Faculty Bibliography

BACKGROUND: Implementation science holds promise for better ensuring that research is translated into evidence-based policy and practice, but interventions often fail or even worsen the problems they are intended to solve due to a lack of understanding of real world structures and dynamic complexity. While systems science alone cannot possibly solve the major challenges in public health, systems-based approaches may contribute to changing the language and methods for conceptualising and acting within complex systems. The overarching goal of this paper is to improve the modelling used in dissemination and implementation research by applying best principles of systems science. DISCUSSION: Best principles, as distinct from the more customary term 'best practices', are used to underscore the need to extract the core issues from the context in which they are embedded in order to better ensure that they are transferable across settings. Toward meaningfully grappling with the complex and challenging problems faced in adopting and integrating evidence-based health interventions and changing practice patterns within specific settings, we propose and illustrate four best principles derived from our systems science experience: (1) model the problem, not the system; (2) pay attention to what is important, not just what is quantifiable; (3) leverage the utility of models as boundary objects; and (4) adopt a portfolio approach to model building. To improve our mental models of the real world, system scientists have created methodologies such as system dynamics, agent-based modelling, geographic information science and social network simulation. To understand dynamic complexity, we need the ability to simulate. Otherwise, our understanding will be limited. The practice of dynamic systems modelling, as discussed herein, is the art and science of linking system structure to behaviour for the purpose of changing structure to improve behaviour. A useful computer model creates a knowledge repository and a virtual library for internally consistent exploration of alternative assumptions. CONCLUSION: Among the benefits of systems modelling are iterative practice, participatory potential and possibility thinking. We trust that the best principles proposed here will resonate with implementation scientists; applying them to the modelling process may abet the translation of research into effective policy and practice.

BACKGROUND: We present an outcomes analysis of the surgical treatment of Robin sequence including all infants and comorbid conditions treated by tongue-lip adhesion (TLA) or mandibular distraction osteogenesis (MDO). METHODS: A 19-year single-institution, multisurgeon retrospective review of all syndromic and nonsyndromic neonates with Robin sequence treated with TLA (1994-2004) or MDO (2004-2013) was performed. Comorbid conditions were recorded in all patients. Outcomes include incidence of tracheostomy, improvement in obstructive breathing, and surgical complications. Need for repeat distraction and conversion from TLA to MDO were included as secondary end-points. Polysomnography data were recorded preoperatively at 1 month and 1 year as a measure of airway improvement. RESULTS: Seventy-four MDO patients and 15 TLA patients during the study period met inclusion criteria. There was no significant difference in mean age at intervention (32.1 +/- 29.0 vs 35.5 +/- 32.1 days), birth weight (2.9 +/- 0.7 vs 3.2 +/- 0.6 kg), prematurity (23.0 vs 35.7%), or intrauterine growth restriction (31.1 vs 15.4%). Central nervous system anomalies (24.3% vs 0.0%; P < 0.04) and gastrostomy tubes (66.2% vs 33.3%; P < 0.03) were present more frequently in MDO patients versus TLA patients. Rates of other organ system anomalies were similar between the groups. The success rate was significantly higher in the MDO group (90.5% vs 60.0%; P < 0.008). Postoperative tracheostomies occurred in 8.1% of the MDO group and 33.3% of the TLA group (P < 0.02). Preoperative apnea-hyponea index was similar between the two groups (38.3 vs 38.1). The apnea-hyponea index was significantly improved in the MDO group at 1 month (4.0 vs 21.7; P < 0.002) and 1 year (5.7 vs 20.5; P < 0.005). Surgical complications were statistically less in the MDO group (20.3 vs 53.3%; P < 0.02). CONCLUSIONS: In the heterogeneous population of Robin sequence, MDO demonstrates superior outcomes measures at 1 month and 1 year compared to TLA. Fewer complications occurred in the MDO group compared to the TLA.

This study evaluated the probability of survival (reliability) of platform-switched fixed dental prostheses (FDPs) cemented on different implant-abutment connection designs. Eighty-four-three-unit FDPs (molar pontic) were cemented on abutments connected to two implants of external or internal hexagon connection. Four groups (n = 21 each) were established: external hexagon connection and regular platform (ERC); external hexagon connection and switched platform (ESC); internal hexagon and regular platform (IRC); and internal hexagon and switched platform (ISC). Prostheses were subjected to step-stress accelerated life testing in water. Weibull curves and probability of survival for a mission of 100,000 cycles at 400 N (two-sided 90% CI) were calculated. The beta values of 0.22, 0.48, 0.50, and 1.25 for groups ERC, ESC, IRC, and ISC, respectively, indicated a limited role of fatigue in damage accumulation, except for group ISC. Survival decreased for both platform-switched groups (ESC: 74%, and ISC: 59%) compared with the regular matching platform counterparts (ERC: 95%, and IRC: 98%). Characteristic strength was higher only for ERC compared with ESC, but not different between internal connections. Failures chiefly involved the abutment screw. Platform switching decreased the probability of survival of FDPs on both external and internal connections. The absence in loss of characteristic strength observed in internal hexagon connections favor their use compared with platform-switched external hexagon connections.

PURPOSE: To evaluate the bone response to grade IV commercially pure titanium (G4) relative to Ti-6Al-4V (G5). MATERIALS AND METHODS: Implant surface topography was characterized by optical interferometry and scanning electron microscopy (SEM). Thirty-six implants (Signo Vinces, n = 18 per group) were installed in the radius of 18 dogs. The animals were killed at 1, 3, and 6 weeks, resulting in 6 implants per group and time in vivo for bone morphology, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) evaluation. RESULTS: SEM depicted a more uniform topography of G4 than G5. Surfaces were statistically homogeneous for Sa, Sq, and Sdr. At 1 week, new bone formation was observed within the healing connective tissue in contact with the implant surface. At 3 weeks, new bone in direct contact with the implant surface was observed at all bone regions. At 6 weeks, the healing chambers filled with woven bone depicted an onset of replacement by lamellar bone. No significant effect of substrate was detected. Time presented an effect on BIC and BAFO (P < 0.001). CONCLUSION: Both titanium substrates were biocompatible and osseoconductive at the bone tissue level.

Contemporary plastic surgery residents are increasingly challenged to learn a greater number of complex surgical techniques within a limited period. Surgical simulation and digital education resources have the potential to address some limitations of the traditional training model, and have been shown to accelerate knowledge and skills acquisition. Although animal, cadaver, and bench models are widely used for skills and procedure-specific training, digital simulation has not been fully embraced within plastic surgery. Digital educational resources may play a future role in a multistage strategy for skills and procedures training. The authors present two virtual surgical simulators addressing procedural cognition for cleft repair and craniofacial surgery. Furthermore, the authors describe how partnerships among surgical educators, industry, and philanthropy can be a successful strategy for the development and maintenance of digital simulators and educational resources relevant to plastic surgery training. It is our responsibility as surgical educators not only to create these resources, but to demonstrate their utility for enhanced trainee knowledge and technical skills development. Currently available digital resources should be evaluated in partnership with plastic surgery educational societies to guide trainees and practitioners toward effective digital content.

BACKGROUND: Implant-based breast reconstruction with an acellular dermal matrix is one of the most common procedures performed by plastic surgeons. Although numerous matrices are available, there is little literature comparing them. This study compares the rates of complications between two commonly used products: AlloDerm (human cadaveric) and SurgiMend (fetal bovine) acellular dermal matrices. METHODS: A retrospective review of a single center's 6-year experience was performed for consecutive, immediate breast reconstructions with acellular dermal matrix from 2009 to 2014. The authors compared demographics and surgical characteristics between patients receiving AlloDerm versus SurgiMend. Multivariate logistic regression was used to determine any association between type of matrix and surgical complications and to identify other clinical predictors for complications. RESULTS: A total of 640 patients underwent 952 reconstructions using AlloDerm [578 breasts (61 percent)] or SurgiMend [374 breasts (39 percent)]. The average follow-up was 587 days. Multivariate analysis revealed that type of matrix was not an independent risk factor for the development of complications. However, smoking, age, radiotherapy, and initial tissue expander fill volume were associated with increased risk of postoperative complications. CONCLUSIONS: Both AlloDerm and SurgiMend acellular dermal matrices demonstrate similar rates of major complications when used in immediate implant-based breast reconstruction. In contrast, preoperative radiation therapy, smoking, increasing age, and initial tissue expander fill volume are independent risk factors for postoperative complications. Reconstructive surgeons should take these findings into consideration when performing implant-based breast reconstruction with a dermal matrix.