Preoperative estimation of vertical profunda artery perforator flap weight using computed tomography angiography for breast reconstruction.

BACKGROUND: The vertical profunda artery perforator (v-PAP) flap is limited in terms of the tissue volume that can be harvested but is a suitable graft for Japanese patients with relatively small breast sizes. The objectives of this study were to identify the parameter most closely correlated with v-PAP flap weight on computed tomography angiography (CTA) images and to create an easy-to-use v-PAP flap weight estimation formula by linear regression analysis using the identified parameter. PATIENTS AND METHODS: Thirty v-PAP flaps in 25 patients who underwent breast reconstruction were retrospectively analyzed. Mean age was 46.1 (range: 32-73) years, and mean BMI was 20.0 (range: 15.3-23.6) kg/m2 . On a CT horizontal section of the thigh taken at level of the center of the long axis of the flap, the following parameters were measured from the anterior margin of the gracilis muscle to the posterior margin of the semimembranosus muscle using image processing software: fat area, fat thickness, thigh circumference, and skin paddle area. Linear regression analysis was then performed with the weight of the harvested v-PAP flap as the objective variable and the above parameters as explanatory variables to predict skin flap weight. RESULTS: Correlations with v-PAP flap weight of each parameter were as follows: r = 0.66 (p < .0001) for fat thickness, r = 0.32 (p = .081) for total thigh area, r = 0.36 (p = .054) for thigh circumference, r = 0.27 (p = .153) for skin paddle area, and r = 0.84 (p < .0001) for fat area. Thus, the fat area had the strongest correlation with v-PAP flap weight. The v-PAP flap weight estimation formula obtained by linear regression analysis including fat area was as follows: 7.3 × fat area + 114 (coefficient of determination: R2  = 0.70, p < .0001, RMSE = 24). The engraftment rate of the 30 v-PAP flaps was 100%. One patient developed postoperative venous thrombosis at the vascular anastomosis site, but underwent successful microsurgical revision, leading to flap salvage. During the >6-month follow-up period, there were no notable complications in the reconstructed breasts and donor sites. CONCLUSIONS: The v-PAP flap weight estimation formula we developed in this study showed a high correlation with measured values, allowing for easy estimation using only a single CTA horizontal section of the thigh.

Prevention of denervated muscle atrophy with accelerated nerve-regeneration by babysitter procedure in rat facial nerve paralysis model.

PURPOSE: The "babysitter" procedure is a reconstruction technique for facial nerve complete paralysis and uses the movement source from the healthy facial nerve with a cross-nerve graft. First, an end-to-side neurorrhaphy is performed between the affected facial nerve trunk and hypoglossal nerve for continuously delivering stimuli to the mimetic muscles for preventing the atrophy of mimetic muscles. Despite favorable clinical results, histological and physiological mechanisms remain unknown. This study attempted to establish a model for the "babysitter" procedure and find its efficacy in rats with facial nerve complete paralysis. MATERIALS AND METHODS: A total of 16 Lewis rats were used and divided into 2 groups; cross nerve graft (n = 8) and babysitter groups (n = 8). The facial nerve trunk was transected in both groups. Babysitter group underwent a two-stage procedure. Cross nerve graft group underwent only the transfer of nerve graft from the healthy side to affected side. The animals were assessed physiologically by compound muscle action potential (CMAP), and the regenerated nerve tissues were evaluated histopathologically at 13 weeks after surgery. RESULTS: Facial nucleus stained with retrograde tracers proved the re-innervation of affected facial muscle by the babysitter procedure. In CMAP, the amplitude of babysitter group was significantly higher than that of the cross-facial nerve graft group (p < .05). Histological examination found a significant difference in myelin g-ratio between two groups (p < .05). CONCLUSION: This study investigated the "babysitter" procedure for rat facial nerve palsy. Babysitter procedure shortened the denervation period without mimic muscle atrophy.

Lacrimal Duct Obstruction Caused by Nasomaxillary Fracture: A Retrospective Analysis of Consecutive 12 Patients by Computed Tomographic Dacryocystography.

ABSTRACT: Nasomaxillary fracture is a characteristic mid-facial fracture, and there are no reports showing the fracture damaging the nasolacrimal system (NLS). This report described nasomaxillary fracture cases with NLS damages, which were assessed by computed tomographic dacryocystography (CT-DCG). A retrospective cohort study of nasomaxillary fractures diagnosed by CT was conducted from 2007 to 2015. Twelve patients (mean age: 27.5 years) were found, and their clinical symptoms were as follows: nasal deformity in 10 patients, infra-orbital hypoesthesia in 7, epiphora in 5, and diplopia in one. CT-DCG was performed for 2 patients who complained epiphora, and obstruction was found in 1 patient. All patients underwent open reduction and internal fixation (ORIF), and epiphora in 5 patients was improved. One patient, however, complained epiphora postoperatively, which was supposed to be due to the unsuitable screw insertion. Since nasomaxillary fracture could give NLS obstruction, CT-DCG is useful for diagnosis. Although ORIF is an optimal treatment, attention is needed to avoid the lacrimal canal in screwing on the nasomaxillary buttress.

Blood carboxyhemoglobin elimination curve, half-lifetime, and arterial-venous differences in acute phase of carbon monoxide poisoning in ovine smoke inhalation injury model.

Smoke inhalation injury (SII) affects more than 50,000 people annually causing carbon monoxide (CO) poisoning. Although the increased blood level of carboxyhemoglobin (CO-Hb) is frequently used to confirm the diagnosis of SII, knowledge of its elimination in the acute phase is still limited. The aim of this study is to determine CO-Hb elimination rates and their differences in arterial (aCO-Hb) and mixed-venous (vCO-Hb) blood following severe SII in a clinically relevant ovine model. Forty-three chronically instrumented female sheep were subjected to SII (12 breaths, 4 sets) through tracheostomy tube under anesthesia and analgesia. After the SII, sheep were awakened and placed on a mechanical ventilator (FiO2 = 1.0, tidal volume 12 mL/kg, and PEEP = 5cmH2O) and monitored. Arterial and mixed-venous blood samples were withdrawn simultaneously for blood gas analysis at various time points to determine CO-HB half-lifetime and an elimination curve. The mean of highest aCO-Hb level during SII was 70.8 ± 13.9%. The aCO-Hb elimination curve showed an approximated exponential decay during the first 60 min. Per mixed linear regression model analysis, aCO-Hb significantly (p < 0.001) declined (4.3%/minute) with a decay constant lambda of 0.044. With this lambda, mean lifetime and half-lifetime of aCO-Hb were 22.7 and 15.7 min, respectively. The aCO-Hb was significantly lower compared to vCO-Hb at all-time points (0-180 min). To our knowledge, this is the first report describing CO-Hb elimination curve in the acute phase after severe SII in the clinically relevant ovine model. Our data shows that CO-Hb is decreasing in linear manner with supportive mechanical ventilation (0-60 min). The results may help to understand CO-Hb elimination curve in the acute phase and improvement of pre-hospital and initial clinical care in patients with CO poisoning.

Surgical anatomy of ovine facial and hypoglossal nerves for facial nerve reconstruction and regeneration research: An experimental study in sheep.

BACKGROUND: The lack of a clinically relevant animal model for facial nerve research is a challenge. The goal of this study was to investigate the anatomy of the ovine facial and hypoglossal nerves to establish a clinically relevant facial nerve research model. MATERIALS AND METHODS: Six cadaver female Merino sheep (33.5 ± 3 kg, approximately 3 years old) and three anesthetized female Merino sheep (30 ± 3 kg, approximately 3 years old) were used. In cadaver sheep, a right side preauricular to submandibular incision was made. Dimensions of the face, neck, and length of facial nerve were measured. In anesthetized sheep, each facial nerve branch and hypoglossal nerve in the right side was stimulated. The number of myelinated fibers was analyzed histologically. RESULTS: The facial nerve exited the stylomastoid foramen and divided into upper and lower branches. The lower branch then subdivided into buccal and marginal mandibular branches. The hypoglossal nerve was observed behind the digastric posterior belly. Stimulation revealed the temporal, zygomatic, buccal, marginal mandibular, and cervical branch innervated the forehead, orbicularis, upper lip and nasal, lower lip, and platysma, respectively. The number of myelinated fibers of the main trunk, upper, buccal, lower branch, and hypoglossal nerve was 11 350 ± 1851, 4766 ± 1000, 5107 ± 218, 3159 ± 450, and 7604 ± 636, respectively. The length of the main trunk was 9.2 ± 1.5 mm, and distance of the marginal mandibular branch to the facial artery was 94 ± 6.8 mm. CONCLUSIONS: Due to the similarity in nerve anatomy and innervation, the ovine model can be used as a clinically relevant and suitable model for facial nerve research.

A collagen-coated PGA conduit for interpositional-jump graft with end-to-side neurorrhaphy for treating facial nerve paralysis in rat.

PURPOSE: This study investigated the potential of collagen-coated polyglycolic acid (PGA) tube with interpositional jump graft (IPJG) in rat. MATERIALS AND METHODS: A total of 16 Lewis rats were used in this study. Facial nerve paralysis was created by ligating facial nerve trunk with a ligature clip. The rats were divided into 3 groups. Nerve conduit group (n = 6) were treated by IPJG with collagen-coated PGA tubes between the facial nerve trunks and the hypoglossal nerves. Autograft group (n = 6) were treated by IPJG with the greater auricular nerves. As the control group (n = 4), non-treated-model rats with facial nerve paralysis were used. The number of myelinated fibers, fiber diameter, axon diameter, myelin thickness, and g-ratio, were analyzed histologically at 13 weeks after surgery. Compound muscle action potential (CMAP) and retrograde tracing were measured. RESULT: Although the number of myelinated fibers in autograft group (1957 ± 775) had significantly higher than that of nerve conduit group (90 ± 41, P < .05), the nerve conduit group showed the regeneration of myelinated nerve axons. CMAP amplitude values of the autograft (4706 ± 1154 µV) and the nerve conduit groups (4119 ± 1397 µV) were significantly higher than that of the control group (915 ± 789 µV, P < .05). Retrograde tracing confirmed the double innervation of mimetic muscles by the facial and hypoglossal nucleus in both groups. CONCLUSION: This study showed histologically and physiologically the superior effectiveness of performing IPJG with a collagen-coated PGA conduit in a rat model.

Adipose-derived stem cells and the stromal vascular fraction in polyglycolic acid-collagen nerve conduits promote rat facial nerve regeneration.

Adipose-derived stem cells (ADSCs) and the stromal vascular fraction (SVF) promote nerve regeneration. Biodegradable nerve conduits are used to treat peripheral nerve injuries, but their efficiencies are lower than those of autologous nerve grafts. This study developed biodegradable nerve conduits containing ADSCs and SVF and evaluated their facial nerve regenerating abilities in a rat model with a 7-mm nerve defect. SVF and ADSCs were individually poured into nerve conduits with polyglycolic acid-type I collagen as a scaffold (ADSCs and SVF groups). The conduits were grafted on to the nerve defects. As the control, the defect was bridged with polyglycolic acid-collagen nerve conduits without cells. At 13 weeks, after transplantation, the regenerated nerves were evaluated physiologically and histologically. The compound muscle action potential of the SVF group was significantly higher in amplitude than that of the control group. Electron microscopy showed that the axon diameter of the SVF group was the largest, followed by the ADSC group and control group with significant differences among them. The SVF group had the largest fiber diameter, followed by the ADSC group and control group with significant differences among them. The ADSC group had the highest myelin thickness, followed by the SVF group and control group with significant differences among them. Identical excellent promoting effects on nerve regeneration were observed in both the ADSC and SVF groups. Using SVF in conduits was more practical than using ADSCs because only the enzymatic process was required to prepare SVF, indicating that SVF could be more suitable to induce nerve regeneration.

Axonal supercharged interpositional jump-graft with a hybrid artificial nerve conduit containing adipose-derived stem cells in facial nerve paresis rat model.

PURPOSE: Interpositional jump-graft (IPJG) technique with the hypoglossal nerve for supercharging can be applied in a facial nerve paresis case. In IPJG, an autologous nerve is required, and the donor site morbidity is unavoidable. Biodegradable nerve conduits are made from polyglycolic acid (PGA) and used recently without donor site complications after providing autologous grafts. Hybrid artificial nerve conduits with adipose-derived stem cells (ASCs) also attract attention as a nerve-regeneration enhancing agent. This study examined the effect of hybrid artificial nerve conduit on IPJG. MATERIALS AND METHODS: A total of 34 Lewis rats were used and divided into 4 groups by the bridge materials: autograft (n = 8), PGA nerve conduit (n = 8), hybrid PGA nerve conduit with ASCs (n = 8), and the nontreated control groups (n = 8). ASCs were collected from 2 rats and cultured. The animals were assessed physiologically and histopathologically at 13 weeks after surgery. RESULTS: In compound muscle action potential, the amplitude of hybrid PGA group (3,222 ± 1,779 µV) was significantly higher than that of PGA group (1,961 ± 445 µV, P < .05), and no significant difference between hybrid PGA and autograft group. All treated groups showed a myelinated nerve regeneration with double innervation in hypoglossal and facial nerve nuclei for vibrissal muscle. CONCLUSION: This study showed the effectiveness of IPJG with a hybrid PGA conduit especially in physiological examination.

Combined treatment with vitamin C, hydrocortisone and thiamine does not attenuate morbidity and mortality of septic sheep.

BACKGROUND: Sepsis is associated with a highest mortality rate in the ICU. Present study tests the efficacy of combined therapy with vitamin C, hydrocortisone and thiamine (combined therapy) in the ovine model of sepsis induced by Pseudomonas aeruginosa. In this study, sepsis was induced in sheep by instillation of Pseudomonas aeruginosa (1 × 1011 CFU) into the lungs via bronchoscope, under anesthesia. Nine hours after injury, intravenous infusion of vitamin C (0.75 g every 6 h), hydrocortisone (25 mg every 6 h), and thiamine (100 mg every 12 h) or saline was given to the treatment and control groups. Cardiopulmonary variables were recorded. RESULTS: The survival rate was 16.7% in control and 33.3% in treatment groups. In the control group, mean arterial pressure dropped from 93.6 ± 8.6 to 75.5 ± 9.7 mmHg by 9 h, which was not affected by the combined therapy. Pulmonary dysfunction was not attenuated by the combined therapy either. The combined therapy had no effect on increased extravascular lung water content and fluid effusion into thoracic cavity. The bacterial number in the bronchoalveolar lavage fluid was significantly increased in the treatment group than the control group. The blood bacterial number remained comparable between groups. CONCLUSIONS: Combined vitamin C, hydrocortisone, and thiamine did not attenuate severity of ovine sepsis.

Dorsal Hand Reconstruction with Web Contracture Release Using Free Superficial Inferior Epigastric Artery Flap.

We present a case in which reconstruction of the dorsum of the hand and finger web space was carried out concurrently with the insertion of a superficial inferior epigastric artery flap into the interdigital spaces. This approach was taken to prevent the potential development of subsequent web space contracture. The patient, a 57-year-old woman, presented with a necrotizing soft tissue infection on the dorsum of her left hand, resulting in a full-thickness skin defect extending from the metacarpophalangeal joint to the wrist, with exposure of the extensor tendons. The reconstructive surgery involved raising a superficial inferior epigastric artery flap and transplanting it onto the tissue defect, to cover not only the dorsal defect but also the interdigital spaces after releasing web space contracture. Consequently, the surgery successfully released scar contractures on the dorsum of the hand and provided adequate interdigital space formation without requiring additional procedures, except defatting. At the 7-month postoperative follow-up, the patient had a good outcome with shoulder and hand (Quick Disabilities of Arm, Shoulder and Hand) score of 28.9 points. Interdigital scar contractures often lead to decreased fine motor skills and functional impairment, affect aesthetics, and require a prolonged period for social reintegration. This surgical technique involves simultaneous one-stage closure of the dorsal defect with a flap and interdigital reconstruction to prevent future scar contractures and functional impairments, and is a valuable approach for shortening the treatment duration.

Minimal Scar Autologous Breast Reconstruction with Skin-sparing Mastectomy.

A skin paddle severely impairs the appearance of the reconstructed breast. We have established a new technique called "minimal scar autologous breast reconstruction" involving delayed nipple reconstruction using a local flap designed on the skin paddle and simultaneous resection of the residual skin paddle. Methods: We analyzed 20 patients with unilateral breast cancer who underwent skin-sparing mastectomy followed by immediate breast reconstruction using a free flap (deep inferior epigastric perforator flap in 13 patients and profunda artery perforator flap in seven). Approximately 1 year after primary reconstruction, nipple reconstruction using an arrow flap designed on the skin paddle and resection of the residual skin paddle were performed. Several months later, medical areola tattooing was performed. Bilateral breast symmetry scores, obtained from the distances between anatomic landmarks, were compared before and after breast reconstruction. Results: Postoperative complications such as necrosis of the reconstructed nipple were not observed after two-stage reconstruction, and all procedures including total resection of the skin paddle, nipple reconstruction, and medical tattooing were performed successfully in all cases. Aesthetic outcomes were excellent: comparison of symmetry scores showed no significant differences in any parameters between before surgery and after reconstruction of the nipple-areola complex. Conclusions: We have established step-by-step strategies for mastectomy, autologous breast reconstruction, and then nipple reconstruction, keeping in mind that the skin paddle would later be totally resected in nipple reconstruction, and thereby achieved breast reconstruction with markedly reduced postoperative scarring compared with conventional autologous breast reconstruction.

Estimation of Mastectomy Volume Using Preoperative Mastectomy Simulation Images Acquired by the Vectra H2 System.

Preoperative prediction of breast volume is very important in planning breast reconstruction. In this study, we assessed the usefulness of a novel method for preoperative estimation of mastectomy volume by comparing the weight of actual mastectomy specimens with the values predicted by the developed method using the Vectra H2. Methods: All patients underwent skin-sparing mastectomy and immediate autologous breast reconstruction. Preoperatively, the patient's breast was scanned using the Vectra H2 and a postmastectomy simulation image was constructed on a personal computer. The estimated mastectomy volume was calculated by comparing the preoperative and postmastectomy three-dimensional simulation images. Correlation coefficients with the estimated mastectomy volume were calculated for the actual mastectomy weight and the transplanted flap weight. Results: Forty-five breasts of 42 patients were prospectively analyzed. The correlations with the estimated mastectomy volume were r = 0.95 (P < 0.0001) for actual mastectomy weight and r = 0.84 (P < 0.0001) for transplanted free-flap weight. The mastectomy weight estimation formula obtained by linear regression analysis using the estimated mastectomy volume was 0.98 × estimated mastectomy volume + 5.4 (coefficient of determination R2 = 0.90, P < 0.0001). The root-mean-square error for the mastectomy weight estimation formula was 38 g. Conclusions: We used the Vectra H2 system to predict mastectomy volume. The predictions provided by this method were highly accurate. Three-dimensional imaging is a noncontact, noninvasive measurement method that is both accurate and simple to perform. Use of this effective tool for volume prediction is expected to increase in the future.

Surgical Treatment of Ischial Ulcers Associated with Deposition of ß2-Microglobulin in Two Cases of Dialysis-related Amyloidosis.

The accumulation of ß2-microglobulin due to long-term hemodialysis is known as dialysis-related amyloidosis, a rare phenomenon that manifests as a subcutaneous mass. Subcutaneous ß2-microglobulin amyloidomas are predominantly located on the buttocks. Owing to the load-bearing properties of this location and proximity to the anus, amyloidomas on the buttocks may be prone to pressure ulcers and infection. This report presents two cases of long-term hemodialysis patients who required surgical treatment for infected ulcers caused by buttock amyloidomas. In the first case, treatment failed after the amyloidoma was excised and covered with a single-stage skin flap. In the second case, successful treatment was accomplished by reducing the volume of the amyloidoma, followed by a pause to allow for granulation growth and a two-stage skin graft. Amyloids of this nature are known to be cytotoxic; thus, a robust wound preparation technique should be used until the excision site is fully covered with granulation tissue before wound closure is initiated at the time of surgery. In addition, buttock amyloidomas often extend subcutaneously through the hip joint, and repeated infections may lead to more severe outcomes, such as hip joint infections. The number of dialysis-related amyloidosis patients has been increasing in recent years; thus, we report these case studies to improve patient outcomes in similar cases.

Effects of nebulized adipose-derived mesenchymal stem cells on acute lung injury following smoke inhalation in sheep.

INTRODUCTION: Treatment of ARDS caused by smoke inhalation is challenging with no specific therapies available. The aim of this study was to test the efficacy of nebulized adipose-derived mesenchymal stem cells (ASCs) in a well-characterized, clinically relevant ovine model of smoke inhalation injury. MATERIAL AND METHODS: Fourteen female Merino sheep were surgically instrumented 5-7 days prior to study. After induction of acute lung injury (ALI) by cooled cotton smoke insufflation into the lungs (under anesthesia and analgesia), sheep were placed on a mechanical ventilator for 48 hrs and monitored for cardiopulmonary hemodynamics in a conscious state. ASCs were isolated from ovine adipose tissue. Sheep were randomly allocated to two groups after smoke injury: 1) ASCs group (n = 6): 10 million ASCs were nebulized into the airway at 1 hr post-injury; and 2) Control group (n = 8): Nebulized with saline into the airways at 1 hr post-injury. ASCs were labeled with green fluorescent protein (GFP) to trace cells within the lung. ASCs viability was determined in bronchoalveolar lavage fluid (BALF). RESULTS: PaO2/FiO2 in the ASCs group was significantly higher than in the control group (p = 0.001) at 24 hrs. Oxygenation index: (mean airway pressure × FiO2/PaO2) was significantly lower in the ASCs group at 36 hr (p = 0.003). Pulmonary shunt fraction tended to be lower in the ASCs group as compared to the control group. GFP-labelled ASCs were found on the surface of trachea epithelium 48 hrs after injury. The viability of ASCs in BALF was significantly lower than those exposed to the control vehicle solution. CONCLUSION: Nebulized ASCs moderately improved pulmonary function and delayed the onset of ARDS.

GENDER-RELATED VARIATIONS IN PATHOPHYSIOLOGICAL RESPONSES TO METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS PNEUMONIA AND SEPSIS.

ABSTRACT: In preclinical studies, the protective effects of female sex hormones and the immunosuppressive effects of male sex hormones were demonstrated. However, gender-related differences in multiorgan failure and mortality in clinical trials have not been consistently explained. This study aims to investigate gender-related differences in the development and progression of sepsis using a clinically relevant ovine model of sepsis. Adult Merino male (n=7) and female (n=7) sheep were surgically prepared with multiple catheters before the study. To induce sepsis, bronchoscopy instilled methicillin-resistant Staphylococcus aureus into sheep's lungs. The time from the bacterial inoculation until the modified Quick Sequential Organ Failure Assessment (q-SOFA) score became positive was measured and analyzed primarily. We also compared the SOFA score between these male and female sheep over time. Survival, hemodynamic changes, the severity of pulmonary dysfunction, and microvascular hyperpermeability were also compared. The time from the onset of bacterial inoculation to the positive q-SOFA in male sheep was significantly shorter than in female sheep. Mortality was not different between these sheep (14% vs. 14%). There were no significant differences in hemodynamic changes and pulmonary function between the two groups at any time point. Similar changes in hematocrit, urine output, and fluid balance were observed between females and males. The present data indicate that the onset of multiple organ failure and progression of sepsis is faster in male sheep than in female sheep, even though the severity of cardiopulmonary function is comparable over time. Further studies are warranted to validate the above results.

Dose and gender dependence of chlorine inhalation in a conscious ovine model.

Characterization of the pathophysiology of ARDS following chlorine gas inhalation in clinically relevant translational large animal models is essential, as the opportunity for clinical trials in this type of trauma is extremely limited. To investigate Cl2 concentration and gender-dependent ARDS severity. Sheep (n = 54) were exposed to air or Cl2 premixed in air at a concentration of 50, 100, 200, and 300 ppm for 30 min under anesthesia/analgesia and monitored for an additional 48 h in a conscious state. Cardiopulmonary variables and survival endpoints were compared between male and female sheep. Overall there were no significant differences in the responses of female and male sheep except pulmonary oxygenation tended to be better in the male sheep (300 ppm group), and the pulmonary arterial pressure was lower (200 ppm group). The onset of mild ARDS (200 < PaO2/FiO2 ≤ 300) was observed at 36 h post exposure in the 50 ppm group, whereas the 100 ppm group developed mild and moderate (100 ≤ PaO2/FiO2 ≤ 200) ARDS by 12 and 36 h after injury, respectively. The 200 ppm and 300 ppm groups developed moderate ARDS within 6 and 3 h after injury, respectively. The 300 ppm group progressed to severe (PaO2/FiO2 ≤ 100) ARDS at 18 h after injury. Increases in pPeak and pPlateau were noted in all injured animals. Compared to sham, inhalation of 200 ppm and 300 ppm Cl2 significantly increased lung extravascular water content. The thoracic cavity fluid accumulation dose-dependently increased with the severity of trauma as compared to sham. At necropsy, the lungs were red, heavy, solidified, and fluid filled; the injury severity grew with increasing Cl2 concentration. The severity of ARDS and mortality rate directly correlated to inhaled Cl2 concentrations. No significant sex-dependent differences were found in measured endpoint variables.

Basic fibroblast growth factor-impregnated collagen gelatin sponge completes formation of dermis-like tissue within 2 weeks: A prospective cohort study.

Introduction: This study included patients who underwent full-thickness skin reconstruction using a two-stage procedure comprising basic fibroblast growth factor-impregnated collagen gelatin sponge (bFGF-CGS) implantation and autologous skin grafting, and the take rate of skin grafts was compared between groups of patients who underwent autologous skin grafting after a waiting period of <2 weeks or ≥2 weeks. Methods: An acute, full-thickness skin defect was treated with thorough debridement of contaminated/necrotic tissue, followed by washing with saline and hemostasis with electrocautery. Then, an FGF-CGS was fixed to the skin defect wound using non-absorbable sutures, and after confirming regeneration of sufficient dermis-like tissue, the second-stage autologous skin grafting was performed for wound closure. Patients were divided into two groups according to the waiting period before the second operation, namely, <2 weeks (early group) and ≥2 weeks (late group), and the take rate of skin grafts was compared. Results: We enrolled and treated 25 cases (18 men, 7 women; mean age: 49 [range 2-86] years). The mean take rate of skin grafts was 93% (range 80%-100%) in the early group and 92% (range 65%-100%) in the late group, with no significant difference between the two groups. There was a significant difference between the groups in mean time to complete healing: 25.2 ± 9.7 days in the early group vs 44.7 ± 27 days in the late group (p < 0.05). Conclusion: Our data suggest that bFGF-CGF can form dermis-like granulation tissue with sufficient quality as a graft bed for skin transplantation within 2 weeks.

Sensate Reverse Medial Plantar Flap for Reliable Forefoot Reconstruction with Flow-through Anterolateral Thigh Flap.

A reverse medial plantar flap is a major option for reconstructing the plantar forefoot. However, reconstruction of the distal forefoot stretches the vessels, causing tightness, and the skin graft to the donor site adds pressure to the vessel, precipitating venous congestion. We used a reverse medial plantar flap to reconstruct the lateral distal forefoot with a flow-through of the anterolateral thigh (ALT) flap for donor site coverage to maintain physiological and stable blood flow. A 74-year-old woman presented to our hospital with a 20-year history of left forefoot skin tumor. The tumor was resected, and histological examination revealed porocarcinoma in the cystic poroid hidradenoma. Additional excision was performed, and the defect area was covered with a biodegradable artificial dermis. The skin defect of the lateral distal plantar area was reconstructed with a reverse medial plantar flap with a reverse flow Y-V pedicle extension method, and the donor site was reconstructed with an ALT flap interposing the lateral circumflex femoral artery with the transected posterior tibial artery. The flap was completely engrafted without any complications, including arterial ischemia or venous congestion, during or after surgery. A distally based reverse medial plantar flap with a reverse flow Y-V pedicle extension method and flow-through of the ALT flap should be considered for the reconstruction of the lateral distal forefoot with a large defect. This method can maximize flap extension and maintain stable arterial inflow and venous drainage without the major complications of venous congestion.

Fibroblast Growth Factor-Impregnated Collagen-Gelatin Sponge Improves Keratinocyte Sheet Survival.

Commercially available cultured epithelial keratinocyte sheets (KSs) have played an essential role in wound healing over the past four decades. Despite the initial uptake by the dermal elements, the survival rate of KS on the dermis-like tissue generated by conventional artificial dermis (AD) is low, making this method unsuitable for standard treatments. Therefore, an innovative AD such as collagen-gelatin sponge (CGS) that maintains the release of human recombinant basic fibroblast growth factor (bFGF) may promote wound healing. In this study, we examined whether combination therapy with KSs and CGS with bFGF (bFGF-CGS) could enhance KS survival by heterologous grafting by transplantation of human-derived KSs in an athymic nude rat wound model of staged skin reconstruction. The CGSs were implanted into skin defect wounds on athymic nude rats, which were then divided into two experimental groups: the bFGF group (CGSs containing bFGF, n = 8) and the control group (CGSs with saline, n = 8). Two weeks after implantation, human epithelial cell-derived KSs were grafted onto the dermis-like tissue, followed by assessment of the survival and morphology at 1 week later using digital imaging, histology (hematoxylin and eosin and Masson's trichrome staining), immunohistology (von Willebrand factor), immunohistochemistry (cytokeratin 1-5-6, Ki-67), and immunofluorescence (collagen IV, pan-cytokeratins) analyses. The bFGF group showed a significantly higher KS survival area (86 ± 58 mm2 vs. 32 ± 22 mm2; p < 0.05) and increased epidermal thickness (158 ± 66 µm vs. 86 ± 40 µm; p < 0.05) compared with the control group, along with higher dermis-like tissue regeneration, neovascularization, epidermal maturation, and basement membrane development. These results indicate that the survival rate of KSs in the dermis-like tissue formed by bFGF-CGS was significantly increased. Therefore, combination treatment of bFGF-CGS and KSs shows potential for full-thickness skin defect reconstruction in clinical situations. Impact statement This study highlights how using a combination of cultures, keratinocyte sheets, and collagen-gelatin sponge containing basic fibroblast growth factors can significantly improve cell survival in athymic nude rats with staged skin reconstruction. Our study makes a significant contribution to the literature because it highlights a novel and improved strategy for treating a very common condition such as skin wounds arising from many conditions. Clinical translation of this study may be useful for treating skin wounds.

Ovine model of burn wounds grafted with ovine cadaver skin.

Shortage in autograft to cover burn wounds involves a frequent use of cadaver skin (CS) as a temporary cover to prevent infection, dehydration and preparation of wounds for subsequent autografting. We aimed to establish an ovine model of burn wound healing using ovine CS (OCS). Quality and efficacy of fresh and frozen OCS overlaid on to excised 3rd degree flame burn wounds in sheep were evaluated in comparison to autograft. Histologically, autografted wounds maintained normal skin structure at different time points. Wounds overlaid with fresh OCS graft showed signs of rejection starting from day 7. At day 14, the epidermis was mostly rejected. The rejection was completed by day 20 with signs of immunoreaction and presence of many immune cells. Frozen OCS was rejected in the same pattern. Immediately prior to grafting, the thickness was comparable between freshly prepared and frozen OCS for 10 or 40 days. Significant reduction in viability was detected in OCS frozen for 40 days. Both fresh or frozen ovine OCS were rejected within 10 days that mimics CS rejection time in humans (∼8.4 days), suggesting that ovine model of burn wound grafted with OCS can successfully be used in burn wound research mimicking clinical scenario.