Computed tomography, electrodiagnostic and clinical findings in chronic workers' compensation patients with back and leg pain

One hundred patients with complaints of low-back pain and leg pain, consistent with a diagnosis of sciatica, were evaluated. All patients had complaints for longer than 6 months and had recently undergone electrodiagnostic testing and computed tomography (CT). Correlation was made between symptoms, straight leg raising, clinical neurological deficits, electrodiagnostic and CT findings. The radiation of pain above or below the knee and pain on straight leg raising did not show a high correlation with each other or with neurological deficits or CT findings. Electrodiagnostic studies often defined a radiculopathy in patients with equivocal clinical signs. CT findings did not predict the nature of symptoms or clinical and electrodiagnostic findings. Electrodiagnostic abnormalities showed the greatest ability to predict CT abnormalities. It is concluded that in chronic sciatica patients, no single diagnostic parameter is conclusive and a combination of clinical and laboratory findings is necessary to reach a diagnosis. In addition, many assumptions, valid in patients with acute pain cannot be extrapolated to patients with chronic sciatica.     

Recent Progress Toward Clinical Translation of Tissue-Engineered Heart Valves

Surgical replacement remains the primary option to treat the rapidly growing number of patients with severe valvular heart disease. Although current valve replacements—mechanical, bioprosthetic, and cryopreserved homograft valves—enhance survival and quality of life for many patients, the ideal prosthetic heart valve that is abundantly available, immunocompatible, and capable of growth, self-repair, and life-long performance has yet to be developed. These features are essential for pediatric patients with congenital defects, children and young adult patients with rheumatic fever, and active adult patients with valve disease. Heart valve tissue engineering promises to address these needs by providing living valve replacements that function similarly to their native counterparts. This is best evidenced by the long-term clinical success of decellularised pulmonary and aortic homografts, but the supply of homografts cannot meet the demand for replacement valves. A more abundant and consistent source of replacement valves may come from cellularised valves grown in vitro or acellular off-the-shelf biomaterial/tissue constructs that recellularise in situ, but neither tissue engineering approach has yet achieved long-term success in preclinical testing. Beyond the technical challenges, heart valve tissue engineering faces logistical, economic, and regulatory challenges. In this review, we summarise recent progress in heart valve tissue engineering, highlight important outcomes from preclinical and clinical testing, and discuss challenges and future directions toward clinical translation.     

Design of a Mechanobioreactor to Apply Anisotropic,Biaxial Strain to Large Thin Biomaterials for Tissue Engineered Heart Valve Applications

Repair and replacement solutions for congenitally diseased heart valves capable of post-surgery growth and adaptation have remained elusive. Tissue engineered heart valves (TEHVs) offer a potential biological solution that addresses the drawbacks of existing valve replacements. Typically, TEHVs are made from thin, fibrous biomaterials that either become cell populated in vitro or in situ. Often, TEHV designs poorly mimic the anisotropic mechanical properties of healthy native valves leading to inadequate biomechanical function. Mechanical conditioning of engineered tissues with anisotropic strain application can induce extracellular matrix remodelling to alter the anisotropic mechanical properties of a construct, but implementation has been limited to small-scale set-ups. To address this limitation for TEHV applications, we designed and built a mechanobioreactor capable of modulating biaxial strain anisotropy applied to large, thin, biomaterial sheets in vitro. The bioreactor can independently control two orthogonal stretch axes to modulate applied strain anisotropy on biomaterial sheets from 13 × 13 mm² to 70 × 40 mm². A design of experiments was performed using experimentally validated finite element (FE) models and demonstrated that biaxial strain was applied uniformly over a larger percentage of the cell seeded area for larger sheets (13 × 13 mm²: 58% of sheet area vs. 52 × 31 mm²: 86% of sheet area). Furthermore, bioreactor prototypes demonstrated that over 70% of the cell seeding area remained uniformly strained under different prescribed protocols: equibiaxial amplitudes between 5 to 40%, cyclic frequencies between 0.1 to 2.5 Hz and anisotropic strain ratios between 0:1 (constrained uniaxial) to 2:1. Lastly, proof-of-concept experiments were conducted where we applied equibiaxial (ε_x = ε_y = 8.75%) and anisotropic (ε_x = 12.5%, ε_y = 5%) strain protocols to cell-seeded, electrospun scaffolds. Cell nuclei and F-actin aligned to the vector-sum strain direction of each prescribed protocol (nuclei alignment: equibiaxial: 43.2° ± 1.8°, anisotropic: 17.5° ± 1.7°; p < 0.001). The abilities of this bioreactor to prescribe different strain amplitude, frequency and strain anisotropy protocols to cell-seeded scaffolds will enable future studies into the effects of anisotropic loading protocols on mechanically conditioned TEHVs and other engineered planar connective tissues.

     

Three-dimensional hysterosalpingo-contrast sonography (3D-HyCoSy) as an outpatient procedure to assess infertile women: a pilot study.

OBJECTIVES: This study aimed to assess the use of three-dimensional hysterosalpingo-contrast sonography (3D-HyCoSy) as a routine outpatient procedure for evaluating infertile women. METHODS: In 25 unselected infertile patients, tubal patency and uterine cavity were investigated by 3D-HyCoSy with saline as a contrast medium. The efficacy of the procedure was evaluated with X-ray hysterosalpingography (XHSG) as reference. RESULTS: The positive predictive value, negative predictive value, sensitivity, and specificity of predicting tubal patency by 3D-HyCoSy were 100, 33.3, 84.4, and 100%, respectively. The full contour of the uterine cavity was depicted in 96% of cases by 3D-HyCoSy and 64% by XHSG (P < 0.005). The uterine cavity area measured on 3D-HyCoSy correlated well with the volume of contrast medium required on XHSG (r2 = 0.8166). CONCLUSIONS: 3D-HyCoSy provided advantages of better assessment of uterine cavity over XHSG. Compared with conventional XHSG, the efficacy of 3D-HyCoSy to assess tubal patency was acceptable. In addition, the procedure of 3D-HyCoSy appears to be better tolerated, requiring no sedation or anesthesia and a reduced examination time. Thus, 3D-HyCoSy with saline as a contrast medium is feasible and could comprise a routine outpatient procedure in the initial evaluation of infertile women.