Ultrasound-guided injection into the lateral crico-arytenoid muscle: a pilot study.

OBJECTIVES: The anterior, percutaneous Botulinum neurotoxin (BoNT) injection in the lateral cricoarytenoid muscle (LCA) guided by laryngeal electromyography (LEMG) is considered the golden standard treatment for several neurolaryngological disorders. The study presented in this article aims to assess the effectiveness of an alternative approach by which the injection is performed laterally under ultrasound monitoring. STUDY DESIGN: Anatomical dissection study in human cadavers. SETTINGS: Academic health care center. METHODS: Ultrasound-guided bilateral dye (0.1 mL of dye solution containing cold-curing polymers, latex, acrylates, acrylic esters, alcohol, and green color) injection in the LCA was performed by means of 24G needles and 1 mL syringes using the lateral approach. The dye location and distribution were assessed by anatomic dissection, performed immediately after the injection. RESULTS: In 9/10 specimens, the dye was exclusively detectable in the LCA. In 1/10 case (left side), the dye could not be delivered in the LCA because of unintended penetration of the thyroid cartilage by the needle during injection. Anatomic dissection confirmed that the dye spread neither into the thyroarytenoid (TA) nor the cricothyroid muscle (CT). CONCLUSIONS: The anatomic dissection following lateral dye injection in the LCA under ultrasound guide confirmed the precision of this approach in delivery a substance exclusively in a pre-determined target. This feature makes this method an interesting addition or alternative to the standard LEMG-guided BoNT injection at least when the LCA is its target. LEVEL OF EVIDENCE: III.

High-resolution magnetic resonance and mass spectrometry imaging of the human larynx.

High-resolution, noninvasive and nondestructive imaging of the subepithelial structures of the larynx would enhance microanatomic tissue assessment and clinical decision making; similarly, in situ molecular profiling of laryngeal tissue would enhance biomarker discovery and pathology readout. Towards these goals, we assessed the capabilities of high-resolution magnetic resonance imaging (MRI) and matrix-assisted laser desorption/ionisation-mass spectrometry (MALDI-MS) imaging of rarely reported paediatric and adult cadaveric larynges that contained pathologies. The donors were a 13-month-old male, a 10-year-old female with an infraglottic mucus retention cyst and a 74-year-old female with advanced polypoid degeneration and a mucus retention cyst. MR and molecular imaging data were corroborated using whole-organ histology. Our MR protocols imaged the larynges at 45-117 µm2 in-plane resolution and capably resolved microanatomic structures that have not been previously reported radiographically-such as the vocal fold superficial lamina propria, vocal ligament and macula flavae; age-related tissue features-such as intramuscular fat deposition and cartilage ossification; and the lesions. Diffusion tensor imaging characterised differences in water diffusivity, primary tissue fibre orientation, and fractional anisotropy between the intrinsic laryngeal muscles, mucosae and lesions. MALDI-MS imaging revealed peptide signatures and putative protein assignments for the polypoid degeneration lesion and the N-glycan constituents of one mucus retention cyst. These imaging approaches have immediate application in experimental research and, with ongoing technology development, potential for future clinical application.

Crumley's Classification of Laryngeal Synkinesis: A Comparison of Laryngoscopy and Electromyography.

OBJECTIVES/HYPOTHESIS: Applying the principles of misdirected nerve regeneration to the larynx, Roger Crumley in 1989 coined the term laryngeal synkinesis (LS) which he later (2000) classified into 4 types (type I - good voice, type II - involuntary twitches and poor voice, type III - adduction during inspiration, type IV - abduction during phonation). Neurophysiological data were not available for all LS patients at that time. The current study was undertaken to utilize and test the Crumley classification for a clinical interrater comparison and, secondly, compare predicted with actual laryngeal electromyography (LEMG) results. STUDY DESIGN: Descriptive study. METHODS: Laryngoscopic and LEMG data of patients with unilateral vocal fold paralysis (VFP) of 6 months duration or longer were combined for retrospective evaluation. Forty-five data sets were available for laryngoscopic classification by two local laryngologists and by Roger Crumley. Twenty-three data sets with complete thyroarytenoid (TA) and posterior cricoarytenoid (PCA) - EMG data were used to compare predicted with actual LEMG results. RESULTS: Local laryngologists were able to classify 24 of 45, Crumley 30 of 45 cases into one of the 4 synkinesis types. There was substantial agreement between examiners (Cohens Kappa 0.66 [P < .001]). Comparison of predicted and actual LEMG data showed only moderate agreement. EMG sykinesis rates were lower in TA than in PCA and highest in Crumley type I cases. CONCLUSION: The Crumley classification is helpful in describing and understanding synkinesis. It does not always correlate predictably with actual LEMG data. A complete LEMG mapping of all intrinsic muscles may improve understanding of chronic VFP. LEVEL OF EVIDENCE: 4. Laryngoscope, 131:E1605-E1610, 2021.

Prognostic value of the posterior cricoarytenoid muscle atrophy in computerized tomography scans for unilateral vocal fold paralysis recovery.

OBJECTIVES: To evaluate the prognostic value of the posterior cricoarytenoid (PCA) muscle atrophy observed on neck computed tomography (CT) in patients with unilateral vocal fold paralysis. METHODS: CT images of 87 subjects with unilateral vocal fold paralysis (UVFP) were evaluated to analyze the PCA muscle atrophy and to measure the severity of the PCA muscle atrophy in semi-quantitative manner. The grading of the PCA muscle atrophy was compared with the recruitment pattern of laryngeal electromyography (LEMG) and restoration of vocal fold movement. RESULTS: The PCA muscle was identifiable on CT in 73 subjects. Using the PCA muscle atrophy as an indicator of UVFP, we correctly predicted the paralysis in 69 (94.5%). Grade of the PCA muscle atrophy is significantly correlated with recruitment pattern of LEMG. If the positive result is defined as the PCA muscle showed moderate to severe degree of atrophy, we could predict the persistent UVFP in 88% of patients. CONCLUSIONS: PCA muscle atrophy identified on CT scan in patients with UVFP, is associated with low rates of return of mobility in the affected vocal fold.

Ultrasonography-guided electromagnetic needle tracking in laryngeal electromyography.

PURPOSE: The clinical evaluation of vocal fold movement disorders should contain the electromyography of the laryngeal muscles (LEMG). The most challenging point in LEMG is the right positioning of the EMG needle in the small target muscles. As the results of the EMG have great influence in the decision of treatment it is important to confirm the results of this examination. Anatomical structures of the larynx should be identified with laryngeal ultrasonography and the ultrasonography (US)-guided electromagnetic needle tracking should guide the LEMG needle to the target muscle. METHODS: The thyroarytenoid (TA) and cricothyroid (CT) muscles had been evaluated in 19 patients (20 examinations). The US-guided transcutaneous LEMG using electromagnetic needle tracking was performed by one ENT doctor and all examinations had been video monitored. The videos were analyzed for the accuracy rate and the visibility of the important laryngeal structures. RESULTS: The laryngeal structures were identified in all the cases using laryngeal ultrasonography. The examination times of the US-guided LEMG were acceptable (8 min, 32 s). The US-guided LEMG was feasible in 56 (36 TA, 20 CT) examinations. The TA and CT could be visualized successfully but in 17 examinations (30%) the signal was not stable. We could still reach the target muscles in more than 50% of these cases. CONCLUSION: US-guided electromagnetic needle tracking in LEMG helps to determine the exact position of the laryngeal structures. With further technical improvement of the stability of the electromagnetic needle tracking signal the US-guided electromagnetic needle tracking of the target muscles in the larynx could help to improve the accuracy of the transcutaneous LEMG.

Identifying the ideal tracheostomy site based on patient characteristics during percutaneous dilatational tracheostomy without bronchoscopy.

BACKGROUND: We previously reported that percutaneous dilatational tracheostomy (PDT) can be safely performed 2 cm below the cricothyroid membrane without the aid of a bronchoscope. Although our simplified method is convenient and does not require sophisticated equipment, the precise location for tracheostomy cannot be confirmed. Because it is recommended that tracheostomy be performed at the second tracheal ring, we assessed whether patient characteristics could predict the distance between the cricothyroid membrane and the second tracheal ring. METHODS: Data from 490 patients who underwent three-dimensional neck computed tomography from January 2012 to December 2015 were analyzed, and the linear distance from the upper part of the cricoid cartilage (CC) to the lower part of the second tracheal ring (2TR) was measured in the sagittal plane. RESULTS: The mean CC-to-2TR distance was 25.26 mm (95% CI 25.02-25.48 mm). Linear regression analysis showed that the predicted CC-to-2TR distance could be calculated as -5.73 + 0.2 × height (cm) + 1.22 × sex (male: 1, female: 0) + 0.01 × age (yr) -0.03 × weight (kg) (adj. R2 = 0.55). CONCLUSIONS: These results suggest that height and sex should be considered when performing PDT without bronchoscope guidance.

Radiographic muscle invasion not a recurrence predictor in HPV-associated oropharyngeal squamous cell carcinoma.

OBJECTIVE: To determine whether muscle invasion evident on pretreatment imaging in p16 + oropharyngeal squamous cell carcinoma (OPSCC) correlates with recurrence. STUDY DESIGN: Retrospective review. METHODS: Two-hundred and seventy-six patients with p16 + OPSCC treated at a tertiary referral center from 2003 to 2015 were analyzed. All scans were reviewed by a dedicated neuroradiologist with subspecialty expertise in head and neck imaging. Radiographic evidence of muscle invasion to the genioglossus, hyoglossus, medial pterygoid, and prevertebral muscles was analyzed. Local and regional recurrence rates were compared between the muscle invasion and no muscle invasion groups. RESULTS: One hundred and ninety patients met inclusion criteria with adequate follow-up data and pretreatment imaging. Patients were predominantly male (87.5% male) and smokers (65.6% smokers) with a mean age of 56.7 (standard deviation: 9.0 years). Most commonly invaded muscles in the muscle invasion group were hyoglossus (57.8%) and genioglossus (56.3%). There was no statistically significant difference in primary site or nodal recurrence between the combined group, including definite or possible muscle invasion and the group without muscle invasion (P = 0.205 and P = 0.569, respectively). Additionally, no statistically significant difference was present in recurrence-free and disease-specific survival between the two groups at 3- and 5-year follow-up (P > 0.05). CONCLUSION: Radiographic evidence of muscle invasion does not appear to be a predictor of human papilloma virus (+) OPSCC recurrence. Additional studies are needed to validate our findings. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:871-876, 2019.

Implications of Synkinesis in Unilateral Vocal Fold Paralysis.

Objectives In patients with unilateral vocal fold paralysis (UVFP), laryngeal electromyography (LEMG) occasionally observes synkinesis in laryngeal muscles, a condition that could impair vocal fold mobility and voice control. This study aims to evaluate the impact of synkinesis on UVFP patients. Study Design A retrospective case-control study. Setting Medical center. Subjects and Methods Patients with UVFP onset >6 months were recruited (N = 104). The outcome measurements included LEMG, quantitative LEMG analysis of thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex, glottal gap measured by videolaryngostroboscopy, voice-related quality of life, and voice acoustic analysis. Results According to the LEMG analysis, 8 patients (8%) had synkinesis, and 96 (92%) did not. In the synkinesis group, TA-LCA turn frequency in the lesioned side was comparable to that in the healthy side ( P = .52). Patients in the synkinesis group had higher TA-LCA turn frequency ( P = .001), higher probability of cricothyroid muscle dysfunction ( P = .04), and better voice-related quality of life ( P = .01) but objective voice outcomes comparable to those in the nonsynkinesis group. Conclusions Patients with synkinesis will have near-complete restoration in TA-LCA turn frequency but still experience voice impairment, a finding that is compatible with the mechanism of aberrant reinnervation. However, patients with synkinesis have better disease-related quality of life than do those without synkinesis.

Disease Characteristics and Electromyographic Findings of Nonsurgery-Related Unilateral Vocal Fold Paralysis.

OBJECTIVE: The detailed characteristics and prognosis of nonsurgery-related unilateral vocal fold paralysis (NSUVFP) are currently unclear. This study evaluated the extent of laryngeal nerve lesions and the individual characteristics for patients with NSUVFP. STUDY DESIGN: Retrospective, case series. METHODS: Patients with unilateral vocal fold paralysis (UVFP) were evaluated using videolaryngostroboscopy and quantitative laryngeal electromyography. The side of nerve lesions, involvement of the external branch of the superior laryngeal nerve (eSLN), and complete vocal fold motion recovery were evaluated after ≥ 6 month follow-up. RESULTS: A total of 207 UVFP patients were recruited, including 153 surgery-related UVFP and 54 NSUVFP patients. Thirty-four (63%) and 20 (37%) NSUVFP patients were further assigned to idiopathic and nonsurgery-related-nonidiopathic (NSNI) groups, respectively. In the idiopathic group, eSLN lesions occurred in all six (100%) patients with right-side paralysis, but in only six of 28 (21%) patients with left-side paralysis (P < 0.001). The turn frequency of the paralyzed thyroarytenoid-lateral cricoarytenoid muscle complex is lower in the NSNI group (333.1 ± 192.1) compared with the idiopathic group (490.2 ± 255.1) (P = 0.02). The probability of complete vocal fold motion recovery did not differ among groups (P > 0.05). CONCLUSION: Idiopathic and NSNI UVFP have different clinical presentations defined by laryngeal electromyography. NSNI UVFP had more severe denervation changes compared with idiopathic UVFP. These results may support two pathogenic mechanisms for idiopathic UVFP: 1) neuropathy specifically involving left recurrent laryngeal nerve (RLN), and 2) neuropathy affecting nerves proximal to the RLN. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:1381-1387, 2017.

Thyroarytenoid muscle uptake and attenuation in PET/CT in elderly.

The objective of this study is to compare uptake and attenuation on positron emission tomography/computed tomography (PET/CT) imaging modality at the thyroarytenoid muscle between subjects aged less and older than 65 years old. The study design is retrospective chart review. The setting is academic medical center. PET/CT images of 60 patients aged less than 65 years old and 60 patients aged more than 65 years old were selected. Demographic data were collected. Both the groups were compared with respect to the maximum standardized uptake value (SUV max) and CT attenuation of bilateral thyroarytenoid muscles. The mean SUV max of the right thyroarytenoid muscle was 2.09 ± 0.8 in the group of patients aged less than 65 years old compared to 1.9 ± 0.6 in the group of patients aged more than 65 years old. For the left thyroarytenoid muscle, the mean SUV max in the first and second groups was, respectively, 2 ± 0.6 and 1.9 ± 0.6. The differences were not statistically significant. As for the CT attenuation, the mean value at the right thyroarytenoid muscle in the first and second groups was, respectively, 31.2 ± 0.8 HU and 20.8 ± 14.4 HU (p < 0.05). At the left thyroarytenoid muscle, the mean value was, respectively, 29.6 ± 9.9 and 22.8 ± 15 (p < 0.05). This study suggests that CT attenuation measurements can be used for objectively assessing the change in the density of aging thyroarytenoid muscle.

Diagnosis and management of unilateral thyroarytenoid muscle palsy.

The objective of this study is to assess and propose a method of diagnosis and management of patients with unilateral thyroarytenoid muscle palsy (TAMP). This is a retrospective review of clinical records. The records of seven patients diagnosed as having idiopathic TAMP were reviewed. Despite the adductive and abductive functions of the vocal folds being within normal range, apparent palsy was seen in the unilateral thyroarytenoid muscle of these patients. TAMP was confirmed by laryngeal electromyography, and the adductive and abductive movements of the vocal folds were evaluated as the mobility of the arytenoid cartilages by three-dimensional computed tomography and endoscopy. Most of patients with TAMP had been diagnosed as having other diseases or normal, and in one patient, it took over 6 years to establish a correct diagnosis. Two patients recovered by conservative treatment; however, in five patients, TAMP remained even after 6 months. In 4 of those 5 patients, treatment with hyaluronic acid injections was performed. In the remaining patient, surgical treatment, namely, nerve-muscle pedicle flap implantation was performed, which resulted in a favorable recovery of phonation. The average maximum phonation time (MPT) of all patients was extended from 11.4 (±4.4) s before treatment to 19.9 (±4.3) s after treatment, and the pitch range was also increased from 25.1 (±7.2) to 34.6 (±5.8) semitones following our management course. Our results indicate that there is a possibility that TAMP can be diagnosed and treated sufficiently. Therefore, further research toward establishing the concept of and treatment for TAMP is anticipated.

Features of Vocal Fold Adductor Paralysis and the Management of Posterior Muscle in Thyroplasty.

OBJECTIVE: To present the pathologic characteristics of unilateral recurrent nerve adductor branch paralysis (AdBP), and to investigate the management of posterior cricoarytenoid (PCA) muscle on the basis of our experience of surgical treatment for AdBP. STUDY DESIGN: This is a retrospective review of clinical records METHODS: Four cases of AdBP, in which surgical treatment was performed, are presented. AdBP shows disorders of vocal fold adduction because of paralysis of the thyroarytenoid and lateral cricoarytenoid muscles. The PCA muscle, dominated by the recurrent nerve PCA muscle branch, does not show paralysis. Thus, this type of partial recurrent nerve paresis retains the abductive function and is difficult to distinguish from arytenoid cartilage dislocation because of their similar endoscopic findings. The features include acute onset, and all cases were idiopathic etiology. Thyroarytenoid muscle paralysis was determined by electromyography and stroboscopic findings. The adduction and abduction of paralytic arytenoids were evaluated from 3 dimensional computed tomography (3DCT). RESULTS: In all cases, surgical treatments were arytenoid adduction combined with thyroplasty. When we adducted the arytenoid cartilage during inspiration, strong resistance was observed. In the two cases where we could cut the PCA muscle sufficiently, the maximum phonation time was improved to ≥30 seconds after surgery, from 2 to 3 seconds preoperatively, providing good postoperative voices. In contrast, in the two cases of insufficient resection, the surgical outcomes were poorer. CONCLUSIONS: Because the preoperative voice in AdBP patients is typically very coarse, surgical treatment is needed, as well as ordinary recurrent nerve paralysis. In our experience, adequate PCA muscle resection might be helpful in surgical treatment of AdBP.

Cricothyroid joint anatomy as a predicting factor for success of cricoid-thyroid approximation in transwomen.

OBJECTIVES/HYPOTHESIS: Cricoid-thyroid approximation (CTA) performed to elevate the vocal pitch in transwomen fails in about one-third of the patients. The purpose of this study was to test the feasibility of predicting the likelihood of success of CTA by preoperative determination of the crico-thyroid joint (CTJ) type using three-dimensional (3-D) images derived from high-resolution computer tomography (HRCT). STUDY DESIGN: Prospective cohort study of 18 transwomen who underwent CTA at our institution. METHODS: All patients had a preoperative and a postoperative HRCT of the larynx, as well as pre- and postoperative measurements of the fundamental vocal pitch (F0 ). RESULTS: Three-dimensional images showed type A CTJs in 11 patients and type B or C CTJs in seven patients (see below for the definition of these types). Cricoid-thyroid approximation raised the F0 on average by 76 Hz in patients with type A CTJs and by 45 Hz in patients with type B/C CTJs. Moreover, CTA produced a vocal fold elongation of 17% in larynges with type A joint but only of 3% in larynges with type B/C joints. CONCLUSION: Three-dimensional images allow the differentiation of type A versus type B/C CTJs but not the distinction between type B and type C CTJs. Both vocal pitch elevation and vocal fold elongation following CTA are significantly greater in patients with type A CTJs than in patients with type B/C CTJs. Based on these preliminary results, we recommend identifying the CTJ type on 3-D images and limiting CTA to patients with type A CTJs. LEVEL OF EVIDENCE: 4. Laryngoscope, 126:1380-1384, 2016.

Localization of the cricothyroid muscle under ultrasound guidance for vagal nerve mapping.

During surgical removal of tumors of the skull base or cerebellopontine angle with brainstem compression, the vagus nerve is at a high risk for injury that can result in permanent or transient swallowing and speech dysfunction. Intramuscular recording of cricothyroid muscle can be used for vagal nerve mapping during intraoperative neurophysiologic monitoring so as to prevent the above complications. However, it is a small muscle that lies beneath the strap muscles over the anterior neck and is not easily accessible by a blind approach. Here, we present a case in which cricothyroid muscle was identified for precise electrode placement under ultrasound guidance during preparation for intraoperative monitoring. We concluded that localization of the cricothyroid muscle by ultrasonography proved to be a feasible and easy technique, and the compound muscle action potential recorded by this approach is clearly recognizable during intraoperative vagal nerve mapping.

[Role of ultrasound in airway management].

Recent advancement in ultrasound technology allows us to visualize detailed structures around the airway. One of the important roles of the airway ultrasound is to identify cricothyroid membrane where the emergent invasive access should be performed. Now we can assess the risk of difficult cricothyroidotomy before anesthesia of which the new ASA difficult airway guideline suggests. Airway ultrasound can also be used to confirm correct position of the tracheal tube and laryngeal mask, difficult laryngoscopy prediction in obese patients, assessing vocal cord function, prediction of the post extubation stridor, and so on. We also introduce perioperative evaluation of the airway via sonography (PEAS) protocol in this review.

Toward fully automated multicriterial plan generation: a prospective clinical study.

PURPOSE: To prospectively compare plans generated with iCycle, an in-house-developed algorithm for fully automated multicriterial intensity modulated radiation therapy (IMRT) beam profile and beam orientation optimization, with plans manually generated by dosimetrists using the clinical treatment planning system. METHODS AND MATERIALS: For 20 randomly selected head-and-neck cancer patients with various tumor locations (of whom 13 received sequential boost treatments), we offered the treating physician the choice between an automatically generated iCycle plan and a manually optimized plan using standard clinical procedures. Although iCycle used a fixed "wish list" with hard constraints and prioritized objectives, the dosimetrists manually selected the beam configuration and fine tuned the constraints and objectives for each IMRT plan. Dosimetrists were not informed in advance whether a competing iCycle plan was made. The 2 plans were simultaneously presented to the physician, who then selected the plan to be used for treatment. For the patient group, differences in planning target volume coverage and sparing of critical tissues were quantified. RESULTS: In 32 of 33 plan comparisons, the physician selected the iCycle plan for treatment. This highly consistent preference for the automatically generated plans was mainly caused by the improved sparing for the large majority of critical structures. With iCycle, the normal tissue complication probabilities for the parotid and submandibular glands were reduced by 2.4% ± 4.9% (maximum, 18.5%, P=.001) and 6.5% ± 8.3% (maximum, 27%, P=.005), respectively. The reduction in the mean oral cavity dose was 2.8 ± 2.8 Gy (maximum, 8.1 Gy, P=.005). For the swallowing muscles, the esophagus and larynx, the mean dose reduction was 3.3 ± 1.1 Gy (maximum, 9.2 Gy, P<.001). For 15 of the 20 patients, target coverage was also improved. CONCLUSIONS: In 97% of cases, automatically generated plans were selected for treatment because of the superior quality. Apart from the improved plan quality, automatic plan generation is economically attractive because of the reduced workload.