A Novel Injection Technique to the Lateral Pterygoid Muscle for Temporomandibular Disorders: A Cadaveric Study

Abstract

Background: Lateral pterygoid muscle activity is associated with the pathological mechanisms of some temporomandibular disorders. The authors aimed to define and demonstrate a novel, practical, and safe technique for botulinum toxin type A injection to the lateral pterygoid muscle based on their findings. Their secondary aims were to standardize the injection pattern according to the variations of the lateral pterygoid muscle and its surrounding anatomical structures, and to establish its advantages over intraoral injection. Methods: Twenty cadaver heads were dissected. The lateral pterygoid muscle and its surrounding structures were investigated for anatomical variations. Based on these findings, a standardized extraoral injection protocol was defined and compared with the intraoral technique for accuracy and safety. Results: The average depth of the lateral pterygoid plate from the skin surface was 49.9 ± 2.2 mm, and the mean width of the lateral pterygoid plate was 10.5 ± 3.9 mm. The extraoral injection approach based on the location of the maxillary tuberosity, tragus, and lateral pterygoid plate was consistent in all dissections for the accuracy of the intramuscular injection. In the intraoral approach, standardization of the entry point of the needle through the oral mucosa is difficult, which makes adjustment of the depth of the injection challenging while increasing the risk of neurovascular injury. Conclusions:The clinical significance of the lateral pterygoid muscle makes it worthwhile to implement minimally invasive treatments before considering more invasive options. The authors define a safe, accurate, and reliable approach with ease of administration in patients with temporomandibular disorders.

Toxina botulínica na disfunção temporomandibular

“…A segurança e eficácia da toxina botulínica foram amplamente respaldadas por uma pesquisa científica conduzida por Kucukguven et al, (2021). O estudo, que envolveu a dissecação e padronização de 21 cabeças de cadáveres, desenvolveu uma técnica intraoral precisa considerando variações anatômicas individuais.…”

“…O estudo, que envolveu a dissecação e padronização de 21 cabeças de cadáveres, desenvolveu uma técnica intraoral precisa considerando variações anatômicas individuais. A aplicação da toxina botulínica tipo A no músculo pterigoideo lateral, por meio de abordagens intra e extraorais, resultou em resultados positivos, reforçando a consideração da toxina botulínica como uma abordagem benéfica, rápida e eficaz para o tratamento de pacientes com DTM (Kucukguven et al, 2021).…”

O uso da toxina botulínica tipo A como alternativa terapêutica na disfunção temporomandibular: uma revisão de literatura

“…A técnica de injeção padronizada, baseada na localização da tuberosidade maxilar, tragus e placa pterigóide lateral foi consistente em todas as dissecções para a precisão da injeção intramuscular. O resultado demonstrou que a técnica da toxina botulínica é um tratamento seguro e eficaz, concluindo que o uso da toxina botulínica pode ser uma abordagem segura e eficaz em pacientes com DTM, porém devem ser feitos novos estudos clínicos para avaliar a eficácia no tratamento da DTM (KUCUKGUVEN A, et al, 2021).…”

Preliminary Findings of the Efficacy of Botulinum Toxin in Temporomandibular Disorders: Uncontrolled Pilot Study

“…A 1 cc marked insulin syringe was used for intramuscular injection of the prepared solution, according to the locations and amounts proposed by Kim et al and Ho et al [ 21 , 22 ], with a total dose of 100 U in each patient, distributed at the different injection sites: 40 U in the masseter muscle, (0.1 cc = 10 U), 20 U in the area of greatest hypertrophy (anterior inferior masseter, point 1), 10 U in the direction of the mandibular inferior border (point 2, middle inferior masseter) and 10 U in the area of the posterior inferior masseter (point 3); 20 U in the lateral pterygoid muscle (10 U extraorally between the zygomatic arch and sigmoid notch and 10 U intraorally, behind the maxillary tuberosity) (points 4 and 5); 20 U in the TMJ (point 6), 10mm anterior to the tragus and 2mm below the zygomatic arch; and 20 U in the anterior part of the temporalis muscle (points 7 and 8). The location of the injection point in the lateral pterygoid muscle was performed taking as a reference, in front of the coronoid process, behind the mandibular condyle, above the zygomatic arch and below the mandibular sigmoid notch, penetrating this area with the needle in an anteroposterior and cranial direction, with an angle of 15° with respect to the anterior border of the mandibular condyle; the injection needle in our study reached a depth of 2.5 cm ± 0.5 cm [ 23 , 24 , 25 ].…”