Recurrent laryngeal nerve paralysis after thyroid gland operations. Etiology and consequences]

In the period of 1 January 1990 to 31 December 1996 the thyroidectomy cases we performed were immediately followed by vocal cord evaluation using a flexible bronchoscope while the patient was still on the operating table. If an obvious cord paralysis was discovered, an exploration of the recurrent laryngeal nerve, to the level of the larynx, was performed. If the nerve was found to be intact, no further measures were taken. A severed nerve underwent suture repair. If an otolaryngologist diagnosed a vocal cord paralysis 1-5 days after surgery, a reoperation was recommended except in the cases where postoperative bronchoscopy had shown an easily mobile cord or the recurrent nerve was completely dissected during the operation. Within this 7-year period, we performed 3492 thyroidectomy operations. The diagnosis of subsequent unilateral postoperative vocal cord paralysis occurred in 48 cases. In 33 of these cases the status of the nerve in the surgical field was known: 4 patients had an intact nerve proved by complete dissection during thyroidectomy, in two patients the lesions of the nerve were detected intraoperatively (1 transsection, 1 partial resection), and 27 cases were followed by reoperation. Of the 33 patients mentioned above, in 19 instances the recurrent laryngeal nerve was found to be intact; 3 displayed signs of local trauma, and 11 were found to be severed with total discontinuity. Those patients with an intact nerve, or local nerve trauma only, went on to develop normal function within 6 months in 20 (91%) of 22 cases. Of the 11 with a severed nerve, 8 showed "autoparalysis" with good voice within 4-8 months, after suture repair in 10 cases. The patient with partial resection had no repair of the nerve. If immediate postoperative evaluation showed mobility of the vocal cords but a paralysis was detected later by an otolaryngologist and repeat intervention was not done, vocal cord function was spontaneously restored in 9 of 11 patients. Four patients refused reoperation. From 1990 to 1991, the recurrent laryngeal nerve was not always dissected during our thyroidectomy operations. However, this was done routinely from 1991 to 1996. Routine intraoperative dissection of the vocal cord nerve reduced the rate of postoperative cord paralysis from 2.0% to 1.2%. It also reduced the frequency of intraoperative nerve injury with total discontinuity from 0.58% to 0.23%.     

Medialization laryngoplasty

Medialization laryngoplasty was performed in 25 patients between 1993 and 1997. The underlying pathology resulting in glottal incompetence was vocal cord paralysis in 22 patients and vocal cord bowing in 3 patients. Two types of implants were used: self-carved Proplast in 19 patients and prefabricated hydroxyapatite prostheses in 6 patients. Preoperative and postoperative results were compared in terms of dysphagia, vocal quality as graded by three experienced voice specialists, and computer measurements of the glottal gap. All patients showed improvement both subjectively and on the objective measurements used. Swallowing returned to normal in all patients who had isolated recurrent laryngeal nerve paralysis. The voice improved in all patients but was rarely judged as entirely normal.     

An endolaryngeal method of vertico-lateral transposition of the vocal cord for bilateral abductor paralysis

An endolaryngeal method of vertico-lateral elevation and fixation of the vocal fold in the treatment of bilateral recurrent laryngeal nerve paralysis is described. In 62 patients on whom this operative procedure was performed, a considerable improvement in respiration at the same time as almost unchanged phonation has been obtained in 61 cases. The results are illustrated by sonograms and respirometric examinations. Laryngograms demonstrate the function of the newly created glottis.     

Vowel-related differences in laryngeal articulatory and phonatory function

The purpose of this investigation was to study the interaction between the supralaryngeal and laryngeal components of the speech mechanism by examining vowel-related effects for a variety of vocal fold articulatory and phonatory measures. Secondary issues were to determine if vowel-related differences were influenced by the nature of the speaking task or gender. Between-vowel differences in estimated subglottal air pressure, peak oral air flow, mean phonatory air flow, air flow near the termination of the vowel, electroglottograph cycle width (EGGW), fundamental frequency, and voice onset time were examined for men and women during syllable repetitions and sentence productions. Significant vowel-related differences were found for all of the measures except mean phonatory air flow, and generally were not influenced by speaking task or gender. Vowel-related effects for estimated subglottal air pressure, peak oral air flow, fundamental frequency, and VOT were consistent with some earlier studies. New findings included vowel-related differences in EGGW and air flow near the termination of the vowel. We propose a model that includes the contribution of mechanical forces, reflexive neural activity, and learned neural activity to explain vowel-related effects. When vowel height is varied, changes in laryngeal cartilage positioning and vocal fold and vocal tract tension appear to influence laryngeal articulatory and phonatory function.     

A girl with transient psychological disturbance caused by orally administered acyclovir--differentiation between acyclovir neurotoxicity and herpes simplex encephalitis

To describe a simple technique for identifying the recurrent laryngeal nerve (RLN) with a nerve stimulator to prevent damage to the nerve during thyroid surgery. A retrospective review of 70 thyroidectomies performed from October 1989 to January 1995 by one surgeon using electrophysiologic nerve stimulation to identify the RLN was conducted. The technique is described. Outpatient flexible fiberoptic laryngoscopy was performed preoperatively and postoperatively in all patients. From 70 thyroidectomies, 80 RLNs were identified to be at risk for injury. Five patients had transient unilateral vocal cord paresis postoperatively. No RLN transection or permanent vocal cord paralysis occurred. This is the first large series of patients undergoing the use of electrophysiologic nerve stimulation for identifying the RLN during thyroid surgery. We found the technique to be useful and safe for identifying the RLN. We present this technique as a less costly and time-consuming alternative to intraoperative RLN monitoring.     

A case of mediastinal cystic hygroma whose only symptom was hoarseness

Hoarseness caused by mediastinal cystic hygroma has not been reported before. The authors report a case of mediastinal cystic hygroma in which the patient's only symptom was hoarseness. A 6-year-old girl had hoarseness. Physical examination findings were normal except for indirect laryngoscopy, which showed unilateral vocal cord paralysis. The chest radiograph showed an opacification 3 cm wide in the left side of the superior mediastinum. Through a median sternotomy, a large multicystic mass was resected. During resection, left laryngeal recurrent nerve was seen to be intact, and its integrity was preserved. Six months later the left vocal cord was moving to a limited extent. A chest radiograph should be considered in a case of hoarseness caused by a peripheral nerve lesion to detect a mediastinal mass without any cervical component.     

Anterior-posterior and medial compression of the supraglottis: signs of nonorganic dysphonia or normal postures?

Two vocal tract postures commonly identified as hallmarks of nonorganic dysphonia are anterior-posterior and medial compression of the supraglottis. However, insufficient data exist to support their diagnostic utility. The purpose of this study was to compare these two postures in patients with nonorganic dysphonia and normal controls using interval data derived from quantitative measures of videostroboscopic images obtained with an oral endoscope. Retrospectively, 40 patients with nonorganic dysphonia and 40 normal controls were selected. Relative anterior-posterior compression (LO(AP)) was calculated as the laryngeal outlet (LO) (the view of the true vocal folds during phonation) normalized to the anterior-posterior dimension in pixels. Relative ventricular fold medial compression (LO(w)) was calculated as the laryngeal outlet normalized to the medial dimension in pixels. Results were as follows: (1) LO(AP) was significantly greater for the dysphonic group, (2) the range of LO(AP) values between the two groups overlapped considerably, (3) no significant difference was found between groups for LO(w), (4) the correlation between LO(AP) and LO(w) within each subject yielded r values of 0.71 and 0.67 for the nonorganic dysphonia and normal control groups, respectively. It is concluded that medial compression of the ventricular folds can be a normal laryngeal posture, and that although anterior-posterior compression is present in greater degree in dysphonics, it is sufficiently common in normals to question its utility as a diagnostic sign of phonatory dysfunction.     

Endolaryngeal surgical procedures in glottis expansion in bilateral recurrent nerve paralysis

OBJECTIVE: Subtotal cordectomy and posterior cordectomy have repeatedly been recommended as surgical interventions restoring the airway, for the treatment of bilateral vocal cord paralysis. The objective of this study was to assess the effectiveness of transoral laser cordectomy and posterior cordectomy as compared to laser arytenoidectomy and to compare the respiratory and phonatory results of these minimally invasive procedures. MATERIAL AND METHODS: Forty patients with bilateral vocal cord paralysis were included in a prospective study and operated upon to improve their laryngeal airways. Twenty-two patients had cordectomy, 13 had arytenoidectomy, and 5 had posterior cordectomy. Lung function tests and voice analysis were obtained preoperatively and postoperatively. Subclinical aspiration was determined by endoscopic evaluation of the larynx during deglutition. The results were compared to determine the relative effectiveness of the three surgical methods. RESULTS: Flow volume spirograms documented equally improved flow rates in both groups. Final voice evaluation revealed maximum phonation time. Peak sound pressure levels and frequency range were reduced in all 28 patients, but phonatory results varied considerably in each group. Subclinical aspiration was noticed in 5 out of 10 patients after arytenoidectomy, but in none of 18 patients after cordectomy. Four previously tracheotomised patients were decannulated within 2 weeks after surgery, while the other 24 patients had no perioperative tracheotomies. CONCLUSION: Transoral laser cordectomy and arytenoidectomy are equally effective and reliable in the management of the restricted airway. Cordectomy and posterior cordectomy offer the advantage of uncompromised deglutition after surgery. Although no clinically relevant aspiration occurred in any of the patients, cordectomy should be considered as the method of choice in patients for whom subclinical aspiration could be potentially harmful due to coexisting pulmonary or cardiac disease. Phonatory outcome is not predictable with both surgical procedures. Subtotal cordectomy and posterior cordectomy are easier and faster to perform, and subclinical aspiration is not encountered with these procedures.     

A preliminary study of the prognostic role of electromyography in laryngeal paralysis

Confidence in the reliability of laryngeal electromyography to predict recovery is critical if this tool is to be used to select the type and timing of surgical intervention. The characteristics of electromyography of 14 patients with unilateral vocal fold paralysis were assessed to determine which factor or combination of factors would be most useful in determining prognosis. We examined the duration, amplitude, waveform morphology, root-mean-square, and time interval from onset to electromyography recording. The results supported the concept that electromyography recordings are valuable in determining prognosis if performed before 6 months and preferably within 6 weeks of onset of laryngeal paralysis. A positive prognosis for laryngeal recovery was indicated when the following electromyography features were present in the immobile vocal fold: (1) normal motor unit waveform morphology, (2) overall electromyography activity characterized by a root-mean-square value greater than 40 microV in any one task, and (3) no electrical silence during voluntary tasks. On the basis of this criteria our overall correct prognostic rate was 89%.     

Phonosurgery of chronic vocal cord edema

INTRODUCTION: Chronic (Reinke's) oedema of the vocal folds is a frequent and declicate objective of phonosurgery. It is characterized by a marked bilateral subepithelial oedema, which develops by degrees, as a non-specific reaction of the vocal folds to various irritative noxious agents (especially smoking), in patients with some predisposition. It is found, by the light and electron microscopes and immunohistochemistry, that oedema is characterized by subepithelial fissure-like spaces, which accumulate a protein-rich fluid, and develops like neobursae. Therefore, mechanical factors and functional influences may also contribute to the development of Reinke's oedema. The voice is low pitched and with various degrees of hoarseness. Reinke's oedema alters the mechanical properties of the cover, which becomes very pliable and with reduced stiffness, incapacitating the vocal fold for production of high tones. Hoarseness is induced in subject with associated laryngitis, or disbalance in mechanical properties of the vocal folds. Hyperkinetic pattern of voice production can often be seen in patients with Reinke's oedema, which is a compensatory results of reduced functional capability of the vocal folds. Stroboscopy reveals a prolonged closed phase of the vibratory cycles and strikingly marked mucosal waves. MATERIAL AND METHOD: A series of 371 patients with Reinke's oedema was operated by direct microlaryngoscopy, under the general anaesthesia. The "excessive" mucosa was removed by bimanual micro-procedure, while the care was not taken to severe layers deeper than a superficial part of the intermediate layer of the vocal fold (Reinke's space). In this procedure we used the micro-forceps and scissors, to detach oedema parallel to the free edge of the vocal fold, at its upper and lower demarcation lines, beginning from the posterior part of oedema. Another 27 patients were operated by indirect procedures. Microstroboscopy (IMS) was used in subjects, while videostroboscopy (IVS) was carried out in another 18 patients. These procedures were used when general anaesthesia was contraindicated, and in patients with Reinke's oedema of the first degree (initial oedema). In these patients only a mucosal strip was removed from the upper surface of the vocal fold, apart from the free edge. Oedema was removed bilaterally, while the formation of the postoperative web was prevented by regular examinations of the patient. In several cases of adherence between the two folds in their anterior commissure, the problem was solved indirectly by the use of a curved forceps and under the topical anaesthesia. Postoperative voice rest and administration of steroids were mandatory. Surgical and functional results were followed-up by stroboscopy over the period of at least three years after surgery. The majority of patients were additionally treated by the voice therapy, while the decision about its use was made three weeks after surgery. RESULTS: Functional results of our therapeutic strategy were satisfactory in our series of 398 subjects with Reinke's oedema. In comparison with other benign lesions of the vocal folds, it was more time-consuming and required a more frequent use of the postoperative voice therapy (Table 1). Thus, we have not encountered recurrences. DISCUSSION: During the last 10 years we operated on 1550 patients with various benign lesions of the vocal folds, including 398 subjects with Reinke's oedema (25.7%). Excision of the "excessive" mucosa may appear today as a procedure which is too radical if compared with many techniques which have been offered during the last decades: conservative excision and suction, squeezing technique, laser. Nevertheless, the histological structure of Reinke's oedema, with subepithelial fissure-like spaces indicated that the latter procedures can hardly be expected to prevent recurrences. It was found that the use of laser was not favourable in this area for its deteriorative local effect.     

Laterofixation of the vocal cord by Ejnell's operation for bilateral vocal cord paralysis

In patients with bilateral vocal cord paralysis, several therapeutic techniques have been proposed to improve laryngeal obstruction. Since 1990, we have performed Ejnell's operation on six patients, one male and five females, suffering from bilateral vocal cord paralysis. Tracheostomy had been performed in four patients prior to their consultation. Five patients underwent a breathing capacity examination before and after the operation. Four of the patients showed improvement in breathing capacity and the tracheostoma was closed in those four patients. There was little aspiration problem during the postoperative follow-up period. Our experience suggests that Ejnell's operation is technically simple and should be useful in the treatment of bilateral vocal cord paralysis.     

Topology of the principal EEG elements of sleep analyzed by analogue filters

In order to compare the venodilation effect of morphine in normal individuals (22) with that in patients (13) with heart failure morphine sulfate (0.1 mg/kg) was administered to 13 patients with mild pulmonary edema. After morphine congestive symptoms improved and venodilation was induced as determined by two independent techniques: venous pressure fell 10.2 mm Hg by the isolated hand technique and the venous volume of the forearm increased by 0.48 cc/100 ml, measured by equilibration technique. Neither finding differed from those in normal individuals. Reflex venoconstriction noted on the taking of a single deep breath was unaffected by morphine administration and was similar to that observed in normal subjects. Since the drug morphine sulfate does not cause a major pooling of blood in the limbs, the favorable effect of narcotics in patients with pulmonary edema must be caused by other mechanisms such as splanchnic pooling, afterload reduction or reduced breathing effort.     

Vocal cord laterofixation as early treatment for acute bilateral abductor paralysis after thyroid surgery

Bilateral vocal cord palsy due to a lesion of the recurrent laryngeal nerves is a serious complication of thyroid operations, with the airway obstruction usually necessitating tracheostomy. In the cases presented, a stable airway was ensured with endolaryngeal cord laterofixation instead of tracheostomy. The operation was performed with the endo-extralaryngeal needle carrier instrument devised by Lichtenberger. During the operation, only minor surgical trauma occurred in the larynx. The fixing thread was then removed following recovery of contralateral vocal cord function, resulting in an improvement in the voice. Four patients are described who suffered bilateral recurrent laryngeal nerve palsy after thyroid gland operations. During the follow-up period of 3-12 months, airway stability was demonstrated by regular spirometric measurements. The simple method recommended spares patients the possible complications of tracheostomy.     

Ansa-recurrent nerve anastomosis for vocal cord paralysis due to mediastinal lesions

Recurrent laryngeal or vagus nerve injuries in the mediastinum are repaired rarely because of technical difficulties. Impairment in phonation is especially severe in patients with respiratory dysfunction. We performed a simple and less invasive reconstruction, ansa cervicalis-recurrent laryngeal nerve anastomosis in the neck, to improve phonation in 2 patients. Although the reinnervated vocal cord did not regain normal movement, both of the patients obtained excellent improvement in phonation.     

Functional differences between the two bellies of the cricothyroid muscle

The contraction of the cricothyroid (CT) muscle, which results in a decrease in the distance between the thyroid and cricoid cartilages, is considered to be the main factor in lengthening the vocal folds. This is achieved by rotation of the CT joint. The CT muscle is composed of two distinct bellies, the pars recta and the pars obliqua. The function of each subunit is not clearly understood, although it is believed that they act differently because their fibers run in different directions. To clarify the function of the two bellies in phonation, the fundamental frequency (F0), vocal intensity, subglottic pressure, vocal fold length, and CT distance were measured using an in vivo canine laryngeal model. On the basis of these measurements, we demonstrated that the two bellies are varied in their effect on raising the pitch, rotation, and forward translation of the CT joint. The stimulation of the pars recta nerve resulted in a greater increase in the F0 value compared with that of pars obliqua. The combined activity of the pars recta and pars obliqua is important in adjustment of the vocal fold length. The CT approximations directed parallel to the pars recta and pars obliqua simultaneously were more effective in elevation of the pitch than the approximation placed parallel to the pars recta only. This finding may be clinically significant with regard to CT approximation thyroplasty in human trails.     

Endolaryngeal contact pressures

In this work, we present a new method for in vivo endolaryngeal contact pressure measurement with a miniature pressure transducer. Using this methodology, contact pressures can be measured during videoendoscopy at different locations between the artyenoids and also at various locations along the membranous vocal folds. Twenty adults with organic and functional voice disorders and two vocally healthy adults participated as subjects. Endolaryngeal contact pressure measures were made during a series of phonatory tasks varying pitch, loudness, and phonatory onset and offset. Measures were also made during nonphonatory tasks, including throat clearing, coughing, Valsalva maneuvres, and gagging. The most remarkable findings were: (1) interarytenoid contact pressures were considerably greater than intraglottal contact pressures; (2) interarytenoid contact pressures were greater for lower than higher pitches; (3) both interarytenoid and intraglottal contact pressures were remarkably large during hard glottal attack; and (4) overall, the largest endolaryngeal pressures were recorded between the arytenoids, during a thoracic fixation maneuver and during gag reflex.     

Cell proliferation in the process of oviducal tissue remodeling during induced molting in hens

BACKGROUND: After surgical correction of their esophageal atresia and tracheoesophageal fistula (EA-TEF), many patients exhibit evidence of esophageal dysmotility. Controversy exists as to whether the esophageal motility disorders result from denervation caused by surgery or from an inherent abnormal innervation of the esophagus. METHODS: The present study used an Adriamycin-induced EA-TEF fetal rat model to trace the course and branching of both the vagus and recurrent laryngeal nerves. Abnormalities observed in EA-TEF rat fetuses include: (1) fewer branches from both recurrent laryngeal nerves; (2) deviation of the left vagus from its normal course below the aorta, passing behind the fistula to approach and join with the right vagus to form a single nerve trunk on the right side of the esophagus; (3) relatively few branches from the single vagal nerve trunk (composed of fibers of the left and the right vagus) on the surface of the lower esophagus. CONCLUSIONS: Fetuses affected by EA-TEF have inherent abnormalities in the course and branching pattern of the vagus nerves as they descend through the thorax, culminating in a deficient extrinsic nerve fiber plexus in the lower esophagus. These observations may account for the esophageal motility disorders seen in patients who have EA-TEF even before surgical intervention.     

Breathing at low lung volumes and chest strapping: a comparison of lung mechanics

In six normal subjects forced expiratory flow rates increased progressively with increasing degrees of chest strapping. In nine normal subjects forced expiratory flow rates increased with the time spent breathing with expiratory reserve volume 0.5 liters above residual volume, the increase being significant by 30 s (P less than 0.01), and flow rates were still increasing at 2 min, the longest time the subjects could breathe at this lung volume. The increase in flow after low lung volume breathing (LLVB) was similar to that produced by strapping. The effect of LLVB was diminished by the inhalation of the atropinelike drug ipratropium. Quasistatic recoil pressures were higher following strapping and LLVB than on partial or maximal expiration, but the rise in recoil pressure was insufficient to account for all the observed increased in maximum flow. We suggest that the effects of chest strapping are due to LLVB and that both cause bronchodilatation.