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Biomedical subjects

S A Schendel

Publications and source records attributed to S A Schendel.

At least 37 records · Page 2Linked to original sources
PubMed1991

Nasal considerations in orthognathic surgery.

The functional correction of dentofacial deformities by orthognathic surgery produces major changes in facial appearance. Facial esthetics must therefore be equally appreciated by the orthodontist and the maxillofacial surgeon. The orthodontist must perform a thorough esthetic facial evaluation along with his usual orthodontic evaluation. The treatment plan must then be based on the esthetic evaluation and knowledge of the facial changes caused by orthodontic treatment and skeletal jaw surgery. Central to facial form is the nose. This article will outline the proper functional and esthetic evaluation of the nose in relation to the face. Nasal and upper lip changes associated with maxillary procedures will also be covered in detail. In light of these two areas, proper treatment planning and sequencing will be discussed.

Adolescent↗
PubMed1991

Pathophysiology of cleft lip muscles following the initial surgical repair.

Muscle biopsy specimens taken from the upper lip and perialar area during the time of secondary lip revision and studied by histochemical techniques demonstrate persistent connective-tissue and muscle abnormalities even at a distance from the cleft margins. Some of these changes are consistent with surgically induced denervation-reinnervation of muscle groups in the surgical field. Increased amounts of connective tissue also were found, most likely secondary to the original deformity and the subsequent surgical procedures. Both these changes may be important factors in subsequent abnormal growth and development of the underlying midfacial structures. This study also demonstrated the resolution of previously noted mitochondrial abnormalities found in the primary cleft lip patient.

Adolescent↗
PubMed1990

The iliac crest cartilaginous cap.

Bone and cartilage grafts can be procured from the ilium either separately or as composite chondroosseous grafts when sufficient cartilage is present. The thickness and anatomy of this iliac cartilaginous cap was analyzed in relationship to age in 50 individuals. Histology was that of normal hyaline cartilage. The cartilage alone was more pliable with little memory when compared with auricular or septal cartilage. The cartilage/bone junction was very strong. Cartilage thickness ran from close to 1 cm at age 5 to a diminished zero at age 25.

Bone Transplantation↗
PubMed1989

Pathophysiology of cleft lip muscle.

Although attention has been focused for decades on the correction of cleft lip deformities, our knowledge about the etiology of such deformities has remained presumptive. Sixty-six muscle biopsy specimens from cleft lip infants were obtained at the time of primary closure. Histochemical stains, histographic analysis, and electron microscopy were performed. A nonneurogenic muscle atrophy was seen that varied in severity, with muscle fibers near the cleft being the most atrophic and disorganized. Muscle fibers stained with the modified Gomori trichrome technique also demonstrated "ragged red" fibers typical of a mitochondrial myopathy. Electron microscopy confirmed large accumulations of mitochondria distorting the fibrils. These mitochondria also were increased in size and densely packed with cristae. This study thus demonstrates that the muscles in cleft lip deformities are not normal. Instead, they reflect either myopathy in the facial mesenchymal mitochondrion or at least a delay in maturation. We hypothesize that some of the morphologic deformities associated with cleft lip may cause a failure of mesenchymal reinforcement of the facial processes at a critical time in development.

Cleft Lip↗
PubMed1988

Van Buchem disease: surgical treatment of the mandible.

First described in 1955, Van Buchem disease is an infrequently occurring hereditary sclerosing bone dysplasia. It is more properly called hyperostosis corticalis generalisata. The most striking feature is an unusual enlargement of the mandible with a normal dental occlusion. Skull base, spine, and pelvic bone involvement is also seen. The defect appears to be an increase in cortical bone thickness or sclerosis. The condition first appears around puberty in the autosomal recessive type and in early childhood with the autosomal dominant type. Reported here is a family with Van Buchem disease, in which surgical recontouring of the mandible was performed for one of the members. The surgery was performed by a combined intraoral/extraoral technique with good aesthetic results and minimal morbidity. A differential diagnosis and workup is also presented.

Adult↗
PubMed1987

An analysis of factors influencing stability of surgical advancement of the maxilla by the Le Fort I osteotomy.

Skeletal stability after maxillary surgical advancement was studied in 30 patients. Postoperative movement of all measured skeletal and dental points were on the average negligible. Equal stability was seen in maxillary advancement alone and with concomitant mandibular surgery. Eight cases examined individually showed larger than desired postoperative movements. In six of these cases the undesirable postoperative changes were secondary to undesirable preoperative orthodontic flaring of the incisors. The Begg orthodontic technique, because of its tendency to axially rotate teeth, was shown to produce more variability in tooth position than edgewise orthodontics. This study confirms that no preoperative flaring of the maxillary incisors should be attempted; instead, the teeth should be retracted and placed over basal bone with a normal axial inclination. Occlusal correction should then be accomplished by surgery. Suspension wires and bone grafting are sufficient to obtain skeletal stability in cases of maxillary advancement up to 11 mm. In cases where the surgery is more complex, rigid fixation is recommended.

Bone Nails↗
PubMed1986

Computed axial tomographic assessment of cranioorbital anatomy in unilateral clefts.

Anatomy of the cranioorbital region in the unoperated infant with cleft lip/palate, is not well known. In this study, computed axial tomography was performed in 7 infants with unoperated unilateral cleft lip combined with cleft palate but no recognized craniofacial syndromes, and on 5 age-matched control infants. Significant differences were found between the infants with cleft lip/palate and the normal infants. There was more plagiocephaly in the cleft group, and the flattened forehead on the involved side was associated with less facial projection. The angles of the petrous portions of the temporal bones and midsagittal plane were also significantly more obtuse in the cleft group. In the normal group the lateral orbital walls and petrous portions of the temporal bones formed a large symmetrical X. This X in the cleft groups was distorted and not readily recognizable. There were also trends indicating possible differences in the orbital and ethmoid orientations in the two groups.

Cleft Lip↗
PubMed1985

Variations of total vertical maxillary excess.

The long-face syndrome is a well-recognized entity, yet the pathogenesis of this malformation remains obscure and variations are generally not recognized. Fifty lateral cephalometric radiographs of patients who underwent vertical maxillary reductions were studied using the architectural and structural analysis of Delaire. Several subgroups of vertical maxillary excess that had not been recognized previously were identified. The most common dysmorphic type was the classically described long-face syndrome; the next most common consisted of patients who had short upper lips, normal maxillas, and long faces secondary to vertical chin excess. In all, six different variations of vertical maxillary excess were identified. Concomitantly, in the majority of cases there was associated vertical mandibular chin excess. It is suggested that these variations may have differing pathogeneses.

Adult↗
PubMed1985

Genioplasty: a physiological approach.

Genioplasty results in aesthetic and functional changes to the chin and perioral areas. A physiological approach combines osseous and soft tissue reconstruction to produce a superior result that is especially important in individuals with bilabial incompetence. In this review, facial muscle hyperfunction and vertical maxillomandibular excess are identified and their treatment outlined. The modified Michelet genioplasty, an ideal technique for vertical chin reduction and/or advancement, is described.

Adolescent↗
PubMed1983

Muscle reorientation following superior repositioning of the maxilla.

In facial reconstructive surgery the importance of the orofacial muscles on form, function, and esthetics must be recognized. Once this fact is acknowledged, these muscles may be manipulated to advantage by the surgeon; thus, undesirable effects in the perioral area following superior repositioning of the maxilla can be avoided. A V-Y advancement-closure of the horizontal maxillary vestibular incision is advocated. This successfully repositions the lip muscles in a predictable manner and maintains normal lip form pout, and amount of exposed vermilion. Alar width and unesthetic widening of the alar bases may also be controlled by the proper repositioning of the transverse nasalis muscles. The validity of these surgical procedures is supported by a statistical analysis of the lip and nasal structures in patients whose dentofacial deformities were corrected by superior repositioning of the maxilla and concomitant facial muscle reorientation.

Facial Muscles↗
PubMed1982

Superior repositioning of the maxilla during growth.

Sixteen individuals between the ages of 10 and 16 years who underwent superior surgical repositioning of the maxilla to correct vertical maxillary excess and were followed up for at least one year after surgery were evaluated. Follow-up ranged from 12 to 78 months with a mean of 36.7 months. The effects of subsequent growth on the esthetic, occlusal, and skeletal results achieved immediately following surgery were evaluated through analysis of profile esthetics, dental occlusion, and skeletal changes which occurred from the immediate postoperative period to longest follow-up examination.

Adolescent↗