Hong-Shik Choi

Feasibility of Robot-Assisted Neck Dissections via a Transaxillary and Retroauricular (“TARA”) Approach in Head and Neck Cancer: Preliminary Results

BackgroundRecently, robot-assisted neck dissection in thyroid cancer patients with lateral neck node metastasis has been demonstrated to be feasible. We realized the necessity of technical modification in order to apply robotic system to comprehensive neck dissection for head and neck squamous cell carcinoma. This study examined the feasibility and safety of transaxillary and retroauricular (“TARA”) approach for robotic neck dissection in patients with head and neck squamous cell cancer.MethodsFour human cadaveric dissections were followed by robotic neck dissections in seven patients with oral cavity or laryngopharyngeal cancer through TARA incision.ResultsIn all cases, vital structures including major vessels and nerves were preserved. The numbers of retrieved lymph nodes in robotic neck dissections were comparable with those in conventional neck dissections.ConclusionsRobotic neck dissection via TARA approach is a feasible and useful method with excellent cosmetic results for treating nodal metastasis in selected cases of head and neck squamous cell cancer.

Schwannoma in Head and Neck: Preoperative Imaging Study and Intracapsular Enucleation for Functional Nerve Preservation

Purpose In treating schwannoma patients, it is critical to determine the origin of the tumor to preserve nerve function. We evaluated the validity of preoperative imaging studies in distinguishing the neurological origin of the schwannomas of the head and neck, and the efficacy of intracapsular enucleation in preserving nerve function. Materials and Methods In 7 cases of schwannomas in the head and neck region, we predicted whether the tumor originated from the vagus nerve or the cervical sympathetic chain through imaging studies including computed tomography (CT) and magnetic resonance imaging (MRI). All patients were performed intracapsular enucleation, and the function of the vagus nerve and the sympathetic nerve was evaluated preoperatively and postoperatively. Results Preoperative imaging studies showed 6 cases where the tumor was located between the carotid artery and the internal jugular vein, and 1 case where the tumor was located posteriorly, displacing the carotid artery and the internal jugular vein anteriorly. At the time of operation, we confirmed schwannoma originating from the vagus nerve on the first 6 cases, and schwannoma originating from the sympathetic nervous system on the last case. All patients went through successful intracapsular enucleation, and of the seven schwannoma cases, 6 patients maintained normal postoperative neurological function (85.7%). Conclusion Preoperative imaging studies offer valuable information regarding the location and origination of the tumor, and intracapsular enucleation helped us to preserve the nerve function.

Voice analysis of patients with diverse types of Reinke's edema and clinical use of electroglottographic measurements

Conclusions. Reinkes edema shows a variety of clinical patterns and differences in voice analysis depending on its type. Electroglottographic measurements help to objectively assess the severity of edema and voice quality before and after surgery. Objectives. Reinkes edema manifests various clinical findings and different voice characteristics depending on the degree of swelling and the severity of voice impairment. The aim of this study was to compare the aerodynamic, acoustic and electroglottographic parameters for the different types of Reinkes edema according to its morphological, perceptual and histopathological classifications, and to assess voice quality in patients with Reinkes edema before and after laryngomicrosurgery. We also aimed to determine which parameter was most associated with the improvement in postoperative voice quality and to investigate the clinical usefulness of electroglottographic analysis in Reinkes edema. Material and methods. The clinical and voice records of 61 patients with Reinkes edema were reviewed. All the patients were classified according to stroboscopic findings (Yonekawas classification), perceptual grade and histopathological findings. Voice analysis of the perceptual, acoustic, aerodynamic and electroglottographic measurements was carried out using various classifications, and the voices of 23 patients who underwent laryngomicrosurgery were evaluated 2 months after surgery. Furthermore, the voices of 30 normal speakers (controls) were recorded and analyzed. Results. The fundamental frequency (FxM) of Yonekawa Type III was significantly lower than those of the other types of Reinkes edema, and the SD of the FxM, the percentage irregularity of the FxM (CFx) and the percentage irregularity of the amplitude were larger than those of the other types of Reinkes edema. The closed quotient was significantly higher in Yonekawa Type III. In addition, the mean flow rate (MFR), maximum phonation time and harmonics:noise ratio (HNR) differed significantly among the different types of Reinkes edema. The postoperative results showed an increase in the FxM and an improvement in the MFR, subglottic pressure, shimmer and HNR. Correlation analysis showed that jitter, the HNR, the mean closed quotient and the irregularity of the frequency were the parameters that had the best correlation with improvement in postoperative voice quality.

Function of the posterior cricoarytenoid muscle in phonation: in vivo laryngeal model.

The function of the posterior cricoarytenoid (PCA) muscle in phonation has not been well documented. To date, several electromyographic studies have suggested that the PCA muscle is not simply an abductor of the vocal folds, but also functions in phonation. This study used an in vivo canine laryngeal model to study the function of the PCA muscle. Subglottic pressure and electroglottographic, photogiottographic, and acoustic waveforms were gathered from five adult mongrel dogs under varying conditions of nerve stimulation. Subglottic pressure, fundamental frequency, sound intensity, and vocal efficiency decreased with increasing stimulation of the posterior branch of the recurrent laryngeal nerve. These results suggest that the PCA muscle not only acts to brace the larynx against the anterior pull of the adductor and cricothyroid muscles, but also functions inhibitorily in phonation by controlling the phonatory glottal width.

Evaluation of Performance of Several Established Pitch Detection Algorithms in Pathological Voices

Robust pitch estimation is important in many areas of speech processing. In voice pathology, diverse statistics extracted form pitch estimation were commonly used to test voice quality. In this study, we compared several established pitch detection algorithms (PDAs) for verification of adequacy of the PDAs. In the database of total pathological voices of 99 and normal voices of 30, an analysis of errors related with pitch detection was evaluated between pathological and normal voices, or among the types of pathological voices. Pitch errors of all PDAs used in this study more or less showed some changes between pathological and normal voices. According to the results of pitch errors, gross pitch error showed some increases in cases of pathological voices; especially excessive increase in PDA based on nonlinear time-series. In an analysis of types of pathological voices classified by aperiodicity and the degree of chaos, the more voice has aperiodic and chaotic, the more growth of pitch errors increased. Consequently, it is required to survey the severity of tested voice in order to obtain accurate pitch estimates.

Use of Pulsed Dye Laser in the Treatment of Sulcus Vocalis

Objective The pulsed dye laser (PDL) has been shown to be effective in the treatment of hypertrophic scars and keloids in dermatology. On the basis of histopathologic similarities between sulcus vocalis and scar tissue and numerous reports on the treatment of laryngeal lesions, especially scar tissue, with PDL, we evaluated the efficacy of treating sulcus vocalis with PDL. We named this surgical procedure PDL glottoplasty. Study Design Case series with planned data collection. Setting A university-based, tertiary care medical center. Subjects and Methods This study was conducted on 25 patients diagnosed with sulcus vocalis by videostroboscopy at the Gangnam Severance Hospital Otorhinolaryngology Department between August 2006 and February 2012. Energy delivery was fixed at 0.75 Joules (J) per pulse, and each vocal fold was administered 60 to 110 pulses (average 72.5 pulses) during each procedure. Aerodynamic, stroboscopic, and acoustic voice analyses were performed pre- and postoperatively. Results Although assessment was necessarily subjective, our study indicated that vocal folds showed decreased stiffness and improved mucosal wave properties after treatment, resulting in improved vibration and dysphonia. In the objective assessments, most patients who underwent PDL glottoplasty showed improvement in several postoperative voice analysis indices. The differences between preoperative and some postoperative voice parameter indices were statistically significant. Conclusion We found PDL glottoplasty to be beneficial in the treatment of sulcus vocalis. Objective measurements of voice quality and normalization of vocal fold vibration improved after PDL treatment in most cases. Our results warrant further studies with larger numbers of participants and longer follow-up periods.

A polyethylene glycol grafted bi-layered polyurethane scaffold: preliminary study of a new candidate prosthesis for repair of a partial tracheal defect

The purpose of this study was to develop an artificial prosthesis for use in the reconstruction of a tracheal defect due to trauma, malignancy, stenosis, or other causes. Bi-layered porous-dense film polyurethane (PU) was manufactured for the main framework. Polyethylene glycol (PEG) was grafted onto the inner surface of the PU scaffold to act as a surfactant. The scaffold was transplanted into three beagles. An endoscopic examination was performed for the evaluation of the formation granulation tissue, to evaluate the status of the respiratory mucosa and the amount of crust at 1, 4, 8, and 12 weeks after surgery. A histological examination was also performed at 4, 8, and 12 weeks after surgery. All three beagles studied survived to the expected date. The endoscopic examination showed formation of granulation tissue; the crust was not very severe and the circular tracheal framework was well preserved. The histological examination showed that a large amount of fibrous tissue had grown through the pores of the porous scaffold. Pseudostratified columnar ciliated mucosa was also noted on the surface of scaffold, as visualized by scanning electron microscopy. The use of a bi-layered polyethylene grafted polyurethane scaffold is a good candidate prosthesis for tracheal reconstruction.

Phonatory outcome of 585 nm/pulsed-dye laser in the management of glottic leukoplakia

OBJECTIVE Vocal cord mucosectomy using pulsed-dye laser was assessed for its ability to completely remove lesions without deterioration of vocal quality in cases of vocal cord leukoplakia. To confirm the validity of a pulsed-dye laser, we retrospectively analyzed the treatment outcomes of patients who received surgery preceded by pulsed-dye laser and compared these with the outcomes of patients who received vocal cord mucosectomy using CO2 laser. METHODS Between February 2007 and June 2012, 36 patients were enrolled. Seventeen patients received vocal cord treatment with a CO2 laser and 19 patients received operation with a pulsed-dye laser. To evaluate voice status, acoustic wave form analysis and electroglottography were done, and voice handicap index was measured before and after the operation. RESULTS The entire lesion was removed in all patients. Compared to preoperative vocal parameters, the postoperative values for jitter were only improved in the pulsed-dye laser group. On stroboscopic findings, a diminution or lack of mucosal wave was observed in more CO2 laser cases than pulsed-dye laser cases. Significant improvement in voice handicap index results was only observed in the pulsed-dye laser group. CONCLUSION Although long-term results with more patients are required to establish the validity of pulsed-dye laser, this study confirmed the merits of pulsed-dye laser for the en-bloc removal of vocal cord leukoplakia and improved voice outcome.

Clinical Characteristics of Vocal Polyps With Underlying Sulcus Vocalis

OBJECTIVE This study aims to find a correlation between vocal fold polyps and sulcus vocalis and to investigate the character of such vocal fold polyps associated with sulcus vocalis. STUDY DESIGN Retrospective clinical research. METHODS A retrospective review of 280 patients who have been admitted and operated under general anesthesia for vocal fold polyps at a tertiary care medical center from March 2009 to July 2012 was performed. RESULTS The patients were classified into two groups. Group A (18 patients) was defined as patients who have been diagnosed with vocal polyps coexisting with sulcus vocalis. Group B (262 patients) was designated to the rest of the patients who have been solely diagnosed with vocal fold polyps. The prevalence of an underlying sulcus vocalis associated with vocal polyps in the studied population overall was 6.4% (18/280). Considering the recurrence rate of vocal fold polyps in each group, it was 16.7% (three patients) in group A and 3.1% (eight patients) in group B. In general, there was an improvement in the voice quality after the operation in both groups. The degree of improvement was less substantial in group A rather than group B. CONCLUSION When dealing with patients who have been diagnosed as vocal fold polyps, the possibility of coexisting sulcus vocalis should always be considered, and if diagnosed simultaneously, management of vocal polyps and sulcus vocalis must be sought for a better voice outcome and to reduce the chance of recurrence of vocal polyps.

Treatment of Hemorrhagic Vocal Polyps by Pulsed Dye Laser-Assisted Laryngomicrosurgery

Objective. Conventional surgical techniques of laryngomicrosurgery (LMS) on hemorrhagic vocal polyps are often difficult due to obscuration of the surgical field by inadvertent bleeding from the lesion, and there are often significant amounts of mucosal epithelium loss. Here, we introduce our surgical technique using pulsed dye laser (PDL), which can effectively resect the polyp with vocal fold mucosa preservation. Methods. Patients who were diagnosed with hemorrhagic vocal polyp and who were surgically managed using PDL from March 2013 to October 2014 were retrospectively reviewed. Preoperative and postoperative clinical outcomes and surgical findings were evaluated. Results. A total of 39 patients were treated with PDL-assisted enucleation LMS. The average age was 43.7 years (range 20–73), and there were 20 males and 19 females (17 professional voice users). In all cases, the hemorrhagic polyp was successfully enucleated after application of PDL, thereby preserving the overlying epithelium. Postoperative voice outcomes were favorable with clear preservation of the vocal fold mucosal wave. Conclusion. PDL-assisted enucleation LMS for the treatment of hemorrhagic vocal polyps can be a safe and effective surgical technique. It can be considered a promising treatment option for hemorrhagic vocal polyps.