Ultrasound-Guided Botulinum Toxin A Injection for TMJ Disc Displacement With Reduction

Evaluation of the Ultrasonography-Guidance for Botulinum Toxin Type A Injection Into Lateral Pterygoid Muscle in Patients With TMJ Anterior Disc Displacement With Reduction

This clinical trial was designed to evaluate the effectiveness of ultrasonography-guided botulinum toxin type A (BTX-A) injection into the lateral pterygoid muscle for the management of temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDwR). Ten patients diagnosed with ADDwR participated in the study. Each patient received an ultrasound-guided injection of 25 units of BTX-A into the lateral pterygoid muscle under local anesthesia. Clinical evaluations were performed preoperatively and at 2, 6, 12, and 24 weeks postoperatively. Outcome measures included pain levels assessed by the Numerical Rating Scale (NRS), TMJ sounds (clicking) detected using a stethoscope, disc position assessed by MRI, mandibular function parameters such as lateral excursion and maximum interincisal opening, and the Fonseca's questionnaire scores. The results demonstrated a significant reduction in pain and TMJ sounds, improvement in disc position, and enhanced mandibular function over a 6-month follow-up period. These findings suggest that ultrasonography-guided BTX-A injection into the lateral pterygoid muscle is a safe and effective treatment option for patients with TMJ ADDwR.

This study investigated the therapeutic potential of ultrasonography-guided botulinum toxin type A (BTX-A) injection into the lateral pterygoid muscle in patients diagnosed with temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDwR). The intervention was performed under local anesthesia with patient monitoring. High-frequency ultrasonography was utilized to accurately identify the lateral pterygoid muscle and guide the injection to minimize risks to adjacent anatomical structures.

The study followed patients over a 6-month period to assess changes in TMJ-related pain, functional parameters, and disc position. Pain intensity was measured using the Numerical Pain Rating Scale (NPRS), joint sounds were assessed clinically and with a stethoscope, disc position was evaluated via MRI, and mandibular movements were assessed by measuring lateral excursion and maximum interincisal opening. Patient-reported outcomes were also evaluated using the Fonseca's questionnaire.

The findings demonstrated a significant reduction in TMJ pain and joint noises, as well as improved mandibular function and disc alignment during the follow-up period. No major complications were observed, supporting the safety and efficacy of ultrasound-guided BTX-A injections in managing ADDwR.

This research provides clinical evidence for a minimally invasive and precise technique to manage TMJ internal derangements and reduce the impact of hyperactive lateral pterygoid muscle activity.

Inclusion Criteria:

• Patients diagnosed with bilateral anterior disc displacement with reduction (ADDwR) using Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD).
• Patients aged 18 years or older.
• Patients who did not respond to previous conservative treatments.

Exclusion Criteria:

• Known allergy to any components of botulinum toxin type A (BTX-A).
• Presence of temporomandibular joint (TMJ) hypermobility.
• History of TMJ surgery.
• Presence of any significant pathology around the TMJ.
• Pregnant women.
• Individuals with systemic diseases that may affect the TMJ or the procedure.
• Patients with blood coagulopathy.
• Patients with unilateral ADDwR.