Use of Banked Fibula for Improved Nasal Reconstruction Following Free Fibula Midface Reconstruction.

OBJECTIVE: Anterior maxillary deficiency caused by trauma or oncologic resection presents a complex reconstructive challenge. The authors present a technique for 2-stage midface reconstruction utilizing a vascularized free fibula flap for maxillary reconstruction, followed by nasal reconstruction at a second stage utilizing a banked fibula graft. METHODS: This case series utilizes a 2-stage technique for midface reconstruction. In the first stage, a fibula-free flap was used to reconstruct the maxilla with the excess banked in the abdomen. In the second stage, this bone graft was used to restore the nasal dorsum. RESULTS: Two patients were included in this series. Patient 1 was a 28-year-old man who presented after a remote gunshot wound to his face, resulting in complete loss of his anterior maxilla and nasal support with midface collapse. Patient 2 was a 65-year-old man who presented with squamous cell carcinoma of the hard palate with extension into the maxilla and nasal septum. In both cases, the flaps healed without complication, providing midface restoration. Placement of the banked fibula graft in a second stage resulted in restoration of dorsal nasal projection. CONCLUSION: The authors describe the use of "spare" fibula parts for nasal reconstruction after loss of the maxilla and cartilaginous septum. The use of the fibula bone as a graft to restore the nasal dorsum in a delayed manner allows for a better assessment of the esthetic needs after the massive swelling from the initial surgery has abated. Further, this approach eliminates the need for a second donor site for nasal reconstruction.

Timeline and Incidence of Postoperative Complications in Prepectoral, Dual-Plane, and Total Submuscular Alloplastic Reconstruction With and Without Biosynthetic Scaffold Usage.

INTRODUCTION: Acellular dermal matrices and synthetic meshes are commonly used to improve inframammary-fold definition, minimize muscle excision, and allow for greater control over the surgical technique in implant-based breast reconstruction. The aims of this study are to compare various combinations of placement planes and biosynthetic scaffolds and to further examine the respective incidences of postoperative complications and the timeline of capsular contracture development. METHODS: A data set consisting of 220 patients (393 samples) who underwent 2-stage reconstruction between 2012 and 2021 was used in the study. χ 2 , Fisher exact test, and 1-way analysis of variance were used to identify significant differences between the 4 subgroups. Cox proportional-hazards model and Kaplan-Meier estimator were used for survival analysis. RESULTS: On univariate logistic regression (odds ratio, 0.21; P = 0.005), survival analysis ( P = 0.0082), and Cox-proportional hazard model (hazard ratio, 1.6; P = 0.01), poly-4-hydroxybutyrate mesh usage was linked to an increased risk of capsular contracture development. Prepectoral placement with no mesh and dual-plane placement with acellular dermal matrix showed similar timelines of capsular contracture development. The lowest incidences of capsular contracture occurred in the prepectoral placement and no mesh (49/161, 30.4%) and total submuscular subgroups (3/14, 21.4%). Infection, necrosis, and revision surgery rates did not differ significantly between the 4 groups. CONCLUSIONS: The use of poly-4-hydroxybutyrate mesh in 2-stage breast reconstruction is correlated with a statistically significant increase in capsular contracture. Prepectoral placement with no biosynthetic scaffold had one of the lowest rates of contracture and may provide the most optimal balance between economic and clinical considerations in implant-based reconstruction.

An Evaluation of Native Breast Dimension and Tissue Expander Inflation Rate on the Risk of Capsular Contracture Development in Postmastectomy Reconstruction.

INTRODUCTION: Capsular contracture is a common complication after 2-stage breast reconstruction. The relationships between native breast size, the rate of tissue expander expansion, and capsule formation have not been elucidated. This study aims to evaluate how these factors contribute to capsular contracture and establish cutoff values for increased risk. METHODS: A data set consisting of 229 patients who underwent 2-stage breast reconstruction between 2012 and 2021 was included in the study. The rate of expansion is estimated as the final expanded volume subtracted by the initial filling volume of the tissue expander over time elapsed. The native breast size was estimated using various preoperative breast measurements and the weight of mastectomy specimen (grams). Further stratified analysis evaluated patients separately based on postoperative radiation status. RESULTS: Greater nipple-inframammary fold distance and faster tissue expander enlargement rate conferred decreased odds of developing capsular contracture ( P < 0.05). On stratified analysis, faster tissue expansion rate was not significant in the nonradiated cohort but remained a significant negative predictor in the radiation group (odds ratio, 0.996; P < 0.05). Cut-point analysis showed an expansion rate of <240 mL/mo and a nipple-inframammary fold value of <10.5 cm as conferring a greater risk of capsular contracture. CONCLUSION: Smaller inframammary fold distance may be associated with a higher risk of capsular contracture. Slower expansion rates correlate with increased odds of contracture in patients undergoing adjuvant radiation. Breast geometry should be considered when risk stratifying various reconstruction approaches (implant vs autologous). In addition, longer delays between implant exchange and initial tissue expansion should be avoided if clinically feasible.

Postoperative Tachycardia in Deep Inferior Epigastric Perforator Flap Breast Reconstruction: Is It a Reason to Worry?

BACKGROUND: Many patients who undergo free flap breast reconstruction develop postoperative hemodynamic changes, most noticeably, tachycardia. As there is currently no consensus on whether this tachycardia leads to clinically significant morbidity, it can trigger physician alarm and lead to extensive work-up. In this study, we aim to evaluate the predictors, evaluation, and outcomes associated with postoperative tachycardia in deep inferior epigastric perforator (DIEP) flap patients. METHODS: A retrospective review of DIEP flap patients between 2011 and 2020 was performed. Variables examined included demographics, preoperative laboratories and heart rate (HR), and intraoperative factors. Work-up of postoperative tachycardia and adverse postoperative events was noted. Tachycardia was defined as persistent HR of 100 beats/min or more for at least 12 consecutive hours following surgery. Tachycardic patients were compared with non-tachycardic patients using regression analysis. RESULTS: In total, 249 patients (439 flaps) were included in this study. Sixty-one patients (24.9%) developed tachycardia postoperatively. Regression analysis revealed that preoperative HR (p = 0.002) and flap weight (p = 0.037) predicted the development of tachycardia. While tachycardic patients were significantly more likely to undergo additional imaging and specialty consultations (p <0.05), they were not at higher risk for most postoperative complications, with the exception of delayed abdominal donor-site healing. CONCLUSION: A significant number of DIEP flap patients can be expected to develop persistent tachycardia postoperatively. Isolated tachycardia should be considered a relatively benign finding that does not warrant extensive work-up or prolonged inpatient monitoring. Having the ability to predict tachycardia using preoperative HR and flap weight arms plastic surgeons with the confidence to limit costly work-up.

Pediatric Pain and Pain Management After Ambulatory Plastic Surgery: Trends in the Age of Opioid Awareness.

BACKGROUND: Overprescribing by physicians has been shown to be a major contributor to the opioid epidemic. Although pediatric ambulatory plastic surgery patients are commonly prescribed opioids for postoperative pain control, there is a lack of evidence for their necessity. This study aimed to investigate the role of prescribed narcotics in the ambulatory pediatric plastic surgery setting. METHODS: All assenting patients/guardians, ages 0 to 17 years, who underwent an ambulatory plastic surgery procedure by 1 attending surgeon from March 2018 to March 2019, were asked to participate in the study. A questionnaire was distributed at the first postoperative visit to interrogate postoperative pain, management, and narcotic use. RESULTS: A total of 95 patients/guardians completed the questionnaire. Seventy-eight percent (74) of patients picked up the narcotic medication, with 33% (31) taking at least 1 dose of narcotics, and only 9% (9) taking 4 or more doses. Patients overall found no difference in efficacy of the narcotics versus nonprescription analgesics (3.93/5 and 4.31/5, P = 0.11). Age was a significant predictor, with older patients requiring more narcotics (odds ratio, 1.12; 95% confidence interval, 1.02-1.24; P = 0.019). The type of surgery a patient underwent was not a significant predictor of the amount of narcotic used. Few patients knew how to properly dispose of the excess narcotics, with almost 50% still having it stored in their homes. CONCLUSIONS: This study demonstrates that the majority of pediatric ambulatory plastic surgery patients do not require narcotic pain medications and experience adequate pain relief with over-the-counter analgesics. Importantly, education on proper disposal of narcotic medications may be a simple, yet effective target to decrease opioid availability for abuse.

Prolonged Venous Thromboembolism Prophylaxis May Not Be Necessary for DIEP Flap Breast Reconstruction: A Tertiary Center's 10-Year Experience.

BACKGROUND: Based on the 2005 Caprini Risk Assessment Model for venous thromboembolism, the American Society of Plastic Surgeons prevention guidelines would result in prolonged chemoprophylaxis (1 week or more) for the majority of patients undergoing deep inferior epigastric perforator flap breast reconstruction. We aim to assess the necessity of prolonged prophylaxis by describing our institutional experience in thromboembolism prevention and evaluating the incidence of symptomatic VTE in our patient cohort. METHODS: Women who underwent DIEP flap reconstruction from August 2011 to March 2020 at a tertiary care center were included. Charts were retrospectively reviewed for patient characteristics, VTE prophylaxis regimens, and development of deep vein thrombosis and pulmonary embolism within 60 days of surgery. Caprini scores were calculated for all patients. RESULTS: Out of the 249 patients included in the study, 245 patients received chemoprophylaxis only during hospitalization, while four patients additionally received anticoagulant for at least 2 weeks after discharge for prophylactic or therapeutic indications. The cohort's average Caprini score was 6.0, with 72.7% of scores between 3 and 6 and 26.5% at 7 or higher. One patient (0.4%), who scored a 7 and received prophylaxis only while hospitalized, developed deep vein thrombosis. There were no cases of pulmonary embolism. There was no significant difference in VTE rate between patients who received chemoprophylaxis consistent with ASPS guidelines and those who did not (p = 1.000). CONCLUSION: Despite our limited chemoprophylaxis use in DIEP flap patients, our VTE incidence is low. This current work suggests that the blanket application of prolonged prophylaxis is not warranted, and it further serves as impetus to re-evaluate the 2005 Caprini RAM in this patient population.

Poly-4-hydroxybutyrate (Phasix™) mesh onlay in complex abdominal wall repair.

BACKGROUND: Poly-4-hydroxybutyric acid (P4HB, Phasix™) is a biosynthetic polymer that degrades by hydrolysis that can be woven into a mesh for use in soft tissue reinforcement. Herein, we describe our initial experience performing complex abdominal wall repair (CAWR) utilizing component separation and P4HB mesh as onlay reinforcement. METHODS: All patients undergoing CAWR between June 2014 and May 2017 were followed prospectively for postoperative outcomes. Only those patients who underwent components separation with primary repair of the fascial edges followed by onlay of P4HB mesh were included in this study. RESULTS: 105 patients (52 male, 53 female; mean age 59.2 years, range 22-84) met inclusion criteria. Mean BMI was 29.1 (range 16-48); 52% patients had prior attempted hernia repair, most with multiple medical comorbidities (71% of patients with ASA 3 or greater). 30% of cases were not clean at the time of repair (CDC class 2 or greater). Median follow-up was 36 months (range 9-63). Eighteen patients (17%) developed a hernia recurrence ranging from 2 to 36 months postoperatively. Five (5%) patients developed a localized superficial infection treated with antibiotics, three (2.8%) required re-operation for non-healing wounds, and six (6%) patients developed seroma. CONCLUSIONS: These data demonstrate a relatively low rate of hernia recurrence, seroma, and other common complications of CAWR in a highly morbid patient population. Importantly, the rate of mesh infection was low and no patients required complete mesh removal, even when placed into a contaminated or infected surgical field.

Is It Worth the Risk? Contralateral Prophylactic Mastectomy With Immediate Bilateral Breast Reconstruction.

BACKGROUND: An increasing number of women are choosing to undergo contralateral prophylactic mastectomy with immediate bilateral breast reconstruction. Operating on the contralateral noncancer side is not without its own set of risks. We sought to compare complication rates between the cancerous and contralateral prophylactic breasts. METHODS: A retrospective review was conducted of all patients undergoing immediate postmastectomy bilateral breast reconstruction for unilateral breast cancer between January 2008 and January 2019 at a single institution. Data were collected on patient demographics, cancer and adjuvant/neoadjuvant treatments, tumor, reconstruction, hospital stay, and complications. Complications were compared between the cancerous and the noncancerous breasts. RESULTS: One hundred sixty patients met the inclusion criteria of this study. Of these 160 patients, 33 (20.6%) had complications (major and minor) only to the cancerous breast, 7 (4.4%) had complications only to the noncancerous breast, and 7 (4.4%) had bilateral complications. Most patients underwent tissue expander/implant reconstruction (93.8%) with the rest (6.2%) undergoing abdominally based flap or latissimus dorsi flap reconstruction. Patients with complications were more likely to have hypertension, diabetes, exposure to radiation, and neoadjuvant chemotherapy. Complications included wound dehiscence, hematoma, cellulitis, seroma, capsular contracture, infected implant, and skin necrosis. Overall, there were significantly more complications to the cancerous breasts than the noncancerous breasts (P < 0.001). In addition, although exposure to radiation to the affected side significantly increased the likelihood of complications to that side (P < 0.0001), patients who were not exposed to any radiation were also more likely to have complications to the cancer side than to the noncancer side (P = 0.00065). However, after controlling for the effects of radiation, there was no significant difference in complications between the cancer side and the prophylactic side when stratifying by specific complications. CONCLUSIONS: Although contralateral prophylactic mastectomy with immediate bilateral reconstruction is not without added risk when compared with a unilateral procedure, this study shows that the incidence of complications to the noncancerous breast is less than that to the cancerous breast. This information can be used to help counsel patients with unilateral breast cancer on their treatment options and associated risks.

Poly-4-Hydroxybutyric Acid Mesh Compares Favorably With Acellular Dermal Matrix in Tissue Expander-Based Breast Reconstruction.

BACKGROUND: Acellular dermal matrix (ADM) is commonly used during immediate expander-based breast reconstruction, with potential advantages of greater intraoperative expansion, decreased time to complete expansion, and decreased rates of capsular contracture. However, ADM is associated with increased infection rate, seroma, and subsequent reconstructive failure. Poly-4-hydroxybutyric acid (P4HB) mesh is a large pore, biosynthetic scaffold shown to fully resorb and incorporate host tissues within 18 months. We sought to compare outcomes between the use of P4HB and ADM in immediate retropectoral expander-based reconstruction. METHODS: One hundred ninety-two consecutive cases (107 patients) of breast reconstruction using ADM were compared with a subsequent cohort of 112 cases (62 patients) using P4HB mesh. In all patients, reconstruction was performed immediately after mastectomy by a single surgeon, and outcomes were compared between groups. RESULTS: Baseline characteristics were similar between the P4HB and ADM groups. Overall infection rates were lower, but not significantly with P4HB (11% vs 17%, P = 0.18). Time to drain removal was significantly lower with P4HB (15 vs 18 days, P = 0.008), although there was no difference in rates of seroma (0.9% vs 3%, P = 0.43). Similar numbers of patients underwent external beam radiation (22% vs 24%) and received chemotherapy in each group (48% vs 45%). By univariate analysis, all odds ratios were decreased with use of P4HB, including risk of major complications (0.55), seroma (0.17), infection (0.59), need for reoperation (0.78), and skin necrosis (0.77). CONCLUSIONS: Initial findings suggest P4HB mesh to be a safe alternative to ADM in expander-based breast reconstruction, with trends toward decreased rates of infection, seroma, and need for device removal using P4HB mesh. Although our results are limited to a small series of initial patients, P4HB mesh may be a promising novel technique to decrease complications inherent to use of ADM at a reduced material cost.

Reconstruction of Full Thickness Scalp Defects in Extremely Elderly Patients Using Dermal Regeneration Templates.

The reconstruction of full thickness scalp defects following oncologic resection poses a unique challenge that is further magnified in "extremely elderly" patients, defined as those in at least their ninth decade of life, who are often unsuitable candidates for complex reconstruction. A "simpler" option is two-stage reconstruction: placement of Integra dermal regenerative template (Integra Life Science, Plainsboro, NJ) followed by a split thickness skin graft (STSG). This case series illustrates the success of this technique in the extremely elderly. A retrospective analysis of patients > 80 years at the time of surgery who underwent full thickness scalp reconstruction following tumor extirpation in a two-stage approach under the care of single surgeon from January 2010 to June 2019 was conducted. Variables reviewed were medical history, surgical treatment response, time to split thickness skin graft, follow up, and success of wound coverage. Fourteen patients, with a mean age of 87 years (range: 80 to 101, median: 87), met inclusion criteria. Split thickness skin grafts were placed after an average of 18 days. Twelve patients had successful two-stage reconstruction with 100% take. One patient developed a hematoma under a portion of the template that neither required reoperation nor delayed split thickness skin graft placement. A second suffered from insufficient vascularization of the template with delay to split thickness skin graft and incomplete wound closure. This two-stage approach is a successful primary reconstructive option for definitive management of full thickness scalp defects following oncologic resection in extremely elderly patients.

Tissue Engineering Auricular Cartilage Using Late Passage Human Auricular Chondrocytes.

PURPOSE: The significant shortcomings associated with current autologous reconstructive options for auricular deformities have inspired great interest in a tissue engineering solution. A major obstacle in the engineering of human auricular cartilage is the availability of sufficient autologous human chondrocytes. A clinically obtainable amount of auricular cartilage tissue (ie, 1 g) only yields approximately 10 million cells, where 25 times this amount is needed for the fabrication of a full-scale pediatric ear. It is thought that repeated passaging of chondrocytes leads to dedifferentiation and loss of the chondrogenic potential. However, little to no data exist regarding the ideal number of times that human auricular chondrocytes (HAuCs) can be passaged in a manner that maximizes the cellular expansion while minimizing dedifferentiation. METHODS: Human auricular chondrocytes were isolated from discarded otoplasty specimens. The HAuCs were then expanded, and cells from passages 3, 4, and 5 were encapsulated into discs 8 mm in diameter made from type I collagen hydrogels with a cell density of 25 million cells/mL. The constructs were implanted subcutaneously in the dorsa of nude mice and harvested after 1 and 3 months for analysis. RESULTS: Constructs containing passages 3, 4, and 5 chondrocytes all maintained their original cylindrical geometry. After 3 months in vivo, the diameters of the P3, P4, and P5 discs were 69 ± 9%, 67 ± 10%, and 73 ± 15% of their initial diameter, respectively. Regardless of the passage number, all constructs developed a glossy white cartilaginous appearance, similar to native auricular cartilage. Histologic analysis demonstrated development of an organized perichondrium composed of collagen, a rich proteoglycan matrix, cellular lacunae, and a dense elastin fibrin network by Safranin-O and Verhoeff stain. Biochemical analysis confirmed similar amounts of proteoglycan and hydroxyproline content in late passage constructs when compared with native auricular cartilage. CONCLUSIONS: These data indicate that late passage HAuCs (up to passage 5) form elastic cartilage that is histologically, biochemically, and biomechanically similar to native human elastic cartilage and have the potential to be used for auricular cartilage engineering.

In Search of a Murine Model of Radiation-Induced Periprosthetic Capsular Fibrosis.

INTRODUCTION: Capsular contracture after breast reconstruction is a morbid complication, occurring in 30.0% to 47.5% of patients undergoing postoperative radiotherapy. Although it is well known that radiation increases rate of capsular contracture, there are few well-established animal models that faithfully replicate standard-of-care clinical practice, that is, prosthesis placement at the time of mastectomy followed by delayed radiotherapy. To better recapitulate current clinical practice, we developed a murine model in which the implant sites were irradiated 10 days postoperatively, rather than at time of surgery. METHODS: Hemispherical implants were created from polydimethylsiloxane and implanted bilaterally in the subcutaneous dorsa of 20 C57Bl/6 mice. Mice were randomized to 5 treatment groups, differing in irradiation dose: 0 to 40 Gy. Ten days postoperatively, irradiation was performed using 250-kVp x-rays (XRAD225Cx, Precision X-ray, North Branford, Conn). In 1 mouse per group, dosimeters were placed subcutaneously to measure the delivered absorbed dose. Thirty-one days postoperatively, the mice were sacrificed and examined grossly, and periprosthetic tissues were removed for histologic analysis of periprosthetic capsule thickness and cellular deposition. RESULTS: Total radiation dose was calculated by the treatment planning software and confirmed by the in vivo dosimeters. Physical examination of the irradiated region demonstrated evidence of local radiation delivery, including circular patterns of hair blanching and thinning directly over the implants. Furthermore, histologic analysis of the irradiated epidermis demonstrated dose-dependent radiation changes including keratin whorls and patches of uneven epidermal thickness. There was no statistically significant difference in capsule thickness among the groups. Mice in the 30 and 40 Gy groups endured complications including shortness of breath, coagulopathy, and death, signs of systemic radiation poisoning. CONCLUSIONS: There was no evidence of increased periprosthetic capsule thickness with localized irradiation, irrespective of dose up to 20 Gy. These results differ from those previously published, which demonstrated increased capsule thickness with 10 Gy irradiation. Given the evidence of local radiation delivery, we believe that the lack of increase in capsule thickness observed in our experiment is a real phenomenon and demonstrate the difficulty in creating an easily reproducible rodent model that mimics the effects of postmastectomy implant-based reconstruction and irradiation.

Current status of cost utility analyses in total joint arthroplasty: a systematic review.

BACKGROUND: Total joint arthroplasty (TJA), although considered to be highly beneficial, is associated with substantial costs to the US healthcare system. Cost utility analysis has become an increasingly important means to objectively evaluate the value of a healthcare intervention from the perspective of both extending the quantity and improving the quality of life. Relatively little is known about the overall cost utility analysis evidence base in TJA. QUESTIONS/PURPOSES: The goals of this review were to (1) determine the cost utility of TJA interventions; (2) critically assess the quality of published US-based cost utility analyses using the Quality of Health Economic Studies instrument; and (3) determine what characteristics were common among studies receiving a high quality score. METHODS: A systematic review of the literature using the MEDLINE database was performed to compile findings and critically appraise US-based cost utility analysis studies for total hip and knee arthroplasty. Based on review of 676 identified articles, 23 studies were included. We used the Quality of Health Economic Studies instrument to assess study quality and one-sided Fisher's exact tests were applied to analyze the predictors of high-quality cost utility analysis. RESULTS: Very few studies compare the cost utility of TJA versus nonoperative intervention; however, the available evidence suggests that TJA can be cost-saving and is highly cost-effective compared with conservative management of end-stage arthritis. The majority of identified studies are focused on the cost utility of new implant technologies or comparisons among surgical alternatives. These studies suggest that the upfront costs associated with new technologies are cost-effective when there is a major reduction in a future cost. The quality of identified studies is quite high (Quality of Health Economic Studies Instrument score: mean 86.5; range, 63-100). National funding source (p = 0.095) and lifetime horizon for analysis (p = 0.07) correlate with high-quality evidence but do not reach significance. CONCLUSIONS: Over the past 15 years, there has been a major increase in the volume of cost utility analyses published in total hip and knee arthroplasty. The quality of cost utility analyses published during that period is good. As increasing attention is paid to value in US health care, more attention should be paid to understanding the cost utility of TJA compared with nonoperative treatment modalities. Future studies may also look to incorporate patient willingness to pay.

An Antifibrotic Breast Implant Surface Coating Significantly Reduces Periprosthetic Capsule Formation.

BACKGROUND: The body responds to prosthetic materials with an inflammatory foreign body response and deposition of a fibrous capsule, which may be deleterious to the function of the device and cause significant discomfort for the patient. Capsular contracture (CC) is the most common complication of aesthetic and reconstructive breast surgery. The source of significant patient morbidity, it can result in pain, suboptimal aesthetic outcomes, implant failure, and increased costs. The underlying mechanism remains unknown. Treatment is limited to reoperation and capsule excision, but recurrence rates remain high. In this study, the authors altered the surface chemistry of silicone implants with a proprietary anti-inflammatory coating to reduce capsule formation. METHODS: Silicone implants were coated with Met-Z2-Y12, a biocompatible, anti-inflammatory surface modification. Uncoated and Met-Z2-Y12-coated implants were implanted in C57BL/6 mice. After 21, 90, or 180 days, periprosthetic tissue was removed for histologic analysis. RESULTS: The authors compared mean capsule thickness at three time points. At 21, 90, and 180 days, there was a statistically significant reduction in capsule thickness of Met-Z2-Y12-coated implants compared with uncoated implants ( P < 0.05). CONCLUSIONS: Coating the surface of silicone implants with Met-Z2-Y12 significantly reduced acute and chronic capsule formation in a mouse model for implant-based breast augmentation and reconstruction. As capsule formation obligatorily precedes CC, these results suggest contracture itself may be significantly attenuated. Furthermore, as periprosthetic capsule formation is a complication without anatomical boundaries, this chemistry may have additional applications beyond breast implants, to a myriad of other implantable medical devices. CLINICAL RELEVANCE STATEMENT: Coating of the silicone implant surface with Met-Z2-Y12 alters the periprosthetic capsule architecture and significantly reduces capsule thickness for at least 6 months postoperatively in a murine model. This is a promising step forward in the development of a therapy to prevent capsular contracture.

Machine-Learning Prediction of Capsular Contraction after Two-Stage Breast Reconstruction.

Background: Two-stage breast reconstruction is a common technique used to restore preoperative appearance in patients undergoing mastectomy. However, capsular contracture may develop and lead to implant failure and significant morbidity. The objective of this study is to build a machine-learning model that can determine the risk of developing contracture formation after two-stage breast reconstruction. Methods: A total of 209 women (406 samples) were included in the study cohort. Patient characteristics that were readily accessible at the preoperative visit and details pertaining to the surgical approach were used as input data for the machine-learning model. Supervised learning models were assessed using 5-fold cross validation. A neural network model is also evaluated using a 0.8/0.1/0.1 train/validate/test split. Results: Among the subjects, 144 (35.47%) developed capsular contracture. Older age, smaller nipple-inframammary fold distance, retropectoral implant placement, synthetic mesh usage, and postoperative radiation increased the odds of capsular contracture (p < 0.05). The neural network achieved the best performance metrics among the models tested, with a test accuracy of 0.82 and area under receiver operative curve of 0.79. Conclusion: To our knowledge, this is the first study that uses a neural network to predict the development of capsular contraction after two-stage implant-based reconstruction. At the preoperative visit, surgeons may counsel high-risk patients on the potential need for further revisions or guide them toward autologous reconstruction.

Nipple Engineering: Maintaining Nipple Geometry with Externally Scaffolded Processed Autologous Costal Cartilage.

INTRODUCTION: Nipple reconstruction is the essential last step of breast reconstruction after total mastectomy, resulting in improved general and aesthetic satisfaction. However, most techniques are limited by secondary scar contracture and loss of neo-nipple projection leading to patient dissatisfaction. Approximately, 16,000 patients undergo autologous flap breast reconstruction annually, during which the excised costal cartilage (CC) is discarded. We propose utilizing processed CC placed within biocompatible 3D-printed external scaffolds to generate tissue cylinders that mimic the shape, size and biomechanical properties of native human nipple tissue while mitigating contracture and projection loss. METHODS: External scaffolds were designed and then 3D-printed using polylactic acid (PLA). Patient-derived CC was processed by mincing or zesting, then packed into the scaffolds, implanted into nude rats and explanted after 3 months for volumetric, histologic and biomechanical analyses. Similar analyses were performed on native human nipple tissue and unprocessed CC. RESULTS: After 3 months in vivo, gross analysis demonstrated significantly greater preservation of contour, projection and volume of the scaffolded nipples. Mechanical analysis demonstrated that processing of the cartilage resulted in implant equilibrium modulus values closer to that of the human nipple. Histologic analysis showed the presence of healthy and viable cartilage after 3 months in vivo, invested with fibrovascular tissue. CONCLUSIONS: Autologous CC can be processed intraoperatively and placed within biocompatible external scaffolds to mimic the shape and biomechanical properties of the native human nipple. This allows for custom design and fabrication of individualized engineered autologous implants tailored to patient desire, without the loss of projection seen with traditional approaches.

Three-Dimensional-Printed External Scaffolds Mitigate Loss of Volume and Topography in Engineered Elastic Cartilage Constructs.

OBJECTIVE: A major obstacle in the clinical translation of engineered auricular scaffolds is the significant contraction and loss of topography that occur during maturation of the soft collagen-chondrocyte matrix into elastic cartilage. We hypothesized that 3-dimensional-printed, biocompatible scaffolds would "protect" maturing hydrogel constructs from contraction and loss of topography. DESIGN: External disc-shaped and "ridged" scaffolds were designed and 3D-printed using polylactic acid (PLA). Acellular type I collagen constructs were cultured in vitro for up to 3 months. Collagen constructs seeded with bovine auricular chondrocytes (BAuCs) were prepared in 3 groups and implanted subcutaneously in vivo for 3 months: preformed discs with ("Scaffolded/S") or without ("Naked/N") an external scaffold and discs that were formed within an external scaffold via injection molding ("Injection Molded/SInj"). RESULTS: The presence of an external scaffold or use of injection molding methodology did not affect the acellular construct volume or base area loss. In vivo, the presence of an external scaffold significantly improved preservation of volume and base area at 3 months compared to the naked group (P < 0.05). Construct contraction was mitigated even further in the injection molded group, and topography of the ridged constructs was maintained with greater fidelity (P < 0.05). Histology verified the development of mature auricular cartilage in the constructs within external scaffolds after 3 months. CONCLUSION: Custom-designed, 3D-printed, biocompatible external scaffolds significantly mitigate BAuC-seeded construct contraction and maintain complex topography. Further refinement and scaling of this approach in conjunction with construct fabrication utilizing injection molding may aid in the development of full-scale auricular scaffolds.

Muscle Flap Closure following Complex Spine Surgery: A Decade of Experience.

BACKGROUND: Advances in surgical technology and adjuvant therapies along with an aging and increasingly morbid U.S. population have led to an increase in complex spine surgery. With this increase comes an elevated risk of complications, including those related to the surgical wound, with some studies demonstrating wound complication incidences approaching 45 percent. The authors hypothesize that immediate muscle flap closure improves outcomes in high-risk patients. METHODS: Three hundred one consecutive index cases of spinal wound closure using local muscle flaps performed by the senior author at a single institution between 2006 and 2018 were reviewed. The primary outcome was major wound complication (reoperation and/or readmission because of surgical-site infection, late infection, dehiscence, seroma, or hematoma). Logistic regression analysis was performed to identify predictors of this endpoint. RESULTS: Major wound complications occurred in 6.6 percent of patients (reoperation, 3.6 percent; readmission, 3.0 percent), with a 6.0 percent infection rate and five cases requiring instrumentation removal because of infection. Risk factors identified included radiotherapy (OR, 5.9; p = 0.004), age 65 years or older (OR, 2.8; p = 0.046), and prior spine surgery (OR, 4.3; p = 0.027). The incidence of major wound complication increased dramatically with each additional risk factor. Mean drain dwell duration was 21.1 ± 10.0 days and not associated with major wound complications, including infection (OR, 1.04; p = 0.112). CONCLUSIONS: Immediate local muscle flap closure following complex spine surgery on high-risk patients is associated with an acceptable rate of wound complications and, as these data demonstrate, is safe and effective. Consideration should be given to immediate muscle flap closure in appropriately selected patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Tissue engineering the human auricle by auricular chondrocyte-mesenchymal stem cell co-implantation.

Children suffering from microtia have few options for auricular reconstruction. Tissue engineering approaches attempt to replicate the complex anatomy and structure of the ear with autologous cartilage but have been limited by access to clinically accessible cell sources. Here we present a full-scale, patient-based human ear generated by implantation of human auricular chondrocytes and human mesenchymal stem cells in a 1:1 ratio. Additional disc construct surrogates were generated with 1:0, 1:1, and 0:1 combinations of auricular chondrocytes and mesenchymal stem cells. After 3 months in vivo, monocellular auricular chondrocyte discs and 1:1 disc and ear constructs displayed bundled collagen fibers in a perichondrial layer, rich proteoglycan deposition, and elastin fiber network formation similar to native human auricular cartilage, with the protein composition and mechanical stiffness of native tissue. Full ear constructs with a 1:1 cell combination maintained gross ear structure and developed a cartilaginous appearance following implantation. These studies demonstrate the successful engineering of a patient-specific human auricle using exclusively human cell sources without extensive in vitro tissue culture prior to implantation, a critical step towards the clinical application of tissue engineering for auricular reconstruction.

Local muscle flaps minimize post-operative wound morbidity in patients with neoplastic disease of the spine.

OBJECTIVES: Patients with neoplastic disease involving the spine either from primary or metastatic disease present a unique challenge given these patients' frequent poor nutritional status at the time of surgery, the delivery of early post-operative chemotherapy or radiation, and placement of large amounts of hardware and avascular bone graft into a wound bed that is atrophic, previously operated or irradiated. As a result, wound morbidity has traditionally been high in this cohort of patients. Herein we review the outcomes of patients at our institution who underwent local muscle flap closure following spinal tumor extirpation. PATIENTS AND METHODS: Between 2007 and 2017, 55 patients with oncologic disease of the spine underwent 60 spine surgeries and concomitant muscle flap reconstruction. Charts were retrospectively reviewed for diagnosis and indications for surgery, as well as risk factors for poor wound healing including diabetes, steroid use, body mass index (BMI), history of pre-operative chemo and or radiation therapy, preoperative albumin and hemoglobin levels. Outcomes were postoperative wound related complications including surgical site infection, wound dehiscence and/or need for reoperation. RESULTS: 60 reconstructions were included in 55 patients. Median follow up was 253 days. Paraspinous muscle flaps were used in all cases. There were 2 major complications (3.3%) related to wound infections which required reoperation and 10 minor wound complications (16.7%), of which 9 were subcutaneous seromas aspirated in the office, that did not require return to the operating room. Median postoperative stay in the hospital was 10 days. Closed suction drains placed at the end of the reconstruction were removed at a median of 17.5 days. Regression analysis found patient BMI to be a significant risk predictor for wound related post-operative complications. CONCLUSIONS: Post-operative wound specific complications that required return to the operating room were uncommon despite the high-risk profile of this subset of patients. These data indicate that muscle flap closure should be routinely practiced in this high-risk cohort of patients.