Review of the Current Medical and Surgical Treatment Options for Microstomia in Patients With Scleroderma.

BACKGROUND: Most patients with scleroderma suffer from microstomia, which can have debilitating consequences on their quality of life. Unfortunately, treatment options remain limited. No specific guidelines exist; hence, microstomia remains a challenge to treat in this patient population. OBJECTIVE: This review aims to evaluate the different medical and surgical treatment modalities currently available for microstomia in patients with scleroderma and make recommendations for future research. MATERIALS AND METHODS: A search of PubMed, Ovid MEDLINE, and Ovid Embase was conducted to identify articles discussing the treatment of microstomia in scleroderma. Twenty articles discussing surgical therapy and one article discussing medical therapy were reviewed. RESULTS: Mostly because of a scarcity of high-level evidence, no individual therapy has documented long-term efficacy. Some treatments demonstrate positive results and warrant further research. CONCLUSION: Given the variability of results, specific recommendations for the treatment of microstomia in patients with scleroderma are difficult to establish. A multifaceted approach that includes surgical and medical therapy is likely the best option to improve oral aperture in this patient population. Surgical treatments such as neurotoxins, autologous fat grafting, and ultraviolet A1 phototherapy may hold the most potential for improvement.

Muscle-Nerve-Muscle Grafting for Facial Reanimation in Rats.

OBJECTIVE: Facial paralysis is a devastating condition leaving patients with a myriad of aesthetic and functional consequences. Muscle-nerve-muscle (MNM) neurotization is a reinnervation technique that involves implanting an autogenous nerve graft as a conduit between an innervated "donor" muscle and a denervated "recipient" muscle. We investigated the use of MNM reinnervation, alone or in combination with electrical stimulation (ES) and testosterone propionate (TP) in comparison to nerve reanastomosis (RE), on functional recovery following rat facial nerve injury. METHODS: Thirty-one male, Sprague-Dawley rats were assigned to groups: no graft (control), MNM grafting alone (MNM), MNM grafting with ES and TP (MNM+ES+TP), or RE. Harvested right facial nerve branches were used as the MNM graft. Functional recovery was assessed by behavioral observations and electromyographic recordings. RESULTS: The MNM grafting improved muscle tone and vibrissae movement. The ES+TP treatment further enhanced muscle tone as well as reduced recovery time for coordinated movement in a manner that is comparable to those of RE. Electromyographic recordings demonstrated electrical conductance across all MNM grafts. CONCLUSION: These data have important implications for patients with unilateral paralysis from facial or laryngeal nerve injury, particularly those who are not candidates for nerve reanastomosis.

Topographic Relationship between the Supratrochlear Nerve and Corrugator Supercilii Muscle--Can This Anatomical Knowledge Improve the Response to Botulinum Toxin Injections in Chronic Migraine?

Chronic migraine has been related to the entrapment of the supratrochlear nerve within the corrugator supercilii muscle. Recently, research has shown that people who have undergone botulinum neurotoxin A injection in frontal regions reported disappearance or alleviation of their migraines. There have been numerous anatomical studies conducted on Caucasians revealing possible anatomical problems leading to migraine; on the other hand, relatively few anatomical studies have been conducted on Asians. Thus, the aim of the present study was to determine the topographic relationship between the supratrochlear nerve and corrugator supercilii muscle in the forehead that may be the cause of migraine. Fifty-eight hemifaces from Korean and Thai cadavers were used for this study. The supratrochlear nerve entered the corrugator supercilii muscle in every case. Type I, in which the supratrochlear nerve emerged separately from the supraorbital nerve at the medial one-third portion of the orbit, was observed in 69% (40/58) of cases. Type II, in which the supratrochlear nerve emerged from the orbit at the same location as the supraorbital nerve, was observed in 31% (18/58) of cases.

Ten Mistakes To Avoid When Injecting Botulinum Toxin.

Injection of botulinum toxin is currently the most common cosmetic procedure in the United States, and in recent years it has become-together with dermal fillers-the mainstay of therapy for the prevention and treatment of facial aging. However, in some cases the treatment may lead to a somewhat unnatural appearance, usually caused by loss of facial expression or other telltale signs. In the present article, we review the 10 mistakes that should be avoided when injecting botulinum toxin. We also reflect on how treatment with botulinum toxin influences us through our facial expressions, both in terms of how we feel and what others perceive.

Decreased face primary motor cortex (face-M1) excitability induced by noxious stimulation of the rat molar tooth pulp is dependent on the functional integrity of face-M1 astrocytes.

Acute inflammatory dental pain is a prevalent condition often associated with limited jaw movements. Mustard oil (MO, a small-fiber excitant/inflammatory irritant) application to the rat molar tooth pulp induces increased excitability (i.e., central sensitization) of trigeminal medullary dorsal horn (MDH) nociceptive neurons that can be modulated by MDH application of the astrocytic inhibitor methionine sulfoximine (MSO). The objectives of the study were to determine whether MO application to the rat right maxillary first molar tooth pulp affects left face-M1 excitability manifested as altered intracortical microstimulation thresholds for evoking electromyographic activity in the right anterior digastric (RAD, jaw-opening muscle), and whether MSO application to face-M1 can modulate this MO effect. Under Ketamine general anesthesia, Sprague-Dawley male rats had a microelectrode positioned at a low-threshold (≤30 µA) face-M1 site. Then MO (n = 16) or control solution (n = 16) was applied to the previously exposed tooth pulp, and RAD threshold was monitored for 15 min. MSO (0.1 mM, n = 8) or saline (n = 8) was then applied to the face-M1, and RAD thresholds were monitored every 15 min for 120 min. ANOVA followed by post hoc Bonferroni was used to analyze data (p < 0.05). Within 15 min of MO (but not control) pulp application, RAD thresholds increased significantly (p < 0.001) as compared to baseline. One hour following MSO (but not saline) application to the face-M1, RAD thresholds decreased significantly (p = 0.005) toward baseline. These novel findings suggest that acute inflammatory dental pain is associated with decreased face-M1 excitability that may be dependent on the functional integrity of face-M1 astrocytes and related to mechanisms underlying limited jaw movements in acute orofacial pain conditions.

Half-mirror biofeedback exercise in combination with three botulinum toxin A injections for long-lasting treatment of facial sequelae after facial paralysis.

OBJECTIVES/HYPOTHESIS: The present study was conducted to develop a new method for maintaining the effect of botulinum toxin treatment for facial sequelae. We used a combination strategy including the administration of botulinum toxin three times at 6-8-month intervals followed by daily newly developed half-mirror biofeedback rehabilitation for about 2 years from the first injection. STUDY DESIGN: This was a prospective study. METHODS: Seventeen patients with unilateral facial palsy for >1 year were included in the study. The amount injected per site varied from 1.5 to 3 U. The purpose of the first injection was to reduce the most inconvenient facial problem such as facial synkinesis or hyperkinetic movement at the points of the periocular area and the zygomaticus major and minor muscles with an average dosage of 17.4 ± 13.9 U. The second injection was to enhance facial symmetry at prominent hypertrophic areas on the contralateral side with 36.5 ± 15.4 U, and the third injection was to add cosmetic configuration at the points of deep furrows and creases caused by facial muscular hyperkinesis or atrophy with 15.6 ± 8.4 U. RESULT: After three injections of botulinum toxin A and 2 years of half-mirror biofeedback exercises, all patients showed marked relief of facial synkinesis and facial asymmetry. Before treatment, the mean ± standard deviation (SD) Sunnybrook (SB) score was 36.8 ± 8.76. After the first injection, the score increased by 11.4. After the second injection, the score increased by 14.6; it further increased by 15.6 after the third injection. CONCLUSION: This facial rehabilitation strategy, consisting of three injections of botulinum toxin and half-mirror biofeedback exercises, proceeds over the course of 2 years and offers a long-lasting cure for facial synkinesis and facial symmetry as well as improved facial aesthetics.

Anatomical position of hyaluronic Acid gel following injection to the infraorbital hollows.

PURPOSE: To examine with histology the anatomical location of hyaluronic acid gel injected to the infraorbital hollows of cadaver specimens. METHODS: The authors dissected 5 fresh hemifacial cadaver specimens following preperiosteal injection of hyaluronic acid gel to the infraorbital hollows. Following tissue fixation, full-thickness soft tissue sections were obtained along the medial, central, and lateral lower eyelid/midface of each specimen. Histologic examination of the anatomical location of hyaluronic acid gel was performed using hematoxylin and eosin and Hale colloidal iron stains. RESULTS: Histologic examination of the central and lateral lower eyelid/midface sections revealed a significant portion of hyaluronic acid gel in either a postorbicularis or a subcutaneous plane in 8 of 10 sections. Only 2 sections displayed hyaluronic acid gel solely within a preperiosteal plane. The medial sections revealed hyaluronic acid gel resting in either a preperiosteal or an intraorbicularis plane. Soft tissue structures such as deep fat compartment septa and the orbicularis oculi muscle appeared to play a significant role in influencing the resting position of hyaluronic acid gel. CONCLUSIONS: In most specimens, the location of a significant portion of hyaluronic acid gel following injection to the infraorbital hollows differed from the intended injection plane. Soft tissue structures including fat compartment septa and the orbicularis oculi muscle appear to influence the resting position of hyaluronic acid gel. Careful attention should be used to avoid overfilling the thin soft tissue layers of the medial infraorbital hollows or tear trough.

Botulinum injection for the management of myofascial pain in the masticatory muscles. A prospective outcome study.

We prospectively analysed the outcome after botulinum injection in patients who did not recover after conservative measures to manage masticatory myofascial pain, and who were not willing to take low dose tricyclic antidepressants as a muscle relaxant. We prospectively 62 patients were assessed with visual analogue scores (VAS) for pain on the affected side before, and 6 weeks after botulinum injection(s) (50 units Dysport in up to 3 sites), and measured mouth opening in mm. Of those treated 49 (79%) showed at least some improvement (pain reduced by more than 25%). Patients reported more than a 90% reduction in the VAS for 25 (30%) of the 84 sides of the face treated. Only 22 of the 62 patients had more than one course of treatment to the same side. Interincisal distance improved by a mean/median of 0.9 mm (p<0.03) after treatment. Side effects included 3 cases of temporary weakness of a facial muscle. Ranking the VAS pain scores using the Wilcoxon test before and after injection showed a significant reduction in pain (median change -29.5, interquartile range -53 to -16, p<0.0001). The treatment significantly improved patients' pain scores and the overall mean/median reduction in pain was 57%. Botulinum injection does not guarantee complete resolution of myofascial pain, but it usually has some beneficial effect in improving the symptoms, and should be considered as an alternate treatment for masticatory myofascial pain if conservative methods have failed.

Systemic pregabalin attenuates sensorimotor responses and medullary glutamate release in inflammatory tooth pain model.

Our previous studies have demonstrated that application of inflammatory irritant mustard oil (MO) to the tooth pulp induces medullary glutamate release and central sensitization in the rat medullary dorsal horn (MDH), as well as nociceptive sensorimotor responses in craniofacial muscles in rats. There is recent evidence that anticonvulsant drugs such as pregabalin that influence glutamatergic neurotransmission are effective in several pain states. The aim of this study was to examine whether systemic administration of pregabalin attenuated glutamate release in the medulla as well as these nociceptive effects reflected in increased electromyographic (EMG) activity induced by MO application to the tooth pulp. Male adult rats were anesthetized with isofluorane (1.0-1.2%), and jaw and tongue muscle EMG activities were recorded by needle electrodes inserted bilaterally into masseter and anterior digastric muscles and into the genioglossus muscle, and also the medullary release of glutamate was assessed by in vivo microdialysis. Pregabalin or vehicle control (isotonic saline) was administered 30 min before the pulpal application of MO or vehicle control (mineral oil). Application of mineral oil to the maxillary first molar tooth pulp produced no change in baseline EMG activity and glutamate release. However, application of MO to the pulp significantly increased both the medullary release of glutamate and EMG activity in the jaw and tongue muscles for several minutes. In contrast, pre-medication with pregabalin, but not vehicle control, significantly and dose-dependently attenuated the medullary glutamate release and EMG activity in these muscles after MO application to the tooth pulp (analysis of variance (ANOVA), p<0.05). These results suggest that pregabalin may attenuate the medullary release of glutamate and associated nociceptive sensorimotor responses in this acute inflammatory pulpal pain model, and that it may prove useful for the treatment of orofacial inflammatory pain states.

Reversal of haloperidol-induced orofacial dyskinesia by Murraya koenigii leaves in experimental animals.

CONTEXT: Orofacial dyskinesia (OD) is a late complication of prolonged neuroleptic treatment characterized by involuntary movements of the oral region. Chronic treatment with neuroleptics leads to development of vacuous chewing movements (VCMs). VCMs in rats are widely accepted as an animal model of OD. OBJECTIVE: To study the effect of Murraya koenigii L. (Rutaceae) leaves on haloperidol-induced OD. MATERIALS AND METHODS: Effect of alcohol extract of M. koenigii leaves (EEMK) and its alkaloid fraction (AMK) on body weight, locomotor activity, behavioral parameters, such as VCMs, tongue protrusions (TPs), orofacial bursts (OBs), and biochemical parameters such as antioxidant defense enzymes levels [superoxide dismutase (SOD) and catalase (CAT)], glutathione (GSH) levels, and lipid peroxidation (LPO) in the forebrain region was studied in haloperidol-treated rats. RESULTS: Rats chronically treated with haloperidol (1 mg/kg, i.p., 21 days) significantly decreased locomotion and developed VCMs, OBs, and TPs. Biochemical analysis reveals that chronic haloperidol-treated rats also showed decreased levels of SOD and CAT. Chronic haloperidol treatment significantly induced LPO and decreased the forebrain GSH levels in the rats. Co-administration of EEMK (100 and 300 mg/kg, p.o.) and AMK (30 and 100 mg/kg, p.o.) along with haloperidol significantly reversed the effect on locomotion. EEMK and AMK significantly reversed the haloperidol-induced decrease in forebrain SOD and CAT levels in rats and significantly reduced the LPO and restored the decreased GSH levels by chronic haloperidol treatment. CONCLUSION: The study concludes that M. koenigii could be screened as a potential drug for the prevention or treatment of neuroleptic-induced OD.

Genistein attenuates genioglossus muscle fatigue under chronic intermittent hypoxia by down-regulation of oxidative stress level and up-regulation of antioxidant enzyme activity through ERK1/2 signaling pathway.

OBJECTIVE: This study aims to investigate the effects of genistein on contractile properties of genioglossus under chronic intermittent hypoxia (CIH) conditions and its relationship with oxidative stress, antioxidant enzyme, and ERK1/2 signaling pathway. MATERIALS AND METHODS: Fifty female Sprague-Dawley rats were randomly divided into five groups 1 week after ovariectomy: the normal control group, the CIH group, the CIH with low-dose, medium-dose, and high-dose genistein groups. Rats in the latter four groups were exposed to CIH for 5 weeks. Twitch tension, tetanic tension, and fatigue resistance of genioglossus were investigated. Malondialdehyde (MDA) and mitochondrial reactive oxygen species (ROS), enzymatic activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and ERK1/2 were detected. RESULTS: Muscle fatigue resistance and enzymatic activity of GPx, CAT, and SOD were reduced after CIH exposure and improved by different doses of genistein at different degrees. CIH increased the level of ROS and MDA, and they were returned to normal by genistein. The expression of phospho-ERK1/2 is opposite to the changes in muscle fatigue resistance. CONCLUSION: Chronic intermittent hypoxia decreases fatigue resistance of genioglossus, and genistein treatment reverses the fatigability of genioglossus by down-regulation of oxidative stress level and up-regulation of antioxidant enzymatic activity probably through ERK1/2 signaling pathway.

[Combined application of electric myo-stimulation and meso-therapy for the correction of age-related changes of the facial skin].

The objective of the present study was to evaluate effects of mesotherapy (MT) and electrostimulation (EMS) on age-related changes of the facial skin. The secondary objective was to identify factors influencing the therapeutic efficiency of these methods. The study included 60 women aged from 30 to 59 years. All the patients were examined prior to the onset and in the end (after one month) of the corrective treatment. Facial skin conditions were assessed using a Skin XP Pro system and skin microcirculation by laser Doppler flowmetry (LDF). The psychological status of the patients was evaluated with the help of the Well-being-Activity-Mood test. After the primary examination, the participants of the study were randomly divided into two groups. Group 1 (n=30) included women treated by MT and EMS, the control group 2 (n=30) was comprised of the patients who did not receive the above treatment. The results of the study indicate that combine MT + EMS therapy significantly improves the state of facial skin, decreases its pigmentation, reduces the number and depth of wrinkles, enhances skin moisture, improves its elasticity and decreases porosity. Dynamics of these parameters and overall effect of correction were shown to correlate with the severity of skin changes before the treatment. Age-related changes in the facial skin were especially well-apparent in women with the lowered activity level and impaired mood. Characteristics of mood in the course of therapeutic correction correlated with dynamics of skin smoothness and elasticity.

Assessment of the effect of the use of laser light or dantrolene on facial muscle under occlusal wear: a Raman spectroscopic study in a rodent model.

OBJECTIVE: The aim of the present study was to use Raman spectroscopy to measure levels of CaPi in muscles under occlusal wear and treated with laser phototherapy (LPT) or muscle-relaxant therapy or both on rodents. BACKGROUND: The etiology of temporomandibular disorders is multifactorial. Malocclusion may influence the masticatory muscles, causing fatigue. A major type of fatigue is the metabolic, caused by the increased accumulation of metabolites such as inorganic phosphate. Raman spectroscopy allows nondestructive analysis of the biochemical composition of tissues. METHODS: The 30 male Wistar rats were randomly divided into three groups: occlusal wear (G-1), occlusal wear + LPT (G-2), and occlusal wear + muscle relaxant (G-3). Ten untreated animals were used for baseline data. Under intraperitoneal general anesthesia, animals of groups 1, 2, and 3 had unilateral amputation of molar cusps to simulate an occlusal-wear situation. The masseter muscle of G-2 received LPT (lambda830 nm, 4 J/cm(2), 40 mW, phi approximately 2 mm) after the procedure and repeated every other day for 14-30 days. Animals of G-3 were treated with a daily injection of dantrolene (2.5 mg/kg in 0.5 ml of H(2)O) beginning 24 h after cusp removal. Animals were killed with an overdose of general anesthetics at days 14 and 30 after cusps removal, and the ipsilateral masseter muscle was excised and divided into two parts. One part was routinely processed and underwent histologic analysis; the other was kept in liquid nitrogen for Raman spectroscopy. The mean value of the intensity of the peak 958 per centimeter was determined. RESULTS: No morphologic changes were seen. Raman analysis showed significantly less Raman intensity in the laser group at 30 days (p < 0.01). CONCLUSION: Occlusal wear did not caused morphologic alterations in the masseter muscle but resulted in changes of the levels of CaP(i) that were less compromising when the laser light was used.

[Simultaneous injection of lidocaine improves predictability of effect of botulinum toxin]. / Simultane Injektion mit Lidocain verbessert die Vorhersehbarkeit des Effekts von Botulinumtoxin.

Injection of botulinum toxin A is a common procedure in Otorhinolaryngology, Ophtalmology and Neurolgy. Recently botulinum toxin treatment has been described to improve woundhealing after facial injuries. The lack of immediate predictibility of the ensuing paralytic effect is one of the daily challenges of botulinum toxin injections. In the present report we describe the simultaneous injection of botulinum toxin and lidocaine with the purpose to gain immediate feed back of the treatment effect. Furthermore we recommend the addition of adrenalin to reduce possible systemical toxin circulation.

Botulinum toxin and the facial feedback hypothesis: can looking better make you feel happier?

The facial feedback hypothesis suggests that muscular manipulations which result in more positive facial expressions may lead to more positive emotional states in affected individuals. In this essay, we hypothesize that the injection of botulinum toxin for upper face dynamic creases might induce positive emotional states by reducing the ability to frown and create other negative facial expressions. The use of botulinum toxin to pharmacologically alter upper face muscular expressiveness may curtail the appearance of negative emotions, most notably anger, but also fear and sadness. This occurs via the relaxation of the corrugator supercilii and the procerus, which are responsible for brow furrowing, and to a lesser extent, because of the relaxation of the frontalis. Concurrently, botulinum toxin may dampen some positive expressions like the true smile, which requires activity of the orbicularis oculi, a muscle also relaxed after toxin injections. On balance, the evidence suggests that botulinum toxin injections for upper face dynamic creases may reduce negative facial expressions more than they reduce positive facial expressions. Based on the facial feedback hypothesis, this net change in facial expression may potentially have the secondary effect of reducing the internal experience of negative emotions, thus making patients feel less angry, sad, and fearful.

Peribulbar anesthesia for blepharoplasty.

BACKGROUND: Peribulbar anesthesia for inferior blepharoplasty was used successfully in 788 selected cases over the past 9 years. This technique is largely accepted for ophthalmologic procedures, but is not yet specifically used for blepharoplasty. METHODS: In the past 9 years, 788 patients ages 36 to 77 years were submitted to inferior peribulbar anesthesia for blepharoplasty procedures. Of these patients, 623 (79%) were women and 165 (21%) were men. The anesthetic procedure is performed using a needle introduced at the junction of the medial two-thirds and the lateral third of the inferior orbital rim (point A). With the patient staring forward, the needle is introduced through the lid at point A. It enters the orbital cavity just above the orbital floor periosteum until the globe equator is minimally trespassed (depth, approximately 31 mm). There, 3 ml of the local anesthetic solution (2% lidocaine + 0.5% bupivacaine) is slowly injected. RESULTS: None of our treated patients reported pain or discomfort during or after the surgical procedure. Immediately after inferior peribulbar anesthesia, chemosis was observed in 17 cases (2.2%) and orbital hematoma in 3 cases (0.4%). Diplopia, or a slight imaging distortion lasting a few hours may occur after inferior peribulbar anesthesia. CONCLUSION: Inferior peribulbar anesthesia for blepharoplasty offers surprising results. The surgical procedures are performed pain free, leaving the patients completely relaxed and allowing an easier surgical procedure. This technique should be performed only by highly skilled anesthesiologists or surgeons with a perfect knowledge of the complex orbital anatomy.

The effect of a high-fat meal on the pharmacodynamics of a model lipophilic compound that binds extensively to triglyceride-rich lipoproteins.

A high-fat meal induces transient hyperlipidemia characterized by elevated triglyceride-rich lipoproteins (TRL) which are composed mainly of chylomicrons. The purpose of this work was to investigate the effect of this transient hyperlipidemia on the pharmacodynamics of lipophilic drugs, using DDT as a model compound since it binds extensively to TRL and has a distinct neurotoxic effect. The postprandial hyperlipidemia in rats was induced by oral administration of peanut oil and was monitored by measurement of plasma triglyceride levels. The control group received water instead of oil. The rats received a continuous intravenous infusion of DDT (10 mg/h) until onset of a predefined pharmacodynamic endpoint (facial muscle tremor). Plasma and brain samples were then obtained and assayed for DDT. Rats with postprandial hyperlipidemia required higher dose of DDT to induce onset of facial muscle tremor. At the pharmacodynamic endpoint, oil treated rats had significantly higher concentrations of DDT in plasma and in the chylomicron fraction, but DDT brain concentrations were the same in both groups. In conclusion, a high-fat meal induces postprandial hyperlipidemia that may significantly alter the pharmacological profile of lipophilic compounds that bind to TRL. This is due to alteration of the distribution characteristics of the lipophilic compound through its association with postprandial lipoproteins. However, this pharmacokinetic phenomenon did not affect the concentration-effect relationship at the site of action in the brain.

Peripheral mGluR5 antagonist attenuated craniofacial muscle pain and inflammation but not mGluR1 antagonist in lightly anesthetized rats.

The present study investigated the role of peripheral group I metabotropic glutamate receptors (mGluRs) in MO-induced nociceptive behaviour and inflammation in the masseter muscles of lightly anesthetized rats. Experiments were carried out on male Sprague-Dawley rats weighing 300-400 g. After initial anesthesia with sodium pentobarbital (40 mg/kg, i.p.), one femoral vein was cannulated and connected to an infusion pump for intravenous infusion of sodium pentobarbital. The rate of infusion was adjusted to provide a constant level of anesthesia. Mustard oil (MO, 30 microl) was injected into the mid-region of the left masseter muscle via a 30-gauge needle over 10s. After 30 microl injection of 5, 10, 15, or 20% MO into the masseter muscle, the total number of hindpaw shaking behaviour and extravasated Evans' blue dye concentration in the masseter muscle were significantly higher in the MO-treated group in a dose-dependent manner compared with the vehicle (mineral oil)-treated group. Intramuscular pretreatment with 3 or 5% lidocaine reduced MO-induced hindpaw shaking behaviour and increases in extravasated Evans' blue dye concentration. Intramuscular pretreatment with 5 mM MCPG, non-selective group I/II mGluR antagonist, or MPEP, a selective group I mGluR5 antagonist, produced a significant attenuation of MO-induced hindpaw shaking behaviour and increases in extravasated Evans' blue dye concentration in the masseter muscle while LY367385, a selective group I mGluR1 antagonist, did not affect MO-induced nociceptive behaviour and inflammation in the masseter muscle. These results indicate that peripheral mGluR5 plays important role in mediating MO-induced nociceptive behaviour and inflammation in the craniofacial muscle.

Intramuscular versus surface electromyography of the diaphragm for determining neuromuscular blockade.

We determined the neuromuscular blockade of 0.2 mg. kg(-1) mivacurium at the diaphragm by using two new methods of electromyographic (EMG) monitoring and compared it with acceleromyography of the orbicularis oculi (OO) and the corrugator supercilii (CS) muscle. After the induction of anesthesia in 15 patients undergoing gynecologic laparoscopic surgery, evoked EMG responses at the diaphragm were obtained by using skin electrodes at the back of the patient, placed lateral to T12/L1 or L1/L2, and a laparoscopically applied wire electrode inserted into the dorsolateral portion of the diaphragm. Acceleromyography at the right OO and the left CS was performed. The facial and phrenic nerves were stimulated transcutaneously (onset: every 10 s, offset: every 15 s, single twitch stimulation). Lag and onset time, peak effect, and clinical duration (time to reach 75% of control value and time to reach 90% of control value) were measured and the results were compared by using analysis of variance; P < 0.05 showed significant difference. Pearson's correlation test and the Bland-Altman test were used to compare the two diaphragmatic monitoring methods. Mean peak effects of >98% were reached at all sites. Onset times at diaphragm (skin, IM) were significantly (P < 0.005) shorter than at the CS or OO (100 +/- 14 s and 98 +/- 16 s vs 147 +/- 39 s, 185 +/- 38 s) without being statistically different between OO and CS. There was a good correlation of lag, onset time, time to reach 75% of control value, and time to reach 90% of control value (r = 0.8, 0.9, 0.8, and 0.75; P < 0.01) between the two diaphragmatic methods. Mean difference and limits of agreements are -2 +/- 15 s, 1 +/- 21 s, -1 +/- 2.3 min, and -2 +/- 3.4 min. We showed a shorter onset and clinical duration at the diaphragm in comparison with CS and OO. Two methods of EMG of the diaphragm correlated well and showed good comparability. The novel method of surface diaphragmatic EMG at the patient's back may be useful during routine clinical anesthesia.