This is a prospective randomised controlled trial conducted at two tertiary referral hospitals in Hong Kong to compare the clinical and functional outcomes of office-based awake transnasal laser-assisted laryngeal surgery (TNLS) under local anesthesia to traditional microlaryngeal surgery for vocal cord cyst under general anesthesia.
The aim of the study is to prospectively compare the functional and clinical outcomes of TNLS under local anesthesia and MLS under general anesthesia in managing vocal cord cysts. Office-based awake transnasal laser-assisted surgery (TNLS) has been gaining popularity in treating different laryngeal lesions, with the advantages of avoiding general anesthetic risks and minimizing healthcare-related costs. In addition, the general waiting time for surgeries under general anesthesia in public hospitals is getting longer due to the increasing population and limited resources. The investigators have recently conducted a novel randomized controlled trial in 2021-2022 comparing the functional and cost-effectiveness of traditional microlaryngeal surgery (MLS) under general anesthesia and TNLS for benign laryngeal lesions (vocal cord polyps, nodules, cysts, granuloma and Reinke's edema), and found that TNLS was superior to MLS in terms of length of stay, intraoperative complications, perioperative throat discomfort and hospital costs; while it was equivalent to MLS in terms of functional outcome, operative time and recurrence rate. However, since the previous study's main goal was to compare TNLS to MLS in a macroscopic perspective in terms of functional outcomes and cost-effectiveness, it had included a wide variety of benign laryngeal lesions, and different vocal cord lesions may respond differently to laser surgery. Vocal cord cyst is a fluid-filled sac inside the vocal cord, with 2 subtypes: 1) Epidermoid cyst due to epithelial inclusion 2) Mucous retention cyst due to glandular ductal obstruction. Vocal cord cysts typically do not resolve with voice therapy, and are traditionally excised with microlaryngeal surgery with microflap technique or marsupialization. In our previous RCT study, subgroup analysis did not show a significant difference of vocal cord cyst recurrence in both TNLS and MLS group. However, the investigators' cohort had a higher overall vocal cord cyst recurrence rate (13.8%) compared to historic cohort rate of 2.2-8.7% , which may be accounted by that the vocal cord cysts were ablated and marsupialized instead of removed in the TNLS group. Nevertheless, a recent case series by Gao and colleagues showed a good functional outcome of awake KTP-laser marsupialization in selected cases. A larger cohort is warranted to compare TNLS to MLS for vocal cord cyst. Therefore, the investigators would like to conduct a randomized controlled trial to compared tradition MLS surgery to TNLS, with hypothesis that TNLS would be non-inferior to traditional microlaryngeal surgery in benign laryngeal lesions, and with its additional benefits on minimization of anesthetic risks and hospital expenses, hopefully to expand its further application.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
54
For TNLS, patients are admitted to the day center on the same morning or afternoon of the surgery with fasting prior 6 hours. After local anesthesia application, a 445nm blue laser is introduced via a working channel of bronchoscope and laser ablation of vocal cord cyst is performed. During the operation, patient will receive continuous SpO2 monitoring with regular blood pressure monitoring. After the procedure, patients are kept nil-by-mouth for 2 hours until anesthesia wears off, meanwhile with close observation in day ward with continuous SpO2 monitor for 1 hour. Patients will be discharged on the same day of the procedure, with voice rest for 3 days.
For traditional MLS under general anesthesia, after general anesthesia and intubation with microlaryngeal tube, the patient would be positioned on head-ring support for better alignment and access to glottis. A laryngoscope will be inserted transorally under direct vision and suspended. Vocal cord cysts are visualized with microscope, and removed with microsurgery instruments with microflap technique and sent for routine section. After the surgery, the patient is kept nil-by-mouth until fully awake, and is discharged on same day or the next day depending on the post- operative recovery. Patient will be discharged with voice rest for 3 days.
The Chinese University of Hong Kong
Hong Kong, Hong Kong
Voice-Handicap Index (VHI-30)
The primary outcome was to compare the pre- and post-operative Voice-Handicap Index 30 (VHI-30) of TNLS and MLS groups. The VHI-30 is a 30-item self-administered questionnaire, with score range from 0 to 120, and a score of 120 meaning worst voice score. It has been shown to be a reliable measure for voice treatment outcome. It consists of three subscales, namely physical, functional and emotional. It provides an overall measurement of a person's vocal function and how it influences a person's everyday functioning and experience.
Time frame: From enrolment to post-operative 1year
Perceptual evaluation of voice
Perceptual evaluation of voice using the GBRAS scale, in which patients would be required to produce sustained vowel and connected speech voice samples. Score range from 0 to 15, with 15 being the worst score. Two experienced speech-language pathologists blinded to the patient's information would rate the audio recordings.
Time frame: From enrolment to post-operative 1year
Acoustic voice analysis - Noise-to-Harmonic ratio (NHR)
Acoustic voice analysis will be performed using PRATT program; Noise-to-Harmonic ratio refers to the ratio between periodic and non-periodic components of a speech sound. A lower NHR score may indicate a worse voice outcome.
Time frame: From enrolment to post-operative 1year
Acoustic voice analysis - Jitter
Acoustic voice analysis will be performed using PRATT program; Jitter refers to variation of voice frequency.
Time frame: From enrolment to post-operative 1year
Acoustic voice analysis - Shimmer
Acoustic voice analysis will be performed using PRATT program; Shimmer refers to variation of intensity of the voice.
Time frame: From enrolment to post-operative 1year
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Aerodynamic measure of voice
Aerodynamic measure, maximal phonation time (MPT) would be measured by instructing patients to phonate /a:/ sound for as long as possible after maximal inspiration, at a spontaneous, comfortable pitch and loudness level, for three consequent trials.
Time frame: From enrolment to post-operative 1year
Visual analog scale (VAS)
In VAS, patients would be asked to self-rate their voice quality on a visual analog scale of 0 (best) to 10 (worst).
Time frame: From enrolment to post-operative 1year
Videostroboscopy - Mucosal wave pattern
Videostroboscopy would be conducted on all patients to look for any impaired mucosal wave form.
Time frame: From enrolment to post-operative 1year
Videostroboscopy - Vocal fold closure
Videostroboscopy would be conducted on all patients to compare the degree of vocal fold closure.
Time frame: From enrolment to post-operative 1year
Procedure-oriented outcomes - Reoperation
Comparison of the rate of reoperation for recurrence vocal cord cyst between two groups.
Time frame: From perioperative period to post-operative 1 year
Procedure-oriented outcomes - Disease recurrence
Comparison of the rate of vocal cord cyst recurrence between two groups.
Time frame: From perioperative period to post-operative 1 year
Procedure-oriented outcomes - Length of hospital stay
Comparison of the length of hospital stay (number of day) between two groups.
Time frame: From perioperative period to post-operative 1 year
Procedure-oriented outcomes - Surgical complications in Clavien-Dindo classification
Clavien-Dindo classification is a commonly used surgical complication grading system, from grade I-V with grade V indicating worst outcome (death).
Time frame: From perioperative period to post-operative 1 year
Procedure-oriented outcomes - Completeness of lesion removal
Indicates if the vocal fold pathology has been completely removed
Time frame: From perioperative period to post-operative 1 year
Procedure-oriented outcomes - Operation time
Comparison of the operation time between two groups in terms of minute.
Time frame: From perioperative period to post-operative 1 year
Patient-oriented outcomes
Patient-oriented outcomes included peri-operative throat, nose, and overall discomfort in visual analogue scale, a 10-point scale with 0 (least uncomfortable) to 10 (most uncomfortable).
Time frame: Perioperative period
Medical costs
Medical costs of both interventions would be also calculated respectively, including costs for inpatient hospital stay, medical staff, operating theater and consumable.
Time frame: From enrolment to post-operative 1year