Thyroid Cartilage Plane VS Superior Laryngeal Nerve Space Block in Awake Tracheal Intubation

Thyroid Cartilage Plane Versus Superior Laryngeal Nerve Space for Ultrasound-guided Superior Laryngeal Nerve Block in Awake Tracheal Intubation: a Randomised Non-inferiority Clinical Trial

The aim of this clinical trial is to compare the effectiveness and safety of ultrasound-guided thyroid cartilage plane approach with the superior laryngeal nerve space approach for superior laryngeal nerve block in awake tracheal intubation. Patients were randomized into the thyroid cartilage plane block group (T group) or the superior laryngeal nerve space block group (C group). In Group T, bilateral thyroid cartilage plane block was performed under ultrasound with thyroid cartilage as the landmark, and local anesthetic was injected on the surface of the thyroid cartilage. In Group C, local anesthetic was injected into the space between the thyrohyoid membrane and muscle groups above.

We aim to evaluate whether the thyroid cartilage plane approach is not inferior to the superior laryngeal nerve space approach for ultrasound-guided superior laryngeal nerve block in awake tracheal intubation

Study Overview

• Status: Not yet recruiting
• Conditions: Superior Laryngeal Nerve Block
• Intervention / Treatment: Procedure: Ultrasound-guided bilateral Superior Laryngeal Nerve Space Block; Procedure: Ultrasound-guided bilateral Thyroid Cartilage Plane Block

Detailed Description

After entering the operation room, ECG, SPO2, and invasive blood pressure were monitored. Sedation was facilitated. The proper anaesthesia depth was maintained at 60-80 using the bispectral index. Additionally, 0.5 mg of Penehyclidine Hydrochloride was injected intravenously once the venous access was established. 100% oxygen 4 L min-1 was administered with a nasal cannula throughout the procedure. All patients received topical pharyngeal anesthesia using lidocaine spray. We used a 5-12 MHz linear probeto perform bilateral block. The probe was placed parasagittally to locate the thyroid cartilage and superior laryngeal nerve space. After identification of related structure, we advanced a 22-gauge needle medial to the transducer at the upper half of the thyroid cartilage laminae until it touched the laminae or superior laryngeal nerve space using the out-of-plane technique. The correct location of the needle tip in the fascial deep to the muscle groups was confirmed by injecting 0.5-1 ml saline. A total of 2% lidocaine 2.5 ml was administered after negative aspiration bilaterally. "Spray-as-you-go" technique guided by a fiberoptic bronchoscope was performed to the tracheal with 5 ml of 2% lidocaine. After airway anesthesia, intubation completed.

The primary outcome was the proportion of acceptable intubation conditions (AIC). Secondary outcomes were the performance time, Ramsay sedation score, the patient's cough condition, comfort score, and tracheal tube tolerance score and other perioperative complications including airway hemorrhage and superior laryngeal nerve damage.

• Study Type: Interventional
• Enrollment (Estimated): 94
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tao Shan; Phone Number: +8618852095135; Email: 858727933@qq.com
• Study Contact Backup: Name: Ying Zhang; Phone Number: +8615380998716; Email: 1070434273@qq.com

Study Locations

• China
  • Jiangsu
    • Nanjing, Jiangsu, China, 210006
      • Nanjing First Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Patients scheduled for awake tracheal intubation under general anesthesia.
2. Patients with difficult airways (e.g., limited cervical spine mobility, full stomach, partial airway obstruction, craniofacial deformities or trauma, micrognathia, mouth opening <3cm, Mallampati III or IV classification) posing challenges for mask ventilation or intubation.
3. Age between 18 and 85 years old.
4. Gender is not restricted.
5. ASA classification of I - III.

Exclusion Criteria:

1. Cardiovascular dysfunction or arterial aneurysms.
2. Mental or neurological disorders or concomitant arterial aneurysms.
3. Infection at the puncture site.
4. Allergy to local anesthetics.
5. Continuous use of antiplatelet or anticoagulant medications preoperatively.
6. Hoarseness or coughing while drinking water.
7. Bronchial asthma.
8. Participation in other clinical trials within the previous 3 months before enrollment 9.r current participation in other clinical trials.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Superior Laryngeal Nerve Space Block Group (C Group); All patients received topical oral and pharyngeal anesthesia using 2.4% lidocaine spray. The pharyngeal surface was sprayed twice, with each spray lasting one second, and repeated after a 5-minute interval. Under ultrasound guidance, the needle was advanced step by step into the potential space between the relevant muscle groups and the thyrohyoid membrane. When the needle tip contacted the surface of the thyrohyoid membrane and slightly penetrated the submembranous tissue, negative aspiration was confirmed, and 2.5 mL of 2% lidocaine was injected into the space on each side. Subsequently, performing fiberoptic bronchoscope-guided subglottis and tracheal surface topical anesthesia using 5ml of 2% lidocaine. After completing surface anesthesia, performing fiberoptic bronchoscope-guided tracheal intubation.	Procedure: Ultrasound-guided bilateral Superior Laryngeal Nerve Space Block; Use a SonoSite high-frequency linear array transducer (5-13 MHz, SonoSite, USA). Placing the transducer parallel to the spine on one side of the neck, ensuring clear visualization of the superior laryngeal nerve space under ultrasound. Using the out-of-plane technique to visualize the needle insertion path and tip. 2% lidocaine 2.5ml was injected into the space between the thyrohyoid membrane and muscle groups above.
Experimental: Thyroid Cartilage Plane Block Group (T Group); All patients received topical oral and pharyngeal anesthesia using 2.4% lidocaine spray. The pharyngeal surface was sprayed twice, with each spray lasting one second, and repeated after a 5-minute interval. Ultrasound-guided bilateral Thyroid Cartilage Plane Block is performed using the thyroid cartilage as an anatomical landmark. 2.5ml of 2% lidocaine is injected on the surface of the thyroid cartilage each side. Subsequently, performing fiberoptic bronchoscope-guided subglottis and tracheal surface topical anesthesia using 2% lidocaine 5ml. After completing surface anesthesia, performing fiberoptic bronchoscope-guided tracheal intubation.	Procedure: Ultrasound-guided bilateral Thyroid Cartilage Plane Block; Use a SonoSite high-frequency linear array transducer (5-13 MHz, SonoSite, USA). Placing the transducer parallel to the spine on one side of the neck, ensuring clear visualization of the thyroid cartilage under ultrasound. Using the out-of-plane technique to visualize the needle insertion path and tip. Once the needle tip contacts the cranial half of the thyroid cartilage, injecting 2.5ml of 2% lidocaine on the surface of the thyroid cartilage each side.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The proportion of patients with acceptable intubation conditions (AIC)	The evaluation of the intubation condition was based on the Cormack-Lehane classification, vocal cord movement, 5-point reaction scale, and severity of coughing. Clinically, AIC was defined when each part was scaled to Grade 1 or Grade 2. The proportion of AIC = number of participants with AIC/number of participants who received ATI in each group.	Upon intubation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurrences of sore throat and lowered pitch	Pharyngeal pain and decreased vocal tone are used to assess postoperative complications of neural blockade.	Post-extubation,24 hours after surgery
Quality of airway anesthesia	The quality of airway anesthesia assessed on a 5-point scale,Quality of airwayanesthesia was graded as: 0=no coughing or gagging in response to intubation, 1=mild coughing and/or gaggingthat did not hinder intubation, 2=moderate coughing and/or gagging that interfered minimally with intubation,3=severe coughing and/or gagging that made intubation difficult and 4=very severe coughing and/or gaggingthat required additional local anesthetic and/or change in technique.The lower grade means a better quality of airway anesthesia.	Upon intubation
Mean Arterial Pressure	Stable blood pressure indicates a good neural blockade effect.	T0: upon entry to the operating room,T1: before insertion of the tracheal tube,T2: immediately after tracheal tube insertion,T3: 5 minutes after successful intubation
Heart Rate	Time Frame: T0: upon entry to the operating room,T1: before insertion of the tracheal tube,T2: immediatelyafter tracheal tube insertion,T3: 5 minutes after successful intubation	T0: upon entry to the operating room,T1: before insertion of the tracheal tube,T2: immediately after tracheal tube insertion,T3: 5 minutes after successful intubation
Ramsay Sedation Score	The Ramsay Sedation Score is as follows: 6 points for unarousable, 5 points for slow response to stimulus, 4points for asleep but easily aroused, 3 points for quiet and cooperative with orientation, 2 points for asleep,anxious, restless, and 1 point for asleep, agitated, and restless. Satisfactory sedation falls within 2-4 points,while oversedation is indicated by 5-6 points.	T0: upon entry to the operating room,T1: before insertion of the tracheal tube,T2: immediately after tracheal tube insertion,T3: 5 minutes after successful intubation
The number of patients with lowered pitch	A lowered pitch might indicate a good neural blockade effect.	Before intubation
The time needed for blockade procedure	The neural blockade procedure time reflects the ease of the operation, with a shorter time indicating a simpler neural blockade procedure.	From ultrasounography localization to completion of local anesthetic administration
Record coughing in patients when the fiberoptic bronchoscope touches the glottis	The patient's coughing upon contact of the fiberoptic bronchoscope with the vocal cords before intubation reflects the effectiveness of neural blockade. A lower degree of coughing indicates a better neural blockadeeffect. 1 point for no response, 2 points for mild cough, 3 points for severe cough.	Before intubation
The tolerance score after the tube insertion	The tolerance of the tube reflects the patient's tolerance to awake tracheal intubation. A higher level of tolerance indicates a better neural blockade effect. 3 points for severe resistance requiring immediate general anesthesia, 2 points for restlessness and mild resistance, 1 point for cooperation.	Five minutes after successful intubation
Adverse reactions such as coughing and nausea/vomiting	The lower the incidence of coughing, nausea, and vomiting, the better the neural blockade effect.	During intubation
Total procedure time needed for awake intubation	The total procedure time reflects the ease of the operation, with a shorter time indicating a simpler procedure.	From the initiation of topical anesthesia to the accomplishment of tracheal intubation
Airway hemorrhage or nerve damage	Observation of bleeding of the laryngeal mucosa via fiberoptic bronchoscope or observation of bloody secretions via coughing or suction	During intubation

Collaborators and Investigators

• Sponsor: Nanjing First Hospital, Nanjing Medical University
• Investigators: Principal Investigator: Tao Shan, Nanjing First Hospital, Nanjing Medical University

Study record dates

Study Major Dates

• Study Start (Estimated): March 2, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2027

Study Registration Dates

• First Submitted: February 2, 2026
• First Submitted That Met QC Criteria: February 2, 2026
• First Posted (Actual): February 9, 2026

Study Record Updates

• Last Update Posted (Actual): February 9, 2026
• Last Update Submitted That Met QC Criteria: February 2, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Nerve block; Difficult airway; Superior Laryngeal Nerve; Awake tracheal intubation; Thyroid Cartilage plane; Superior laryngeal nerve space
• Other Study ID Numbers: KY20260108-04

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No