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There is currently a lack of clinically available solutions to restore functionality to the intervertebral disk (IVD) following herniation injury to the annulus fibrosus (AF). Microdiscectomy is a commonly performed surgical procedure to alleviate pain caused by herniation; however, AF defects remain and can lead to accelerated degeneration and painful conditions. Currently available AF closure techniques do not restore mechanical functionality or promote tissue regeneration, and have risk of reherniation. This review determined quantitative design requirements for AF repair materials and summarized currently available hydrogels capable of meeting these design requirements by using a series of systematic PubMed database searches to yield 1500+ papers that were screened and analyzed for relevance to human lumbar in vivo measurements, motion segment behaviors, and tissue level properties. We propose a testing paradigm involving screening tests as well as more involved in situ and in vivo validation tests to efficiently identify promising biomaterials for AF repair. We suggest that successful materials must have high adhesion strength (∼0.2 MPa), match as many AF material properties as possible (e.g., approximately 1 MPa, 0. 3 MPa, and 30 MPa for compressive, shear, and tensile moduli, respectively), and have high tensile failure strain (∼65%) to advance to in situ and in vivo validation tests. While many biomaterials exist for AF repair, few undergo extensive mechanical characterization. A few hydrogels show promise for AF repair since they can match at least one material property of the AF while also adhering to AF tissue and are capable of easy implantation during surgical procedures to warrant additional optimization and validation.

Abstract:Herniated intervertebral discs are a common cause of back and neck pain. There is an unmet clinical need to seal annulus fibrosus (AF) defects, since discectomy surgeries address acute pain but are complicated by reherniation and recurrent pain.Copolymers of polyethylene glycol with trimethylene carbonate (TMC) and hexamathylene diisocyanate end-groups were formulated as AF sealants since the hexamathylene diisocyanate form covalent bonds with native AF tissue. TMC adhesives were evaluated and optimized using the design criteria: stable size, strong adherence to AF tissue, high cytocompatibility, restoration of intervertebral disc biomechanics to intact levels following in situ repair, and low extrusion risk. TMC adhesives had high adhesion strength as assessed with a pushout test (150 kPa), and low degradation rates over three weeks in vitro. Both TMC adhesives had shear moduli (220 & 490kPa) similar to, but somewhat higher than AF tissue. The adhesive with three TMC moieties per branch (TMC3) was selected for additional in situ testing because it best matched AF shear properties. TMC3 restored torsional stiffness, torsional hysteresis area and axial range of motion to intact states.However, in a failure test of compressive deformation under fixed 5° flexion, some herniation risk was observed with failure strength of 5.9 MPa compared to 13.5 MPa for intact samples; TMC3 herniated under cyclic organ culture testing. These TMC adhesives performed well during in vitro and in situ testing, but additional optimization to enhance failure strength is required to further this material to advanced screening tests such as long term degradation.

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Results: 139 patients (33 men, 106 women, mean age 57.4 years) were analyzed. 77 (55.4%) patients had ports placed with LE; 62 (44.6%) with L. 3 ports (2.2%) were removed because of hematoma and/or infection. No significant difference in mean procedure time between the two groups (23.6 (SD 6.4) LE vs 25.1 (SD 10.4) L, P ¼ 0.30) was observed. Among operators utilizing sharp dissection techniques, significant differences in mean procedure time were observed (19.2 (SD 4.3) LE vs 25.4 (SD 8.5) L, P ¼ 0.02). No significant differences were observed in those operators utilizing blunt dissection techniques (24.5 (SD 6.4) LE vs 25.0 (SD 10.8) L, P ¼ 0.74). Conclusions: No significant differences in procedural time or procedural complications were observed in patients receiving LE compared to L. Operators utilizing sharp dissection techniques may benefit from the use of LE for local anesthesia.Purpose: Stenosis is a common complication of renal dialysis arteriovenous (AV) fistulas, leading to poor maturation, thrombosis, and loss of haemodialysis access.[1] Recent studies propose the use of drug-eluting balloon (DEB) over standard balloon angioplasty (POBA) for AV fistula stenosis.[2] We report our JVIR ▪ Scientific e-Posters S263 Scientific e-Posters

between poor postoperative glycemic control and 30-day mortality. Further investigation is needed to clearly characterize "true" uncontrolled perioperative hyperglycemia and define a level at which we must take action to reduce adverse outcomes.

Paracenteses are considered safe procedures; however, in patients with portal hypertension, the rapid shifts in intraabdominal pressure can prompt hemorrhage from an ectopic varix. Little literature exists on the appropriate management in this clinical setting. Here, we describe a patient with portal hypertension secondary to Budd-Chiari syndrome, presenting with massive hemoperitoneum following paracentesis. Angiography was performed, without revealing an arterial source of bleeding. Subsequently, transjugular intrahepatic portosystemic shunt placement was performed via a recanalized middle hepatic vein, reducing the patient's portosystemic gradient from 15 to 6 mm Hg. This patient developed no further signs or symptoms of bleeding and remained hemodynamically stable until discharge. Follow-up imaging confirmed patency of her shunt and resolution of her ascites, without the need for future paracentesis. This case highlights that in the absence of arterial extravasation, the possibility of ectopic variceal hemorrhage should be considered, which can be successfully treated with portosystemic shunt creation.