Functional outcomes of reconstructive flap surgery for soft tissue sarcoma: Long-term outcomes of functional restoration using innervated muscle transplantation.

Functional outcomes associated with prognostic factors and innervated muscle transplantation after wide soft tissue sarcoma resection remain unclear. We retrospectively examined the functional outcomes of reconstructive flap surgery for soft tissue sarcoma. Twenty patients underwent innervated muscle transplantation with pedicled or free flaps for functional reconstruction of resected muscles. Thirteen latissimus dorsi muscles and one vastus lateralis muscle combined with an anterolateral thigh flap were transferred as free flaps using the epi-perineural suture technique. Six latissimus dorsi muscles were transferred as pedicled flaps with neural continuity. Postoperative functional outcomes were assessed using the Musculoskeletal Tumor Society (MSTS) scores for the upper and lower extremities of 22 and 24 patients, respectively. The mean MSTS score for all patients was 82.3 at 12 months postoperatively. The mean scores for patients who underwent reconstruction with pedicled and free flaps were 89.2 and 77.1, respectively. The MSTS scores for the lower extremity, tumor size ≥5 cm, and free flap reconstruction were significantly lower than those for the upper extremity, tumor size <5 cm, and pedicled flap reconstruction (P = 0.02, 0.37, and 0.008, respectively). The postoperative MSTS score for innervated muscle transplantation was 76.7 at 12 months and was significantly higher (83.7) at 24 months (P = 0.003). Functional outcomes were significantly associated with tumor location, tumor size, and reconstructive flap type based on the MSTS scores. Innervated muscle transplantation improved functional outcomes at 24 months postoperatively via sufficient recovery of the innervated muscle, not the compensatory recovery of the remaining muscle.

Effect of joint limitation and balance control on gait changes in diabetic peripheral neuropathy.

Aims: This study analyzed the gait patterns of diabetic peripheral neuropathy (DPN) patients and changes in the center of mass sway to prevent the formation and recurrence of foot ulcers. Methods: Forty-two subjects were divided into the diabetes mellitus (DM), DPN, and diabetic foot ulcer (DFU) groups. We measured the range of motion (ROM) of the lower limb joints in the resting position and the center of mass sway in the standing position. Joint angles, ROM during walking, and distance factors were evaluated. Results: In the DFU group, ROM limitation during walking was detected at the knee joint, and functional and ROM limitations were found at the ankle joint. The step length ratio and step width in the DFU group were significantly lower and higher than those in the DM group, respectively. The sway distances in the DFU group were greater than those in the DM and DPN groups. Conclusions: Functional joint limitations and gait changes due to the decreased ability to maintain the center of gravity were observed in the DFU group. As DPN progressed, the patients' gait became small, wide, and shuffled. Thus, supporting joint movement during walking may help reduce the incidence and recurrence of foot ulcers. Supplementary Information: The online version contains supplementary material available at 10.1007/s13340-023-00647-9.

Risk factors for early wound dehiscence by surgical site infection after pressure ulcer surgery.

AIMS: The most common postoperative complication when treating a pressure ulcer with a flap or primary closure is early wound dehiscence. In this study, we aimed to investigate the cause of early wound dehiscence and its associated risk factors. Early wound dehiscence was defined as the wound dehiscence within the post operation period where no weight or tension is applied to the wound. METHODS: We conducted a retrospective study of 40 patients with pressure ulcers (69 sites). We calculated the significant difference in the incidence of wound dehiscence between the groups for the following 15 factors : age, obesity, emaciation, diabetes mellitus, smoking, ulcer site, musculocutaneous flap, methicillin-resistant Staphylococcus aureus, presence of two or more types of bacteria, albumin level, C-reactive protein level, white blood cell count, hemoglobin level, operative time, and ulcer size. RESULTS: Bacteria were detected in all wounds with early dehiscence, which was found in 28 (40.6%) of the 69 cases. C-reactive protein level, albumin level, musculocutaneous flap, and operative time were found to be risk factors for early wound dehiscence using the χ2-test and t-test. (P?=?0.011, 0.045, 0.018, and 0.003, respectively). CONCLUSION: The cause of dehiscence was considered to be surgical site infection. C-reactive protein level, albumin level, musculocutaneous flap, and operative time may be risk factors of the occurrence of early wound dehiscence. J. Med. Invest. 70 : 101-104, February, 2023.

Cyclical Stretching Induces Excess Intracellular Ca2+ Influx in Human Keloid-Derived Fibroblasts In Vitro.

BACKGROUND: The incidence of keloids is higher in the case of darker skin. It is more common in the parts exposed to stretching (thorax, abdomen, and joints). Cyclical stretching reportedly induced each Ca2+ spike through differential mechanosensitive channels in human synovial and dermal fibroblasts. Therefore, the authors hypothesized that cyclical stretching also induces a specific Ca2+ spike in keloid-derived fibroblasts. METHODS: This in vitro study compared the intracellular calcium dynamics induced by cyclical stretching between control (human dermal fibroblasts) and keloid (human keloid-derived fibroblasts) groups. Each group was exposed to two-dimensional stretch using an originally developed stretch microdevice. Intracellular Ca2+ was observed for 5 minutes, including 30 seconds of baseline, under a fluorescent confocal laser microscope. The intracellular Ca2+ concentration was evaluated every 0.5 second using the fluorescence intensity ratio. A positive cellular response was defined as a rise of the ratio by greater than or equal to 20%. The normal response cutoff value was determined by receiver operating characteristic analysis. RESULTS: The keloid groups were significantly more responsive than the control groups (15.7% versus 8.2%; P = 0.029). In the cellular response-positive cells, the keloid groups reached significantly higher intracellular Ca2+ concentration peaks than the control groups (2.20 versus 1.26; P = 0.0022). The cutoff value was 1.77, and 10.4% of the keloid-derived fibroblasts exhibited a hyper-Ca2+ spike above the normal range. CONCLUSIONS: Keloid-derived fibroblasts with a hyper-Ca2+ spike might constitute a keloid-specific subpopulation. Hereafter, the authors will study whether the normalization of excessive intracellular Ca2+ concentration leads to keloid treatment in vivo. CLINICAL RELEVANCE STATEMENT: This study result provided a clue to the onset mechanism of keloids, which the authors hope will lead to the development of new therapy in the future.

Relationship between fluctuations in skin perfusion pressure values and wound healing in patients with chronic limb-threatening ischemia undergoing hemodialysis.

Background : Patients with chronic limb-threatening ischemia are often on hemodialysis. It is unclear which skin perfusion pressure (SPP) values, i.e., those measured immediately after hemodialysis on a hemodialysis day or those measured on a non-hemodialysis day, reflect the actual wound healing course in chronic limb-threatening ischemia. Methods : Eighteen patients undergoing hemodialysis (49 measurements) who were treated for leg ulcers due to critical limb ischemia were included in the study. The SPP values were divided into two groups : those measured immediately after hemodialysis (HD day group) and those measured on non-hemodialysis days (non-HD day group). The wound healing outcomes were investigated. The cutoff SPP value for predicting wound healing was set to ≥ 35 mmHg. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SPP in each group were measured. The relationship between SPP and blood pressure was analyzed by regression analysis. Results : Significant differences were observed in the positive predictive value (HD day : 100%, non-HD day : 50% ; P = 0.002), The correlation coefficient was 0.698 in the HD day group and 0.292 in the non-HD day group. Diastolic blood pressure had a significant effect on SPP (P = 0.039). Conclusions : The measurements are best taken immediately after hemodialysis for more accuracy. J. Med. Invest. 69 : 294-298, August, 2022.

Radiographic Study Evaluating Perforator Vessels in the Ischiorectal Fossa for Safe Elevation of Island Flaps.

Perforator flaps based on the ischiorectal fossa (IRF) (ie, internal pudendal artery perforator flaps) are useful for perineal reconstruction. The three-dimensional characterization of perforator arteries in the IRF remains unclear, as the IRF contains thick adipose tissue as well as organs, such as the rectum, vagina, and urethra. This study aimed to evaluate perforators in the IRF to guide the safe elevation of skin flaps designed based on the IRF. Methods: IRF vessels were examined in 200 bilateral computed tomography angiography scans performed in 100 patients. We examined branching patterns arising from the internal iliac artery and the origins of the skin perforators in the IRF. Results: The branching patterns of the internal iliac artery were divided into three groups: perforators derived exclusively from the internal pudendal artery (78%), perforators derived from the internal pudendal artery and the inferior gluteal artery (18%), and perforators derived exclusively from the inferior gluteal artery (4%). The average number of perforators in the IRF was 1.5 ± 0.7. The number of perforators was significantly higher in women than in men. The perforator arteries were found exclusively around the medial and dorsal sides of the ischial tuberosity. Conclusions: We found that perforators in the IRF were stable. All cases had more than one skin perforator, which was mainly derived from the internal pudendal artery. Although perforators cannot be identified during flap elevation because the fatty tissue in the IRF is very thick, physicians must focus on preserving the perforator-containing fatty tissue around the ischial tuberosity.

Lateral Nasal Artery Perforator Flap for Nasal Reconstruction: Clinical Applications and Risk Factors Associated With Nasal Deformities.

BACKGROUND: Nasal reconstruction is challenging because of the difficulty in balancing superior aesthetic outcomes and less invasive surgery. The use of the lateral nasal artery (LNA) perforator flap has been reported for nasal reconstruction. However, few reports have described appropriate applications of nasal reconstruction and assessments of nasal deformity. This study aimed to quantify the aesthetic outcomes on using this flap and reveal the risk factors associated with nasal deformities. METHODS: Twenty patients underwent nasal reconstruction using the LNA flap with a cranial perforator adjacent to the nasal defect. Postoperative protuberant deformities were scored by 2 independent plastic surgeons using a 5-point Likert scale and classified as excellent, good, or poor. The risk factors of deformities were identified using univariate analyses. A nasal alar deviation index was developed to analyze correlations with flap harvesting. The sensory function was assessed by the Semmes-Weinstein test. RESULTS: Flaps survived in 19 patients (95%), and 1 flap showed distal necrosis. All arterial perforators used remained within 5 mm lateral to the boundary between the cheek and nasal ala. The flaps were most often used to cover 2 subunits, including the nasal sidewall defects. Protuberant deformities in 6 (30%), 8 (40%), and 6 (30%) patients were classified as excellent, good, and poor, respectively. Nasal defects involving more than 3 subunits caused severe protuberant deformity. Only 2 patients (5%) in the good and fair groups underwent additional debulking surgery. Nasal alar deviation was not significantly correlated with flap harvesting, when the nasal alar deviation index before and after surgery were compared. Sensory function was retained in all patients. CONCLUSIONS: Aesthetic outcomes and sensory function were good on using the LNA perforator flap as a propeller flap having a wide arc of rotation. This flap is suitable for nasal reconstruction involving less than 2 nasal subunits without any severe nasal alar deviation deformity. In addition, this flap allows for better outcomes because it requires less invasive 1-stage surgery.

Analysis of Risk Factors Associated With Drooping Deformity After Lower Eyelid Reconstruction: A Newly Developed Drooping Index.

BACKGROUND: Lower eyelid reconstruction is challenging because of the risk of severe postreconstruction deformities of the lower eyelid, such as drooping, entropion, and ectropion. However, the risk factors for these postreconstruction deformities are unclear. The present study aimed to quantify the drooping deformity of the lower eyelid after reconstruction using a cheek rotation flap and to identify risk factors associated with postreconstruction deformities. METHODS: Our study group included 28 patients who underwent full-thickness lower eyelid reconstruction using a cheek rotation flap for anterior lamella reconstruction. We developed the drooping index to classify postreconstruction outcomes as good (index <1.2), fair (index between 1.2 and 1.5), and poor (index >1.5). We identified risk factors for a drooping deformity using univariate analyses (Mann-Whitney U or Spearman rank correlation, depending on data distribution). RESULTS: Overall, the drooping index ranged between 1.0 and 2.11, with an average value of 1.3. A good outcome was obtained in 11, a fair outcome in 12, and a poor outcome in 5 patients. Clinically severe ectropion was observed in five of the 17 patients in the fair and poor outcome groups, with four of these patients requiring revision surgery. Risk factors for postreconstruction drooping deformity included medial location of the tumor, resection involving more than 50% of the horizontal width of the lower eyelid, and dissection of subcutaneous tissue of the cheek extending below the zygomatic arch. CONCLUSIONS: A cheek rotation flap provides satisfactory outcomes for full-thickness reconstruction of the lower eyelid. Extension of dissection of subcutaneous tissue of the cheek below the zygomatic arch increases the risk of postsurgical drooping deformity. Our drooping index provides a quantitative measure of drooping deformity and is clinically useful to classify outcomes.

The perifascial areolar tissue and negative pressure wound therapy for one-stage skin grafting on exposed bone and tendon.

BACKGROUND: Factors such as exposed bones or tendons can inhibit wound healing and make it a lengthy process unless aggressive debridement or vascularized flap surgery are performed. We have developed a new procedure involving simultaneous application of a skin graft and perifascial areolar tissue (PAT) and negative pressure wound therapy. METHODS: Of 8 patients with wounds, bones, tendons, and thick fascia were exposed in 4, 2, and 2 cases, respectively. These wounds were adequately covered with PAT, and split-thickness skin grafts were applied simultaneously on the PAT with a VACsize 4.9 bigcirc size 3.5 back 115 up 4 roman R device. RESULTS: In 6 of 8 cases, the skin graft and PAT were successful, and epithelialization was achieved within 4 weeks. PAT adapted but skin graft was unsuccessful in one case, and both the skin graft and PAT failed to adapt of a pressure ulcer. Using the PAT to overlap more than 400% of the exposed areas resulted in better adaptation. CONCLUSIONS: This procedure contributed to reducing the burden on the patients because we were able to use a skin graft on the exposed areas, without the need for removal of bone or tendons. This potentially means patients avoid loss of function in the affected areas and achieve better outcomes. J. Med. Invest. 65:96-102, February, 2018.

Risk factors for delayed healing at the free anterolateral thigh flap donor site.

BACKGROUND: The free anterolateral thigh (ALT) flap has been widely used for various kinds of reconstructions. However, delayed healing at the donor site occasionally occurs due to wound dehiscence or the partial loss of grafted skin at the donor site. The aim of the present study was to identify reliable predictive factors for delayed healing at the donor site after the harvest of a free ALT flap. METHODS: This study included 52 patients who underwent reconstructive procedures using free ALT flaps. The delayed healing group included patients with wounds at the donor site that had not healed over 3 weeks after surgery, and the normal healing group included patients who showed wound healing within 3 weeks after surgery. Multivariate logistic regression models were created to identify the risk factors for delayed healing at the ALT flap donor site. RESULTS: Among the 52 patients, 24 (46.2%) showed delayed healing at the donor site, and 6 patients required additional operative treatment. A high preoperative body mass index (BMI), smoking, and skin grafting were found to be significantly associated with delayed healing at the ALT donor site. Of the 37 patients who underwent skin grafting, 23 (62%) experienced delayed healing at the donor site. CONCLUSIONS: A high preoperative BMI, smoking, and skin grafting were risk factors for delayed healing at the free ALT donor site. Skin grafting at the ALT donor site should be avoided in patients with a high BMI or a habit of smoking.

An injectable non-cross-linked hyaluronic-acid gel containing therapeutic spheroids of human adipose-derived stem cells.

For chronic wounds, the delivery of stem cells in spheroidal structures can enhance graft survival and stem cell potency. We describe an easy method for the 3D culture of adipose-derived stem/stromal cells (ASCs) to prepare a ready-to-use injectable. We transferred suspensions of monolayer-cultured ASCs to a syringe containing hyaluronic acid (HA) gel, and then incubated the syringe as a 3D culture vessel. Spheroids of cells formed after 12 h. We found that 6 × 106 ASCs/ml in 3% HA gel achieved the highest spheroid density with appropriate spheroid sizes (20-100 µm). Immunocytology revealed that the stem cell markers, NANOG, OCT3/4, SOX-2, and SSEA-3 were up-regulated in the ASC spheroids compared with those in nonadherent-dish spheroids or in monolayer cultured ASCs. In delayed wound healing mice models, diabetic ulcers treated with ASC spheroids demonstrated faster wound epithelialization with thicker dermis than those treated with vehicle alone or monolayer cultured ASCs. In irradiated skin ulcers in immunodeficient mice, ASC spheroids exhibited faster healing and outstanding angiogenic potential partly by direct differentiation into α-SMA+ pericytes. Our method of 3D in-syringe HA gel culture produced clinically relevant amounts of ready-to-inject human ASC microspheroids that exhibited superior stemness in vitro and therapeutic efficacy in pathological wound repair in vivo.

Blood Congestion Can Be Rescued by Hemodilution in a Random-Pattern Skin Flap.

BACKGROUND: There is no standard method to ensure survival of random-pattern skin flaps. The authors developed a rat anemia model to observe survival of random-pattern skin flaps after blood transfusion and hemodilution. METHODS: Anemia was induced by withdrawal of 35 percent blood volume followed by compensation with the same amount of blood (blood transfusion model) or plasma equivalent (normovolemic hemodilution). Control rats were subjected to a sham procedure. Subsequently, a random-pattern skin flap (1.5 × 6 cm) was elevated on the back of each rat. Physiologic assessments of flap vascularity/viability were performed using laser Doppler spectrophotometry before and after flap elevation. RESULTS: The normovolemic hemodilution group showed anemia (hemoglobin, 9.5 ± 0.8 g/dl) but less flow occlusion and greater flap survival (72.8 ± 8.6 percent) compared with control (57.4 ± 9.6 percent; p < 0.01) and blood transfusion (62.1 ± 6.5 percent; p < 0.089) groups. In control and blood transfusion groups but not the normovolemic hemodilution group, blood flow was decreased and relative quantity of hemoglobin was increased toward the flap tip, indicating congestion. In control and blood transfusion groups, blood flow and tissue oxygen saturation dropped after flap elevation, but recovered by day 7; congestion gradually improved by day 7. CONCLUSIONS: The authors determined that congestion promoted necrosis and hemodilution reduced microcirculatory occlusion and increased blood flow and oxygenation in skin flaps. It was suggested that perioperative hemodilution is superior to blood transfusion in any flap operations unless there is a critical systemic need for blood transfusion.

Development of Skin Flaps for Reconstructive Surgery: Random Pattern Flap to Perforator Flap.

Flap transplantation has been an important procedure in plastic and reconstructive surgery to cover and fill various defects. Flap necrosis due to blood circulation failure leads to severe complications, especially in a patient undergoing reconstruction concerning the body cavity after tumor ablation. Surgical procedures for flap transplantation have been further improved and developed. We have reviewed from the random pattern flap to the newest procedure, the perforator flap. Perforator vessels were investigated in the process of development of the fasciocutaneous flap and have become important for blood supply of the skin flap. Blood circulation of the flap has become more stable and reliable than ever with the development and findings of the perforator vessels. Further development of a skin flap will be based on the perforasome concept, which involves the study of the territory and linking of perforator vessels. J. Med. Invest. 63: 159-162, August, 2016.

Reduction mammaplasty and mastopexy for the contralateral breast after reconstruction surgery following cancer resection: A report of 3 cases.

BACKGROUND: Breast reconstruction generally involves autologous tissue transplantation and placement of a mammary prosthesis. When the patient's breasts are extremely large and ptotic, breast reconstruction often results in significantly asymmetrical appearance. However, a good aesthetic outcome after reconstruction surgery following cancer resection is an important quality-of-life factor. We evaluated the efficacy of touch-up surgery, either reduction mammaplasty or mastopexy, performed on the contralateral breast for symmetrization. METHODS: Reduction mammaplasty was performed on the contralateral breast in 2 patients and mastopexy was performed on the contralateral breast in 1 patient after reconstruction surgery following cancer resection, between 2008 and 2014. We reviewed each patient's medical record for general clinical information and for the methods of breast cancer resection and breast reconstruction used, wait time between breast cancer resection and touch-up surgery, preservation of the sensitivity of the nipple-areola complex after the touch-up surgery, and aesthetic outcome (based on visual analog scale score). RESULTS: Wait times in the 3 cases were 4, 9, and 18 months. Nipple-areolar sensitivity was well preserved in all 3 cases. Aesthetic outcomes were judged "excellent" or "very good." CONCLUSION: Revision surgery on the contralateral breast 4 to 18 months after breast reconstruction substantially improves the aesthetic outcome. J. Med. Invest. 63: 281-285, August, 2016.

Therapeutic Potential of Human Adipose-Derived Stem/Stromal Cell Microspheroids Prepared by Three-Dimensional Culture in Non-Cross-Linked Hyaluronic Acid Gel.

UNLABELLED: Three-dimensional culture of mesenchymal stem/stromal cells for spheroid formation is known to enhance their therapeutic potential for regenerative medicine. Spheroids were prepared by culturing human adipose-derived stem/stromal cells (hASCs) in a non-cross-linked hyaluronic acid (HA) gel and compared with dissociated hASCs and hASC spheroids prepared using a nonadherent dish. Preliminary experiments indicated that a 4% HA gel was the most appropriate for forming hASC spheroids with a relatively consistent size (20-50 µm) within 48 hours. Prepared spheroids were positive for pluripotency markers (NANOG, OCT3/4, and SOX-2), and 40% of the cells were SSEA-3-positive, a marker of the multilineage differentiating stress enduring or Muse cell. In contrast with dissociated ASCs, increased secretion of cytokines such as hepatocyte growth factor was detected in ASC spheroids cultured under hypoxia. On microarray ASC spheroids showed upregulation of some pluripotency markers and downregulation of genes related to the mitotic cell cycle. After ischemia-reperfusion injury to the fat pad in SCID mice, local injection of hASC spheroids promoted tissue repair and reduced the final atrophy (1.6%) compared with that of dissociated hASCs (14.3%) or phosphate-buffered saline (20.3%). Part of the administered hASCs differentiated into vascular endothelial cells. ASC spheroids prepared in a HA gel contain undifferentiated cells with therapeutic potential to promote angiogenesis and tissue regeneration after damage. SIGNIFICANCE: This study shows the therapeutic value of human adipose-derived stem cell spheroids prepared in hyarulonic acid gel. The spheroids have various benefits as an injectable cellular product and show therapeutic potential to the stem cell-depleted conditions such as diabetic chronic skin ulcer.

Micronized cellular adipose matrix as a therapeutic injectable for diabetic ulcer.

BACKGROUND: Despite the clinical potential of adipose-derived stem/stromal cells (ASCs), there are some clinical difficulties due to the regulation of cell therapies. MATERIALS & METHODS: Micronized cellular adipose matrix (MCAM) injectable was prepared through selective extraction of connective tissue fractions in fat tissue only through mechanical minimal manipulation procedures. RESULTS: It retained some capillaries and ASCs, but most adipocytes were removed. The presence of viable ASCs, vascular endothelial cells was confirmed and ASCs of MCAM kept intact mesenchymal differentiation capacity. In diabetic mice, skin wounds treated with MCAM showed significantly accelerated healing compared with phosphate-buffered saline-treated ones. CONCLUSION: The proven potential of MCAM to accelerate healing in ischemic diabetic ulcers may offer a simple, safe and minimally invasive means for tissue repair and revitalization.

Therapeutic Potential of Adipose-Derived SSEA-3-Positive Muse Cells for Treating Diabetic Skin Ulcers.

Stage-specific embryonic antigen-3 (SSEA-3)-positive multipotent mesenchymal cells (multilineage differentiating stress-enduring [Muse] cells) were isolated from cultured human adipose tissue-derived stem/stromal cells (hASCs) and characterized, and their therapeutic potential for treating diabetic skin ulcers was evaluated. Cultured hASCs were separated using magnetic-activated cell sorting into positive and negative fractions, a SSEA-3+ cell-enriched fraction (Muse-rich) and the remaining fraction (Muse-poor). Muse-rich hASCs showed upregulated and downregulated pluripotency and cell proliferation genes, respectively, compared with Muse-poor hASCs. These cells also released higher amounts of certain growth factors, particularly under hypoxic conditions, compared with Muse-poor cells. Skin ulcers were generated in severe combined immunodeficiency (SCID) mice with type 1 diabetes, which showed delayed wound healing compared with nondiabetic SCID mice. Treatment with Muse-rich cells significantly accelerated wound healing compared with treatment with Muse-poor cells. Transplanted cells were integrated into the regenerated dermis as vascular endothelial cells and other cells. However, they were not detected in the surrounding intact regions. Thus, the selected population of ASCs has greater therapeutic effects to accelerate impaired wound healing associated with type 1 diabetes. These cells can be achieved in large amounts with minimal morbidity and could be a practical tool for a variety of stem cell-depleted or ischemic conditions of various organs and tissues.

Application of normobaric hyperoxygenation to an ischemic flap and a composite skin graft.

BACKGROUND: Hyperbaric oxygenation has been used for various purposes, but its clinical application is limited due to its pulmonary toxicity. We evaluated the therapeutic value of normobaric hyperoxygenation (NBO) for vascularized and nonvascularized tissue transplantation. METHODS: Tissue oxygen partial pressure (PtO2) was measured for various organs in mice under inspiratory oxygen of 20%, 60%, or 100%. A rectangular skin flap (1 × 4 cm) or a composite skin graft (2 × 2 cm) was made on the back of mice, which were housed under 20% or 60% oxygen for the first 3 days after surgery. Cell survival was also examined in organ culture skin samples. RESULTS: PtO2 varied among tissues/organs, but increased depending on inspiratory oxygen concentration in all tissues/organs. Although NBO with 100% O2 was toxic, NBO with 60% O2 was safe even when used continuously for a long period. NBO did not significantly improve survival of the rectangular skin flap. On the other hand, in the composite skin graft model, the engraftment area increased significantly (52 ± 10 at 20% vs 68 ± 5.1 at 60%) and contraction decreased significantly (42 ± 8.0 at 20% vs 27 ± 5.7 at 60%). Organ culture of a composite skin sample showed significant cell death under lower oxygen concentrations, supporting the data in vivo. CONCLUSIONS: The composite graft was maintained until revascularization by plasmatic diffusion from surrounding tissues, in which PtO2 was improved by NBO. NBO may be an effective adjunct therapy that can be performed readily after nonvascularized tissue grafting.

Normobaric hyperoxygenation enhances initial survival, regeneration, and final retention in fat grafting.

BACKGROUND: Fat grafting is a promising modality for soft-tissue augmentation/reconstruction. However, grafted fat tissue is not initially perfused and relies on plasmatic diffusion from the recipient bed until revascularization occurs. The authors evaluated the therapeutic effects of normobaric hyperoxygenation for enhancing fat graft retention. METHODS: Aspirated human fat tissue was cultured under tissue hypoxia (1% oxygen), normoxia (6%), and hyperoxia (20%) levels, and evaluated for adipocyte viability. Inguinal fat pads were autografted under mouse scalps (n=36), and mice were housed in either 20% (control) or 60% (normobaric hyperoxygenation) atmospheric oxygen for the first 3 days, and then returned to normoxia. Samples harvested at 0, 1, 2, 4, 8, and 12 weeks were analyzed immunohistochemically for adipocyte viability and regeneration. RESULTS: Organ culture adipocytes died more quickly under lower oxygen tensions; thus, hyperoxygenation of recipient tissues may delay adipocyte death after fat grafting. Autografted mouse adipose tissue underwent dynamic remodeling, from ischemic degeneration to partial regeneration, over 12 weeks. Normobaric hyperoxygenation grafted samples showed significantly larger survival zones and engraftment scores (calculated using sample weight and adipocyte viability) at 1 and 12 weeks, respectively, than control samples. In addition, adipocyte regeneration (number of perilipin-positive preadipocytes), which peaked at 4 weeks, was significantly increased in normobaric hyperoxygenation samples. CONCLUSION: The normobaric hyperoxygenation protocol using 60% oxygen can be safely applied to enhance adipocyte survival, regeneration, and final engraftment after fat grafting.