Photoangiolysis with the 445-nm Blue Laser and the Potassium-Titanyl-Phosphate Laser: A Comparison.

OBJECTIVES: Photoangiolytic lasers have yielded significant innovation in laryngeal surgery in the last 25 years. After the discontinuation of the potassium titanyl phosphate (KTP) laser, a novel 445-nm blue laser was developed. The optimal balance between a laser's desired tissue effects and collateral tissue damage is a major determinant of laser selection in microlaryngeal surgery. The shell-less incubation system for the chick chorioallantoic membrane (CAM) simulates the microvasculature of the human vocal fold and is useful for testing effects of laser settings and in simulated surgery. The aim of this study is to compare the tissue effects of the KTP and blue lasers using the shell-less CAM model. METHODS: The shell-less incubation system contains: polymethylpentene film (used as a culture vessel), calcium lactate and distilled water supplementations. By using this system, the chick chorioallantoic membrane (CAM) can be fully exposed with a good field for surgery simulation. The effects of the 2 lasers (532 nm KTP and 445 nm blue) were quantified at clinically relevant energy settings and laser distances from target. Measures included imaging real-time vascular reactions in the CAM model, post-procedure histologic analysis of CAM tissue and temperature changes. RESULTS: Vessel coagulation and rupture rates were less common with the blue laser compared with the KTP laser. Histologic analysis demonstrated less tissue disruption with the blue laser. Temperature changes were less with the blue laser. CONCLUSION: In this CAM model with specific conditions, the blue laser reveals less tissue damage than the KTP laser. Suitable working distance and power setting of the laser are necessary for desired tissue effects.Level of Evidence: Level 3.

Correlation Between the Effects of CO2 Laser and Histopathological Analysis in Vocal Cord Lesions: An Observational Study.

Lasers are based on the principle of light amplification by empowering atoms to store and emit light in a coherent form. Through their effect on tissues, lasers reduce hemorrhage allowing the surgeon to work in a clear field with precise removal of the tissues. Irradiation of the soft tissues by lasers produces thermal effects on the surrounding healthy tissues which can make histopathological examination difficult. Hence this study was done to find a correlation between adjustable parameters of CO2 laser and the extent of collateral thermal damage in the excised vocal cord lesions on histopathological examination and diagnosis. In this study, we enrolled 80 patients who were divided into 4 groups with different combinations of laser power and mode, used during transoral laser micro laryngeal surgery for the excision of vocal cord lesions and subsequent histopathological analysis to objectively measure the extent of thermal damage zone and subjectively assess histo-morphological effects of thermal damage in terms of grade of carbonization. The extent of the thermal damage zone is directly related to the power of the laser, but the mode of the laser had no relation with the thermal damage zone in our study. On subjective histo-morphological examination of excised lesions showed that both power and mode of laser have significant effects on tissue morphology. Continuous mode causes a significantly higher grade of carbonization as compared to the superpulsed mode of the laser. However, in our study it was seen that charring in no way affected the diagnosis in any of the biopsies examined whatever the power or mode of the laser used. The depth and width of the tissue thermal damage zone are mainly dependent upon the laser parameters (power and mode). Although considering the limitations of this study carried out in terms of sample size, it would be pertinent to mention here that further studies with larger cohorts need to be done to authenticate these results.

Successful Application of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange in a Case of Subglottic Stenosis.

We widely employ microlaryngeal surgery to treat diverse oropharyngeal and laryngeal conditions, but it presents challenges to shared airway management. This case report addresses the limitations of conventional techniques, such as tracheal intubation and jet ventilation, and explores the emerging interest in transnasal humidified rapid insufflation ventilatory exchange (THRIVE). While THRIVE offers advantages such as enhanced visualization and reduced airway trauma, its application is limited by the duration of apnea, with the literature referring to a maximum of 30 minutes of apnea. We present the successful application of THRIVE as the primary airway management technique in a patient undergoing a 55-minute dilation procedure for subglottic stenosis. Successful oxygenation was achieved, creating a tubeless field and improving visibility. The patient maintained oxygen saturation above 98%, demonstrating the effectiveness of THRIVE in managing prolonged apnea. Remarkably, intentional ventilation via a face mask at specific moments allowed extended apneic oxygenation without harmful carbon dioxide levels. This report complies with the growing evidence supporting the efficacy of THRIVE in providing extended apnea for tubeless surgery. The success demonstrated in our case highlights the feasibility and effectiveness of THRIVE in situations demanding prolonged apnea and complex airway management.

Randomized Controlled Trial of Awake Transnasal Laser-Assisted Surgery for Benign Laryngeal Lesions.

OBJECTIVE: To compare functional and cost-effectiveness of awake transnasal laser assisted-surgery versus microlaryngeal surgery for benign laryngeal lesions. METHODS: This was a prospective non-inferiority randomized controlled trial conducted from May 2021 to December 2022 at two tertiary referral hospitals in Hong Kong. Patients were block-randomized to receive either awake transnasal laser-assisted surgery or microlaryngeal surgery, with post-operative follow-up in a multidisciplinary voice clinic for 1-year. Primary outcome was Voice Handicap Index (VHI-30). Secondary outcomes included operation time, complications, length of stay, peri-operative discomfort, recurrence, and medical costs. RESULTS: Sixty-one patients were randomized to either awake transnasal laser-assisted surgery (n = 30) and microlaryngeal surgery (n = 31). Both groups had comparable demographics and laryngeal pathologies. Both groups showed significant improvement of VHI-30 score over time and had comparable post-operative VHI-30. Awake transnasal laser-assisted surgery group had a significantly shorter length of stay (0.5 vs. 1 day) and less throat discomfort (2 vs. 4) compared to microlaryngeal surgery group. Intraoperative complications were more common in microlaryngeal surgery group (14.3% vs. 0%). Otherwise, both groups had similar operative time and recurrence rate. Cost-analysis showed a significantly lower hospital cost for awake transnasal laser-assisted surgery (USD 3090) compared to microlaryngeal surgery group (USD 5120). CONCLUSION: Awake transnasal laser-assisted surgery was safe, functionally non-inferior, as measured by VHI-30, to microlaryngeal surgery in managing benign laryngeal lesions, while superior to microlaryngeal surgery in peri-operative discomfort and medical costs. LEVEL OF EVIDENCE: 2 Laryngoscope, 134:3732-3740, 2024.

"Pre and Post Treatment Comparison of S/Z Ratio in Benign Laryngeal Lesions".

Benign laryngeal lesions like vocal nodules, vocal polyp, vocal fold cysts are mostly found in patients complaining of change in voice. S/Z ratio has become the most frequently used clinical tool to assess phonatory mechanics. This study shows the pre-treatment and post-treatment comparison of S/Z ratios in patients with benign laryngeal lesions. To evaluate the outcome of microlaryngeal surgery in patients with benign laryngeal lesions using S/Z ratio as an outcome parameter. During this study, 65 patients with complaints of change in voice, with clinical evidence of benign laryngeal lesions underwent microlaryngeal surgery. Improvement in symptoms were measured preoperatively and postoperatively using S/Z ratio. This ratio was calculated by asking the patient to to maximally sustain 'S' and 'Z', repeated thrice. S/Z ratio was calculated by dividing the maximum duration for which /S/ was sustained by the maximum duration for which /Z/ was sustained. A ratio of more than 1.4 suggested a vocal cord disorder. There was statistically significant difference observed in S/Z ratio values, from pre-treatment to 6 months post-treatment, with P value 0.001. Pre and post treatment assessment of patients with benign vocal fold lesions showed significant improvement in S/Z ratio postoperatively. It is the simplest and a reliable objective method of voice assessment and can also be used in assessing the outcome of the treatment.

Bedside preoperative predictors of difficult laryngeal exposure in microlaryngeal surgery.

PURPOSE: Successful microlaryngeal surgery relies on an adequate laryngeal exposure. Recognizing the likelihood of challenging exposure prior to microlaryngeal surgery may assist in selecting the appropriate surgical approach and even prompt consideration of alternative treatment options. We aim to apply the mini-Laryngoscore, a preoperative assessment tool, to our study population and incorporate novel variables to optimize the prediction model. METHODS: This single-center prospective cohort study included 80 consecutive patients undergoing elective microlaryngeal surgery, from January 1, to June 30, 2023. Each patient underwent a presurgical evaluation of 15 parameters and an intraoperative scoring of the anterior commissure visualization. These parameters were assessed for their association with difficult laryngeal exposure, using multiple logistic regression analysis. We created a novel prediction model for DLE and compared it with the existing model, the mini-Laryngoscore. RESULTS: Out of 80 patients, 24 (30%) patients had difficult laryngeal exposure, including 3 cases (3.8%) in which visualization of the anterior commissure was not possible. A large neck diameter (OR, 1.4; CI 1.1-1.9) and the presence of upper teeth (OR, 8.9; CI 1.3-62.8) were independent risk factors for a difficult laryngeal exposure, while a larger interincisors gap was the only independent protector factor (OR, 0.3; CI 0.1-0.8). The logistic regression model combining these three independent risk factors displayed a high discriminative value AUC = 0.89 (CI 0.81-0.97). The predictive performance of the mini-Laryngoscore was 0.73 (CI 0.62-0.85). CONCLUSION: Combining two parameters from the mini-Laryngoscore (upper jaw dental state and interincisors gap distance) with neck circumference measurement can accurately predict the risk of difficult laryngeal exposure.

Comparison of Angiolytic Effects Between the 445-nm Blue Laser and 532-nm Pulsed KTP Laser.

OBJECTIVE: This study aimed to compare the selective absorption of the 445-nm Blue laser (BL) and the 532-nm pulsed potassium-titanyl-phosphate (KTP) laser by blood vessels. METHODS: Thirty-six chicken eggs at day 14 of incubation were dissected to expose the chick chorioallantoic membrane (CAM). Third-order vessels of the CAM were identified and irradiated using BL and KTP lasers using various settings at a laser-to-vessel distance of 3 mm using 0.4 mm fiber size. In total, 494 vessels segments were irradiated. Mean (standard deviation) number of irradiations for each setting was 26.0 (4.6), range from 15 to 39. Outcome measures included ablation rate (AR) and rupture rate (RR). RESULTS: The two lasers were compared for AR and RR at long and medium pulse width (PW) associated with different power levels. At long PW (above 100 ms), BL showed significantly higher AR than KTP at high energy (600 mJ/pulse) and low energy (400 mJ/pulse); they did not show different AR and RR at medium energy levels (500 mJ/pulse). Using medium PW settings plus high and medium energy levels, BL and KTP showed relatively high AR and did not significantly differ in performance. However, at medium PW plus low energy (400-450 mJ/pulse), KTP showed significantly higher AR compared to BL. CONCLUSION: At long PW, BL appeared to show higher AR than KTP at high or low energy levels, but they showed equivalent performance at medium energy. At medium PW, both performed similarly from high to medium energy, but KTP appeared to perform better than BL at lower energy settings. LEVEL OF EVIDENCE: NA Laryngoscope, 134:3220-3225, 2024.

Rethinking Perioperative Antibiotic Prophylaxis for Low-Risk Head and Neck Procedures.

OBJECTIVE: For true clean-contaminated head and neck procedures, the literature supports ≤24 hours of perioperative antibiotics. However, there are certain otolaryngology procedures with low surgical site infection (SSI) risk for which there is negligible benefit from antibiotic prophylaxis. The objective of this evaluation was to describe antibiotic use and adherence to evidence-based institutional guidelines in low-risk head and neck procedures. METHODS: This was a single-center, retrospective cohort study of patients undergoing low-risk clean-contaminated head and neck procedures wherein antibiotic prophylaxis was not indicated, based on evidence-based institutional guidelines. RESULTS: Among the 291 included patients, perioperative antibiotics were unnecessarily administered in 29% of patients. Among patients who received antibiotics, 76% received preoperative antibiotics and 41% received postoperative antibiotics, for a median duration of 7 days. There were no significant differences in SSIs, mortality, and length of stay for those receiving perioperative antibiotics versus those not receiving perioperative antibiotics. CONCLUSION: These data highlight the need for antibiotic stewardship interventions and partnerships between antibiotic stewardship teams and surgical services.

Seguridad y efectividad de la ventilación a chorro con frecuencias ventilatorias convencionales para microcirugía laríngea electiva / Safety and effectiveness of jet ventilation with conventional ventilatory frequencies for elective microlaryngeal surgery

Introducción: La ventilación al paciente durante la microcirugía laríngea confronta varios problemas. La ventilación a chorro tipo jet con frecuencias ventilatorias convencionales permite usar catéteres endotraqueales de pequeño diámetro para aportar volúmenes adecuados de oxígeno y proporciona mejores condiciones operatorias que el método tradicional. Objetivo: Evaluar la seguridad y efectividad de la ventilación jet con frecuencias ventilatorias convencionales para microcirugía laríngea electiva en comparación con la ventilación convencional. Métodos: Se realizó un estudio comparativo, a simple ciego, aleatorizado y paralelo. Se trabajó con un prototipo de dispositivo de ventilación jet con permiso de uso excepcional en seres humanos (autorización excepcional No: 004/17 para realización de estudio piloto, con fecha 2 de agosto de 2017, conferido por el CECMED). Se utilizó un grupo estudio de 45 pacientes (grupo E) y se comparó con un grupo control (grupo C) de 15 pacientes ventilados mediante el método tradicional. Resultados: La oxigenación resultó superior dentro del grupo E. El grupo C requirió eventualmente de extubación, apnea transitoria y reintubación, lo que repercutió en contra de la integridad anatomofisiológica de los pacientes, del campo operatorio y la docencia. Fue evidente una mayor estabilidad hemodinámica entre los sujetos del grupo E. Las presiones intrapulmonares producidas por la ventilación jet no provocaron lesiones ni repercusión clínica evidentes. Conclusiones: Aplicar la ventilación a chorro con frecuencias ventilatorias convencionales fue seguro y efectivo. Por primera vez se obtienen experiencias de utilización de un método de ventilación jet en el país. El grupo en el que se aplicó la ventilación convencional sufrió complicaciones más frecuentes y peligrosas. Es necesario asimilar las tecnologías de ventilación jet para elevar la calidad de la atención médica en tiempos de paz, de guerra o desastres, en contextos electivos, o emergentes como el desafío de una vía respiratoria difícil(AU)

Introduction: Ventilation to the patient during microlaryngeal surgery confronts several problems. Jet ventilation with conventional ventilatory frequencies allows the use of small diameter endotracheal catheters to provide adequate oxygen volumes and provide better operating conditions than the traditional method. Objective: To evaluate the safety and effectiveness of jet ventilation with conventional ventilatory frequencies for elective microlaryngeal surgery in comparison to conventional ventilation. Methods: A comparative, single-blind, randomized and parallel study was performed. It was used a prototype of jet ventilation device with an exceptional use permit in humans (exceptional authorization No: 004/17 for conducting a pilot study, dated August 2, 2017, conferred by the CECMED). A study group of 45 patients (group E) was used and compared with a control group (group C) of 15 patients using the traditional ventilation method. Results: Oxygenation was higher in group E. Group C eventually required extubation, transitory apnea and reintubation, which impacted against the anatomophysiological integrity of patients, the operative field and teaching. A greater hemodynamic stability was evident among the subjects of group E. The intrapulmonary pressures produced by jet ventilation did not cause obvious injuries or clinical repercussions. Conclusions: Applying jet ventilation with conventional ventilatory frequencies was safe and effective. For the first time, experiences of using a jet ventilation method in the country were obtained. The group in which conventional ventilation was applied suffered more frequent and dangerous complications. It is necessary to assimilate jet ventilation´s technologies to raise the quality of medical attention in times of peace, war or disasters, in elective or emerging contexts as the challenge of a difficult airway(AU)

A Case of Bradycardia due to Vagal Reflex during Laryngeal Microsurgery / 대한이비인후과학회지

Laryngeal microsurgery has been used popularly for phonosurgery. Sometimes, this procedure is complicated by cardiovascular changes due to insertion of laryngosope. Tachycardia and elevation of blood pressure are common but bradycardia induced by vagal reflex is very rare. The authors report the case of severe bradycardia induced by vagal reflex experienced during laryngeal microsurgery with a review of the literature.

Laryngeal Tiririt (Bridge): For microlaryngeal surgery shake

Objective: To design an instrument for steadying instrument handling during microlaryngeal surgery using an operating laryngoscope. Method: Our device design takes its cue (pun intended) from professional billiards players like our very own Efren "Bata" Reyes. The laryngeal tiririt (bridge or rake) draws inspiration from the billiards bridge (locally known as tiririt) used to extend the player's reach when the cue ball is too far to make an accurate shot. Setting: The laryngeal tiririt was used and tested by senior residents in microlaryngeal surgeries done in our institution. Result: The laryngeal tiririt greatly improved the accuracy required in laryngeal surgeries without adding up huge set up or expensive equipment. (Author)

The Effects of Preoperative Sprayed 10% Lidocaine on the Hemodynamic Response during Suspension Microlaryngeal Surgery / 영남의대학술지

PURPOSE: It is well known that suspension microlaryngeal surgery produces marked increases in arterial blood pressure and heart rate. In this study, we evaluated the effects of 10% lidocaine preoperatively sprayed for attenuation of the perioperative hemodynamic response during suspension microlaryngeal surgery. MATERIALS AND METHODS: Fifty American Society of Anesthesiologists (ASA) class 1 patients scheduled for excision of a vocal polyp by suspension laryngoscopy were randomly divided into two groups (n=25 for each group). They were intubated without 10% lidocaine spray (control group) or given 1.5 mg/kg of 10% lidocaine sprayed onto the pharyngolaryngeal and intratracheal sites 90 sec prior to intubation (10% lidocaine group). Anesthesia was maintained using desflurane in O2/N2O 50%. The arterial blood pressure and heart rate were measured at preinduction (T0), 1 min (T1), 3 min (T2), 5 min (T3) after tracheal intubation, and 1 min (T4), 3 min (T5), 5 min (T6) and 10 min (T7) after the suspension laryngoscopy. RESULTS: In the 10% lidocaine group, the arterial blood pressure and heart rate at 1 (T1), 3 (T2) min after tracheal intubation and 1 (T4), and 3 (T5) min after suspension laryngoscopy were lower than the same measurements in the control group. CONCLUSION: 10% lidocaine sprayed onto the pharyngolaryngeal and intratracheal sites before intubation was an effective method for attenuation of the perioperative hemodynamic response during suspension microlaryngeal surgery.

Microlaryngeal surgery for removing the fibrous noduls of the vocal cord

It is a radical technique. With delicate modified instruments, this technique can improve considerably the function because of the advances in technology that emphasize mucosal preservation

Vocal Dynamic Studies before and after Laryngeal Microsurgery / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Perceptual acoustic measures are most often used to judge the outcomes and the objective analysis of phonosurgical results before and after the microlaryngeal surgery. However, they have rarely been reported in this country. The purpose of this study is to analyze aerodynamic and acoustic results before and after microlaryngeal surgery and to analyze the differences of the prognosis of various benign vocal cord lesions. MATERIALS AND METHODS: At Inha University Hospital, from June 1996 to August 1998, 245 microlaryngeal surgeries were done. Malignant lesions were excluded. And 118 (54 females and 64 males) out of 245 patients were followed up after the surgery: the acoustic and the aerodynamic studies before and 8 weeks after microlaryngeal surgery for benign lesions: vocal polyp, vocal nodule, Reinke's edema, intracordal cyst and hyperkeratosis. Seven measurements were performed: fundamental frequency, jitter, shimmer, noise to harmonic ratio as the acoustic analysis, maximal phonation time, mean flow rate and subglottal pressure as the aerodynamic analyses. RESULTS: Postoperative acoustic and aerodynamic data of vocal polyp, vocal nodule, Reinke's edema and intracordal cyst were improved, but those of hyperkeratosis were not improved. CONCLUSION: By comparing the acoustic and aerodynamic data before and after the microlaryngeal surgery, postoperative vocal function was defined more accurately and objectively. Jitter, shimmer, and MFR might be meaningful parameters accessing the quantitative changes in vocal quality before and after the microlaryngeal surgery.

Acoustic Analysis of Benign Vocal Cord Lesions: Before and after Microlaryngeal Surgery / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Benign vocal cord lesions that are not responsive to medical and/or speech therapy are often treated by microlaryngeal surgery. The purpose of this study is to measure selected acoustic parameters to document quantitative changes in vocal quality before and after microlaryngeal surgery and to analyze differences of prognosis for various benign vocal cord lesions, such as vocal cord polyp, vocal cord nodule, and Reinke's edema. MATERIALS AND METHODS: The authors used a computerized acoustic analysis program (CSL-MDVP) to measure mean fundamental frequency (Fo), jitter, shimmer, and noise to harmonics ratio (NHR) from voice samples of selected patients who had benign vocal cord lesions before and after at least 10 weeks of surgery. RESULTS: The values of Fo and NHR showed no significant difference in all three groups. There was significant improvement in nodule regarding jitter. Also, there was significant improvement in the vocal cord polyp regarding jitter and shimmer. CONCLUSION: Jitter and shimmer will be effective acoustic parameters in documenting the quantitative changes in vocal quality before and after microlaryngeal surgery.