Clinical Efficacy and Peripheral Ultrasound Mechanism of Trigger Point Bloodletting Therapy for Primary Trigeminal Neuralgia

Study on Clinical Efficacy and Peripheral Ultrasound Mechanism of Trigger Point Bloodletting Therapy for Primary Trigeminal Neuralgia

This randomized controlled trial integrates baseline observational ultrasound analysis to assess the clinical efficacy of trigger point bloodletting therapy for primary trigeminal neuralgia and explore peripheral ultrasound mechanisms of trigger point lesions and treatment response. Eligible subjects are adults aged 18-75 with unilateral classic primary trigeminal neuralgia and confirmed trigger points in the orbicularis oris muscle.

The primary research question is whether 8-week trigger point bloodletting achieves a greater reduction in Brief Pain Inventory-Facial total score (primary endpoint) than oral carbamazepine. Secondary questions explore inter-side differences in orbicularis oris thickness, elasticity and microvascular perfusion, correlations between ultrasound biomarkers, pain severity and disease duration, as well as differential dynamic ultrasound changes under the two treatments and their links to pain relief.

Participants complete baseline assessments: demographic data, medical history, pain, anxiety, depression and quality-of-life scales, trigger point mapping, and bilateral orbicularis oris ultrasound (grayscale imaging, shear wave elastography, superb microvascular imaging). Subjects are randomly assigned 1:1 to bloodletting intervention or carbamazepine control for 8 weeks. The bloodletting group receives twice-weekly sterile trigger point pricking with cupping bleeding at suitable sites. The control group takes guideline-based individualized carbamazepine, with all subjects maintaining daily pain and medication diaries.

Follow-up evaluations occur at Weeks 2, 4, 6 and 8, covering pain scoring, trigger point re-evaluation and adverse event monitoring. Post-treatment bilateral orbicularis oris ultrasound is performed at Week 8 to quantify changes in soft tissue structure and microcirculation. All adverse reactions and concurrent medications are documented throughout the trial. Baseline observational analysis compares pretreatment bilateral facial muscle ultrasound features and correlates imaging indicators with clinical pain, to provide objective imaging evidence for peripheral sensitization pathology of trigger points in trigeminal neuralgia patients.

Study Overview

• Status: Not yet recruiting
• Conditions: Trigeminal Neuralgia (TN)
• Intervention / Treatment: Procedure: Trigger Point Bloodletting Therapy; Drug: Carbamazepine

Detailed Description

The goal of this randomized controlled clinical trial with embedded observational baseline analysis is to evaluate the clinical efficacy of trigger point bloodletting therapy for primary trigeminal neuralgia and explore peripheral musculoskeletal ultrasound mechanisms of trigger point lesions and treatment response. This study enrolls adult participants aged 18 to 75 years with unilateral classic or idiopathic primary trigeminal neuralgia and definite trigger points located in the upper lip orbicularis oris muscle.

The main questions it aims to answer are:

Does eight weeks of trigger point bloodletting therapy deliver a larger decline in Brief Pain Inventory Facial total score which serves as the primary efficacy endpoint compared with routine oral carbamazepine treatment among participants with primary trigeminal neuralgia? Do orbicularis oris muscle ultrasonographic indicators including soft tissue thickness elasticity and microvascular blood flow present discrepancies between affected sides and contralateral unaffected sides, and do these imaging indicators correlate with pain severity and disease course length? Do the two intervention regimens lead to distinct dynamic variations in orbicularis oris muscle ultrasound parameters, and do such structural and microcirculation variations correlate with clinical pain relief degrees? Researchers will compare participants receiving trigger point bloodletting intervention and participants receiving carbamazepine control treatment to identify whether trigger point bloodletting therapy yields better pain relief and more obvious recovery of soft tissue structure and microcirculation in trigger point regions.

Participants will finish all scheduled study procedures within an eight week treatment cycle as follows Complete baseline screening and systematic assessments covering demographic information medical history collection clinical pain evaluation and quality of life scale measurement. Scales adopted include Brief Pain Inventory Facial visual analogue scale self rating depression scale self rating anxiety scale and the 36 Item Short Form Health Survey. Researchers conduct full range trigger point localization feature recording and bilateral orbicularis oris muscle ultrasound detection. Ultrasound detection includes grayscale imaging shear wave elastography and superb microvascular imaging modules.

Receive random grouping allocation at a one to one ratio to either trigger point bloodletting group or carbamazepine control group.

Accept corresponding standardized intervention for eight consecutive weeks. Participants in bloodletting group receive trigger point bloodletting therapy two times each week with no less than two days interval between adjacent treatment sessions. Operators implement sterile pricking on confirmed trigger points and conduct cupping auxiliary bleeding for anatomical positions suitable for cupping operation to reach standardized therapeutic blood volume.

Participants in control group take oral carbamazepine tablets following official clinical guidelines with individualized dose adjustment range. All participants record daily medication dosage and real time pain conditions in designated pain diaries.

Attend follow up assessment visits at week two week four week six and week eight. Each follow up includes pain scale scoring repeated trigger point feature evaluation and whole process adverse event surveillance.

Undergo post treatment orbicularis oris muscle ultrasound re examination at week eight to quantify longitudinal changes of soft tissue thickness tissue elasticity and microvascular blood flow signals.

Record all adverse reactions concomitant drugs and unexpected adverse events throughout the entire research period.

The observational baseline analysis takes all pre treatment ultrasound data to compare imaging differences between bilateral facial muscles and analyze correlation relationships between ultrasonic indicators and clinical pain indexes. This part of analysis intends to provide imaging based objective evidence supporting peripheral sensitization pathological changes of trigger points in primary trigeminal neuralgia patients.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Huilin Liu, Dr; Phone Number: 8618827062868; Email: 306916598@qq.com

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 250012
      • Capital Medical University Affiliated Beijing Hospital of Traditional Chinese Medicine
      • Contact: Xiaoyan Li; Phone Number: 08613789817819; Email: llxiaoyan@126.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Participants aged 18 to 75 years old
• Participants diagnosed with primary trigeminal neuralgia
• Participants with definite facial trigger points located in the orbicularis oris muscle of upper lip
• Participants whose pain meets the diagnostic criteria of classic or idiopathic primary trigeminal neuralgia
• Participants with visual analogue scale pain score no less than 4 at screening
• Participants who can understand scale evaluation and complete follow-up visits on schedule
• Participants sign written informed consent voluntarily

Exclusion Criteria:

• Secondary trigeminal neuralgia caused by tumor vascular compression inflammation or other organic lesions
• History of facial surgery radiofrequency ablation or nerve block treatment within three months
• Receiving acupuncture bloodletting or similar physical therapy on facial region within one month
• Severe uncontrolled systemic diseases including heart liver kidney and hematological disorders
• Coexisting mental disorders that affect pain assessment and follow up Pregnant or lactating women
• Known allergy to carbamazepine or bloodletting operation contraindications such as coagulation dysfunction
• Participants who are unable to cooperate with ultrasound examination

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Trigger Point Bloodletting Therapy Group; Participants receive standardized trigger point bloodletting therapy for 8 consecutive weeks.	Procedure: Trigger Point Bloodletting Therapy; Sterile disposable bloodletting needles are used for pricking at confirmed facial trigger points of patients with primary trigeminal neuralgia. Cupping-assisted bleeding is conducted at anatomically appropriate regions. The treatment is delivered twice weekly for 8 consecutive weeks, with an interval of no less than two days between two adjacent treatment sessions.; Other Names: Trigger Point Pricking; Cupping Bloodletting
Active Comparator: Oral Carbamazepine Control Group; Participants receive individualized oral carbamazepine treatment for 8 consecutive weeks.	Drug: Carbamazepine; Participants receive oral carbamazepine tablets. The dosage is adjusted individually according to clinical guidelines to control pain symptoms, and the maximum daily dose does not exceed 1.2 g. The treatment lasts continuously for 8 weeks.; Other Names: Carbamazepine Oral Administration

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Brief Pain Inventory-Facial total score	Full unabbreviated scale title: Brief Pain Inventory-Facial. Total score minimum value = 0, maximum value = 100. This item measures the change in total score from baseline to the 8-week endpoint. Higher scores indicate more severe facial pain (worse outcome), lower scores indicate milder facial pain.	Baseline to 8 weeks after intervention initiation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Visual Analogue Scale pain score	Full unabbreviated scale title: Visual Analogue Scale. Score minimum value = 0, maximum value = 10. This outcome assesses the change in pain score from baseline to the 8-week endpoint. Higher scores indicate stronger pain sensation (worse outcome), lower scores indicate slighter pain.	Baseline to 2 weeks, 4 weeks, 6 weeks, 8 weeks
Change in orbicularis oris muscle soft tissue thickness	This outcome evaluates the change in soft tissue thickness of orbicularis oris muscle measured via grayscale ultrasound from baseline to the 8-week endpoint, measured in millimeters (mm). Lower or higher thickness values reflect altered local soft tissue structure at trigger points.	Baseline to 8 weeks
Change in orbicularis oris muscle shear wave elasticity	This outcome evaluates the change in shear wave elasticity of orbicularis oris muscle measured via shear wave elastography ultrasound from baseline to the 8-week endpoint, measured in kilopascals (kPa). Higher elasticity values indicate stiffer soft tissue at trigger points.	Baseline to 8 weeks
Change in orbicularis oris muscle microvascular blood flow signal	This outcome evaluates the change in microvascular blood flow signal of orbicularis oris muscle measured via superb microvascular imaging from baseline to the 8-week endpoint, quantified by semi-quantitative blood flow grading. Higher grading scores represent richer local microvascular perfusion.	Baseline to 8 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of adverse events	The number and incidence of adverse events occurring throughout the 8-week treatment period.	Within 8 weeks after intervention start

Collaborators and Investigators

• Sponsor: Beijing Hospital of Traditional Chinese Medicine

Study record dates

Study Major Dates

• Study Start (Estimated): August 31, 2026
• Primary Completion (Estimated): July 31, 2027
• Study Completion (Estimated): August 31, 2027

Study Registration Dates

• First Submitted: July 31, 2026
• First Submitted That Met QC Criteria: August 5, 2026
• First Posted (Actual): August 6, 2026

Study Record Updates

• Last Update Posted (Actual): August 6, 2026
• Last Update Submitted That Met QC Criteria: August 5, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mouth Diseases; Stomatognathic Diseases; Nervous System Diseases; Cranial Nerve Diseases; Trigeminal Nerve Diseases; Facial Neuralgia; Facial Nerve Diseases; Trigeminal Neuralgia; Heterocyclic Compounds; Heterocyclic Compounds, Fused-Ring; Dibenzazepines; Heterocyclic Compounds, 3-Ring; Carbamazepine
• Other Study ID Numbers: 2024BL02-027-02; ZLRK202324 (Other Grant/Funding Number: Beijing Municipal Administration of Hospitals)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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