Soft Tissue Sarcoma of Extremities: Descriptive Epidemiological Analysis According to National Population-based Study

BACKGROUND

Soft-Tissue Sarcoma (STS) is a heterogeneous group of neoplasms of mesenchymal origin, occurring in connective tissues. According to previously conducted studies, STS accounts for approximately 1% and 7-%15% of adult and pediatric malignancies, respectively. Almost 50%-60% of sarcomas arise from extremities and usually present as a large painless or rarely painful soft-tissue mass. The present study aimed to describe the epidemiology of soft-tissue sarcomas, especially in the Iranian population.

METHODS

This epidemiological study of limb soft-tissue sarcoma was conducted based on Iran National Cancer Registry data (INCR) between 2009 and 2014. Patients with soft-tissue sarcoma confirmed by histopathological studies were included, and data were classified based on the International Classification of Diseases for Oncology (first revision-third edition [ICD-O-3]) and analyzed. Descriptive analysis was performed to extract age-standardized and age-specific incidence rates.

RESULTS

A total of 2, 593 patients (1,476 males and 1,117 females) were enrolled and assessed in the present study. The age-standardized incidence rate(ASIR) of total soft tissue sarcomas was 6.34 per million person-years. In addition, the highest and lowest ASIR scores stratified by age were observed in patients aged above 65 and under 0 with the value of 19.61 (95% CI:17.91-21.30) and 1.91 (95% CI 1.69, 2.13) per million, respectively. Limb soft tissue sarcomas stratified by gender were dominant in males, and it was statistically significant (P<0.05). The most common extremity soft tissue sarcomas subtypes were mesenchymal tumor (12.26%), spindle cell sarcoma (12.18%), and malignant fibrous histiocytoma (11.45%).

CONCLUSION

As evidenced by the results of the present study, the ASIR of soft tissue sarcoma dramatically increased with age, and the peak ASIR occurred in the age range of above 65 years. The incidence rate of soft tissue sarcomas analyzed by disease site was higher in hip and lower limb than upper limb and pelvis region, and it was detected consistently in all age groups and both genders.

Effect of macro-calcification on the failure mechanics of intracranial aneurysmal wall tissue

BACKGROUND

Calcification was recently found to be present in the majority of cerebral aneurysms, though how calcification and the presence or absence of co-localized lipid pools affect failure properties is still unknown.

OBJECTIVE

The primary objective is to quantify the biomechanical effect of a macro-calcification with surrounding Near-Calcification Region (NCR) of varying mechanical properties on tissue failure behavior.

METHODS

We utilized a structurally informed finite element model to simulate pre-failure and failure behavior of a human cerebral tissue specimen modeled as a composite containing a macro-calcification and surrounding NCR, embedded in a fiber matrix composite. Data from multiple imaging modalities was combined to quantify the collagen organization and calcification geometry. An idealized parametric model utilizing the calibrated model was used to explore the impact of NCR properties on tissue failure.

RESULTS

Compared to tissue without calcification, peak stress was reduced by 82% and 49% for low modulus (representing lipid pool) and high modulus (simulating increase in calcification size) of the NCR, respectively. Failure process strongly depended on NCR properties with lipid pools blunting the onset of complete failure. When the NCR was calcified, the sample was able to sustain larger overall stress, however the failure process was abrupt with nearly simultaneous failure of the loaded fibers.

CONCLUSIONS

Failure of calcified vascular tissue is strongly influenced by the ultrastructure in the vicinity of the calcification. Computational modeling of failure in fibrous soft tissues can be used to understand how pathological changes impact the tissue failure process, with potentially important clinical implications.

Augmented Reality-Assisted Biopsy of Soft Tissue Lesions

Guided biopsy of soft tissue lesions can be challenging in the presence of sensitive organs or when the lesion itself is small. Computed tomography (CT) is the most frequently used modality to target soft tissue lesions. In order to aid physicians, small field of view (FOV) low dose non-contrast CT volumes are acquired prior to intervention while the patient is on the procedure table to localize the lesion and plan the best approach. However, patient motion between the end of the scan and the start of the biopsy procedure can make it difficult for a physician to translate the lesion location from the CT onto the patient body, especially for a deep-seated lesion. In addition, the needle should be managed well in three-dimensional trajectories in order to reach the lesion and avoid vital structures. This is especially challenging for less experienced interventionists. These usually result in multiple additional image acquisitions during the course of procedure to ensure accurate needle placement, especially when multiple core biopsies are required. In this work, we present an augmented reality (AR)-guided biopsy system and procedure for soft tissue and lung lesions and quantify the results using a phantom study. We found an average error of 0.75 cm from the center of the lesion when AR guidance was used, compared to an error of 1.52 cm from the center of the lesion during unguided biopsy for soft tissue lesions while upon testing the system on lung lesions, an average error of 0.62 cm from the center of the tumor while using AR guidance versus a 1.12 cm error while relying on unguided biopsies. The AR-guided system is able to improve the accuracy and could be useful in the clinical application.

A Clinical Randomized Trial

Background:

Reduction of the soft tissue is an unavoidable consequence of tooth extraction without appropriate measures of Alveolar Ridge Preservation (ARP).

Objectives:

The objective of this study is the volumetric investigation of the dimensional change of the soft tissue post tooth extraction to compare an Alveolar Ridge Preservation (ARP) measure with the insertion of a combination material with a collagen cone to fill the alveolus, combined with a collagen membrane, with untreated extraction alveoli.

Methods:

In the context of a randomized clinical trial, 31 patients were treated with the combination material directly post tooth extraction in the maxilla (ARP). In 29 further patients, the extraction alveoli were left without further measures (control group).

The changes of the soft tissue contour were measured 6 (+/- 1) weeks post extraction. The measurements were performed by superimposing digital models. The groups were compared using the Wilcoxon rank-sum-test.

Results:

The premolar subgroup revealed a significant difference of the soft tissue dimension post insertion of a collagen material into the alveolus in comparison to untreated alveoli. In these cases, the mean loss of soft tissue volume after use of the collagen material was significantly lower.

Conclusion:

The proposed hypothesis that there is a difference of the soft tissue preservation between alveoli with and without the use of a collagen material can be accepted with restrictions to the premolar region. A statistically significant lower volume reduction of the soft tissue by implantation of the collagen material could be detected with premolars.

Modified Pedicle Grafting: A Novel Noninvasive Technique for Soft Tissue Augmentation Around Maxillary Dental Implants

OBJECTIVES

This study sought to assess the efficacy of modified pedicle grafting as a noninvasive technique for soft tissue augmentation around maxillary dental implants.

MATERIALS AND METHODS

This descriptive study was conducted on eight patients who met the inclusion criteria. Prior to the second-stage surgery for exposing the implants, the buccal keratinized mucosa width, vestibular depth, and mucosal thickness around the implants were measured. The same parameters were measured six months after the second-stage surgery and were compared with the baseline values. Also, the color match of the graft with the adjacent gingival and mucosal tissues was evaluated.

RESULTS

Forty-seven maxillary implants were evaluated. The minimum and maximum gains of keratinized mucosal width were respectively equal to 0mm and 7mm, with a mean of 4.31±1.19mm. The mean vestibular depth around the implants was 9.47±1.75mm (ranging from 5mm to 12mm) six months after the surgery. At the beginning of the study, a thin mucosa surrounded the implants, but after six months, the peri-implant keratinized mucosa width increased. The color match of the graft with the adjacent gingival and mucosal tissues was excellent based on the periodontists' opinion.

CONCLUSIONS

Modified pedicle grafting is a safe and predictable technique for soft tissue augmentation around maxillary implants. This technique is reliable for increasing the width of keratinized mucosa in fully and partially edentulous patients with a shallow vestibular depth. The stability of the pedicle flap is achieved by fixing the flap to the tissue around the healing abutment.

Intravenous contrast media application using cone-beam computed tomography in a rabbit model

Purpose

This study was performed to evaluate the feasibility of visualizing soft tissue lesions and vascular structures using contrast-enhanced cone-beam computed tomography (CE-CBCT) after the intravenous administration of a contrast medium in an animal model.

Materials and Methods

CBCT was performed on six rabbits after a contrast medium was administered using an injection dose of 2 mL/kg body weight and an injection rate of 1 mL/s via the ear vein or femoral vein under general anesthesia. Artificial soft tissue lesions were created through the transplantation of autologous fatty tissue into the salivary gland. Volume rendering reconstruction, maximum intensity projection, and multiplanar reconstruction images were reconstructed and evaluated in order to visualize soft tissue contrast and vascular structures.

Results

The contrast enhancement of soft tissue was possible using all contrast medium injection parameters. An adequate contrast medium injection parameter for facilitating effective CE-CBCT was a 5-mL injection before exposure combined with a continuous 5-mL injection during scanning. Artificial soft tissue lesions were successfully created in the animals. The CE-CBCT images demonstrated adequate opacification of the soft tissues and vascular structures.

Conclusion

Despite limited soft tissue resolution, the opacification of vascular structures was observed and artificial soft tissue lesions were visualized with sufficient contrast to the surrounding structures. The vascular structures and soft tissue lesions appeared well delineated in the CE-CBCT images, which was probably due to the superior spatial resolution of CE-CBCT compared to other techniques, such as multislice computed tomography.

Effect of tissue composition on dose distribution in electron beam radiotherapy

OBJECTIVE

The aim of this study is to evaluate the effect of tissue composition on dose distribution in electron beam radiotherapy.

METHODS

A Siemens Primus linear accelerator and a phantom were simulated using MCNPX Monte Carlo code. In a homogeneous cylindrical phantom, six types of soft tissue and three types of tissue-equivalent materials were investigated. The tissues included muscle (skeletal), adipose tissue, blood (whole), breast tissue, soft tissue (9-components) and soft tissue (4-component). The tissue-equivalent materials were water, A-150 tissue-equivalent plastic and perspex. Electron dose relative to dose in 9-component soft tissue at various depths on the beam's central axis was determined for 8, 12, and 14 MeV electron energies.

RESULTS

The results of relative electron dose in various materials relative to dose in 9-component soft tissue were reported for 8, 12 and 14 MeV electron beams as tabulated data. While differences were observed between dose distributions in various soft tissues and tissue-equivalent materials, which vary with the composition of material, electron energy and depth in phantom, they can be ignored due to the incorporated uncertainties in Monte Carlo calculations.

CONCLUSION

Based on the calculations performed, differences in dose distributions in various soft tissues and tissue-equivalent materials are not significant. However, due to the difference in composition of various materials, further research in this field with lower uncertainties is recommended.

Tactile Imaging Markers to Characterize Female Pelvic Floor Conditions

The Vaginal Tactile Imager (VTI) records pressure patterns from vaginal walls under an applied tissue deformation and during pelvic floor muscle contractions. The objective of this study is to validate tactile imaging and muscle contraction parameters (markers) sensitive to the female pelvic floor conditions. Twenty-two women with normal and prolapse conditions were examined by a vaginal tactile imaging probe. We identified 9 parameters which were sensitive to prolapse conditions (p < 0.05 for one-way ANOVA and/or p < 0.05 for t-test with correlation factor r from −0.73 to −0.56). The list of parameters includes pressure, pressure gradient and dynamic pressure response during muscle contraction at identified locations. These parameters may be used for biomechanical characterization of female pelvic floor conditions to support an effective management of pelvic floor prolapse.

Injectable tissue-engineered soft tissue for tissue augmentation

Soft tissue augmentation is a process of implanting tissues or materials to treat wrinkles or soft tissue defects in the body. Over the years, various materials have evolved to correct soft tissue defects, including a number of tissues and polymers. Autogenous dermis, autogenous fat, autogenous dermis-fat, allogenic dermis, synthetic implants, and fillers have been widely accepted for soft tissue augmentations. Tissue engineering technology has also been introduced and opened a new venue of opportunities in this field. In particular, a long-lasting filler consisting of hyaluronic acid filler and living human mesenchymal cells called "injectable tissue-engineered soft tissue" has been created and applied clinically, as this strategy has many advantages over conventional methods. Fibroblasts and adipose-derived stromal vascular fraction cells can be clinically used as injectable tissue-engineered soft tissue at present. In this review, information on the soft tissue augmentation method using the injectable tissue-engineered soft tissue is provided.

Penetrating facial injury with an "Airsoft" pellet: a case report

Airsoft is a recreational combat sport that originated in Japan in the 1970s and is currently increasing in popularity in the UK. Participants use air or electrically powered weapons to fire small plastic pellets at a controlled pressure. UK law strictly regulates the maximum muzzle velocity and the type of ammunition used in these weapons. A search of published papers found several reports of penetrating ocular injuries caused by Airsoft pellets, but no reports of penetrating injuries to other areas of the body. We report the case of a 25-year-old man who sustained a penetrating injury to the cheek after being shot with an Airsoft weapon.

Management of treadmill hand injuries using soft tissue distraction

Background:

In the modern day cities, home treadmill usage is increasing. Toddlers are prone to a special injury by the treadmill, during workout the toddler tries to get on the belt and the roller action pulls the fingers under the belt and get caught between the belt and a metal rod under the machine and the belt scrapes the fingers. If untreated some of these injuries will lead to flexion contracture. The usual treatment is release of contracture and skin grafting, however, graft discoloration and recurrence of contracture are the complications of this method and the patients usually seek treatment for the brown discoloration of the grafts at a later age.

Objectives:

In this study we assess the results of Z-plasty in combination with soft tissue distraction without skin grafting with long term usage of splint as an alternative treatment for these patients.

Materials and Methods:

In this retrograde descriptive cross-sectional study, we evaluated the patients presented with treadmill hand injuries between the years 2006 and 2011. Demographic data including age and sex in addition to other information including location of trauma, severity of trauma, time elapsed between the trauma and treatment, type of treatment including wound care and surgical method and treatment outcomes were assessed.

Results:

A total of 8 patients (3 girls and 5 boys) following finger treadmill injury were assessed. 15 fingers in 7 patients had volar injury. The middle finger was the most commonly injured finger. In all patients a minimum of 2 fingers were injured and in just 1 patient 3 fingers were injured. In long-term follow-up all the patients had acceptable volar skin and complete ROM of the fingers.

Conclusions:

Due to discoloration of the skin graft and recurrence of contracture following skin graft as the sole treatment for the injury, application of Z-plasty with soft tissue distraction and long term splints seems to be a proper alternative treatment for these patients.