Effects of Remifentanil on Cardiovascular Stimulation Caused by Local Anesthetic With Epinephrine: A Power Spectral Analysis.

The objectives of this research were to investigate (a) what was the most effective infusion rate of remifentanil and (b) the degree to which sympathomimetic effects were involved with cardiovascular stimulation by using a power spectral analysis of heart rate variability (HRV). A total of 63 healthy individuals scheduled for sagittal split ramus osteotomy were enrolled and randomly allocated to 1 of 3 groups: remifentanil infusion rate of 0.1, 0.2, or 0.4 µg/kg/min. Anesthesia was maintained with remifentanil and propofol. Before the surgical procedure, 2% lidocaine containing 12.5 µg/mL epinephrine was administered in the surgical field for local anesthesia. Systolic blood pressure (SBP), heart rate (HR), low-frequency (LF) and high-frequency (HF) components in HRV power spectral analysis, and the LF/HF ratio were analyzed. Increases in SBP and HR were observed after local anesthesia in all 3 groups, but no significant differences were observed between the groups. Remifentanil infusion at 0.1 µg/kg/min may be appropriate to minimize cardiovascular stimulation caused by exogenous epinephrine from local anesthesia. Although a rise in the LF/HF ratio was observed after local anesthesia in all groups, no relationship was observed between the cardiovascular changes and the increase in LF/HF ratio. This suggests that sympathomimetic effects are involved to a lesser extent with the cardiovascular stimulation caused by exogenous epinephrine.

Acupuncture Combined with Trigger Point Injection in Patient with Chronic Myofascial and Referred Pain.

Here, we report a case in which acupuncture combined with trigger point injection was effective in a patient with chronic myofascial pain with referred pain in the masticatory muscles. The patient was a 46-year-old woman with the chief complaint of chronic persistent pain in the region of the left mandibular first molar, which had been extracted 5 months earlier. Stellate ganglion block was performed and amitriptyline administered at another hospital, but were ineffective. At her initial visit to our hospital, her primary complaint was chronic persistent pain in the region of the bilateral mandibular first molars. Several tender points were found on the masseter, temporalis, and sternocleidomastoid muscles, with bilateral referred pain. The pain score according to the visual analogue scale was 85. No significant psychological factors were found, however. Based on these findings, the diagnosis was chronic myofascial pain with referred pain in the masticatory muscles. Therefore, stretching of masticatory muscle and trigger point injection were performed. Two months later, the patient requested trigger point injections to be performed at all tender points, as the previous injections had been effective. The total volume of local anesthetic that this would require was considered to be excessive as there was a large number of tender points, however, and it was feared that a toxic reaction might occur. Therefore, acupuncture in combination with trigger point injection was selected instead. The symptoms disappeared within 9 months after commencement of this therapy, and treatment was completed within 1 year. The present results suggest that acupuncture therapy is effective when used in combination with trigger point injection.

Effect of Topical Anesthesia Using an Adhesive Patch and Anesthetic Solution.

We analyzed trigeminal somatosensory evoked potentials (TSEP) to the alveolar mucosa to investigate the efficacy of an amide local anesthetic, 2% lidocaine hydrochloride with 12.5 µg/mL epinephrine (Lido treatment) as a topical anesthetic. Eighteen consenting healthy adult volunteers were enrolled. A volume of 0.06 mL of Lido, 0.06 g of 20% benzocaine, or 0.06 mL of physiological saline (control) was instilled onto a hemostatic adhesive patch, which was then applied to the alveolar mucosa at the maxillary right canine for 5 minutes. An electrical stimulus approximately 5 times that of the sensory threshold was applied using a surface stimulation electrode. The trigeminal somatosensory evoked potential was recorded immediately, 5 minutes, and 10 minutes after removal of the patch. Positive P125 and P310 peaks and negative N100 and N340 peaks were observed as a result of the electrical stimulation. A significant decrease in the percentage change in amplitude of N100-P125 was observed in the Lido treatment immediately, 5 minutes, and 10 minutes after patch removal. In the Lido treatment, trigeminal somatosensory evoked potential amplitude at N100-P125 decreased significantly, suggesting that topical anesthesia produced by an amide local anesthetic may have a topical anesthetic effect as potent as that produced by an ester local anesthetic.

Effect of combination of trigger point injection and stellate ganglion block on non-odontogenic mandibular molar pain referred from masseter muscle: a case report.

We report a case of myofascial pain syndrome (MPS), manifested as nonodontogenic mandibular molar pain referred from the masseter muscle, relieved by a combination of trigger point injection (TPI) and stellate ganglion block (SGB). The patient was a 32-year-old woman who had experienced cold hypersensitivity in the right third mandibular molar 2 months prior to visiting our department. Subsequently, she had visited a family dentist and undergone pulpectomy under local anesthesia. She eventually visited our clinic because there was no marked change in her symptoms. On the first visit, no tooth abnormality was found and the patient was neither anxious nor depressive. Tender points were found in the right masseter and temporal muscles during muscle palpation. Referred pain radiating to the right mandibular molars was observed when pressure was applied to the central portion of the right masseter muscle. As a result, we diagnosed MPS based on evidence of nonodontogenic tooth pain caused by referred pain from the masseter muscle. We performed TPI with 2% lidocaine hydrochloride to the tender point in the masseter muscle. Although the visual analog scale (VAS) pain score dropped from 97 to 36, complete pain relief was not achieved. The TPI was effective for approximately 7 hrs, after which severe throbbing pain returned. The sustained nature of the tooth pain suggested that it was sympathetic nerve-dependent. Subsequently, we performed SGB, resulting in a reduction in the VAS pain score from 90 to 32. Therefore, we performed another TPI and the VAS pain score dropped to 0. We continued SGB and TPI for the next 3 days and the symptoms disappeared. Thus, a combination of TPI and SGB controlled MPS manifested as masseter muscle-mediated nonodontogenic tooth pain.

A new method of topical anesthesia by using anesthetic solution in a patch.

INTRODUCTION: We investigated the effects of topical anesthesia of the oral mucosa by using an adhesive patch instilled with 2% lidocaine hydrochloride solution. METHODS: The subjects were 20 healthy adult volunteers who gave written informed consent. Each patient was treated in a randomized crossover fashion with a hemostatic adhesive patch instilled with one of the following agents: 2% lidocaine hydrochloride with 12.5 µg/mL epinephrine, 2% lidocaine hydrochloride, 20% ethyl aminobenzoate, or physiological saline solution. A cotton ball containing 20% ethyl aminobenzoate was also tested. The adhesive patch or cotton ball was placed on the gingivobuccal fold of the maxillary right canine for 2 or 5 minutes. Then, a 33-gauge or 30-gauge needle was inserted to a depth of 2 mm. Insertion pain was evaluated with a visual analog scale (VAS) and a 4-level verbal rating scale immediately after needle removal. Efficacy of analgesia was calculated from the verbal rating scale. RESULTS: The VAS was lower and the efficacy of analgesia was higher on 33-gauge needle insertion than on 30-gauge needle insertion in all treatments. The VAS was also significantly lower and the efficacy of analgesia was higher in the lidocaine groups than in the other groups. Adding epinephrine did not enhance the anesthetic effect of lidocaine hydrochloride. CONCLUSIONS: Topical mucosal anesthesia with an adhesive patch containing 2% lidocaine hydrochloride solution is simple and may be more effective than conventional methods.

Lack of pain reduction by a vibrating local anesthetic attachment: a pilot study.

A vibrating dental local anesthesia attachment (Vibraject, LLC, Calif) based on the concept of the gate-control theory has been used in clinical practice. The theoretical advantage of the vibrating needle is that it reduces the injection pain. We evaluated the effectiveness of Vibraject in combination with an electrical injection device. Injections were given into the alveolar mucosa adjacent to the root apex of the maxillary lateral incisor in 10 volunteers. Vibraject was randomly applied to either the left or right side of the injection. No statistically significant decrease in pain scores was found at needle insertion or anesthetic injection. The clinical efficacy of Vibraject remains controversial.

Anxiety may enhance pain during dental treatment.

The purpose of this study was to clarify the effects of anxiety about dental treatment on pain during treatment. Subjects consisted of 57 consenting sixth-grade students at Tokyo Dental College (male: 32, female: 25), all of whom participated in this study during their clinical training program. They knew how third molars were extracted and all had experience of assisting in tooth extraction. Prior to the study, trait anxiety in the subjects was evaluated according to the State-Trait Anxiety Inventory (STAI, Japanese version). The students were asked to read one of two scenarios describing a scene in which a third molar was extracted while imagining themselves to be the patient. Scene 1 is set in an "environment where the patient feels safe and comfortable," and the Scene 2 is set in an "environment where the patient feels strong anxiety". The subjects were asked to imagine the anxiety and pain in that scenario and evaluate that pain according to a visual analogue scale (VAS). Two scenarios were randomly shown to the subjects in a crossover manner. No significant correlation between trait anxiety and preoperative anxiety was observed. There was no difference in level of preoperative anxiety for Scene 1 and Scene 2 between the high- and low-trait anxiety groups. This suggests that there was no relationship between sensitivity to anxiety as a characteristic of the subject and amplitude of anxiety immediately prior to treatment. Scene 2 elicited significantly higher anxiety before injection of regional anesthesia, significantly higher pain during insertion of the needle, and significantly higher pain during extraction of the tooth than Scene 1. This difference suggests that patients feel stronger pain if anxiety in the treatment environment is high and that it is, therefore, important to reduce anxiety during treatment to reduce pain.