. Demographic details, biochemical findings, indications for operation, operating time, specimen weight, complications and hospital stay were noted. Results: There was no significant difference in the sex, hormonal status or duration of goiter between the two groups (P = 0.74, P = 0.59 and P = 0.59, respectively). The mean operating time was longer (148.52 min ± 51.10 vs 135.10 min ± 32.47, P = 0.03), and the mean weight of the specimens was greater (228.40 g ± 229.91 vs 157.01 g ± 151.23, P = 0.01) for total rather than subtotal thyroidectomy. Either temporary recurrent laryngeal nerve (RLN) palsy or hypoparathyroidism occurred in 10 (9.3%) or 12 (11.4%) of the patients undergoing total compared with six (6.3%) or nine (9.5%) of the patients undergoing subtotal thyroidectomy (P = 0.40 and P = 0.65, respectively). Either permanent RLN palsy or hypoparathyroidism was observed in one patient undergoing total thyroidectomy (P = 0.34 for each comparison). The mean hospital stay was longer in the total thyroidectomy group (2.24 days ± 1.18 vs 1.89 days ± 0.72 for subtotal thyroidectomy, P = 0.01). Conclusions: The present study shows that total thyroidectomy can be performed without increasing risk of complication, and it is an acceptable alternative for benign multinodular goiter, especially in endemic regions, where patients present with a huge multinodular goiter. [source] An unusual course of the left recurrent laryngeal nerveCLINICAL ANATOMY, Issue 3 2007Amir A. Khaki Abstract Variation in the course of the left recurrent laryngeal nerve is seemingly very rare. During the routine dissection of an adult male cadaver, the entire left recurrent laryngeal nerve after branching from the left vagus nerve was noted to travel medial to the ligamentum arteriosum. We hypothesize that this rare variation may occur, if the left recurrent laryngeal nerve passes inferior to the fifth rather than the sixth aortic arch during embryological development. As our case report demonstrates, the relationship between the ligamentum arteriosum and the left recurrent laryngeal nerve is not absolute. Although seemingly rare, cardiothoracic surgeons must consider variations of the left recurrent laryngeal nerve during surgical procedures in the region of the ligamentum arteriosum in order to minimize potential postoperative complications. Clin. Anat. 20:344,346, 2007. © 2006 Wiley-Liss, Inc. [source] Predictive factors for recurrent laryngeal nerve palsy and hypoparathyroidism after thyroid surgeryCLINICAL OTOLARYNGOLOGY, Issue 1 2007Y. Erbil Objectives:, To evaluate the incidence and risk factors of recurrent laryngeal nerve palsy and hypoparathyroidism following thyroidectomy. Design:, Retrospective case,control study. Setting:, Tertiary clinic. Participants:, From September 1990 to September 2005, 3250 consecutive patients who had a thyroidectomy for treatment of various thyroid diseases. Main outcome measures:, The rates of nerve palsy and hypoparathyroidism were evaluated based on thyroid pathology, the choice of operative procedure, whether the nerve was identified, and the experience of the surgeon. Results:, Overall, the rate of nerve palsy was 1.8% and that of hypoparathyroidism was 6.6%. On univariate analysis the rates of complications were siginificantly higher in the patients who had an extended thyroidectomy, identification of the recurrent laryngeal nerve during surgery, repeat surgery and patients older than 50 years of age. Complications were no commoner in operations performed by trainees under supervision than experienced surgeons. On multivariate analysis extended thyroidectomy had a 12 fold (95% CI 1.7, 92) increased risk of nerve palsy. Repeat surgery had a 3 fold (95% CI 2.1, 4.7) increased risk of postoperative hypoparathyroidism. Conclusion:, Extentended thyroidectomy and repeat surgery had a significant effect on the incidence of recurrent laryngeal nerve palsy and postoperative hyperparathyroidism respectively following thyroid surgery. [source] CO2 laser treatment of Zenker's diverticulaCLINICAL OTOLARYNGOLOGY, Issue 4 2001H.H.W. De Gier Introduction. Evaluation of the results of endoscopic CO2 laser treatment of Zenker's diverticula. Methods. The records of all patients treated in the University Hospital Rotterdam between 1990 and 1996 using CO2 laser surgery or electrocautery (when CO2 laser was impossible because of technical reasons) for a Zenker's diverticulum were studied. Results. One hundred and eighty-three patients were treated for a Zenker's diverticulum, 179 times using CO2 laser and 42 times using electrocautery. In 29 patients, two or more treatments were needed. Twenty-five complications occurred, five severe and 20 mild. One patient died and in one patient the recurrent laryngeal nerve was damaged; the other patients made full recoveries. Conclusion. CO2 laser surgery is a safe and effective method of treatment for Zenker's diverticula. [source] Artificial Manipulation of Voice in the Human by an Implanted StimulatorTHE LARYNGOSCOPE, Issue 10 2008FACS, Michael Broniatowski MD Abstract Objectives/Hypothesis: Traditional approaches influencing voice quality (e.g., anatomical and chemical denervation for spasmodic dysphonia, surgical medialization for paralysis) have ignored the dynamic nature of the larynx. Study Design: We report here the first attempt to manipulate voice using an implanted stimulator to systematically control vocal fold adduction. Methods: Devices placed for aspiration in three subjects retaining speech after stroke, cerebral palsy, and multiple sclerosis were used to stimulate recurrent laryngeal nerves with 42 Hz, 52 to 200 microsecond pulses of incremental amplitudes during phonation with the tracheostomy tube occluded. Vocal fold adduction increased with stimulation strength (P < .05). Speech was analyzed with the Vox Metria program. Results: We found highly significant differences for fundamental frequency (P < .007), jitter (P < .004), and shimmer (P < .005), between natural and stimulated voice (aah and eeh) when using higher charges. Conclusions: Dynamic vocal fold manipulation seems promising in terms of versatility lacking with static approaches to voice control. [source] Microsurgical Anatomy of the Laryngeal Nerves as Related to Thyroid SurgeryTHE LARYNGOSCOPE, Issue 2 2002Ashkan Monfared BS Abstract Objectives The objectives were to explore microsurgical anatomy of the superior and recurrent laryngeal nerves and their importance in thyroid surgery, and to examine areas of potential morbidity, means of identification, and arterial supply of the laryngeal nerves. Study Design Descriptive analysis of anatomical features. Methods Twenty-one adult cadavers, some perfused with colored silicon, were dissected for the study project. Results The right recurrent laryngeal nerve (RLN) branches off the vagus at the level of the subclavian artery and the left one at the level of the aorta. Both ascend parallel to the tracheoesophageal groove and innervate trachea, esophagus, and the inferior pharyngeal constrictors en route. The RLN has the highest probability to pass between the branches of the inferior thyroid artery on the right side and posterior to them on the left side. The RLN always passes posterior to the cricothyroid joint. The RLN is supplied by the branches of the inferior thyroid artery. The superior laryngeal nerve (SLN) branches into internal and external branches deep to the carotid bifurcation. The internal branch passes deep to the superior thyroid artery and descends toward thyrohyoid membrane. The external branch travels deep and parallel to the superior thyroid artery to innervate cricothyroid muscle. The internal branch is supplied by the superior laryngeal artery, and the external branch by the cricothyroid artery. Conclusions The only consistent location of the RLN is when it passes posterior to the cricothyroid joint. Because of extreme variability of the inferior thyroid artery and the RLN, it is suggested that the artery be ligated either proximally or at its tertiary branches on thyroid capsule. The internal branch of the SLN is not potentially at risk during thyroidectomy unless the superior thyroid artery is ligated proximally. The external branch of the SLN accompanies the superior thyroid artery for most of its course and is at potential risk if the trunk of the superior thyroid artery is ligated outside the pretracheal fascia. [source] Quality monitoring in thyroid surgery using the Shewhart control chart,BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 2 2009A. Duclos Background: A control chart can help to interpret and reduce sources of variability in patient safety by continuously monitoring indicators. The aim of this study was to monitor the outcome of thyroid surgery using control charts. Methods: Patients who had thyroid surgery during 2006,2007 were included in the study. Safety was monitored based on postoperative complications of recurrent laryngeal nerve palsy and hypocalcaemia. Indicators were extracted prospectively from the hospital information system and plotted each month on a P-control chart. Performance of the surgical team was also measured retrospectively for 2004,2005 (baseline period) to compare surgical outcomes before and after control chart implementation. Electromyographic monitoring of recurrent laryngeal nerves was not used, nor was calcium or vitamin D given routinely. Results: The outcomes of 1114 thyroid procedures were monitored. Although the proportion of patients with recurrent laryngeal nerve palsy was similar for baseline and monitored periods (6·4 and 7·2 per cent respectively), there was a 35·3 per cent decrease in hypocalcaemia after implementation of control charts (P < 0·001). Complications almost doubled during a period when one surgeon was away and operating room renovations took place. Conclusion: Outcome monitoring in thyroid surgery using control charts is useful for identifying potential issues in patient safety. Copyright © 2009 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||