Faculty Bibliography

Presurgical infant orthopedics has been employed since 1950 as an adjunctive neonatal therapy for the correction of cleft lip and palate. Most of these therapies did not address deformity of the nasal cartilage in unilateral and bilateral cleft lip and palate as well as the deficiency of the columella tissue in infants with bilateral cleft. The nasolaveolar molding (NAM) technique a new approach to presurgical infant orthopedics developed by Grayson reduces the severity of the initial cleft alveolar and nasal deformity. This enables the surgeon and the patient to enjoy the benefits associated with repair of a cleft deformity that is minimal in severity. This paper will discuss the appliance design, clinical management and biomechanical principles of nasolaveolar molding therapy. Long term studies on NAM therapy indicate better lip and nasal form, reduced oronasal fistula and labial deformities, 60 % reduction in the need for secondary alveolar bone grafting. No effect on growth of midface in sagittal and vertical plane has been recorded up to the age of 18 yrs. With proper training and clinical skills NAM has demonstrated tremendous benefit to the cleft patients as well as to the surgeon performing the repair

BACKGROUND: Bone engineering requires thicker three-dimensional constructs than the maximum thickness supported by standard cell-culture techniques (2 mm). A flow-perfusion bioreactor was developed to provide chemotransportation to thick (6 mm) scaffolds. METHODS: Polyurethane scaffolds, seeded with murine preosteoblasts, were loaded into a novel bioreactor. Control scaffolds remained in static culture. Samples were harvested at days 2, 4, 6, and 8 and analyzed for cellular distribution, viability, metabolic activity, and density at the periphery and core. RESULTS: By day 8, static scaffolds had a periphery cell density of 67% +/- 5.0%, while in the core it was 0.3% +/- 0.3%. Flow-perfused scaffolds demonstrated peripheral cell density of 94% +/- 8.3% and core density of 76% +/- 3.1% at day 8. CONCLUSIONS: Flow perfusion provides chemotransportation to thick scaffolds. This system may permit high throughput study of 3D tissues in vitro and enable prefabrication of biological constructs large enough to solve clinical problems

BACKGROUND: To improve the ability to prognosticate the final surgery outcomes, this study was carried out to explore the correlation between the number of motor axons given to cross-facial nerve grafts for smile restoration and the aesthetic and functional outcomes. METHODS: Sixty-nine cases had adequate nerve biopsy specimens and were selected for the authors' study. Patient information was collected from chart review. Using Terzis' evaluation scale, smile functional and aesthetic outcomes as depicted in standardized videos were graded by a panel of four independent reviewers. Digital images of nerve specimens in stages I and II were obtained by using a microscope with a digital camera attachment. Using MetaMorph software, the number of motor axons was calculated, with the exception of the nerve specimens at the distal nerve grafts in stage II, which were quantitated manually. Mann-Whitney and Fisher's exact tests were used to test the effects of axon numbers and other factors on the outcomes. RESULTS: The donor axonal input correlated with the axon number at the distal end of the nerve graft and also correlated with the improvement of evaluation; however, no significance was found between the counts at the distal end of the nerve graft and the clinical outcomes. An important observation was that patients with a donor nerve count of 900 or higher showed a greater likelihood of achieving satisfactory results. CONCLUSION: The axon count at the donor nerve has a stronger influence on the final results

BACKGROUND: Most reconstructions for lower lip palsy focus on paralyzing the contralateral normal lip or providing static support on the affected side. The authors' unit has reported dynamic strategies for lower lip reanimation and use of 40 percent of the hypoglossal nerve (mini-hypoglossal) in facial reanimation. They report their experience with mini-hypoglossal nerve transfer for lower lip palsy. METHODS: Between 1987 and 2005, 29 patients with unilateral facial palsy had lower lip reanimation with the mini-hypoglossal as the motor donor. Twenty patients had transfer of the mini-hypoglossal to the cervicofacial branch of the facial nerve and nine had direct depressor muscle neurotization. Five patients had a mean denervation time of 14.60 +/- 4.50 months (<2 years), and the rest had a mean denervation time of 10.63 +/- 9.23 years. In late cases, the facial nerve was in-continuity, and preoperative needle electromyographs of depressors showed at least fibrillations. Standardized videos taken preoperatively and at 2 years postoperatively were available for 27 patients and assessed by three independent reviewers. Needle electromyographic results were analyzed. RESULTS: Thirteen patients (48.15 percent) achieved excellent and good results, nine (33.33 percent) had moderate results, and five (18.52 percent) obtained fair results. The difference between the averaged preoperative and postoperative scores was statistically significant, as was the difference in electromyographic outcomes (p < 0.0001, Wilcoxon signed rank test). The nerve transfer and direct neurotization groups had no statistically significant difference in clinical and electromyographic outcomes. Four patients required muscle transfer for further outcome upgrading. CONCLUSION: Use of the mini-hypoglossal either for nerve transfer or for direct muscle neurotization of lower lip depressors can provide reinnervation and satisfactory clinical function, even for muscles with prolonged partial denervation

Objectives: To report changes in survival probabilities as patients survive one or more years with head and neck melanoma, and to characterize prognostic factors for this conditional survival statistic. Study Design: Retrospective population-based cohort study. Methods: All subjects from the Surveillance, Epidemiology and End Results (SEER 17) database of the National Cancer Institute with head and neck cutaneous melanoma were analyzed. Using the life table actuarial method, conditional 5 year disease specific survival (DSS) and relative survival were determined for patients surviving one to ten years after diagnosis. Grouped comparisons were performed for anatomic subsites within the head and neck and the rest of the body. Probabilities were also stratified by histologic subtype, thickness of invasion and lymph node status. Results: Five year DSS for scalp and neck melanomas increases from 83.1% to 93.9% for patients surviving five years, compared to an increase from 89.2% to 96.2% for other anatomic sites. Nodular melanoma displayed the worst initial survival among histologic subtypes (73.4%) but improves to 91% at five years. Conditional DSS for node positive patients improves from 47.9% to 83.1%. Survival at diagnosis is stratified by tumor thickness from 96.7% (T1) to 62.3% (T4), but tends to converge between five to ten years of survivorship. Conclusions: For patients with head and neck melanoma who have survived several years, conditional survival provides accurate and useful prognostic information. In general, expected survival increases with time survived since diagnosis, and for low and high T-stage patients, conditional survival statistics converge over time

BACKGROUND: Le Fort III distraction osteogenesis improves midface form and dental relationships in patients with syndromic craniosynostosis, but its effect on the upper airway is not well documented. METHODS: A retrospective review was conducted of patients with syndromic craniosynostosis undergoing Le Fort III distraction osteogenesis from 2000 to 2006 (n = 20). Changes in velar angle and nasopharyngeal, velopharyngeal, oropharyngeal, and hypopharyngeal spaces were measured cephalometrically. Three-dimensional airway casts were created from computed tomographic data to ascertain circumferential airspace changes. Patients with the preoperative diagnosis of severe obstructive sleep apnea or a tracheostomy were designated as having significant airway compromise. Cephalometric differences in the preoperative superior airspace were compared between patients with and without significant airway compromise. Improvement in the symptoms of obstructive sleep apnea was studied. RESULTS: Cephalometric analysis revealed an increase in the velar angle (121 degrees to 148 degrees; p < 0.001) and an increase in the nasopharyngeal (3.9 mm to 13.0 mm; p < 0.001) and velopharyngeal airspaces (2.0 mm to 5.9 mm; p < 0.01). Three-dimensional computed tomographic analysis confirmed these findings. Comparison between preoperative cephalograms of patients with (n = 10) and without significant airway compromise (n = 10) revealed smaller nasopharyngeal (2.2 mm versus 5.7 mm; p < 0.05) and velopharyngeal airspaces (0.9 mm versus 3.0 mm; p = 0.05). Nine of 10 patients with significant airway compromise experienced improvement in their symptoms of obstructive sleep apnea or had their tracheostomy removed. CONCLUSIONS: Le Fort III distraction osteogenesis significantly increases nasopharyngeal and velopharyngeal airspaces in patients with syndromic craniosynostosis. Midface distraction improves but does not resolve all causes of obstructive sleep apnea in this patient population

Hedgehog signaling is often activated in tumors, yet it remains unclear how GLI2, a transcription factor activated by this pathway, acts as an oncogene. We show that GLI2 is a pleiotropic oncogene. The overexpression induces genomic instability and blocks differentiation, likely mediated in part by enhanced expression of the stem cell gene SOX2. GLI2 also induces transforming growth factor (TGF)B1-dependent transdifferentiation of foreskin and tongue, but not gingival fibroblasts into myofibroblasts, creating an environment permissive for invasion by keratinocytes, which are in various stages of differentiation having downregulated GLI2. Thus, upregulated GLI2 expression is sufficient to induce a number of the acquired characteristics of tumor cells; however, the stroma, in a tissue-specific manner, determines whether certain GLI2 oncogenic traits are expressed

PURPOSE: Mechanical analyses of idealized crown-cement-tooth systems through finite element analysis (FEA) has provided valuable insight concerning design parameters and materials that favor lower stress patterns. However, little information regarding variation of basic preparation guidelines in stress distribution has been available. The primary objective of this study was to evaluate maximum principal stresses on a molar crown veneer plus core system natural tooth configuration preparation with variations in the ratio of proximal axial length (PAL) to buccal axial length (BAL) as well as loading condition and position. MATERIALS AND METHODS: Three-dimensional models comprising a crown veneer (porcelain), crown core (zirconia), cement layer, and tooth preparation (4.2 mm BAL with PAL reductions of 0.8 mm, 1.0 mm, and 1.2 mm) yielding BAL:PAL ratios of 1.23, 1.31, and 1.4 were designed by computer software (Pro/Engineering). The models were imported into an FEA software (Pro/Mechanica), with all degrees of freedom constrained at the root surface of the tooth preparation. Each tooth preparation crown configuration was evaluated under a vertical (axial) 200 N load, and under a combined vertical 200 N and horizontal (buccally) 100 N load applied at different positions from the central fossa to the cusp tip. Maximum principal stress (MPS) was determined for the crown core for each crown BAL:PAL ratio, loading condition, and position. RESULTS: Under both vertical and combined loading conditions, the highest MPSs were located at the occlusal region and in the occlusogingival region of the ceramic core. MPS values increased in the proximal region as the BAL:PAL ratio increased. Combined loading resulted in a general increase in MPS compared to vertical loading. CONCLUSION: Increasing the BAL:PAL ratio (reducing the proximal axial length of the preparation) acted as a stress concentrator at regions near the crown margins, suggesting this area may be vulnerable to damage from fit adjustment as well as during function. Such increases in stress concentration should be considered in clinical scenarios, especially when inherent flaws are present in the material, since extensive high-magnitude tensile stress fields have been noted under all loading conditions