Lumbar Artery Perforator Flaps in Autologous Breast Reconstruction.

The lumbar artery perforator (LAP) flap should be considered for autologous breast reconstruction when a patient's abdomen is unavailable as a donor site. The LAP flap can be harvested with dimensions and volume of distribution that facilitate the restoration of a naturally shaped breast with a sloping upper pole and maximal projection in the lower one-third. Harvest of LAP flaps lifts the buttocks and narrows the waist and, consequently, aesthetic improvement in body contour is generally achieved with these procedures. Although technically challenging, the LAP flap is a valuable tool in the practice of autologous breast reconstruction.

The Current State of Targeted Muscle Reinnervation: A Systematic Review.

BACKGROUND: Targeted muscle reinnervation (TMR) is growing in popularity; however, literature evaluating patient characteristics and outcomes is limited. METHODS: The EMBASE database was queried with the search terms "targeted muscle reinnervation" OR "TMR" AND "outcomes" OR "patient outcomes." Clinical human studies in English were eligible for inclusion, yielding 89 articles. After rigorous exclusion criteria, a total of 13 articles were included in this review. Study data including geographic location, patient demographics, TMR indication, amputation level, number of nerve transfers performed, length of follow-up, and reported outcomes were extracted and analyzed. RESULTS: The included articles represent 338 patients (341 limbs). Average patient age was 47.4 years. Indication for amputation included trauma (n = 125), infection (n = 76) cancer/tumor resection (n = 71), ischemia (n = 18), failed Charcot reconstruction (n = 15), failed hardware (n = 9), burn (n = 4), and CRPS (n = 4). Five studies included upper extremity TMR only, two included lower extremity TMR only, and six included both upper and lower extremity TMR. TMR was performed in an immediate or delayed fashion, with an average of 2.2 nerve transfers performed per limb overall. Average length of follow-up was 22.3 months. In three studies, patients with phantom limb pain undergoing delayed TMR were found to have significant or trending toward significant reduction in pain after TMR using numeric rating scale and patient-reported outcomes measurement information system scales. One article reported 9/10 patients with improved or complete resolution of phantom limb pain after delayed TMR. Three studies found that patients undergoing immediate TMR had lower pain scores compared with non-TMR controls. CONCLUSION: While there is evidence that TMR reduces neuroma-related pain and improves the quality of life for amputees, further outcomes studies are needed to study the patient experience with TMR on a larger scale. Establishing standardized, validated patient-reported outcomes assessment tools is critical to future investigation in this field.

Targeted muscle reinnervation: A narrative review of a novel tool for the management of neuropathic pathology in major lower extremity amputations.

OBJECTIVE: The purpose of this narrative review is to provide the vascular surgery community with updated recommendations and information regarding the use of Targeted Muscle Reinnervation (TMR) for both the prevention and treatment of chronic pain and phantom limb pain occurring in patients after undergoing lower extremity amputation for peripheral artery disease. METHODS: Current available literature discussing TMR is reviewed and included in the article in order to provide a succinct overview on the indications, clinical applications, and surgical technique for TMR. Additionally, early studies showing favorable long-term results after TMR are discussed. Patient consent for publication was obtained for this investigation. RESULTS: TMR has been demonstrated to be an effective means of both treating and preventing neuroma-related symptoms including chronic pain and phantom limb pain. It has been proven to be technically feasible, and can help patients to have improved utilization of prostheses for ambulation, which can conceivably lead to a reduction in mortality. CONCLUSIONS: TMR is an important tool to consider for any patient undergoing lower extremity amputation for a vascular-related indication. A vascular-plastic surgeon dual team approach is an effective means to prevent and reduce neuromas and associated chronic pain in this patient population.

Do larger reductions yield larger returns? patient-reported outcomes as a function of specimen weight in bilateral reduction mammoplasty.

BACKGROUND: Patients undergoing breast reduction mammoplasty for symptomatic macromastia have a significantly improved quality of life postoperatively. However, there are no data that examine the effect of reduction mammoplasty on quality of life as a function of the weight of tissue removed. Because the process by which insurance providers consider patients' candidacy for this breast reduction mammoplasty is most often based on the proposed weight of tissue to be removed, this gap in our understanding is particularly glaring. We therefore designed a prospective trial with the intent of investigating the correlation between breast reduction specimen weight and postoperative pain and quality of life. METHODS: After obtaining institutional review board (IRB) approval, patients presenting for breast reduction mammoplasty at a single academic medical center between January 2016 and September 2019 were prospectively enrolled in the study. Study participants completed the Numerical Pain Rating Scale (NPRS), the short-form McGill Pain Questionnaire (SF-MPQ), and the BREAST-Q at set time points (preoperatively, 1 week/1 month/3 months/6 months postoperatively). Patients were divided into three cohorts based on breast reduction specimen weights: small (<500 g reduction), intermediate (500-1000 g reduction), and large (>1000 g reduction). The surveys were then analyzed while controlling for demographic factors and complications. RESULTS: A total of 85 women were enrolled in the study and completed pre- and postoperative surveys (small reduction n = 21 (25%), intermediate n = 45 (53%), and large n = 19 (22%)). Regardless of reduction specimen weight, patients reported decreased overall pain and increased satisfaction with their breasts, as well as improved psychosocial, sexual, and physical well-being at each postoperative visit. Preoperative SF-MPQ pain scores were significantly lower in the small specimen weight group compared with either the intermediate or the large group (p = 0.001). Postoperatively, both the intermediate and large groups reported significant improvement in pain at each time point. The small specimen weight group did not report significant pain improvement until 3 months postoperatively. CONCLUSIONS: Patients undergoing breast reduction mammoplasty experience decreased pain and improved quality of life regardless of reduction specimen weight. Improvement in these parameters manifests as early as 1 week postoperatively and maintained at 3 months postoperatively. These data suggest that many patients who are denied coverage for reduction mammoplasty on the basis of low projected reduction specimen weight would derive significant benefit from the procedure.

A Systematic Review of the Utility of Indocyanine Angiography in Autologous Breast Reconstruction.

BACKGROUND: In the last decade, a number of studies have demonstrated the utility of indocyanine green (ICG) angiography in predicting mastectomy skin flap necrosis for immediate breast reconstruction. However, data are limited to investigate this technique for autologous breast reconstruction. Although it may have the potential to improve free flap outcomes, there has not been a large multicenter study to date that specifically addresses this application. METHODS: A thorough literature review based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines was conducted. All studies that examined the use of intraoperative ICG angiography or SPY to assess perfusion of abdominally based free flaps for breast reconstruction from January 1, 2000, to January 1, 2020, were included. Free flap postoperative complications including total flap loss, partial flap loss, and fat necrosis were extracted from selected studies. RESULTS: Nine relevant articles were identified, which included 355 patients and 824 free flaps. A total of 472 free flaps underwent clinical assessment of perfusion intraoperatively, whereas 352 free flaps were assessed with ICG angiography. Follow-up was from 3 months to 1 year. The use of ICG angiography was associated with a statistically significant decrease in flap fat necrosis in the follow-up period (odds ratio = 0.31, P = 0.02). There was no statistically significant difference for total or partial flap loss. CONCLUSIONS: From this systematic review, it can be concluded that ICG angiography may be an effective and efficient way to reduce fat necrosis in free flap breast reconstruction and may be a more sensitive predictor of flap perfusion than clinical assessment alone. Future prospective studies are required to further determine whether ICG angiography may be superior to clinical assessment in predicting free flap outcomes.

Revisiting the internal mammaries as recipient vessels in breast reconstruction: considerations in current practice.

BACKGROUND: The internal mammary artery (IMA) has supplanted the thoracodorsal artery as the primary recipient vessel in autologous breast reconstruction. Additionally, the IMA continues to be the preferred bypass graft choice in patients undergoing coronary artery bypass grafting (CABG). However, practice patterns in breast reconstruction have evolved considerably since the adoption of the IMA for this application. The authors sought to evaluate the safety of IMA harvest for breast reconstruction in our current practice, given the possibility that patients may require CABG in the future. METHODS: The authors reviewed the prospective database of free flaps for breast reconstruction performed at their center from 2009 to 2017. Patients were divided into three groups (2009-2011, 2011-2013, 2014-2017) and compared on the basis of demographics, medical comorbidities, and laterality of reconstruction. Patients were further risk stratified for 10-year risk of cardiovascular events using the American College of Cardiology's atheroscletoric and cardiovascular disease (ASCVD) risk calculator. RESULTS: There was a marked increase in the number of patients who underwent microsurgical breast reconstruction at our institution over the past three years (2009-2011, n = 55; 2012-2014, n = 50; 2015-2017, n = 145). The distribution of unilateral versus bilateral flaps changed meaningfully; however, they did not change statistically significantly over the study period (2009-2011 = 32.7%, 2012-2014 = 28.0%, 2015-2017 = 49.0%, p = 0.12). The rise in bilateral reconstructions over the study period is commensurate with the observed significant rise in contralateral prophylactic mastectomies (2009-2011 = 25.5%, 2012-2014 = 20.0%, 2015-2017 = 42.1%, p = 0.022). The mean 10-year risk of major cardiovascular events in the entire sample was 6.3 ± 7.1% (median 4.0%). The maximum individual risk score exceeded 25% in all three groups. CONCLUSION: Given overall trends in breast reconstruction and the sometimes-elevated cardiac risk profiles of our patients, the authors recommend risk stratification of all patients using the proposed Breast Reconstruction Internal Mammary Assessment (BRIMA) scoring system and consideration of left internal mammary artery preservation in select cases.

Estimation of Profunda Artery Perforator Flap Weight Using Preoperative Computed Tomography Angiography.

BACKGROUND: Given the relatively small size of thigh-based flaps and the possible necessity for a multiflap reconstruction, it is imperative to arrive at an accurate estimation of flap weight during preoperative planning. It was our objective to develop a novel technique for the preoperative estimation of profunda artery perforator (PAP) flap weight. METHODS: All patients that underwent transverse PAP flap breast reconstruction at two institutions were retrospectively reviewed. Subcutaneous tissue thicknesses were measured on axial computed tomography angiography scans at several predetermined points. The distance from the inferior gluteal crease to the PAP was also recorded. Linear regression was used to estimate flap weight. RESULTS: A total of 18 patients (32 flaps) were analyzed. The median intraoperative flap weight was 299 g (interquartile range [IQR]: 235-408). The parsimonious model (R 2 = 0.80) estimated flap weight using the Eq. 77.9x + 33.8y + 43.4z - 254.3, where x is subcutaneous tissue thickness (cm) at the lateral border of long head of the biceps femoris at a level 4.5 cm caudal to the inferior gluteal fold, y is distance (cm) from the inferior gluteal fold to the dominant PAP, and z has a value of 1 if the patient was scanned in the supine position or 0 if prone. The aforementioned formula yielded a median estimated flap weight of 305 g (IQR: 234-402) and a median percent error of 10.5% (IQR: 6.1-16.2). CONCLUSION: The authors demonstrate a simple and accurate formula for the preoperative estimation of transverse PAP flap weight for breast reconstruction.

Bipedicle-Conjoined Deep Inferior Epigastric Perforator Flaps for Unilateral Breast Reconstruction in Overweight and Obese Patients: Do the Benefits Outweigh the Risks?

BACKGROUND: Some surgeons have advocated for the use of bipedicle-conjoined deep inferior epigastric perforator (DIEP) flaps in unilateral autologous breast reconstruction in thin patients in whom a hemiabdominal flap is deemed insufficient. There have been no studies to date, however, exploring complication rates for bipedicle-conjoined DIEP flaps for unilateral reconstruction in overweight or obese patients. METHODS: The authors performed a retrospective review of two senior authors' patients from 2013 until 2018. In this time period, 71 patients underwent unilateral breast reconstruction with bipedicle-conjoined DIEP flaps. The patients were divided into normal weight (body mass index [BMI] < 25, n = 30), and overweight/obese (BMI > 25, n = 41) groups. Outcomes were reviewed for both major and minor complications. RESULTS: The average BMI of the normal group was 23.1 ± 1.3 kg/m2, while the average BMI of the overweight/obese group was 28.9 ± 4.0 kg/m2 (p < 0.01). There were no significant differences in demographics or comorbidities between the two groups.There were no statistically significant differences in the overall incidence of major or minor complications between the two groups (major: overweight/obese = 12.1%, normal BMI = 10.0%, p = 0.39; minor: overweight/obese = 39.0%, normal BMI = 36.7%, p = 0.47). The rate of moderate fat necrosis was significantly higher in the overweight/obese group (overweight/obese = 9.8%, normal BMI = 0%, p = 0.04). CONCLUSION: Unilateral breast reconstruction with bipedicle-conjoined DIEP flaps can be performed safely in overweight and obese patients. The use of bipedicle-conjoined DIEP flaps in this population allows surgeons to provide overweight or obese patients with reconstructions that are commensurate with their body habitus and/or contralateral breast.

Unilateral Autologous Breast Reconstruction with Bi-pedicled, Conjoined Deep Inferior Epigastric Perforator Flaps.

BACKGROUND: The abdomen remains the most popular and reliable donor site for autologous breast reconstruction. Some patients, however, lack sufficient tissue to recreate an aesthetic breast mound using a single-pedicle, deep inferior epigastric perforator (DIEP) flap, particularly when matching a contralateral native breast. The amount of abdominal skin and/or soft tissue reliably supplied by one vascular pedicle is frequently insufficient to adequately restore the breast skin envelope and "footprint." This study summarizes our experience with using bipedicled DIEP flaps to improve the aesthetic results of unilateral breast reconstruction in such patients. METHODS: Consecutive patients undergoing unilateral breast reconstruction with bi-pedicled, conjoined DIEP flaps over a 4-year period were retrospectively reviewed. Primary and secondary flap microvascular anastomoses were performed to the antegrade internal mammary (IM) vessels and to either the retrograde IM vessels or a primary DIEP pedicle side branch, respectively. Clinical characteristics and outcomes were recorded. RESULTS: Sixty-three patients underwent immediate (n = 29) or delayed (n = 34) reconstruction, with age and body mass index of 54.1 ± 8.4 years and 26.6 ± 4.7, respectively. Mean follow-up was 14.1 months. Twenty-eight (44.4%) patients received prereconstruction radiation therapy. All patients had preoperative abdominal imaging, including 57 (90.5%) using magnetic resonance angiography. There were no flap losses with three operative interventions for flap salvage. CONCLUSION: Unilateral breast reconstruction with bipedicled, conjoined DIEP flaps is safe and reliable. These procedures can be performed with a complication profile similar to single-pedicle DIEP flaps. The additional skin and soft tissue available with bi-pedicled flaps allows for greater flexibility in matching the shape and projection of a woman's contralateral breast, and in some cases is necessary to achieve an aesthetically acceptable reconstruction. With growing expectations among breast reconstruction patients, conjoined bi-pedicled flaps represent a tool for meeting their reconstructive needs and exceeding the status quo for aesthetic outcomes.

Risk Factors for Postoperative Venous Thromboembolic Complications after Microsurgical Breast Reconstruction.

BACKGROUND: Venous thromboembolism (VTE) is a significant cause of postoperative morbidity and a focus of patient safety initiatives. Despite giving appropriate prophylaxis in accordance with the Caprini risk assessment model, we observed a high incidence of VTE in patients undergoing microsurgical breast reconstruction at our institution. To explore factors contributing to these events, we compared patients undergoing microsurgical breast reconstruction who sustained postoperative VTEs to those who did not. METHODS: A retrospective review of all patients who underwent microsurgical free flap breast reconstruction at Montefiore Medical Center from January 2009 to January 2016 was conducted. Patients were divided into two cohorts; those sustaining postoperative VTE and those who did not. Patients were compared based on demographics, comorbidities, operative time, estimated intraoperative blood loss, need for transfusion, volume of transfusion, and discharge on postoperative aspirin. RESULTS: A total of 133 patients underwent microsurgical breast reconstruction during the study period. Nine patients (6.8%) had postoperative VTE and there was one (0.8%) death. Patients having VTE were more likely to be Hispanic (33.3%, n = 3) in the VTE group versus 8.1% (n = 6) in the control group (p = 0.011), more likely to have an increased mean transfusion volume (455.5 ± 367.8 vs. 139.51 ± 221.7 mL, p = 0.03), and were more likely to be discharged without aspirin (77.8%, n = 7 and 58.1%, n = 72; p = 0.003). CONCLUSION: Patients sustaining postoperative VTE after microsurgical breast reconstruction are more likely to have an increased volume of blood transfusions and lack of discharge on postoperative aspirin.

Lacunocanalicular fluid flow transduces mechanical tension stress during distraction osteogenesis.

The mechanotransduction mechanisms linking distraction device activation to new bone formation remain unknown. We hypothesize that the tension stress of activation during distraction osteogenesis is transmitted through lacunocanalicular fluid flow to initiate the osteogenic signaling cascade. Adult Sprague-Dawley rats (N = 24) were subjected to mandibular osteotomy and application of an external distraction device. After a 3-day latency period, half the animals (n = 12) underwent device activation at 0.25 mm twice daily for 6 days (total activation, 3 mm), and the other half (n = 12) had no activation. On day 10, the animals were injected with fluorescent reactive red lacunocanalicular tracer before killing. Mandibles were harvested, embedded, and sectioned, and reactive red epifluorescence lacunocanalicular flow was measured. Protein was harvested for focal adhesion kinase 1 (FAK1), NESPRIN1, SUN1, LAMIN A/C, and SMAD1 Western blotting as well as for bone morphogenetic protein (BMP)-2 enzyme-linked immunosorbent assay and alkaline phosphatase assay. Lacunocanalicular fluid flow was significantly greater in the distracted samples (60.5 ± 14 vs 10.3 ± 4 molecules of equivalent soluble fluorochrome per megapixel, P = 0.01). Flow distribution demonstrated the highest lacunocanalicular flow near the center of the distraction gap. Increased lacunocanalicular flow resulted in increased FAK1 (P = 0.009), NESPRIN1 (P = 0.01), SUN1 (P = 0.01), and LAMIN A/C (P = 0.008) expression. Focal adhesion kinase 1 activation in the presence of BMP-2 protein expression (P = 0.001) resulted in increased intranuclear SMAD1 phosphorylation (P = 0.04) and alkaline phosphatase activity (P < 0.0001). These findings suggest that activation of the distraction osteogenesis device affects cellular response through changes in lacunocanalicular fluid flow.

Endogenous stem cell therapy enhances fat graft survival.

BACKGROUND: Lipoaspirate centrifugation creates graded density of adipose tissue. High-density fat contains more vasculogenic cytokines and progenitor cells and has greater graft survival than low-density fat. The authors hypothesize that accelerating the bone marrow-derived progenitor cell response to injected low-density fat will improve its graft survival. METHODS: Male 8-week-old FVB mice (n=60) were grafted with either high-density (n=20) or low-density (n=40) human lipoaspirate. Half of the mice receiving low-density fat (n=20) were treated with a stem cell mobilizer for 14 days. Grafted fat was harvested at 2 and 10 weeks for analysis. RESULTS: Low-density fat, low-density fat plus daily AMD3100, and high-density fat had 26±3.0, 61.2±7.5, and 49.6±3.5 percent graft survival, respectively, at 2 weeks (low-density fat versus low-density fat plus daily AMD3100 and low-density fat versus high-density fat, both p<0.01). Similar results were observed 10 weeks after grafting. Mice receiving low-density fat plus daily AMD3100 had significantly more vasculogenic progenitor cells per cubic centimeter of peripheral blood (p<0.01) and more new blood vessels (p<0.01). Both low-density fat plus daily AMD3100 and high-density fat contained more stromal-derived factor-1α and vascular endothelial growth factor mRNA/protein. CONCLUSION: Endogenous progenitor cell mobilization enhances low-density fat neovascularization, increases vasculogenic cytokine expression, and improves graft survival to a level equal to that of high-density fat grafts.

Fat grafting accelerates revascularisation and decreases fibrosis following thermal injury.

BACKGROUND: Fat grafting has been shown clinically to improve the quality of burn scars. To date, no study has explored the mechanism of this effect. We aimed to do so by combining our murine model of fat grafting with a previously described murine model of thermal injury. METHODS: Wild-type FVB mice (n=20) were anaesthetised, shaved and depilitated. Brass rods were heated to 100°C in a hot water bath before being applied to the dorsum of the mice for 10s, yielding a full-thickness injury. Following a 2-week recovery period, the mice underwent Doppler scanning before being fat/sham grafted with 1.5cc of human fat/saline. Half were sacrificed 4 weeks following grafting, and half were sacrificed 8 weeks following grafting. Both groups underwent repeat Doppler scanning immediately prior to sacrifice. Burn scar samples were taken following sacrifice at both time points for protein quantification, CD31 staining and Picrosirius red staining. RESULTS: Doppler scanning demonstrated significantly greater flux in fat-grafted animals than saline-grafted animals at 4 weeks (fat=305±15.77mV, saline=242±15.83mV; p=0.026). Enzyme-linked immunosorbent assay (ELISA) analysis in fat-grafted animals demonstrated significant increase in vasculogenic proteins at 4 weeks (vascular endothelial growth factor (VEGF): fat=74.3±4.39ngml(-1), saline=34.3±5.23ngml(-1); p=0.004) (stromal cell-derived factor-1 (SDF-1): fat=51.8±1.23ngml(-1), saline grafted=10.2±3.22ngml(-1); p<0.001) and significant decreases in fibrotic markers at 8 weeks (transforming growth factor-ß1(TGF-ß): saline=9.30±0.93, fat=4.63±0.38ngml(-1); p=0.002) (matrix metallopeptidase 9 (MMP9): saline=13.05±1.21ngml(-1), fat=6.83±1.39ngml(-1); p=0.010). CD31 staining demonstrated significantly up-regulated vascularity at 4 weeks in fat-grafted animals (fat=30.8±3.39 vessels per high power field (hpf), saline=20.0±0.91 vessels per high power field (hpf); p=0.029). Sirius red staining demonstrated significantly reduced scar index in fat-grafted animals at 8 weeks (fat=0.69±0.10, saline=2.03±0.53; p=0.046). CONCLUSIONS: Fat grafting resulted in more rapid revascularisation at the burn site as measured by laser Doppler flow, CD31 staining and chemical markers of angiogenesis. In turn, this resulted in decreased fibrosis as measured by Sirius red staining and chemical markers.

Augmenting neovascularization accelerates distraction osteogenesis.

BACKGROUND: Distraction osteogenesis has revolutionized the treatment of craniofacial deformities, but it is limited by lengthy consolidation periods and tenuous healing in certain clinical settings, such as irradiated tissue. In this study, the authors aim to investigate whether increasing neovascularization by progenitor cell mobilization accelerates bone formation during distraction. METHODS: Sprague-Dawley rats aged 8 weeks (n = 36) were subjected to unilateral mandibular distraction with 3-day latency, 7-day activation (0.25 mm twice daily), and 21-day consolidation periods. From the beginning of the consolidation period, animals received daily injections of either AMD3100 (bone marrow progenitor cell mobilizing agent) or sterile saline. Animals were euthanized on postoperative day 31; mandibles were harvested; and bone regeneration was assessed using micro-computed tomography, immunohistochemistry, bone morphogenetic protein-2 enzyme-linked immunosorbent assay, and mechanical testing. RESULTS: Immunohistochemistry demonstrated that AMD3100 treatment increased vascular density and bone formation. Micro-computed tomography and dual-emission x-ray absorptiometry demonstrated that AMD3100-treated animals had improved bone generation compared with sham-treated controls. Greater force was required on three-point testing to break AMD3100-treated bone. Bone morphogenetic protein-2 expression was up-regulated with AMD3100. Interestingly, the nondistracted contralateral hemimandibles treated with AMD3100 were also stronger than sham-treated counterparts. CONCLUSIONS: Progenitor cell mobilization improves bone regeneration in a rat distraction model. Furthermore, because this effect is seen in healthy bone and in ischemic bone healing during distraction, the mechanism is not merely related to oxygenation, but could be a phenomenon of fluid flow.

Interval cranioplasty: comparison of current standards.

BACKGROUND: Although different cranioplasty storage methods are currently in use, no study has prospectively compared these methods. The authors compare freezing and subcutaneous storage methods in a rat model. METHODS: Trephine defects (10 mm) were created in 45 Sprague-Dawley rats. The cranial bone grafts were stored in an autologous subcutaneous pocket (n = 15), frozen at -80°C (n = 15), immediately analyzed (n = 12), or immediately replanted into the defect (n = 3). After 10 days of storage, the subcutaneous or frozen grafts were either replanted (subcutaneous, n = 3; frozen, n = 3) or analyzed (subcutaneous, n = 12; frozen, n = 12). Grafts underwent histologic analysis, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase assay, mechanical testing, and micro-computed tomographic imaging. RESULTS: After 10 days of storage, physiologic assays demonstrated a significant decrease in cellular functionality (e.g., alkaline phosphatase assay concentration: fresh, 18.8 ± 0.77 mM/mg; subcutaneous, 12.2 ± 0.63 mM/mg; frozen, 8.07 ± 1.1 mM/mg; p < 0.012 for all comparisons). Mechanical integrity (maximal load) of fresh grafts was greatest (fresh, 9.26 ± 0.29 N; subcutaneous, 6.27 ± 0.64 N; frozen, 4.65 ± 0.29 N; fresh compared with frozen, p < 0.001; fresh compared with subcutaneous, p = 0.006). Replantation of subcutaneously stored and frozen grafts resulted in limited bony union and considerable resorption after 12 weeks; in contrast, replanted fresh grafts demonstrated bony union and little resorption. CONCLUSIONS: Current preservation methods for interval cranioplasty do not maintain bone graft viability. Subcutaneous storage appears to provide a small advantage compared with freezing.

Human fat grafting alleviates radiation skin damage in a murine model.

BACKGROUND: Autogenous fat grafting has been observed to alleviate the sequelae of chronic radiodermatitis. To date, no study has replicated this finding in an animal model. METHODS: The dorsa of adult wild-type FVB mice were shaved and depilated. The dorsal skin was then distracted away from the body and irradiated (45 Gy). Four weeks after irradiation, 1.5-cc fat or sham grafts were placed in the dorsal subcutaneous space. Gross results were analyzed photometrically. The animals were euthanized at 4 and 8 weeks after fat or sham grafting and their dorsal skin was processed for histologic analysis. RESULTS: Hyperpigmentation and ulceration were grossly improved in fat-grafted mice compared with sham-grafted controls. This improvement manifested histologically in a number of ways. For example, epidermal thickness measurements demonstrated decreased thickness in fat-grafted animals at both time points (20.6 ± 1.5 µm versus 55.2 ± 5.6 µm, p = 0.004; 17.6 ± 1.1 µm versus 36.3 ± 6.1 µm, p = 0.039). Picrosirius red staining demonstrated a diminished scar index in fat-treated animals at both time points as well (0.54 ± 0.05 versus 0.74 ± 0.07, p = 0.034; and 0.55 ± 0.06 versus 0.93 ± 0.07, p = 0.001). CONCLUSION: Fat grafting attenuates inflammation in acute radiodermatitis and slows the progression of fibrosis in chronic radiodermatitis.