Combination thyroplasty and the "twisted larynx:" combined type IV and type I thyroplasty for superior laryngeal nerve weakness.

Vocal cord medialization through Isshiki type I thyroplasty is part of the standard approach for patients with unilateral vocal cord immobility secondary to recurrent laryngeal nerve paralysis. However, several other modalities have been used to treat the symptomatic "twisted" larynx caused by unilateral superior laryngeal nerve weakness. The Isshiki type IV thyroplasty (cricothyroid approximation) specifically addresses cricothyroid muscle weakness, but, canine studies at the Mayo Clinic demonstrated a trend toward decreased acoustic power and sound intensity with simulated cricothyroid activity. Thus it is reasoned that addition of an ipsilateral type I thyroplasty should help compensate for this power loss. Using videostroboscopic and acoustic analysis, 9 patients with unilateral superor laryngeal nerve weakness were treated with combination type IV and type I thyroplasty. Subjective dysphonia and objective visual and acoustic measurements revealed postoperative improvement in most patients. The combination type IV and type I thyroplasty is recommended for surgical treatment of patients with superior laryngeal nerve weakness, because it addresses cricothyroid muscle weakness without compromising vocal power.     

A comparison of type I thyroplasty and arytenoid adduction

Glottal incompetence is a common laryngeal disorder causing impaired swallowing and phonation. The resultant voice has been characterized as weak and breathy with a restricted pitch range. Currently, medialization thyroplasty and arytenoid adduction are two of the surgical treatments for patients with glottal incompetence. However, few studies have evaluated the changes in objective measures of speech with type I thyroplasty and arytenoid adduction. In this study, 59 patients with glottal incompetence underwent either type I thyroplasty or arytenoid adduction. Acoustic (jitter, shimmer, and harmonics-to-noise ratio) and aerodynamic (airflow, subglottic pressure, and glottal resistance) measures were obtained both pre- and postoperatively. No significant differences were found among acoustic or aerodynamic measures for operation type. However, a significant pre/postsurgery effect was observed for translaryngeal airflow. In addition, no significant differences were found among the measures for patients with traditional compared with nontraditional operative indications. Patients who developed glottal insufficiency due to previous laryngeal surgery (e.g., vocal fold stripping) demonstrated no statistically significant improvement in acoustic or aerodynamic measures following thyroplasty or arytenoid adduction.     

Vocal Fold Paralysis Following Radiotherapy for Nasopharyngeal Carcinoma: Laryngeal Electromyography Findings

Laryngeal electromyography was used to study the pattern of neurological injury in three patients with unilateral vocal fold paralysis following radiotherapy for nasopharyngeal carcinoma. The thyroarytenoid and cricothyroid muscles were assessed to give an indication of recurrent and superior laryngeal nerve function. Two patients demonstrated both recurrent and superior laryngeal neuropathy suggesting injury at the skull base. The other patient had only recurrent laryngeal neuropathy indicating more distal involvement. Subclinical neuropathic changes were seen in two cases on the side contralateral to the vocal fold paralysis. These patients may be at increased risk of developing bilateral vocal fold paralysis and potentially life-threatening airway obstruction. Long-term follow-up is recommended for such patients, especially if medialization thyroplasty is being considered. This is the first report describing the use of electromyography to determine the pattern of nerve injury in patients with vocal fold paralysis following head and neck radiotherapy.     

Voice-Related Quality of Life (V-RQOL) following type I thyroplasty for unilateral vocal fold paralysis

Unilateral vocal fold paralysis is a common clinical problem which frequently causes severe dysphonia. Various treatment options exist for this condition, with the type I thyroplasty being one of the more commonly performed surgical procedures for vocal rehabilitation. The Voice-Related Quality of Life (V-RQOL) Measure is a validated outcomes instrument for voice disorders. This study measured the V-RQOL of patients with unilateral vocal fold paralysis who had undergone a type I thyroplasty and compared these scores to those of patients with untreated and uncompensated unilateral vocal fold paralysis and to normals. Treated patients had significantly higher domain and overall V-RQOL scores than untreated patients, but also scored lower than normals. These differences were true across gender and age. Patients who were more distant from surgery had lower V-RQOL scores than those who had more recently been treated. It is concluded that type I thyroplasty leads to a significantly higher V-RQOL for patients with unilateral vocal fold paralysis. This study also demonstrates further the utility of patient-oriented measures of treatment outcome.     

Early results of transcutaneous injection laryngoplasty with micronized acellular dermis versus type-I thyroplasty for glottic incompetence dysphonia due to unilateral vocal fold paralysis

Medialization thyroplasty (type I) has become the gold standard to improve glottic closure due to unilateral vocal fold paralysis. A newer injection method utilizing homologous collagen from cadaveric human tissue has been described as an attractive alternative as no donor site is required, there is a very low risk of hypersensitivity, and the intact, acellular collagen fibers may suffer a reduced long-term reabsorption rate. Preliminary results on eight patients comparing presurgical and postsurgical parameters (perceptual, stroboscopic, acoustic, and aerodynamic) revealed comparable results when compared with a control group of individuals, age- and sex-matched, that had undergone standard medialization thyroplasty (type I). Further study is needed to assess the long-term results with this minimally invasive method of vocal fold medialization.     

The type I thyroplasty window: Implications of normal thyroid cartilage thickness

This paper describes the dimensions and placement of a standardizedIsshiki Type I thyroplasty window and the thickness of the thyroid cartilage at the window corners. In addition, the intraoperative optimal medialization of a series of windows is compared to these cartilage thickness measurements and these comparisons analyzed for their implications in surgical approach.Fifty-one Type I thyroplasty windows were fashioned on 42 larynges (cadavericand surgical). Measurements were taken of the window sizes, depth of medialization (surgical cases), and thickness of the thyroid cartilage at the four corners of the rectangular window. Sexes were kept separate because of inherent size differences of male and female larynges. From these physical measurements it is found that: (1) the thyroid cartilage window is not uniform in thickness throughout; there is a gradation of thickness from anterior to posterior and from superior to inferior; (2) when comparing the average depth of medialization to the window cartilage thickness in a standardized Isshiki window, the average distance of window depression almost equals the thyroid cartilage thickness, whereas posteriorly there is slightly more distance between the external surface of the window cartilage and the internal surface of the surrounding thyroid cartilage. Implications of the varying thickness of the thyroid cartilage and its relationship to the average depth of medialization in a standardized Isshiki thyroplasty window are discussed.     

The role of strap muscles in phonation—In vivo caninelaryngeal model

In spite of the presumed importance of the strap muscles on laryngealvalving and speech production, there is little research concerning the physiological role and the functional differences among the strap muscles. Generally, the strap muscles have been shown to cause a decrease in the fundamental frequency (F₀) of phonation during contraction. In this study, an in vivo canine laryngeal model was used to show the effects of strap muscles on the laryngeal function by measuring the F₀, subglottic pressure, vocal intensity, vocal fold length, cricothyroid distance, and vertical laryngeal movement. Results demonstrated that the contraction of sternohyoid and sternothyroid muscles corresponded to a rise in subglottic pressure, shortened cricothyroid distance, lengthened vocal fold, and raised F₀ and vocal intensity. The thyrohyoid muscle corresponded to lowered subglottic pressure, widened cricothyroid distance, shortened vocal fold, and lowered F₀ and vocal intensity. We postulate that the mechanism of altering F₀ and other variables after stimulation of the strap muscles is due to the effects of laryngotracheal pulling, upward or downward, and laryngotracheal forward bending, by the external forces during strap muscle contraction.     

Analysis of Voice and Quantitative Measurement of Glottal Gap After Thyroplasty Type I in the Treatment of Unilateral Vocal Paralysis

Thyroplasty type I is one of several surgical treatments in which improving the voice of unilateral vocal fold paralysis is the ultimate objective. The goal of the surgery is the medialization of the paralyzed vocal fold. The purpose of this study is to evaluate the effectiveness of thyroplasty type I through acoustical analysis, aerodynamic measures, and quantitative videostroboscopic measurements. We report on 20 patients with unilateral vocal cord paralysis who underwent thyroplasty type I. We performed preoperative and postoperative video image analysis (normalized glottal gap area) and computer-assisted voice analysis (fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, mean phonation time, mean flow rate, mean subglottic pressure) in all patients. The glottal gap was significantly reduced after thyroplasty type I. Postoperative voice quality was characterized by an improved pitch and amplitude pertubation (jitter and shimmer), phonation time (mean phonation time), and subglottic pressure (mean subglottic pressure). Thyroplasty type I is an effective method for regaining glottal closure and vocal function.     

Type I thyroplasty: Pitfalls of modifying the Isshiki approach.How I do it

The Isshiki type I thyroplasty medializes the membranous portion of thevocal fold. Since its introduction into this country more than 10 years ago, several authors have reported modifications of the Isshiki approach primarily for the purpose of speeding the operation and “simplifying” the procedure. The major modifications have included: (a) incision, versus retraction, of the strap muscles; (b) removing the window external perichondrium; (c) varying the placement and size of the window and prosthesis; (d) removal of the window cartilage; (e) fiberoptic versus nonvisualization of the larynx intraoperatively; (f) incision of the inner perichondrium; and (d) use of silastic block substitutes. The principles of Isshiki's original technique will be reiterated in the ongoing discussion, and the reasons for not modifying certain aspects of the technique will be examined from the standpoint of complications and negative impact that manifest when modification is done.     

“Compensatory falsetto”: Effects on vocal quality

The term “compensatory falsetto”, for the purpose of this investigation, refers to the development of an abnormally high-pitched voice in the presence of laryngeal pathology where more socially acceptable lower pitched voice production is possible. The purpose of this investigation was to compare laryngeal compensations and their effects on objective measures of vocal function during production of compensatory falsetto voice. Eighteen patients with abnormally high-pitched voice in the presence of underlying laryngeal pathology were evaluated in the Department of Otolaryngology at the University of Miami School of Medicine from January 1988 through December 1992 and were diagnosed with “compensatory falsetto”. Vocal fold paralysis (n = 11) was the most common laryngeal pathology. Vibratory characteristics were evaluated through videostrobolaryngoscopic examination. Acoustic and aerodynamic parameters assessed included fundamental frequency, jitter rate, harmonic-to-noise ratio, glottal air flow, and maximum phonation time. Production of a higher-pitched voice appeared to improve glottic closure and decrease the amount of air loss during phonation. A corresponding increase in maximum phonation time and improvement in acoustic characteristics of jitter and harmonic-to-noise ratio was also observed.     

Comparison between thyroplasty type I andArytenoid rotation: a study of vocal fold vibration using excised human larynges

The purpose of this paper was to compare the vibration of the vocal fold submitted to Isshiki thyroplasty type I (TPI) to that of the contralateral one adducted by the arytenoid rotation (AR) technique. The vocal folds of ten human fresh excised larynges were medialized by TPI on one side and by rotation of the arytenoid on the contralateral side. Laryngeal vibration was artificially produced and was recorded by videostroboscopy. The images were subjectively and objectively analyzed. Subjective analysis included periodicity of vibratory cycles, features of the mucosal wave present on the TPI side, amplitude of vibration, and profile of free border of each vocal fold during the opening phase. Objective analyses were carried out on frame-by-frame digitalized images to determine amplitudes of vibrations and phase differences between the folds in three glottic regions (anterior, middle, and posterior). Subjective analysis revealed regular periodicity in 100% of the larynges, a decrease in the mucosal wave on the TPI side in 70%, reduction in amplitude in 30%, and a sigmoid profile of the free border on the TPI side in 80%. Objective analysis showed mean amplitude in the posterior glottic region on the TPI side significantly larger than that on the arytenoids rotation side and phase asymmetry in 90% of the larynges.     

Unilateral cricothyroid contraction and glottic configuration

It is frequently stated that unilateral cricothyroid muscle (CT) paralysis can be diagnosed by physical examination, noting rotation of the glottis, and shortening and vertical displacement of the ipsilateral vocal fold. These signs, however, are inconsistently observed, and there is considerable controversy regarding the direction of glottic rotation. To determine the effects of CT contraction on three-dimensional glottic configuration, we performed computerized tomography on cadaver larynges before and after simulated CT contraction. Radiopaque makers were used to compute distances. Unilateral CT contraction equally increased the length of both membranous vocal folds, and rotated the posterior glottis less than 1 mm. CT contraction neither adducted the vocal processes, nor significantly their altered vertical level. These results suggest that unilateral CT paralysis cannot be diagnosed on the basis of any clinically apparent change in glottal configuration.     

Relationship among glottal area, static supraglottic compression, and laryngeal function studies in unilateral vocal fold paresis and paralysis

In this study, we evaluated the relationship between laryngeal function measures and glottal gap ratio and normalized measures of supraglottic behaviors in patients with unilateral vocal fold paresis (UVFP). Thirty-one patients were found to have unilateral vocal fold paresis by videoendoscopy and laryngeal electromyography, and 13 controls participated in this study. Patients with UVFP demonstrated significantly larger glottal gap ratios (p = 0.016) than control subjects. The nonparalyzed or contralateral vocal fold was associated with significantly more static false vocal fold compression (p = 0.03) compared with the paralyzed vocal fold or with the controls. Patients with unilateral vocal fold paresis were divided into subgroups: those with normal or abnormal maximum phonation time, flow, or pressure measures. Smaller glottal gap ratios were identified in patients with normal maximum phonation times and flow measures. Greater false vocal fold activity was identified in unilateral vocal fold paresis patients with normal laryngeal function measures than in unilateral vocal fold paresis patients with abnormal measures. These findings suggest that some patients with documented unilateral paresis and glottal incompetence can compensate for vocal fold weakness such that their acoustic and aerodynamic measures are normal.     

Preliminary evaluation of selected acoustic and glottographic measures for clinical phonatory function analysis

Acoustic and glottographic measures may provide important information that could enhance clinical management and documentation of vocal dysfunction. Acoustic measures such as jitter and shimmer reflect “short-term” perturbations, or instabilities of the voice, and the coefficients of variation for frequency and for amplitude reflect “long-term” perturbations. Interpretations of these acoustic measures are based on the assumption that vocal perturbations may be related to laryngeal tissue abnormalities, asymmetries in vocal fold movement, or neuromuscular fluctuations in the respiratory, laryngeal, or vocal tract systems. The abduction quotient is a glottographic measure related to laryngeal adduction and is obtained from an analysis of the electroglottograph signal. The adduction measure appears to be independent of the acoustic perturbation measures. Interpretations of the acoustic and adductory measures may, therefore, complement each other for greater understanding of a patient's laryngeal behavior. Visual displays of the acoustic and glottographic signals also are discussed to demonstrate their value in voice signal interpretations. Case studies illustrate potential interpretations of the acoustic perturbation and abduction quotient measures.     

The dynamics of length change in canine vocal folds

The time courses of vocal fold elongation and contraction have beenmeasured as a function of intrinsic laryngeal muscle activity. The superior and recurrent laryngeal nerves of anesthetized canines were stimulated supramaximally (on-off in all combinations) while the vocal folds were surgically exposed and illuminated for conventional and higher speed (300 frames per second) video recording. Microsutures were placed on various points on the vocal folds to measure elongation and contraction. Vocal fold strain, defined as elongation divided by rest length, ranged from −17% to +45%. The typical time constant for exponential increase or decrease in strain was about 30 ms. This reflects primarily the intrinsic muscle activation times rather than a passive (inertial or viscoelastic) response of cricothyroid joint rotation or translation.     

Cooperative Regulation of Vocal Fold Morphology and Stress by the Cricothyroid and Thyroarytenoid Muscles

Voice is produced by vibrations of vocal folds that consist of multiple layers. The portion of the vocal fold tissue that vibrates varies depending primarily on laryngeal muscle activity. The effective depth of tissue vibration should significantly influence the vibrational behavior of the tissue and resulting voice quality. However, thus far, the effect of the activation of individual muscles on the effective depth is not well understood. In this study, a three-dimensional finite element analysis is performed to investigate the effect of the activation of two major laryngeal muscles, the cricothyroid (CT) and thyroarytenoid (TA) muscles, on vocal fold morphology and stress distribution in the tissue. Because structures that bear less stress can easily be deformed and involved in vibration, information on the morphology and stress distribution may provide a useful estimate of the effective depth. The results of the analyses indicate that the two muscles perform distinct roles, which allow cooperative control of the morphology and stress. When the CT muscle is activated, the tip region of the vocal folds becomes thinner and curves upward, resulting in the elevation of the stress magnitude all over the tissue to a certain degree that depends on the stiffness of each layer. On the other hand, the TA muscle acts to suppress the morphological change and controls the stress magnitude in a position-dependent manner. Thus, the present analyses demonstrate quantitative relationships between the two muscles in their cooperative regulation of vocal fold morphology and stress.     

Voice and Laryngeal Configuration of Men With Unilateral Vocal Fold Paralysis Before and After Medialization

Aim

To describe the laryngeal configuration and the voice of male patients diagnosed with unilateral vocal fold paralysis (UVFP) before and after medialization.

Methods

A retrospective study involving the collection of data from medical records of 142 patients diagnosed with UVFP from January 2003 to April 2009, submitted to auditory-perceptual assessment of voices and visual perception of laryngeal images before and after medialization.

Results

The study included data from 24 male patients, with an average of 60.7 years, who underwent three surgical medialization techniques (injection of hyaluronic acid, type I thyroplasty, and injection of Teflon). Before treatment, the position of the paralyzed vocal fold was seen to have a significant influence to the passing of the healthy vocal fold beyond the midline and on the overall degree of dysphonia. After treatment, the complete glottic closure; the free margin of the linear vocal fold; paralyzed vocal fold in the median position, reduction of hoarseness, roughness and breathiness (more frequently mild), and asthenia (more frequently normal and mild); tension and instability (more frequency normal); and a decrease in the overall degree of dysphonia were found to be significant.

Conclusion

The position of the paralyzed vocal fold influences the position of the healthy vocal fold in relation to the midline and the overall degree of dysphonia. All three treatments improved the glottic configuration and the voice of patients with UVFP.     

Thyroplasty as primary and adjunctive treatment of glottic insufficiency

This study addresses the role of medialization thyroplasty in a variety of vocal fold pathological conditions manifested by glottic insufficiency. In this series, most patients had preceding or concurrent phonosurgical procedures. Success of surgery was determined by subjective, audioperceptual judgments, acoustic analysis, and vocal function measures. Vocal fold pathology played a greater role in determining success than did the presence or absence of adjunctive surgical procedures. Thyroplasty Type I was effective in treating glottic insufficiency in patients previously treated with various augmentation procedures as well as in those undergoing simultaneous reinnervation and arytenoid adduction. Technical factors predisposing to complications included violation of inner thyroid cartilage perichondrium, small shim size, sacrifice of cartilagenous window, and mucosal penetration. Thyroplasty should be considered as a primary or adjunctive treatment of patients with glottic insufficiency, especially when preservation of membranous vocal fold structure is of primary importance.     

Comparing the Long-Term Outcome of Immediate Postoperative Facial Nerve Dysfunction and Vocal Fold Immobility After Parotid and Thyroid Surgery

SUMMARY: Hypothesis: The long-term recovery rate of immediate postoperative facial nerve dysfunction with an electrophysiologically and anatomically intact facial nerve is higher than the long-term recovery rate of immediate postoperative vocal fold immobility with an electrophysiologically and anatomically intact recurrent laryngeal nerve. Methods: A retrospective review of parotid and thyroid surgery with electrophysiologic monitoring of the facial and recurrent laryngeal nerves, respectively. Results: Forty-five consecutive patients had electrophysiologic and anatomic integrity of the facial nerve at the conclusion of the parotidectomy. Eight of 45 (18%) patients developed a postoperative facial nerve dysfunction. All eight patients with facial nerve dysfunction had complete return of facial nerve function within 3 months. A total of 102 consecutive patients underwent dissection of the recurrent laryngeal nerve during thyroid surgery. Seven of 102 (7%) had immediate unilateral vocal fold dysfunction. All 102 had electrophysiologic and anatomic integrity of the recurrent laryngeal nerve at the conclusion of the procedure. Two of 102 (2%) have clinically complete permanent vocal fold dysfunction. Five of seven (71%) with immediate complete vocal fold immobility had complete return of mobility. Conclusions: A higher immediate postoperative rate of transient facial nerve dysfunction is reported compared with vocal fold immobility in parotid and thyroid surgery, respectively (P < 0.05). Immediate postoperative facial nerve dysfunction with an electrophysiologically response at 1 mA and an anatomically intact facial nerve during parotid surgery resulted in a complete return of function in all cases in this series. Immediate postoperative vocal fold immobility with an electrophysiological response at 1 mA and an anatomically intact recurrent laryngeal nerve had a 30% rate of being permanent in this series.