Hideki Furuya

Effectiveness of cervical sympathetic ganglia block on regeneration of the trigeminal nerve following transection in rats

Background and Objectives Stellate ganglion block (SGB) is one treatment option for human trigeminal nerve injury. The aim of this study was to evaluate the effectiveness of cervical sympathetic ganglia blocks (SB) by comparing the recovery of severed nerves in 2 rat models, treated or not treated by SB. Methods The infraorbital nerves (ION) were cut in 108 rats. Fifty-four of them were treated daily by SB for 30 days (SB group). The remainder were left untreated (Control group). The stages of recovery were evaluated neurophysiologically by measuring somatosensory evoked potentials (SEPs) and were histologically analyzed via microscopic observation. Results The neurophysiologic evaluation showed that SEP amplitude was detected 1 month after cutting the ION in the SB group, but not in the Control group. The average recovery after 8 months was almost 100% in the SB group and about 70% in the Control group. The histologic evaluation showed no significant difference in the number of myelinated nerve fibers per unit area between the 2 groups. However, in the SB group, the mean diameter and distribution of diameters of the myelinated fibers were greater, and myelinated fibers of large diameter were observed at an early stage. Conclusions The findings suggest that cervical sympathetic nerve block may accelerate the recovery and regeneration of severed ION. The clinical correlation in patients with peripheral trigeminal paralysis remains to be established.

Anesthetic Management of a Patient With Sturge-Weber Syndrome Undergoing Oral Surgery

This case involves a possible complication of excessive bleeding or rupture of hemangiomas. Problems and anesthetic management of the patient are discussed. A 35-year-old man with Sturge-Weber syndrome was to undergo teeth extraction and gingivectomy. Hemangiomas covered his face and the inside of the oral cavity. We used intravenous conscious sedation with propofol and N2O-O2 to reduce the patients emotional stress. It was previously determined that stress caused marked expansion of this patients hemangiomas. Periodontal ligament injection was chosen as the local anesthesia technique. Teeth were extracted without excessive bleeding or rupture of hemangiomas, but the planned gingivectomies were cancelled. Deep sedation requiring airway manipulation should be avoided because there are possible difficulties in airway maintenance. Because this was an outpatient procedure, propofol was selected as the sedative agent primarily because of its rapid onset and equally rapid recovery. Periodontal ligament injection with 2% lidocaine containing 1: 80,000 epinephrine was chosen for local anesthesia. Gingivectomy was cancelled because hemostasis was challenging. As part of preoperative preparation, equipment for prompt intubation was available in case of rupture of the hemangiomas. The typically seen elevation of blood pressure was suppressed under propofol sedation so that expansion of the hemangiomas and significant intraoperative bleeding was prevented. Periodontal ligament injection as a local anesthetic also prevented bleeding from the injection site.

Clonidine as a drug for intravenous conscious sedation

Abstract Clonidine, an α2-adrenoceptor agonist, was introduced to clinical practice in the 1960s because of its antihypertensive effect. It has several beneficial actions during the perioperative period, particularly for medically compromised patients. The objective of this study was to evaluate the effects of clonidine as a drug for intravenous conscious sedation. We assessed the effects of intravenous clonidine on the hemodynamic and sympathoadrenergic responses to nociceptive stimuli and we evaluated its sedative and analgesic effects. Twenty-five volunteers aged between 23 and 25 years were included in this study. They received clonidine intravenously at 2 μg/kg. Constant-current, square-wave stimuli were delivered as nociceptive stimuli to the median nerve of the arm. We measured blood pressure, heart rate, cardiac output, and plasma concentrations of noradrenaline, adrenaline, and cortisol. The sedative and analgesic effects were measured by visual analogue scales. Changes in heart rate and blood pressure were not significantly different between the clonidine and control groups. Cardiac output tended to decrease after clonidine administration. Clonidine exerted its greatest sedative effect 30 min after injection. Noradrenaline concentration reached its nadir 15 min after clonidine administration. The time course of adrenaline concentrations was similar to that of noradrenaline. The plasma concentration of cortisol decreased in both groups. The most common adverse effect was dry mouth. In conclusion, intravenous clonidine, at a dose of 2 μg/kg, did not induce significant bradycardia, hypotension, or severe side effects in the healthy volunteer. It attenuated the adrenergic response to electrical stimulation. The results suggested that clonidine is a useful drug for intravenous sedation.