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Biomedical subjects

B H Grayson

Publications and source records attributed to B H Grayson.

At least 37 records · Page 2Linked to original sources
PubMed1997

Vector of device placement and trajectory of mandibular distraction.

The role of preoperative planning, the geometric changes, and the long-term effects of mandibular distraction have not been previously reported. This study included 10 patients who underwent unilateral (5 patients) or bilateral (5 patients) mandibular distraction. Preoperative, postdistraction, and yearly radiographs (panoramic, posteroanterior, and lateral cephalograms) were reviewed. Postdistraction follow-up ranged from 12 to 70 months. Postdistraction, the mandibles showed evidence of anticipated growth without relapse. This growth rate was variable and dependent on the genetic program of the native bone. Previously reported improvement in temporomandibular joint morphology was maintained in the long term. The resulting shape of the neomandible was most influenced by the vector of placement of the distraction device. When placed vertically, ramal elongation was observed. When placed horizontally, anterior projection of the mandibular body occurred. When placed obliquely, ramal and body elongation occurred with preservation of the gonial angle. After 2 to 5 years of follow-up, continued growth of the neomandible was observed.

Cephalometry↗
PubMed1997

A CT scan technique for quantitative volumetric assessment of the mandible after distraction osteogenesis.

Distraction osteogenesis has become an accepted method of treatment for patients requiring reconstruction of hypoplastic mandibles. We present a quantitative analysis of volumetric changes after distraction osteogenesis in a series of 10 patients. Group I (n = 5 patients, 3 unilateral craniofacial microsomia, 1 Goldenhaar syndrome, and 1 bilateral craniofacial microsomia) underwent unilateral distraction of the mandible. Group II (n = 5 patients, 1 Nager syndrome, 1 bilateral craniofacial microsomia, 1 developmental micrognathia, and 2 Treacher Collins syndrome) underwent bilateral distraction of the mandible. Predistraction and postdistraction axial and three-dimensional computed tomographic (CT) scans were digitized and transferred to a computer for analysis with image-processing software to determine the changes in volume of the mandible and bony regenerate. The CT-derived volume method was validated by scanning three dry cadaver mandible specimens and comparing the volume data with those derived from a water-displacement method. The difference between the two methods was less than 5 percent. The mean distracted length, as recorded from the calibrated device, was 22.6 mm in the 10 patients. In the unilateral distraction group, the mean increase in hemimandibular bone volume was 2.8 cc, with a mean percentage increase of 27 percent in the distracted hemimandible. In the bilaterally distracted patients, the mean increase in total mandibular volume was 7.9 cc, with a mean percentage increase in bone volume of 25 percent. This study represents the first attempt to quantify the increase in bone volume resulting from distraction osteogenesis. Quantitative volumetric analysis of CT scans is an accurate method to measure the amount of bone regenerate in patients undergoing distraction osteogenesis of the mandible or the extremities. The concept and utility of quantifying the volumetric changes in bone following distraction osteogenesis may become more important as multiplanar devices are developed and used in other areas of the craniofacial skeleton.

Adolescent↗
PubMed1997

Gingivoperiosteoplasty and midfacial growth.

The objective of this study was to report the effect of gingivoperiosteoplasty on growth of the midfacial skeleton 6 years following primary surgical repair. Patients with complete unilateral cleft lip and palate who underwent primary cleft lip and nose repair with and without gingivoperiosteoplasty (GPP) were retrospectively compared by means of a lateral cephalogram. Mean age at the time of evaluation was 5.7 years. All patients were treated at the Institute of Reconstructive Plastic Surgery, New York University Medical Center. All surgery and presurgical orthopedics was performed by the same surgeon and the same orthodontist. Twenty-five consecutively treated patients who presented with complete unilateral clefts of the primary and secondary palate were included in the study. Of these, 20 patients were available for 6-year follow-up cephalometric documentation and review. All patients received preoperative orthopedics with passive molding appliances, followed by repair of the lip, alveolus, and nose in a single stage at the age of 3 months. The repair was performed using the rotation/advancement technique. The difference between the two groups was whether or not gingivoperiosteoplasty was performed. The reason for not performing gingivoperiosteoplasty was incomplete approximation of the alveolar segments usually due to a late start in beginning therapy. Lateral cephalograms (68.5 months post primary surgery) were obtained and traced. Cranial base (S-N), maxilla (ANS-PNS), and mandible (Go-Pg) were digitized for shape coordinate analysis. No significant difference in the mean position of ANS-PNS was found between groups (with or without gingivoperiosteoplasty). There was, however, a significant difference in the variance of position for the points ANS-PNS between the groups (p < .002). We were unable to observe any difference (anteroposterior or supero-inferior) in the average position of the hard palate (ANS-PNS) between groups. We conclude that gingivoperiosteoplasty results in a more uniform position of the hard palate (ANS-PNS) relative to patients that did not receive gingivoperiosteoplasty. We were unable to demonstrate any clear impairment of maxillary growth in the patients treated with gingivoperiosteoplasty when compared to patients treated without gingivoperiosteoplasty.

Alveoloplasty↗
PubMed1995

Midface distraction advancement in the canine without osteotomies.

Midface hypoplasia, often associated with exorbitism and malocclusion, has been traditionally corrected by using Le Fort advancement osteotomies through wide surgical exposure. These procedures suffer the disadvantages of hemorrhage, unpredictable bone graft resorption, the need for retained hardware, and bone graft donor-site morbidity. We present an investigation of midface distraction in the canine without osteotomies. Five canines were the subjects of this study and were divided into two groups. At the time of placement of the lengthening devices, Group 1 animals were 10 weeks of age and Group 2 animals were 5 years of age. Under general anesthesia, four modified Hoffman bone distractors were mounted on 2-mm half pins placed individually across the nasofrontal and the zygomaticotemporal sutures on each side of the craniofacial skeleton. Distraction of all devices was begun on postoperative day 1 at the rate of 0.5 mm/day for 4 days and then 1.0 mm/day for 28 days, after which interval the devices were removed. The dogs were serially monitored and examined for 3 months. One dog in the first group served as a sham control. The results were assessed by standardized cephalograms, and craniofacial computed tomographic scans with three-dimensional reconstruction performed before device placement as well as after removal of the device. In one Group 1 animal, computed tomographic scanning was performed every 2 to 4 weeks for 3 months. Gross examination of the Group 1 animals demonstrated the development of enophthalmos, dolichocephaly, and a class II malocclusion-overbite.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

Effect of mandibular distraction on the temporomandibular joint: Part 1, Canine study.

The effect of osteodistraction on the temporomandibular joint was evaluated in a canine model. Eleven mongrel dogs were used in the study. An intraoral expansion device was placed after an osteotomy was made at the angle of the mandible via an intraoral approach. The mandibles were expanded either fully to 20 mm or partially to 10 mm. After expansion, nine animals were immediately killed; the remaining two were maintained in fixation for an additional 10 weeks. Cephalometric radiographs and computed tomographic scans obtained preoperatively and before killing were evaluated. No gross temporomandibular joint deformation or bodily movement was noted in the expanded or contralateral, unexpanded side. The temporomandibular joints were harvested en bloc for gross and microscopic evaluation. Flattening of the posterior aspect of the expanded condylar head was noted, with thinning of the condylar cartilage. New bone deposition was noted, which was evident as anterior lipping. Condyles maintained in 10 weeks fixation showed reparative changes. No evidence of avascular necrosis, microfracture, or cystic degeneration was noted. This study indicates that the force of distraction can induce bony changes in the temporomandibular joint and that these effects are minimal and reversible.

Adaptation, Physiological↗
PubMed1995

Effect of mandibular distraction on the temporomandibular joint: Part 2, Clinical study.

Mandibular lengthening by gradual distraction has been gaining popularity. However, the effect of osteodistraction on the temporomandibular joint has been evaluated in patients with craniofacial anomalies who underwent mandibular distraction. Five patients had unilateral expansion and five had bilateral expansion. The mandibles were expanded 1 mm per day until the pogonion was in the midline. Preoperative, immediate, 6-month, and 12-month panoramic and cephalometric radiographs were evaluated. In unilaterally expanded mandibles, the ipsilateral condyle increased in size and volume, became more upright, and was oriented in a more normal vertical axis. The contralateral unexpanded condyle did not show deformational changes. In those mandibles that were bilaterally expanded, both condyles increased in size and volume and became more symmetrical and upright. Osteodistraction appears to affect bone in both local and distant sites. The expanded condyles were stimulated to ensure a more nearly normal shape, size, and configuration.

Adaptation, Physiological↗
PubMed1995

Twenty-year experience with early surgery for craniosynostosis: I. Isolated craniofacial synostosis--results and unsolved problems.

Early surgery for isolated craniosynostosis is designed to improve morphology, to prevent functional disturbances, and equally important, to enhance the psychosocial development of the child. As the first of a two-part series, 104 patients with isolated craniofacial synostosis were retrospectively analyzed. Diagnoses included bilateral coronal (10), unilateral coronal (57), metopic (29), and sagittal synostosis (8). All patients underwent primary fronto-orbital advancement-calvarial vault remodeling procedures at less than 18 months of age (mean 8.1 months). Thirteen percent of patients (14) required a secondary cranial vault operation (mean age 22.6 months) to address residual deficits in craniofacial form. Perioperative complications were minimal (5.0 percent), and there was no mortality. Average length of postoperative follow-up was 46.0 months. By the classification of Whitaker et al., which assesses surgical results, 87.5 percent of patients were considered to have at least satisfactory craniofacial form (category I-II) at latest evaluation. Overall rates of hydrocephalus, shunt placement, and seizures (3.8, 1.0, and 2.9 percent, respectively) were low. Among the isolated craniosynostoses, unilateral coronal synostosis/plagiocephaly poses the most complex problems, including vertical orbital dystopia, nasal tip deviation, and residual craniofacial asymmetry; there is also a wide spectrum of findings and growth patterns in this subgroup.

Craniofacial Dysostosis↗
PubMed1995

Introduction of an intraoral bone-lengthening device.

It has been demonstrated that distraction osteogenesis is an effective clinical tool with applications for the entire human skeleton. Therapeutic exploitation in the correction of the asymmetrical and hypoplastic mandible has been reported previously. However, the main criticism of this technique has been the residual cutaneous scars resulting from the surgical incision and the path of the expansion device. In order to obviate the need for skin incisions, we have developed and demonstrated the feasibility of a miniaturized mandibular bone lengthener that is suitable for intraoral placement. Ten growing mongrel dogs were studied. Under general anesthesia, a buccal mucosal incision was made along the oblique line, and the body and ramus of the mandible were exposed in a supraperiosteal plane. Two 2.0-mm half-pins were placed percutaneously in the area of the angle of the mandible, and two other pins were placed 3.5 cm anteriorly. The clamps of the lengthening device were then attached to the half-pins in an intraoral position. An osteotomy was made by connecting percutaneously made drill holes between the clamps in a line positioned posterior to the third molar. The mucosa was closed loosely over the device. Distraction was commenced on the eighth postoperative day. The results were assessed with pre- and post-lengthening photographs, cephalograms, and CT scans with three-dimensional reconstruction. All animals demonstrated a contralateral cross-bite. The newly developed bone also was examined histologically. The intraoral method of mandibular lengthening offers the same advantages of extraoral lengthening but without the need for a cutaneous incision and resulting scar.

Animals↗
PubMed1995

Twenty-year experience with early surgery for craniosynostosis: II. The craniofacial synostosis syndromes and pansynostosis--results and unsolved problems.

As the second of a two-part series, 76 patients with pansynostosis and craniofacial synostosis syndromes were retrospectively analyzed. Diagnoses included pansynostosis (7), craniofrontonasal dysplasia (8), and Apert (24), Crouzon (15), and Pfeiffer (15) syndromes. All patients underwent primary fronto-orbital advancement-calvarial vault remodeling procedures at less than 18 months of age (mean 6.1 months). Twenty-eight patients (36.8 percent) required a secondary cranial vault operation (mean age 28.4 months). Additionally, a major tertiary procedure was necessary in 5 patients to deal with persistent unacceptable craniofacial form. To address the associated finding of midface hypoplasia, 64.8 percent (n = 35) of patients underwent Le Fort III midface advancement or had that procedure recommended for them. The remainder were awaiting appropriate age for this reconstruction. The more extensive pathologic involvement of the pansynostosis and craniofacial syndrome group is illustrated. As compared with the isolated craniofacial synostosis group previously reported, the incidence of major secondary procedures (36.8 versus 13.5 percent), perioperative complications (11.3 versus 5.0 percent), follow-up complications (44.7 versus 7.7 percent), hydrocephalus (42.1 versus 3.9 percent), shunt placement (22.4 versus 1.0 percent), and seizures (11.8 versus 2.9 percent) was significantly increased. Complex problems including those of increased intracranial pressure, airway obstruction, and recurrent turricephaly or cranial vault maldevelopment are repeatedly encountered. In addition, that early fronto-orbital advancement-cranial vault remodeling failed to promote midface development and hypoplasia of this region is almost a consistent finding in the craniofacial syndromic group. The average length of postoperative follow-up was 6 years. According to the classification of Whitaker et al., which assesses surgical results, 73.7 percent of patients were considered to have at least satisfactory craniofacial form (category I-II) at latest evaluation. An algorithmic approach to the treatment of all patients with craniosynostosis is presented utilizing early surgical intervention as the key element.

Acrocephalosyndactylia↗
PubMed1992

Lengthening the human mandible by gradual distraction.

Lengthening of the mandible by gradual distraction was performed on four young patients (average age 78 months). The amount of mandibular bone lengthening ranged from 18 to 24 mm; one patient with Nager's syndrome underwent bilateral mandibular expansion. Following the period of expansion, the patients were maintained in external fixation for an average of 9 weeks to allow ossification. The patients were followed for a minimum of 11 months to a maximum of 20 months with clinical and dental examinations as well as photographic and radiographic documentation. The technique holds promise for early reconstruction of craniofacial skeletal defects without the need for bone grafts, blood transfusion, or intermaxillary fixation.

Bone Lengthening↗
PubMed1990

The Le Fort III advancement osteotomy in the child under 7 years of age.

This is a longitudinal study of 12 patients with craniofacial synostosis syndromes (Crouzon's, Apert's, Pfeiffer's) who underwent Le Fort III advancement under the age of 7 years (average age 5.1 years, range 4.0 to 6.7 years). The average follow-up was 5.0 years and included clinical, dental, and cephalometric examinations according to a prescribed protocol. The study demonstrated that the procedure could be safely performed in the younger child with an acceptable level of morbidity. There was a remarkable degree of postoperative stability of the maxillary segment. However, although vertical (inferior) growth or movement of the midfacial segment was demonstrated, there was minimal, if any, anterior or horizontal growth. Any occlusal disharmony developing during the period of follow-up could be attributed to anticipated mandibular development and could be corrected by orthognathic surgery. The roles of surgical overcorrection and anterior-pull headgear therapy after release of intermaxillary fixation are also discussed. The Le Fort III osteotomy is justifiably indicated during early childhood for psychological and physiologic reasons.

Acrocephalosyndactylia↗
PubMed1989

Cephalometric analysis for the surgeon.

A protocol for cephalometric analysis is presented to enable the clinician to evaluate the craniofacial skeleton for surgery. Cephalometric tracing and analysis are described and applied to a clinical case. The three-dimensional cephalometric method and analysis are discussed for application in planning the correction of craniofacial asymmetry.

Adult↗
PubMed1987

Mean tensor cephalometric analysis of a patient population with clefts of the palate and lip.

This study was designed to elucidate the net "effect" of primary and secondary palatal clefts on the craniofacial skeleton as viewed in the lateral cephalogram. A tensor cephalometric analysis is reported for 144 patients with cleft lip, cleft palate, or both. The study involves 13 lateral landmarks located in the patients' cephalograms and in the Michigan normative means. The net deformity (total sample) is a reduction of size in all directions, but primarily in the horizontal dimension (ANS-PNS) at the palatal level. Lower face height is affected less than upper face height. The bilateral group shows a considerably greater amount of "net" deformity in the cranial base and reduction in mandibular body length. The effect of cleft of the secondary palate alone is horizontal. The effect of an additional primary cleft is aligned instead vertically in the maxilla and intensifies the reduction of cranial base depth. These findings concur with the literature that attributes these syndromes to different mechanisms with different modes of inheritance.

Adolescent↗
PubMed1986

The mandible in mandibulofacial dysostosis: a cephalometric study.

The lower border of the mandible in mandibulofacial dysostosis is characteristic of the syndrome. Evaluation of the cephalograms by means of the medial axis analysis and inflectional tangents captures the shape deformity. Morphometric data from lateral cephalograms on seven patients, ages 3 through 20 years, are reported: a total of 22 observations on three males and four females. These forms were compared to normal mandibular forms from the University of Michigan University School Study. The curvature of the gonial angle in the study population is not distinguishable from the normal curvature. Relative to this apparently normal region, there is a marked downward displacement of the symphysis that results in the curvature typical of the lower mandibular border in this syndrome. These findings are not consistent with earlier reports.

Adolescent↗
PubMed1985

Basilar multiplane cephalometric analysis.

This article presents a method of cephalometric tracing and analysis using the basilar view cephalogram and discusses its role in diagnosis and treatment planning. Landmarks and structures found in each of three separate basilar planes are defined and instructions for tracings are presented. The analysis is applied to the study of orbital hypertelorism, craniofacial synostosis, and hemicraniofacial microsomia. The multiplane tracing technique is demonstrated to provide a three-dimensional concept of deformities in the craniofacial skeleton. A method to determine an anteroposterior midline construct from structures in the cranial base is described. As is practiced with the lateral cephalogram, presurgical tracings of the basilar film may be manipulated to simulate the skeletal changes anticipated in surgery.

Cephalometry↗