Laryngeal neurophysiology and its clinical uses

Quantitative Analysis of Unilateral and Bilateral Vocal Fold Immobility

OBJECTIVE

To analyze the correlation between clinical and video laryngoscopy findings for 89 patients with bilateral vocal fold immobility (BVFI), unilateral vocal fold immobility (UVFI), and healthy controls by quantitative analysis of normalized laryngeal outlet (NLO), bowing index (BI), and supraglottic compression (SGC).

METHODS

Laryngoscope pictures were taken by two reviewers, and all pictures were standardized by scaling and calibrating to the same width and height in Image J. Three reviewers used quantitative measures to calculate BI, NLO, and SGC in Image J. We assessed reliability for each measurement by two-factor analysis of variance (ANOVA) without replication to calculate the interclass correlation coefficient. Analysis was broken down for each measurement in each group of interest by using a one-way test. The total glottic area was obtained by calculating the normalized glottal gap area from each image of maximum glottal closure during phonation.

RESULTS

Overall reliability of all the measurements was 0.69 (IQ 0.58-0.83). Mean NLO from UVFI, BVFI, and control groups differed significantly. There was no significant difference between control and BVFI. The total glottic area did not consistently predict normalized laryngeal outlet values. Mean normalized laryngeal outlet values of UVFI and BVFI were significantly smaller in the BVFI groups compared with controls and UVFI. BI values consistently predicted total glottic area in the BVFI group. Static SGC measurement did not predict a difference between groups.

CONCLUSION

This is a reliable novel technique, which can be utilized in clinical settings. These measurements have clinical relevance for managing voice disorders. NLO is the most accurate measurement correlating with glottal incompetence. BI findings are sufficiently specific to identify between UVFI and BVFI.

Prediction of Disease Free Survival in Laryngeal and Hypopharyngeal Cancers Using CT Perfusion and Radiomic Features: A Pilot Study

(1) Purpose: The objective was to evaluate CT perfusion and radiomic features for prediction of one year disease free survival in laryngeal and hypopharyngeal cancer. (2) Method and Materials: This retrospective study included pre and post therapy CT neck studies in 36 patients with laryngeal/hypopharyngeal cancer. Tumor contouring was performed semi-autonomously by the computer and manually by two radiologists. Twenty-six radiomic features including morphological and gray-level features were extracted by an internally developed and validated computer-aided image analysis system. The five perfusion features analyzed included permeability surface area product (PS), blood flow (flow), blood volume (BV), mean transit time (MTT), and time-to-maximum (Tmax). One year persistent/recurrent disease data were obtained following the final treatment of definitive chemoradiation or after total laryngectomy. We performed a two-loop leave-one-out feature selection and linear discriminant analysis classifier with generation of receiver operating characteristic (ROC) curves and confidence intervals (CI). (3) Results: 10 patients (28%) had recurrence/persistent disease at 1 year. For prediction, the change in blood flow demonstrated a training AUC of 0.68 (CI 0.47-0.85) and testing AUC of 0.66 (CI 0.47-0.85). The best features selected were a combination of perfusion and radiomic features including blood flow and computer-estimated percent volume changes-training AUC of 0.68 (CI 0.5-0.85) and testing AUC of 0.69 (CI 0.5-0.85). The laryngoscopic percent change in volume was a poor predictor with a testing AUC of 0.4 (CI 0.16-0.57). (4) Conclusions: A combination of CT perfusion and radiomic features are potential predictors of one-year disease free survival in laryngeal and hypopharyngeal cancer patients.

Videolaryngostroboscopy following Frontolateral Laryngectomy with Sternohyoid Flap

We conducted a retrospective study to analyze the videostroboscopic findings in a group of 21 patients who underwent vertical frontolateral laryngectomy with reconstruction by use of the sternohyoid muscle flap. They had T1b and T2 glottic tumors and a follow-up of more than 1 year. Three observers analyzed the recorded videostroboscopic data. The cases in which the stroboscopic evaluation of the vocal folds was incomplete were studied in regard to the clinical staging, the supraglottic hyperfunction, and the vibratory site; the Fisher exact test was applied. The glottic closure was complete in 15 individuals, and 6 had irregular vocal gaps. The site of vibration was glottic in 10 cases, supraglottic in 7, and mixed in 4. The amplitude was normal on 4 and slightly diminished on 9 preserved sides, whereas it was moderately or severely diminished on 16 and absent on 5 reconstructed sides. The mucosal wave vibratory pattern was always totally present on 15 preserved and 5 reconstructed sides: normal or slightly diminished in the preserved vocal folds, and moderately or severely diminished in the reconstructed ones. The reconstructed vocal folds had a nonvibrating portion in 5 cases. The movement extent of the preserved side was larger than that of the other side in 8 cases, and the sides were similar in 13 cases. The symmetry was regular in 18 cases. The periodicity was always or generally regular in 9 cases. There was supraglottic hyperadduction in 16 cases, with a lateral constriction predominance. The mucosal appearance was normal in 15 patients and wet in 6 patients. The epiglottis was straight in 14 cases and crescent in 7. Mucus formation was observed in 1 patient in the posterior vibratory portion. Videolaryngostroboscopy allowed thorough evaluation of the vibratory pattern of the vocal folds in 52.4% of the patients. The supraglottic hyperadduction component and the supraglottic vocal source presented difficulty for this evaluation. The site of vibration was glottic in 47.6%, supraglottic in 33.3%, and mixed in 19.1% of the cases. The vibratory pattern was diminished on both sides, but mainly on the reconstructed one.

Postoperative dysphagia versus neurogenic dysphagia: scintigraphic assessment

In order to differentiate the features of dysphagia that occur after supraglottic horizontal laryngectomy from those that occur during neurologic diseases, we divided 38 subjects into 3 groups and submitted them to oropharyngoesophageal scintigraphy. Group 1 (control group) included 15 healthy volunteeers; group 2 comprised 8 patients who had residual dysphagia at least 1 year after supraglottic laryngectomy; and group 3 included 15 patients with various neurologic and neuromuscular disorders. In group 1, the mean values (+/- 2 SD) of selected semiquantitative parameters were consistent with those reported in the literature for normal subjects. In group 2, oral, pharyngeal, and esophageal transit times were not significantly altered, and moderate tracheobronchial post-deglutitive aspiration was present (maximum value, 6.7%; mean value, 2.04%). The pharyngeal retention index was significantly increased (p = .0003) as compared to normal subjects in all cases (maximum value, 40%; mean value, 23%) and was associated in all cases with slight but consistent post-deglutitive aspiration. In group 3, the oral and esophageal phases were significantly prolonged and the retention indices were significantly increased. Statistical analysis documented a significant increase in oral transit time (p = .003), esophageal transit time (p = .01), oral retention index (p = .006), pharyngeal retention index (p = .0007), and esophageal retention index (p = .009) as compared to normal subjects. The swallowing pattern was also altered by 1) an early loss of the bolus from the oral cavity; 2) bolus fragmentation due to double or triple deglutition, reduced lingual propulsion, or the return of a small part of the bolus into the oral cavity during deglutition; and/or 3) double pharyngeal peaks in the activity-time curves. Tracheobronchial aspiration (maximum value, 90%; mean value, 9.70%) was present in some cases, mainly in patients affected by post-stroke dysphagia. On the basis of the obtained results and considering the low doses of radiation delivered to the patient (0.043 Gy), the limited invasiveness, and the excellent patient tolerance, scintigraphy appears to be clinically valid in the functional study of swallowing and in identifying different deglutition disorders.

Larynx preservation with supracricoid partial laryngectomy with cricohyoidoepiglottopexy. Correlation of videostroboscopic findings and voice parameters

Classically, the formation of a mucosal wave is dependent on the pliable mucosa present in the vocal fold. The supracricoid partial laryngectomy with cricohyoidoepiglottopexy is an organ preservation surgical technique in which both true vocal folds, both false vocal folds, both paraglottic spaces, and the entire thyroid cartilage are resected. The functional goal is speech and swallowing without a permanent tracheostomy. In an effort to further study voice production in these patients, we performed laryngeal stroboscopy in 5 patients. Analysis was performed with a modified Bless grading system. In addition, speech and voice parameters were also measured and correlated with stroboscopic findings. The key finding in this study was the presence of a periodic mucosal wave on the anterior aspect of the arytenoid cartilage, where it abuts the epiglottic cartilage. Patients with lower periodicity and symmetry scores tended to have lower jitter and shimmer percentages.

Aspiration in unilateral recurrent laryngeal nerve paralysis after surgery

PURPOSE

Dysphonia with hoarseness and breathiness are the key symptoms of unilateral recurrent laryngeal nerve (RLN) paralysis, whereas aspiration is not usually described. The aim of this prospective study was to assess the incidence of aspiration in patients with unilateral recurrent laryngeal nerve paralysis after head and neck or thoracic surgery.

PATIENTS AND METHODS

Five patients were included and evaluated within the first week and again 2 months postoperatively. Position, tone, and tension of the true vocal cord as well as assessment of the glottic axis, arytenoid position, laryngeal sensation, status of the pyriform sinus, and salivary stasis were studied. Swallowing evaluation was performed using flexible fiberoptic laryngoscopy during dry swallowing, thick cream, methylene blue liquid as well as with swallowing videofluoroscopy.

RESULTS

Three patients had no aspiration, one patient had silent aspiration, and one had symptomatic aspiration.

CONCLUSION

We conclude that aspiration may occur in unilateral recurrent laryngeal nerve paralysis and have to be systematically evaluated after pneumonectomy.