Injectate spread in ultrasound-guided inferior alveolar nerve block: a cadaveric study.

PURPOSE: Ultrasound-guided inferior alveolar nerve block (UGIANB) is a mandibular analgesic procedure in which local anesthetic is injected into the pterygomandibular space (PMS). Several studies have reported the clinical efficacy of UGIANB for mandibular surgeries; however, its effective range has never been investigated. We performed a cadaveric study to investigate the success rate of UGIANB injections and to determine whether injected dye could stain the mandibular nerve (MN) trunk and its branches. METHODS: We performed UGIANB on the bilateral faces of 4 Thiel-embalmed cadavers. A needle was advanced to the PMS under ultrasound guidance and 5 mL of dye was injected. The cadaver was dissected and inspected for the presence of dye in the PMS; the range of dye spread to any of the inferior alveolar nerve (IAN), lingual nerve (LN), buccal nerve (BN), mandibular nerve (MN), auriculotemporal nerve (ATN), or facial nerves; and for the presence of intravascular dye. RESULTS: We performed eight UGIANB procedures on four cadavers. Dye was observed in the PMS in 7/8 injections. Staining was observed in all IAN, LN, and BNs that could be identified at dissection. No MN or auriculotemporal nerves (ATNs) were stained in any injections. No intravascular dye was observed in any injections. CONCLUSIONS: UGIANB can administer anesthetic into the PMS with high accuracy. UGIANB injections reached the IAN, LN, and BNs, but did not reach the MN or ATNs located outside the PMS. The findings of this cadaveric study indicate that UGIANB can provide sufficient analgesia for mandibular surgeries.

Ultrasound-Guided Selective Glossopharyngeal Nerve Block for Severe Gag Reflex During Dental Treatment: A Report of Two Cases.

The ultrasound-guided selective glossopharyngeal nerve block (UGSGNB) has been developed as an approach to overcome the drawbacks of the conventional glossopharyngeal nerve block. The UGSGNB may be performed when a gag reflex occurs during dental treatment. Case 1 involved a 67-year-old man with a medical history of cervical spondylosis and dilated cardiomyopathy. Dental treatment with conscious sedation and the UGSGNB was performed three times. Case 2 involved a 25-year-old woman who was scheduled for dental treatment under general anesthesia because of dental phobia and gagging. Because the patient experienced severe tooth pain and desired urgent treatment, anesthesia was induced with intravenous sedation and the UGSGNB. In both cases, treatments were completed without intraoperative gagging or any complications. Our observations indicate that the UGSGNB can suppress the gag reflex during dental treatment; it may allow surgeons to avoid inducing general anesthesia and deep sedation in patients with a severe gag reflex.

Mouth-Opener Technique for Ultrasound-Guided Inferior Alveolar Nerve Block: A Case Series of Extraction of Impacted Mandibular Third Molars.

Extraction of the impacted mandibular third molar (IMTM) is common in oral surgery, but its postoperative pain is severe. Ultrasound-guided inferior alveolar nerve block (UGIANB) is an analgesic technique in the mandibular nerve region. We describe UGIANB using a mouth opener and report the cases with a good postoperative course. Six patients underwent the extraction of bilateral IMTMs under general anesthesia. After surgery, we performed UGIANB and administered 5 mL of 0.375% levobupivacaine on each side. The postoperative numerical rating scale pain scores were 1 (0-2) and 2.5 (0-5) (mean (range)), postoperative day one and seven, respectively. The postoperative quality of recovery-40 scores were 188.5 (8.1) and 191.7 (7.6) (mean (SD)), postoperative day one and seven, respectively. No procedural complications were encountered. We performed UGIANB with a mouth opener on a patient with IMTM extraction and were able to provide safe and good analgesia.