Biomedical subjects

L A Whitaker

Publications and source records attributed to L A Whitaker.

At least 55 records · Page 3Linked to original sources

PubMed1990

The operative treatment of isolated craniofacial dysostosis (plagiocephaly): a comparison of the unilateral and bilateral techniques.

Both the safety and efficacy of the treatment of isolated craniofacial dysostosis (plagiocephaly) in infancy have been demonstrated. Opinions remain divided, however, as to the optimal type of procedure to be undertaken. In an attempt to answer this question, we have retrospectively evaluated a study population of 48 children operated on in infancy by either a unilateral or bilateral approach. Results of treatment at a minimal follow-up of 3 years were assessed based on preoperative and postoperative photographs and direct patient examination. Based on this retrospective comparison of the unilateral and bilateral approaches to the treatment of isolated craniofacial dysostosis, we conclude that (1) either approach as specifically outlined will give excellent results in the majority of patients, (2) there is no statistically significant difference in the results obtained by using either procedure, (3) in the majority of instances, less than ideal correction was manifested by contour irregularities evident in the temporal and/or lateral forehead region, and strict attention should be given to these areas in an attempt to further improve results, and (4) in those cases where significant protrusion is observed on the "normal side," a bilateral approach is preferable.

Bone Transplantation↗

PubMed1990

A method for repositioning the external ear.

The malposition of an otherwise normal-appearing external ear is not uncommon in certain craniofacial syndromes. This paper presents a 10-year experience of 14 patients who underwent external ear repositioning. In this technique, a posterior incision is used to mobilize surrounding soft tissues circumferentially around the external auditory canal, which then serves as an axis for anterior rotation and elevation. Elevation of up to 8 mm and rotation up to 30 degrees can be achieved. Further elevation is limited by the ensuing constriction and resistance of the external auditory canal. More rotation can be achieved with a Z-plasty transposition of an inferiorly based postauricular skin flap.

Child↗

PubMed1990

Reconstruction of late craniofacial deformities after irradiation of the head and face during childhood.

Little is known about the results of surgical management of late craniofacial abnormalities arising after irradiation of the head and face for treatment of childhood cancers. The clinical records of 10 children (4 males and 6 females) who received 4500 to 6500 rads (mean 5160 rads) of craniofacial radiation between birth and 8 years of age (mean 5 years) and who subsequently had reconstructive surgery were reviewed. Six of the 10 patients received orbital radiation, 3 received maxillary-midfacial radiation, and 1 patient underwent radiation to the frontal bone. Histologic tumor types included retinoblastoma (4), rhabdomyosarcoma (3), Ewing's sarcoma (2), and neurofibrosarcoma (1). In addition to radiation, 7 of the 10 patients underwent surgical resection or debulking of their tumors and 6 received adjuvant chemotherapy. All patients presented from 4 to 20 years after treatment (mean 10 years) with varying, but severe degrees of soft-tissue and bony hypoplasia of the irradiated territories. Onlay bone grafting with soft-tissue reconstruction by a combination of local pedicle flaps and dermal-fat grafts was initially performed in 9 patients, and an occipitoparietal bone-flap switch procedure was done in 1 patient. Late follow-up ranged from 11 months to 7.5 years (mean 34 months). A total of 8 secondary procedures were necessary in 4 of the 10 patients (40 percent). Of these 4 patients, major revisions were performed in 3 and minor adjustments in 1. In addition, 2 patients in whom secondary procedures had not been done would benefit from further reconstruction. Therapy for cancer of the head and face during childhood has profound and ongoing effects on the growth of soft tissue and bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

The effect of rigid fixation on the survival of onlay bone grafts: an experimental study.

Much attention has recently been focused on rigid fixation as a method of improving fracture healing. Whether such fixation, when applied to onlay grafting, improves graft take and volume is unknown. To examine this question, we compared survival of both endochondral and membranous grafts fixed rigidly and nonrigidly in areas of low motion (snout) and high motion (femur) in a rabbit model. Gross morphology, histologic analysis, and graft volume kinetics were evaluated. Findings demonstrate that in areas of high motion, the application of rigid fixation improves graft survival, whereas in a low-motion region, no differences in graft volume retention as a function of fixation were observed. Histologically, no differences with the method of fixation employed were seen, and similar revascularization patterns were noted. By kinetic analysis, rigid fixation appears to exert its most profound effect early in the postgraft period. Membranous bone grafts remain superior to endochondral grafts under all circumstances. From these studies, we conclude that rigid fixation is the method of choice in all circumstances where onlay bone grafts may be exposed to motion, shear, and torsional forces.

Analysis of Variance↗

PubMed1989

Growth and survival of vascularized and nonvascularized membranous bone: an experimental study.

Although nonvascularized membranous bone grafts to the craniofacial skeleton demonstrate improved survival over similar grafts of endochondral origin, the comparative fate of vascularized membranous grafts is unknown. It is also unknown whether onlay membranous bone grafts in immature animals have the ability to grow. To examine these questions, a model was developed in New Zealand white rabbits in which a segment of the zygomatic arch was transferred to the subjacent mandible as either a vascularized or nonvascularized transfer. At harvest 16 weeks later, residual graft volume and bone architecture were analyzed. Results demonstrate no improved survival for vascularized membranous grafts in adult animals (n = 7), while in the immature animals (n = 6), growth of the vascularized bone transfers was documented. We conclude that in the majority of instances in craniofacial reconstruction, nonvascularized onlay membranous grafts are to be preferred. Specific instances for the use of vascularized transfers will be discussed.

Animals↗

PubMed1989

Biological boundaries: a concept in facial skeletal restructuring.

The concept of biological boundaries is based on observations of craniofacial restructuring. It describes the body's intrinsic sense of physical surface and how this knowledge can be used to determine when to use bone grafts, segment shifts, or synthetic material.

Bone Development↗

PubMed1989

Aesthetic contouring of the facial support system.

The skeletal foundation and its attachments provide a basis for changing the basic structure of the face. Detailed preoperative evaluation and a clear understanding between the patient and surgeon of the aesthetic goals are essential prior to proceeding with surgery. Besides a knowledge of the normal aesthetic and arthropologic measurements, the surgeon must have an understanding of the range of methods available prior to proceeding with surgery. For minor alterations, contour reduction or augmentation should be considered. In the temporal fossa, augmentation with synthetic material is preferred. In the supraorbital ridge and chin autogenous tissue is generally the material of choice. An understanding of when and how to use these materials is the essence of achieving satisfactory results.

Esthetics↗

PubMed1988

Aglossia with congenital absence of the mandibular rami and other craniofacial abnormalities.

We describe a severe first branchial arch abnormality including nearly complete absence of mandible, hypoplasia of the maxilla and the zygomatic arches, and complete gingival fusion in a chromosomally normal child born to a nonconsanguineous couple who deny prenatal exposures. A tight orbicularis oris muscle caused the lips to be constantly pursed. Intraoral contents could only be defined after the fused gingiva were separated. The infant had hypoplasia of the buccal cavity with a persistent membrane separating it from the pharynx; palate structures and tongue were absent. The orbits and midface were severely hypoplastic. However, the ears were normal in shape and only slightly low in position. There was unilateral optic nerve coloboma and coronal craniosynostosis. The only noncraniofacial malformation was an atrial septal defect. Embryologically, there is severe malformation of structures arising from the cephalic neural crest cells of both the maxillary and mandibular prominences of the first branchial arch. However, the first branchial cleft region was spared.

Facial Bones↗

PubMed1988

General body growth in children with cleft palate and related disorders: age differences.

Clefts of the lip and palate, separately or in combination, are among the most frequent congenital defects seen today. Their etiology is heterogeneous and may include hormonal factors, which suggest the possibility of growth effects. Whether affected children are smaller than others has not been determined. We recently showed that growth status is associated with type of cleft. We hypothesized genetic alterations in metabolic pathways that alter prenatal growth, producing clefts; some of these alterations also alter postnatal growth. Since the levels of growth-regulating hormones change during ontogeny, we expected age differences in the degree of growth deficit seen. To test this hypothesis, we examine here the cross-sectional means and distributions of standard deviation (z) scores for height and body mass indices (BMIs) for 144 children with the diagnoses unilateral cleft lip and palate (uCLP) and isolated cleft palate (iCP). We find that alteration in growth status is associated with age group as well as sex and diagnosis.

Adolescent↗

PubMed1988

Electrical stimulation of onlay bone grafts.

An animal model was developed to determine the ability of capacitively coupled electrical fields to enhance onlay bone graft survival in the craniofacial skeleton. Fifteen male New Zealand white rabbits were divided into control and stimulated groups. Blocks of iliac bone were transplanted as onlay grafts to the mandibular rami. In all animals a capacitor apparatus was attached externally over the right mandibular ramus; however, a 5-V peak-to-peak sinusoidal signal was applied only in the stimulated group. The experimental period was 6 weeks, with a total of 30 days of constant stimulation. Graft resorption in the stimulated animals was decreased a total of 24.8 percent (p less than 0.001). There appeared to be a trend toward decreased graft resorption caused by the apparatus alone, although this was not statistically significant. The electric field alone decreased resorption by 11.5 percent (p less than 0.05). No distinguishing features were demonstrated by fluorescent vital stains or routine histology.

Animals↗

PubMed1988

Psychosocial outcome of craniofacial surgery in children.

Thirty-four children between the ages of 7 and 15 years with congenital craniofacial anomalies underwent psychosocial evaluation before and 12 to 18 months after surgery. Also evaluated were healthy children matched to the craniofacial subjects by sex, age, intelligence, and economic background. Preoperative assessment revealed the craniofacial group to have multiple but not severe psychosocial limitations. At follow-up, only a measure of social functioning still differentiated the groups, with the craniofacial subjects experiencing more negative social encounters. Comparison of initial and follow-up scores for the craniofacial group revealed a significant reduction in trait anxiety and trends toward reduction in parent-reported inhibited and hyperactive behavior. Scores on measures of extraversion and social functioning tended to be positively correlated with age for the comparison subjects only. Results suggest a modest improvement in psychological adjustment following surgery with a residual, possibly increasing, deficit in social functioning.

Adaptation, Psychological↗

PubMed1988

Orbital reconstruction in hypertelorism.

Orbital hypertelorism as defined by increased bony interorbital distance is a complex manifestation of many congenital anomalies. As such, it is associated with a multitude of orbital, adnexal, and surrounding soft-tissue deformities. Treatment of these problems requires extensive experience and a comprehensive team, permitting adequate preoperative evaluation, diagnosis, and treatment. The results obtained may be dramatic. The overall safety of the procedures has been demonstrated. Continued refinements and long-term follow-up will undoubtedly continue to make significant improvements.

Bone Diseases, Developmental↗

PubMed1987

Ocular and adnexal complications of unilateral orbital advancement for plagiocephaly.

Strabismus, ptosis, lateral canthal dystopia, nasolacrimal obstruction, and cranial nerve palsy were noted preoperatively in 32%, 21%, 14%, 12%, and 9% of 34 patients, respectively, undergoing ophthalmologic evaluation prior to unilateral orbital advancement for plagiocephaly. Thirty-two percent of the patients had normal preoperative ocular and adnexal examination results. Ptosis, strabismus, and amblyopia were frequently acquired postoperative abnormalities in 29%, 18%, and 18% of the patients, respectively. Forty-four percent of the patients had no new abnormalities following craniofacial surgery.

Child↗

PubMed1987

Three-dimensional computed tomographic imaging.

Recent developments in imaging techniques now allow reconstruction of actual three-dimensional images from computed tomographic data. This article discusses the basic concepts involved in three-dimensional imaging and reviews its potential as a diagnostic and management tool for the clinical ophthalmologist. New computer techniques allow review of actual three-dimensional images in both static and dynamic formats. This can allow the clinician to define more accurately a normal and pathologic anatomy involving skeletal structures in particular.

Eye Diseases↗

PubMed1987

Aesthetic augmentation of the malar-midface structures.

Based on extensive experience with bone grafts for augmentation of the midface-malar region, an implant design has been developed using Proplast. After careful preoperative assessment, a very specific surgical method, described herein, allows precise implant positioning without the need for suture fixation. In many instances, the 6-mm implant can be inserted unchanged. One-hundred and six patients have been operated on using 176 implants over the past 6 years. There were four unilateral infections (2.3 percent of implants and 3.8 percent of patients). None had permanent motor or sensory nerve problems. Fifteen implants (8.5 percent) in 12 patients (11.3 percent) were either removed or repositioned. In those having augmentation for entirely aesthetic reasons, 3 of 60 patients (5.0 percent) required implant removal or repositioning. The incidence of needing to remove or reposition implants has decreased as the technique has evolved.

Esthetics↗

PubMed1987

General body growth in children with clefts of the lip, palate, and craniofacial structure.

This paper discusses general body growth in children with craniofacial clefts. Body growth is important in such patients because morphology reflects the cumulation of metabolism over time. The same hormones that direct general body growth also govern the ontogeny of the head and face. Body growth varies in children with different types of clefts. We found no average differences from US norms for those with isolated clefts of the lip alone or those with bilateral clefts of the lip and palate. Children with unilateral clefts of the lip and palate and with isolated cleft palate were significantly shorter than their unaffected peers. Males with these defects were also thinner than normal based on average standard deviation scores for body mass indices. Both unilateral and bilateral clefts of the lip and palate predominated in males, while isolated cleft lip was more frequent in females. Our results indicate that congenital metabolic variation contributes to the development of orofacial clefting and influences postnatal development in certain types of cleft. Accordingly, cleft type is important to growth prognosis, and growth status is relevant to optimization of therapy in orofacial cleft patients.

Adolescent↗

PubMed1987

Craniosynostosis: an analysis of the timing, treatment, and complications in 164 consecutive patients.

Treatment options for the craniosynostoses vary from conservative observation until completion of growth to radical remodeling in infancy. To further define the timing and type of treatment necessary in these complex disorders, we have retrospectively analyzed all patients operated on for this deformity during the past 12 years. One-hundred and sixty-four patients with craniosynostosis were analyzed and subgrouped into asymmetrical (predominantly unilateral) and symmetrical (bilateral) deformities, in addition to segregation by age and type of procedure performed. This was done recognizing that no deformity, like no normal human face, is truly symmetrical. Results of treatment were categorized on the basis of the need for additional surgery and varied from no refinements necessary (category I) to major reduplication of the initial procedure (category IV). Analysis of the data led us to conclude that excellent results can be expected in the asymmetrical deformities group treated in infancy by a unilateral approach. Similarly, for the mild symmetrical deformities, treatment at this time by bilateral orbital advancement gives satisfactory results in the majority of patients. By contrast, the more severe symmetrical groups treated in childhood have a high incidence of requiring secondary major reconstructions, and consideration should be given to delaying craniofacial surgery until age 7 or older, although earlier cranial surgery may be advisable.

Age Factors↗

PubMed1987

Psychosocial considerations in craniofacial deformity.

The authors evaluate the hypotheses that duration and severity of craniofacial malformations correlate with psychosocial adjustment. Reviewing data from congenital and traumatic craniofacial malformation patients of varying ages, they find partial support for the hypothesized associations; however, the relationship between psychosocial adjustment and craniofacial deformity is far from straightforward.

Adjustment Disorders↗