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.

The effect of intraoperative transnasal humidified rapid-insufflation ventilatory exchange on emergence from general anesthesia in patients undergoing microlaryngeal surgery: a randomized controlled trial.

BACKGROUND: Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) has received extensive attention for its utility in tubeless anesthesia. Still, the effects of its carbon dioxide accumulation on emergence from anesthesia have not been reported. This randomized controlled trial aimed at exploring the impact of THRIVE combined with laryngeal mask (LM) on the quality of emergence in patients undergoing microlaryngeal surgery. METHODS: After research ethics board approval, 40 eligible patients receiving elective microlaryngeal vocal cord polypectomy were randomly allocated 1:1 to two groups, THRIVE + LM group: intraoperative apneic oxygenation using THRIVE followed by mechanical ventilation through a laryngeal mask in the post-anesthesia care unit (PACU), or MV + ETT group: mechanically ventilated through an endotracheal tube for both intraoperative and post-anesthesia periods. The primary outcome was duration of PACU stay. Other parameters reflecting quality of emergence and carbon dioxide accumulation were also recorded. RESULTS: Duration of PACU stay (22.4 ± 6.4 vs. 28.9 ± 8.8 min, p = 0.011) was shorter in the THRIVE + LM group. The incidence of cough (2/20, 10% vs. 19/20, 95%, P < 0.001) was significantly lower in the THRIVE + LM group. Peripheral arterial oxygen saturation and mean arterial pressure during intraoperative and PACU stay, Quality of Recovery Item 40 total score at one day after surgery and Voice Handicap Index-10 score at seven days after surgery were of no difference between two groups. CONCLUSIONS: The THRIVE + LM strategy could accelerate emergence from anesthesia and reduce the incidence of cough without compromising oxygenation. However, these benefits did not convert to the QoR-40 and VHI-10 scores improvement. TRIAL REGISTRATION: ChiCTR2000038652.

Transoral management of pharyngeal ballistics.

OBJECTIVE: To present a case of a ballistic foreign body in the pharynx after a gunshot wound to the maxillofacial area, an accompanying review of relevant literature, and our approach to management. METHOD: A 68-year-old male with no prior medical history presented to our trauma center with gunshot wounds to the left chin, left wrist, right chest, and sternum. A CT Angiogram of the neck revealed a bullet fragment left neck and additional fragment adjacent to the L hypopharynx at the level of the hyoid. The patient was taken to the operating room for direct laryngoscopy with foreign body removal and esophagoscopy. RESULTS: We document our workup and successful surgical removal of the pharyngeal ballistic foreign body via our video abstract, compiling preoperative imaging, intraoperative imaging, and video. Literature review of the subject accompanying our video abstract highlights the extensive complications that can occur from a retained foreign body in this area, supporting surgical removal of the foreign body if safely possible. CONCLUSION: Given the demonstrated feasibility and success of endoscopic foreign body removal from the pharyngoepiglottic space, in addition to overwhelming support for removal in the literature we recommend surgical extraction of ballistic foreign bodies located in the upper aerodigestive tract in stable patients to avoid early and long-term complications that can impact swallowing function, airway stability and the vital structures contained within the neck.

Microdebrider is less aerosol-generating than CO2 laser and cold instruments in microlaryngoscopy.

OBJECTIVE: COVID-19 spreads through aerosols produced in coughing, talking, exhalation, and also in some surgical procedures. Use of CO2 laser in laryngeal surgery has been observed to generate aerosols, however, other techniques, such cold dissection and microdebrider, have not been sufficiently investigated. We aimed to assess whether aerosol generation occurs during laryngeal operations and the effect of different instruments on aerosol production. METHODS: We measured particle concentration generated during surgeries with an Optical Particle Sizer. Cough data collected from volunteers and aerosol concentration of an empty operating room served as references. Aerosol concentrations when using different techniques and equipment were compared with references as well as with each other. RESULTS: Thirteen laryngological surgeries were evaluated. The highest total aerosol concentrations were observed when using CO2 laser and these were significantly higher than the concentrations when using microdebrider or cold dissection (p < 0.0001, p < 0.0001) or in the background or during coughing (p < 0.0001, p < 0.0001). In contrast, neither microdebrider nor cold dissection produced significant concentrations of aerosol compared with coughing (p = 0.146, p = 0.753). In comparing all three techniques, microdebrider produced the least aerosol particles. CONCLUSIONS: Microdebrider and cold dissection can be regarded as aerosol-generating relative to background reference concentrations, but they should not be considered as high-risk aerosol-generating procedures, as the concentrations are low and do not exceed those of coughing. A step-down algorithm from CO2 laser to cold instruments and microdebrider is recommended to lower the risk of airborne infections among medical staff.

Indirect laryngoscopic assessment for the diagnosis of difficult intubation in patients undergoing microlaryngeal surgery.

BACKGROUND: The aim of this study is to investigate the feasibility of using indirect laryngoscopy for the diagnosis of difficult intubations in patients who are undergoing microlaryngeal surgery. METHODS: In the pre-anesthetic examination the thyromental distance, sternomental distance, interincisor distance, neck circumference, modified Mallampati scores, and Wilson risk scores were measured. An otolaryngologist conducted an indirect laryngoscopic assessment. Direct laryngoscopic profiles were classified according to their Cormack-Lehane scores. RESULTS: Forty patients underwent microlaryngeal surgery. Their mean ages, neck circumferences, Cormack-Lehane scores of the patients who had intubation difficulties were statistically significantly higher than those who did not have intubation difficulties (p < 0.05). The significant differences between the indirect laryngoscopic assessment distributions of patients who either had or did not have intubation difficulty were assessed (p < 0.05). CONCLUSIONS: Indirect laryngoscopic assessment is a simple and valuable technique that can be used for the diagnosis of difficult intubation in patients who are undergoing microlaryngeal surgery.

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.

"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.

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.

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.

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.

Examining readmissions following outpatient microlaryngeal surgery.

Objective: The objective of this study was to examine readmissions following microlaryngeal surgery. It was hypothesized that airway surgical procedures would have higher rates of readmission. Design: Retrospective review. Methods: Outpatient microlaryngeal surgeries from May 1, 2018 to November 27, 2022 were reviewed. Readmissions related to the original surgery within a 30-day postoperative period were examined. Patient demographics, body mass index, American Society of Anesthesiologist class, comorbidities, type of surgery, ventilation techniques, and operative times were examined and compared. Results: Out of 480 procedures analyzed, 19 (4.0%) resulted in a readmission, 9 (1.9%) of which were for glottic stenosis management. Undergoing an airway procedure was significantly associated with a readmission (p = .002) and increased the odds of readmission by 5.99 (95% confidence interval [CI]: 2.22-16.16, p < .001). Current/former smoking status increased the odds of readmission by 4.50 (95% CI: 1.33-15.19, p = .016). Each additional minute of operating time increased the odds of readmission by 1.03 (95% CI: 1.00-1.05, p = .04). Conclusion: Readmissions from microlaryngeal surgery are seldom reported but nonetheless occur. Identifying factors that may place a procedure at risk for readmission can help improve surgical quality of care. Level of Evidence: 4.

Ultrafast Laser Microlaryngeal Surgery for In Vivo Subepithelial Void Creation in Canine Vocal Folds.

BACKGROUND/OBJECTIVES: Tightly-focused ultrafast laser pulses (pulse widths of 100 fs-10 ps) provide high peak intensities to produce a spatially confined tissue ablation effect. The creation of sub-epithelial voids within scarred vocal folds (VFs) via ultrafast laser ablation may help to localize injectable biomaterials to treat VF scarring. Here, we demonstrate the feasibility of this technique in an animal model using a custom-designed endolaryngeal laser surgery probe. METHODS: Unilateral VF mucosal injuries were created in two canines. Four months later, ultrashort laser pulses (5 ps pulses at 500 kHz) were delivered via the custom laser probe to create sub-epithelial voids of ~3 × 3-mm2 in both healthy and scarred VFs. PEG-rhodamine was injected into these voids. Ex vivo optical imaging and histology were used to assess void morphology and biomaterial localization. RESULTS: Large sub-epithelial voids were observed in both healthy and scarred VFs immediately following in vivo laser treatment. Two-photon imaging and histology confirmed ~3-mm wide subsurface voids in healthy and scarred VFs of canine #2. Biomaterial localization within a void created in the scarred VF of canine #2 was confirmed with fluorescence imaging but was not visualized during follow-up two-photon imaging. As an alternative, the biomaterial was injected into the excised VF and could be observed to localize within the void. CONCLUSIONS: We demonstrated sub-epithelial void formation and the ability to inject biomaterials into voids in a chronic VF scarring model. This proof-of-concept study provides preliminary evidence towards the clinical feasibility of such an approach to treating VF scarring using injectable biomaterials. LEVEL OF EVIDENCES: N/A Laryngoscope, 133:3042-3048, 2023.

A Retrospective Study to Assess the Accuracy of Frozen Sections in Laser Laryngeal Surgery.

OBJECTIVE: The basis of good vocal outcomes following Transoral Laser Microlaryngeal Cordectomy (TLMC) is the narrow margin that is oncologically accepted for the glottis. Our objective is to evaluate the reliability of frozen section (FS) compared to paraffin section (PS) during TLMC and during laser laryngeal surgery when an incisonal or excisional biopsy is being performed. METHODS: Retrospectively, records of 159 sequential patients who underwent CO2 laser laryngeal surgery with intraoperative FS were reviewed along with the final PS. Group A patients were TLMC patients where FS was utilized for free margin confirmation (42 specimens) and Group B patients were those in whom FS was performed for primary diagnosis (122 specimens). RESULTS: A total of 164 samples were included where specimens submitted for FS were also processed for PS. Concordance was observed in 156 samples, discordance in 8, with 4 cases belonging to each group. FS was reported as false negative in 5 and false positive in 3 cases. In Group A where FS was utilized for free margin confirmation, the sensitivity was found to be 60%, specificity and positive predictive value (PPV) 100%, and negative predictive value (NPV) 88.9%. In Group B where FS was performed for primary diagnosis, the sensitivity was found to be 98.4%, specificity 95.1%, PPV 95.2%, and NPV 98.3%. CONCLUSION: A 100% PPV of FS in group A suggests that positive FS margins during TLMC may be safely relied upon in making decisions to upgrade the type of cordectomy being performed. A NPV of 88.9% in group A suggests that despite a clear frozen margin report during TLMC, 11.1% of patients would need further treatment. A PPV of 95.2% in group B suggests that although FS analysis is important for guiding further management, decisions regarding major laryngeal surgery should not be undertaken based solely on FS.

A rare case of a laryngeal angiomyolipoma.

Laryngeal angiomyolipoma is a rare tumor with few reported cases in the literature. The case report explains a 62-year-old man who presents with dyspnea and found to have a laryngeal angiomyolipoma staining CD34 positive, but HMB45 and Melan-A negative.

Effects of Different Voice Rest on Vocal Function After Microlaryngeal Surgery: A Systematic Review and Meta-Analysis.

OBJECTIVES: To compare the results of a voice handicap index (VHI) scale and acoustic parameters in patients who underwent microlaryngeal surgery followed by either short-duration (voice rest for <7 days) or long-duration (≥7 days) voice rest. STUDY DESIGN: Systematic review and meta-analysis. METHODS: The PubMed, Embase, and Cochrane Library databases were systematically searched for articles published before March 1, 2021. Randomized controlled trials (RCTs) that measured the voice outcomes of patients after different durations and extents of postoperative voice restriction were included in the meta-analysis. RESULTS: Four RCTs comprising 112 patients were included in the quantitative meta-analysis. Compared with the long-duration voice rest group, the short-duration group exhibited comparable VHI scores (mean difference [MD], -7.01; 95% CI, -16.12 to 2.09; p = 0.13), maximum phonation time (MD, -2.58; 95% CI, -5.42 to 0.26; p = 0.07), and acoustic variables of jitter (MD, -1.25; 95% CI, -3.43 to 0.94; p = 0.26) and shimmer (MD, -0.79; 95% CI, -2.08 to 0.51; p = 0.24). Subgroup analysis for benign pathology and cold instruments studies demonstrated significantly better VHI scores (MD, -14.45; 95% CI, -26.19 to -2.72; p = 0.02 and MD, -15.98; 95% CI, -28.52 to -3.44; p = 0.01, respectively) in the short-duration group. CONCLUSIONS: The limited evidence does not demonstrate benefit in voice outcomes from long-duration voice rest and suggests potential unfavorable effects on compliance and quality of life, providing a rationale for short-duration voice rest after microlaryngeal surgery. More studies are required to determine the optimal duration and extent of postoperative voice rest. LEVEL OF EVIDENCE: 1 Laryngoscope, 133:154-161, 2023.

A case report of extramedullary plasmocytoma-rare pathology in the larynx.

Extramedullary plasmocytoma is a rare finding. The diagnosis is made by histological and immunohistochemical examination. Hematological evaluation is mandatory to rule out multiple myeloma. Radiotherapy is treatment of choice with good results.

Microlaryngeal Laser Surgery Using High-flow Nasal Ventilation at Two Oxygen Concentration Deliveries.

OBJECTIVES: Ventilation using 100% oxygenation creates a risk of fire during laser microlaryngeal surgery (MLS). The purpose of this study is to describe the technique of transnasal high-flow ventilation using laser safe (30%) oxygen conditions, measure the intraoperative real-time laryngeal oxygen concentration, and examine patient saturation status using this technique. METHODS: Prospective IRB approved study of patients undergoing tubeless laser MLS using high-flow nasal oxygenation. Delivered oxygen concentration was reduced from 100% to 30% before lasering using an oxygen-air blender then increased to 100% post-laser procedure. Outcome measures included time for laryngeal oxygen concentration to equalize to laser safe levels; time to, methods of and duration of rescue ventilation; and desaturation rates and apnoeic times at both 100% and 30% oxygen deliveries. RESULTS: Fifty patients were recruited (mean age = 47.4 years). Mean laryngeal oxygen concentration (%) at 100% and 30% deliveries was 98.46 and 31.45, respectively. Mean (SD) of laryngeal oxygen concentration equalization time to 30% (seconds) was 9.4 (3.69). At 30% oxygen delivery desaturation rate was faster and apneic time shorter compared with 100%. Eighteen patients required rescue (jet) ventilation and they had a faster apneic desaturation rate (%/minute) than patients not requiring rescue. Mean (SD) apneic time (minutes) at 30% delivery was 4.56 (2.25) and 4.41 (2.18) in rescue versus non-rescue groups respectively. BMI was the only significant predictor of desaturation rate at 30% oxygen delivery. CONCLUSION: It is possible to achieve a safe time window for use of laser during MLS using transnasal humidified high-flow ventilation by delivering 30% oxygen concentration. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:634-639, 2023.

Risk factors for postoperative vocal fold fibrosis following microlaryngeal surgery.

Objective: To analyze the risk factors for postoperative vocal fold fibrosis (PVF) in patients undergoing microlaryngeal surgery (MLS) for benign vocal fold lesions. Study Design: Retrospective study. Methods: We retrospectively included patients who had undergone MLS for vocal polyps, nodules, mucus retention cysts, fibrous mass, or Reinke's edema. Data on the patients' clinicodemographic characteristics and intraoperative findings were obtained by reviewing their clinical records. PVF was defined by the presence of an adynamic segment of membranous vocal folds or a marked reduction in mucosal wave amplitude on post-MLS (6 weeks) videolaryngostroboscopy. The risk factors for PVF were analyzed through univariate and multivariate logistic regressions. Results: This study included 89 patients, of whom 16 (18%) were given a diagnosis of PVF. A significantly increased incidence of PVF was noted in patients with fibrous mass (p < .01). The univariate analysis indicated that lesion attachment to the vocal ligament, prolonged surgical duration (>60 min), and symptom duration (>12 months) were significantly correlated with PVF (p < .05). The multivariate analysis confirmed that diagnosis of fibrous masses, lesion attachment to the vocal ligament and symptom duration are significant risk factors for PVF. Conclusion: PVF is more common in patients with fibrous masses. Lesions attachment to the vocal ligament and prolonged symptom duration appear to be other significant risk factors for PVF. Level of Evidence: 4.

High-flow Nasal Cannula versus Conventional Ventilation in Laryngeal Surgery: A Systematic Review and Meta-analysis.

High-flow nasal cannula (HFNC) is an emerging option for maintaining oxygenation in patients undergoing laryngeal surgery, as an alternative to traditional tracheal ventilation and jet ventilation (JV). However, the data on its safety and efficacy is sparse. This study aims to aggregate the current data and compares the use of HFNC with tracheal intubation and jet ventilation in adult patients undergoing laryngeal surgery. We searched PubMed, MEDLINE (Medical Literature Analysis and Retrieval System Online, or MEDLARS Online), Embase (Excerpta Medica Database), Google Scholar, Cochrane Library, and Web of Science. Both observational studies and prospective comparative studies were included. Risk of bias was appraised with the Cochrane Collaboration Risk of Bias in Non-Randomized Studies - of Interventions (ROBINS-I) or RoB2 tools and the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for case series. Data were extracted and tabulated as a systematic review. Summary statistics were performed. Meta-analyses and trial sequential analyses of the comparative studies were performed. Forty-three studies (14 HFNC, 22 JV, and seven comparative studies) with 8064 patients were included. In the meta-analysis of comparative studies, the duration of surgery was significantly reduced in the THRIVE (Transnasal Humidified Rapid-Insufflation Ventilatory Exchange) group, but the number of desaturations, need for rescue intervention, and peak end-tidal CO2 were significantly increased compared to the conventional ventilation group. The evidence was of moderate certainty and there was no evidence of publication bias. In conclusion, HFNC may be as effective as tracheal intubation in oxygenation during laryngeal surgery in selected adult patients and reduces the duration of surgery but conventional ventilation with tracheal intubation may be safer. The safety of JV was comparable to HFNC.