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PubMed1994

Localization of experimental brain tumors in MRI by gadolinium porphyrin.

The contrast between edema and F98 glioma in rat brain was distinctly enhanced in T2-weighted MRI (TE 130 ms, TR 3 s) by intraperitoneal injection of the synthetic gadolinium-porphyrin complex, GdTPPS. The T1 relaxation time of the gliomas was selectively shortened by about 50% from 1339 +/- 109 ms to 628 +/- 106 ms, and the T2 relaxation time was shortened by about 35% from 86 +/- 6 ms to 57 +/- 5 ms. The relaxation times of normal tissues under investigation (cortex, corpus callosum, temporal muscle, ventricles) were unaltered. Therefore, GdTPPS-application causes F98 gliomas to appear hyperintense in T1-weighted MRI and hypointense in T2-weighted MRI.

Animals↗
PubMed1993

Jaw-jerk reflex activity in relation to various clenching tasks in man.

In order to investigate whether the mandibular stretch (jaw-jerk) reflex is modulated in a task-dependent manner, jaw-jerk reflexes were elicited in eight subjects during clenching with unilateral and bilateral tooth support, respectively. The reflexes were examined in the electromyographic (EMG) activity recorded by means of surface electrodes and were elicited by means of small transient jaw displacements at a constant value of 80 microns. Low levels of background EMG were applied ranging from 1 to 30% maximal voluntary contraction (MVC) as controlled by means of visual feedback. Linear relationships were observed between reflex amplitude and level of background EMG. The slope in these relationships served as a measure of reflex gain. For the masseter as well as the anterior temporal muscles, the reflex gain, averaged over both sides, was larger during clenching with unilateral tooth support than with bilateral tooth support (P < 0.05). Furthermore, the gain was larger on the side without tooth support during unilateral clenching and larger on the side without visual feedback of elevator muscle activity during bilateral clenching. It can be concluded that the jaw-jerk reflex is modulated to subserve the stabilization of the mandible, with the reflex sensitivity being larger the more that alternative stabilizing factors such as mechanical tooth contact, visual feedback and feedback from periodontal pressure receptors around the teeth are lacking. The reflex modulation may be of functional importance in stabilizing the mandible during its movement in the chewing process, as the food is predominantly placed unilaterally between the antagonistic teeth during individual chewing cycles.

Adolescent↗
PubMed1994

Analysis of intracranial pressure pulse wave in experimental hydrocephalus.

Much has been written about the relationship between the pulse pressure (PP) of the intracranial pressure pulse wave (ICPPW) and ventricle dilatation. Some data suggest that high PP is the cause of ventricle dilatation, and other authors have reported that high PP results from decreased intracranial compliance. In order to clarify these points, the amplitude of PP and pressure-volume response (PVR: an indicator of intracranial compliance) were measured in bilateral ventricles using Hochwald's hydrocephalic model (right-left difference in ventricle size is clear due to hemicraniectomy). Hydrocephalus was induced by means of intracisternal injection of a kaolin powder solution to dogs. The mean ICP, amplitude of the PP, PVR and ventricle size (estimated by MR imaging) were evaluated in pathologic conditions induced by the following procedures. Group A, control: kaolin-induced hydrocephalus without craniectomy; group B: kaolin-induced hydrocephalus with right-sided craniectomy; group C: kaolin-induced hydrocephalus with right-sided craniectomy and dural resection; group D: kaolin-induced hydrocephalus with right-sided craniectomy, dura resection and temporal muscle resection. Using MR imaging, the same degree of symmetrical ventricle dilatation was identified in all groups except group D. Group D alone demonstrated a difference in ventricular size (craniectomy side > non-craniectomy side). There was no appreciable difference in mean ICP between any two groups. However, the amplitude of PP and the PVR decreased stepwise from group A to group D. The difference in the amplitude of the PP and PVR between the right and left ventricles was not significant in any group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Lifting of the eyebrows in blepharoplasties.

Excessive skin in the upper eyelid may be totally or partially a result of ptosis of the eyebrows. In this case, blepharoplasty corrects this deformity insufficiently and may even increase the sagging of the eyebrows, giving the face a sad expression. A technique for lifting the eyebrows during a blepharoplasty is presented. It consists of affixing the dermis and galea to the aponeurosis of the temporal muscle through a subgalean tunnel in the scalp. We believe that this is an anatomically based procedure, is easy to execute, has few complications, yields lasting results with hidden scars, and is of low cost. Among the 100 cases in which this technique was used, the majority showed highly satisfactory results.

Eyebrows↗
PubMed1984

Extent of thermal penetration of Nd-YAG laser--histological considerations.

The extent of thermal penetration of Nd-YAG laser was studied histologically. The material was obtained from seven cases of various types of intracranial and extracranial tumours and normal temporal muscle obtained at operation. After irradiation of the tumour surface with the laser, the tumours were removed and depth and width of pathological changes caused by heat were studied. Histologically, materials consisted of a vaporized surface, carbonized, vesicular, necrotic, oedematous layer and surrounding intact brain tumour tissue. There was a direct relationship between the thermal effect and the irradiated thermal energy (watt x exposure time x pulse number). The results showed that the thermal effect was limited to a depth of 6 to 10 mm from the irradiated surface when irradiated 4 times at the power of 90 watts for 2 seconds.

Adult↗
PubMed1989

The human temporo-mandibular joint: current anatomic and physiologic status.

The aim of this study was to take stock of current anatomic and physiologic knowledge of the human temporo-mandibular joint. Though the lateral pterygoid m. plays an essential role in joint movements, we believe that the small deep portion of the masseter and temporalis have a supplementary action in guiding the articular disc forward. The embryologists have demonstrated joint movements in the two-month embryo and at this stage there already exists a triple attachment of the temporalis, pterygoid and masseter to the disc.

Adult↗
PubMed1975

[The significance of the settling of blood into dependent and soft tissues as evidence for death by throttling and choking (author's transl)].

14 fresh cadavers of adult persons were placed with the head or body tilted in atypical positions 3 to 65 hours after death. The persons concerned were neither asphyxiated nor had they suffered cranial trauma. Hypostasis in the head and neck occurred more rapidly and intensively the deeper the cranial parts of the body were placed. In the simulated cadaver positions, artificial ecchymoses were observed in only a few places, mainly in the eyelids, the conjunctiva, the galea and the temporal muscles except when the head was vertically downwards. Just as with the postmortem haematomas, the hypostatic settling to the plane of the heart was decisive.

Autopsy↗
PubMedDate not supplied

The effect of amygdalectomy on orienting and classical conditioning in monkeys.

The basic findings of these two studies are as follows: a failure of orientating and conditioning of viscero-autonomic responses, but essentially normal orienting and conditioning of a temporal muscle response in amygdalectomized animals. Small procedural differences exist between the two studies,and a possible order effect exists as a result of the use of the same subjects consecutively. However, we fell that the difference between the responses of the viscero-autonomic system and the skeletal system would still be found were all of the measures gathered simultaneously in an optimal conditioning situation. The definitive study--simultaneous viscero-autonomic and skeletal (behavioral) recording--remains to be done. Trial-by-trial analysis of the correlations or lack of correlations between these responses in such a study should be highly informative. These two studies offer substantial information relevant to the original questions. When behavior is modified by simple repetition of experience the effect of amygdalectomy is restricted to the viscero-autonomic components of orienting and classical conditioning, not to the entire spectrum of responses. The issue raised, therefore, is the significance of the viscero-autonomic components of orienting and classical conditioning. The suggestion has been proposed (Pribram, 1969) that these components serve as mechanisms of internal rehearsal necessary to the registration (as novel or familiar) of the orienting and conditioning experience. This proposal requires further testing.

Amygdala↗
PubMed1999

Proton beam therapy (PT) in the management of CNS tumors in childhood.

At the Centre de Protontherapie d'Orsay, nine children with intra-cranial malignancies were treated between July 1994 and January 1998. Immediate and late tolerances were excellent in all cases (follow-up 2 to 50 months). Two patients recurred locally (marginal failures), seven are alive and doing well. At Loma Linda, 28 children were treated between 1991 and 1994, 16 for a benign tumor of the brain and twelve for a malignant one. With a follow-up of seven to 49 months, three patients died (grade 2 to 4 gliomas), one is living with a persistent disease. Four children had treatment-related toxicity (one cataract, two hormonal failures and two seizures). The other children are doing well. At MGH Boston, 18 children with skull base-cervical spine chordomas have been reported. At five years, actuarial survival and disease-free survival have been 68 and 63%, respectively. Children with cervical sites had a worse prognosis (p = 0.008). Four children had radiation-related morbidity: two pituitary failures, one temporal lobe necrosis, one temporal muscle fibrosis. In this experience, such rare tumors seemed to behave in children like in adults.

Adolescent↗
PubMed1998

Jaw-opening reflex after CO2 laser stimulation of the perioral region in man.

CO2 laser pulses selectively excite A-delta and C mechano-thermal nociceptors in the superficial layers of the skin. To study the jaw-opening reflex elicited by a purely nociceptive input, we delivered laser pulses to the perioral region in 15 subjects. Sensory threshold was very low (9 mJ/mm2). High-intensity noxious laser pulses (more than 4 x sensory threshold) evoked a single phase of electromyogram suppression (laser silent period, LSP) at an onset latency of 70 ms in the contracted masseter and temporal muscles, bilaterally. Even maximum-intensity laser pulses failed to activate the suprahyoid muscles. The recovery curves to paired laser stimuli showed that at short interstimulus intervals the test LSP was strongly suppressed. At about 380 ms it recovered to 50%, i.e. its recovery curve resembled that of the masseter late silent period after electrical mental nerve stimulation (SP2). In experiments studying the interaction with heterotopic stimuli and non-nociceptive responses, chin-taps or electrical shocks delivered to the supraorbital, infraorbital or mental nerves before laser stimulation strongly suppressed the LSP. A preceding perioral laser pulse strongly suppressed the masseter SP evoked by supraorbital stimulation and the SP2 evoked by mental stimulation, but left SPI unaffected. We conclude that the perioral A-delta fibre input elicits a jaw-opening reflex simply by inhibiting the jaw-closers. The LSP response is mediated by a multisynaptic chain of brainstem interneurons and shares with the masseter SP2 part of the central circuit in the ponto-medullary region. We also propose that a common centre processes the various inputs for jaw opening.

Adult↗
PubMed1999

Imaging of calvarial eosinophil granuloma.

We reviewed the imaging of four pathologically proven calvarial eosinophil granulomas. The diameter of the lesions ranged from 13 to 40 mm; three were biconvex, but the other had a collar-stud appearance. Two lesions were in the frontal and two in the parietal bone. On bone-window CT, a bevelled edge was seen in three cases and button sequestration in one, but no sclerotic rim was shown. Although one lesion had a low-density area, the lesions were slightly denser than grey matter. They were isointense with grey or white matter on T1-weighted MRI and gave heterogeneous high signal on proton-density and T2-weighted images. All enhanced markedly, with a less strongly enhancing portion within them. A tail of dural enhancement and reactive change in the overlying galea or temporal muscle were seen in all cases.

Bone Diseases↗
PubMed2003

A cadaveric study of a combined trans-mandibular and trans-zygomatic approach to the infratemporal fossa.

The infratemporal fossa (ITF) is a deep retromaxillary space corresponding to the inferior aspect of the middle cranial fossa. There are numerous surgical approaches, indicating the difficulty of access, accentuated by the communications with the neighboring regions. The aim of this anatomical study was the optimization and photographic demonstration of the pre-auricular infra-temporal trans-zygomatic approach combined with a trans-mandibular approach allowing access to the different regions of the ITF. Six human heads preserved in formalin were dissected under the operating microscope (magnification between x6 and x4). Intra-arterial injection of colored silicone had been done in advance. A plastinated hemi-head was conserved as a teaching and training specimen using the S10 silicone technique. After a pre-auricular temporo-cervical incision, skin flaps, the superficial temporalis fascia and the temporal fascia were elevated. The facial nerve and its branches were preserved and the temporal and zygomatic branches were protected by the superficial temporalis fascia. The division of the temporal muscle and osteotomy of the zygomatic arch opened the superior part of the ITF. Osteotomy of the mandibular ramus preserving the division of the mandibular nerve opened the inferior part of the ITF. This was thus perfectly exposed and access was not impeded by the trunk of the facial nerve and its branches. The place of this complex approach is discussed among the principal exocranial surgical approaches to the ITF.

Cadaver↗
PubMed2000

Recurrence of non-Hodgkin's lymphoma isolated to the right masticator and left psoas muscles.

We present the clinical and magnetic resonance imaging findings of a patient who, following treatment for pancreatic non-Hodgkin's lymphoma (NHL), relapsed with apparently isolated involvement of the right masticator space and left psoas muscles. Non-Hodgkin's lymphoma arising from the masticator space muscles is very rare. In addition, simultaneous lymphomatous involvement of multiple discrete skeletal muscle sites, in the absence of disease elsewhere, has previously only been reported in the limb or limb girdle muscles. Lymphoma should be considered as a cause of isolated enlarged skeletal muscles, even when involving such distant sites.

Female↗
PubMed1997

Combined revascularization surgery for childhood moyamoya disease: STA-MCA and encephalo-duro-arterio-myo-synangiosis.

We present surgical techniques for optimal revascularization in childhood moyamoya disease. During the past 10 years we performed revascularization surgery for childhood moyamoya disease using direct revascularization with superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and indirect revascularization of encephalo-duro-arterio-myo-synangiosis (EDAMS) 43 times. Points of this surgery are as follows: (1) craniotomy and dural opening for the most extensive possible exposure of the brain surface, (2) protective manipulation of the STA, temporal muscle and middle meningeal artery, (3) STA-MCA anastomosis to the frontal branch of the MCA to improve cerebral circulation of the frontal lobe using a small branch of the STA, and (4) a small opening in the arachnoid membrane and watertight closure.

Brain Ischemia↗
PubMed2002

Cranioplasty with individual carbon fibre reinforced polymere (CFRP) medical grade implants based on CAD/CAM technique.

BACKGROUND: The authors present a new method for the reconstruction of large or complex-formed cranial bone defects using prefabricated, computer-generated, individual CFRP (carbon fibre reinforced plastics) medical grade implants. METHOD: CFRP is a composite material containing carbon fibres embedded in an epoxy resin matrix. It is radiolucent, heat-resistant, extremely strong and light (its weight is 20% that of steel), has a modulus of elasticity close to that of bone, and an established biocompatibility. The utilisation of a CAD/CAM (computer aided design/computer aided manufacture) technique based on digitised computed tomography (CT) data, with stereolithographic modelling as intermediate step, enabled the production of individual, prefabricated CFRP medical grade implants with an arithmetical maximum aberration in extension of less than +/-0.25 mm. Between 1995 and February 2002, 29 patients (15 men and 14 women; mean age, 39.9 years; range, 16 to 67 years) underwent cranioplasty with CFRP medical grade implants at the neurosurgical department of the University of Vienna. Twenty-four patients were repaired secondarily (delayed cranioplasty) while 5 were repaired immediately following craniectomy (single stage cranioplasty). All cases were assessed for the accuracy of the intra-operative fit of the implant, restoration of the natural skull contour and aesthetics and adverse symptoms. FINDINGS: The intra-operative fit was excellent in 93.1% and good in 6.9% of the implants. In two cases minor adjustments of the bony margin of the defect were required. The operating time for insertion ranged from 16 to 38 minutes, median 21 minutes. Postoperatively, 86.2% of the patients graded the restoration of their natural skull shape and symmetry as excellent while 13.8% termed it good. In one patient a non-space occupying subdural hygroma was found at the follow-up, but required no intervention. Two patients experienced atrophy of the frontal portion of the temporal muscle while one patient had a transient palsy of the frontal branch of the facial nerve. Over the mean follow-up period of 3.3 years (range, 0.08 to 6.8 years), there were no adverse reactions and no plate had to be removed. INTERPRETATION: Individual, prefabricated CFRP medical grade implants may be considered as an alternative to conventionally utilised materials for cranioplasty, in particular in the challenging group of patients with extensive cranial defects or more complex-formed defects of the fronto-orbital or temporo-zygomatic region, guaranteeing short operating times and excellent functional and aesthetic results, which justifies the expense of their production.

Adolescent↗
PubMed1984

Masticatory movements and EMG activity following electrolytic lesions of the trigeminal motor nucleus in growing guinea pigs.

Unilateral electrolytic lesions were produced in the left trigeminal motor nucleus (TMN) of six guinea pigs at 49 days of age. Masticatory mandibular movement and EMG data were collected prior to lesioning and at 4 and 12 days postlesion. After the animals were killed 60 days postlesion, dissection and maceration revealed muscular atrophy and craniofacial asymmetries on the lesion side. Analyses of prelesion and postlesion mandibular movement and EMG data indicated significant (p less than 0.05; p less than 0.01) changes in chew cycle durations, dimensions, and EMG activity patterns. Shifts in EMG durations of working- and balancing-side muscles were strongly related to most of the observed skeletal asymmetries. Data indicated that muscular paresis and altered neuromuscular activity can effect skeletal changes in the mammalian craniofacial complex; total muscular paralysis is not a prerequisite for profound morphologic changes. Altered manifestation of masticatory central pattern generators within the central nervous system may also account for variations in craniofacial form and function.

Animals↗
PubMed1984

Growth and allometry in primate masticatory muscles.

A study of the dry weight of primate and non-primate masticatory musculature permitted possible allometric and ontogenetic influences on this musculature to be explored. Using weight as an indicator of adult body size, all of the masticatory muscles examined (anterior temporalis, posterior temporalis, masseter, medial pterygoid, lateral pterygoid, digastrics, and total adductor mass) are isometric. This is true even when prosimians and non-primates are removed from consideration, leaving only adult anthropoid primates. Thus, size-related changes do not affect the masticatory musculature of anthropoids differently from the musculature of examined prosimians and non-primates. However, other measures of body size (skull length, head and body length) reveal a different picture. Yet, irrespective of the indicator of body size chosen, the allometric properties of the masticatory muscles appear similar and the fluctuations of the various muscle indices therefore reflect functional changes, and are not caused by allometry. Exudate-eating and frugivory are discussed in relation to body size and the development of the mandibular depressor muscles. The logs of the masticatory muscles do not show a significant correlation with age, except when species are followed across age grades. For the five anthropoid species for which this is possible, the medial and lateral pterygoid and digastric muscles are still not correlated with age. When all examined species are considered, some muscle ratios correlate significantly with age. Following anthropoid species across age grades singles out an early surge in growth of the medial pterygoid muscle over the masseter muscle, a situation which was apparent also in the general age correlation.

Age Factors↗