Fat Grafts Show Higher Hypoxia, Angiogenesis, Adipocyte Proliferation, and Macrophage Infiltration than Flaps in a Pilot Mouse Study.

BACKGROUND: Over 137,000 breast reconstructions are performed annually by American Society of Plastic Surgeons (ASPS) members. Vascularized flaps and avascular lipofilling each account for over 33,000 autologous reconstructions. Although clinical and experimental observations suggest biologic differences with diverging effects on locoregional tumor control, comparative animal models are lacking. The authors standardized existing techniques in immunocompetent mice, laying the foundation for in vivo models of autologous breast reconstruction combinable with orthotopic tumor implantations. METHODS: Twenty-five groin flaps and 39 fat grafts were transferred in female BALB/c-mice. Adipocytes were tracked via Hoechst-Calcein-DiI staining ( n = 2 per group), and postoperative volume retentions were compared via magnetic resonance imaging ( n = 3 per group) on days 1, 11, 21, and 31. Proliferation indices, microvessel densities, tissue hypoxia, and macrophage infiltrates were compared via Ki67, CD31, pimonidazole, and hematoxylin-eosin staining on days 5, 10, 15, 20, and 30 ( n = 4 per group). RESULTS: Viable adipocytes were present in both groups. Graft volumes plateaued at 42.7 ± 1.2% versus 81.8 ± 4.0% of flaps ( P < 0.001). Initially, grafts contained more hypoxic cells (day 5: 15.192 ± 1.249 versus 1.157 ± 192; P < 0.001), followed by higher proliferation (day 15: 25.2 ± 1.0% versus 0.0 ± 0.0%; P < 0.001), higher microvessel numbers (day 30: 307.0 ± 13.2 versus 178.0 ± 10.6; P < 0.001), and more pronounced macrophage infiltrates (graded 3 versus 2; P < 0.01). CONCLUSION: This comparative murine pilot study of vascularized flaps versus avascular lipofilling suggests differences in volume retention, proliferation, angiogenesis, hypoxia, and inflammation. CLINICAL RELEVANCE STATEMENT: The biological differences of fat grafting versus flap transfer are not fully understood because no single comparative experimental model has been established to date. The authors present the first comparative small animal model of both techniques, which will allow the gaining of deeper insights into their biological effects.

A Retrospective Comparative Functional and Aesthetic Outcome Study of Muscle versus Cutaneous Free Flaps for Distal Upper Extremity Reconstruction.

BACKGROUND: Function and cosmesis are crucial in upper extremity reconstruction. Yet, there persists a lack of outcome evaluations, particularly regarding differences between free flap types. METHODS: In a single-center retrospective analysis, outcomes were compared between patients with cutaneous or muscle free flaps for distal upper extremity reconstruction between 2008 and 2018. The Disabilities of Arm, Shoulder and Hand -Score, Michigan-Hand (MHQ), and Short Form 36 Health Survey (SF-36) Questionnaires were assessed, motor function was quantified, and self-reported measures of cosmesis were compared, including the Vancouver Scar-Scale (VSS), MHQ aesthetics-subscale (MAS), and Moscona's cosmetic validation-score (CVS). RESULTS: One-hundred forty-one cases were identified, with a shift toward cutaneous flaps over the study period. Muscle flaps were used for larger defects (251 vs. 142 cm2, p = 0.008). Losses, thromboses, and donor-site complications were equally distributed. Partial necroses were more frequent in muscle flaps (11 vs. 1%, p = 0.015). Seventy patients with 53 cutaneous versus 17 muscle flaps were reexamined. There was no difference in the timing of flap coverage (after 16 vs. 15 days, p = 0.79), number of preceding (2 vs. 1.7, p = 0.95), or subsequent operations (19/53 vs. 5/17, p = 0.77). Patients with cutaneous flaps showed higher grip strength (25 vs. 17 kg, p = 0.046) and reported better hand function (MHQ: 58 vs. 47, p = 0.044) and general health (SF-36: 70 vs. 61, p = 0.040), as well as more favorable appearance (MAS: 71 vs. 57, p = 0.044, CVS: 77 vs. 72, p = 0.048), and scar burden (VSS: 0 vs. 3, p < 0.001). CONCLUSION: Cutaneous flaps yielded better motor function, self-perceived cosmesis, patient satisfaction, and quality of life in our cohort of distal upper extremity reconstructions.

Implementation and Validation of Free Flaps in Acute and Reconstructive Burn Care.

Microsurgical free flap reconstruction in acute burn care offers the option of reconstructing even challenging defects in a single stage procedure. Due to altered rheological and hemodynamic conditions in severely burned patients, it bears the risk of a higher complication rate compared to microsurgical reconstruction in other patients. To avoid failure, appropriate indications for free flap reconstruction should be reviewed thoroughly. Several aspects concerning timing of the procedure, individual flap choice, selection and preparation of the recipient vessels, and perioperative measures must be considered. Respecting these specific conditions, a low complication rate, comparable to those seen in microsurgical reconstruction of other traumatic limb defects, can be observed. Hence, the free flap procedure in acute burn care is a relatively safe and reliable tool in the armamentarium of acute burn surgery. In reconstructive burn care, microsurgical tissue transfer is routinely used to treat scar contractures. Due to the more robust perioperative condition of patients, even lower rates of complication are seen in microsurgical reconstruction.

Multidisciplinary team meetings for patients with complex extremity defects: a retrospective analysis of treatment recommendations and prognostic factors for non-implementation.

BACKGROUND: This study aimed to assess a multidisciplinary team (MDT) meeting approach for the management of patients with complex extremity defects, analyze treatment recommendations, and evaluate factors influencing non-implementation. METHODS: All patients introduced to an MDT meeting for complex extremity defects from 2015 to 2017 were included in a retrospective cohort study. Patients' characteristics and defect causes were evaluated. Treatment recommendations (TR) of MDT meetings and subsequent implementation were reviewed (cohort with implementation of TR versus cohort with non-implementation of TR), and factors associated with non-adherence to recommendations were statistically analyzed using logistic regression. RESULTS: Fifty-one patients (41 male) with a mean age of 54 years were presented in 27 MDT meetings. Most of the patients (70%) suffered from reconstructive challenging or combined bone- and soft tissue defects, primarily located at the lower extremity (88%). Large skeletal defects, chronic osteomyelitis, and multi-fragmented fractures were present in 65% of cases. Forty-five percent of the patients suffered from peripheral vascular disease, necessitating surgical optimization. Of the 51 MDT decisions, 40 were implemented (78%; (32/40) limb salvage versus 22%; (8/40) limb amputation). Limb salvage was successfully achieved in 91% (29/32) of the cases. Failed limb salvages were due to flap failure (33%; 1/3), recurring periprosthetic joint infections (66%; 2/3) and concomitant reconstructive failure. Patients who underwent limb amputation, as recommended, showed proper stump healing and regained mobility with a prosthesis. Overall the MDT treatment plan was effective in 92.5% (37/40) of the patients, who adhered to the MDT treatment recommendation. In eleven patients (22%; 11/51), the MDT treatment was not implemented. MDT decisions were less likely to be implemented, if amputation was recommended (p = 0.029). CONCLUSIONS: MDT meetings represent a valid tool to formulate individualized treatment plans, avoiding limb amputation in most patients with severe extremity defects. Recommendation for limb amputation is less likely to be implemented than plans for limb salvage. TRIAL REGISTRATION: Retrospectively registered.

A comparative study of preoperative color-coded Duplex ultrasonography versus handheld audible Dopplers in ALT flap planning.

INTRODUCTION: The anterior lateral thigh (ALT) flap's vascular variability can lead to complications. Thus, the accuracy of numerous planning modalities has been studied. The clinical relevance of competing mapping methods, however, remains unknown. Therefore, we compared the impact of color-coded Duplex ultrasonography and handheld audible Dopplers on surgical efficacy and flap safety. PATIENTS AND METHODS: Forty-four ALT flaps were included in this comparative retrospective monocentric study. Twelve patients received Duplex scans and 32 flaps were designed using Dopplers only. Patient, defect, and flap characteristics of both groups were analyzed. The effect of either planning method on the primary outcome variables - flap harvest and operative times (HT, OT), course of perforator dissection, incidence of flap loss, emergent re-explorations, and donor-site revisions - was then assessed. RESULTS: Patient, defect, and flap characteristics were comparable between both groups, including flap size (Doppler: 134 ± 73 cm2 , Duplex: 131 ± 65 cm2 , p = .90). There was no flap loss. Emergent re-explorations (Doppler: 4/32, Duplex: 1/12, p = .70) and donor-site revisions (Doppler: 2/32, Duplex: 1/12, p = .81) were equally distributed. Duplex rendered septal perforator dissection 10 times more likely (Chi-Square = 8.9, p = .003, OR = 9.7), reaching 50% (n = 6/12), as opposed to only 9% in the Doppler cohort (n = 3/32). This allowed for highly significant HT and OT reductions of 89 minutes, respectively (p < .01): from 255 and 383 min (Doppler) to 166 and 294 min (Duplex). CONCLUSIONS: Preoperative Duplex significantly reduces harvest and operative times of ALT flaps.

Concepts in Early Reconstruction of the Burned Hand.

BACKGROUND: Early reconstruction of burn sequelae of the hand can be challenging owing to high goals for functional and aesthetic outcome. A variety of reconstructive procedures with ascending levels of complexity exists and warrants careful indication. METHODS: In this case series, the main reconstructive techniques for reconstruction of burn defects of the hand are described, illustrated, and discussed: split thickness skin grafting (STSG) with fibrin glue, dermal matrices with STSG, distant random pattern (abdominal bridge) flap, distant pedicled flap (superficial circumflex iliac artery flap), and free microvascular tissue transfer (anterolateral thigh flap). An algorithm for decision making in the reconstructive process is proposed. RESULTS: Split thickness skin grafting provides sufficient coverage for partial thickness defects without exposure of functional structures; fixation with fibrin glue avoids unnecessary stapling. Dermal matrices under STSG provide vascularized granulation tissue on full thickness defects and can be used as salvage procedure on functional structures. Distant random pattern or pedicled flaps provide sufficient coverage of large full thickness defects with exposed functional structures but pose some challenges regarding patient compliance and immobilization. Free tissue transfer allows tailored reconstruction of large full thickness defects with exposed functional structures and can be safely and feasibly performed. Secondary and tertiary procedures are needed with more complex techniques; if applied correctly and consequently, all methods can yield favorable functional and aesthetic outcomes. CONCLUSIONS: Reconstruction of the burned hand may require a broad armamentarium of surgical techniques with different levels of complexity, versatility, and applicability. Excellent results can be achieved with the right procedure for the right patient.

Automatic bone segmentation in whole-body CT images.

PURPOSE: Many diagnostic or treatment planning applications critically depend on the successful localization of bony structures in CT images. Manual or semiautomatic bone segmentation is tedious, however, and often not practical in clinical routine. In this paper, we present a reliable and fully automatic bone segmentation in whole-body CT scans of patients suffering from multiple myeloma. METHODS: We address this problem by using convolutional neural networks with an architecture inspired by the U-Net [17]. In this publication, we compared three training procedures: (1) training from 2D axial slices, (2) a pseudo-3D approach including axial, sagittal and coronal slices and (3) an approach where the network is pre-trained in an unsupervised manner. RESULTS: We evaluated the method on an in-house dataset of 18 whole-body CT scans consisting of 6800 axial slices, achieving a dice score of 0.95 and an intersection over union (IOU) of 0.91. Furthermore, we evaluated our method on the dataset used by Peréz-Carrasco et al. (Comput Methods Progr Biomed 156:85-95, 2018). The data and the ground truth have been made publicly available. The proposed method outperformed the other methods, obtaining a dice score of 0.92 and an IOU of 0.85. CONCLUSION: These promising results could facilitate the evaluation of bone density and the localization of focal lesions in the future, with a potential impact on both disease staging and treatment planning.