Background
Trigeminal neuralgia is a neuropathic disorder characterized by episodes of intense
pain in the face.
Drug therapy is the first choice of treatment. However, in cases where
drug therapy are contraindicated due to side effects, patients can get
pain relief from lengthy
neurosurgical procedures. Alternatively, a peripheral trigeminal nerve block can be easily performed in an outpatient setting. Therefore it is a useful treatment option for the acute paroxysmal period of TN in patients who cannot use
drug therapy. We performed real-time ultrasound guidance for infraorbital
nerve blocks in TN patients using a high concentration of
tetracaine dissolved in
bupivacaine. In this report, we examine the efficacy of our methods. Patients As approved by the Institutional Review Board, the medical records in our hospital were queried retrospectively. Six patients with TN at the V2 area matched the study criteria. All patients could not continue
drug therapy with
carbamazepine due to side effects and they received an ultrasound-guided infraorbital
nerve block with a high concentration of
tetracaine dissolved in
bupivacaine. Methods The patient was placed in the supine position and the patient's face was sterilized and draped. An ultrasound system with a 6-13 MHz linear probe was used with a sterile cover. The probe was inserted into the horizontal plane of the cheek just beside the nose and was slid in the cranial direction to find the dimple of the infraorbital foramen. The 25G 25 mm needle was inserted from the caudal side just across from the probe using an out-of-plane approach. To lead the needle tip to the foramen, needle direction was corrected with real-time ultrasound guidance. After the test block with
lidocaine (2%, 0.5 ml), a
solution of
tetracaine (20 mg) dissolved in
bupivacaine (0.5%, 0.5 ml) was injected. During each injection, the spread of the agent around the nerve was confirmed using ultrasound images. Results Ten blocks were performed for six patients. Immediately after the procedure, all 10 blocks produced
analgesia and relieved the
pain. In the three blocks,
pain was experienced in a new trigger point outside of the infraorbital nerve region (around the back teeth) within a week after the block and
pain were relieved using other treatment. Two patients developed small
hematomas in the cheek but they disappeared in a week. All patients did not complain about other side effects including paraesthesia, hyperpathia, dysaesthesia, or
double vision. Hypoaesthesia to touch and
pain in the infraorbital region were observed in all blocks after 2 weeks. Conclusions We performed real-time ultrasound-guided infraorbital
nerve block for TN with a high concentration of
tetracaine dissolved in
bupivacaine. Our method achieved a high success rate and there were only minor and transient side effects. Implications Real-time ultrasound-guided infraorbital
nerve block is one of the useful options to treat the acute paroxysmal period of TN at the infraorbital nerve area. Ultrasound-guided
injections may become the standard practice for injecting peripheral trigeminal nerves. Using this high concentration of
tetracaine as a neurolytic agent is effective and appears to have only minor side effects.