Sumanas W. Jordan

Three-Dimensional Printing of High-Content Graphene Scaffolds for Electronic and Biomedical Applications

The exceptional properties of graphene enable applications in electronics, optoelectronics, energy storage, and structural composites. Here we demonstrate a 3D printable graphene (3DG) composite consisting of majority graphene and minority polylactide-co-glycolide, a biocompatible elastomer, 3D-printed from a liquid ink. This ink can be utilized under ambient conditions via extrusion-based 3D printing to create graphene structures with features as small as 100 μm composed of as few as two layers (<300 μm thick object) or many hundreds of layers (>10 cm thick object). The resulting 3DG material is mechanically robust and flexible while retaining electrical conductivities greater than 800 S/m, an order of magnitude increase over previously reported 3D-printed carbon materials. In vitro experiments in simple growth medium, in the absence of neurogenic stimuli, reveal that 3DG supports human mesenchymal stem cell (hMSC) adhesion, viability, proliferation, and neurogenic differentiation with significant upregulation of glial and neuronal genes. This coincides with hMSCs adopting highly elongated morphologies with features similar to axons and presynaptic terminals. In vivo experiments indicate that 3DG has promising biocompatibility over the course of at least 30 days. Surgical tests using a human cadaver nerve model also illustrate that 3DG has exceptional handling characteristics and can be intraoperatively manipulated and applied to fine surgical procedures. With this unique set of properties, combined with ease of fabrication, 3DG could be applied toward the design and fabrication of a wide range of functional electronic, biological, and bioelectronic medical and nonmedical devices.

Hyperelastic “bone”: A highly versatile, growth factor–free, osteoregenerative, scalable, and surgically friendly biomaterial

A new, mechanically elastic biomaterial can be custom 3D-printed, is surgically friendly, and promotes robust bone regeneration. Building better bones What if we could create custom bone implants that would trigger their own replacement with real bone? Jakus and colleagues have done just this with a promising biomaterial that can be 3D-printed into many shapes and easily deployed in the operating room. Made mainly of hydroxyapatite and either polycaprolactone or poly(lactic-co-glycolic acid), this “hyperelastic bone” can be 3D-printed at up to 275 cm3/hour, the authors report. It also promoted bone growth in vitro, in mice and rats, and in a case study of skull repair in a rhesus macaque. Its effectiveness, fast, easy synthesis, and ease of use in surgery set it apart from many of the materials now available for bone repair. Despite substantial attention given to the development of osteoregenerative biomaterials, severe deficiencies remain in current products. These limitations include an inability to adequately, rapidly, and reproducibly regenerate new bone; high costs and limited manufacturing capacity; and lack of surgical ease of handling. To address these shortcomings, we generated a new, synthetic osteoregenerative biomaterial, hyperelastic “bone” (HB). HB, which is composed of 90 weight % (wt %) hydroxyapatite and 10 wt % polycaprolactone or poly(lactic-co-glycolic acid), could be rapidly three-dimensionally (3D) printed (up to 275 cm3/hour) from room temperature extruded liquid inks. The resulting 3D-printed HB exhibited elastic mechanical properties (~32 to 67% strain to failure, ~4 to 11 MPa elastic modulus), was highly absorbent (50% material porosity), supported cell viability and proliferation, and induced osteogenic differentiation of bone marrow–derived human mesenchymal stem cells cultured in vitro over 4 weeks without any osteo-inducing factors in the medium. We evaluated HB in vivo in a mouse subcutaneous implant model for material biocompatibility (7 and 35 days), in a rat posterolateral spinal fusion model for new bone formation (8 weeks), and in a large, non-human primate calvarial defect case study (4 weeks). HB did not elicit a negative immune response, became vascularized, quickly integrated with surrounding tissues, and rapidly ossified and supported new bone growth without the need for added biological factors.

Resident involvement and plastic surgery outcomes: an analysis of 10,356 patients from the American College of Surgeons National Surgical Quality Improvement Program database.

Background: Intraoperative experience is an essential component of surgical training. The impact of resident involvement in plastic surgery has not previously been studied on a large scale. Methods: The authors retrospectively reviewed the American College of Surgeons National Surgical Quality Improvement Program database from 2006 to 2010 for all reconstructive plastic surgery cases. Resident involvement was tracked as an individual variable to compare outcomes. Results: A total of 10,356 cases were identified, with 43 percent noted as having resident involvement. The average total relative value units, a proxy for surgical complexity, and operative time were higher for procedures with residents present. When balanced by baseline characteristics using propensity score stratification into quintiles, no differences in graft, prosthesis, or flap failure or mortality were observed. Furthermore, there were no differences in overall complications or wound infection with resident involvement for a majority of the quintiles. Multivariable logistic regression analysis revealed that resident involvement was a significant predictor of overall morbidity, but not associated with increased odds of wound infection, graft, prosthesis or flap failure, or overall mortality. Conclusions: Residency has the dual mission of training future physicians and also providing critical support for academic medical centers. Using a large-scale, multicenter database, the authors were able to confirm that well-matched cohorts with—and without—resident presence had similar complication profiles. Moreover, even when residents were involved in comparably more complex cases with longer operative times, infection, graft and flap failure, and mortality remained similar. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

An algorithmic approach for selective acellular dermal matrix use in immediate two-stage breast reconstruction: indications and outcomes.

Background: Acellular dermal matrix use has gained widespread acceptance—despite higher material costs—because of its ease of use and potential for enhanced cosmesis. The authors developed a resource-sensitive algorithm for selective acellular dermal matrix use with indications and contraindications based on body mass index, breast size, radiation therapy, flap vascularity, and pectoralis anatomy. Methods: The algorithm incorporates preoperative and intraoperative decision points. Complication rates and aesthetic scores were compared for procedures performed before and after adoption of the algorithm. Multiple logistic regression was used to determine the independent influence of the algorithm on postoperative outcomes. Results: One hundred ninety-three breasts underwent reconstruction before and 179 underwent reconstruction after implementation of the algorithm. Overall complication rates did not differ between the cohorts (22.8 percent versus 20.7 percent; p = 0.138). After adjusting for potential confounders, the algorithm did not significantly affect the incidence of infection, seroma, flap necrosis, explantation, or overall complications (all p > 0.05). Aesthetic scores were not affected (2.75 of 4 versus 3.03 of 4; p = 0.138). Acellular dermal matrix use decreased from 84 percent to 36 percent, resulting in a materials cost savings of

Synergistic interactions with a high intraoperative expander fill volume increase the risk for mastectomy flap necrosis

270,000 over the study period. Conclusions: This algorithm obviated placement of acellular dermal matrix in an estimated 48 percent of immediate tissue-expander reconstructions. Patients treated after adoption of this algorithm experienced similar complication rates and aesthetic outcomes as those who underwent reconstruction before. The authors’ preliminary outcomes demonstrate that evidence-based measures can be taken to selectively use acellular dermal matrix without a concomitant worsening of patient outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

A systematic review of single-stage augmentation-mastopexy.

Purpose Prosthetic-based breast reconstruction is performed with increasing frequency in the United States. Major mastectomy skin flap necrosis is a significant complication with outcomes ranging from poor aesthetic appearance to reconstructive failure. The present study aimed to explore the interactions between intraoperative fill and other risk factors on the incidence of flap necrosis in patients undergoing mastectomy with immediate expander/implant-based reconstruction. Methods A retrospective review of 966 consecutive patients (1,409 breasts) who underwent skin or nipple sparing mastectomy with immediate tissue expander reconstruction at a single institution was conducted. Age, body mass index, hypertension, smoking status, premastectomy and postmastectomy radiation, acellular dermal matrix use, and application of the tumescent mastectomy technique were analyzed as potential predictors of flap necrosis both independently and as synergistic variables with high intraoperative fill. The following three measures of interaction were calculated: relative excess risk due to interaction, attributable proportion of risk due to interaction, and synergy index (SI). Results Intraoperative tissue expander fill volume was high (≥66.7% of the maximum volume) in 40.9% (576 of 1,409 breasts) of cases. The unadjusted flap necrosis rate was greater in the high intraoperative fill cohort than in the low fill cohort (10.4% vs. 7.1%, p=0.027). Multivariate logistic regression did not identify high intraoperative fill volume as an independent risk factor for flap necrosis (odds ratio 1.442, 95% confidence interval 0.973-2.137, p=0.068). However, four risk factors were identified that interacted significantly with intraoperative fill volume, namely tumescence, age, hypertension, and obesity. The SI, or the departure from additive risks, was largest for tumescence (SI, 25.3), followed by hypertension (SI, 2.39), obesity (SI, 2.28), and age older than 50 years (SI, 1.17). Conclusion In the postmastectomy, hypovascular milieu, multiple risk factors decreasing flap perfusion interact with high intraoperative fill volume to cross a threshold and synergistically increase the risk of flap necrosis.

Predictors and causes of unplanned re-operations in outpatient plastic surgery: a multi-institutional analysis of 6749 patients using the 2011 NSQIP database

Background: The safety of single-stage augmentation-mastopexy remains controversial given the dual purpose of increasing breast volume and decreasing the skin envelope. Currently, the literature is relatively sparse and heterogeneous. This systematic review considered complication profiles and pooled summary estimates in an attempt to guide surgical decision-making. Methods: Multiple databases were queried for combined augmentation-mastopexy outcomes. Whenever possible, meta-analysis of complication rates was performed. Results: Twenty-three studies met inclusion criteria. Average follow-up varied from 16 to 173 weeks, with a majority under 1 year. The pooled total complication rate was 13.1 percent (95 percent CI, 6.7 to 21.3 percent). The most common individual complication was recurrent ptosis, with an incidence of 5.2 percent (95 percent CI, 3.1 to 7.8 percent), followed by poor scarring (3.7 percent; 95 percent CI, 1.9 to 6.1 percent). The pooled incidences of capsular contracture and tissue-related asymmetry were 3.0 percent (95 percent CI, 1.4 to 5.0 percent) and 2.9 percent (95 percent CI, 1.2 to 5.4 percent), respectively. Infection, hematoma, and seroma were rare, with pooled incidences of less than 2 percent each. Three published studies reported data on patient satisfaction. The reoperation rate obtained from 13 studies was 10.7 percent (95 percent CI, 6.7 to 15.4 percent). Conclusions: This meta-analysis encompassed 4856 cases of simultaneous augmentation-mastopexy. Study heterogeneity was high because of differences in surgical techniques, outcome definitions, and follow-up durations. This review suggests that with careful patient selection, pooled complication and reoperation rates for single-stage augmentation-mastopexy are acceptably low.

The relationship between preoperative wound classification and postoperative infection: A multi-institutional analysis of 15,289 patients

Abstract Unplanned re-operations carry significant implications for healthcare services, surgical outcomes, and patient safety. However, there has been a paucity of large scale, multi-centre studies that evaluate the predictors and causes of unplanned re-operation in outpatient plastic surgery. This study retrospectively reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) and identified all plastic surgery outpatient cases performed in 2011. Multiple logistic regression analysis was utilised to identify independent risk factors and causes of unplanned reoperations. Of the 6749 outpatient plastic surgery cases identified, there were 125 (1.9%) unplanned re-operations (UR). Regression analysis demonstrated that body mass index (BMI, OR = 1.041, 95% CI = 1.019–1.065), preoperative open wound/wound infection (OR = 3.498, 95% CI = 1.593–7.678), American Society of Anesthesiologists (ASA) class 3 (OR = 2.235, 95% CI = 1.048–4.765), and total work relative value units (RVU, OR = 1.014, 95% CI = 1.005–1.024) were significantly predictive of UR. Additionally, the presence of any complication was significantly associated with UR (OR = 15.065, 95% CI = 5.705–39.781). In an era of outcomes-driven medicine, unplanned re-operation is a critical quality indicator for ambulatory plastic surgery facilities. The identified risk factors will aid in surgical planning and risk adjustment.

Risk factors for complications differ between stages of tissue-expander breast reconstruction

Background Despite advances in surgical techniques, sterile protocols, and perioperative antibiotic regimens, surgical site infections (SSIs) remain a significant problem. We investigated the relationship between wound classification (i.e., clean, clean/contaminated, contaminated, dirty) and SSI rates in plastic surgery. Methods We performed a retrospective review of a multi-institutional, surgical outcomes database for all patients undergoing plastic surgery procedures from 2006-2010. Patient demographics, wound classification, and 30-day outcomes were recorded and analyzed by multivariate logistic regression. Results A total of 15,289 plastic surgery cases were analyzed. The overall SSI rate was 3.00%, with superficial SSIs occurring at comparable rates across wound classes. There were similar rates of deep SSIs in the clean and clean/contaminated groups (0.64%), while rates reached over 2% in contaminated and dirty cases. Organ/space SSIs occurred in less than 1% of each wound classification. Contaminated and dirty cases were at an increased risk for deep SSIs (odds ratios, 2.81 and 2.74, respectively); however, wound classification did not appear to be a significant predictor of superficial or organ/space SSIs. Clean/contaminated, contaminated, and dirty cases were at increased risk for a postoperative complication, and contaminated and dirty cases also had higher odds of reoperation and 30-day mortality. Conclusions Analyzing a multi-center database, we found that wound classification was a significant predictor of overall complications, reoperation, and mortality, but not an adequate predictor of surgical site infections. When comparing infections for a given wound classification, plastic surgery had lower overall rates than the surgical population at large.

Seroma in Prosthetic Breast Reconstruction.

BackgroundTissue-expander (TE) placement followed by implant exchange is currently the most popular method of breast reconstruction. There is a relative paucity of data demonstrating patient factors that predict complications specifically by stage of surgery. The present study attempts to determine what complications are most likely to occur at each stage and how the risk factors for complications vary by stage of reconstruction. MethodsA retrospective chart review was performed on all 1275 patients who had TEs placed by the 2 senior authors between 2004 and 2013. Complication rates were determined at each stage of reconstruction, and these rates were further compared between patients who had pre-stage I radiation, post-stage I radiation, and no radiation exposure. Multivariate logistic regression was used to identify independent predictors of complications at each stage of reconstruction. ResultsA total of 1639 consecutive TEs were placed by the senior authors during the study period. The overall rate for experiencing a complication at any stage of surgery was 17%. Complications occurred at uniformly higher rates during stage I for all complications (92% stage I vs 7% stage II vs 1% stage III, P < 0.001). Predictors of stage I complications included increased body mass index [odds ratio (OR), 1.04; 95% confidence interval (CI), 1.01–1.07], current smoking status (OR, 3.0; 95% CI, 1.7–4.8), and higher intraoperative percent fill (OR, 3.3; 95% CI, 1.7–6.3). Post-stage I radiation was the only independent risk factor for a stage II complication (OR, 4.5; 95% CI, 1.4–15.2). ConclusionsComplications occur at higher rates after stage I than after stage II, and as expected, stage III complications are exceedingly rare. Risk factors for stage I complications are different from risk factors for stage II complications. Body mass index and smoking are associated with complications at stage I, but do not predict complications at stage II surgery. The stratification of risk factors by stage of surgery will help surgeons and patients better manage both risk and expectations.