Ultrasound-guided dry needling of masticatory muscles in trigeminal neuralgia - A case series of 35 patients

Abstract

Background: Trigeminal neuralgia (TGN) is considered a sensory neuropathy. However, reports of pain on chewing/speaking suggest a masticatory myofascial involvement.

Objective: To examine the effect of ultrasound-guided dry needling (USGDN), which deactivates myofascial trigger points in masticatory, neck, and facial muscles on TGN symptoms.

Methods: Charts of 35 patients treated for TGN were retrospectively reviewed. Treatment was USGDN alone or combined with trigeminal ganglion/mandibular nerve pulsed radiofrequency (PRF), followed by yoga mudras to stretch masticatory and facial muscles. Patients were followed for 1-8 years. Outcome parameters were reduction of medications with reduction in neuralgic attack frequency and Numeric Rating Scale (NRS) score.

Results: 23 patients (65.7%) received USGDN alone, 12 patients (34.3%) received PRF treatment before USGDN. A significant reduction in the mean (SD) NRS (5.7 [1.2] vs 8.8 [1.6]; P < .001) and neuralgic attack frequency (47 [27] vs 118 [70] attacks/day; P < .001) was seen after PRF compared with baseline, respectively. Following USGDN, the mean (SD) NRS further decreased significantly to 1.0 (0.9) (P < .001). USGDN alone produced a similar improvement in the NRS (8.9 [1.5] at baseline reduced to 0.6 [0.7] post-USGDN; P < .001). Patients in both groups reported a cessation in neuralgic attacks after USGDN. Post-USGDN, 18/27 patients completely discontinued medication, with the mean (SD) carbamazepine dose significantly reducing from 716.7 (260.9) mg/day at baseline to 113.0 (250.2) mg/day post-USGDN (P < .001).

Conclusion: Decisive relief of TGN by USGDN suggests neuromyalgia involving masticatory muscles. Prospective, controlled studies could confirm these findings.

Keywords: Neuromyalgia; neuromyopathy; pulsed radiofrequency; trigeminal neuralgia; ultrasound-guided dry needling.

Figure 1

Mandibular nerve supply to the muscles targeted by USGDN. The main trunk supplies medial pterygoid and meninges before division. Anterior division innervates the temporalis, lateral pterygoid, masseter, and buccal nerve (sensory). The posterior division supplies mylohyoid, anterior digastric belly (posterior belly by facial nerve), auriculotemporal, inferior alveolar, and lingual nerves (sensory). (Image courtesy of Dr Rakhi More)

Figure 2

Surface markings of muscles for needling. Dots indicating needle entry points into probable myofascial trigger points in muscles of face (supplied by facial nerves), neck (spinal accessory, cervical 1–3 nerves), and masticatory muscles (motor root of trigeminal via mandibular nerve) targeted by ultrasound-guided dry needling

Figure 3

Placement of the ultrasound probe (left) for showing needle placement (arrows) in the muscles during dry needling (right). First row: probe position for needling lateral pterygoids (LP). From cheek towards tragus. AAM - anterior aspect of mastoid. Second row: probe over the mandible (M) for needling superficial (SM) and deep masseters (DM). Third row: probe over the sternocleidomastoid (SCM). Fourth row: probe position for needling temporalis (T). N, needle; CA carotid; ant SC, anterior scalene

Figure 4

Poses of yoga mudras. Top row: Left: jihva bandha (tongue tie); center: simha mudra (lion pose); right: smaran vardhak pranayama (SVP) (inhalation). Middle row: Left and center: SVP (exhalation); right: khechari mudra. Bottom row: Left: sideway jaw movement; center and right: puffed-out cheeks and upper and lower lips

Figure 5

Dry needling and relief of trismus in a patient. Left: mouth opening prior to needling. Center: placement of needles in masticatory and neck muscles. Right: Mouth opening increased from 2 cm at the baseline (left) to 5 cm (right) after one session of needling

Figure 6

Pain referral from head, face, and neck muscles. Row 1: Left: V1, V2, and V3. Right: Frontalis, trapezius, splenius cervicis, temporalis, trapezius masseter, and sternomastoid refer pain to V1. Row 2: Left: Masseter, temporalis, pterygoids, orbicularis oculi, zygomaticus, and sternomastoid refer pain to V2. Right: Sternomastoid, masseter, temporalis, pterygoids, trapezius, digastric, and platysma refer pain to V3. (Image courtesy Dr Mary Abraham MD based on reference 10)