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PubMed2001

[Repair of facial soft tissue defect using temporal flap pedicled with orbicularis oculi muscle].

OBJECTIVE: To probe into the methods and effects of small soft tissue defect of facial area, nose and eyelid repaired by temporal island flap pedicled with orbicularis oculi muscle. METHODS: From 1994 to 1999, 12 cases with cicatricial ectropion of eyelid, scar in nose and facial area or facial mole were repaired by temporal flap pedicled with orbicularis oculi muscle. The maximal area of skin flap was 3 cm x 5 cm. RESULTS: All the skin flaps were survived after operation. Six cases were followed up from 6 months to 4 years, the results were satisfied. There were no secondary deformity or scar formation in the donor site. CONCLUSION: The blood supply of orbicularis oculi muscle is plentiful. It is a reliable method to repair of small facial tissue defect using temporal island flap pedicled with orbicularis oculi muscle. But in bigger facial soft tissue defect, it should be cautious.

Adolescent↗
PubMed2002

Combined intraoral and lateral temporal approach for palatal malignancies with temporalis muscle reconstruction.

OBJECTIVE: To evaluate the use of a combined lateral temporal fossa and intraoral approach to resect palatal carcinomas and the use of a temporalis myofascial flap for reconstruction. DESIGN: Retrospective chart review of a case series. SETTING: Tertiary university referral hospital. PATIENTS: Sixteen patients underwent a combined approach for resection of palatal carcinoma; 5 of the 16 were edentulous. Six types of tumors were treated: adenoid cystic carcinoma (3 patients), low-grade mucoepidermoid carcinoma (5 patients), squamous cell carcinoma (3 patients), polymorphous low-grade adenocarcinoma (2 patients), osteosarcoma (1 patient), ameloblastoma (1 patient), and hyalinizing clear cell carcinoma (1 patient). MAIN OUTCOME MEASURES: The postoperative diet, velum competence, flap viability, complications, and survival. RESULTS: Fifteen (94%) of 16 patients were able to resume their preoperative diets. No velopharyngeal insufficiency was encountered. All flaps survived and none required repeated surgical intervention. Five patients developed serous otitis media and 2 patients required flap revision secondary to posterior choanal obstruction. One patient died of complications unrelated to the procedure. CONCLUSIONS: A combined intraoral and lateral temporal fossa approach allows for (1) en bloc resection of palatal malignancies along with resection of involved pterygoid muscles, (2) isolation and resection of descending palatine nerves and the proximal second division of the trigeminal nerve, and (3) primary reconstruction of the palatal defect by means of the temporalis muscle rotated into the operative defect. This method is especially useful in treating patients with perineural spread of palatal carcinoma, and in those who are edentulous.

Adult↗
PubMed2001

Local perfusion and metabolic demand during exercise: a noninvasive MRI method of assessment.

A noninvasive magnetic resonance imaging (MRI) method to assess the distribution of perfusion and metabolic demand (Q/VO(2)) in exercising human skeletal muscle is described. This method combines two MRI techniques that can provide accurate multiple localized measurements of Q/VO(2) during steady-state plantar flexion exercise. The first technique, (31)P chemical shift imaging, permits the acquisition of comparable phosphorus spectra from multiple voxels simultaneously. Because phosphocreatine (PCr) depletion is directly proportional to ATP hydrolysis, its relative depletion can be used as an index of muscle O(2) uptake (VO(2)). The second MRI technique allows the measurement of both spatially and temporally resolved muscle perfusion in vivo by using arterial spin labeling. Promising validity and reliability data are presented for both MRI techniques. Initial results from the combined method provide evidence of a large variation in Q/VO(2), revealing areas of apparent under- and overperfusion for a given metabolic turnover. Analysis of these data in a similar fashion to that employed in the assessment of ventilation-to-perfusion matching in the lungs revealed a similar second moment of the perfusion distribution and PCr distribution on a log scale (log SD(Q) and log SD(PCr)) (0.47). Modeling the effect of variations in log SD(Q) and log SD(PCr) in terms of attainable VO(2), assuming no diffusion limits, indicates that the log SD(Q) and log SD(PCr) would allow only 92% of the target VO(2) to be achieved. This communication documents this novel, noninvasive method for assessing Q/VO(2), and initial data suggest that the mismatch in Q/VO(2) may play a significant role in determining O(2) transport and utilization during exercise.

Adult↗
PubMed1988

Blood flow distribution and its temporal variability in stimulated dog gastrocnemius muscle.

The distribution of blood flow in skeletal muscle stimulated to rhythmic isotonic contractions was studied by injections of radioactive microspheres into the arterial supply in 8 gastrocnemius muscles (mean weight 84 g) of 6 anesthetized dogs (20-25 kg body weight). The distribution of 10 micron microspheres in regions of about 0.5 g was very similar to that of the standard 15 micron microspheres, whereas that of 25 micron microspheres was more uneven. The coefficient of variation (CV = SD/mean) of the ratio of simultaneously injected 10 micron and 15 micron microspheres, 0.12, was taken as the inherent scatter of the method. The average spatial distribution inequality of 10-15 micron microspheres corresponded to a CV of 0.45 and the specific local blood flow inhomogeneity to a CV = 0.43 ( = square root 0.45(2) - 0.12(2], but there were marked differences between muscles. At equal blood flow levels, the inhomogeneity during reactive hyperemia was similar to that observed during stimulation. The temporal variability of blood flow in individual muscle pieces was obtained from the comparison of fractional trapping of 4 to 5 differently labeled microspheres injected at intervals of 2 min into steadily stimulated muscles. The mean CV for the variations in time was 0.23 and that corrected for methodological scatter, 0.19, but the differences in the extent of temporal blood flow changes among muscle pieces within a muscle and between different muscles were large. The presence of considerable spatial and temporal variations of blood flow in exercising muscle during apparent steady state may be important in limiting and/or modulating tissue O2 supply.

Animals↗
PubMed1980

Pain, tenderness and strength of human mandibular elevators.

In terms of the mean voltage during maximal bite in the intercuspal position we compared the strength of the temporal and masseter muscles of 39 patients with functional disorders of the chewing apparatus and 45 controls. Maximal electrical activity was significantly stronger in the controls than in the patients. Differences between the two samples with respect to sex, age, number of opposing teeth in contact and the presence of pain and tenderness tended to favor stronger activity in the controls. However, the different levels of electrical activity, especially in the case of the masseter muscles, could only be accounted for on the basis of a difference in maximal strength. We suggest that the weaker elevator muscles of the patients was a predisposing factor making these muscles less fit to endure hyperactivity induced psychologically or as a reflex response to occlusal interferences and functional disorders of the temporomandibular joints or other elements of the oral neuromuscular system. The sample of controls had much stronger elevators, less susceptible to such hyperactivity.

Adolescent↗
PubMed2006

Heterogeneous postnatal transitions in myosin heavy chain isoforms within the rabbit temporalis muscle.

Postnatal changes in the fiber type composition and fiber cross-sectional area were investigated in the superficial (TEM1) and deep (TEM23) temporalis of male rabbits. It was hypothesized that, due to the transition from suckling to chewing during early postnatal development, the proportion of fast fiber types would decrease, while the proportion of fibers positive for myosin heavy chain (MyHC) cardiac alpha would increase, and that, due to the influence of testosterone during late postnatal development, the proportion of these alpha fibers would decrease again. Classification of the fibers types was performed by immunohistochemistry according to their MyHC content. The proportion of alpha fiber types significantly increased in both muscle portions from 2% and 8% for TEM1 and TEM23 at week 1 to 29% and 54% at week 8, respectively,. While in TEM1 the proportion of this fiber type did not change thereafter, it decreased again to 27% in TEM23 at week 20. The change for the fast fiber types was opposite to that of the alpha fiber types. Significantly more MyHC IIX fibers were found in TEM1 than in TEM23 in adult rabbits. In the first 8 weeks, the cross-sectional areas of all fibers increased. After this period, only MyHC cardiac alpha + I fibers continued to increase significantly. It was concluded that there are developmental differences in the myosin heavy chain transitions of the two portions of the temporalis muscle.

Animals↗
PubMed1996

Sensitivity of the jaw-jerk reflex in patients with myogenous temporomandibular disorder.

Changes in the activity of human jaw-elevator muscles related to the mandibular stretch (jaw-jerk) reflex could be involved in the aetiology of temporomandibular disorders (TMD). In order to investigate whether there are differences in the sensitivity of the jaw-jerk reflex between myogenous TMD patients (n = 10) and gender- and age-matched controls (n = 10), jaw-jerk reflexes were elicited under standardized conditions. By measuring the reflex with bipolar surface electromyography (EMG), reflex sensitivity was determined from relations between reflex amplitude and jaw displacement from the masseter and the anterior temporalis muscles. Reflex amplitude and background EMG activity were normalized with respect to the maximal voluntary contraction (MVC) to correct for differences in the thickness of soft tissues overlying the muscle or in electrode placement. In addition to normalization with respect to MVC, for the patients, normalization was also applied with respect to a MVC that was scaled by multiplying values by the ratio of the mean MVC of controls to the mean MVC of patients. At a constant level of background EMG activity, the reflex sensitivity can be determined from the slope (reflex gain) and x-intercept (reflex threshold) of the reflex amplitude-jaw displacement relation. No significant differences between patients and controls were found for the gain or threshold values of either the masseter or the anterior temporalis muscles with a univariate analysis of variance. It is concluded that jaw-jerk reflex sensitivity is not significantly changed in myogenous TMD patients. Therefore, the fusimotor system probably does not play a part in the perpetuating myogenous TMD.

Action Potentials↗
PubMed1986

The versatility of the temporalis muscle flap in reconstructive surgery.

The temporalis muscle flap recently has become widely used in reconstructive surgery of the maxillo-facial region, although it was described around the turn of the century. We review the work which led to its development, and to illustrate its versatility, we describe some of its uses.

Ankylosis↗
PubMed1995

Intraoral defect coverage with muscle flaps.

PURPOSE: This study investigated whether wound healing after the use of purely muscular flaps for intraoral defect coverage is negatively influenced by insipient muscular atrophy and the absence of a covering layer. MATERIALS AND METHODS: In an experimental study, microsurgical transplantation of muscle flaps from the anterior abdominal wall was carried out in 18 Lewis rats. A nerve anastomosis for motor reinnervation was not performed. Atrophy of the muscle flaps was determined by measuring the reduction of their size and weight after 3, 8, and 20 weeks. In the clinical part of the study, free muscle transplants from different donor regions (vastus lateralis, pectoralis major, internal oblique, and temporalis muscles) were used for defect coverage in various areas of the oral cavity. To study epithelization, punch biopsy specimens from the muscle surface were taken at periods of 2 to 4 weeks up to 6 months for histologic evaluation. Final evaluation of reconstruction results with special regard to speech, tongue mobility, mouth opening, chewing, and swallowing took place after 6 months. RESULTS: In the experimental study, average weight loss of the muscle flaps was 67% after 20 weeks, and the remaining surface area was 71%. The number of myocytes was only about 30% compared with control muscles, and parts of the flap appeared as a thin fibrous membrane. Clinically, this atrophy led to restricted mobility in such areas as the floor of the mouth, the buccal plane, and the tongue. Muscle flaps covering solid structures such as bones or reconstruction plates adapted well to the transplant bed, and the atrophy of the muscle led to no constriction of the surrounding tissue. Atrophy also did not have a negative effect when muscle flaps were placed in the region of the pharyngeal wall. Epithelization started from the edges after 2 weeks and was concluded after 8 weeks in all transplants if no additional radiation was performed. The muscle tissue was sufficiently resistant so that infection, fistulization, and necrosis did not occur. CONCLUSIONS: Muscle flaps undergo considerable atrophy with a cicatricial transformation and reduction of flexibility. Despite these disadvantages they can be used in the hard palate, the alveolar crest, and in the pharyngeal wall without causing functional restriction. Because of constriction of the surrounding tissues, mobile areas such as the buccal plane, the floor of the mouth, and the tongue are not suitable as sites for muscle transplants.

Abdominal Muscles↗
PubMed1995

Functional characteristics of retrognathic patients before and after mandibular advancement surgery.

PURPOSE: The purpose of this investigation was to compare morphologic parameters and functional performance between controls and a sample of patients with mandibular retrognathia prior to surgical correction, and to examine how oral motor function adapts after treatment. PATIENTS AND METHODS: Twenty-four retrognathic female patients were compared with 26 female controls before and up to 3 years after mandibular advancement surgery. Measures of skeletal morphology, mandibular range of motion, maximum isometric bite force, and levels of electromyographic activity in the anterior and posterior temporalis and masseter muscles during isometric bites were made on all subjects over time. One-way analysis of variance was used to compare the controls, the patients before surgery, and the patients after surgery. RESULTS: Surgical lengthening of the mandible averaged 7.3 mm, bringing most skeletal measures into the normal range. There were no significant differences in jaw muscle mechanical advantage between patients and controls before surgery, but surgery significantly reduced mechanical advantage of the anterior temporalis and masseter muscles. Jaw hypomobility was apparent at 6 weeks after surgery, but returned to normal values within 12 to 24 months. Before surgery the patients had maximum isometric bite forces less than half those of controls. Bite forces steadily increased after surgery, approaching normal values within 2 years. Before surgery the patients' muscle activity levels per unit of bite force were equivalent to those of controls or somewhat higher. After surgery some of the patients' muscles had significantly lower levels of muscle activity per unit of bite force than did controls. CONCLUSION: The results of this study suggest that correction of mandibular retrognathia by mandibular advancement surgery produces some significant functional benefits.

Adolescent↗
PubMed2005

Reproducibility of surface EMG variables in isometric sub-maximal contractions of jaw elevator muscles.

The aims of this study were: (1) to develop and assess reproducibility of a new method for measuring masticatory force in the intercuspal position; (2) to test the reproducibility of surface EMG signal amplitude and spectral variables in constant force contractions of jaw elevator muscles and its dependency on inter-electrode distance. The study was performed on the masseter and temporalis anterior muscles of both sides of nine healthy volunteers. An intraoral compressive-force sensor was used to measure maximal voluntary contraction forces in the intercuspal position and to provide a visual feedback on sub-maximal forces to the subject. Three experimental sessions were performed in three days. In each session, three isometric contractions at 80% of the maximal force were sustained by the subjects for 30s. The intra-class correlation coefficient (ICC) of the maximal force measure was 71.9%. ICC of average rectified value and mean power spectral frequency of the EMG signal increased with inter-electrode distance, with values larger than 70% with 30 mm inter-electrode distance. It was concluded that surface EMG variables measured in isometric contractions of the jaw elevator muscles with the proposed force recording system show good reproducibility for clinical applications when a 30 mm inter-electrode distance is considered.

Adult↗
PubMed2004

Masticatory function in retrognathic patients, before and after mandibular advancement surgery.

PURPOSE: Mandibular retrognathia is a dentofacial deformity that can be surgically corrected. The purpose of this study was to evaluate the influence of orthognathic surgery on masticatory function in a sample of retrognathic patients and to compare these findings with those of controls. PATIENTS AND METHODS: Eleven retrognathic patients were tested before and 1 to 1.5 years after mandibular advancement surgery and compared with 12 controls. The median particle size after chewing a silicon rubber test food, the maximum bite force, and the electromyographic activity (EMG) of the anterior temporalis and the masseter muscles during isometric clenching and during chewing were determined. Patients, before and after treatment, and controls were statistically compared by analysis of variance. RESULTS: Surgical correction of mandibular retrognathia did not change chewing efficiency, maximum bite force, EMG during maximal clenching, EMG during chewing, or the EMG/bite-force relationship. Compared with controls, the chewing efficiency, maximum bite force, EMG during maximal clenching, and EMG during chewing values were lower. No difference for the EMG/bite-force ratio at maximal clenching was found, indicating similar muscle efficiency for patients and controls. However, in the range of 10% to 40% of the maximum bite force, the slope of the EMG/bite-force regression line was steeper for the patients than for the controls, indicating decreased muscle efficiency for patients. CONCLUSIONS: The results of this study suggest that in retrognathic patients, function of the masticatory system is impaired. Oral function was not influenced by mandibular advancement surgery.

Adult↗
PubMed1998

Stimulation of the neostriatum induces jaw-opener muscle activity, but not jaw-closer muscle activity: an electromyographic study in the rat.

Microstimulation was carried out at 36 sites in the dorsal striatum in lightly anesthetized rats. Only at two sites, microstimulation of 40 microA induced a considerable EMG activity in the jaw-opener (anterior digastric muscle). No activity was evoked in the jaw-closers (masseter and temporalis muscles). The effective sites were confirmed to be localized in a small central region of the striatum at a level corresponding to the caudal end of the anterior commissure. The effect was ascribed to excitation of a small cluster of striatal neurons, rather than to antidromic activation of cerebral cortical neurons through their axons within the striatum. (1) The effect was abolished after destruction of neurons in the striatal region by injecting kainic acid. (2) The effect was not influenced by ablation of the neocortex. (3) Microinjection of kainic acid into the striatal region also induced the similar muscle activity in the jaw-opener, but not in the jaw-closers.

Animals↗
PubMed1998

Electromyography during chewing movement in patients with anterior disc displacement of the temporomandibular joint.

The purpose of this study was to investigate the value of electromyography in patients with anterior disc displacement (ADD) of the temporomandibular joint (TMJ). Electromyography (EMG) during chewing movement was evaluated in 48 women with unilateral ADD of the TMJ (21 patients with ADD with reduction and 27 with ADD without reduction). As a control group, 31 women without TMJ dysfunction were evaluated. The duration of contraction, latency, cycle time, and integrated value on the EMG were measured in the patients and controls. There were significant differences between the patients and controls in the duration of contraction, cycle time, and integrated value. However, there were no differences in any measurements between the two subgroup patients. EMG appeared to be a method of documenting that masticatory function was impaired in patients with ADD.

Adolescent↗
PubMed2000

EMG-force relationships are influenced by experimental jaw-muscle pain.

The bite force at different levels and the corresponding electromyographic (EMG) activity of the masseter and anterior temporalis muscles were recorded in 12 healthy subjects in order to evaluate the modulation of EMG-force curves by a standardized painful stimulus. Hypertonic saline (5%) was infused into the right masseter muscle for up to 15 min to induce pain. The pain intensity was scored continuously by the subjects on a 10-cm visual analogue scale (VAS). Subjects were asked to bite on a force transducer at the maximum voluntary bite force (MVBF). They were then asked to bite at submaximum levels of 12, 25, 37, 50, 67, 75 and 87% of MVBF. The biting was performed in three different positions (right first molar, left first molar and incisor) before, during and after infusion. Hypertonic saline caused moderate pain during infusion (mean VAS +/- s.e.m. = 6.5+/-0.5 cm). Both the MVBF and the maximum EMG activity in the right masseter and the left anterior temporalis muscles were significantly decreased during muscle pain when the subjects bit on the painful side. The EMG-force curves could be fit by linear relationships. The slope of the curve became less steep in the right masseter muscle during and after painful biting in every position. The results suggest that tonic saline-induced jaw-muscle pain is able to modulate the motor unit recruitment pattern of the jaw-closing muscles on the painful side. The main effect of pain in this experiment was an inhibition of static EMG activity.

Adult↗
PubMed2002

A modified temporalis transfer in facial reanimation.

A modified surgical procedure for temporalis transfer in facial reanimation of five consecutive cases is presented. Instead of the traditional stripping of the temporalis from its origin, its attachment at the coronoid removed, and to its end, the harvested fascia lata graft was sutured to lengthen the muscle's action. These fibres were then passed to the Orbicularis Oculi and Oris to aid in reanimation and to improve their tone. The procedure is less extensive, provides a direct line of pull with good functional results, no muscle atropy since vascularity and innervation is maintained. No complaints of paresthesia, hyposthesia or scar on donor leg was noticed. None of the patients required a revision of surgery for unacceptable contour or asymmetry. This simple procedure has helped reconstruction of natural symmetrical smile with highly successful results.

Adult↗
PubMed2006

Effect of therapeutic jaw exercise on temporomandibular disorders in individuals with chronic whiplash-associated disorders.

OBJECTIVE: The aim of this study was to investigate the effect of a specific therapeutic jaw exercise on the temporomandibular disorders of patients with chronic whiplash-associated disorders. MATERIAL AND METHODS: Ninety-four consecutive patients with whiplash-related conditions were referred to and accepted for a treatment period at a center for functional evaluation and rehabilitation during 2001-2002. The patients followed a program of physical therapy, occupational therapy, and pain management. At the start of their stay, they were examined by a physician specialized in rehabilitation medicine and also by a dentist who performed a functional examination of the stomatognathic system. Of the 93 patients who accepted participation in the study, 55 were diagnosed with temporomandibular disorders and chronic whiplash-associated disorders in accordance with the inclusion criteria. They were randomized into a jaw exercise group (n = 25), who performed specific therapeutic jaw exercises, and a control group (n = 30). Both groups undertook the whiplash rehabilitation program at the center. RESULTS: There were no inter- or intra-group differences in symptoms and signs of temporomandibular disorders at baseline, nor at the 3-week and 6-month follow-ups, except for an increase of maximum active mouth-opening capacity in the control group. CONCLUSIONS: In conclusion, the therapeutic jaw exercises, in addition to the regular whiplash rehabilitation program, did not reduce symptoms and signs of temporomandibular disorders in patients with chronic whiplash-associated disorders.

Adult↗