Background/Objectives: The porcine mammary anatomy is poorly characterized, and structures are difficult to differentiate macroscopically, unlike human mammary tissue. The objective of this exploratory study was to describe the Yucatan porcine breast tissue morphology and identify the basic differences and similarities to human breast tissue. Methods: Samples from an adult, non-parous female Yucatan pig were prepared utilizing various methods: freezing at −80 °F (−26.67 °C) with a thickness of 0.5 cm/post-fixation in formalin; freezing at −20 °F (−6.67 °C) with a thickness of 0.5 cm/post-fixation in formalin; or formalin fixed and incised at ~0.8 cm. A descriptive comparison of the gross and microscopic images of the porcine breast morphology to the previously described human breast anatomy was performed. Results: As examined grossly, frozen sections allowed narrower serial cross-sectioning and better visualization of the structures and relationships. The mammary glands were poorly demarcated with extensive interspersed adipose tissue throughout the periphery. The mammary tissue appeared grossly as pigmented tissue and extended within ~0.5 cm from the skin surface, ~2.0 cm deep (within ~0.5 cm of the deep muscle layer), and ~6.5 cm laterally (centered on a teat). There were a number of similarities between Yucatan porcine and human breast tissue, yet there were several inherent structural differences. In contrast to human mammary tissue, porcine mammary glands consist of more diffuse acinar tissue, less well demarcated by defined fascial, lamellar, and ligamentous structures. Conclusions: The Yucatan porcine mammary morphology and similarities to the human mammary region allow for the use of this animal model to guide those developing relevant technologies or performing local surgical interventions in the preclinical setting.

Background: Effective hemostasis in spinal surgery is critical, especially near sensitive structures such as the spinal cord and dorsal root ganglia. Flowable hemostatic agents offer targeted control in irregular, hard-to-reach areas. This study evaluates the safety and efficacy of flowable collagen hemostat (FC) in an ovine lumbar laminectomy model with open durotomy by making a direct comparison with the gelatin hemostatic matrix with thrombin (GM) and a no-treatment control (Sham). Methods: Fifty-four Polypay sheep (27 F, 27 M) underwent lumbar laminectomy and open durotomy and then received FC, GM, or no treatment ( n = 18/group). Hemostasis was assessed at 3 min postapplication without tamponade. Neurological examinations were performed at periodic intervals, and tissues were collected on days 7, 45, and 120 for a histological analysis. Results: Hemostasis was achieved in 100% of FC-treated sites, 94.4% of GM, and 72.2% of Sham. Sham-treated animals exhibited more severe and prolonged neurological deficits compared with those treated with FC or GM. Inflammation decreased significantly across all groups, from mild/moderate on day 7 to minimal on day 45, and was barely detectable by day 120. FC was associated with favorable histological responses in both intradural and extradural spinal tissues, comparable to GM and Sham. Conclusion: Flowable collagen hemostat was safe and effective when applied directly to the spinal cord and surrounding neurological tissues during laminectomy with open durotomy. Its performance was comparable to that of the gelatin hemostatic matrix with thrombin in terms of hemostatic efficacy and histological outcomes, with both agents demonstrating superior neurological recovery compared with the untreated Sham group.