The long head of the biceps tendon undergoes multiaxial deformation during shoulder motion.

The long head biceps tendon (LHBT) is presumed a common source of shoulder joint pain and injury. Despite common LHBT pathologies, diagnosis and preferred treatment remain frequently debated. This Short Communication reports the development of a subject-specific finite element model of the shoulder joint based on one subject's 3D reconstructed anatomy and 3D in vivo kinematics recorded from bone-fixed electromagnetic sensors. The primary purpose of this study was to use the developed finite element model to investigate the LHBT mechanical environment during a typical shoulder motion of arm raising. Furthermore, this study aimed to assess the viability of material models derived from uniaxial tensile tests for accurate simulation of in vivo motion. The findings of our simulations indicate that the LHBT undergoes complex multidimensional deformations. As such, uniaxial material properties reported in the existing body of literature are not sufficient to simulate accurately the in vivo mechanical behavior of the LHBT. Further experimental tests on cadaveric specimens, such as biaxial tension and combinations of tension and torsion, are needed to describe fully the mechanical behavior of the LHBT and investigate its mechanisms of injury.

Changes of incudostapedial joint angle in stapedotomy: does it impact hearing outcomes?

PURPOSE: The aims of this article are: (1) is there an ideal incudostapedial joint (ISJ) angle after stapedotomy? (2) is there any difference between pre- and postoperative ISJ angle? and (3) what is the significance of the ISJ angle in postoperative hearing outcomes? METHODS: Forty six ears from 39 different adult patients (28 women and 11 men; 21 left and 25 right ears) with a mean age of 39 years with clinical otosclerosis who underwent stapedotomy between May 2017 and May 2019 were retrospectively registered, including seven bilateral surgery cases. ISJ angle and intravestibular depth of the stapes prosthesis were measured from multiple planar reconstruction-computed tomography images and the length of the prosthesis was measured during surgery. Relationships between the ISJ angle parameters and postoperative hearing outcomes and parameters of the prosthesis were analyzed. RESULTS: The mean ISJ angle was 93.3° ± 8.8° preoperatively and 101.9° ± 6.3° postoperatively, increasing by 8.6° during stapedotomy (p < 0.01). There were weak and negative correlations between ISJ angle changes and postoperative air conduction gains at frequencies ≤1 kHz and bone conduction gains at 0.5 kHz. When the postoperative ISJ angle changed more than 20°, the success rate of the procedure decreased to 0%. CONCLUSION: The stapedotomy operation increased the ISJ angle. The success of postoperative auditory outcomes had more to do with the ISJ angle change than the value of the angle itself, indicating there is no universal ideal ISJ angle that surgeons should aim for during stapedotomy.

Cryotherapy has antifibrotic and regenerative effects on human vocal fold fibroblasts.

OBJECTIVES/HYPOTHESIS: Vocal fold scarring remains a major treatment challenge, and scar prevention without residual lesions remains a dilemma. Cryotherapy has shown cosmetic outcomes on skin lesions with minimal scarring. The aim of this study was to clarify the beneficial effects of cryotherapy for the prevention and the treatment of vocal fold scarring. STUDY DESIGN: In vitro. METHODS: Primary cultures of human vocal fold fibroblasts (VFFs) were used in this study. Myofibroblast differentiation was stimulated by transforming growth factor ß1 (TGF-ß1). We mimicked the cryotherapy effect on vocal fold healing in vivo by freezing VFFs ± TGF-ß1 in vitro. The influence of freezing on cell viability, proliferation, migration, and contractile properties were analyzed. The expression of collagen I, collagen III, fibronectin, TGF-ß1, matrix metallopeptidase 1 (MMP1), hyaluronan synthase 1 (HAS1) were investigated by real-time polymerase chain reaction (RT-PCR), and the expression of alpha smooth muscle actin (α-SMA) and decorin were investigated by RT-PCR and Western blot. RESULTS: Freezing was found to modify extracellular matrix (ECM) synthesis and differentiation of VFFs. Expression of collagen I, collagen III, fibronectin, α-SMA, and TGF-ß1 was downregulated, and MMP1 was upregulated in VFFs + TGF-ß1 (myofibroblast) by freezing. HAS1 and decorin were upregulated in both VFFs ± TGF-ß1 by freezing. Freezing VFFs + TGF-ß1 (myofibroblast) with fast thawing had a lower expression of α-SMA when compared with slow thawing. Freezing reduced the migration and collagen contraction of VFFs + TGF-ß1 (myofibroblast). CONCLUSION: Cryotherapy induces antifibrotic and regenerative ECM alterations in VFFs. These data provide insight into the prevention and the treatment of vocal fold scarring with cryotherapy in phonomicrosurgery. LEVEL OF EVIDENCE: NA Laryngoscope, 129:E143-E150, 2019.

Two-year evaluation of restorations of a packable composite placed in UK general dental practices.

OBJECTIVE: The aim of this study was to assess the clinical performance at two years of 100 Solitaire 2 restorations placed in five United Kingdom dental practices by members of a practice-based research group. METHOD AND MATERIALS: Restorations were assessed after two years by a trained evaluator and the dental practitioner who had placed the material, for anatomic form, marginal adaptation, surface roughness, gingival condition and the presence or absence of secondary caries. In addition, the patients completed a questionnaire requesting details of the comfort and performance of the Solitaire 2 restoration(s). RESULTS: A total of 88 (58 Class II and 30 Class I) restorations of Solitaire 2 placed in 49 patients (mean age 43 years) were assessed. Twelve restorations could not be evaluated because of patient unavailability for the dates of the examinations. Two Class II restorations (2%) had failed by the time of the two-year evaluation and the remaining 86 restorations were found to be intact with no secondary caries. A high percentage of optimal scores were recorded for anatomic form and surface roughness. The colour match of two restorations (2%) was recorded as an obvious mismatch, but otherwise no unacceptable scores were recorded. CONCLUSIONS: After two years of clinical service a high proportion (96%) of the Solitaire 2 restorations that were available for re-examination, placed in general dental practice settings, were found to be performing satisfactorily.

Treatment of dentinal hypersensitivity using a dentine bonding system.

AIMS AND OBJECTIVES: Many agents have been used in treatment of dentinal hypersensitivity in the past, but dentine bonding systems have recently been suggested as being effective. This study examined the effectiveness of a dentine bonding system in the treatment of dentinal hypersensitivity in dental practice conditions. METHODS: Dentists in two dental practices agreed to carry out the project. One practice was in the UK, the other in India. A total of 34 patients who were diagnosed to have dentinal hypersensitivity were treated using the dentine bonding system. Patients were requested to record their perception of their pain on a 100mm linear scale, pre-treatment, one day and one week post-treatment. RESULTS: All patients experienced relief of pain, both 1 day and 1 week after treatment. Profile plots of the patients' perceived pain scores for the two practices separately indicated that there was a general trend across both practices for these to fall quite sharply one day after treatment and then generally level out one week post-treatment. There was evidence indicating a possible difference in pain perception in the two communities from which the patients were drawn. CONCLUSION: The dentine bonding system evaluated was successful in reducing the pain of dentinal hypersensitivity, at least in the short term.