Faculty Bibliography

The purpose of this study was to develop a nonhuman primate model for heterotopic composite tissue facial transplantation in which to study the natural history of facial transplantation and evaluate immunosuppressive regimens.A composite oromandibular facial segment transplant based on the common carotid artery was evaluated. Flaps from 7 cynomolgus monkeys were transplanted to the groins of 7 recipients at the superficial femoral artery and vein. The immunosuppressive regimen consisted of thymoglobulin, rapamycin, and tacrolimus. Allograft survival ranged from 6 to 129 days. Histology performed in the long-term survivor at the time of necropsy revealed extensive inflammation and necrosis of the allograft skin; however, muscle and bone elements were viable, with minimal inflammation. This heterotopic facial transplantation model avoids the potential morbidity of mandibular resection and orthotopic facial transplantation. Our work also concurs with the work of other groups who found that the skin component is the most antigenic.

INTRODUCTION: Understanding how teeth move in response to mechanical loads is an important aspect of orthodontic treatment. Treatment planning should include consideration of the appliances that will meet the desired loading of the teeth to result in optimized treatment outcomes. The purpose of this study was to evaluate the use of computer simulation to predict the force and the torsion obtained after the activation of tear drop loops of 3 heights. METHODS: Seventy-five retraction loops were divided into 3 groups according to height (6, 7, and 8 mm). The loops were subjected to tensile load through displacements of 0.5, 1.0, 1.5, and 2.0 mm, and the resulting forces and torques were recorded. The loops were designed in AutoCAD software(2005; Autodesk Systems, Alpharetta, GA), and finite element analysis was performed with Ansys software(version 7.0; Swanson Analysis System, Canonsburg, PA). Statistical analysis of the mechanical experiment results was obtained by ANOVA and the Tukey post-hoc test (P < .01). The correlation test and the paired t test (P < .05) were used to compare the computer simulation with the mechanical experiment. RESULTS AND CONCLUSIONS: The computer simulation accurately predicted the experimentally determined mechanical behavior of tear drop loops of different heights and should be considered an alternative for designing orthodontic appliances before treatment.

Werner and Bloom syndromes are human diseases characterized by premature age-related defects including elevated cancer incidence. Using a novel Saccharomyces cerevisiae model system for aging and cancer, we show that cells lacking the RecQ helicase SGS1 (WRN and BLM homologue) undergo premature age-related changes, including reduced life span under stress and calorie restriction (CR), G1 arrest defects, dedifferentiation, elevated recombination errors, and age-dependent increase in DNA mutations. Lack of SGS1 results in a 110-fold increase in gross chromosomal rearrangement frequency during aging of nondividing cells compared with that generated during the initial population expansion. This underscores the central role of aging in genomic instability. The deletion of SCH9 (homologous to AKT and S6K), but not CR, protects against the age-dependent defects in sgs1Delta by inhibiting error-prone recombination and preventing DNA damage and dedifferentiation. The conserved function of Akt/S6k homologues in lifespan regulation raises the possibility that modulation of the IGF-I-Akt-56K pathway can protect against premature aging syndromes in mammals.

Objective: This series of laboratorial and in-vivo studies describe the characterization, evolution, and in-vivo performance of various Ca- and P-based nanothicknesses and microstructures ion beam assisted depositions (IBAD) onto Ti-6Al-4V implants. Materials and Methods: Characterization- The 4 mm in diameter and 10 mm in length implant rods (Ti-6Al-4V) with IBAD 1, IBAD 11, and control (alumina-blasted/acid-etched, AB/AE) surfaces were provided by an implant manufacturer. The in-vitro characterization comprised the following techniques: (1) SEM/EDS, (2) XPS/Depth Profiling (3) Thin-film XRD (4) AFM + ToF-SIMS for coating thickness determination (5) AFM- Ra determination. In-vivo- Three animal experiments were carried out for evaluation of the nanothickness bioceramic coatings. All experiments comprised a proximal tibia model with 4-6 implants placed along the bones. Times in-vivo ranged from 2-5 weeks. Static (bioactivity, bone to implant contact) and dynamic (mineral apposition rates- MAR) histomorphometric measurements were recorded. Biomechanical testing was performed by pullout and torque to interfacial failure testing. Results. Combination of the characterization techniques showed that all bioceramic coatings were Ca- and P-based bioceramics of amorphous microstructure. AFM +ToF-SIMS showed that IBAD 11 coatings were thicker (300-500 nm) compared to IBAD I coatings (30-50 nm). Surface roughness did not change significantly for the IBAD implant groups compared to control. The in-vivo results showed higher degrees of osseoactivity, torque to failure, and MAR for the coated implants at different times in-vivo. [BAD 11 had higher biomechanical fixation at early implantation times compared to other groups. Conclusions: The results obtained in the in-vitro part this study support that both IBAD I and IBAD 11 coatings are Ca- and P- based amorphous bioceramics in the nanothickness range with theoretical high dissolution rates. The increased osseoactivity observed for [BAD coated and the high MAR v allies observed for IBAD coated compared to AB/AE implants support the effect of the bioceramic coating presence in the overall bone healing. A thickness effect was reveled through biomechanical testing where IBAD 11 (300-500nm thickness) presented higher performance.

OBJECTIVE: Tympanostomy tube insertion is the most common procedure that requires general anesthesia for children in the United States. We report on the clinical characteristics of a cohort of New York City children who received tympanostomy tubes in 2002. METHODS: This retrospective cohort study included all 1046 children who received tubes in 2002 in any of 5 New York City area hospitals. We analyzed clinical data for all 682 (65%) children for whom we were able to abstract data for the preceding year from all of 3 sources: hospital, pediatrician, and otolaryngologist medical charts. RESULTS: Mean age was 3.8 years, 57% were male, and 74% had private insurance. More than 25% of children had received tubes previously. The stated reason for surgery was otitis media with effusion for 60.4% of children, recurrent acute otitis media for 20.7%, and eustachian tube dysfunction for 10.6%. Children with recurrent acute otitis media averaged 3.1 +/- 0.2 episodes (median: 3.0) in the previous year; those with otitis media with effusion averaged effusions that were 29 +/- 1.7 days long (median: 16 days) at surgery. Twenty-five percent of children had bilateral effusions of >42 days' duration at surgery. Despite a clinical practice guideline for otitis media with effusion that recommends withholding tympanostomy tubes for otherwise healthy children until a bilateral effusion is at least 3 to 4 months old, 50% of children had surgery without having had 3 months of effusion cumulatively during the year before surgery. CONCLUSIONS: The clinical characteristics of children who received tympanostomy tubes varied widely. Many children with otitis media with effusion had shorter durations of effusions than are generally recommended before surgery. The extent of variation in treating this familiar condition with limited treatment options suggests both the importance and the difficulty of managing common practice in accordance with clinical practice guidelines

AIM: Static Hertzian contact tests of monolayer glass-ceramics in trilayer configurations (glass-ceramic/cement/composite) have shown that thick cement layers lower strength. This study sought to test the hypothesis that thick resin cement layers lower mouth motion fatigue reliability for flat glass-ceramic/cement/composite trilayer systems and that aging in water reduces reliability. METHODS: Dicor plates (n > or = 12 per group) (10 x 10 x 0.8 mm(3)) were aluminum-oxide abraded (50 microm), etched (60 s), silanized, and bonded (Rely X ARC) to water aged (30 days) Z100 resin blocks (10 x 10 x 4 mm(3)). Four groups were prepared: (1) thick cement layer (>100 microm) stored in water for 24-48 h, (2) thick cement layer stored for 60 days, (3) thin cement layer (< or =100 microm) stored for 24-48 h, and (4) thin cement layer stored for 60 days. The layered structures were fatigued (2 Hz) utilizing mouth motion loading with a step-stress acceleration method. A master Weibull distribution was calculated and reliability determined (with 90% confidence intervals) at a given number of cycles and load. RESULTS: The aged group (60 d) with thick cement layer had statistically lower reliability for 20,000 cycles at 150 N peak load (0.11) compared with both nonaged groups (24-48 h) (thin layer = 0.90 and thick layer = 0.82) and aged group with thin cement layer (0.89). CONCLUSION: Trilayer specimens with thick cement layers exhibited significantly lower reliability under fatigue testing only when stored for 60 days in water. The hypothesis was accepted. These results suggest that diffusion of water into the resin cement and also to the glass-ceramic interface is delayed in the thick cement specimens at 24-48 h.

OBJECTIVE: To review the background, case characteristics, and outcomes of malpractice litigation resulting from surgical injury of the spinal accessory nerve. DESIGN: Retrospective review of indemnity insurance cases (part 1) and court trials (part 2) between January 1, 1985, and January 1, 2007. In part 1, records of the Medical Liability Mutual Insurance Company identified 41 lawsuits in New York State; part 2 was a review of a national legal database (WestLaw) that identified 81 court trials. Case details were analyzed, and awards were adjusted for inflation. RESULTS: For part 1, of 41 indemnity insurance cases, 39 (95%) involved a posterior triangle lymph node biopsy. Defendants were mainly general surgeons and otolaryngologists. Most lawsuits against surgeons (22 of 34 [65%]) were settled before trial, and only 4 of 34 (12%) were discontinued. Of these 34 cases, 28 (82%) ultimately compensated the plaintiff. The mean inflation-adjusted pretrial settlement was $264 395, and the mean settlement at trial was $443 538. Cases reaching trial received significantly higher settlements (P = .01). For part 2, 81 cases of alleged surgical injury to the spinal accessory nerve were identified. Defendant physicians were mainly general surgeons and otolaryngologists. Most operations were cervical lymph node biopsies (55 [68%]), followed by sebaceous cyst excisions (6 [7%]), neck dissections (4 [5%]), and other procedures (12 [15%]). Morbidity included weakness (81 patients [100%]), pain (30 patients [37%]), inability to work (20 patients [25%]), need for a nerve repair procedure (16 patients [20%]), deformity (9 patients [11%]), and numbness (4 patients [5%]). Types of malpractice alleged included negligent surgical technique (79 cases [98%]), lack of informed consent (17 cases [21%]), and failure to diagnose the injury (16 cases [20%]). Thirty-seven cases (46%) were decided for the defendant, 32 (40%) were decided for the plaintiff, and 12 (15%) were settled (percentages do not total 100 because of rounding). The mean inflation-adjusted settlement was $356 132, and the mean jury award was $515 968. Jury awards were significantly higher than settlements (P = .003). CONCLUSIONS: Unintended injury to the spinal accessory nerve after head and neck surgery is a significant source of malpractice litigation. Timely diagnosis and treatment of this complication are essential. Regardless of whether the medical community considers careful surgical technique and nerve preservation to be the standard of care, the legal system clearly treats it as such, awarding compensation in 82% of cases. Strategies for optimal surgical care and litigation risk reduction are discussed