Faculty Bibliography

Restoration of elbow flexion is one of the priorities in brachial plexus palsy, as this function brings the hand to the mouth. This study analyses the results of musculocutaneous nerve reconstruction in 194 patients with devastating paralysis. Results were analyzed in relation to denervation time, severity score, length of nerve grafts, and donor nerves used. Between 1978 and 2006, 194 post-traumatic plexopathy patients underwent musculocutaneous nerve reconstruction. 298 motor donors were used in 175 patients while 19 patients had microneurolysis. There were 104 intraplexus motor donors; 124 intercostal nerves were transferred in 39 patients; direct coaptation was performed in 31 patients and three or more intercostals were transferred in 33 patients; 16 patients underwent musculocutaneous to musculocutaneous repair. 144 patients had interposition nerve grafts. The mean follow-up was 4.48 +/- 2.78 years. Results were good or excellent (>/=M3+) in 52.53% of patients with more than 70 degrees of elbow flexion. Patients, who were operated on less than 4 months from injury, with high severity score, attained significant better results than late cases with multiple root avulsions. Intraplexus donors have direct influence on biceps recovery, achieving significant better results than extraplexus donors. Intercostal nerves are an alternative source in avulsion injuries. The use of 3 intercostals with direct coaptation yielded optimal elbow flexion. Musculocutaneous nerve reconstruction is one of the priorities in upper limb reanimation. Functional outcomes are influenced by the age of the patient, severity of plexus lesion, denervation time, and type of reconstruction. Early surgery is recommended.

Laser metal sintering has shown promising results, but no comparison with other commercially available surface has been performed. This study sought to evaluate the biomechanical and histological early bone response to laser sintered implants relative to alumina-blasted/acid-etched (AB/AE). Surface topography was characterized by scanning electron microscopy and optical interferometry. Surface chemistry was assessed by x-ray photoelectron spectroscopy. Beagle dogs (n = 18) received 4 Ti-6Al-4V implants (one per surface) in each radius, remaining for 1, 3, and 6 weeks (n = 6 dogs per evaluation time) in vivo. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were evaluated. Biomechanical evaluation comprised torque-to-interface failure. The laser sintered surface presented higher S(a) and S(q) than AB/AE. Chemistry assessment showed the alloy metallic components along with adsorbed carbon species. Significantly higher torque was observed at 1 (p < 0.02) and 6 week (p < 0.02) for the laser sintered, whereas at 3 week no significant differences were observed. Significantly higher BIC and BAFO was observed for the Laser Sintered (p < 0.04, and p < 0.03, respectively) only at 1 week, whereas no significant differences were observed at 3 and 6 weeks. The laser sintered implants presented biocompatible and osseoconductive properties and improved biomechanical response compared with the AB/AE surface only at 1 and 6 weeks in vivo.

Objective. To investigate whether porcine-derived bioresorbable pericardium membrane coverage enhances the osseointegration around implants placed in fresh extraction sockets. Study Design. Twenty-four commercially available endosseous implants were placed in the fresh extraction sockets of the mandibular first molar of mature beagles (n = 6). On one side, implants and osteotomy sites were covered with porcine-derived bioresorbable pericardium membranes, whereas on the other side, no membranes were used. After 6 weeks, samples were retrieved and were histologically processed for histomorphometric analysis. Results. The histological observation showed that bone loss and soft tissue migration in the coronal region of the implant were evident for the control group, whereas bone fill was evident up to the neck of the implant for the membrane-covered group. Bone-to-implant contact was significantly higher for the membrane-covered group compared to the control group, 75% and 45% (P < 0.02), respectively. Conclusion. The experimental membranes proved to regenerate bone around implants placed in fresh extraction sockets without soft tissue intrusion.

As a strain rate-dependent material, bone has a different mechanical response to various loads. Our aim was to evaluate the effect of water and different loading/unloading rates on the nanomechanical properties of canine femur cortical bone. Six cross-sections were cut from the diaphysis of six dog femurs and were nanoindented in their cortical area. Both dry and wet conditions were taken into account for three quasistatic trapezoid profiles with a maximum force of 2000 muN (holding time = 30 s) at loading/unloading rates of 10, 100, and 1000 muN/s, respectively. For each specimen, 254 +/- 9 (mean +/- SD) indentations were performed under different loading conditions. Significant differences were found for the elastic modulus and hardness between wet and dry conditions (P < 0.001). No influence of the loading/unloading rates was observed between groups except for the elastic modulus measured at 1000 muN/s rate under dry conditions (P < 0.001) and for the hardness measured at a rate of 10 muN/s under wet conditions (P < 0.001). Therefore, for a quasistatic test with peak load of 2000 muN held for 30 s, it is recommended to nanoindent under wet conditions at a loading/unloading rate of 100-1000 muN/s, so the reduced creep effect allows for a more accurate computation of mechanical properties.

Objective. To characterize the topographic and chemical properties of 2 bioceramic coated plateau root form implant surfaces and evaluate their histomorphometric differences at 6 and 12 weeks in vivo. Methods. Plasma sprayed hydroxyapatite (PSHA) and amorphous calcium phosphate (ACP) surfaces were characterized by scanning electron microscopy (SEM), interferometry (IFM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). Implants were placed in the radius epiphysis, and the right limb of dogs provided implants that remained for 6 weeks, and the left limb provided implants that remained 12 weeks in vivo. Thin sections were prepared for bone-to-implant contact (BIC) and bone-area-fraction occupancy (BAFO) measurements (evaluated by Friedman analysis P < 0.05). Results. Significantly, higher S(a) (P < 0.03) and S(q) (P < 0.02) were observed for ACP relative to PSHA. Chemical analysis revealed significantly higher HA, calcium phosphate, and calcium pyrophosphate for the PSHA surface. BIC and BAFO measurements showed no differences between surfaces. Lamellar bone formation in close contact with implant surfaces and within the healing chambers was observed for both groups. Conclusion. Given topographical and chemical differences between PSHA and ACP surfaces, bone morphology and histomorphometric evaluated parameters showed that both surfaces were osseoconductive in plateau root form implants.

This study investigated the effect of an Argon-based atmospheric pressure plasma (APP) surface treatment operated chairside at atmospheric pressure conditions applied immediately prior to dental implant placement in a canine model. Surfaces investigated comprised: rough titanium surface (Ti) and rough titanium surface + Argon-based APP (Ti-Plasma). Surface energy was characterized by the Owens-Wendt-Rabel-Kaelble method and chemistry by X-ray photoelectron spectroscopy (XPS). Six adult beagles dogs received two plateau-root form implants (n = 1 each surface) in each radii, providing implants that remained 1 and 3 weeks in vivo. Histometric parameters assessed were bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Statistical analysis was performed by Kruskall-Wallis (95% level of significance) and Dunn's post-hoc test. The XPS analysis showed peaks of Ti, C, and O for the Ti and Ti- Plasma surfaces. Both surfaces presented carbon primarily as hydrocarbon (C-C, C-H) with lower levels of oxidized carbon forms. The Ti-Plasma presented large increase in the Ti (+11%) and O (+16%) elements for the Ti- Plasma group along with a decrease of 23% in surface-adsorbed C content. At 1 week no difference was found in histometric parameters between groups. At 3 weeks significantly higher BIC (>300%) and mean BAFO (>30%) were observed for Ti-Plasma treated surfaces. From a morphologic standpoint, improved interaction between connective tissue was observed at 1 week, likely leading to more uniform and higher bone formation at 3 weeks for the Ti-Plasma treated implants was observed.

Aim. This study aimed to observe the morphological and molecular effect of laminin-1 doping to nanostructured implant surfaces in a rabbit model. Materials and Methods. Nanostructured implants were coated with laminin-1 (test; dilution, 100 mug/mL) and inserted into the rabbit tibiae. Noncoated implants were used as controls. After 2 weeks of healing, the implants were removed and subjected to morphological analysis using scanning electron microscopy (SEM) and gene expression analysis using the real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Results. SEM revealed bony tissue attachment for both control and test implants. Real-time RT-PCR analysis showed that the expression of osteoblast markers RUNX-2, osteocalcin, alkaline phosphatase, and collagen I was higher (1.62-fold, 1.53-fold, 1.97-fold, and 1.04-fold, resp.) for the implants modified by laminin-1 relative to the control. All osteoclast markers investigated in the study presented higher expression on the test implants than controls as follows: tartrate-resistant acid phosphatase (1.67-fold), calcitonin receptor (1.35-fold), and ATPase (1.25-fold). The test implants demonstrated higher expression of inflammatory markers interleukin-10 (1.53-fold) and tumour necrosis factor-alpha (1.61-fold) relative to controls. Conclusion. The protein-doped surface showed higher gene expression of typical genes involved in the osseointegration cascade than the control surface.

The primary stability of dental implants has been investigated before, but a study of the influence of implant shape, size and surface morphology (machined, acid etched or anodized), surgical technique (press-fit or undersized) and substrate (natural or simulated bone) on the primary stability of dental implants has not been reported. The present work intends to fill this gap. In this work, six different dental implants were inserted into and removed from synthetic and natural bone while measuring the torque. A total of 255 dental implants with three shapes, four sizes and three surface topographies were inserted into pig rib, PTFE and polyurethane. The implant sites were prepared using straight and tapered drills. The primary stability was estimated from the maximum insertion torque. Comparisons between samples were based on the maximum insertion torque (MIT), the maximum removal torque (MRT) and the torque ratio (TR=MRT/MIT). The insertion torque into pig ribs showed larger dispersion. All parameters (shape, size and surface morphology of the implant, surgical technique and substrate type) were found to have a significant influence on primary stability. The insertion of a tapered implant requires a higher torque than the insertion of a straight implant. Surface treatments improve the primary stability. The influence of the surgical technique is smaller than that of implant size and shape. The highest insertion torque was that of anodized tapered implants inserted into undersized sites. Finally, the primary stability of dental implants is highly dependent on implant design, surgical technique and substrate type.

Background: Nipple-sparing mastectomy (NSM) has gained popularity, but remains contoversial as the procedure's reconstructive outcomes and oncologic safety are still somewhat uncertain. Methods: We retrospectively reviewed the New York University-Langone Medical Center experience with NSM from 2006-2011. Outcomes measured include post-operative complications, breast cancer recurrence, presence of cancer at the nipple-areolar complex, and nipple-areolar complex viability. Results: Our data include patients who underwent NSM from 2006-2011. In total, the records of 235 (145 prophylactic, 90 theraputic) NSM at NYULMC were reviewed. Our reconstructive dta included all forms of reconstruction, including 144 tissue expanders, 74 microvascular free flaps, 16 immediate implants, and 1 combination latissimus dorsi flap with implant. Mean follow-up time was 19 months. No differences existed between the theraputic and prophylactic breast patients. The major complication rate of 4.3% (10/235) included 4 intraoperative hematoma evacuations, 1 flap anastomosis revision, and 3 explanted implants. One patient expired 4 months following surgery secondary to progression of disease. The microvascular free flap loss rate for this group was 0. Minor complications in 6.8% of patients consisted of implant exchange for asymmetry, operative revision of partial flap necrosis, intravenous antibiotics for infection, and 1 non-operative hematoma. In total, 5.9% of nipples were resected due to malignant or premalignant disease. There were 3 positive intraoperative biopsies with 9 additional biopsies positive on final pathology. To date, there have been no recurrences involving the nipple-areolar complex. The viability rate for the remaining nipples was 93.2% with1.7% of nipples undergoing complete necrosis, 3.8% partial necrosis, and 1.3% undergoing epiderolysis. Conclusions: This experience with NSM demonstrates the in a carefully selected cohort, oncologic safety and reconstructive outcome are comparable to the current st!

Background: Advances in breast cancer screening and treatment have fostered the use of surgical procedures that increasingly optimize cosmetic outcome, while ensuring oncologic safety remains the primary concern of the oncologic surgeon. The role of nipple-sparing mastectomy (NSM) for risk-reducing surgery and breast cancer is evolving. It can be difficult to demonstrate involvement of the nipple-areolar complex (NAC) preoperatively, and and in this report we examine the utility of intraoperative subareolar frozen section (FS). Methods: Records of patients undergoing NSM at the NYU Langone Medical Center from 2006-2011 were reviewed retrospectively. Use of subareolar FS was at surgeon's discretion. Results: 237 NSM were performed (146 prophylacytic, 91 theraputic). FC was not utilized in 58 mastectomies (28 prophylactic), with 2 (+) on paraffin. Among the remaining 180 mastectomies, 11 biopsies were (+)(7.2%); 5 subareolar biopsies were (+) on FS and paraffin histologic slides (PS)(2.8%); 6 were negative on FS and (+) on PS. Among the 3 prophylactic NSM with (+) subareolar biopsies there was 1 (+) FS, 1 (-) FS, and 1 with no FS performed. There were no false (+) FS. Four of the 5 patients with (+)FS underwent simultaneous excision of the NAC. The 5th patient had atypia on FS and DCIS on PS, and returned to the OR during the same hospitalization for removal of NAC. The remaining patients underwent subsequent excision of the NAC either during planned 2nd stage reconstruction or following completion of chemotherapy. 8 NAC were free of disease and 5 were positive for in situ or invasive disease. There has been no local recurrence in these patients to date. Conclusions: The rate of NAC involvement is low, 5.5% in this series, and FS, while utilized in the majority of these cases, detected only 46% of subareolar disease. While FS can direct intraoperative decision making, the predictive power is low, and these considerations must be addressed in preoperative patient discussions. Furthermore, among th!