Intrauterine adhesion.

Intrauterine adhesions (IUA) occurred in the reproductive-age women are a big economic and health problem, resulting in severe impairment of social, psychological and physical function of the female genital organs. IUA-related symptoms or signs are varied greatly from free of symptoms or ambiguous symptoms (an incidental finding during the intervention) to ceased menstruation and loss of fecundability. The underlying pathophysiology is not completely understood, but intrauterine damage with broken basal layers of the endometrium formatting scar tissues or fibrosis in the endometrium with subsequently causing partial or complete occlusion of the uterine cavity may be a well-accepted hypothesis. Previously, infection is the most common cause to develop IUA, but now, intrauterine surgery may be a critical cause contributing to the majority of cases of IUA. In the current review, update information about the etiology, epidemiology, pathophysiology, sequelae and prevention of IUA will be renewed. We emphasize the importance of awareness of IUA, and primary prevention should be considered in the routine clinical practice if intrauterine surgery has been applied, based on uncertainty of ideal treatment for the established IUA and unpredictable outcomes after IUA treatment. So far, evidence supports that hyaluronic acid with/without other strategy is the most valuable and effective method to reduce the formation and re-formation of IUA as well as to achieve the best fertility outcome.

Sterilized human skin graft with a dose of 25 kGy provides a privileged immune and collagen microenvironment in the adhesion of Nude mice wounds.

This study aimed to report the effects of different doses of ionizing radiation on inflammatory and repair stage of human skin graft adherence in Nude mice wounds. Animals were divided into transplanted with irradiated human skin grafts (IHSG) at 25 and 50 kGy (IHSG 25 kGy; IHSG 50 kGy) and non-IHSG and euthanized on the 3rd, 7th and 21st days after the surgery, by gross and microscopic changes, immunostaining for human type I collagen (Col I) and mouse Col I and Col III and inflammatory cells. We found an effectiveness of human split-thickness graft adherence in mice transplanted with IHSG 25 kGy, as well decrease in dermo-epidermal necrosis and neutrophils, lower loss of skin thickness, epithelization and neo-vascularization. Day 21 post-transplantation with IHSG 25 kGy was observed a well-preserved human skin in the border of the graft, a prominent granulation tissue in an organization by proliferated fibroblasts, Col III deposition and increased B-cells and macrophages. A complete adherence of human skin graft occurred with IHSG 25 kGy. We suggest that the ionizing radiation at 25 kGy mediates inflammation and the repair stage of human skin graft adherence in murine model, thus emerging as a potential tool in healing cutaneous wounds.

Management of intrauterine adhesions using human amniotic mesenchymal stromal cells to promote endometrial regeneration and repair through Notch signalling.

Intrauterine adhesions (IUAs) severely hamper women's reproductive functions. Human amniotic mesenchymal stromal cell (hAMSC) transplantation is effective in treating IUAs. Here, we examined the function of Notch signalling in IUA treatment with hAMSC transplantation. Forty-five Sprague-Dawley female rats were randomly divided into the sham operation, IUA, IUA + E2, IUA + hAMSCs and IUA + hAMSCs + E2 groups. After IUA induction in the rats, hAMSCs promoted endometrial regeneration and repair via differentiation into endometrial epithelial cells. In all groups, the expression of key proteins in Notch signalling was detected in the uterus by immunohistochemistry. The results indicated Notch signalling activation in the hAMSCs and hAMSCs + E2 groups. We could also induce hAMSC differentiation to generate endometrial epithelial cells in vitro. Furthermore, the inhibition of Notch signalling using the AdR-dnNotch1 vector suppressed hAMSC differentiation (assessed by epithelial and mesenchymal marker levels), whereas its activation using the AdR-Jagged1 vector increased differentiation. The above findings indicate Notch signalling mediates the differentiation of hAMSCs into endometrial epithelial cells, thus promoting endometrial regeneration and repair; Notch signalling could have an important function in IUA treatment.

The impact of nasal adhesions on airflow and mucosal cooling - A computational fluid dynamics analysis.

Nasal adhesions are a known postoperative complication following surgical procedures for nasal airway obstruction (NAO); and are a common cause of surgical failure, with patients often reporting significant NAO, despite relatively minor adhesion size. Division of such nasal adhesions often provides much greater relief than anticipated, based on the minimal reduction in cross-sectional area associated with the adhesion. The available literature regarding nasal adhesions provides little evidence examining their quantitative and qualitative effects on nasal airflow using objective measures. This study examined the impact of nasal adhesions at various anatomical sites on nasal airflow and mucosal cooling using computational fluid dynamics (CFD). A high-resolution CT scan of the paranasal sinuses of a 25-year-old, healthy female patient was segmented to create a three-dimensional nasal airway model. Virtual nasal adhesions of 2.5 mm diameter were added to various locations within the nasal cavity, representing common sites seen following NAO surgery. A series of models with single adhesions were created. CFD analysis was performed on each model and compared with a baseline no-adhesion model, comparing airflow and heat and mass transfer. The nasal adhesions resulted in no significant change in bulk airflow patterns through the nasal cavity. However, significant changes were observed in local airflow and mucosal cooling around and immediately downstream to the nasal adhesions. These were most evident with anterior nasal adhesions at the internal valve and anterior inferior turbinate. Postoperative nasal adhesions create local airflow disruption, resulting in reduced local mucosal cooling on critical surfaces, explaining the exaggerated perception of nasal obstruction. In particular, anteriorly located adhesions created greater disruption to local airflow and mucosal cooling, explaining their associated greater subjective sensation of obstruction.

Wrist Contracture Caused by Adhesion of the Extensor Carpi Radialis Tendon after Distal Radius Fracture: A Case Report.

Although distal radius fractures are common, wrist contracture caused by an extra-articular lesion after a distal radius fracture is seldom reported. We report a rare case of wrist contracture caused by adhesion of extensor carpi radialis brevis (ECRB) tendon after distal radius fracture. The patient was successfully treated with tenolysis of the ECRB tendon.

SURGICAL OUTCOMES OF VITREOMACULAR TRACTION TREATED WITH FOVEAL-SPARING PEELING OF THE INTERNAL LIMITING MEMBRANE.

PURPOSE: To compare sensitivity of the retina after complete internal limiting membrane (ILM) peeling versus foveal-sparing ILM peeling in vitrectomy for vitreomacular traction syndrome. METHODS: This was a randomized, prospective, comparative study. Thirty-four eyes were randomized to undergo peeling with foveal sparing of the ILM (FS group) or complete peeling group. Foveal and perifoveal retinal sensitivity, visual acuity, and central macular thickness were the main outcome measures. RESULTS: Parafoveal retinal sensitivity exhibited a significant improvement in both the FS and complete peeling groups (+2.43 ± 0.82 dB and +1.79 ± 0.86 dB, respectively; P = 0.037). Significant improvements were observed in both visual acuity and central macular thickness in both groups. No cases of epiretinal membrane recurrence were observed in the FS group. CONCLUSION: Both the FS and complete peeling surgical techniques are safe and yielded good anatomical and functional results; however, a significant difference in favor of FS was found in relation to the best-corrected visual acuity and perifoveal retinal sensitivity. Preservation of the foveal ILM disc allowed the anatomical restoration of the foveal architecture in most vitreomacular traction syndrome cases without signs of stiffening or ILM fibrosis over a follow-up period of 1 year.

Transplantation of Human Amnion Epithelial Cells Improves Endometrial Regeneration in Rat Model of Intrauterine Adhesions.

Intrauterine adhesions (IUAs) are characterized by the injury of endometrium due to curettage and/or endometritis. The loss of functional endometrium in uterine cavity usually results in hypomenorrhea, amenorrhea, infertility, and/or recurrent pregnancy loss. Recently, stem cell transplantation has been applied to promote the endometrial regeneration. Human amnion epithelial cells (hAECs) have been shown to have stem cell characteristics. In this study, we found that PKH26-labeled hAECs were mainly distributed in the basal layer of endometrium after transplantation, and hAEC transplantation, including uterine injection and tail vein injection, could increase pregnancy rate and the number of embryos in rat model of IUAs. Moreover, hAEC transplantation was demonstrated to increase the endometrial thickness, promote the proliferation of glands and blood vessels, and decrease fibrotic areas in the endometrium. The immunohistochemical and quantitative polymerase chain reaction analysis showed the upregulated expression of growth factors, such as basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1) after hAEC transplantation; and the downregulated expression of collagen type I alpha 1 (COL1A1), tissue inhibitor of metalloproteinase-1 (TIMP-1), and transforming growth factor-ß (TGF-ß), all of which are associated with the extracellular matrix (ECM) deposition after hAEC transplantation. The mRNA sequencing indicated that platelet-derived growth factor-C (PDGF-C), thrombospondin-1 (THBS1), connective tissue growth factor (CTGF), Wnt5a, and Snai2 were significantly modulated in treatment groups. These results indicate that hAEC transplantation promotes endometrial regeneration and the restoration of fertility in rat model of IUAs.

Fu's subcutaneous needling for subcutaneous adhesions and scar hyperplasia in the neck region: A case report.

RATIONALE: Lymphadenectomy for tongue cancer in the neck region is often accompanied by local impaired mobility, gland damage, difficult in swallowing, and postoperative complication and seriously affects patients life quality. We reported a case of subcutaneous adhesions and scar hyperplasia in the neck region after lymphadenectomy for tongue lesions accompanied by impaired neck mobility and difficult in swallowing was treated using Fu's subcutaneous needling (FSN) treatment. PATIENT CONCERNS: A 55-year-old male with tongue cancer received surgical intervention with lymphadenectomy 8 years ago was revealed a 15 cm-long curved surgical incision in the neck region and surrounded by numerous scar tissues. DIAGNOSIS: Post-operation subcutaneous adhesions and scar hyperplasia in the neck region after lymphadenectomy was diagnosed. INTERVENTIONS: FSN treatment was performed 2 to 3 times per week for 1 month to sway the affected tightened muscle and dissociate the superficial fascia beneath the scar resulted in a considerable improvement in neck movement. OUTCOMES: The Vancouver Scar Scale (VSS) was as follows: color (M) - 1; vascular distribution (V) - 0, thickness (H) - 2, and flexibility (P) - 4, with a total of 7 points before FSN treatment. The VSS after 1 month of FSN treatment was as follows: M1, V0, H2, and P2, with a total of 5 points. Neck mobility in different directions, i.e., stretching to the back of the neck and laterally bending the neck to the left and/or right side, was improved (P < .05). LESSONS: At present, treatment of chronic scar hyperplasia has certain side effects and limitations. FSN is safe and convenient, with minimal destruction of the superficial fascia, having evident effects of dissociating tissue adhesion under scars and compensating for deficiencies in scar hyperplasia treatment. It can provide new ideas for future treatments.

Craniopharyngioma treatment: an updated summary of important clinicopathological concepts.

INTRODUCTION: Craniopharyngiomas (CPs) are benign histological tumors that may develop at different positions along the hypothalamic-pituitary axis. Their close, heterogenous relationship to the hypothalamus makes surgical removal challenging even though this remains the primary treatment strategy. AREAS COVERED: This article presents a critical overview of the pathological and clinical concepts regarding CPs that should be considered when planning treatment. Thus, we have performed a comprehensive review of detailed CP reports published between 1839 and 2020. EXPERT OPINION: CP surgery should pursue maximal tumor resection while minimizing the risk of injuring the hypothalamus. Therefore, surgical strategies should be individualized for each patient. Accurate assessment of presenting symptoms and preoperative MRI has proven useful to predict the type of CP-hypothalamus relationship that will be found during surgery. CPs with dense and extensive adhesions to the hypothalamus should be highly suspected when MRI shows the hypothalamus positioned around the mid-third of the tumor and an amputated upper portion of the pituitary stalk. Symptoms related to functional impairment of the infundibulo-tuberal area of the third ventricle floor, such as obesity/hyperphagia, Fröhlich's syndrome, diabetes insipidus, and/or somnolence, also indicate risky CP-hypothalamic adhesions. In these cases, limited tumor removal is strongly advocated followed by radiation therapy.

[Adhesion problems of stoma accessories due to peristomal dermatitis]. / Slecht hechtende stomaplak door dermatitis.

Peristomal dermatitis is a frequent problem in stoma patients. This causes problems with the adhesion of stoma material. Not being able to rely on a leak-free stoma plaque has major social consequences for stoma patients. In this article we discuss the differential diagnosis, pathophysiology and therapy based on a patients case. If the dermatitis is based on an irritating contact dermatitis due to the stoma adhesive, the dermatitis should be treated with a local corticosteroid, preferably in the form of a nasal spray.

Contrast Dispersion on Epidurography May Be Associated with Clinical Outcomes After Percutaneous Epidural Neuroplasty Using an Inflatable Balloon Catheter.

BACKGROUND: Contrast dispersion pattern on epidurography may be associated with clinical improvement after epidural neuroplasty. However, insufficient evidence supports this theory. The current study aims to evaluate the relevance of contrast dispersion and clinical improvement after percutaneous epidural neuroplasty using an inflatable balloon catheter. METHODS: One hundred patients with lumbar spinal stenosis who underwent combined balloon decompression and epidural adhesiolysis between March 2015 to December 2015 participated in the present study. Participants were divided into two groups by contrast dispersion pattern on postprocedural epidurography: the complete contrast dispersion (CCD) and incomplete contrast dispersion (ICCD) groups. The numeric rating scale (NRS), Oswestry Disability Index (ODI), and global perceived effects (GPE) were each assessed before and one, three, six, nine, and 12 months after the intervention. RESULTS: After combined balloon decompression and adhesiolysis, significant pain reduction and functional improvement were maintained up to 12 months in patients with lumbar spinal stenosis. NRS and GPE in the CCD group were significantly lower than in the ICCD group from six to 12 months after the intervention. The ODI in the CCD group was also significantly lower compared with that in the ICCD group from one to 12 months after the intervention. CONCLUSIONS: Combined balloon decompression and adhesiolysis with the inflatable balloon catheter can provide noteworthy pain reduction and improvement of physical function for a long-term period in patients with lumbar spinal stenosis. Because CCD showed better clinical improvement compared with ICCD, a contrast dispersion pattern may be associated with an improved clinical outcome.

Using cross-linked hyaluronic acid gel to prevent postoperative lumbar epidural space adhesion: in vitro and in vivo studies.

PURPOSE: Hyaluronic acid prevents tissue adhesion after different surgeries. Physical barriers and inflammatory regulation have been suggested to be involved in the mechanism of these clinical effects. However, the molecular mechanism by which hyaluronic acid prevents epidural adhesion has not yet been reported. METHODS: In the current in vivo studies, we investigated cross-linked hyaluronic acid gel in the regulation of scar gene expression, the accumulation of fibroblasts in scar tissue, and the prevention of epidural adhesion. The effect of cross-linked hyaluronic acid gel on the secretion of inflammatory factors was observed in vitro. In addition, to ensure the accuracy and reliability of the in vivo gene expression results, we used a cell model to detect the target genes in vitro. RESULTS: The expression levels of TGFß1 and COL1A1 mRNA were decreased in the cross-linked hyaluronic acid gel-treated group, and the protein expression of levels TGFß1 and COL1A1 were also reduced, as detected by Western blotting in vitro and in vivo (P < 0.05). Histomorphometry results demonstrated that the number of fibroblasts in the experimental group was significantly lower than that in the control group 2 weeks postoperatively. Micro-CT scans showed that the cross-linked hyaluronic acid gel could reduce adhesion in the epidural space after laminectomy. Additionally, the cross-linked hyaluronic acid gel could inhibit IL-6 secretion. CONCLUSIONS: These results indicate that cross-linked hyaluronic acid gel can prevent epidural adhesion by inhibiting inflammatory factors, such as IL-6, and downregulating TGFß1 and COL1A1 mRNA expression. These slides can be retrieved under Electronic Supplementary Material.

NPPB prevents postoperative peritoneal adhesion formation by blocking volume-activated Cl- current.

5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) is a non-specific chloride channel blocker. Peritoneal adhesion is an inevitable complication of abdominal surgery and remains an important clinical problem, leading to chronic pain, intestinal obstruction, and female infertility. The aim of this study is to observe the effects of NPPB on peritoneal adhesions and uncover the underlying mechanism. The formation of postoperative peritoneal adhesions was induced by mechanical injury to the peritoneum of rats. MTT assay and wound-healing assay were used to evaluate proliferation and migration of primary cultured adhesion fibroblasts (AFB) respectively. Whole-cell chloride currents were measured using a fully automated patch-clamp workstation. Cell volume changes were monitored by light microscopy and video imaging. Our results demonstrated that NPPB could significantly prevent the formation of peritoneal adhesion in rats and inhibit the proliferation of AFB in a concentration-dependent manner. NPPB also reduced the migration of AFB cells with an IC50 of 53.09 µM. A 47% hypotonic solution successfully activated the ICl,vol in AFB cells. The current could be blocked by extracellular treatment with NPPB. Moreover, 100 µM NPPB almost completely eliminated the capacity of regulatory volume decrease (RVD) in these cells. These data indicate that NPPB could prevent the formation of postoperative peritoneal adhesions. The possible mechanism may be through the inhibition of the proliferation and migration of AFB cells by modulating ICl,vol and cell volume. These results suggest a potential clinical use of NPPB for preventing the formation of peritoneal adhesions.

Urinary bladder matrix scaffolds improve endometrial regeneration in a rat model of intrauterine adhesions.

Intrauterine adhesions caused by damage to the basal layer of the endometrium have a serious impact on women's fertility. Currently, there is no effective treatment to promote the regeneration of the endometrium. Urinary bladder matrix (UBM) is a derivative extracellular matrix biomaterial that has a complete basement membrane and provides a basis for the body to achieve complete self-functional repair. In this study, UBM was transplanted into the uterine horns of intrauterine adhesions in Sprague-Dawley rats to test whether UBM could improve endometrial regeneration in rats with intrauterine adhesions. Thicker endometria, increased numbers of glands, fewer fibrotic areas and increased proliferation of cells and blood vessels were found in the UBM group compared to the injury group. Transplantation of UBM reduced the mRNA levels of proinflammatory cytokines (tumor necrosis factor α) and increased those of anti-inflammatory cytokines (basic fibroblast growth factor) compared to the injury group. In the UBM group, the mRNA expression of endometrial receptivity factors (leukemia inhibitory factor and integrin αVß3) was higher than that in the injury group, but it was lower than that in the normal group and the sham-operated group. More embryos were seen in the UBM group than in the injury group, although the UBM group had fewer embryos than the normal and sham-operated groups. Therefore, UBM may contribute to endometrial regeneration and may improve endometrial receptivity and fertility.

A comparison in an experimental rat model of the effects on adhesion formation of different hemostatic methods used in abdominopelvic surgery.

OBJECTIVES: To evaluate the effects of different hemostasis methods used in abdominal surgery on the development ofabdominal adhesion. MATERIAL AND METHODS: A total of 48 Wistar albino female rats were separated into six groups; Group 1 - Control group,Group 2 - Hemorrhage group, Group 3 - Electrocoautery group, Group 4 - Gel Spon-P®, Group 5 - PAHACEL®, andGroup 6 - Ankaferd-Blood Stopper®. Adhesions that developed were scored according to the Knightly classification andthe prevalence of adhesions according to the Linsky classification. The total adhesion score was calculated as the total ofthe severity and prevalence scores. RESULTS: The lowest total adhesion values were determined in Group 1 (control) and the highest adhesion values were inGroup 2 (hemorrhage) group in terms of all parameters. The adhesion values in Group 3, where the rats were administeredhemostasis with electrocautery were similar to those of Group 2 (hemorrhage). When the alternative methods were evaluated,the lowest adhesion scores were in Group 6 (Ankaferd-Blood Stopper®). CONCLUSIONS: In cases of minor pelvic or abdominal bleeding, not providing hemostasis or applying hemostasis withelectrocautery can increase the development of intra-abdominal adhesions. The use of alternative hemostatic materialsinstead of electrocautery for hemostasis may reduce the formation of adhesions.

Preoperative Detection of Pleural Adhesions Using Ultrasonography for Ipsilateral Secondary Thoracic Surgery Patients.

BACKGROUND/AIM: Video-assisted thoracic surgery (VATS) for ipsilateral reoperations is challenging because of the potential for pleural adhesions. Insertion of the initial port can lead to lung injury because of the blinded intrathoracic area. We assessed the usefulness of ultrasonography before VATS to reduce the incidence of lung injury at the time of the initial port insertion during secondary ipsilateral VATS. PATIENTS AND METHODS: Thirty-three patients who underwent repeat VATS for ipsilateral pulmonary lesions were included. All patients underwent preoperative ultrasonography to assess the possible presence of pleural adhesions using the lung sliding sign. RESULTS: Seven adhesions were found at the VATS ports. Two of these adhesions were not evaluated as pleural adhesions using ultrasonography; however, they were loose. All initial ports were inserted without lung injury. There were no major complications. CONCLUSION: Preoperative detection of pleural adhesions using ultrasonography can determine the best initial port for secondary ipsilateral VATS.

Investigations on the adhesion of new composites for restoring cervical lesions using energy dispersive X-ray analysis and scanning electron microscopy.

Restoration of noncarious cervical lesions with resin composites is one of the treatment options, but the retention of the restorations located at the crown-root junction is still a cause of clinical concern. The aim of this study was to evaluate the adhesive properties of three experimental resin composites and two commercial materials used to restore cavities prepared on extracted teeth as well as to determine the relative elemental composition of these materials. We tested the null hypothesis, which considered that the adhesive behaviours of different resin composites did not differ. The microleakage test using tracers showed that all tested materials exhibited some degree of dentinal microleakage, although they all had good dentinal adhesion. The results failed to reject the null hypothesis. The scanning electron microscopy revealed completely adapted adhesive interfaces underneath the restorations along with well-developed hybrid layers depending on the adhesive system. Energy dispersive X-ray analysis analyses showed that the restorative materials have similar chemical compositions, with some differences between the samples from the same material. The results support the implementation of experimental resins in clinical settings.

Biological Amnion Prevents Flexor Tendon Adhesion in Zone II: A Controlled, Multicentre Clinical Trial.

INTRODUCTION: Tendon adhesion to surrounding tissues is the most common complication reported after tendon repair. To date, effective solutions to prevent tendon injury are still lacking. MATERIALS AND METHODS: A total of 89 patients with flexor tendon injury in zone II were recruited. The patients were divided into a control group, a poly-DL-lactic acid (PDLLA) group, and an amnion group according to the different tendon treatments applied. The control group was not subjected to other treatments. PDLLA and bioamniotic membranes were, respectively, used to wrap broken ends in the PDLLA and amnion membrane groups. The patients were followed at 1, 2, 3, 6, and 12 months after surgery and the ranges of active flexion and extension lag in the proximal and distal interphalangeal joints were evaluated. RESULTS: The means of total active ranges of motion of the interphalangeal joints (excluding rupture cases) in the PDLLA and amnion groups did not significantly differ between each other but significantly differed from that of the control group. Statistical analysis showed a significant difference in the clinical grades of the outcomes among the control, PDLLA, and amnion groups. The incidence of complications in the control and PDLLA groups was found to be significantly higher than that in the amniotic membrane group; no significant difference was observed between the control and PDLLA groups. CONCLUSION: In this study, freeze-dried amniotic membrane transplantation was applied to promote healing of the flexor tendon in zone II and prevent adhesion. This technique presents a new method to solve the issue of tendon adhesion after repair. CLINICAL TRIAL REGISTRATION: The trial was registered by identifier ChiCTR1900021769.

The Effect of Extensor Tendon Adhesions on Finger Motion.

PURPOSE: To quantify the amount and pattern of finger range of motion loss at the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints with a simulated extensor tendon adhesion at the level of the proximal phalanx or metacarpal. METHODS: In 10 cadaveric specimens, traction sutures were placed in the forearm extensor digitorum communis and flexor digitorum profundus tendons of the middle and ring fingers. Active motion was simulated by suspending weights from the traction sutures via pulleys. The angles of the MCP, PIP, and DIP joints were measured at the position of maximum flexion and extension. Extensor tendon adhesions were simulated alternately at the proximal phalanx and metacarpal levels of the middle and ring fingers, using suture anchors. Repeat measurements were taken using the same amount of force. RESULTS: There was an average total loss of flexion of 38° and of extension of 6° with a proximal phalanx adhesion, with a greater contribution of flexion loss at the PIP joint. The loss of flexion was 17° and of extension was 50° with a metacarpal adhesion, with a loss of extension mostly at the MCP joint. CONCLUSIONS: The results of this study identified clear patterns of motion loss that are associated with isolated simulated adhesions in different locations along the extensor mechanism. The greatest motion loss occurred at the joint immediately distal to the simulated adhesion. CLINICAL RELEVANCE: Although extrapolation of these findings to clinical relevance remains unclear, the ability to predict the level of adhesion by the pattern of motion restriction may allow for a targeted tenolysis procedure. This would reduce the amount of soft tissue dissection required, which in turn, could be expected to reduce the degree of repeat adhesion formation.

Multi-scale modeling of an upper respiratory airway: Effect of mucosal adhesion on Eustachian tube function in young children.

BACKGROUND: The Eustachian tube is a collapsible upper respiratory airway that is periodically opened to maintain a healthy middle ear. Young children, <10 years old, exhibit reduced Eustachian tube opening efficiency and are at risk for developing middle ear infections. Although these infections increase mucosal adhesion, it is not known how adhesion forces alters the biomechanics of Eustachian tube opening in young children. This study uses computational techniques to investigate how increased mucosal adhesion alters Eustachian tube function in young children. METHODS: Multi-scale finite element models were used to simulate the muscle-assisted opening of the Eustachian tube in healthy adults and young children. Airflow during opening was quantified as a function of adhesion strength, muscle forces and tissue mechanics. FINDINGS: Although Eustachian tube function was sensitive to increased mucosal adhesion in both adults and children, young children developed Eustachian tube dysfunction at significantly lower values of mucosal adhesion. Specifically, the critical adhesion value was 2 orders of magnitude lower in young children as compared to healthy adults. Although increased adhesion did not alter the sensitivity of Eustachian tube function to tensor and levator veli palatini muscles forces, increased adhesion in young children did reduced the sensitivity of Eustachian tube function to changes in cartilage and mucosal tissue stiffness. INTERPRETATIONS: These results indicate that increased mucosal adhesion can significantly alter the biomechanical mechanisms of Eustachian tube function in young children and that clinical assessment of adhesion levels may be important in therapy selection.