Ultrasound-Guided Intervention for Treatment of Trigeminal Neuralgia: An Updated Review of Anatomy and Techniques

Abstract

Orofacial myofascial pain is prevalent and most often results from entrapment of branches of the trigeminal nerves. It is challenging to inject branches of the trigeminal nerve, a large portion of which are shielded by the facial bones. Bony landmarks of the cranium serve as important guides for palpation-guided injections and can be delineated using ultrasound. Ultrasound also provides real-time images of the adjacent muscles and accompanying arteries and can be used to guide the needle to the target region. Most importantly, ultrasound guidance significantly reduces the risk of collateral injury to vital neurovascular structures. In this review, we aimed to summarize the regional anatomy and ultrasound-guided injection techniques for the trigeminal nerve and its branches, including the supraorbital, infraorbital, mental, auriculotemporal, maxillary, and mandibular nerves.

Figure 1

Anatomy of the supraorbital notch, infraorbital foramen, and mental foramen with corresponding neurovascular structures and the course of the auriculotemporal nerve: (a) 1 = supraorbital notch containing the supraorbital nerve and vessels; 2 = infraorbital foramen containing the infraorbital nerve and vessels; 3 = mental foramen containing the mental nerve and vessels; 4 = corrugator supercilii muscle, which is superficial to the supraorbital notch; 5 = levator labii superioris muscle, which is superficial to the infraorbital foramen; 6 = depressor labii inferioris muscle, which is superficial to the mental foramen, and (b) 7 = auriculotemporal nerve; 8 = temporalis muscle; P = parotid gland.

Figure 2

Topography of the sensory distribution of the (a) supraorbital nerve, (b) infraorbital nerve, (c) mental nerve, (d) auriculotemporal nerve, and (e) deep branches of the trigeminal nerve; 1 = area supplied by the maxillary nerve and 2 = area supplied by the mandibular nerve.

Figure 3

Sonoanatomy and ultrasound-guided injection technique for the supraorbital nerve: (a) the position of the transducer (yellow rectangle), (b) ultrasound imaging of the supraorbital nerve emerging from the supraorbital notch, (c) introducing the needle in the lateral-to-medial direction using the in-plane approach to target the supraorbital nerve, and (d) power Doppler image of the supraorbital vessels. The asterisk (∗) denotes the supraorbital notch on the face. The empty white arrows denote the supraorbital margin. The solid white arrow denotes the supraorbital nerve. The yellow dashed arrow denotes the needle trajectory. CSM: corrugator supercilii muscle and M: medial side. All the pictures were obtained from the face of the first author.

Figure 4

Sonoanatomy and ultrasound-guided injection technique for the infraorbital nerve: (a) the transducer position (yellow rectangle), (b) ultrasound image of the infraorbital nerve (white solid arrow) from the infraorbital foramen, (c) introducing the needle in the lateral-to-medial direction using the in-plane approach to target the infraorbital nerve, and (d) power Doppler image of the infraorbital vessels. The asterisk (∗) denotes the infraorbital foramen on the face. The empty white arrows denote the bony cortex of the maxilla. The yellow dashed arrow denotes the needle trajectory. LLSM: levator labii superioris muscle; ZM: zygomaticus minor muscle; MF: malar fat; M: medial side. All the pictures were obtained from the face of the first author.

Figure 5

Sonoanatomy and ultrasound-guided injection technique for the mental nerve: (a) the transducer position (yellow rectangle), (b) ultrasound imaging of the mental nerve (white solid arrow), (c) introducing the needle from the lateral side toward the midline using the in-plane approach to target the mental nerve, and (d) power Doppler image used to identify the mental vessels. The empty white arrows denote the body of the mandible. The asterisk (∗) denotes the mental foramen on the face. The yellow dashed arrow denotes the needle trajectory. DLIM: depressor labii inferioris muscle; DAOM: depressor anguli oris muscle; JF: jowl fat; M: medial side. All the pictures were obtained from the face of the first author.

Figure 6

Sonoanatomy and ultrasound-guided injection technique for the auriculotemporal nerve: (a) the transducer position (yellow rectangle), (b) ultrasound imaging of the auriculotemporal nerve (white solid arrow), (c) introducing the needle in the posterior-to-anterior direction using the in-plane approach to target the auriculotemporal nerve, and (d) the power Doppler image of the superficial temporal artery. The empty white arrows denote the zygomatic arch. The yellow dashed arrow indicates the needle trajectory. MCFC: middle cheek fat compartment and LTCF: lateral temporal cheek fat. All the pictures were obtained from the face of the first author.

Figure 7

Anatomy of the maxillary and mandibular nerves related to the lateral pterygoid plate.

Figure 8

Ultrasound-guided injection technique for the maxillary and mandibular nerves: (a) the transducer position and required placement for the maxillary nerve, (b) the transducer position and required placement for the mandibular nerve, and (c) color Doppler image during mouth opening. The yellow dashed arrow represents the needle trajectory for injection of the maxillary nerve, while the red dashed arrow represents the needle trajectory for injection of the mandibular nerve. The empty white circle denotes the pterygopalatine fossa. COP: condylar process; DM: deep masseter; LPM: lateral pterygoid muscle; LPP: lateral pterygoid plate; TM: temporalis muscle; SM: superficial masseter; SA: sphenopalatine artery. All the pictures were obtained from the face of the first author.