Axonal Tract Reconstruction Using a Tissue-Engineered Nigrostriatal Pathway in a Rat Model of Parkinson's Disease.

Parkinson's disease (PD) affects 1-2% of people over 65, causing significant morbidity across a progressive disease course. The classic PD motor deficits are caused by the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc), resulting in the loss of their long-distance axonal projections that modulate striatal output. While contemporary treatments temporarily alleviate symptoms of this disconnection, there is no approach able to replace the nigrostriatal pathway. We applied microtissue engineering techniques to create a living, implantable tissue-engineered nigrostriatal pathway (TE-NSP) that mimics the architecture and function of the native pathway. TE-NSPs comprise a discrete population of dopaminergic neurons extending long, bundled axonal tracts within the lumen of hydrogel micro-columns. Neurons were isolated from the ventral mesencephalon of transgenic rats selectively expressing the green fluorescent protein in dopaminergic neurons with subsequent fluorescent-activated cell sorting to enrich a population to 60% purity. The lumen extracellular matrix and growth factors were varied to optimize cytoarchitecture and neurite length, while immunocytochemistry and fast-scan cyclic voltammetry (FSCV) revealed that TE-NSP axons released dopamine and integrated with striatal neurons in vitro. Finally, TE-NSPs were implanted to span the nigrostriatal pathway in a rat PD model with a unilateral 6-hydroxydopamine SNpc lesion. Immunohistochemistry and FSCV established that transplanted TE-NSPs survived, maintained their axonal tract projections, extended dopaminergic neurites into host tissue, and released dopamine in the striatum. This work showed proof of concept that TE-NSPs can reconstruct the nigrostriatal pathway, providing motivation for future studies evaluating potential functional benefits and long-term durability of this strategy. This pathway reconstruction strategy may ultimately replace lost neuroarchitecture and alleviate the cause of motor symptoms for PD patients.

Tissue-engineered grafts exploit axon-facilitated axon regeneration and pathway protection to enable recovery after 5-cm nerve defects in pigs.

Functional restoration following major peripheral nerve injury (PNI) is challenging, given slow axon growth rates and eventual regenerative pathway degradation in the absence of axons. We are developing tissue-engineered nerve grafts (TENGs) to simultaneously "bridge" missing nerve segments and "babysit" regenerative capacity by providing living axons to guide host axons and maintain the distal pathway. TENGs were biofabricated using porcine neurons and "stretch-grown" axon tracts. TENG neurons survived and elicited axon-facilitated axon regeneration to accelerate regrowth across both short (1 cm) and long (5 cm) segmental nerve defects in pigs. TENG axons also closely interacted with host Schwann cells to maintain proregenerative capacity. TENGs drove regeneration across 5-cm defects in both motor and mixed motor-sensory nerves, resulting in dense axon regeneration and electrophysiological recovery at levels similar to autograft repairs. This approach of accelerating axon regeneration while maintaining the pathway for long-distance regeneration may achieve recovery after currently unrepairable PNIs.

Pharmacokinetic and Pharmacological Aspects of a Papain-Based Enzyme Solution for Rescuing Clogged Enteral Feeding Tubes.

Successful enteral feeding depends on patent enteral feeding tubes to permit trouble-free entry of nutritional formula into the alimentary tract. However, tube clogs can be a challenging complication of enteral feeding. This report addresses questions about using a papain-based enzyme solution to unclog enteral feeding tubes, including any effects that papain may have on patients and if solution use should be contraindicated in patients on ketogenic diets. The gastrointestinal tract is not permissive for significant papain activity and papain absorbed into the blood would likely be neutralized by antiproteases. In vitro examinations do not suggest toxic effects of papain in vivo, and those recognized in the latter setting are due to papain loads that exceed those used to unclog enteral feeding tubes. Allergies to papain occur infrequently and are probably attributable to an immunoglobulin E-mediated reaction to this enzyme. Although the amount of carbohydrate consumed upon single use of the unclogging solution is very low, a provider should decide whether using the papain-based enzyme solution for enteral feeding purposes is appropriate in patients who practice ketogenic diets. The benefits of using the papain-based enzyme solution to unclog enteral feeding tubes appear to outweigh any risks associated with its use.

Tyrosine-derived polycarbonate nerve guidance tubes elicit proregenerative extracellular matrix deposition when used to bridge segmental nerve defects in swine.

Promising biomaterials should be tested in appropriate large animal models that recapitulate human inflammatory and regenerative responses. Previous studies have shown tyrosine-derived polycarbonates (TyrPC) are versatile biomaterials with a wide range of applications across multiple disciplines. The library of TyrPC has been well studied and consists of thousands of polymer compositions with tunable mechanical characteristics and degradation and resorption rates that are useful for nerve guidance tubes (NGTs). NGTs made of different TyrPCs have been used in segmental nerve defect models in small animals. The current study is an extension of this work and evaluates NGTs made using two different TyrPC compositions in a 1 cm porcine peripheral nerve repair model. We first evaluated a nondegradable TyrPC formulation, demonstrating proof-of-concept chronic regenerative efficacy up to 6 months with similar nerve/muscle electrophysiology and morphometry to the autograft repair control. Next, we characterized the acute regenerative response using a degradable TyrPC formulation. After 2 weeks in vivo, TyrPC NGT promoted greater deposition of pro-regenerative extracellular matrix (ECM) constituents (in particular collagen I, collagen III, collagen IV, laminin, and fibronectin) compared to commercially available collagen-based NGTs. This corresponded with dense Schwann cell infiltration and axon extension across the lumen. These findings confirmed results reported previously in a mouse model and reveal that TyrPC NGTs were well tolerated in swine and facilitated host axon regeneration and Schwann cell infiltration in the acute phase across segmental defects - likely by eliciting a favorable neurotrophic ECM milieu. This regenerative response ultimately can contribute to functional recovery.

Tissue engineered axon-based "living scaffolds" promote survival of spinal cord motor neurons following peripheral nerve repair.

Peripheral nerve injury (PNI) impacts millions annually, often leaving debilitated patients with minimal repair options to improve functional recovery. Our group has previously developed tissue engineered nerve grafts (TENGs) featuring long, aligned axonal tracts from dorsal root ganglia (DRG) neurons that are fabricated in custom bioreactors using the process of axon "stretch-growth." We have shown that TENGs effectively serve as "living scaffolds" to promote regeneration across segmental nerve defects by exploiting the newfound mechanism of axon-facilitated axon regeneration, or "AFAR," by simultaneously providing haptic and neurotrophic support. To extend this work, the current study investigated the efficacy of living versus nonliving regenerative scaffolds in preserving host sensory and motor neuronal health following nerve repair. Rats were assigned across five groups: naïve, or repair using autograft, nerve guidance tube (NGT) with collagen, NGT + non-aligned DRG populations in collagen, or TENGs. We found that TENG repairs yielded equivalent regenerative capacity as autograft repairs based on preserved health of host spinal cord motor neurons and acute axonal regeneration, whereas NGT repairs or DRG neurons within an NGT exhibited reduced motor neuron preservation and diminished regenerative capacity. These acute regenerative benefits ultimately resulted in enhanced levels of functional recovery in animals receiving TENGs, at levels matching those attained by autografts. Our findings indicate that TENGs may preserve host spinal cord motor neuron health and regenerative capacity without sacrificing an otherwise uninjured nerve (as in the case of the autograft) and therefore represent a promising alternative strategy for neurosurgical repair following PNI.

Management of adult patients with type 1 diabetes mellitus in Africa: A post-hoc cohort analysis of 12 African countries participating in the International Diabetes Management Practices Study (Wave 7).

There is a paucity of information on real world management of African adult patients with type 1 diabetes mellitus (T1DM). We aimed to describe a cohort of African adults with T1DM.The International Diabetes Management Practices Study is an observational survey conducted from 2005 to 2017. Data were collected in seven individual waves from countries in Asia, Africa, East Europe, and Latin America. Wave 7 was conducted from 2016 to 2017 and the African cohort included 12 countries. Questionnaires were administered to clinicians and patients. Analyses were mainly descriptive. Logistic regressions were performed to identify predictive factors for glycaemic control.A total of 788 patients were enrolled in the study. HbA1c values were available for 712 patients; only 16.6% had HbA1c values <7%. A total of 196 (24.9%) reported being hospitalized in the preceding year, with the most common reasons being diabetic ketoacidosis (58.1%, 93/160) and hypoglycaemia (31.1%; 52/167). Over half of the patients (55.4%) stated that the cost of test strips limited regular glycemic monitoring; a minority of patients (15%, 120/788) received structured diabetes education. Predictors of HbA1c <7% included patients receiving diabetes education (odds ratio [OR] [95% confidence interval, CI] = 2.707 [1.157-6.335] P = .022), following a healthy diet and exercise plan (OR [95% CI] = 2.253 [1.206-4.209], P < .001) and self-managing (monitoring glucose levels and adjusting insulin accordingly) (OR [95% CI] 2.508 [1.500-4.191] P < .001).African adults with T1DM have suboptimal glycemic control with almost one-quarter reporting hospitalization within the preceding year. Most patients felt comfortable with self-adjustment of insulin dose but said that the cost of test strips was the main factor that limited regular monitoring. Reducing direct costs of testing strips and insulin, and improving education will address major challenges within these settings.

A Porcine Model of Peripheral Nerve Injury Enabling Ultra-Long Regenerative Distances: Surgical Approach, Recovery Kinetics, and Clinical Relevance.

BACKGROUND: Millions of Americans experience residual deficits from traumatic peripheral nerve injury (PNI). Despite advancements in surgical technique, repair typically results in poor functional outcomes due to prolonged periods of denervation resulting from long regenerative distances coupled with slow rates of axonal regeneration. Novel surgical solutions require valid preclinical models that adequately replicate the key challenges of clinical PNI. OBJECTIVE: To develop a preclinical model of PNI in swine that addresses 2 challenging, clinically relevant PNI scenarios: long segmental defects (≥5 cm) and ultra-long regenerative distances (20-27 cm). Thus, we aim to demonstrate that a porcine model of major PNI is suitable as a potential framework to evaluate novel regenerative strategies prior to clinical deployment. METHODS: A 5-cm-long common peroneal nerve or deep peroneal nerve injury was repaired using a saphenous nerve or sural nerve autograft, respectively. Histological and electrophysiological assessments were performed at 9 to 12 mo post repair to evaluate nerve regeneration and functional recovery. Relevant anatomy, surgical approach, and functional/histological outcomes were characterized for both repair techniques. RESULTS: Axons regenerated across the repair zone and were identified in the distal stump. Electrophysiological recordings confirmed these findings and suggested regenerating axons reinnervated target muscles. CONCLUSION: The models presented herein provide opportunities to investigate peripheral nerve regeneration using different nerves tailored for specific mechanisms of interest, such as nerve modality (motor, sensory, and mixed fiber composition), injury length (short/long gap), and total regenerative distance (proximal/distal injury).

Incidence of hypoglycaemia in the South African population with diabetes: results from the IDMPS Wave 7 study

Objectives: Management of diabetes is a balancing act of preventing a state of hyperglycaemia while avoiding episodes of hypoglycaemia. Limited information is currently available on the incidence of hypoglycaemia in South African people diagnosed with diabetes. Data regarding the management of diabetes and incidence of hypoglycaemia in the South African population was collected as part of Wave 7 of the International Diabetes Management Practices Study (IDMPS). Design and methods: During this observational study the first 10 adult individuals with type 2 diabetes and the first five adult individuals with type 1 diabetes presenting to a study site during the two-week study period were enrolled. Setting:Patients were enrolled from the private healthcare sector in South Africa only. Subjects:A total of 445 individuals (49 diagnosed with T1D, 396 diagnosed with T2D) were included. Outcome measures:Glycated haemoglobin and hypoglycaemia data were recorded for each patient. Results:Of the patients who reported experiencing hypoglycaemia, 48.6% (17/35) among T1D individuals and 67.8% (40/71) among T2D individuals experienced hypoglycaemia over a four-week period. Furthermore, in patients who discontinued insulin treatment (n= 11), fear of hypoglycaemia was reported to influence adherence to insulin treatment by 27.3% in T1D and T2D individuals. Of the 148 patients not achieving their HbA1c target, 23.0% reported fear of hypoglycaemia as a reason. Conclusions: This report demonstrates the need to address hypoglycaemia and fear of hypoglycaemia in the South African diabetes population

Evaluating the in vivo glial response to miniaturized parylene cortical probes coated with an ultra-fast degrading polymer to aid insertion.

OBJECTIVE: Despite the feasibility of short-term neural recordings using implantable microelectrodes, attaining reliable, chronic recordings remains a challenge. Most neural recording devices suffer from a long-term tissue response, including gliosis, at the device-tissue interface. It was hypothesized that smaller, more flexible intracortical probes would limit gliosis by providing a better mechanical match with surrounding tissue. APPROACH: This paper describes the in vivo evaluation of flexible parylene microprobes designed to improve the interface with the adjacent neural tissue to limit gliosis and thereby allow for improved recording longevity. The probes were coated with an ultrafast degrading tyrosine-derived polycarbonate (E5005(2K)) polymer that provides temporary mechanical support for device implantation, yet degrades within 2 h post-implantation. A parametric study of probes of varying dimensions and polymer coating thicknesses were implanted in rat brains. The glial tissue response and neuronal loss were assessed from 72 h to 24 weeks post-implantation via immunohistochemistry. MAIN RESULTS: Experimental results suggest that both probe and polymer coating sizes affect the extent of gliosis. When an appropriate sized coating dimension (100 µm × 100 µm) and small probe (30 µm × 5 µm) was implanted, a minimal post-implantation glial response was observed. No discernible gliosis was detected when compared to tissue where a sham control consisting of a solid degradable polymer shuttle of the same dimensions was inserted. A larger polymer coating (200 µm × 200 µm) device induced a more severe glial response at later time points, suggesting that the initial insertion trauma can affect gliosis even when the polymer shuttle degrades rapidly. A larger degree of gliosis was also observed when comparing a larger sized probe (80 µm × 5 µm) to a smaller probe (30 µm × 5 µm) using the same polymer coating size (100 µm × 100 µm). There was no significant neuronal loss around the implantation sites for most device candidates except the group with largest polymer coating and probe sizes. SIGNIFICANCE: These results suggest that: (1) the degree of mechanical trauma at device implantation and mechanical mismatches at the probe-tissue interface affect long term gliosis; (2) smaller, more flexible probes may minimize the glial response to provide improved tissue biocompatibility when used for chronic neural signal recording; and (3) some degree of glial scarring did not significantly affect neuronal distribution around the probe.

Predoctoral and Postdoctoral Training Pipeline in Translational Biomaterials Research and Regenerative Medicine.

The translation of biomaterial based and regenerative therapies from the laboratory to patients involves multiple challenges. One of the most pressing challenges is the educational one: to train a cohort of scientists and engineers capable of translating their discoveries from bench to market to clinic. To meet this need, translational training programs are being implemented globally at universities and as partnerships between universities and corporations. In this perspective, we describe two translational NIH T32 graduate and postgraduate training programs that augment the traditional approach to training early stage scientists and engineers. At the graduate level, Boston University developed and implemented the Translational Research in Biomaterials (TRB) predoctoral training program. At the postgraduate level, Rutgers, The State University of New Jersey, developed and implemented the Translational Research in Regenerative Medicine (TRRM) program for postdoctoral training. These programs are motivated by the need for training in translational research in the biomedical field, by young scientists' requests for such training, and by the fundamental challenges facing future discovery and clinical implementation of biomaterial-based technologies. The TRB program immerses trainees in the concept of translating an idea from the research laboratory to the clinic, introduces them to the challenges of such an endeavor, provides discussions with relevant faculty (for example, with businesses, patient care, or clinical trial experience), and educates them in the critical areas required for their future careers. Similarly, the TRRM program emphasizes translational research and the concept of "training without borders," which enables collaborations across several geographically dispersed institutions so as to make regional experts accessible regardless of where they are located physically. Both programs promote interdisciplinary research, expose young scientists and engineers to challenges outside of their specialty, and build interpersonal skills for cross-disciplinary communication. The TRB program focuses on quantitative science and engineering courses, together with translation-based courses in clinical trials and business. The TRRM program focuses on broadening the horizon of its trainees through exposure to a wider network of mentors than traditional postdoctoral programs, and by encouraging trainees to engage in collaborative research across at least two different laboratories. Both programs meet significant public health needs: the skills that trainees acquire are essential in future biomedical careers as they join teams that combine diverse backgrounds to meet a common goal in research, development, and ultimately commercialization.

Dual-Component Gelatinous Peptide/Reactive Oligomer Formulations as Conduit Material and Luminal Filler for Peripheral Nerve Regeneration.

Toward the next generation of nerve guidance conduits (NGCs), novel biomaterials and functionalization concepts are required to address clinical demands in peripheral nerve regeneration (PNR). As a biological polymer with bioactive motifs, gelatinous peptides are promising building blocks. In combination with an anhydride-containing oligomer, a dual-component hydrogel system (cGEL) was established. First, hollow cGEL tubes were fabricated by a continuous dosing and templating process. Conduits were characterized concerning their mechanical strength, in vitro and in vivo degradation and biocompatibility. Second, cGEL was reformulated as injectable shear thinning filler for established NGCs, here tyrosine-derived polycarbonate-based braided conduits. Thereby, the formulation contained the small molecule LM11A-31. The biofunctionalized cGEL filler was assessed regarding building block integration, mechanical properties, in vitro cytotoxicity, and growth permissive effects on human adipose tissue-derived stem cells. A positive in vitro evaluation motivated further application of the filler material in a sciatic nerve defect. Compared to the empty conduit and pristine cGEL, the functionalization performed superior, though the autologous nerve graft remains the gold standard. In conclusion, LM11A-31 functionalized cGEL filler with extracellular matrix (ECM)-like characteristics and specific biochemical cues holds great potential to support PNR.

Fibrin glue as a stabilization strategy in peripheral nerve repair when using porous nerve guidance conduits.

Porous conduits provide a protected pathway for nerve regeneration, while still allowing exchange of nutrients and wastes. However, pore sizes >30 µm may permit fibrous tissue infiltration into the conduit, which may impede axonal regeneration. Coating the conduit with Fibrin Glue (FG) is one option for controlling the conduit's porosity. FG is extensively used in clinical peripheral nerve repair, as a tissue sealant, filler and drug-delivery matrix. Here, we compared the performance of FG to an alternative, hyaluronic acid (HA) as a coating for porous conduits, using uncoated porous conduits and reverse autografts as control groups. The uncoated conduit walls had pores with a diameter of 60 to 70 µm that were uniformly covered by either FG or HA coatings. In vitro, FG coatings degraded twice as fast as HA coatings. In vivo studies in a 1 cm rat sciatic nerve model showed FG coating resulted in poor axonal density (993 ± 854 #/mm2), negligible fascicular area (0.03 ± 0.04 mm2), minimal percent wet muscle mass recovery (16 ± 1 in gastrocnemius and 15 ± 5 in tibialis anterior) and G-ratio (0.73 ± 0.01). Histology of FG-coated conduits showed excessive fibrous tissue infiltration inside the lumen, and fibrin capsule formation around the conduit. Although FG has been shown to promote nerve regeneration in non-porous conduits, we found that as a coating for porous conduits in vivo, FG encourages scar tissue infiltration that impedes nerve regeneration. This is a significant finding considering the widespread use of FG in peripheral nerve repair.

Modeling the Insertion Mechanics of Flexible Neural Probes Coated with Sacrificial Polymers for Optimizing Probe Design.

Single-unit recording neural probes have significant advantages towards improving signal-to-noise ratio and specificity for signal acquisition in brain-to-computer interface devices. Long-term effectiveness is unfortunately limited by the chronic injury response, which has been linked to the mechanical mismatch between rigid probes and compliant brain tissue. Small, flexible microelectrodes may overcome this limitation, but insertion of these probes without buckling requires supporting elements such as a stiff coating with a biodegradable polymer. For these coated probes, there is a design trade-off between the potential for successful insertion into brain tissue and the degree of trauma generated by the insertion. The objective of this study was to develop and validate a finite element model (FEM) to simulate insertion of coated neural probes of varying dimensions and material properties into brain tissue. Simulations were performed to predict the buckling and insertion forces during insertion of coated probes into a tissue phantom with material properties of brain. The simulations were validated with parallel experimental studies where probes were inserted into agarose tissue phantom, ex vivo chick embryonic brain tissue, and ex vivo rat brain tissue. Experiments were performed with uncoated copper wire and both uncoated and coated SU-8 photoresist and Parylene C probes. Model predictions were found to strongly agree with experimental results (<10% error). The ratio of the predicted buckling force-to-predicted insertion force, where a value greater than one would ideally be expected to result in successful insertion, was plotted against the actual success rate from experiments. A sigmoidal relationship was observed, with a ratio of 1.35 corresponding to equal probability of insertion and failure, and a ratio of 3.5 corresponding to a 100% success rate. This ratio was dubbed the "safety factor", as it indicated the degree to which the coating should be over-designed to ensure successful insertion. Probability color maps were generated to visually compare the influence of design parameters. Statistical metrics derived from the color maps and multi-variable regression analysis confirmed that coating thickness and probe length were the most important features in influencing insertion potential. The model also revealed the effects of manufacturing flaws on insertion potential.

Nanoparticles and nanofibers for topical drug delivery.

This review provides the first comprehensive overview of the use of both nanoparticles and nanofibers for topical drug delivery. Researchers have explored the use of nanotechnology, specifically nanoparticles and nanofibers, as drug delivery systems for topical and transdermal applications. This approach employs increased drug concentration in the carrier, in order to increase drug flux into and through the skin. Both nanoparticles and nanofibers can be used to deliver hydrophobic and hydrophilic drugs and are capable of controlled release for a prolonged period of time. The examples presented provide significant evidence that this area of research has - and will continue to have - a profound impact on both clinical outcomes and the development of new products.

The overwhelming use of rat models in nerve regeneration research may compromise designs of nerve guidance conduits for humans.

Rats are not the best model for the evolving complexities we face in designing nerve repair strategies today. The development of effective nerve guidance conduits for nerve regeneration is severely limited by the rat sciatic nerve model as the almost exclusive research model in academia. An immense effort is underway to develop an alternative to autologous nerve grafts for the repair of nerve defects, aiming particularly at larger gap repairs of 5-30 cm or more. This must involve combinations of ever more complex components, which in the vast majority of cases begin their testing in the rat model. Three major problems are at play: (1) The majority of nerve regeneration data is now being generated in the rat, which is likely to skew treatment outcomes and lead to inappropriate evaluation of risks and benefits. (2) The rat is a particularly poor model for the repair of human critical gap defects due to both its small size and its species-specific neurobiological regenerative profile. (3) Translation from rat to human has proven unreliable for nerve regeneration, as for many other applications. We explore each of these facets and their implications, in order to highlight the need for appropriate awareness in animal model selection when translating nerve regeneration modalities of ever-increasing complexity-from relatively simple devices to drug-device-biologic combinations.

Coating flexible probes with an ultra fast degrading polymer to aid in tissue insertion.

We report a fabrication process for coating neural probes with an ultrafast degrading polymer to create consistent and reproducible devices for neural tissue insertion. The rigid polymer coating acts as a probe insertion aid, but resorbs within hours post-implantation. Despite the feasibility for short term neural recordings from currently available neural prosthetic devices, most of these devices suffer from long term gliosis, which isolates the probes from adjacent neurons, increasing the recording impedance and stimulation threshold. The size and stiffness of implanted probes have been identified as critical factors that lead to this long term gliosis. Smaller, more flexible probes that match the mechanical properties of brain tissue could allow better long term integration by limiting the mechanical disruption of the surrounding tissue during and after probe insertion, while being flexible enough to deform with the tissue during brain movement. However, these small flexible probes inherently lack the mechanical strength to penetrate the brain on their own. In this work, we have developed a micromolding method for coating a non-functional miniaturized SU-8 probe with an ultrafast degrading tyrosine-derived polycarbonate (E5005(2K)). Coated, non-functionalized probes of varying dimensions were reproducibly fabricated with high yields. The polymer erosion/degradation profiles of the probes were characterized in vitro. The probes were also mechanically characterized in ex vivo brain tissue models by measuring buckling and insertion forces during probe insertion. The results demonstrate the ability to produce polymer coated probes of consistent quality for future in vivo use, for example to study the effects of different design parameters that may affect tissue response during long term chronic intra-cortical microelectrode neural recordings.

Primary breast augmentation clinical trial outcomes stratified by surgical incision, anatomical placement and implant device type.

BACKGROUND: Clinical evidence concerning the potential risks and benefits associated with surgical incision, anatomical pocket and implant device type in primary breast augmentation is lacking. OBJECTIVES: This study assesses relative risk (RR) of adverse events stratified by surgical incision, anatomical pocket and breast implant device in primary augmentation patients enrolled in Core (NCT00689871, round/silicone devices) and 410 (NCT00690339, anatomically shaped/highly cohesive silicone devices) long-term clinical trials. METHODS: RR for time-to-first-event of Baker grade 3-4 capsular contracture (CC), moderate-severe malposition, and secondary procedure were calculated using multivariate time-to-event regression analysis. RESULTS: Risk of CC was increased with periareolar (unadjusted model only) and with axillary (adjusted model) versus inframammary incision. Risk of CC was significantly reduced with subpectoral versus subglandular placement (adjusted model), and with textured surface/round/silicone-filled devices and textured surface/shaped/highly cohesive silicone-filled devices versus smooth surface/round/silicone-filled devices (adjusted model). Risk of CC was significantly reduced with textured surface devices independent of subpectoral or subglandular placement (adjusted model). In a number-needed-to-treat analysis, 7-9 patients needed to be treated with a textured surface device to prevent one Baker grade 3-4 CC over 10 years. Risk of moderate-severe malposition was significantly increased with periareolar (adjusted model) and axillary (adjusted model) versus inframammary incision; and significantly lower with textured surface/shaped/highly cohesive silicone-filled devices than with smooth surface/round/silicone-filled devices (adjusted model). Risk of secondary procedures was significantly increased with periareolar (adjusted model) and axillary (adjusted model) versus inframammary incision; and significantly reduced with textured surface/shaped/highly cohesive silicone-filled devices versus smooth surface/round/silicone-filled devices (adjusted model). CONCLUSIONS: In primary breast augmentation, surgical incision, anatomical pocket, and device were significant predictors of clinical outcomes: capsular contracture, malposition and secondary procedure.