Cavity Defects Research Articles

The pedicled lateral forehead flap in reconstructing oral floor defect - The last resort; case report.

Introduction and importanceLocoregional flaps, particularly the pedicled lateral forehead flap, are not usually used in reconstructing oral floor defects following oncologic resection. Rather, microscopic free flaps have evolved to be the standard of care in head and neck reconstruction. However, the pedicled lateral forehead flap could be valuable in floor of the mouth reconstruction in the absence of resources or other options.Case presentationA-56 years old lady with multiple comorbidities who underwent near total glossectomy, bilateral supraomohyoid neck dissection, and right lateral mandibulotomy due to a locally advanced lingual squamous carcinoma. The last resort was the pedicled lateral forehead flap after many unsuccessful reconstructive attempts utilizing the free anterolateral flap, free radial forearm flap, and pedicled pectoralis major flap.Clinical discussionDecreased donor site morbidity and reliable anatomy are among many of the advantages that made free flaps favorable over locoregional pedicled flaps, especially in oral cavity defects coverage. Of the latter, the pedicled forehead flap, rich in vascularity and neighboring the oropharyngeal defects, could be used with different techniques and modifications. Close monitoring and patient condition optimization is required.ConclusionChoosing a particular reconstructive option should be done considering the available resources and expertise and the patient's condition. The pedicled forehead flap remains valuable when other options are inappropriate or have failed.

Risk Factors and Complications Associated with Early Oral Intake in Patients Undergoing Microvascular Free Flap Reconstruction of the Oral Cavity: A Single-institution, Retrospective Study

PurposeData on early oral intake (PO) after free flap reconstruction of the oral cavity have been limited. Recent studies have shown that resumption of PO after free flap reconstruction does not lead to increased morbidity and has resulted in decreased hospital stay.1,2 The objective of the study is to assess postoperative complications associated with early PO after free flap reconstruction of the oral cavity and to define clinical predictors for early PO. Materials and methodsA retrospective study was designed and implemented to capture all patients who were treated from 2014 to 2019 at a tertiary hospital and academic medical center. Inclusion criteria included oral cavity defects as a result of malignant or benign disease, trauma, osteoradionecrosis, and medication-related osteonecrosis that required a vascularized free flap reconstruction. Exclusion criteria included unresectable tumors, pharyngeal or laryngeal defects, and facial defects with minimal intraoral involvement (i.e., skin cancer). Clinical and surgical variables were collected and analyzed. The treatment group received PO within 4 days postoperatively. The control group had PO after 4 days postoperatively. The primary outcome was an early complication during the primary hospitalization. Secondary outcomes included late complications and length of stay (LOS). Student's T-test and Chi-square test were used to compare continuous and categorical variables, respectively. In cases where an unequal distribution or a small sample size is present, Mann-Whitney U or Fisher's Exact test was performed. Study variables that were statistically associated with the primary outcome in the bivariate analysis were selected as independent variables for logistic regression analysis. Multivariable logistic regression analysis was used to control for demographic and clinical variables that were statistically significant in the simple logistic regression analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were recorded and interpreted for the regression analysis. For all tests, P values of < .05 were statistically significant. ResultsA total of 457 free flap reconstructions were screened for eligibility. The study sample composed of 423 reconstructions in 164 females and 259 males with the mean age of 59 (range 14-88 years) and mean follow-up duration of 25 months. Sixteen percent of the sample had prior radiotherapy or chemoradiotherapy, and 70% were treated for malignant disease. The majority underwent a tracheostomy (81.6%) and unilateral neck dissection (75.4%). Half had a gastrostomy tube (G-tube) during their hospitalization. The flap success rate was 98%. Patients in the treatment group were less likely to have a tracheostomy, bilateral neck dissection, and g-tube compared to the control group (P < .01) (Table 1). Defect volumes were significantly smaller in the treatment group compared to the control group (P < .01) with buccal and maxillary defects being more common in the treatment group (P < .01). Early PO was associated with decreased LOS (P < .01) and comparable complications (P > .10) in the treatment group compared to the control group (Table 2). Patients in the control group had a higher incidence of neck infection and salivary leak during the primary hospitalization compared to the treatment group. Late complications such as exposed hardware or bone, neck infection, and orocutaneous fistula were more frequent in the control group compared to the treatment group (Table 3). Multivariable regression analysis showed that tracheostomy and defect volume were significant predictors for early PO (P < .01). ConclusionEarly PO after free flap reconstruction of the oral cavity decreases LOS and does not lead to worse outcomes with regards to early and late complications. However, factors such as defect location, defect volume, and tracheostomy may increase the risk for complications and can help guide surgeons in deciding the optimal timing for postoperative PO.

Growth defects of organic crystals: A review

During the growth of organic crystals, crystal defects can be formed. Microscopic defects, which include point, line, and planar defects, appearing as vacancies, growth dislocations, striations, and others, play an important role in the mechanical properties, optical properties, and electrical conductivity of organic crystals. In addition, macroscopic defects, such as fluid inclusions and cavities, may cause toxicity during crystal dehydration and degradation while favorable cavity defects can satisfy certain functions. Herein, this paper summarizes the growth defects of organic crystals from four perspectives; formation mechanism, characterization methods, control methods, and applications. We conclude three kinds of formation mechanism which are related to diffusion of solute molecules, impurities participating in the crystal growth, and structure of solute molecules respectively. Next, the characterization methods are exhibited from the perspectives of microscopy, spectroscopy, and others for different research areas. Then, we offer some control methods of defects which include adjustment of crystallization operation parameters, assistant of ultrasound and additives, irradiation, and ion implantation. As for applications, organic crystal defects have application potential in the fields of pharmacy and materials, for example, nonlinear optical materials, energetic materials, and semiconductor materials. Finally, we put forward the future outlooks on the growth defects of organic crystals.

Fasciocutaneous Type Axial Pattern Local and Regional Flaps: Alternative to Free Flaps?

Emerging usage of carefully harvested, pedicled, local and regional, skin, mucosal, and myomucosal island has a potential to save operating time and resources. Presented here are two such flaps which serves as work horses for moderate defects of the oral cavity, i.e. the islanded nasolabial and facial artery myomucosal flaps, and the technical considerations advocated by the author.

The Influence of Short Chain Branch on the Crystal Characteristics and Breakdown Strength of Low-Density Polyethylene

Studying the influence of short chain branch (SCB) on the crystal properties and breakdown strength of low-density polyethylene (LDPE) plays an important role in improving the electrical and mechanical properties of LDPE by adjusting the molecular structure. In this work, the SCB and long chain branch (LCB) content of LDPE are quantitatively characterized. Grain size, crystallinity and breakdown strength of LDPE (including AC and DC) are calculated through related characterization experiments. The results show that the SCB content in LDPE is dozens of times that of LCB. Reducing the SCB content can reduce the grain size of 110 face in LDPE and improve the AC and DC breakdown strength. The trap distribution characteristics measured by the thermally stimulated depolarization current (TSDC) method show that the SCB inhibits the formation of deep cavity defects in the LDPE interface area and decreases the trap energy level of crystal defects. This inspired us to improve the breakdown strength by reducing the SCB content in LDPE.

Unipedal pectoralis major myocutaneous flap for reconstruction of skin defects in oral cancer surgery: A prospective study of 40 cases

Background: Reconstruction following oral cancer is very important part of the treatment defining both aesthetic and functional aspects. Options available for reconstructions are regional pedicle flaps and microvascular free flaps. Pectoralis major myocutaneous (PMMC) flap is regarded as the workhorse for reconstruction in the area of oral cavity and neck. A unipedicle PMMC is a good option for reconstruction of full thickness defects after resection of tumors of oral cavity. Material and Methods: A study was undertaken on patients of soft tissue defects of head and neck region after resection of tumor of oral cavity (squamous cell carcinoma). Total 40 patients, who were treated in the department of surgical oncology were included in this study. Results: Gingivo-buccal complex was the most common site observed for oral malignancy and majority of patients were in TNM stage- III in this study. Flap survival was good in majority of cases excluding one case of total flap necrosis and 5 cases of minor edge necrosis. Conclusions: Unipedal PMMC flap is effective in reconstruction of full thickness defect of oral cavity defects even in the era of free flap reconstructions especially in developing countries. Despite few minor flap related complications PMMC flap survival rate is high and total flap necrosis rate is uncommon.

Dynamic anti-plane behavior of rare earth giant magnetostrictive medium with a circular cavity defect in semi-space

An analytical solution to the anti-plane dynamics problem of semi-space rare earth giant magnetostrictive media with circular cavity defects near the horizontal boundary under the action of SH wave is studied. Based on the Helmholtz theorem and the theory of complex function, the elastic-magnetic dynamic equation of magnetostrictive medium is established, and the semi-space incident wave field is written. In addition, based on the theory of complex function and the method of wave function expansion, the expression of the wave function of the scattered displacement field and the corresponding magnetic potential of the scattered wave under the condition of no stress and magnetic insulation of the horizontal boundary are obtained. Then, based on the conditions of free boundary stress, continuous magnetic induction intensity and continuous magnetic potential around the circular cavity, the infinite linear algebraic equations are established. Finally, the analytical expressions of dynamic stress concentration factor and magnetic field intensity concentration factor around circular cavity in semi-space rare earth giant magnetostrictive medium are obtained. Numerical examples show that the analysis results depend on the following parameters: permeability, dimensional-piezomagnetic coefficient, frequency of the incident wave, incident angle, distance between the circular cavity and horizontal boundary. These results have certain reference value for the study of non-destructive testing and failure analysis of rare earth giant magnetostrictive materials.

Vein preservation strategies to improve the survival rate of the infrahyoid musculocutaneous flap.

The infrahyoid musculocutaneous flap (IHMCF) is a good alternative in the reconstruction of moderate‐sized oral cavity surgical defects. Insufficient venous drainage can significantly affect the survival rate of this flap.ObjectivesIdentify the survival rates of the IHMCF and evaluate the functional capacity of reconstructed patients.DesignWe report a case series.SettingThis study took place at the Department of Head and Neck Surgery of Oncology Hospital Ho Chi Minh City, the largest oncology center in South Vietnam.ParticipantsOne hundred and twelve patients with surgical defects after oral cavity resection for cancer underwent IHMCF reconstruction from November 2013 to November 2018. During the harvest of the flap, our modification of the surgical technique specifically attempted to preserve more secondary veins for IHMCF.Main Outcome MeasuresPostoperative viability of the flap was checked by clinical observation. The last examination was performed at 3‐months after reconstructive operation or after the completion of adjuvant radiotherapy. The functional capacity of our patients was evaluated by three physicians (Head and Neck Surgeon, Radiation Oncologist, and Physiatrist) with understandability of speech scale and the functional oral intake score items assessed.ResultsTwo cases of partial skin necrosis (1.8%) were experienced. The majority of patients demonstrated favorable functional rehabilitation at long‐term follow up.ConclusionsThe IHMCF is a reliable flap suitable for moderate‐sized defects of the oral cavity. Altering the surgical approach to specifically preserve more venous outflow can improve the survival rate of the flap.Level of Evidence4.

Technical Considerations and Outcome Analysis of Using Extended Bipaddle Pectoralis Major Myocutaneous Flaps for Reconstructions of Large and Complex Oral Cavity Defects: Expanding the Horizons.

The online version contains supplementary material available at 10.1007/s13193-021-01345-1.

Novel modification of infrahyoid myocutaneous flap for the reconstruction of oral cavity defects

This study was intended to describe the technique used and the results obtained with the modification of the infrahyoid flap (IHF) for the reconstruction of oral tongue defects following resection for advanced squamous cell carcinoma (SCC). Patients with oral tongue defects following ablation for T2 to T4a SCC had reconstructions using a modified infrahyoid flap. Demographic data, tumour characteristics, and the complications were evaluated for each patient. We observed no complications regarding the healing process of the donor site or success of the flap in 49 (of 55) patients. None of the flaps had massive oedema or venous congestion in the postoperative period. Six patients experienced flap-related complications of which five had partial skin paddle necrosis, but eventually their flaps recovered and re-epithelialised without any further intervention. However, total flap necrosis was seen in one patient in whom a pectoralis major flap was used for the defect reconstruction following revision surgery. History of previous radiotherapy to the neck (p = 0.003), tumour stage (p = 0.017), and metastasis to cervical lymph nodes (p = 0.004) were associated with higher prevalence of partial or total flap necrosis. The modified infrahyoid flap is a reliable, quick, and simple procedure with a reasonable cost that makes it a valuable option for the reconstruction of the oropharynx and oral cavity with minimal donor site morbidity and good outcomes. It seems the modified IHF is a valid surgical procedure that may be considered in selected patients undergoing reconstruction of oncological oral tongue defects with fewer complications.

The submental flap – Outcomes and oncologic safety in head and neck reconstruction

IntroductionThe submental flap is a reliable alternative to free flaps in the reconstruction of cutaneous facial and oral cavity defects. The thin, pliable, easily harvested flap has minimal donor site morbidity. The flap is controversial due to the potential involvement of level I lymph nodes within the flap. We describe 40 cases of head and neck reconstruction with the submental flap following resection of various cancers, and assess the oncologic safety of this flap at our centre. AimsTo evaluate the outcomes of the submental flap and assess the oncologic safety of the flap on follow-up. Material and methodsPre-operative, post-operative and follow-up data of 40 consecutive patients with oral cavity and parotid malignancies, who underwent reconstruction with the submental flap between January 2017 and June 2019, was analysed. ResultsOral cavity defects following resection of carcinoma tongue were predominant (n = 19). Patients were considered suitable for reconstruction with the submental flap only when level Ia and Ib nodes were clinically and radiologically negative for metastasis. Neck dissection was performed in all cases, with careful dissection of all level Ib nodes along the submental perforators. Flap complications were minimal. During a mean follow-up period of 14 months, no recurrences were noted within the flap. ConclusionsThe submental flap, although not the first choice, is a reliable alternative to free flaps in the reconstruction of oral defects. However, selection of patients with clinically node negative disease is extremely important, due to the potential risk of occult metastasis.

High quality factor, protein-based microlasers from self-assembled microcracks

In the last decade, microlasers with biological origin have shown their great potential in biosensing and bioimaging. Several micro-structures have been developed for high quality (Q) factor biolasers including Fabry–Pérot, distributed feedback and whispering gallery mode cavities. However, the fabrication of these lasers is generally complicated and their operation is strongly affected by cavity defects. In this work, we demonstrate random protein-based microlasers fabricated by a simple one-step self-assembled method. The lasing can be achieved from microcracks with random structures. The lasing threshold is around 14 mJ cm−2 and the quality factor of lasing modes can be up to which are comparable with other conventional biolasers. Our work opens a new possibility for the fabrication of high Q factor microlasers from biocompatible materials, with great potential for biosensing and biomedical applications.

The surgical management of the cavity and bone defects in enchondroma cases: A prospective randomized trial

BackgroundWe compared the curettage/bone grafting and the curettage/bone graft substitutes surgical techniques in their relation to functional outcomes, oncologic outcome (recurrence, malignant transformation), the rate of postsurgical complications, durations of surgery and of postsurgical immobilization for hand-localized cases of solitary and multiple enchondromas. MethodsThe current prospective randomized trial analyzed 200 adult patients (2012–2017) with enchondroma who underwent surgical intervention. The cases were randomly divided into Group 1 (n = 100; F 56, M 44) for surgeries with curettage and autogenous bone grafting, and Group 2 (n = 100; F 55, M 45) for surgeries with curettage and bone graft substitutes. The placebo control Group 3 consisted of cases operated by curettage only (n = 56; F 31, M 25). The follow-up period was set at 30 months. ResultsThe duration of surgery was 51 ± 4 min in Group 1 and 27 ± 1 min in Group 2 (p = 0.008). In Group 1, the rate of recurrence was 6% against 1% in Group 2 (p = 0.005). No other statistically significant differences in postsurgical outcomes between three involved groups were noted. ConclusionIn cases of enchondroma of the hand, postsurgical functional outcomes, the rate of postsurgical complications, the duration of immobilization, and the time to complete recovery are not influenced by the type of chosen grafting material. The implementation of HAp-collagen bone substitutes in granules instead of autogenous bone grafting reduces the duration of surgery. The implementation of autogenous bone grafting may increase the rate of tumor recurrence.

Changes in the Parameters of the Electromagnetic Response of Model Dielectric Samples with Air Cavity Defects under External Deterministic Acoustic Impact

The paper discusses the possibility of testing the air inclusions saturation in cement-sand samples using the acoustic-electrical transformations phenomenon in heterogeneous dielectric materials. An experiment technique is presented including contact external acoustic excitation and contactless registration of the electromagnetic response to such an impact. Methods of samples deterministic acoustic excitation by a ball impact and the experimental determination of the impact energy are described. The model samples size and composition are described, including air cavities in a polyethylene sheath. The experimental studies geometry is shown, indicating the direction of the samples acoustic excitation and the location of the electromagnetic receiving plates. It is shown that the defect-free samples and with air cavities, have different amplitude and frequency of the electromagnetic signals spectral components. The samples with air cavities have the average weight of the EMS spectrum changes towards lower frequencies. This frequency shift effectively reflects the concentration of air cavities defects in a cement-sand samples and this effect can be used when testing concrete products for the presence of air inclusions, and, accordingly, will allow determining the frost resistance of products.

Single Free Flap for Large Defects in Head and Neck Reconstruction, Double Paddle Anterolateral Thigh Flap

Abstract The purpose of the study is to evaluate the efficacy of double skin paddle anterolateral thigh flap (ALT) to reconstruction of through and through oral cavity defect due to cancer surgery. A prospective review was performed of patients referred to Firoozgar and Erfan hospitals with oral cavity defects with two or more oral cavity subunits and skin simultaneously involvement and immediate reconstruction using double-skin paddle ALT flap at the same time of tumor ablation from January 2019 to November 2020. A total number of 6 patients was evaluated. The mean area of skin paddle was 110.4 cm2 and 92.8 cm2 in distal and proximal paddle respectively. Except one patient was complicated and expired in hospital admission, the remaining 5 patients got fully oral intake and completely survived flaps with primarily closed donor site. Tumor recurrence was not found in the mean follow-up time of 12 months. The double skin paddle anterolateral thigh flap serves as an efficient reconstruction technique in complex and perforating oral cavity defects with the same functional outcome and the same flap related complications as conventional ALT flap.

Nov model zapiranja votlin in razvoj novih pod vplivom različnih napetostnih stanj

Cavity defects including a shrinkage cavity, air hole and porosity are typical defects of an ingot, which are difficult to avoid. These defects can disappear during deformation at a reasonably high temperature and heat-preservation process so as to ensure the quality of forgings. However, the current understanding of the mechanism of the void closure is insufficient, and the models that can accurately predict the evolution of a void are relatively rare. Based on the representative-volume-element model, a theoretical analysis and numerical simulation, the influence of the Lode parameter and stress triaxiality on the void closure is expounded. Besides, based on the above research, a new void-evolution model considering all kinds of macro-stress states is proposed. The model can predict the closure degree of voids in different positions and various macro-stress states during the plastic deformation of ingots. Comparing the new void-evolution model with other models, numerical simulations and physical-simulation results, the accuracy of the proposed void-evolution model is verified.

Stress field and damage evolution in C/SiC woven composites: Image-based finite element analysis and in situ X-ray computed tomography tests

The construction and examination of meso-structural finite element models of a Chemical-Vapor-Infiltrated (CVI) C/SiC composite is carried out based on X-ray microtomography digital images (IB-FEM). The accurate meso-structural features of the C/SiC composites, which are consisted of carbon fiber tows and CVI-SiC matrix, in particular the cavity defects, are reconstructed. With the IB-FEM, the damage evolution and fracture behaviors of the C/SiC composite are investigated. At the same time, an in situ tensile test is applied to the C/SiC composite under a CT real-time quantitative imaging system, aiming to investigate the damage and failure features of the material as well as to verify the IB-FEM. The IB-FEM results indicate that material damage initially occur at the defects, followed by propagating toward the fiber-tow/SiC-matrix interfaces, ultimately, combined into macro-cracks, which is in good agreement with the in situ CT experiment results.

Free Gastric Flap for Oral Reconstruction-a Feasibility Study in Oral Defects.

Free flap transfer is a standard practice in reconstruction of oral defects. Fasciocutaneous flaps are commonly used for reconstruction of soft tissue defects. Replacement of oral mucosa with skin often causes discomfort, foreign body sensation, dysgeusia, problems with skin hair and morbidity at the donor site. Morbidity at the donor site may interfere with physical activity among manual labourers. We prospectively analysed nine cases of oral cavity defects reconstructed with free gastro-omental flap over 4 months from March to July 2019. A free gastric flap based on right and left gastric artery and vascular arcade was harvested from the body of stomach. Feasibility, technical aspects, advantages and disadvantages of the flap are reviewed. Flap survival was 100%. No re-exploration for salvage was required. Flap was monitored for viability by colour change and capillary refill. All the nine cases healed well. One patient required readmission for bleeding from the raw area exposed at the margins of the flap. Patient satisfaction and quality of life was satisfactory. Long pedicle length, rich submucosal vascular network, dual pedicles available for anastomosis, like to like mucosal tissue replacement and low donor site morbidity make it a reliable option in the armamentarium of oral reconstruction. Free gastro-omental flap is a feasible and reliable tissue available for reconstruction of oral soft tissue defects.

Reconstruction of medium-size defects of the oral cavity: radial forearm free flap vs facial artery musculo-mucosal flap

BackgroundThe radial forearm free flap (RFFF) is the most commonly used flap for defects of the oral cavity. The facial artery musculomucosal (FAMM) is a safe and effective method to reconstruct medium sized defects of the oral cavity. No comparison exists between the FAMM flap and RFFF.Methods1) Retrospective chart review from 2007 to 2016. 2) Cost difference analysis.ResultsThirteen FAMM flap cases and 18 RFFF met inclusion criteria. The FAMM flap showed a tendency to lower rates of return to the operating room (p = 0.065) as well as lower rates of complications not requiring return to the OR with 1 complication in 1 patient as opposed to 10 patients with 15 complications (p = 0.008). Also, FAMM flap had shorter operative times compared to the RFFF group (7.2HR and 8.9 HR respectively, p = 0.002). The average operative room related costs for a FAMM flap were 6510 CAD vs 10,703 CAD for RFFF (p < 0.0005). Speech and swallowing outcomes were similar (p > 0.05).ConclusionThe FAMM flap can be used for reconstruction of medium-size defects of the oral cavity with functional outcomes similar to the RFFF while decreasing the associated costs and morbidity.Graphical

Порівняльна характеристика динамічних жувальних проб

Summary. Chewing is one of the important functions of a person that ensures vital functions. Many works have been devoted to the definition of chewing efficiency for almost a hundred years. However, most of them are not currently used, which is due to the complexity and complexity of the implementation. This review is devoted to the coverage and comparison of dynamic masticatory samples to select the optimal for use in patients in the postoperative period with defects of the oral cavity and oropharynx. Key words: chewing efficiency, dynamic test, oral cavity defects.