Biomedical subjects
Publications and source records attributed to R B MacIntosh.
A case is reported of a young woman who, within a 2-year period, was diagnosed with an osteoblastoma at the apex of a maxillary molar and with a plexiform unicystic ameloblastoma in the posterior mandible. Previous cases of osteoblastoma occurring in the jaws are reviewed.
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Image corrected cephalometric analysis (ICCA) is a method for eliminating serial image parallax error. In a radiographic survey, image parallax is an inherent and random property of the two-dimensional image of the subject. Radiographs of the same subject taken at different times will be different in image parallax. This difference, parallax error, is routinely displayed between serial radiographic studies. Parallax error discourages the use of conventional serial cephalometric surveys for tracking and studying changes in discrete craniofacial structures lying outside the midsagittal plane, unilaterally disposed, or changing without bilateral symmetry. Anatomic outlines or discrete points of such structures would routinely display measurement perturbations caused by image parallax differences between surveys. The ICCA method eliminates this problem. Therefore, accurate serial measurements of bone marker point displacements are made possible with two-dimensional reconstructions of points lying in three-dimensional space. The method of ICCA was tested for accuracy by using zero time serial cephalometric surveys of five subjects. Mean implant error of 0.12 mm (SD = 0.1) was found between predicted (ICCA) and actual measured implant movement caused by the image parallax error. After applying this method, bone marker movements are unlikely to be caused by parallax error between conventional serial cephalometric studies. Furthermore, displacement growth can be related to the relocation of composite growth outlines and midline anatomic landmarks. One plagiocephaly case and one hemifacial microsomia case were used to demonstrate ICCA for growth and treatment effect documentation.
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Malignant fibrous histiocytoma of the mandible has appeared frequently enough in the world literature in recent years to assume a legitimate place in the differential diagnosis of neoplastic masses of the lower jaw. This article reports a pertinent case and tabulates and correlates the findings of all cases reported thus far. The report also explores the contribution of immunohistochemistry to proper diagnosis and emphasizes the advantages of a cojoint effort between surgeon and pathologist at the time of initial patient evaluation. The case reported also demonstrates the poor prognostic characteristics of this lesion and the uncertainty as to proper mode of treatment.
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Patients whose facial esthetics are not severely compromised but who need surgical intervention for the correction of a dentoskeletal problem can be treated by repositioning of the whole mandibular alveolar segment in the direction needed to allow for such correction. The challenge to achieve efficient and relatively stable results with the use of combined orthodontic and surgical methods has been met by the use of various surgical techniques. The lower total alveolar osteotomy is another viable surgical technique that could be considered when treatment is being planned in an orthognathic surgical case. Its indications, contraindications, advantages, and disadvantages are described, and cases are reported to exemplify problems that can be corrected with this approach.
This report surveys the experience in 236 patients operated on by the author, of whom 155 provided records complete enough to provide information on all the elements of postoperative evaluation. Patients were evaluated at a minimum of 2 years after surgery. The patients had an average age of 23 years, and were predominantly female in a ratio of more than 4:1. No intraoperative or postoperative physiologically threatening problems as elsewhere described in the literature, such as profound blood loss, airway obstruction, or gross loss of bone substance, were encountered. An immediate postoperative paraesthesia incidence of almost 85% was observed, which diminished to 9% 1 year postoperatively. The prolonged paraesthesia were most common in patients over 40 years of age; similarly, healing was prolonged in patients over 40, prompting the author's recommendation that 8 weeks intermaxillary fixation rather than 6 be employed in these patients. The overall relapse rate was approximately 30%; this was clinically significant in approximately 12% of patients, and required reoperation in 4 patients. Relapse was most marked in apertognathic patients, demonstrating, in the author's opinion, that the sagittal ramus osteotomy should not be used, in general, in open-bite cases. The particulars of the technique and the author's views on regression are presented.
Surgical eradication of carcinoma of the lower lip is generally a curative maneuver. Concomitant reconstruction at this site is almost always necessary, however, and difficulties in these efforts often arise. Postoperative esthetic problems usually result when more than 30% of the lip has been removed; the most common problems are vertical scar retraction along the mucosal surface, unacceptable distortion of the commissure or overall asymmetry of the oral aperture, or both, and significantly disturbed lip motor function. During the past decade, the surgical procedure described has allowed excision of 40% of the lip and provided vertical support of the reconstructed lip and an ultimate facial appearance superior to that of other techniques.
Autogenous costochondral grafts have found application in 26 variegated cases of congenital dysplasia, ankylosis, neoplastic disease, osteoarthritis, and post-traumatic dysfunction. The authors' experience with the grafting procedure has been generally favourable, but various difficulties have also arisen. There is a cursory discussion on the physiological superiority of rib cartilage grafts over those of other autogenous joints in reconstruction of the temporomandibular articulation.
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Explore the source record for details and available documents.