Biomedical subjects
Publications and source records attributed to D S Precious.
A modified outline of Lefort 1 osteotomy using an "inverse step" design is proposed which ensures simple and effective down-fracture and pterygo-maxillary separation. Osteosynthesis of the mobilized fragment is facilitated due to the improved contact of bone surfaces, particularly laterally. Combined rigid and supple osteosyntheses allow some degree of post-operative adjustment.
Inadequate primary surgery, or a failure to establish muscular balance of the anterior face, causes muscular dysfunction. Muscular dysfunction has a nefarious effect on subsequent facial growth. Establishment of muscular balance, as early as possible, provides the best foundation for good esthetics.
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Cardiac asystole, bradycardia and other dysrhythmias are complications associated with surgery of the craniofacial and maxillofacial structures. These dysrhythmias have been discussed frequently in ophthalmology but less attention has been paid to this problem in the maxillofacial surgery literature. Eight patients, 6 men and 2 women, who underwent maxillofacial surgery during a 16-month period at the Victoria General Hospital, Halifax, Canada demonstrated either asystole or bradycardia. This group of patients represents 1.6% of the total number of patients treated during the 16-month period. Six patients demonstrated either asystole or bradycardia during stretching of the soft tissues associated with advancement of the maxilla after bony mobilization. Two patients had either asystole or bradycardia during manipulation of the temporalis muscle fibres during surgery to correct total bony ankylosis of the temporomandibular joint. The etiology of this relatively rare but troublesome complication is discussed.
This article presents a brief review of several principles which Delaire has shown to be important in both craniofacial growth and cranio-maxillofacial balance. In light of these events, we propose that the maxillofacial surgeon either avoids, if possible, the use of rigid fixation in functional genioplasty or that he removes the screws and plate at a later date. The specific patterns of bone apposition and resorption observed following functional genioplasty form the basis for this recommendation.
Vasodepressor syncope is the fulminant expression of the behavioral disorder "Blood-Injury Phobia". Vasodepressor syncope or the "common faint" is characterized by a diphasic autonomic hyperactivity that begins with anxiety and leads to a transient loss of consciousness. Recognition of the behavioral etiology of this disorder suggests the possibility of prevention through psychotherapy. Understanding the pathophysiology of the diphasic autonomic hyperactivity allows for rational management of the "common faint".
This article presents a simple rapid and practical method, based both on clinical and radiographic examinations, which the dentist can use to the patient's advantage in differentiating dental from skeletal malocclusion.
A case of duplication of the mental nerve in a patient with cleft lip, cleft palate, and rubella syndrome is presented. The most vulnerable period of fetal infection by rubella virus corresponds with the critical period of development of the maxilla, mandible, and corresponding orofacial structures. The significance of duplication of the mental nerve is discussed in relation to the influence that this anatomic structure has on the growth and development of the mandible. The concept of activisms to explain such anomalies is reviewed.
The appearance of results of injury to the columella, the nasal septum, and the nasal bones, in particular, has been well described. Anomalies of the maxilla and global facial balance secondary to nasomaxillary injury are less well known. Three cases involving children, aged 11, 14, and 17 years, who had suffered nasomaxillary injury at least 8 years earlier as a result of physical beating, were studied with the use of photographs and architectural craniofacial lateral cephalometric radiographic analysis. The architectural craniofacial analysis of Delaire produced a graphic representation of the resultant maxillofacial deformities rather than a description of the deformities in terms of deviation from a statistical mean. Traumatic injury to the nasomaxillary complex provides an experimental model that implicates the role of the cartilaginous nasal septum and local functional conditions in the growth of the nasomaxillary complex. The importance of the functional premaxillary skeletal unit in balanced facial growth allows better understanding of the pathophysiology of malformation of this region.
Wide subperiosteal undermining in primary surgical correction of labio-maxillary clefts not only enhances the osteogenic activity of the periosteum but in addition, if the exposure is extended from the superior limit of the ascending maxillary process and the nasal bone to the inferior orbital rim above the infra-orbital foramen and the malar eminence, good suppleness of the overlying muscles can be achieved.
This article reviews some of the complications associated with the use of a chisel to achieve separation of the pterygomaxillary region during the Lefort I osteotomy. A modification of this surgical procedure is proposed whereby no chisel is used to complete the maxillary disjunction. A series of more than 200 consecutive Lefort I osteotomies using this technique confirms the value of this modification.
A technique is presented that allows the clinician to produce a lateral skull cephalometric radiograph that is suitable for construction of the architectural and structural analysis of Delaire involving only minor alterations in existing equipment. An appropriate combination of film type screen and cassette is recommended.
The authors report a case of a 36 year old black American male, who was operated for a fracture of the mandibular angle. A second surgical procedure was necessary, because of post-operative infectious complications. An hemolytic anemia occurred which was linked to a glucose-6-phosphate dehydrogenase (G6PD) deficiency. Clinical and general aspects of the disease are discussed.
The authors report a technique of sagittal split osteotomy of the ramus, which varies from accepted techniques, and permits maintenance of integrity of the neurovascular bundle and, at the same time, good visibility of the developing split. 78 cases of this technique are reviewed.
Forty Fischer strain inbred albino rats, evenly divided by sex, were obtained at 9 days of age. The animals were weaned at 21 days and randomly divided into the four experimental groups. Two variations on dietary consistency, hard and soft diet, as well as two variations on cage environment, normal and no biting surfaces, constituted the experimental groupings. The experimental period consisted of 16 weeks during which the animals were raised under the designated conditions. At the end of the experimental period the animals were killed with carbon dioxide, and the entire mandible, and both femurs, were dissected free. Weight and volumetric analysis were carried out in a standard fashion on the cleaned specimens. Area and linear measurements were performed and analyzed with a specially designed computer program. The results showed that there was sexual dimorphism in the Fischer rat both with respect to body weight and the weight, volume, area, and linear measurements of the mandible. The effects of dietary consistency had a greater influence on mandibular ramus size and form than did those caused by alteration in cage environment. The posterior region of the mandible, in association with the heavy muscles of mastication, was affected more by dietary consistency than was the anterior region. The entire region of the mandibular ramus acted as an area of adaptation and growth. The findings of this study indicate that dietary consistency has a small but significant effect on mandibular size in specific measurements. The cage environment used in this experiment did not limit function to the extent necessary to see measurable changes in mandibular measurements.
The authors report a case of an 8 year old boy, who was operated for a giant cell reparative granuloma of the mandibular symphysis. During follow-up, two dentigerous cysts were surgically removed, in the same area. No recurrence of the GCGR was noted 5 years after removal.
The authors report the case of a nine year old girl, who was treated for a giant cell reparative granuloma of the right mandible. Surgical excision of this tumor was accomplished via a transoral approach and intentional division of the mental neurovascular bundle. Immediate gross repair of the nerve was carried out at the same operation. Complete normal sensation returned in less than eight months. The salient features of the giant cell reparative granuloma are presented, and the discussion includes description of the techniques of nerve repair.