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Concertina effect and facial aging: nonlinear aspects of youthfulness and skeletal remodeling, and why, perhaps, infants have jowls.

The effect of aging on the orbitomaxillary region is evaluated in the present study. The observation was made that infants look like aged individuals in terms of the midface soft-tissue contours of the midface. Because preliminary work has shown that the facial skeleton remodels throughout life, this observation led to the hypothesis that infants and older individuals appear similar because they have comparable skeletal dimensions, specifically in the orbitomaxillary region. The design is a retrospective analysis of three-dimensional computed tomographic scan data. Three groups of male subjects were studied: infant, ages 1 to 12 months (n = 5); youthful, ages 15 to 24 years (n = 13); and old, ages 53 to 76 years (n = 12). Orbital and zygomaticomaxillary vertical dimensions were measured in both medial and lateral planes between fixed anatomical landmarks. Results were compared by using analysis of variance, Student-Newman-Keuls, and Student's t tests. The findings show that skeletal remodeling is such that the ratio of the maxillary height to orbital height is greatest during youth; during infancy and old age, there is a short maxilla relative to a larger orbit. This finding is significant in the medial plane from orbital rim to pyriform aperture (p < 0.05). Furthermore, there is an actual decrease in vertical maxillary height in this medial plane (p < 0.01) from youth until old age, which occurs secondary to normal skeletal remodeling in the dentate individual. The combined effect of downward expansion of the orbital shelf and the upward migration of the pyriform effectively decreases the space available to support the overlying soft tissues of the midface. An accordion-like or "concertina" effect may lead to compression or restriction of the facial soft tissues over a relatively deficient bony platform. These results highlight the importance of skeletal remodeling in determining the soft-tissue contours of the aging face. The process of skeletal remodeling may also allow for a tentative definition of facial youthfulness. Infants are born with a short maxilla relative to a large orbit, and the maxillary wall is angled posteriorly. This ratio and angle change from infancy until youth, when there is a balance between the bony skeletal support and the overlying soft-tissue envelope, i.e., the skin, facial muscles, and adipose tissue. It is when skeletal remodeling continues past this point that a disharmony occurs. Because the ratio of maxilla/orbit, and the angle of the maxillary wall, in the older person reverts toward that of an infant, the attainment of youth occurs partly in a nonlinear or multimodal manner. This work is part of an emerging concept of facial aging, which we would term an integrated model of facial aging. This model allows facial aging to be viewed as a biological "system," in which there are primary and secondary factors that interact in the process of facial aging. Additional research such as this continues to suggest the importance of bony remodeling in facial aging.

Adolescent↗

Long-term effects of and physiological responses to nitrous oxide gas treatment during alcohol withdrawal: a double-blind, placebo-controlled trial.

BACKGROUND: Nitrous oxide gas (N2O) has been proposed to be effective in the treatment of the alcohol withdrawal syndrome (AWS). This has not been proved, however, in studies performed according to good clinical practice guidelines. Moreover, previous studies have not measured end tidal N2O concentrations or physiologic responses during N2O treatment. We have recently reported that in a double-blind, randomized, controlled setting, N2O was not superior to placebo in relieving AWS symptoms. In this previous study, we did not find significant differences between the treatments either in the Clinical Institute Withdrawal Assessment of Alcohol scores or in the total use of benzodiazepines (diazepam and temazepam). The aim of the present study was to characterize other effects and side effects of the N2O treatment using several objective measures and to study the possible long-term efficacy of the treatment. METHODS: A total of 105 inpatients who had AWS and were admitted to the A-Clinic detoxification center were included in the study. The subjects were randomly assigned to one of the following three treatments: (1) N2O/oxygen (from 30 to 70% in oxygen), (2) air/oxygen (30%/70%), and (3) medical (normal) air. During the single 45-min treatment period, end-tidal N2O, carbon dioxide, and oxygen concentrations were measured. The physiologic responses were studied by measuring heart rate, blood pressure, pulse oximetric saturation, frontal muscle electromyographic activity, and plethysmographic pulse amplitude. Long-term effects were studied by measuring craving with the Obsessive-Compulsive Drinking Scale; severity of dependency with Severity of Alcohol Dependence Data; and liver enzymes with aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase 3 and 6 months after the treatment. RESULTS: Patients in the N2O group demonstrated significantly higher facial muscle electromyographic activity and higher pulse amplitude than the air-treated subjects. Self-reported side effects between the gas treatments, however, did not differ between the groups. Regarding long-term effects of the treatments, there were no differences between the groups. CONCLUSIONS: Contrary to previously published data, N2O treatment did not decrease craving or liver enzymes during the 6-month follow-up. At the concentration used, N2O treatment produced signs of arousal instead of strong sedation.

Alcoholism↗

Different molecular basis for spinal muscular atrophy in South African black patients.

Spinal muscular atrophy (SMA) is an autosomal recessive disorder occurring at a rate of between 1/5,000 and 1/10,000 births in most European countries. The phenotype results from the degeneration of the anterior horn cells of the spinal cord, resulting in symmetrical muscle weakness and wasting. The disorder can be classified according to the severity of the disease and the age of onset into three major types. Two candidate SMA genes, NAIP and SMN, isolated from the 5q13 region, have been reported to be homozygously deleted in approximately 30% and >95% of SMA patients, respectively. Black SMA patients have been reported to have facial muscle weakness more commonly. This study aimed to determine the molecular basis of SMA in South African black SMA patients. The SMN gene was found to be homozygously deleted in 65.5% (19/29) of patients, significantly less frequently than in previous studies. Similarly, the NAIP gene was homozygously deleted in a smaller number, 14% (4/29) of patients; 47% (9/19) of SMN deletion patients appeared to have deletions of telomeric exon 7, but not exon 8. In at least six of these patients a gene conversion event has occurred. No detectable deletions were found in 35% (10/29) of patients. Haplotype analysis in the nondeletion patients, using six closely linked markers, provided no evidence for a founder mutation. No mutations were found in exons 3 and intron 6 through exon 8 by sequence analysis of these nondeletion patients. It is proposed that the differences in the SMA phenotype observed in black patients may in part be explained by a different molecular basis.

Black People↗

The effect of musculoskeletal facial pain on registration of maxillomandibular relationships and treatment planning: a synthesis of the literature.

STATEMENT OF PROBLEM: A significant number of patients exist who are in need of prosthodontic rehabilitation and who at the same time report musculoskeletal pain in the facial area. PURPOSE: This article, which is based on an assessment of both the past and the most recent basic science and clinical literature, evaluates the effect of musculoskeletal facial pain on two static (physiologic rest position and centric relation) and two dynamic (protrusive border and lateral border movements) maxillomandibular relationships. MATERIAL AND METHODS: To find the relevant studies addressing the association between musculoskeletal facial pain and maxillomandibular relationships, a MEDLINE search was conducted, which was complemented by a hand search in selected journals. RESULTS AND CONCLUSIONS: Musculoskeletal facial pain seems to variably affect the aforementioned positions and movements. Hence, the validity of maxillomandibular registrations in patients with existing facial pain is questioned. In those patients with facial pain who simultaneously are in need of a prosthodontic rehabilitation, clinicians should be cautious with regard to the timing of the restorative procedures.

Centric Relation↗

Bilateral acoustic neuromas.

This article reviews 12 patients with bilateral acoustic neuromas. The sex incidence was equal and the mean age at diagnosis was 26.2 years. The family history was positive in nine of the patients. Five patients have had incomplete surgical removal of acoustic neuromas on both sides. Two of them are completely deaf and the other three have severe sensorineural hearing loss in one ear and no hearing in the other ear. In five patients the tumour on one side has been operated on and the other side is being observed with at least short-term preservation of good hearing. The remaining two patients died of intra-cranial complications, one of them post-operatively. Four patients developed facial palsy immediately following surgery and one developed facial weakness 6 months after surgery. Guidelines are discussed for the care of these patients including the timing of surgery and alternative treatment options (observation, radio-surgery and chemotherapy). This is essentially a group of young individuals who have had multiple operations for bilateral acoustic tumours and associated manifestations and for whom the disease and the sequelae of treatment can be tragic.

Adolescent↗

Microsurgical treatment of intractable hemifacial spasm.

Ten patients with intractable hemifacial spasm were treated by posterior fossa exploration and microsurgical technique. These patients have been followed 1 to 5 years. The spasmodic motor disorder was related to compression of the 7th nerve or its exit zone at the brain stem by a dolichoectatic anterior inferior cerebellar artery in eight patients and to kinking and ectasia of the basilar or vertebral artery in two patients. In five patients, there were prominent arachnoidal adhesions in the cerebellopontine angle, and an arachnoid cyst was a component of the lesion in another patient. Additional conditions associated with hemifacial spasm included geniculate neuralgia, facial paresis, vertigo, hearing loss, and trigeminal neuralgia. The surgical morbidity and postoperative results are discussed.

Adult↗

Hypoglossal-facial nerve anastomosis and electromyographic feedback rehabilitation.

Electromyographic (EMG) feedback has been proposed to enhance rehabilitation following hypoglossal-facial nerve anastomosis. Sixteen of 25 patients who underwent hypoglossal-facial nerve anastomosis with and without postoperative EMG rehabilitation were videotaped for evaluation of facial movement by four observers unaware of these patients' rehabilitation therapy. Using a House Facial Nerve Grading System and intragroup comparison, a trend discernible in this preliminary study indicates a chance for better facial function with EMG feedback rehabilitation.

Adult↗

[Long-term results of surgical therapy of hemifacial spasm and blepharospasm (author's transl)].

Between 1965 and 1976, 95 patients with hemifacial spasm and blepharospasm have been operated according to the method developed by Fisch at the ENT-Clinic of the University of Zurich. 69 of the patients were followed over an interval of 1 to 12 years. 80% of the patients with hemifacial spasm and 65% of the patients with blepharospasm were free of symptoms or significantly improved. These results remained unvaried over an observation period of 6 to 12 years. The motility of the face was preserved to a very high degree in spite of extensive resection of peripheral facial nerve branches.

Blepharospasm↗

Spontaneous facial movement.

Otolaryngologists should be aware that there is a large differential diagnosis to be considered in patients presenting with spontaneous facial movement. A practical classification of the various forms of such movement is presented. Current thinking regarding the etiology and treatment of the more common conditions is reviewed.

Adult↗

[An index for paresis and defective healing--an easily applied method for objectively determining therapeutic results in facial paresis (author's transl)].

Residuals of facial paralysis consist of a great variety of cosmetic and functional anomalies which differ in quality and/or quantity. An internationally standardized evaluation of such defects is mandatory for the assessment of the results of different therapeutic procedures. In the present study, a system has been developed to record the results of facial paralysis following therapy. Such a system does not require specialized training, instrumentation or require significant time for completion. A clearly-defined "Yes-No" evaluation criteria is established which creates a high interscorer reliability. The usefulness of this scoring system was tested by three examiners on 42 patients following facial nerve surgery, with an obtained interscorer reliability of 93%.

Eyelid Diseases↗

Control of oro-facio-lingual movements by the substantia nigra pars reticulata: high-frequency electrical microstimulation and GABA microinjection findings in rats.

To provide direct evidence for substantia nigra pars reticulata (SNr) control of oro-facio-lingual muscle activity, high-frequency electrical microstimulation (mainly trains of 20, 333-Hz cathodal pulses at 40-60 microA) and GABA microinjection (1-5 microl of 10 mM GABA in saline) were carried out using a three-barreled microelectrode at the same SNr site in lightly anesthetized, chronically decorticated rats (n=39). Decortication eliminated the possibility that SNr microstimulation might activate corticofugal fibers descending in the adjoining cerebral peduncle. When the most ventral layer of the SNr was approached, high-amplitude electromyographic (EMG) activity of up to 6 mV with a distinctive waveform appeared synchronously with electrical stimuli in the anterior digastric, masseter, genioglossus, and levator labii superioris muscles. This EMG activity was evoked bilaterally, with an ipsilateral predominance. Eye movements, mostly rotation of the eyeball vertically down in the orbit, were noted. Infrequent blinking was also noted. Histologic examination localized the effector site to the middle third of the mediolateral extent of the caudal SNr corresponding to between 5.8 mm (level of the oculomotor nerve) and 6.5mm (caudal end of the SNr) caudal to bregma; and to the ventralmost peripeduncular region of the SNr corresponding to 7.7 mm to 8.0 mm beneath the cortical surface. We referred to this site as the substantia nigra pars reticulata oro-facio-lingual (SNr-ofl) region. GABA injection produced tonic EMG discharge with consistent amplitude in all of the four muscles studied. The GABA effect was negated by a preceding microinjection of the GABA-A receptor antagonist bicuculline, whereas saline control injection had no effect. Changes in amplitude of evoked EMG activity according to location of the stimulating microelectrode reflected somatotopic organization of the SNr-ofl region. This extremely localized electrical and receptor microstimulation in the SNr produced synchronized powerful contraction of jaw, tongue, and facial muscles with different neural innervation. These findings advance our understanding of the mechanisms of the SNr concerning oro-facio-lingual movements.

Animals↗