Preliminary Experience with 3-Dimensional Exoscope-Assisted Laryngoplasty.

OBJECTIVE: Laryngoplasty requires the manipulation of the vocal folds, which are not visible during the operation. The widespread use of this technique is limited by the need for adequate knowledge of anatomy, the small surgical field, and the high level of skill required for the procedure. An exoscope has been developed to provide a stereoscopic view similar to that of a microscope while using the same compact endoscopic tool. This study aimed to determine whether the three-dimensional (3D) exoscopic surgical technique could be applied to laryngoplasty and explore its possibility to ultimately replace the current approach. METHODS: This was a retrospective case series analysis, which included 28 patients with hoarseness who underwent surgery with (Exoscope; n = 12) or without (Macrosurgery; n = 16) a 3D exoscope between July 2018 and February 2021. The feasibility of performing all surgical steps with the 3D exoscope was evaluated. The Exoscope and Macrosurgery groups were compared for surgical time, vocal function outcomes, and complications. Questionnaires were completed by medical staff regarding the usefulness of medical education. RESULTS: No intraoperative or postoperative complications occurred in either procedure. The operative time was similar in both groups. The vocal function outcomes were also comparable between the groups. Questionnaires revealed that the exoscope was useful in terms of sharing information on surgical procedures and anatomy, as well as functioning as an educational tool. CONCLUSION: While this was a preliminary study, our results indicated that the exclusive use of the 3D exoscope was feasible for open approaches. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:1813-1819, 2024.

Effect of Aging on Vocal Outcomes After Laryngeal Reinnervation Combined With Arytenoid Adduction.

OBJECTIVE: To evaluate the impact of aging on vocal function following laryngeal reinnervation combined with arytenoid adduction (AA) in the treatment of paralytic dysphonia. METHODS: Sixty-eight patients with unilateral vocal fold paralysis who underwent refined nerve-muscle pedicle flap (NMP) implantation and AA were classified into four groups according to age: under 50 years (-50), in their 50s, 60s, and 70 years and older (70+). These groups consisted of 15, 14, 22, and 17 patients, respectively. Their vocal function was followed periodically for 24 months after surgery. RESULTS: Vocal function in all groups showed significant improvement after surgery. Significant improvements in vocal function were observed during a 24-month follow-up period: maximum phonation time in the -50 and 50 seconds groups; pitch range and voice handicap index-10 in the -50, 50s, and 60s groups; "Grade" in the -50, 50s, and 70+ groups; and "Breathiness" and voice-related quality of life in all groups. There were no significant differences in vocal function among the four groups, except for pitch range, at the 24-month postoperative assessment. CONCLUSIONS: Although the younger groups tended to exhibit better vocal function compared to the older groups 24 months postoperatively, the refined NMP+AA proved effective in the treatment of breathy dysphonia resulting from unilateral vocal fold paralysis, not only in the younger population but also in the older population.

Comparison of Botulinum Toxin Injections and Type 2 Thyroplasty for Adductor Spasmodic Dysphonia.

OBJECTIVES: Injection of botulinum toxin type A (BTX) into intrinsic laryngeal muscles is the current gold standard therapy for adductor spasmodic dysphonia (AdSD). However, a surgical procedure could potentially offer more stable and long-lasting voice quality to AdSD patients. Here, we report the long-term results of type 2 thyroplasty (TP2) with TITANBRIDGE® (Nobelpharma, Tokyo, Japan) compared with those of BTX injections. METHODS: In total, 73 AdSD patients visited our hospital between August 2018 and February 2022. Patients were provided the option of BTX injections or TP2. They were assessed via the Voice Handicap Index (VHI)-10 before treatments and at scheduled clinical follow-ups at 2, 4, 8, and 12 weeks for BTX and at 4, 12, 26, and 52 weeks for TP2. RESULTS: Overall, 52 patients selected the BTX injection and had a pre-injection mean VHI-10 score of 27.3 ± 8.8. Following injections, the scores significantly improved to 21.0 ± 11.1, 18.6 ± 11.5, and 19.4 ± 11.7 at 2, 4, and 8 weeks, respectively. There were no significant differences between the pre-injection scores and the 12-week scores (21.5 ± 10.7). Alternately, 32 patients opted to be treated with TP2 and had a pre-treatment mean VHI-10 score of 27.7. All patients reported an improvement in their symptoms. Additionally, the mean VHI-10 score significantly improved to 9.9 ± 7.4 at 52 weeks following treatment. There was a significant difference between the two treatment groups at 12 weeks. Some patients received both treatments. CONCLUSION: These preliminary results provide important insights into the value of TP2 as a potential permanent treatment for AdSD patients. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:3443-3448, 2023.

Human papillomavirus-related multiphenotypic sinonasal carcinoma: A report of two patients and review of the literature.

Human papillomavirus (HPV)-related multiphenotypic sinonasal carcinoma (HMSC) is a recently described sinonasal tract tumor that is associated with high-risk HPV subtype infection. Despite histological features that are suggestive of a high-grade malignant tumor, the prognosis of HMSC is relatively good; however, the clinical features of this tumor are poorly understood. Here, we describe two patients with HMSC. The first was initially diagnosed with adenoid cystic carcinoma of the right nasal cavity; the tumor was extirpated via endoscopic endonasal surgery. Seventy-four months later, the tumor recurred in the right inferior turbinate and was diagnosed as HMSC after biopsy, whereupon it was resected en block via endoscopic endonasal surgery. No adjuvant therapy was administered during either episode; moreover, no recurrences have occurred during the 44 months since the second operation. The second patient was diagnosed with HMSC based on the biopsy of the tumor occupying the left nasal cavity. The tumor was completely resected under endoscopic endonasal surgery, and no adjuvant therapy was administered. There has been no recurrence for 15 months after the operation. Herein, we also review the clinical features of this tumor type based on 69 previously reported cases as well as our patients.

Spasmodic dysphonia: An overview of clinical features and treatment options.

Spasmodic dysphonia (SD) is considered a rare focal laryngeal dystonia characterized by task-specific voice dysfluency resulting from selective intrinsic laryngeal musculature hyperfunction. Symptoms may be attenuated by a sensory trick. Although SD can be seen at times in generalized dystonia syndrome, it is typically a sporadic phenomenon, and the involvement of the laryngeal adductor muscles is more common than that of the abductor muscles. This research reviews the literature for the pathogenesis, clinical characteristics, treatment options, and current management methods of SD. Technological advances have enabled clinicians to better understand the connection between laryngeal function and dysfunction. Refinements in imaging and genetic investigation techniques have helped better understand the underlying mechanisms of this neurolaryngology disorder. Currently, the standard of care for SD is the symptomatic management of botulinum toxin (BT) chemodenervation. This is supported by a large body of literature attesting to its efficacy in many different research studies, particularly in the uncomplicated adductor form of the disorder. Efforts towards surgical treatment predate the development of BT treatment by a decade, but the long-term efficacy has not been proven and, further research is expected. Symptom relief in patients with abductor SD and dystonia with tremors after surgical and BT treatments and those in patients remains suboptimal.

Validity of intraoperative voice monitoring undergoing type 2 thyroplasty with titanium bridges for adductor spasmodic dysphonia.

Objectives: The success of type 2 thyroplasty (TP2) for adductor spasmodic dysphonia (AdSD) depends on the selection of optimally sized titanium bridges, which requires accurate assessment of intraoperative vocal changes. While this procedure has traditionally been performed according to the laryngologist's experience, the most appropriate method for voice monitoring and selection of titanium bridge size remains to be determined. This study aimed to investigate evaluation parameters useful for voice monitoring, as these may allow less experienced surgeons to perform TP2 properly. Methods: In this prospective study, voice monitoring was performed in 18 patients with AdSD patients undergoing TP2. Evaluations were performed preoperatively, intraoperatively, 13 weeks postoperatively, and 52 weeks postoperatively using GRBAS (grade, roughness, breathiness, asthenia, and strain), as well as perceptual judgment and acoustic analyses. Results: Preoperative and intraoperative assessments of the G, R, B, and S parameters, perceptual judgment, and harmonic-to-noise ratio (HNR) were in moderate or better agreement. Intraoperative and 13- or 52-week postoperative measurements of the R, B, and G parameters and strangulation, tremor, and HNR were also in high agreement. When two different sizes of titanium bridges were compared (unselected vs. selected), ratings for G, R, S, strangulation, tremor, jitter, shimmer, HNR, standard deviation of F0, and degree of voice breaks were better for the selected width than the unselected width. Conclusion: The candidate items for intraoperative voice monitoring during TP2 for AdSD are G, R, strangulation, tremor, and HNR. The use of these items may help to ensure successful TP2 and contribute to the advancement of laryngeal framework surgery. Level of evidence: Level 4.

[Anatomy for Endoscopic Endonasal Skull Base Surgery].

Endoscopic endonasal skull base surgery has become popular due to its minimally invasive nature to the patient and the development of various medical devices. The reason why it is considered less invasive is that it is possible to reach the anterior skull base lesion using the corridor of the nasal cavity and paranasal sinuses. The roles of the nasal sinuses include acting as breathing pathways, warming, humidifying, and filtering of inhaled air, olfaction, and being a resonant cavity, all of which are important for a comfortable life, and the loss of these functions reduces the quality of life. Therefore, to perform endoscopic endonasal skull base surgery in a minimally invasive and safe manner, it is necessary to understand the anatomy of the nasal sinuses to reach anterior skull base lesions while preserving nasal structures as much as possible. This article describes the normal local anatomy of the nasal cavity and the paranasal sinuses, as well as the surgical techniques, especially the anterior skull base approach and the pterygopalatine fossa approach, for endoscopic endonasal skull base surgery.

Effect of Voice Therapy as a Supplement After Reinnervation Surgery for Breathy Dysphonia Due to Unilateral Vocal Fold Paralysis.

OBJECTIVE: To evaluate whether vocal function exercises (VFE) could be an adjunct treatment for patients with unilateral vocal fold paralysis (UVFP) who were not satisfied with their postoperative voices after reinnervation surgeries. STUDY DESIGN: Retrospective. METHODS: Medical records of the patients with UVFP who underwent laryngeal reinnervation between October 2011 and October 2014 were reviewed. Patients were classified into two groups: one received VFE according to patients' desire (VFE group) and the other did not have voice therapy (control group). Effects of VFE were assessed by vocal fold vibration (regularity, amplitude and glottal gap), aerodynamic measurements (maximum phonation time (MPT) and mean airflow rate (MFR)), GRBAS scale, acoustic parameters (pitch range, pitch perturbation and amplitude perturbation quotients (PPQ, APQ), and noise-to-harmonics ratio (NHR)) and subjective evaluation by patients (Voice Handicap Index-10 (VHI-10)). Phonatory function was also compared between the two groups at three time points: before reinnervation surgery, before VFE, and after VFE. RESULTS: Thirty patients were enrolled (11 men, 19 women). The VFE group included eight patients, and 22 patients served as controls. In the VFE group, several parameters (amplitude, MPT, MFR, pitch range, APQ, and NHR) did not improve significantly after surgery, while all parameters examined improved significantly in the control group. After VFE, amplitude, glottal gap, MFR, B score, pitch range, and PPQ showed significant improvement, while the control group did not show a significant improvement except in VHI-10, during the corresponding period. Significant differences in G and B scores and VHI-10 between the two groups were observed at the third time point. CONCLUSIONS: VFE may be used as an adjunct treatment for patients with UVFP who are not satisfied with their voices after reinnervation surgery. However, phonatory function after VFE may not reach the same level as for those who are satisfied with their voices after reinnervation surgery.

Rabbit model with vocal fold hyperadduction.

OBJECTIVE: Adductor spasmodic dysphonia (AdSD) is caused by hyperadduction of the vocal folds during phonation, resulting in a strained voice. Animal models are not yet used to elucidate this intractable disease because AdSD has a difficult pathology without a definitive origin. For the first step, we established an animal model with vocal fold hyperadduction and evaluated its validity by assessing laryngeal function. METHODS: In this experimental animal study, three adult Japanese 20-week-old rabbits were used. The models were created using a combination of cricothyroid approximation, forced airflow, and electrical stimulation of the recurrent laryngeal nerves (RLNs). Cricothyroid approximation was added to produce a glottal slit. Thereafter, both RLNs were electrically stimulated to induce vocal fold hyperadduction. Finally, the left RLN was transected to relieve hyperadduction. The sound, endoscopic images, and subglottal pressure were recorded, and acoustic analysis was performed. RESULTS: Subglottal pressure increased significantly, and the strained sound was produced after the electrical stimulation of the RLNs. After transecting the left RLN, the subglottal pressure decreased significantly, and the strained sound decreased. Acoustic analysis revealed an elevation of the standard deviation of F0 (SDF0) and degree of voice breaks (DVB) through stimulation of the RLNs, and degradation of SDF0 and DVB through RLN transection. Formant bands in the sound spectrogram were interrupted by the stimulation and appeared again after the RLN section. CONCLUSION: This study developed a rabbit model with vocal fold hyperadduction . The subglottal pressure and acoustic analysis of this model resembled the characteristics of patients with AdSD. This model could be helpful to elucidate the pathology of the larynx caused by hyperadduction, and evaluate and compare the treatments for strained phonation.

Titanium bridge modification for type 2 thyroplasty to improve device mechanical & safety performance.

OBJECTIVE: Titanium bridges are used to separate the thyroid ala during type 2 thyroplasty for adductor spasmodic dysphonia. Revision surgeries have adventitiously indicated that bridge wing failure occurs in the area of the medial hole in some cases. This study investigated the rate and cause of device malfunctions and developed an improved device. METHODS: We conducted a questionnaire survey to determine the number of surgeries performed in Japan up to the end of 2014, and to obtain information about revision cases. In addition, damage analyses were performed on the fracture surfaces of recovered titanium bridges through use of scanning electron microscopy (SEM). RESULTS: Between 2002 and 2014, titanium bridges were used in 385 patients. Revision surgery was performed in 19 cases. Revision surgeries revealed that in 11 cases breakage occurred in the wings of the device in the region of the medial hole. However, such fractures were not associated with any signs of recurrence or any adverse events. SEM analyses of fracture surfaces confirmed that fatigue fractures were caused by repeated bending stress in the area of the medial hole. Based on these results, the shape of the hole was changed from round to oval and the wing thickness was increased to prevent breakage. CONCLUSIONS: The wings of titanium bridges may break without any associated signs, symptoms or tissue damage. Based on the malfunctions detected and analyses of the devices recovered following malfunction, changes to the specification were made for commercial development of the titanium bridge.

Effects and Differences of Voice Therapy on Spasmodic Dysphonia and Muscle tension dysphonia: A Retrospective Pilot Study.

OBJECTIVES: Laryngeal and voice findings of adductor spasmodic dysphonia (AdSD) and muscle tension dysphonia (MTD) are similar, and it is difficult to distinguish between both disorders. The purpose of this study is to ascertain the effect of voice therapy on MTD and AdSD and clarify their difference. METHODS: A total of 49 patients, including 22 patients with MTD (MTD group) and 27 patients with AdSD (SD group), were included in the study. The MTD scores were evaluated, and aerodynamic analysis (maximum phonation time [MPT], mean airflow rate [MFR], highest pitch, lowest pitch, and pitch range), perceptual evaluation (Strangulation, Interruption, and Tremor), acoustic analysis (PPQ, APQ, NHR, and DVB), and subjective assessment (voice handicap index-10 [VHI-10]) were performed before and after voice therapy. RESULTS: The MTD score, highest pitch, pitch range, strangulation, PPQ, APQ, NHR, and VHI-10 showed significant improvement after treatment in the MTD groups. On the other hand, the effect of voice treatment on AdSD was poor despite the improvement in the MTD score. CONCLUSIONS: This study could serve as a basis for conducting prospective studies to verify the effects of voice therapy on MTD and AdSD.

Botulinum toxin injection into the intrinsic laryngeal muscles to treat spasmodic dysphonia: A multicenter, placebo-controlled, randomized, double-blinded, parallel-group comparison/open-label clinical trial.

BACKGROUND AND PURPOSE: Botulinum toxin (BT) injection into the laryngeal muscles has been a standard treatment for spasmodic dysphonia (SD). However, few high-quality clinical studies have appeared, and BT is used off-label in most countries. METHODS: We performed a multicenter, placebo-controlled, randomized, double-blinded, parallel-group comparison/open-label clinical trial to obtain approval for BT (Botox) therapy in Japan. Twenty-four patients (22 with adductor SD and two with abductor SD) were enrolled. The primary end point was the change in the number of aberrant morae (phonemes) at 4 weeks after drug injection. The secondary end points included the change in the number of aberrant morae, GRBAS scale, Voice Handicap Index (VHI), and visual analog scale (VAS) over the entire study period. RESULTS: In the adductor SD group, the number of aberrant morae at 4 weeks after injection was reduced by 7.0 ± 2.30 (mean ± SE) in the BT group and 0.2 ± 0.46 in the placebo group (p = 0.0148). The improvement persisted for 12 weeks following BT injections. The strain element in GRBAS scale significantly reduced at 2 weeks after BT treatment. The VHI and VAS scores as subjective parameters also improved. In the abductor SD group, one patient responded to treatment. Adverse events included breathy hoarseness (77.3%) and aspiration when drinking (40.9%) but were mild and resolved in 4 weeks. CONCLUSIONS: Botulinum toxin injection was safe and efficacious for the treatment of SD. Based on these results, BT injection therapy was approved as an SD treatment in Japan.

The prevalence and clinical features of spasmodic dysphonia: A review of epidemiological surveys conducted in Japan.

OBJECTIVES: Spasmodic dysphonia (SD) is a rare disease and its epidemiological status is unclear. This review aimed to explore the current prevalence and clinical features of SD in Japan. METHODS: We reviewed Japanese surveys of SD and compared them to surveys reported from other countries. We focused on SD prevalence, clinical features (SD type, sex and age), and treatment modalities. RESULTS: The SD prevalence in Japan was 3.5-7.0/100,000, similar to that in Rochester (NY, USA) and Iceland. Adductor SD predominated (90-95%) and females were four-fold more likely to be affected than males. Mean age at onset was approximately 30 years in Japan. Several years elapsed from onset to diagnosis. The most frequent treatment was botulinum toxin injection, and surgical intervention, particularly type 2 thyroplasty is becoming more popular. CONCLUSIONS: Our review demonstrated some differences of clinical features of SD in Japan compared with other countries, such as a greater female predominance and younger age of onset. Many physicians and patients may be unfamiliar with the clinical features of SD leading to delayed of diagnosis. Therefore, we proposed diagnostic criteria to facilitate early diagnosis and an appropriate choice of treatment modalities.

Hyperactive sensorimotor cortex during voice perception in spasmodic dysphonia.

Spasmodic dysphonia (SD) is characterized by an involuntary laryngeal muscle spasm during vocalization. Previous studies measured brain activation during voice production and suggested that SD arises from abnormal sensorimotor integration involving the sensorimotor cortex. However, it remains unclear whether this abnormal sensorimotor activation merely reflects neural activation produced by abnormal vocalization. To identify the specific neural correlates of SD, we used a sound discrimination task without overt vocalization to compare neural activation between 11 patients with SD and healthy participants. Participants underwent functional MRI during a two-alternative judgment task for auditory stimuli, which could be modal or falsetto voice. Since vocalization in falsetto is intact in SD, we predicted that neural activation during speech perception would differ between the two groups only for modal voice and not for falsetto voice. Group-by-stimulus interaction was observed in the left sensorimotor cortex and thalamus, suggesting that voice perception activates different neural systems between the two groups. Moreover, the sensorimotor signals positively correlated with disease severity of SD, and classified the two groups with 73% accuracy in linear discriminant analysis. Thus, the sensorimotor cortex and thalamus play a central role in SD pathophysiology and sensorimotor signals can be a new biomarker for SD diagnosis.

Endoscopic endonasal management of esthesioneuroblastoma: A retrospective multicenter study.

OBJECTIVE: The aim of the present study was to illustrate the safety and utility of the endoscopic endonasal approach (EEA) for the treatment of esthesioneuroblastomas (ENB). METHODS: We retrospectively reviewed patients with a diagnosis of ENB between March 2008 and February 2016 at 10 tertiary referral hospitals in Japan, and assessed demographic data, stage of disease, surgical approach, outcomes and postoperative complications. RESULTS: A total of 22 patients (10 males and 12 females; mean age at presentation, 49.0 years) underwent endoscopic endonasal resection of newly diagnosed ENBs. Dulguerov staging at presentation was T1, 6 patients; T2, 9 patients; T3, 5 patients; and T4, 2 patients. As surgical procedures, unilateral resection via EEA was performed in 12 patients aiming preservation of the contralateral olfactory system, and bilateral resection via EEA was done in 10 patients. Post-operative radiotherapy was done in 20 patients. Pathological margin studies revealed margin-free resections in 21 patients (95.5%). The mean period of follow-up was 44 months. Local recurrence was observed in one T2 patient 12 months after bilateral resection. All patients were alive at the last follow-up, and 21 patients showed no evidence of disease. No post-operative complications including bleeding, CSF leak and meningitis were identified. Preservation of olfactory function was achieved in 11 patients (91.7%). CONCLUSION: The results of the present study indicate the safety and utility of multilayer resection using EEA for treatment of ENBs.

Long-term Evaluation of Type 2 Thyroplasty with Titanium Bridges for Adductor Spasmodic Dysphonia.

Objectives Standard treatments of adductor spasmodic dysphonia (AdSD) provide temporary relief of symptoms. Type 2 thyroplasty offers a long-term solution; however, long-term voice outcome data are lacking. The objective of this study was to assess the long-term voice outcomes of type 2 thyroplasty with titanium bridges through use of a validated voice questionnaire. Study Design Case series with chart review. Setting University hospital. Subjects and Methods Forty-seven consecutively enrolled patients with AdSD underwent type 2 thyroplasty with titanium bridges between August 2006 and November 2014. Questionnaires were completed during regularly scheduled follow-ups and, in some cases, were sent to patients who missed follow-up appointments. In 2015, questionnaires were mailed to all 47 patients and included a Voice Handicap Index-10 evaluation, as well as questions on postoperative vocal symptoms, surgical site, and status of the implanted titanium bridges. Results Of 47 patients with AdSD, 31 (66%) completed the questionnaires. The average follow-up interval was 41.3 months. No patient reported experiencing an adverse event around the surgical site, and almost all were satisfied with their voices postoperatively. The mean postoperative (>3 years) Voice Handicap Index-10 score improved significantly, from 26.3 to 9.4 (n = 17, P = .0009). Conclusions Type 2 thyroplasty for AdSD significantly improved patient quality of life and voice symptoms and continued to do so long after the surgery. The results of this study suggest that type 2 thyroplasty provides relief from vocal symptoms in patients with AdSD for >3 years.

Arytenoid adduction combined with nerve-muscle pedicle flap implantation or type I thyroplasty.

OBJECTIVES/HYPOTHESIS: To evaluate vocal function after refined nerve-muscle pedicle (NMP) flap implantation with arytenoid adduction (AA) compared with type I thyroplasty with AA for patients with unilateral vocal fold paralysis (UVFP) and to evaluate the degree of patient satisfaction following the refined NMP with AA. STUDY DESIGN: A retrospective review of clinical records of 52 patients with UVFP who received AA + NMP (NMP group, n = 40) or AA + type I thyroplasty (type I group, n = 12) as a single-stage operation between April 1999 and December 2011. METHODS: Evaluation of vocal fold vibration, aerodynamic analysis, perceptual evaluation, acoustic analysis, and subjective assessment were performed preoperatively and at two different postoperative periods (short term: within 3 months and long term: >12 months). RESULTS: All parameters except for glottal gap of the vocal fold vibration, maximum phonation time (MPT), and mean airflow rate revealed significant improvement between the short- and long-term assessments in the NMP group. On the contrary, the type I group did not show significant change of any parameters during postoperative periods. In the NMP group, the measurements for regularity of the vocal fold vibration and MPT at the long-term assessment were significantly favorable compared with the type I group. In the NMP group, subjective assessment (Voice Handicap Index-10 and Voice-Related Quality of Life) revealed significant improvement between the short- and long-term assessments. CONCLUSIONS: In comparison with the type I group, significant improvement of vocal function patient satisfaction during the long-term follow-up period after AA combined with the refined NMP was confirmed. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:159-166, 2017.

Voice tuning with new instruments for type II thyroplasty in the treatment of adductor spasmodic dysphonia.

OBJECTIVE: Adductor spasmodic dysphonia is a rare voice disorder characterized by strained and strangled voice quality with intermittent phonatory breaks and adductory vocal fold spasms. Type II thyroplasty differs from previous treatments in that this surgery does not involve any surgical intervention into the laryngeal muscle, nerve or vocal folds. Type II thyroplasty intervenes in the thyroid cartilage, which is unrelated to the lesion. This procedure, conducted with the aim of achieving lateralization of the vocal folds, requires utmost surgical caution due to the extreme delicacy of the surgical site, critically sensitive adjustment, and difficult procedures to maintain the incised cartilages at a correct position. During surgery, the correct separation of the incised cartilage edges with voice monitoring is the most important factor determining surgical success and patient satisfaction. METHODS: We designed new surgical instruments: a thyroid cartilage elevator for undermining the thyroid cartilage, and spacer devices to gauge width while performing voice monitoring. These devices were designed to prevent surgical complications, and to aid in selecting the optimal size of titanium bridges while temporally maintaining a separation during voice monitoring. RESULTS: We designed new surgical instruments, including a thyroid cartilage elevator and spacer devices. Precise surgical procedures and performing voice tuning during surgery with the optimal separation width of the thyroid cartilage are key points for surgical success. CONCLUSION: We introduce the technique of voice tuning using these surgical tools in order to achieve a better outcome with minimal surgical complications.

Modulation of satellite cells activity and MyoD in rat thyroarytenoid muscle after reinnervation.

OBJECTIVES/HYPOTHESIS: To examine modulation of M-cadherin, a marker for satellite cells (SCs); and MyoD, which may indicate the myogenic activity following recurrent laryngeal nerve (RLN) denervation and immediate reinnervation; and to elucidate the correlation between their modulations and establishment of neuromuscular junctions (NMJs) in the reinnervated rat thyroarytenoid (TA) muscle. STUDY DESIGN: Quantitative real-time polymerase chain reaction qPCR and histologic assessment of the TA muscle following RLN transection and anastomosis. METHODS: Rats were divided into three groups: 1) denervation alone (DNV) (n = 60), 2) denervation with anastomosis (ANS) (n = 60), and 3) sham-operated controls (n = 12). Animals were sacrificed at 3 days and 1, 3, and 5 weeks after treatment. TA muscles harvested from 40 animals from each DNV and ANS group; all of sham group were subjected to qPCR for assessment of the modulation of M-cadherin and MyoD; and the remaining larynges of DNV and ANS group were used for histologic analysis. RESULTS: The expression levels of messenger RNAs (mRNAs) encoding M-cadherin and MyoD in the TA muscle of the DNV group were significantly higher (P < 0.05) than in the control throughout the study period. These mRNA levels in the ANS group were significantly higher (P < 0.05) at ≤ 1 week than in the controls but fell to control levels at ≥ 3 weeks. In the ANS group, recovery of muscle area and NMJs structure occurred by 3 weeks. CONCLUSION: These data suggested that NMJ formation following reinnervation might prompt recovery of M-cadherin and MyoD mRNA expression to the quiescent level of SCs.