As a result of the low yield of cartilage from primary patient harvests and a high demand for autologous cartilage for reconstructive surgery and structural repair, primary explant cartilage must be augmented by tissue engineering techniques. In this study, chondrocytes seeded on PLLA/PGA scaffolds in static culture and a direct perfusion bioreactor were biochemically and histologically analyzed to determine the effects of fluid flow and media pH on matrix assembly. A gradual media pH change was maintained in the bioreactor within 7.4−6.96 over 2 weeks compared to a more rapid decrease from 7.4 to 6.58 in static culture over 3 days. Seeded scaffolds subjected to 1 μm/s flow demonstrated a 118% increase (p < 0.05) in DNA content, a 184% increase (p < 0.05) in GAG content, and a 155% (p< 0.05) increase in hydroxyproline content compared to static culture. Distinct differences were noted in tissue morphology, including more intense staining for proteoglycans by safranin‐O and alignment of cells in the direction of media flow. Culture of chondrocyte seeded matrices thus offers the possibility of rapid in vitro expansion of donor cartilage for the repair of structural defects, tracheal injury, and vascularized tissue damage.

In this Journal Club review, we critically examine the methodology and results of a recently published meta-analysis describing the time dependency of surgical outcomes associated with cauda equina syndrome (CES) diagnosis. Our objectives are to clarify the strengths, weaknesses, and appropriate use of statistics regarding the findings of the previous publication. Surgical outcomes from published reports are related to both preoperative conditions and the time between surgery and diagnosis of CES. We reexamined many of the papers that were used to create the surgical outcomes data set, including the publications that supplied quantitative information for logistic regression. Of special focus were studies that contributed to the “less than 24 hours from diagnosis” data. The use of statistical parameters such as probabilities and odds ratios to infer possible future outcomes is also addressed to clarify the papers’ interpretations. To support the overall limitations of their generalized findings, we conducted a power analysis, which highlights the lack of statistical strength in the resulting conclusions. The results of the initial work state that an advantage exists in treating patients within 48 hours in comparison to treating them during a period greater than 48 hours after the onset of CES symptoms. However, the authors also state that no difference exists between the effects of an early surgery (less than 24 hours) compared with a subsequent period between 24 and 48 hours after CES onset. Key elements of logistic regression and meta-analysis are used to refute specific aspects of their methodology as well as their clinical interpretation regarding acute intervention. We conclude that a flawed methodology and misinterpretation of results are reported, understating the value of early surgical intervention.