Radiotherapy and wound healing

Outcomes and Complications for Concurrent Hernia Repair Among Women Undergoing Hysterectomy

OBJECTIVE

To assess whether concurrent hernia repair at time of hysterectomy is associated with increased complications.

METHODS

In this retrospective cohort study, patients who underwent hysterectomy and hysterectomy with concurrent hernia repair were queried using the American College of Surgeons' National Surgical Quality Improvement Program participant use file (2005-2019). Propensity score matching was performed 1:1 with respect to preoperative and operative characteristics. Outcomes were operation time, length of stay (LOS), and major and minor complications. A secondary analysis of patients who underwent hysterectomy for malignancy was performed.

RESULTS

A total of 369,010 patients underwent hysterectomy, and 5,071 of those underwent hysterectomy with concurrent hernia repair. After propensity score matching, there were 5,071 patients in each arm. Hysterectomy with concurrent hernia repair had a longer operation time by 46 minutes (95% CI 42.6-49.6; P <.001) and longer LOS after surgery by 0.71 days (95% CI 0.59-0.84; P <.001). Hysterectomy with concurrent hernia repair was associated with a 21.9% higher risk (15.6% vs 12.8%; 95% CI 1.11-1.34, P <.001) of major complications and was associated with a 34.5% higher risk (7.4% vs 5.5%; 95% CI 1.16-1.56, P <.001) of minor complications. In subgroup analyses, there was no significant increase in risk among patients with body mass indexes (BMIs) lower than 40, those who were younger than age 40 years or older than age 60 years, and those with tobacco use, diabetes, or a minimally invasive surgical approach. For patients undergoing hysterectomy for malignancy, hysterectomy with concurrent hernia repair was associated with a 32-minute longer operation time (95% CI 25.2-38.8; P <.001) and a 0.35-day longer LOS (95% CI 0.04-0.67, P =.027), but there was no significant difference in major and minor complications.

CONCLUSION

Hysterectomy with concurrent hernia repair is associated with increased operation time, LOS, and risk of major and minor complications compared with hysterectomy without hernia repair. The subgroup analyses suggest that hysterectomy with concurrent hernia has a similar complication risk as hysterectomy without hernia repair in select populations, such as those with BMIs lower than 40 or with known malignancy.

An obstetrician-gynecologist's review of hernias: risk factors, diagnosis, prevention, and repair

Management of obstetrical and gynecologic patients with hernias poses challenges to providers. Risks for hernia development include well-described factors that impair surgical wound healing and increase abdominal pressure. Among the diverse populations cared for by obstetricians and gynecologists, pregnant patients and those with gynecologic malignancies are at the highest risk for hernia formation. This article provides an overview of the existing literature, with a focus on patients cared for by obstetrician-gynecologists and commonly encountered preoperative and intraoperative scenarios. We highlight scenarios when a hernia repair is not commonly performed, including those of patients undergoing nonelective surgeries with known or suspected gynecologic cancers. Finally, we offer multidisciplinary recommendations on the timing of elective hernia repair with obstetrical and gynecologic procedures, with attention to the primary surgical procedure, the type of preexisting hernia, and patient characteristics.

Phase I study of neoadjuvant S-1 plus cisplatin with concurrent radiation for biliary tract cancer (Tokyo Study Group for Biliary Cancer: TOSBIC02)

Aim

Neoadjuvant chemoradiotherapy may improve survival in patients with advanced cholangiocarcinoma. This Phase I study aimed to determine the recommended dose of neoadjuvant chemoradiotherapy and decide whether to move to a Phase II study.

Methods

Patients diagnosed with resectable stage II-IVa cholangiocarcinoma were administered cisplatin (40 [level 0], 50 [level 1 as starting dose], or 60 [level 2] mg/m2), 80 mg/m2 of S-1, and 50.4 Gy of external beam radiation. The recommended dose was defined as a dose one-step lower than the maximum-tolerated dose, which was defined when dose-limiting toxicity was observed in three or more of the six patients.

Results

Twelve patients were eligible from November 2012 to May 2016. Ten patients had perihilar cholangiocarcinoma and two patients had distal cholangiocarcinoma. Dose-limiting toxicity was observed in one of the first six patients at level 1 and two of the next six patients at level 2; thus, the maximum-tolerated dose was not determined even at level 2 and the recommended dose was determined as level 2. Four patients had partial response, four patients had stable disease, and two patients had progression of disease because of liver metastases. Finally, nine patients underwent radical surgery and seven cases achieved R0 resection. However, five cases suffered biliary leakage and one suffered intrahospital death due to rupture of the hepatic artery.

Conclusion

We determined the recommended dose of neoadjuvant chemoradiotherapy for resectable cholangiocarcinoma. However, we terminated the trial due to a high incidence of morbidity and unexpected mortality.

External beam radiotherapy inhibits stent related granulation hyperplasia in rabbit trachea

Endobronchial stent exacerbates the formation of granulation tissue. Radiotherapy maybe a durable treatment option for granulation hyperplasia. In this study, we explore the results of external beam radiotherapy (EBRT) for granulation hyperplasia after airway stent placement. A total of 30 New Zealand rabbits were assigned in three groups, Control group (n = 12), low dosage (LD, 12 Gy in 4 fractions and twice a week) group (n = 9) and high dosage (HD, 20 Gy in 4 fractions and twice a week) group (n = 9). Post-stenting 1 week, LD and HD group started to receive EBRT. Bronchoscopy, Haematoxylin-eosin (HE), Masson's trichrome (MTS), Safranin O (SO) and immunohistochemical (IHC) staining protocols were performed to evaluate the histopathological changes of trachea. A total of 30 stents were successfully implanted in 30 rabbits. No procedure-related death and complications happened. Post-stenting 4 w, 8 w and 12 w, the ventilate area ratio (VAR) and qualitative histological scoring (QHS) in the LD group and HD group lower than the Control group. Post-stenting 12w, the immunohistochemical results revealed that the positive percentage of TGF-β and VEGF in the LD group and HD group were lower than the Control group. In conclusion, the present study investigated the efficacy of EBRT in reducing stent related granulation tissue formation in the rabbit trachea. Higher dosage EBRT with a better result in inhibiting granulation hyperplasia.

Design and Synthesis of a Mitochondria-Targeting Radioprotectant for Promoting Skin Wound Healing Combined with Ionizing Radiation Injury

Wound healing is seriously retarded when combined with ionizing radiation injury, because radiation-induced excessive reactive oxygen species (ROS) profoundly affect cell growth and wound healing. Mitochondria play vital roles not only as cellular energy factories but also as the main source of endogenous ROS, and in this work a mitochondria-targeting radioprotectant (CY-TMP1) is reported for radiation injury-combined wound repair. It was designed, synthesized and screened out from different conjugates between mitochondria-targeting heptamethine cyanine dyes and a peroxidation inhibitor 2,2,6,6-tetramethylpiperidinyloxy (TEMPO). CY-TMP1 specifically accumulated in mitochondria, efficiently mitigated mitochondrial ROS and total intracellular ROS induced by 6 Gy of X-ray ionizing irradiation, thereby exhibiting a notable radioprotective effect. The mechanism study further demonstrated that CY-TMP1 protected mitochondria from radiation-induced injury, including maintaining mitochondrial membrane potential (MMP) and ATP generation, thereby reducing the ratio of cell apoptotic death. Particularly, an in vivo experiment showed that CY-TMP1 could effectively accelerate wound closure of mice after 6 Gy of whole-body ionizing radiation. Immunohistochemical staining further indicated that CY-TMP1 may improve wound repair through angiogenesis and re-epithelialization. Therefore, mitochondria-targeting ROS scavengers may present a feasible strategy to conquer refractory wound combined with radiation injury.

A Chitosan-Coated Chamomile Microparticles Formulation to Prevent Radiodermatitis in Breast: A Double-blinded, Controlled, Randomized, Phase II Clinical Trial

PURPOSE

The aim was to evaluate the effect of a topical formulation containing chitosan-coated Chamomilla recutita (L.) rauschert microparticles regarding the incidence, grade, and days for the appearance of radiodermatitis (RD) in women with breast cancer.

METHODS

A double-blinded, controlled, randomized, phase II clinical trial developed with women diagnosed with breast cancer who will receive radiation therapy. The participants were randomly divided into 2 groups: control and treatment. They were followed up until the end of the treatment or the appearance of grade III RD.

RESULTS

Fifty-four women were included in the study. There is no significant difference between the groups in the incidence (88.9% vs. 88.9%, P=1.0) or time to develop any grade of RD (3 days of difference, P=0.300). A significant reduction was observed in the incidence (P=0.03) and in the time to appearance (7 d of difference, P=0.01) grade 2 or >RD. In the follow-up evaluation (15 d after the end of treatment), the Chamomile group presented a superior skin recovery than the control group (P=0.0343). High-intensity local symptoms as pain, and pruritus were significantly reduced in the Chamomile group.

CONCLUSIONS

Although no effect was observed with chamomile to reduce any grade of RD, it was effective to reduce grade 2 or >toxicity, to improve skin recovery and to diminish high-intensity local symptoms.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (ReBEC): RBR-9hnftg, April 29, 2019.

A Case of Squamous Cell Carcinoma of the Nasal Cavity Treated With Total Rhinectomy

Squamous cell carcinoma of the nasal cavity is a relatively rare cancer. Five-year recurrence-free survival rates have a large range, which may be due to the small patient population available to study. Recurrence rates vary based on the treatment regimen and aggressiveness of the surgical approach. Total rhinectomy is not often performed due to its invasive nature and extensiveness of reconstruction required afterward. This report will cover a patient who presented with squamous cell carcinoma of the left nasal vestibule and was treated with total rhinectomy and radiation therapy. 

Risk Factors for Failure of Hard Palate Mucoperiosteal Flap Repair of Acquired Oronasal Communication in Dogs: A Pilot Study

The objective of this retrospective pilot study was to describe potential risk factors for failure of hard palate mucoperiosteal flaps (HPF) transposed for closure of oronasal communication. Dogs (n = 28) with acquired oronasal communication defects were included in the study population. Functional success of an HPF was determined by visual inspection at the last examination and lack of clinical signs. Risk factors for HPF failure including age, sex, body weight, presence of neoplasia at the time of surgery, presence of neoplasia after surgery due to incomplete or narrow margins, use of CO₂ laser, previous surgeries in the same location, HPF blood supply, size of the HPF as a percentage of the total area of the hard palate mucoperiosteum, and distance traveled by the apex of the HPF were evaluated using descriptive statistics and unadjusted logistic regression modeling. Seven out of 28 (25%) hard palate flap procedures resulted in persistent oronasal communication and were considered failures. Body weight (Median: 17 vs. 25 kg, OR = 0.94, 80% CI = 0.90, 0.99), presence of neoplasia at the time of surgery (86 vs. 57%, OR = 4.50, 80% CI = 1.01, 20.06), HPF area (Median: 0.49 vs. 0.41, OR = 84.40, 80% CI = 1.66, 4,298) and apex travel distance (Median: 2.06 vs. 0.67, OR = 5.15, 80% CI = 2.14, 12.38) were associated with flap failure. Within this sample, the presence of neoplasia at the time of initial surgery, increasing the area of the HPF, and distance traveled by the HPF apex were associated with a greater odds of HPF failure. Further studies with larger sample sizes are needed to confirm repeatability of these results. HPFs remain a viable surgical option for closure of oronasal communication. Careful surgical planning, strict adherence to surgical principles, and awareness of anatomical limitations can increase the likelihood of success.

Long-term Effect of Individualized Titanium Mesh in Orbital Floor Reconstruction After Maxillectomy

OBJECTIVE

The aim of this study was to determine the clinical outcomes and long-term stability of individualized titanium mesh combined with free flap for orbital floor reconstruction after maxillectomy and to identify the risk factors for titanium mesh exposure.

MATERIAL AND METHODS

The data of 66 patients who underwent maxillectomy and orbital floor defect reconstruction by individualized titanium mesh in Peking University School and Hospital of Stomatology between 2011 and 2019 were retrospectively reviewed. Postoperative ophthalmic function and success of aesthetic restoration were assessed. Titanium mesh exposure was recorded and the risk factors were identified.

RESULTS

Mean follow-up was for 24.8 months (range, 6-92 months). Ophthalmic function was successfully restored in 63/66 patients. Aesthetic restoration was not considered satisfactory by 10 patients. Titanium mesh exposure occurred in six patients (exposure rate, 9.1%). Preoperative radiotherapy was identified as an independent risk factor for mesh exposure (OR = 28.8, P = 0.006). Previous surgery, postoperative radiotherapy, pathological type of the primary lesion, the type of tissue flap applied, and the use of intraoperative navigation were not significant risk factors. Six patients with titanium mesh exposure underwent second surgery, but mesh exposure recurred in two patients due to insufficient soft tissue coverage.

CONCLUSION

Individualized titanium mesh with free flap can effectively restore maxilla-orbital defects. Preoperative radiotherapy is an independent predictor of postoperative titanium mesh exposure. Adequate soft tissue coverage of the mesh may reduce the risk of mesh exposure.

LEVEL OF EVIDENCE

Level 4 (case-control study) Laryngoscope, 2021.

Lower Urinary Tract Symptoms in Prostate Cancer Patients Treated With Radiation Therapy: Past and Present

The incidence of prostate cancer (PCa) is increasing concomitantly with population aging. Accordingly, interest in radiation therapy (RT) and the frequency of RT are also increasing. The types of RT can be broadly divided into external beam RT (EBRT), brachytherapy (BT), and combination therapy (EBRT+BT). Lower urinary tract symptoms (LUTS) after RT for the treatment of PCa are common; however, there are few reviews on the relationship between RT and LUTS. Herein, we review the causes and incidence of LUTS, as well as the evaluation and treatment options. Because of the reported risks of RT, patients undergoing RT should be counseled regarding the challenges of treatment and informed that they may have higher failure rates than nonirradiated patients. Moreover, thorough evaluation and treatment strategies are needed to support treatment recommendations. With a review of the existing literature, this narrative article provides an overview to aid urologists in treating patients presenting with complications associated with RT for the treatment of PCa. Further research is required to provide evidence of the effectiveness and feasibility of the management approach to the care of patients with LUTS after RT for the treatment of PCa.

Advanced co-culture 3D breast cancer model for investigation of fibrosis induced by external stimuli: optimization study

Radiation-induced fibrosis (RIF) is the main late radiation toxicity in breast cancer patients. Most of the current 3D in vitro breast cancer models are composed by cancer cells only and are unable to reproduce the complex cellular homeostasis within the tumor microenvironment to study RIF mechanisms. In order to account complex cellular interactions within the tumor microenvironment, an advanced 3D spheroid model, consisting of the luminal breast cancer MCF-7 cells and MRC-5 fibroblasts, was developed. The spheroids were generated using the liquid overlay technique in culture media into 96-well plates previously coated with 1% agarose (m/v, in water). In total, 21 experimental setups were tested during the optimization of the model. The generated spheroids were characterized using fluorescence imaging, immunohistology and immunohistochemistry. The expression of ECM components was confirmed in co-culture spheroids. Using α-SMA staining, we confirmed the differentiation of healthy fibroblasts into myofibroblasts upon the co-culturing with cancer cells. The induction of fibrosis was studied in spheroids treated 24 h with 10 ng/mL TGF-β and/or 2 Gy irradiation. Overall, the developed advanced 3D stroma-rich in vitro model of breast cancer provides a possibility to study fibrosis mechanisms taking into account 3D arrangement of the complex tumor microenvironment.

A new surgical approach of direct perineal wound full-thick closure for perineal wound of abdominoperineal resection for rectal carcinoma: A prospective cohort trial

Perineal wound complications after APR have high morbidity in the colorectal surgical department. Although some approaches have been figured out to solve this clinical focus, the outcomes are still not satisfied. Herein, this prospective comparative clinical trial has been designed to evaluate a new surgical procedure of direct perineal wound full-thick closure (DPWC), compared with conventional perineal wound closure (CPWC), with hopes of making wound healing with less complications. In addition, an evaluation of an incision negative wound pressure therapy, as another focus in this field, was also analysed in the DPWC group. A total of 44 participants in our department were recruited from March 2018 to March 2020, divided into two groups randomly, CPWC group and DPWC group. The patients' characteristics, such as age, gender, BMI, smoking, alcohol consumption, comorbidities, CEA level, and high-risk of invasion, were recorded without statistical significance between the CPWC group and DPWC group. After the same standard abdominal phase, these two groups were performed in different perineal phases. And then, operative and postoperative outcomes were analysed with different statistical methods. Data on wound healing time and length of stay in the DPWC group were shorter than those in the CPWC group (P < .05). Furthermore, cases of wound infection within 30 days in the DPWC group were also less than that in the CPWC group (P < .05). However, no difference was found between the incisional negative pressure wound therapy assisted group (NPA group) and non- incisional negative pressure wound therapy assisted group (non-NPA group). During this study, hypoalbuminemia, as an independent high-risk factor, impacted perineal wound healing. (P = .0271) In conclusion, DPWC is a new surgical approach, which can lead to a better outcome than DPWC, and it can be another surgical procedure for clinicians. In addition, hypoalbuminemia should be interfered for avoiding perineal wound complications.

Outcomes of Urinary Diversion for Late Adverse Effects of Gynecologic Radiotherapy

OBJECTIVE

To describe the risks of urinary diversion performed to address adverse effects of gynecologic radiation, with the hypothesis that high grade complications would be more common in sarcopenic women and in those undergoing continent diversion (vs noncontinent) or concomitant cystectomy (vs bladder-sparing diversion).

METHODS

A retrospective review was performed of patient records of women who underwent urinary diversion for urinary adverse effects of gynecologic radiotherapy during the period of 2008-2018 from 3 tertiary centers. Skeletal muscle index was calculated to assess for sarcopenia based on preoperative computed tomography scans. Outcomes include high-grade postoperative complications within 90 days of surgery, 30-day readmission rate, and long-term (>90 days) outcomes.

RESULTS

Among 34 women who met the inclusion criteria, the majority were white/Caucasian (73.5%). Twenty-six of 34 (76.5%) underwent noncontinent diversion. Seventy nine percent (27/34) (79.4%) of women experienced complications within 90 days; 9 of 34 (26.5%) experienced high-grade (Clavien grade ≥3) complications. Thirty-two percent (11/34) were readmitted within 30 days. Rates of high-grade complications were not significantly impacted by diversion type (P = .49), concurrent cystectomy (P = .70), or sarcopenia (P = 1.0).

CONCLUSIONS

Urinary diversion for late adverse effects of gynecologic radiotherapy is associated with high peri-operative risk, even in skilled hands. In this series, neither sarcopenia, nor continent diversion, nor cystectomy were associated with increased complications. Patients and surgeons should consider risks and benefits when deciding to proceed with urinary diversion, however further study is needed to elucidate significant preoperative markers which may predispose patients to significant complications.

The use of negative pressure wound therapy in the primary setting for high-risk head and neck surgery

BACKGROUND

In head and neck surgery, dead space is typically managed by transferring a secondary pedicled flap or harvesting a larger composite flap with a muscular component. We demonstrate the novel use of prophylactic negative pressure wound therapy (NPWT) to obliterate dead space and reduce possible communication between the upper aerodigestive tract and the contents of the neck.

METHODS

We present a single-institutional case series of five patients with high-risk head and neck cancer treated with NPWT after ablative and reconstructive surgery to eliminate dead space following surgical resection.

RESULTS

All patients achieved successful wound closure following NPWT, which was applied in the secondary setting to combat infection in one patient and the primary setting to prophylactically eliminate dead space in four patients.

CONCLUSION

NPWT can be used to treat unfilled dead space in the primary setting of head and neck ablative and reconstructive surgery and help to avoid wound healing problems as well as the need for secondary flap transfers.

Fat Therapeutics: The Clinical Capacity of Adipose-Derived Stem Cells and Exosomes for Human Disease and Tissue Regeneration

Fat grafting is a well-established surgical technique used in plastic surgery to restore deficient tissue, and more recently, for its putative regenerative properties. Despite more frequent use of fat grafting, however, a scientific understanding of the mechanisms underlying either survival or remedial benefits of grafted fat remain lacking. Clinical use of fat grafts for breast reconstruction in tissues damaged by radiotherapy first provided clues regarding the clinical potential of stem cells to drive tissue regeneration. Healthy fat introduced into irradiated tissues appeared to reverse radiation injury (fibrosis, scarring, contracture and pain) clinically; a phenomenon since validated in several animal studies. In the quest to explain and enhance these therapeutic effects, adipose-derived stem cells (ADSCs) were suggested as playing a key role and techniques to enrich ADSCs in fat, in turn, followed. Stem cells - the body's rapid response 'road repair crew' - are on standby to combat tissue insults. ADSCs may exert influences either by releasing paracrine-signalling factors alone or as cell-free extracellular vesicles (EVs, exosomes). Alternatively, ADSCs may augment vital immune/inflammatory processes; or themselves differentiate into mature adipose cells to provide the 'building-blocks' for engineered tissue. Regardless, adipose tissue constitutes an ideal source for mesenchymal stem cells for therapeutic application, due to ease of harvest and processing; and a relative abundance of adipose tissue in most patients. Here, we review the clinical applications of fat grafting, ADSC-enhanced fat graft, fat stem cell therapy; and the latest evolution of EVs and nanoparticles in healing, cancer and neurodegenerative and multiorgan disease.

A triple-layered closing technique using the recti muscles to augment implant coverage in eye enucleation after maxillofacial radiotherapy: A case report

Eye enucleation (EE) of a previously irradiated orbit can lead to difficult wound closure due to the soft tissues fibrosis such as Tenon's capsule and conjunctiva. We, here, report a technique modification for EE surgery after facial radiotherapy that may decrease implant exposure by using recti muscles native tissue to reinforce the anterior implant coverage. A 71-year-old African male presented in 2003 a right orbital extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) type. He was treated with chemotherapy followed by whole orbital radiotherapy. His right vision remained impaired due to phtisis bulbi secondary to facial radiotherapy. By 2017, he developed right painful phthisis bulbi. Radiological systemic staging did not reveal any recurrence or metastasis. Because of the history of neoplasia, the right eye had to be enucleated. Due to tissue fibrosis secondary to radiotherapy, we took care to preserve as much conjunctiva and Tenon as possible. EE was performed under general anesthesia. EE consisted of a standard procedure with a modified triple-layered closing technique. The four recti muscles were attached with 5-0 Vicryl to the anterior part of the implant by passing the needle through the tunnels and tying the suture. The horizontal muscles were spread with a forceps to cover the lateral and medial part of the implant. The vertical muscles were spread with a forceps to cover the superior and the inferior part of the implant. Finally the edges of the recti muscles were sutured to each other with 5-0 Vicryl to create a muscle layer. Tenon's capsule and conjunctiva were closed separately, using horizontal interrupted 6-0 Vicryl sutures. One year after surgery, wound closure was complete with no sign of extrusion. The triple-layered closing technique using the recti muscles in EE represents a potentially viable alternative to augment implant coverage in case of Tenon and conjunctival fibrosis secondary to facial radiotherapy.

Timing of adjuvant radiation therapy and survival outcomes after surgical resection of intracranial non-small cell lung cancer metastases

OBJECTIVE

To investigate if delay of adjuvant radiotherapy (ART) beyond 6 post-operative weeks affects survival outcomes in patients undergoing craniotomy or craniectomy for resection of non-small cell lung cancer (NSCLC) intracranial metastases.

PATIENTS AND METHODS

We performed a retrospective analysis of 28 patients undergoing resection of intracranial metastases and ART at our institution from 2001 to 2016. We assessed survival outcomes for patients who received delayed versus non-delayed ART, as well as associated risk factors.

RESULTS

Among 28 patients, 8 (29%) had delayed ART beyond 6 post-operative weeks. Fifteen received stereotactic radiotherapy (SRT), 8 (29%) received whole brain radiotherapy (WBRT), and 5 (18%) received combination WBRT + SRT. There were no significant differences in ART modality or dosing, age, sex, number of intracranial metastases, primary metastasis volume, rates of chemotherapy, extracranial metastases, or post-operative functional scores between groups. Expected post-operative survival was shorter with delayed ART (7 months versus 28 months, P = 0.01). The most common reason for delayed ART was complicated post-operative course (n = 3.38%). Significant risk factors for delayed ART included non-routine discharge (P = 0.01) and additional invasive procedures between surgery and ART start date (P = 0.02).

CONCLUSIONS

Our results suggest delayed ART in patients undergoing surgical resection of intracranial NSCLC metastases is associated with shorter overall survival. However, risk factors for delayed ART, including non-routine discharge and the need for additional invasive procedures, may have in themselves reflected poorer clinical courses that may have also contributed to the observed survival differences.

Mesenchymal Stromal Cells Isolated from Irradiated Human Skin Have Diminished Capacity for Proliferation, Differentiation, Colony Formation, and Paracrine Stimulation

Ionizing radiation, commonly used in the treatment of solid tumors, has unintended but deleterious effects on overlying skin and is associated with chronic nonhealing wounds. Skin-derived mesenchymal stromal cells (SMSCs) are a pluripotent population of cells that are critically involved in skin homeostasis and wound healing. The aim of this study was to isolate and functionally characterize SMSCs from human skin that was previously irradiated as part of neoadjuvant or adjuvant cancer therapy. To this end, SMSCs were isolated from paired irradiated and nonirradiated human skin samples. Irradiated SMSCs expressed characteristic SMSC markers at lower levels, had disorganized cytoskeletal structure, and had disordered morphology. Functionally, these cells had diminished proliferative capacity and substantial defects in colony-forming capacity and differentiation in vitro. These changes were associated with significant differential expression of genes known to be involved in skin physiology and wound healing. Conditioned media obtained from irradiated SMSCs affected fibroblast but not endothelial cell proliferation and migration. These results suggest that in situ damage to SMSCs during neoadjuvant or adjuvant radiation may play a critical role in the pathogenesis of slow or nonhealing radiation wounds. Stem Cells Translational Medicine 2019;8:925&934.

Wound healing complications in oncological patients: perspectives for cellular therapy

Various types of cancer are nowadays a serious medical and social problem and a great challenge for modern medicine. The majority of anticancer therapy is based on traditional chemotherapy and radiotherapy. Both of these highly non-specific types of treatment have a number of serious side effects including wound healing complications. Radiotherapy and chemotherapy mostly affect rapidly dividing skin cells (e.g. keratinocytes), as well as fibroblasts, melanocytes, endothelial and immune cells. Currently, there are many strategies to improve wound healing in oncological patients, including various types of dressings, biomaterials, growth factors, and cell therapies.

Imaging of pH and pO2 gives insight in molecular processes of irradiated cells

One of the major challenges in radiation therapy is the interference with tissue repair processes due to hypoxic characteristics and pH dysregulation. In this study, we present dual imaging of pH and oxygenation in vitro based on luminescent biocompatible sensor foils that allow studying the effects of irradiation on different cell types in culture. Different sensitivities of fibroblast and oral squamous carcinoma cells were observed by complementing oxygen and pH differences with proliferation assays. This study highlights especially the distinct role of oxygen after irradiation and the difference in proliferation processes of irradiated normal dermal cells in contrast to irradiated tumor cells.

Incidental durotomy during total en bloc spondylectomy

BACKGROUND CONTEXT

The incidence of incidental durotomy (ID) during total en bloc spondylectomy (TES) tends to be higher than that during other spinal surgeries because of the peculiarities of TES, including its highly invasive nature, epidural tumor extension, and use in patients who often have complicated medical backgrounds. However, there have been no detailed reports on ID associated with TES.

PURPOSE

The study aimed to investigate ID during TES in detail.

STUDY DESIGN

This is a retrospective review of prospectively collected data.

PATIENT SAMPLE

The study included 105 consecutive patients with spinal tumor who underwent TES between May 2010 and February 2015 (59 men, 46 women; mean age, 54.0 years [range, 14-75 years] at the time of surgery).

OUTCOME MEASURES

Outcome measures included the incidence, risk factors, anatomical location, intraoperative maneuvers, and postoperative course of ID associated with TES.

MATERIALS AND METHODS

Medical and operative records and imaging findings were reviewed. Univariate analysis and multivariable stepwise logistic regression models were used to identify independent risk factors for ID.

RESULTS

Incidental durotomy occurred in 18 (17.1%) of the 105 patients. The univariate and multivariate analyses demonstrated that older age (adjusted odds ratio [aOR], 6.09; 95% confidence interval [CI], 1.17-31.76; p=.03), radiotherapy (RT) history (aOR, 5.31; 95% CI, 1.46-19.49; p=.01), and revision surgery (aOR, 19.42; 95% CI, 3.46-109.14; p<.01) were independent risk factors for ID. Incidental durotomy was more likely to occur during dissection of tumor tissues in proximity to the nerve root. Although all of the ID cases were primarily sutured and covered with polyglycolic acid mesh and fibrin glue spray, eight cases required additional intervention because of intractable postoperative cerebrospinal fluid leakage. Six of these eight had a history of RT.

CONCLUSIONS

Our results may help better identify high-risk patients for ID during TES, which may aid surgeons with optimal surgical decision making and in counseling patients on perioperative complications.

Practicality of using the figure-of-eight bandage to prevent fatal wound dehiscence after spinal tumor surgery for upper thoracic metastasis

OBJECT

Serious postoperative wound problems can frequently develop after surgery with perioperative RT for upper thoracic metastatic lesions. The figure-of-eight bandage can restrict excessive shoulder motion, which could prevent wound dehiscence. The purpose of this study was to describe the efficacy of using the figure-of-eight bandage to prevent postoperative wound dehiscence.

METHODS

Between February 2005 and July 2015, we retrospectively evaluated the medical records of cancer patients who underwent surgery with or without RT for spinal metastasis involving the upper thoracic spine. From January 2009, all patients received figure-of-eight bandaging immediately postoperatively, which was then maintained for 2 months. The outcome measures were the incidence and successful management of wound dehiscence following application of the figure-of-eight bandage.

RESULTS

One hundred and fifteen patients (71 men and 44 women) were enrolled in the present study. A figure-of-eight bandage in conjunction with a thoracolumbosacral orthosis (TLSO) was applied to 78 patients, while only TLSO was applied to 37 patients. The overall rate of wound dehiscence was 4.34% and the mean duration before wound dehiscence was 27.0 days (range, 22-31 days) after surgery. In the TLSO-only group, wound dehiscence occurred in four patients (10.81%), meanwhile there was only one case (1.33%) of wound dehiscence in the group that had received the figure-of-eight bandage with TLSO. Three of four patients with wound dehiscence in the TLSO only group died from unresolved wound problems and another patient was treated with wound closure followed by the application of the figure-of-eight bandage. The only patient with wound dehiscence among the patients who received both the figure-of-eight bandage and TLSO was managed by primary wound closure without further complication.

CONCLUSION

Current study suggests that the figure-of-eight bandage could prevent wound dehiscence and be used to treat wound problems easily.

Transplanted fibroblasts proliferate in host bronchial tissue and enhance bronchial anastomotic healing in a rodent model

INTRODUCTION

Healing of airway anastomoses after preoperative irradiation can be a significant clinical problem. The augmentation of bronchial anastomoses with a fibroblast-seeded human acellular dermis (hAD) was shown to be beneficial, although the underlying mechanism remained unclear. Therefore, in this study we investigated the fate of the fibroblasts transplanted to the scaffold covering the anastomosis.

MATERIAL AND METHODS

32 Fisher rats underwent surgical anastomosis of the left main bronchus. In a 2 × 2 factorial design, they were randomized to receive preoperative irradiation of 20 Gy and augmentation of the anastomosis with a fibroblast-seeded transplant. Fibroblasts from subcutaneous fat of Fischer-344 rat were transduced retrovirally with tdTomato for cell tracking. After 7 and 14 days, animals were sacrificed and cell concentration of transplanted and nontransplanted fibroblasts in the hAD as well as in the bronchial tissue was measured using RT-PCR.

RESULTS

Migration of transplanted fibroblasts from dermis to bronchus were demonstrated in both groups, irradiated and nonirradiated. In the irradiated groups, there was a cell count of 7 × 104 ± 1 × 104 tomato+-fibroblasts in the bronchial tissue at day 7, rising to 1 × 105 ± 1 × 104 on day 14 (p <0.0001). Tomato+-cell concentration in hAD increased from 6 × 103 ± 1 × 103 at day 7 to 6 × 104 ± 1 × 104 at day 14 (p <0.0001). In the nonirradiated groups, tomato+-cell concentration in bronchus was 4 × 103 ± 1 × 103 on day 7 and 4 × 103 ± 1 × 103 at day 14. In the hAD tomato+ cell concentration rising from 1 × 104 ± 1 × 103 at day 7 to 2 × 104 ± 3 × 103 cells at day 14 (p = 0.0028).

CONCLUSIONS

Transplanted fibroblasts in the irradiated groups proliferate and migrate into the irradiated host bronchial tissue, but not in the nonirradiated groups.

SKI2162, an inhibitor of the TGF-β type I receptor (ALK5), inhibits radiation-induced fibrosis in mice

Here we demonstrated that SKI2162, a small-molecule inhibitor of the TGF-β type I receptor (ALK5), prevented radiation-induced fibrosis (RIF) in mice. SKI2162 inhibited phosphorylation of Smad and induction of RIF-related genes in vitro. In RIF a mouse model, SKI2162 reduced late skin reactions and leg-contracture without jeopardizing the acute skin reaction. Irradiation of mouse tissue increased COL1A2 mRNA levels, and topical administration of SKI2162 significantly inhibited this effect. Thus, these findings support that SKI2162 has potential value as novel RIF-protective agent, and could be candidate for clinical trials.

An expression analysis of markers of radiation-induced skin fibrosis and angiogenesis in wound healing disorders of the head and neck

BACKGROUND

Radiation-induced fibrosis (RIF) is one of the severe long-term side effects of radiation therapy (RT) with a crucial impact on the development of postoperative wound healing disorders (WHD). The grades of fibrosis vary between mild to severe depending on individual radiosensitivity. In this study, we have investigated the molecular pathways that influence RIF and have correlated data from immunohistochemistry (IHC) for von -Willebrand Factor (vWF) and from Real-Time Polymerase Chain Reaction (RT-PCR) concerning markers such as Transforming Growth Factor (TGF)-β 1, and vWF, with clinical data concerning the occurrence of WHD during follow-up.

METHODS

Expression profiles of the genes encoding TGF-β 1, vWF, and α-procollagen (PC) were analyzed, by RT-PCR, in specimens from patients with (n = 20; 25.6 %) and without (n = 58; 74.4 %) a history of previous RT to the head and neck. Moreover, IHC against vWF was performed. Clinical data on the occurrence of cervical WHDs were analyzed and correlated.

RESULTS

A statistically significant increase in the expression profiles of α-PC and TGF-β 1 was observed in previously irradiated skin samples (occurrence of RT >91 days preoperatively). vWF showed a statistically significant increase in non-irradiated tissue. Moreover, analysis of expression profiles in patients with and without WHDs during follow-up was performed. IHC showed a reduced amount of vessels and structural changes in epidermal tissue post-RT.

CONCLUSIONS

The expression of markers of fibrosis and angiogenesis was analyzed in order to gain insight into molecular pathways that account for structural changes in irradiated skin and that eventually lead to WHDs. The results are congruent with reports from the literature and are a possible starting point for further research, as anti-TGF-β 1 treatment, for example, could represent new therapeutic opportunities in the management of previously irradiated patients.

Effects of Radiation on Spinal Dura Mater and Surrounding Tissue in Mice

PURPOSE

Spinal surgery in a previously irradiated field carries increased risk of perioperative complications, such as delayed wound healing or wound infection. In addition, adhesion around the dura mater is often observed clinically. Therefore, similar to radiation-induced fibrosis--a major late-stage radiation injury in other tissue--epidural fibrosis is anticipated to occur after spinal radiation. In this study, we performed histopathologic assessment of postirradiation changes in the spinal dura mater and peridural tissue in mice.

MATERIALS AND METHODS

The thoracolumbar transition of ddY mice was irradiated with a single dose of 10 or 20 Gy. After resection of the irradiated spine, occurrence of epidural fibrosis and expression of transforming growth factor beta 1 in the spinal dura mater were evaluated. In addition, microstructures in the spinal dura mater and peridural tissue were assessed using an electron microscope.

RESULTS

In the 20-Gy irradiated mice, epidural fibrosis first occurred around 12 weeks postirradiation, and was observed in all cases from 16 weeks postirradiation. In contrast, epidural fibrosis was not observed in the nonirradiated mice. Compared with the nonirradiated mice, the 10- and 20-Gy irradiated mice had significantly more overexpression of transforming growth factor beta 1 at 1 week postirradiation and in the late stages after irradiation. In microstructural assessment, the arachnoid barrier cell layer was thinned at 12 and 24 weeks postirradiation compared with that in the nonirradiated mice.

CONCLUSION

In mice, spinal epidural fibrosis develops in the late stages after high-dose irradiation, and overexpression of transforming growth factor beta 1 occurs in a manner similar to that seen in radiation-induced fibrosis in other tissue. Additionally, thinning of the arachnoid barrier cell layer was observed in the late stages after irradiation. Thus, consideration should be given to the possibility that these phenomena can occur as radiation-induced injuries of the spine.

Optimal Timing of Whole-Brain Radiation Therapy Following Craniotomy for Cerebral Malignancies

BACKGROUND

For patients with cerebral metastases that are limited in number, surgical resection followed by whole-brain radiation therapy is the standard of care. In addition, for high-grade gliomas, maximal surgical resection followed by local radiotherapy is considered the optimal treatment. Radiation is known to impair wound healing, including healing of surgical incisions. Radiotherapy shortly after surgical resection would be expected to minimize the opportunity for tumor regrowth or progression. Owing to these competing interests, the purpose of this study was to shed light on the optimal timing of radiotherapy after surgical resection of brain metastasis or high-grade gliomas.

METHODS

A review of the literature was conducted on the following topics: radiation and wound healing, corticosteroid use and wound healing, radiotherapy for tumor control for cerebral metastases and high-grade gliomas, and whole-brain radiation therapy or focal radiotherapy after craniotomy with focus on the timing of radiotherapy after surgery.

RESULTS

In animal models, wound integrity and healing was less impaired by radiotherapy administered 1 week after surgery. In humans, this timing would be expected to be significantly longer, on the order of several weeks.

CONCLUSIONS

Given the limited literature, insufficient conclusions can be drawn. However, animal data suggest a period of at least 1 week (but it is likely several weeks in humans) is necessary for reconstitution of wound strength before initiation of radiation therapy. A randomized prospective study is recommended to understand better the effect of the timing of radiation therapy following surgical intervention for brain metastasis or high-grade gliomas.

Surgical site infections among high-risk patients in clean-contaminated head and neck reconstructive surgery: concordance with preoperative oral flora

BACKGROUND

Salivary contamination of surgical wounds in clean-contaminated head and neck surgery with free flap reconstruction remains a major cause of infection and leads to significant morbidity. This study investigates the correlation between intraoral flora and surgical site infections (SSIs) among high-risk head and neck cancer patients undergoing resection and free flap reconstruction.

METHODS

One hundred twenty-nine patients were identified as being at high risk for infective complications based on cancer stage, tumor size, comorbid factors, and extent of reconstruction. All patients had intraoral swab cultures before surgery. Patients with culture-confirmed SSI after surgery were chosen for analysis, using the κ index and its 95% confidence interval for concordance analysis. All patients received clindamycin and gentamicin for antibiotic prophylaxis for 5 days. Antibiotic susceptibility testing of all isolates was obtained and analyzed.

RESULTS

Thirty-seven patients experienced SSI, or an infection rate of 28.3%, occurring at a mean of 9.3 postoperative days. The overall concordance between oral flora and SSI was fair to moderate (κ index of 0.25), but detailed analysis shows a higher concordance for known and opportunistic pathogens, such as Pseudomonas aeruginosa and Enterococcus faecalis, compared to typical oral commensals. Antibiotic susceptibility tests show rapid and significant increases in resistance to clindamycin, indicating a need for a more effective alternative.

CONCLUSIONS

Predicting pathogens in SSI using preoperative oral swabs did not demonstrate a good concordance in general for patients undergoing clean-contaminated head and neck surgery, although concordance for certain pathogenic species seem to be higher than for typical intraoral commensals. The rapid development of resistance to clindamycin precludes its use as a prophylactic agent.

Dynamics of acutely irradiated skin epidermal epithelium in swine: modeling studies

A mathematical model, which describes the dynamics of acutely irradiated skin epidermal epithelium in swine, is developed. This model embodies the key mechanisms of regulation of skin epidermal epithelium and the principal stages of development of its cells (basal, prickle, and corneal). The model is implemented as a system of nonlinear ordinary differential equations, whose variables and parameters have clear biological meaning. The modeling results for the dose- and time-dependent changes in basal and prickle cell populations are in a good agreement with relevant experimental data. The correlation between the experimental data on the dynamics of moist reaction in acutely irradiated swine skin epidermal epithelium and the corresponding modeling results on the dynamics of corneal cells is revealed. Proceeding from this, the threshold level of corneal cells, which indicates the appearance of the moist reaction, is found. All this bears witness to the validity of employment of the developed model, after appropriate identification, in the investigation and prediction of radiation effects on skin epidermal epithelium in humans.

microRNA alterations driving acute and late stages of radiation-induced fibrosis in a murine skin model

PURPOSE

Although ionizing radiation is critical in treating cancer, radiation-induced fibrosis (RIF) can have a devastating impact on patients' quality of life. The molecular changes leading to radiation-induced fibrosis must be elucidated so that novel treatments can be designed.

METHODS AND MATERIALS

To determine whether microRNAs (miRs) could be responsible for RIF, the fibrotic process was induced in the right hind legs of 9-week old CH3 mice by a single-fraction dose of irradiation to 35 Gy, and the left leg served as an unirradiated control. Fibrosis was quantified by measurements of leg length compared with control leg length. By 120 days after irradiation, the irradiated legs were 20% (P=.013) shorter on average than were the control legs.

RESULTS

Tissue analysis was done on muscle, skin, and subcutaneous tissue from irradiated and control legs. Fibrosis was noted on both gross and histologic examination by use of a pentachrome stain. Microarrays were performed at various times after irradiation, including 7 days, 14 days, 50 days, 90 days, and 120 days after irradiation. miR-15a, miR-21, miR-30a, and miR-34a were the miRs with the most significant alteration by array with miR-34a, proving most significant on confirmation by reverse transcriptase polymerase chain reaction, c-Met, a known effector of fibrosis and downstream molecule of miR-34a, was evaluated by use of 2 cell lines: HCT116 and 1522. The cell lines were exposed to various stressors to induce miR changes, specifically ionizing radiation. Additionally, in vitro transfections with pre-miRs and anti-miRs confirmed the relationship of miR-34a and c-Met.

CONCLUSIONS

Our data demonstrate an inverse relationship with miR-34a and c-Met; the upregulation of miR-34a in RIF causes inhibition of c-Met production. miRs may play a role in RIF; in particular, miR-34a should be investigated as a potential target to prevent or treat this devastating side effect of irradiation.

Perioperative complications of total en bloc spondylectomy: adverse effects of preoperative irradiation

Background

Total en bloc spondylectomy (TES) is associated with a high complication rate because it is technically demanding and involves patients compromised by cancer. Specifically, perioperative complications are more likely to occur in patients receiving preoperative irradiation. We examined the perioperative complications associated with TES in patients receiving preoperative irradiation.

Methods

Seventy-seven patients underwent TES between May 2010 and April 2013. We performed a retrospective review of prospectively collected data for 50 patients with metastatic tumors of the thoracic spine, excluding patients with primary spinal tumors, lumbar spinal metastasis, and combined anterior and posterior approach TES. Patients were divided into 2 groups: those with preoperative irradiation (RT-TES group, 18 patients) and those without preoperative irradiation (TES group, 32 patients). The following perioperative complications, occurring within 2 months of surgery, were compared between the groups: intraoperative dural injuries, epidural hematomas, deep surgical-site infections, postoperative cerebrospinal fluid leakage, wound dehiscence, pleural effusions, and neurological deficits.

Results

Significant differences in patient characteristics were not observed between the RT-TES and TES groups. Perioperative TES complications occurred in 20/50 patients (40.0%). The complication rate in the RT-TES group was 77.8% (14 out of 18), threefold higher than the 18.8% (6 out of 32) in the TES group (P<0.01). The incidence of complications, including intraoperative dural injuries, postoperative cerebrospinal fluid leakage, wound dehiscence, and pleural effusions, was significantly higher in the RT-TES group (P<0.01).

Conclusion

The perioperative complication rate associated with TES for spinal metastasis was significantly higher among patients receiving preoperative irradiation than among those not receiving preoperative irradiation.

Clinical and histological evaluation of postextraction platelet-rich fibrin socket filling: a prospective randomized controlled study

OBJECTIVES

The aims were to investigate whether the use of platelet-rich fibrin membranes (PRF) for socket filling could improve microarchitecture and intrinsic bone tissue quality of the alveolar bone after premolar extraction and to assess the influence of the surgical procedure before implant placement.

MATERIAL AND METHODS

Twenty-three patients requiring premolar extraction followed by implant placement were randomized to three groups: (1) simple extraction and socket filling with PRF, (2) extraction with mucosal flap and socket filling with PRF, and (3) controls with simple extraction without socket filling. Implant placement was performed at week 8, and a bone biopsy was obtained for histomorphometric analysis.

RESULTS

Analysis by microcomputed tomography showed better bone healing with improvement of the microarchitecture (P < 0.05) in group 1. This treatment had also a significant effect (P < 0.05) on intrinsic bone tissue quality and preservation of the alveolar width. An invasive surgical procedure with a mucosal flap appeared to completely neutralize the advantages of the PRF.

CONCLUSIONS

These results support the use of a minimally traumatic procedure for tooth extraction and socket filling with PRF to achieve preservation of hard tissue.

Promotion of wound healing using adipose-derived stem cells in radiation ulcer of a rat model

Background

Wound healing is a complex biologic process that involves the integration of inflammation, mitosis, angiogenesis, synthesis, and remodeling of the extracellular matrix. However, some wounds fail to heal properly and become chronic. Although some simulated chronic wound models have been established, an efficient approach to treat chronic wounds in animal models has not been determined. The aim of this study was to develop a modified rat model simulating the chronic wounds caused by clinical radiation ulcers and examine the treatment of chronic wounds with adipose-derived stem cells.

Results

Sprague–Dawley rats were irradiated with an electron beam, and wounds were created. The rats received treatment with adipose-derived stem cells (ASCs), and a wound-healing assay was performed. The wound sizes after ASC treatment for 3 weeks were significantly smaller compared with the control condition (p < 0.01). Histological observations of the wound edge and immunoblot analysis of the re-epithelialization region both indicated that the treatment with ASCs was associated with the development of new blood vessels. Cell-tracking experiments showed that ASCs were colocalized with endothelial cell markers in ulcerated tissues.

Conclusions

We established a modified rat model of radiation-induced wounds and demonstrated that ASCs accelerate wound-healing.

Protective effects of l-glutamine on the bladder wall of rats submitted to pelvic radiation

Radiotherapy is often used to treat prostate tumors, but the normal bladder is usually adversely affected. Using an animal model of pelvic radiation, we investigated whether glutamine nutritional supplementation can prevent radiation-induced damage to the bladder, especially in its more superficial layers. Male rats aged 3-4 months were divided into groups of 8 animals each: controls, which consisted intact animals; radiated-only rats, which were sacrificed 7 (R7) or 15 (R15) days after a radiation session (10Gy aimed at the pelvico-abdominal region); and radiated rats receiving l-glutamine supplementation (0.65g/kg body weight/day), which were sacrificed 7 (RG7) or 15 (RG15) days after the radiation session. Cells and blood vessels in the vesical lamina propria, as well as the urothelium, were then measured using histological methods. The effects of radiation were evaluated by comparing controls vs. either R7 or R15, while a protective effect of glutamine was assessed by comparing R7 vs. RG7 and R15 vs. RG15. The results showed that, in R7, epithelial thickness, epithelial cell density, and cell density in the lamina propria were not significantly affected. However, density of blood vessels in R7 was reduced by 48% (p<0.05) and this alteration was mostly prevented by glutamine (p<0.02). In R15, density of blood vessels in the lamina propria was not significantly modified. However, epithelial thickness was reduced by 25% (p<0.05) in R15, and this effect was prevented by glutamine (p<0.01). In R15, epithelial cell density was increased by 35% (p<0.02), but glutamine did not protect against this radiation-induced increase. Cell density in the lamina propria was likewise unaffected in R15. Density of mast cells in the lamina propria was markedly reduced in R7 and R15. The density was still reduced in RG7, but a higher density in RG15 suggested a glutamine-mediated recovery. Alpha-actin positive cells in the lamina propria formed a suburothelial layer and were identified as myofibroblasts. Thickness of this layer was increased in R7, but was similar to controls in RG7, while changes in R15 and RG15 were less evident. In conclusion, pelvic radiation leads to significant acute and post-acute alterations in the composition and structural features of the vesical lamina propria and epithelium. Most of these changes, however, can be prevented by glutamine nutritional supplementation. These results emphasize, therefore, the potential use of this aminoacid as a radioprotective drug.

ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context

This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

Atuação da cirurgia plástica no tratamento de feridas complexas

OBJETIVO: Relatar a atuação da Cirurgia Plástica no tratamento das feridas complexas em hospital terciário, analisando suas características, tipos de lesões e condutas adotadas, com ênfase no tratamento cirúrgico. MÉTODOS: Análise retrospectiva dos pacientes com feridas complexas atendidos pela Cirurgia Plástica em hospital terciário, através dos pedidos de consulta, em um período de cinco anos (2006 a 2010). A coleta dos dados foi obtida a partir de atendimentos realizados, avaliações seriadas e registros do prontuário médico. RESULTADOS: Foram atendidos 1927 pacientes (32 consultas/mês), com média de idade de 46,3 anos, predominando o sexo masculino (62%). As especialidades cirúrgicas solicitaram 1076 consultas (56%) e as clínicas, 851 (44%). A distribuição por tipo de ferida demonstrou predomínio das úlceras por pressão (635/33%), das feridas traumáticas (570/30%), cirúrgicas complicadas (305/16%) e necrotizantes (196/10%), sendo o restante representado por vasculite (83/4%), úlceras venosas (79/4%), diabéticas (41/2%) e pós-radiação (18/1%). O tratamento foi operatório em 1382 pacientes (72%) e não-operatório em 545 casos (28%). Nos pacientes operados, realizaram-se 3029 operações, predominando os desbridamentos (1988/65%) e enxertias de pele (619/21%) associadas ou não com a terapia por pressão negativa (vácuo), seguido pelos retalhos pediculados (237/8%), reimplantes digitais (81/3%), retalhos microcirúrgicos (66/2%) e outros procedimentos (38/1%). CONCLUSÃO: O cirurgião plástico demonstrou ter importante atuação no tratamento das feridas complexas por adotar o tratamento cirúrgico mais precocemente, colaborando para a efetiva resolução dos casos.

Acellular dermal matrix seeded with autologous fibroblasts improves wound breaking strength in a rodent soft tissue damage model in neoadjuvant settings

Soft tissue defects following resectional surgery or trauma often result in deadspaces and require free or pedicled flaps. A programmed formation of filling tissue with enhanced biomechanical properties could be helpful. This study examined the effects on wound healing of acellular dermal matrix (ADM) seeded with autologous fibroblasts in a standardized rodent model. As pre- or postoperative radiotherapy is standard in many treatments of malignancies, we also investigated the effects of additional radiotherapy. Fischer rats were randomised and received a standardized unilateral soft tissue defect at the buttock. The defect was filled with ADM+fibroblasts or ADM alone. Controls received no filling. Either no radiation, adjuvant (postoperative) or neoadjuvant (preoperative) radiation was applied to the defect site. Six weeks later the defect volume was measured by MR-tomography. Wound breaking strength was examined by tensiometry according to German Industrial Standards. Filling of the defect side was significantly larger in ADM and ADM+fibroblast treated groups compared to the control group in all settings. Wound breaking strength in the unimodal setting was significantly improved in the ADM+fibroblasts group compared to the ADM group. In the neoadjuvant setting there was no significant difference between control and ADM group. However, the ADM+fibroblasts groups showed a significantly increased wound breaking strength compared to the control and the ADM-alone group. Seeded or unseeded ADM is able to fill deadspace in this rodent model in all settings. Implanting non-irradiated, vital, proliferating autologous fibroblasts on ADM results in significantly increased wound breaking strength.