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Tissue engineering approaches to treatment of intervertebral disc degeneration (IDD) represent a novel avenue of addressing the biologic basis of this disease. However, such approaches remain limited by their invasive nature and disruption to the annular fibrosis (AF). This study sought to explore a new minimally-invasive tissue-engineering approach utilizing an injection of a photopolymerizable biogel scaffold seeded with mesenchymal stem cells (MSCs) directly into the nucleus pulposus (NP). This study was performed using rabbit specimens for both in vivo and in vitro outcome measures. The treatment in this study was performed by injecting 25 μl of 10% (w/v) methacrylated gelatin biogel with 0.15% (w/v) lithium phenyl 2,4,6-trimethylbenzoylphosphinate (LAP) and rabbit MSCs (1 × 106 ) cells/ml into the NP. Samples were then photopolymerized in situ using non-ultraviolet light irradiation via a fiberoptic wire. For the in vitro arm of this study, gene expression analysis demonstrated increased anabolic activity in irradiated MSCs with and without biogel scaffolds. For the in vivo arm of this study, while GAG analysis did not demonstrate significant differences between groups, MRI analysis exhibited a trend toward improved NP matrix. Histological analysis was consistent with increased cellularity and less severe disc degeneration in the MSC + Gel group. However, osteophyte formation was noted in both Stab and MSC + Gel groups after the study period. Increased matrix gene expression of irradiated groups within in vitro studies indicates a photobiologic effect of 405 nm light. Despite promising anabolic actions, osteophyte formation and AF defects could not be avoided with implementation of this minimally-invasive tissue-engineering approach. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1451-1459, 2019.

Two cases are presented of patients with a history of metastatic rectal adenocarcinoma presenting with a painful joint effusion. Both cases are potential examples of metastasis to periarticular bone with local infiltration to the synovium, which is one proposed mechanism of intrasynovial metastasis. While skeletal metastases are a relatively common occurrence in metastatic adenocarcinoma, intraarticular metastasis is extremely rare. These cases highlight the need to consider metastasis in the differential of joint swelling in the setting of a history of adenocarcinoma.

* ALT: : alanine aminotransferase AST: : aspartate aminotransferase BUN: : blood urea nitrogen CBC: : complete blood count CNS: : central nervous system CSF: : cerebrospinal fluid CT: : computed tomography ECG: : electrocardiography ED: : emergency department EEG: : electroencephalography ESR: : erythrocyte sedimentation rate GI: : gastrointestinal GU: : genitourinary Hct: : hematocrit Hgb: : hemoglobin MRI: : magnetic resonance imaging WBC: : white blood cell A 14-year-old boy is transferred from a local hospital. He was playing football and was struck in the abdomen by the head of another player who was wearing a helmet. He then fell on his abdomen. He immediately complained of left upper quadrant pain, and nausea. He was taken to a local ED and hospitalized. On admission, he was alert and oriented but experienced episodic hypotension. On examination, he looked pale and was found to have significant left upper quadrant abdominal tenderness. His initial Hct was 37%. Abdominal CT showed a 12×10×11 cm lobular enhancing mass over the left kidney, with questionable involvement of the colon and perinephric hematoma (Fig. 1). There was no free air. He was transfused with 1 unit of packed red blood cells and received 1 L of normal saline. His pain was controlled with morphine and he was transported to this institution. Figure 1. A CT scan of the abdomen shows a lobular enhancing mass over the left kidney. On arrival, he appears to be well developed and is in no acute distress, having a heart rate of 86 beats/min, respiratory rate of 20 breaths/min, blood pressure of 120/84 mm Hg, and oxygen saturation of 100% in room air. His abdomen is nondistended and has normal bowel sounds. However, he has left upper quadrant and left flank tenderness. Laboratory evaluations show Hct of 31.6%, normal coagulation studies and liver enzymes, lactose dehydrogenase concentration of 258 U/L (normal, 150 to 300 U/L), and urinalysis positive for blood and protein. Chest radiograph shows normal heart and lung fields. Additional investigation leads to the diagnosis. A 9-year-old girl presents with a 4-week history of a drooping right eyelid and occasional double vision. She does not complain of easy fatigability, and she is able to ride her bike long distances without …