Scarring At Donor Sites After Split-Thickness Skin Graft: A Prospective, Longitudinal, Randomized Trial.

OBJECTIVE: The aim of this study was to evaluate scarring at split-thickness skin graft donor sites 8 years after surgery. METHODS: At surgery, 67 patients were randomized to hydrofiber, polyurethane foam, or porcine xenograft treatment. Scars were evaluated with the Patient and Observer Scar Assessment Scale. RESULTS: Results showed significant differences in observed scar outcomes at donor sites, leaving the polyurethane foam-treated and the porcine xenograft-treated patients with the least satisfying scars. Multivariable regression analysis showed that the group treated with the xenografts had worse scores for overall opinion of the scar than did the other groups (P = .03), the most important factor being pigmentation. There was no correlation between duration of healing time and quality of the scar. CONCLUSIONS: There were significant differences among the groups, with the hydrofiber group being the most satisfied with the appearance of their scar.

Hyperaemic changes in forearm skin perfusion and RBC concentration after increasing occlusion times.

Tissue occlusion and the hyperaemic response upon reperfusion can be used as a tool to assess microvascular function in various vascular diseases. Currently, laser Doppler flowmetry (LDF) is applied most often to measure hyperaemic responses. In this study, we have applied tissue viability imaging (TiVi) and LDF to measure the change in red blood cell concentration and perfusion in the skin after occlusions of the forearm with increasing duration. We have found that there is a strong correlation between the changes in perfusion and red blood cell (RBC) concentration during post-occlusive hyperaemia (perfusion: r=0.80; RBC concentration: r=0.94). This correlation increases with longer occlusion durations (1, 5 and 10min). Furthermore, for both perfusion and RBC concentration, the maximum responses (perfusion: r(2)=0.59; RBC concentration: r(2)=0.78) and the recovery times (perfusion: r(2)=0.62; RBC concentration: r(2)=0.91) increase linearly with the duration of the occlusion. Maximum responses and recovery times were more reproducible for RBC concentration (as measured with TiVi) than for perfusion (as measured with LDF). These results show that perfusion and RBC concentration are related during post-occlusive hyperaemia and that TiVi can be used as a tool in the assessment of hyperaemic responses that has advantages in terms of reproducibility, sensitivity and ease of use.

Tissue engineering of flexor tendons: the effect of a tissue bioreactor on adipoderived stem cell-seeded and fibroblast-seeded tendon constructs.

PURPOSE: Tissue-engineered flexor tendons could eventually be used for reconstruction of large tendon defects. The goal of this project was to examine the effect of a tissue bioreactor on the biomechanical properties of tendon constructs seeded with adipoderived stem cells (ASCs) and fibroblasts (Fs). METHODS: Rabbit rear paw flexor tendons were acellularized and seeded with ASCs or Fs. A custom bioreactor applied a cyclic mechanical load of 1.25 N at 1 cycle/minute for 5 days onto the tendon constructs. Three additional groups were used as controls: fresh tendons and tendons reseeded with either ASCs or Fs that were not exposed to the bioreactor treatment and were left in stationary incubation for 5 days. We compared the ultimate tensile stress (UTS) and elastic modulus (EM) of bioreactor-treated tendons with the unloaded control tendons and fresh tendons. Comparison across groups was assessed using one-way analysis of variance with the significance level set at p<.05. Pairwise comparison between the samples was determined by using the Tukey test. RESULTS: The UTS and EM values of bioreactor-treated tendons that were exposed to cyclic load were significantly higher than those of unloaded control tendons. Acellularized tendon constructs that were reseeded with ASCs and exposed to a cyclic load had a UTS of 66.76 MPa and an EM of 906.68 MPa; their unloaded equivalents had a UTS of 47.90 MPa and an EM of 715.57 MPa. Similar trends were found in the fibroblast-seeded tendon constructs that were exposed to the bioreactor treatment. The bioreactor-treated tendons approached the UTS and EM values of fresh tendons. Histologically, we found that cells reoriented themselves parallel to the direction of strain in response to cyclic strain. CONCLUSIONS: The application of cyclic strain on seeded tendon constructs that were treated with the bioreactor helped achieve a UTS and an EM comparable with those of fresh tendons. Bioreactor pretreatment and alternative cell lines, such as ASCs and Fs, might therefore contribute to the in vitro production of strong tendon material.

Spontaneous endometriosis in an umbilical skin lesion.

Cutaneous endometriosis of the umbilicus is an unusual condition with unclear pathogenetic mechanisms that might be mistaken for a malignant condition. A 46-year-old woman presented with a cutaneous black mass in the umbilicus. The lesion was removed surgically and histological analyses revealed that it consisted of endometrial tissue. There was no recurrence at 18-month follow-up. Endometriosis of the umbilicus is a rare condition and the pathogenesis is not completely elucidated. According to one theory, intraperitoneal endometrial tissue is translocated during endoscopic surgery or other surgical procedures that involve the umbilicus. However, in this case there was no history of abdominal wall surgery. We conclude that endometriosis is important to consider in cases of unclear skin lesions of the umbilicus, even in cases with no previous abdominal surgery. Moreover, umbilical endometriosis of the skin can have different appearances that resemble malignant tumors, and radical surgery with histology is therefore indicated.

Sitting can cause ischaemia in the subcutaneous tissue of the buttocks, which implicates multilayer tissue damage in the development of pressure ulcers.

A better understanding of how pressure ulcers develop in the buttocks will improve prophylactic measures. Our aim was to investigate signs of reduced perfusion and ischaemia in the subcutaneous fat in the buttocks during sitting. A microelectrode was used to quantify oxygen (pO(2)). Metabolites that indicate aerobic or anaerobic metabolism (glucose, lactate, pyruvate, and glycerol) were quantified using microdialysis. Sixteen healthy people were studied while they sat on a wheel chair cushion, and a hard surface. Sitting pressures were mapped, and the thickness of the subcutaneous fatty layer was measured. The results showed that pO(2) and glucose were significantly reduced during sitting, and for pO(2) the effect is significantly more profound during sitting on a hard surface. After loading, both glucose and pO(2) increased significantly. We conclude that the subcutaneous adipose tissue covering the ischial tuberosities becomes ischaemic during sitting. This finding supports the theory that not only is the skin involved in early development of pressure ulcers, but also the deeper tissues.

Three Years' Experience of a Novel Biosynthetic Cellulose Dressing in Burns.

Objective: The use of porcine xenograft (PX) is widely spread in burn care. However, it may cause immunologic responses and other ethical and cultural considerations in different cultures. Therefore, there is a need for alternatives. The aim of this work is to test a novel biosynthetic cellulose dressing (Epiprotect®) on burn patients. Approach: Charts from 38 patients with superficial burns (SBs) (n = 18) or excised burns (n = 20) that got biosynthetic cellulose dressing instead of PX at a national burn center during 3 years were reviewed. Time to healing, length of stay, and wound infection were extracted from the medical records. Results: SBs hospitalization time was 11 days comparable to PXs reported by others. In the excised group, median duration of hospital stay was 35 days. Time to healing was 28 days. Seven wound infections were confirmed in the superficial group (39%) and 11 infections in the excised group (61%). Patients with superficial wounds reported pain relief on application. Innovation: A dressing (17 × 21 cm) consisting of biosynthetic cellulose replacing PX. Conclusion: Outcome of treatment of SBs or temporary coverage of excised deep burns with biosynthetic cellulose is comparable to treatment with PX. However, biosynthetic cellulose has benefits such as providing pain relief on application and ethical or cultural issues with the material is nonexistent.

Superiority of silver-foam over porcine xenograft dressings for treatment of scalds in children: A prospective randomised controlled trial.

AIM: Our aim was to compare two different regimens for the treatment of children with partial-thickness scalds. These were treated with either a porcine xenograft (EZderm®, Mölnlycke Health Care, Gothenburg, Sweden) or a silver-foam dressing (Mepilex® Ag, Mölnlycke Health Care, Gothenburg, Sweden). METHODS: We organised a prospective randomised clinical trial that included 58 children admitted between May 2015 and May 2018 with partial-thickness scalds to The Burn Centre in Linkoping, Sweden. The primary outcome was time to healing. Secondary outcomes were pain, need for operation, wound infection, duration of hospital stay, changes of dressings, and time taken. RESULTS: The patients treated with silver-foam dressing had a significantly shorter healing time. The median time to 97% healing for this group was 9 (7-23) days compared to 15 (9-29) days in the porcine xenograft group (p = 0.004). The median time to complete healing for the silver-foam group was 15 (9-29) days and for the porcine xenograft group 20.5 (11-42) days (p = 0.010). Pain, wound infection, duration of hospital stay, and the proportion of operations were similar between the groups. Number of dressing changes and time for dressing changes were lower in the silver-foam dressing group (p = 0.03 for both variables). CONCLUSIONS: We compared two different treatments for children with partial-thickness scalds, and the data indicate that wound healing was faster, fewer dressing changes were needed, and dressing times were shorter in the silver-foam group.

Burned patients who die from causes other than the burn affect the model used to predict mortality: a national exploratory study.

INTRODUCTION: The Baux score - the sum of age and total body surface area burned (TBSA %) - is a good predictor of mortality has a high specificity but low sensitivity. Our aim was to examine the causes of death in patients who die with Baux scores of <100, which may explain the lower sensitivity and possibly affect the prediction of mortality. METHODS: All patients admitted to our centre for burn care from 1993 to 2015 (n=1946) were included in this retrospective, descriptive, exploratory study. The study group comprised those patients who died with Baux scores of <100 (n=23), and their medical charts were examined for the cause of death and for coexisting diseases. RESULTS: Crude mortality was 5% (93/1946) for the overall cohort, and a quarter of the patients who died (23/93) had Baux scores of less than 100 (range 64-99). In this latter group, flame burns were the most common (18/23), the median (10th-90th centile) age was 70 (46-86) years and for TBSA 21 (5.0-40.5) %, of which 7 (0-27.0) % of the area was full thickness. The main causes of death in 17 of the 23 were classified as "other than burn", being cerebral disease (n=9), cardiovascular disease (n=6), and respiratory failure (n=2). Among the remaining six (burn-related) deaths, multiple organ failure (predominantly renal failure) was responsible. When we excluded the cases in which the cause of death was not related to the burn, the Baux mortality prediction value improved (receiver operating characteristics area under the curve, AUC) from 0.9733 (95% CI 0.9633-0.9834) to 0.9888 (95% CI 0.9839-0.9936) and the sensitivity estimate increased from 45.2% to 53.9%. CONCLUSION: Patients with burns who died with a Baux score <100 were a quarter of all the patients who died. An important finding is that most of these deaths were caused by reasons other than the burn, usually cerebrovascular disease. This may be the explanation why the sensitivity of the Baux score is low, as factors other than age and TBSA % explain the fatal outcome.

Perfusion of buttock skin in healthy volunteers after long and short repetitive loading evaluated by laser Doppler perfusion imager.

Frequent unloading is vital to avoid pressure ulcers of the seat area in patients with injuries to the spinal cord. The duration of unloading is probably as important as that of the sitting period in the prophylaxis of pressure ulcers. The aim of this study was to investigate the microcirculatory reactions after occlusion of the buttock skin after repeated ischaemic provocation. The perfusion of buttock skin was studied with a laser Doppler perfusion imager (LDPI) in healthy people after short and long periods of sitting (repeated four times). The perfusion increased significantly during the consecutive loadings compared with the first loading, and this effect was more profound after the long load. Repeated periods of ischaemia of the buttock skin without allowing the tissues to recover resulted in increasing reactive hyperaemia, and are therefore probably more damaging than single loadings. This is important when establishing clinical guidelines for the prophylaxis of pressure ulcers in patients with spinal cord injuries.

Staged excisions of moderate-sized burns compared with total excision with immediate autograft: an evaluation of two strategies.

BACKGROUND: Different surgical techniques have evolved since excision and autografting became the treatment of choice for deep burns in the 1970s. The treatment plan at the Burn Center, Linköping University Hospital, Sweden, has shifted from single-stage excision and immediate autografting to staged excisions and temporary cover with xenografts before autografting. The aim of this study was to find out if the change in policy resulted in extended duration of hospital stay/total body surface area burned (LOS/TBSA%). METHODS: Retrospective clinical cohort including surgically-managed patients with burns of 15%-60% TBSA% within each treatment group. The first had early full excisions of deep dermal and full thickness burns and immediate autografts (1997-98), excision and immediate autograft group) and the second had staged excisions before final autografts using xenografts for temporary cover (2010-11, staged excision group). RESULTS: The study included 57 patients with deep dermal and full-thickness burns, 28 of whom had excision and immediate autografting, and 29 of whom had staged excisions with xenografting before final autografting. Adjusted (LOS/TBSA%) was close to 1, and did not differ between groups. Mean operating time for the staged excision group was shorter and the excised area/operation was smaller. The total operating time/TBSA% did not differ between groups. CONCLUSION: Staged excisions with temporary cover did not affect adjusted LOS/TBSA% or total operating time. Staged excisions may be thought to be more expensive because of the cost of covering the wound between stages, but this needs to be further investigated as do the factors that predict long term outcome.

Long-term survival after burns in a Swedish population.

INTRODUCTION: As widely reported, the progress in burn care during recent decades has reduced the hospital mortality. The effect of the burns on long-term outcome has not received so much attention, and more study is indicated. The aim of this retrospective study was to investigate the long-time survival among patients who had been treated for burns. METHODS: We studied 1487 patients who were discharged alive from the Linköping University Hospital Burn Centre during the period 1993 until the end of December 2012. We used Cox's regression analysis to study the effect of burns on long-term survival after adjustment for different factors. RESULTS: Age and a full-thickness burn were significantly associated with mortality after discharge (p<0.001), whereas percentage of total body surface area burned (TBSA %), need for mechanical ventilation, and gender were not. Less than 1% of the patients with burns (13/1487) died within 30 days of discharge and a total of 176/1487 (12%) died during follow-up. CONCLUSION: Age and full-thickness burns reduce the long-time survival after discharge from the Burn Centre, whereas the effect of TBSA% and need for artificial ventilation ends with discharge.

Perfusion of the skin of the buttocks in paraplegic and tetraplegic patients, and in healthy subjects after a short and long load.

In patients with spinal cord injuries (n=8) and healthy controls (n=8) the hyperaemic response in the buttock skin after sitting on a hard surface was studied using a laser Doppler perfusion imager. They sat for three minutes (short load), or 15 minutes (long load). An exponential mathematical function was used to compare the mean perfusion during the observed interval. The results showed that preloading perfusion is significantly higher among patients than healthy subjects. In both groups, the microcirculation of the skin increased significantly after loading, and peak perfusion was significantly lower after the short load. The mean perfusion was higher among the patients after both loadings, which suggests that there was stronger ischaemic provocation. The main outcome was that there was a dose-response relation between duration of loading and intensity of reactive hyperaemia, and that patients with spinal cord injuries have greater perfusion before and after loading than healthy controls.

Laser Doppler perfusion imaging of the radial forearm flap: a clinical study.

Laser Doppler perfusion imaging (LDPI) allows non-invasive assessment of blood flow in a predefined area of skin rather than at one single point. We have used LDPI to study the pattern of skin blood flow in the radial forearm flap before and after the flap has been raised. The data were collected from a consecutive series of 11 patients with cancer of the oral cavity or oropharynx in whom the radial forearm flap had been used during the reconstructive procedure. Reperfusion leads to an immediate hyperaemic response both in the flap and the surrounding skin. This hyperaemia remains for at least the first 30 minutes after reperfusion. The perfusion of the radial side of the forearm skin distal to the flap is significantly lower than that on the ulnar side after the skin island has been raised and the distal artery divided. We suggest that LDPI is useful for monitoring the perfusion of free skin flaps.

Treatment of Children With Scalds by Xenografts: Report From a Swedish Burn Centre.

Scalds are the most common type of burn in children, and one way to treat them is with xenografts with no topical antimicrobials in line with the recommendations of a recent review. However, this treatment has not been examined in detail. Our aim was to describe the treatment of such children when biological dressings (xenografts) were used without local antimicrobials. We reviewed the medical records of all children admitted to a Swedish National Burn Centre during the period 2010-2012 with scalds who were treated with xenografts. Percentage TBSA injured, age, length of hospital stay, number of operations, antibiotics given, duration of antibiotic treatment, and pain score during the first 3 days, application of xenografts, and clinical notes of wound infection were recorded. We studied 67 children, (43 of whom were boys), with a median (interquartile range [IQR]) age of 1 (1-2) year and median (IQR) TBSA% 6.2 (4-11). Twenty children (30%) required operation. Twelve (18%) developed a wound infection, 29 (43%) had other infections, and 26 (39%) were free from infection. The median (IQR) duration of systemic antibiotics was 10 (6-13) days. On the day that the xenografts were applied 10 of the children had a Face, Legs, Activity, Cry, and Consolability (FLACC) score between 3 and 7, and during the following 2 days, only four children scored in this range. The remaining 57 children had scores < 3 on the day that xenografts were applied and on the following 2 days. Median (IQR) length of stay/TBSA% was 0.7 (0.4-1.0). Treatment with xenografts was associated with median length of stay/TBSA% <1 and low pain scores. Despite a high rate of prescription of systemic antibiotics, most were for reasons other than wound infection.

Sitting pressure and perfusion of buttock skin in paraplegic and tetraplegic patients, and in healthy subjects: a comparative study.

The distribution of sitting pressure and ability to respond with reactive hyperaemia were studied in a group of paraplegic and tetraplegic patients (n = 8) with spinal cord lesions and healthy controls (n = 10) using a pressure sensitive plate and laser Doppler perfusion imager. The results show that the mean sitting pressure of the patients was 9.9 N/cm2 (left) and 11.7 N/cm2 (right) compared with 3.5 N/cm2 (left) and 3.6 N/cm2 (right) in controls. The differences were significant on both the left (p < 0.01) and right (p < 0.05) sides. The maximum pressure in patients was 42.9 N/cm2 (left) and 48.7 N/cm2 (right), and in controls 12.0 N/cm2 (left) and 12.9 (right) (p < 0.01). Both groups showed a reduction in skin perfusion in the seat area during sitting compared with unloaded resting, and in the controls it was significantly increased (p < 0.001 on both sides) during the reactive hyperaemic phase immediately after sitting. Compared with the preload values, the patients showed a similar but slightly weaker picture significant on the right side (p < 0.05), but not on the left. The hyperaemia was not uniformly distributed, but occurred where the pressure was greater than 2 N/cm2. There was no correlation between the amount of reactive hyperaemia and absolute values of sitting pressures. We conclude that tetraplegic and paraplegic patients have significantly higher sitting pressures than normal controls, and that the hyperaemic response in the buttock region in the upright position after pressure load is slightly weaker in the patients, which could be of importance for the development of decubitus ulcers.

Simulation-assisted burn disaster planning.

The aim of the study was to evaluate the Swedish medical systems response to a mass casualty burn incident in a rural area with a focus on national coordination of burn care. Data were collected from two simulations of a mass casualty incident with burns in a rural area in the mid portion of Sweden close to the Norwegian border, based on a large inventory of emergency resources available in this area as well as regional hospitals, university hospitals and burn centres in Sweden and abroad. The simulation system Emergo Train System(®) (ETS) was used and risk for preventable death and complications were used as outcome measures: simulation I, 18.5% (n=13) preventable deaths and 15.5% (n=11) preventable complications; simulation II, 11.4% (n=8) preventable deaths and 11.4% (n=8) preventable complications. The last T1 patient was evacuated after 7h in simulation I, compared with 5h in simulation II. Better national coordination of burn care and more timely distribution based on the experience from the first simulation, and possibly a learning effect, led to a better patient outcome in simulation II. The experience using a system that combines both process and outcome indicators can create important results that may support disaster planning.

Flexor tendon tissue engineering: acellularization of human flexor tendons with preservation of biomechanical properties and biocompatibility.

OBJECTIVE: Acellular human tendons are a candidate scaffold for tissue engineering flexor tendons of the hand. This study compared acellularization methods and their compatibility with allogeneic human cells. METHOD: Human flexor tendons were pretreated with 0.1% ethylenediaminetetracetic acid (EDTA) for 4 h followed by 24 h treatments of 1% Triton X-100, 1% tri(n-butyl)phosphate, or 0.1% or 1% sodium dodecyl sulfate (SDS) in 0.1% EDTA. Outcomes were assessed histologically by hematoxylin and eosin and SYTO green fluorescent nucleic acid stains and biochemically by a QIAGEN DNeasy kit, Sircol collagen assay, and 1,9 dimethylmethylene blue glycosaminoglycan assay. Mechanical data were collected using a Materials Testing System to pull to failure tendons acellularized with 0.1% SDS. Acellularized tendons were re-seeded in a suspension of human dermal fibroblasts. Attachment of viable cells to acellularized tendon was assessed biochemically by a cell viability assay and histologically by a live/dead stain. Data are reported as mean±standard deviation. RESULT: Compared with the DNA content of fresh tendons (551±212 ng DNA/mg tendon), only SDS treatments significantly decreased DNA content (1% SDS [202.8±37.4 ng DNA/mg dry weight tendon]; 0.1% SDS [189±104 ng DNA/mg tendon]). These findings were confirmed by histology. There was no decrease in glycosaminoglycans or collagen following acellularization with SDS. There was no difference in the ultimate tensile stress (55.3±19.2 [fresh] vs. 51.5±6.9 [0.1% SDS] MPa). Re-seeded tendons demonstrated attachment of viable cells to the tendon surface using a viability assay and histology. CONCLUSION: Human flexor tendons were acellularized with 0.1% SDS in 0.1% EDTA for 24 h with preservation of mechanical properties. Preservation of collagen and glycoaminoglycans and re-seeding with human cells suggest that this scaffold is biocompatible. This will provide a promising scaffold for future human flexor tendon tissue engineering studies to further assess biocompatibility through cell proliferation and in vivo studies.

Flexor tendon tissue engineering: temporal distribution of donor tenocytes versus recipient cells.

BACKGROUND: Tissue-engineered tendon material may address tendon shortages in mutilating hand injuries. Tenocytes from rabbit flexor tendon can be successfully seeded onto acellularized tendons that are used as tendon constructs. These constructs in vivo exhibit a population of tenocyte-like cells; however, it is not known to what extent these cells are of donor or recipient origin. Furthermore, the temporal distribution is also not known. METHODS: Tenocytes from New Zealand male rabbits were cultured and seeded onto acellularized rabbit forepaw flexor tendons (n = 48). These tendon constructs were transplanted into female recipients. Tendons were examined after 3, 6, 12, and 30 weeks using fluorescent in situ hybridization to detect the Y chromosome in the male donor cells. One unseeded, acellularized allograft in each animal was used as a control. RESULTS: The donor male tenocytes populate the epitenon and endotenon of the grafts at greater numbers than the recipient female tenocytes at 3 and 6 weeks. The donor and recipient tenocytes are present jointly in the grafts until 12 weeks. At 30 weeks, nearly all cells are recipient tenocyte-like cells. CONCLUSIONS: Donor male cells survive in decreasing numbers over time until 30 weeks. The presence of cells in tissue-engineered tendon grafts has been shown in prior studies to add to the strength of the constructs in vitro. This study shows that recipient cells can migrate into and repopulate the tendon construct. Cell seeding onto tendon material may create stronger constructs that will allow the initiation of motion earlier.

Intravesical self-tying knots in suprapubic catheters: a report of two cases.

We present two cases in which intravesical, self-tying knots occurred when the Cystofix catheter was used for suprapubic catheterization in two male boys admitted for hypospadias surgery. This complication of suprapubic catheterization is most likely due to the pigtail end of the catheter, and should be considered when removal is difficult.