Faculty Bibliography

INTRODUCTION: Obesity is a major cause of morbidity and mortality resulting in pathologic changes in virtually every organ system. Although the cardiovascular system has been a focus of intense study, the effects of obesity on the lymphatic system remain essentially unknown. The purpose of this study was to identify the pathologic consequences of diet induced obesity (DIO) on the lymphatic system. METHODS: Adult male wild-type or RAG C57B6-6J mice were fed a high fat (60%) or normal chow diet for 8-10 weeks followed by analysis of lymphatic transport capacity. In addition, we assessed migration of dendritic cells (DCs) to local lymph nodes, lymph node architecture, and lymph node cellular make up. RESULTS: High fat diet resulted in obesity in both wild-type and RAG mice and significantly impaired lymphatic fluid transport and lymph node uptake; interestingly, obese wild-type but not obese RAG mice had significantly impaired migration of DCs to the peripheral lymph nodes. Obesity also resulted in significant changes in the macro and microscopic anatomy of lymph nodes as reflected by a marked decrease in size of inguinal lymph nodes (3.4-fold), decreased number of lymph node lymphatics (1.6-fold), loss of follicular pattern of B cells, and dysregulation of CCL21 expression gradients. Finally, obesity resulted in a significant decrease in the number of lymph node T cells and increased number of B cells and macrophages. CONCLUSIONS: Obesity has significant negative effects on lymphatic transport, DC cell migration, and lymph node architecture. Loss of T and B cell inflammatory reactions does not protect from impaired lymphatic fluid transport but preserves DC migration capacity. Future studies are needed to determine how the interplay between diet, obesity, and the lymphatic system modulate systemic complications of obesity.

Lymphedema is a dreaded complication of cancer treatment. However, despite the fact that >5 million Americans are affected by this disorder, the development of effective treatments is limited by the fact that the pathology of lymphedema remains unknown. The purpose of these studies was to determine the role of inflammatory responses in lymphedema pathology. Using mouse models of lymphedema, as well as clinical lymphedema specimens, we show that lymphatic stasis results in a CD4 T-cell inflammation and T-helper 2 (Th2) differentiation. Using mice deficient in T cells or CD4 cells, we show that this inflammatory response is necessary for the pathological changes of lymphedema, including fibrosis, adipose deposition, and lymphatic dysfunction. Further, we show that inhibition of Th2 differentiation using interleukin-4 (IL-4) or IL-13 blockade prevents initiation and progression of lymphedema by decreasing tissue fibrosis and significantly improving lymphatic function, independent of lymphangiogenic growth factors. We show that CD4 inflammation is a critical regulator of tissue fibrosis and lymphatic dysfunction in lymphedema and that inhibition of Th2 differentiation markedly improves lymphatic function independent of lymphangiogenic cytokine expression. Notably, preventing and/or reversing the development of pathological tissue changes that occur in lymphedema may be a viable treatment strategy for this disorder.

BACKGROUND: Autologous breast reconstruction offers higher rates of patient satisfaction, but not all patients are ideal candidates, often due to inadequate volume of donor sites. Although autologous fat grafting is frequently used to augment volume and contour abnormalities in implant-based breast reconstruction, its clear utility in microsurgical breast reconstruction has yet to be defined. Here, we examined patients undergoing autologous microsurgical breast reconstruction with and without the adjunct of autologous fat grafting to clearly define utility and indications for use. METHODS: A retrospective review of all patients undergoing autologous breast reconstruction with microvascular free flaps at a single institution between November 2007 and October 2011 was conducted. Patients were divided into 2 groups as follows: those requiring postoperative fat grafting and those not requiring fat grafting. Patient demographics, indications for surgery, history of radiation therapy, patient body mass index, mastectomy specimen weight, need for rib resection, flap weight, and complications were analyzed in comparison. RESULTS: Two hundred twenty-eight patients underwent 374 microvascular free flaps for breast reconstruction. One hundred (26.7%) reconstructed breasts underwent postoperative fat grafting, with an average of 1.12 operative sessions. Fat was most commonly injected in the medial and superior medial poles of the breast and the average volume injected was 147.8 mL per breast (22-564 mL). The average ratio of fat injected to initial flap weight was 0.59 (0.07-1.39). Patients undergoing fat grafting were more likely to have had deep inferior epigastric perforator and profunda artery perforator flaps as compared to muscle-sparing transverse rectus abdominis myocutaneous. Patients additionally were more likely to have a prophylactic indication 58% (n = 58) versus 42% (n = 117) (P = 0.0087), rib resection 68% (n = 68) versus 54% (n = 148) (P < 0.0153), and acute postoperative complications requiring operative intervention 7% (n = 7) versus 2.1% (n = 8) (P < 0.0480). Additionally, patients undergoing autologous fat grafting had smaller body mass index, mastectomy weight, and flap weight. CONCLUSIONS: Fat grafting is most commonly used in those breasts with rib harvest, deep inferior epigastric perforator flap reconstructions, and those with acute postoperative complications. It should be considered a powerful adjunct to improve aesthetic outcomes in volume-deficient autologous breast reconstructions and additionally optimize contour in volume-adequate breast reconstructions.

OBJECTIVES/HYPOTHESIS: To characterize the anatomic distribution of lymphatic malformations of the upper airway. STUDY DESIGN: Case series with chart review. SETTING: Tertiary care referral center specializing in the diagnosis and treatment of vascular anomalies. METHODS: A 7-year (2004-2011) retrospective chart review of patients with lymphatic malformations was performed at a tertiary care referral center. Patients with airway lymphatic malformations were identified. The anatomic distribution of lymphatic malformations within the airway was reviewed. RESULTS: A total of 141 patients with lymphatic malformations of the upper aerodigestive tract (UADT) were studied. Of these, 15 (11%) had laryngeal (supraglottic) involvement. In all of these patients, the disease was above the true vocal folds. Seventy-four (52%) patients had involvement of 1 anatomic zone (most common was the oral cavity), and 67 (48%) had involvement of multiple zones. With regard to each zone, 105 (75%) patients had involvement of the oral cavity, 50 (36%) the oropharynx, 8 (6%) the hypopharynx, 42 (30%) the parapharynx, and 12 (9%) had retropharygeal disease (some patients had multiple zones involved). No patients were identified with glottic, subglottic, or tracheal involvement. CONCLUSIONS: Based on our large series, airway involvement in head and neck lymphatic malformations may occur at multiple sites above the glottis. A high percentage of these patients have involvement of the oral cavity (75%) and oropharynx (35%). None involve the glottis, subglottis, or trachea.

In both developed and developing countries, population aging has attained unprecedented levels. Public health strategies to deliver services in community-based settings are key to enhancing the utilization of preventive care and reducing costs for this segment of the population. Motivated by concerns of inadequate access to oral health care by older adults in urban environments, this article presents a portfolio of systems science models that have been developed on the basis of observations from the ElderSmile preventive screening program operated in northern Manhattan, New York City, by the Columbia University College of Dental Medicine. Using the methodology of system dynamics, models are developed to explore how interpersonal relationships influence older adults' participation in oral health promotion. Feedback mechanisms involving word of mouth about preventive screening opportunities are represented in relation to stocks that change continuously via flows, as well as agents whose states of health care utilization change discretely using stochastic transitions. Agent-based implementations illustrate how social networks and geographic information systems are integrated into dynamic models to reflect heterogeneous and proximity-based patterns of communication and participation in the ElderSmile program. The systems science approach builds shared knowledge among an interdisciplinary research team about the dynamics of access to opportunities for oral health promotion. Using "what if" scenarios to model the effects of program enhancements and policy changes, resources may be effectively leveraged to improve access to preventive and treatment services. Furthermore, since oral health and general health are inextricably linked, the integration of services may improve outcomes and lower costs.

BACKGROUND: Autologous microvascular breast reconstruction is an increasingly common procedure. While arterial anastomoses are traditionally being hand-sewn, venous anastomoses are often completed with a coupler device. The largest coupler size possible should be used, as determined by the smaller of either the donor or recipient vein. While its efficacy has been shown using 3.0-mm size and greater couplers, little is known about the consequences of using coupler sizes less than or equal to 2.5 mm. Methods: A retrospective chart review of patients undergoing autologous breast reconstruction was conducted at NYU Medical Center between November 2007 and November 2011. Flaps were divided into cohorts based on coupler size used: 2.0 mm, 2.5 mm, and 3.0 mm. Outcomes included incidence of arterial or venous insufficiency, hematoma, fat necrosis, partial flap loss, full flap loss, and need for future fat grafting. Results: One-hundred ninety-seven patients underwent 392 flaps during the study period. Patients were similar in age, type of flap, smoking status, and radiation history. Coupler size less than or equal to 2.0 mm was found to be a significant risk factor for venous insufficiency (P = 0.038), as well as for development of fat necrosis (P = 0.041) and future need for fat grafting (P = 0.050). In multivariate analysis, body mass index was found to be an independent risk factor for skin flap necrosis (P = 0.010) and full flap loss (P = 0.035). Conclusions: Complications were significantly increased in patients where couplers of 2.0 mm or less were used, therefore to be avoided whenever possible. When needed, more aggressive vessel exposure through rib harvest, the use of thoracodorsal vessels or hand-sewing the anastomosis should be considered in cases of internal mammary vein caliber of 2.0 mm or less. CLINICAL QUESTION: Therapeutic LEVEL OF EVIDENCE: Level III. (c) 2013 Wiley Periodicals, Inc. Microsurgery, 2013.

A patient with a severe case of Poland syndrome presented with a painful capsular contracture from a previous implant-based breast reconstruction. She desired the implant to be removed and to proceed with autologous reconstruction, sizeable enough to match the volume of her contralateral breast. A paucity of abdominal donor tissue combined with the patient's hesitancy to acquire an anterior scar excluded this location as a free tissue transfer option. As an alternative donor site, the profunda artery perforator (PAP) flap was chosen. Bilateral PAP flaps were harvested and stacked using anterograde and retrograde anastomoses to the internal mammary vessels. Enough volume was present to fill her chest wall concavity and provide adequate projection to achieve symmetry with her contralateral breast. Her donor sites healed well and remained inconspicuous, without generating difficulties sitting. In conclusion, stacked PAP flaps provide an excellent alternative to an abdominal donor site for achieving large volume unilateral breast reconstruction.

Bioglasses are considered osteoconductive and osteoproductive biomaterials and some types also exhibit angiogenic, bacteriostatic and anti-inflammatory properties. Despite these facts, bioglasses have only a few commercial applications, mainly because they do not exhibit as good mechanical properties as titanium. This study evaluated the biological performance of titanium implants coated with a highly bioactive glass. The experimental study was performed in vivo and in vitro. The in vitro study was conducted by evaluating the adhesion and cell viability on titanium disks treated with highly bioactive glass. For the in vivo study, implants were installed in the mandibles of dogs Beagles. A group of implants presented a surface with double acid-etched and the other group had a surface with double acid-etched + highly bioactive glass. The results confirmed that coating pattern tested in this study is non cytotoxic and does not adversely affect the new bone formation on the implant interface, showing performance comparable to that of physically modified surface with double acid-etched. The results of this research do not demonstrated a significant increase in bone formation after the incorporation of bioactive glass on titanium surfaces, but indicates the possibility of modifying titanium surfaces in a predicable and promisingway