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Biomedical subjects

S A Schendel

Publications and source records attributed to S A Schendel.

At least 19 recordsLinked to original sources
PubMed1998

Studies in cranial suture biology: up-regulation of transforming growth factor-beta1 and basic fibroblast growth factor mRNA correlates with posterior frontal cranial suture fusion in the rat.

The mechanisms involved in normal cranial suture development and fusion as well as in the pathophysiology of craniosyostosis are not well understood. The purpose of this study was to investigate the expression of several cytokines--transforming growth factor-beta-1 (TGF-beta1), basic fibroblast growth factor (bFGF), and interleukin-6 (IL-6)--during cranial suture fusion. TGF-beta exists in three mammalian isoforms that are abundant in bone and stimulate calvarial bone formation when delivered locally. Other bone growth factors including basic fibroblast growth factor and the interleukins regulate bone growth and are mitogenic for bone marrow cells and osteoblasts. The involvement of growth factors in the pathophysiology of craniosynostosis is supported by recent genetics data linking fibroblast growth factor receptor mutations to syndromal craniosynostoses. In this experimental study, in situ hybridization was used to localize and quantify the gene expression of TGF-beta1, bFGF, and IL-6 during cranial suture fusion. In the Sprague-Dawley rat, the posterior frontal cranial suture normally undergoes fusion between 12 and 22 days of age, whereas all other cranial sutures remain patent. All in situ analyses of fusing posterior frontal sutures were compared with the patent, control, sagittal sutures. Posterior frontal and sagittal sutures, together with underlying dura, were harvested from rats at 8, 12, 16, and 35 days of postnatal life to analyze posterior frontal suture activity before, during, and after fusion. In situ hybridization was performed on frozen sections of these specimens using DNA probes specific for TGF-beta1, bFGF, and IL-6 mRNA. A negative control probe to IL-6 in the sense orientation was also used to validate the procedure. Cells expressing cytokine-specific mRNA were quantified (in cells positive per 10(-1) mm2) and analyzed using the unpaired Student's t test. Areas encompassing the fibrous suture and the surrounding bone plates were analyzed for cellular mRNA activity. IL-6 mRNA expression showed a minimal rise in the posterior frontal suture at days 12 and 16, with an average count of 10 and 6 cells per 10(-1) mm2, respectively. The sagittal suture remained negative for IL-6 mRNA at all time points. TGF-beta1 and bFGF analyses were most interesting, showing marked increases specifically in the posterior frontal suture during the time of active suture fusion. On postnatal day 8, a 1.5-fold increase in posterior frontal suture TGF-beta1 mRNA was found compared with sagittal sutures (p = 0.1890, unpaired Student's t test). This difference was increased 26-fold on day 12 in posterior frontal suture TGF-beta1 expression (p = 0.0005). By day 35, posterior frontal suture TGF-beta1 mRNA had nearly returned to prefusion levels, whereas TGF-beta1 mRNA levels in the sagittal suture remained low. A similar upregulation of bFGF mRNA, peaking at day 12, was observed in posterior frontal but not sagittal sutures (p = 0.0003). Furthermore, both TGF-beta1 and bFGF mRNA samples with intact dura showed an intense dural mRNA expression in the time preceding and during active posterior frontal suture fusion but not in sagittal tissues. Our data demonstrate that TGF-beta1 and bFGF mRNA are up-regulated in cranial suture fusion, possibly signaling in a paracrine fashion from dura to suture. TGF-beta1 and bFGF gene expression were dramatically increased both in and surrounding the actively fusing suture and followed the direction of fusion from endocranial to epicranial. These experimental data on bone growth factors support the recent human genetics data linking growth factor/fibroblast growth factor receptor deletions to syndromal craniosynostoses. The ultimate aim of these studies is to understand the underlying mechanisms regulating suture growth, development, and fusion so surgeons may one day manipulate the biology of premature cranial suture fusion.

Animals↗
PubMed1997

Adverse outcomes in orthognathic surgery and management of residual problems.

Adverse outcomes in orthognathic surgery include both functional and aesthetic components that frequently coexist. Reasons for this occurrence are multifactorial and can be classified in broad categories of diagnosis, treatment planning, technical execution, and unpreventable outcomes. Management of the residual deformities is both functional and aesthetic as based on correctly delineating the problem and its cause.

Craniofacial Abnormalities↗
PubMed1996

Treatment of periorbital edema with human corticotropin-releasing factor after blepharoplasty.

BACKGROUND: This prospective study of 32 patients was undertaken to ev evaluate the formation of postoperative periorbital edema after administration of human corticotropin-releasing factor (hCRF). Human corticotropin-releasing factor has strong antiedematous properties as a result of direct action on blood vessels independent of endocrine function and has been shown to have a positive effect on vascular permeability in animal studies independent of corticosteroid effects. STUDY DESIGN: Human corticotropin-releasing factor was administered intravenously preoperatively to patients undergoing blepharoplasty in doses of 2, 4, and 8 mu g/kg body weight as a randomized, double-blind, placebo-controlled study. The periorbital edema was measured by the use of a three-dimensional laser scanner to determine facial and eyelid volume changes as specified times postoperatively. RESULTS: Human corticotropin-releasing factor was well tolerated when administered intravenously over a ten-minute period to healthy patients undergoing blepharoplasty. Mild transitory flushing and hypotension were the most common adverse events. Transient decreases in systolic and diastolic blood pressure and increases in heart rate occurred at hCRF doses greater than 2 mu g/kg and were most prominent at 8 mu g/kg. The 8 mu g/kg hCRF dose also showed a trend toward less postoperative edema but this was not statistically significant at the p<0.05 level. CONCLUSIONS: Human corticotropin-releasing factor appears to be safe for intravenous use in patients undergoing blepharoplasty; however, its efficacy in reducing postoperative edema as a single preoperative administration was not conclusively demonstrated in this study. Further research with a larger study population and other dosing regimens is indicated.

Corticotropin-Releasing Hormone↗
PubMed1995

Treatment of the craniofacial complications of Beckwith-Wiedemann syndrome.

Variable degrees of macroglossia have been noted in patients with Beckwith-Wiedemann syndrome. Past studies have shown that a major effect of the macroglossia is protrusion of dentoalveolar structures, resulting in an anterior open bite and a prognathic mandibular appearance secondary to an abnormally obtuse gonial angle and increased effective mandibular length. In our series of 11 Beckwith-Wiedemann syndrome patients we have observed that early correction of the macroglossia by means of partial glossectomy has resulted in decreased anterior open bite and mandibular prognathism as compared with patients managed conservatively.

Beckwith-Wiedemann Syndrome↗
PubMed1995

Expanding cranial defects following craniofacial surgery.

Growing skull fractures or posttraumatic leptomeningeal cysts are a known complication of skull fractures sustained in infancy and childhood. They usually present as progressively enlarging cranial masses at the site of the linear skull fractures. The pathogenesis is believed to require an underlying dural tear that allows herniation of the growing pulsatile brain and leads to resorption of the overlying bone. Similar enlarging cranial masses have been reported following craniofacial surgery. Our case occurred following reconstruction of a stenosed metopic suture. The treatment of this unusual complication of craniofacial surgery requires sound dural repair. An understanding of the similarity between this complication and the more common growing skull fractures of childhood is essential to a sound approach to diagnosis and treatment.

Craniosynostoses↗
PubMed1995

Correction of scaphocephaly secondary to ventricular shunting procedures.

Craniosynostosis following ventricular shunting procedures for hydrocephalus has become a recognized complication of shunting procedures. Secondary synostosis results from a decrease in intracranial volume leading to collapse of the cranial vault. Since this represents a distinct etiopathogenesis different from that typically involved, the surgical approach should be altered. Eight patients with secondary scaphocephaly underwent surgical reconstruction. The clinical data and radiographic studies were reviewed for these patients. The surgical approach consisted of sagittal or parasagittal strip craniectomies, lateral osteotomies with bone-flap expansion, occipital and frontal remodeling as needed, and the application of rigid fixation to maintain contour and prevent recurrent collapse of the cranial vault. Patient follow-up ranged from 3 to 37 months. Five of these patients were premature infants, an association not previously recognized in the literature. Satisfactory results were obtained in all patients. Keeping the craniectomy sites parent and achieving a more normal cranial contour through cranial remodeling have provided good results in this population.

Cerebrospinal Fluid Shunts↗
PubMed1994

Histochemical analysis of cleft palate muscle.

Research has clarified the abnormal insertions and orientations of the involved musculature in cleft palate. However, little is known about the physiologic aspects of these muscles, specifically from a histochemical perspective. In this study, 30 muscle specimens were removed from the palatal cleft margin in patients undergoing primary palatoplasty. Nine patients had combined cleft lip and palate deformity, and seven had an isolated cleft palate. Biopsies were taken from the area of the musculus uvulus in all specimens and examined by histochemical techniques. The percentage of type 1 and type 2 fibers was different in isolated cleft palate as compared with cleft lip and palate specimens, being, respectively, 56.7 percent type 1 and 43.3 percent type 2 and 62.0 percent type 1 and 38.0 percent type 2 fibers. This is the opposite ratio from other facial muscles but is in line with the literature regarding normal palatal muscle. Isolated cleft palate muscle fibers also were minimally decreased in diameter as compared with normal facial muscle. Fiber diameters of the combined cleft lip and palate muscles were severely decreased in size compared with those muscles found in the cleft lip. Abnormal mitochondrial accumulations also were found in cleft lip and palate muscle specimens but not in isolated cleft palate muscle specimens. We consider the decrease in muscle diameter found in isolated cleft palate to be secondary to functional atrophy, while that in the cleft lip and palate specimens is secondary to a primary hypoplasia together with a functional atrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1994

The association of cleft lip and palate with Aicardi syndrome.

In summary, Aicardi syndrome is defined by its tetrad of infantile spasms, agenesis of the corpus callosum, mental retardation, and chorioretinal lacunae. We report a case of Aicardi syndrome with associated cleft lip and palate. This is an infrequent finding that is present in approximately 3 percent of reported cases. Plastic surgeons should be aware of this association when treating patients with cleft lip and palate.

Brain↗
PubMed1992

An analysis of Le Fort I maxillary advancement in cleft lip and palate patients.

We present a series of 24 consecutive cleft lip and palate patients aged 16 to 46 years (mean age 27 years) who underwent Le Fort I maxillary advancement by the senior author over the past 8 years. Two groups, one of 12 patients with wire fixation and one of 12 patients with miniplate fixation, were evaluated. Each group had 10 unilateral and 2 bilateral clefts. All patients were grafted with autogenous bone (8 cranial, 14 iliac, and 2 mandibular). Horizontal advancement was 3 mm to 2 cm (with a mean of 7.8 mm). Vertical movement ranged from a shortening of 5 mm to a lengthening of 1.3 cm (mean 2.3 mm of lengthening). The amount and timing of relapse were compared in both the horizontal and vertical dimensions. The plated group was more stable in both the horizontal and vertical dimensions (p < 0.05). No significant skeletal relapses occurred after the first year. Statistically significant dental relapse occurred only in the wired group. Three patients developed transverse collapse of the small maxillary cleft segment, and four developed incisor angulation to compensate for maxillary skeletal relapse. The presence of a pharyngeal flap at the time of advancement appeared to increase relapse in both horizontal and vertical dimensions (p < 0.03), but there were too few patients (7 of 24) with pharyngeal flaps to prove this conclusively. We also concluded that pterygomandibular grafting is not necessary to achieve excellent results using miniplate fixation; autogenous grafting of the anterior maxillary osteotomy alone provides the necessary stability.

Adult↗
PubMed1992

New technique?

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Humans↗
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↗