The TM implants supported bone growth into and around the implant margins better than the PEEK devices. TM's open cell porous structure facilitated host bone ingrowth and bone bridging through the device, which could be beneficial for long-term mechanical attachment and support in clinical applications.
Percutaneous osseointegrated (OI) prostheses (POPs) are used to skeletally attach artificial limbs in amputees. While any permanent percutaneous interface is at risk of becoming infected by the resident microbiota colonizing the stoma, most of these patients remain infection-free. Avoidance of infection likely depends upon a mechanically and/or biologically stable skin-to-implant interface. The ultimate question remains, "why do some stomata become infected while others do not?" The answer might be found in the dynamic bacterial communities of the patient and within the stomal site itself. This study is an appendix to the first Food and Drug Administration approved prospective early feasibility study of OI prosthetic docking, in which, 10 transfemoral amputees were implanted with a unique POP device. In this analytical, longitudinal cohort study, each patient's skin and stomal microbiota were analyzed from the initial surgery to 1 year following the second-stage surgery. During each follow-up visit, three swab samples-stomal, device thigh skin and contralateral thigh skin-were obtained. DNA was extracted, and bacterial 16S ribosomal RNA (rRNA) genes were amplified and sequenced to profile microbial communities. The stomal microbiota were distinct from the microbiota on the adjacent thigh skin and the skin of the contralateral thigh, with a significantly increased abundance of Staphylococcus aureus within the stoma. Early on stomal microbiota were characterized by high diversity and high relative abundance of obligate anaerobes. Over time, the stomal microbiota shifted and stabilized in communities of lower diversity dominated by Streptococcus, Corynebacterium, and/or Staphylococcus spp.
To gain an understanding of the vertebral cortical endplate and factors that may affect the ability to achieve skeletal attachment to intervertebral implants and fusion, this study aimed to characterize the hypermineralized tissue on the cortical endplate of the vertebral body on a commonly used animal model. Skeletally mature sheep were injected with tetracycline prior to euthanasia and the C2-C3, T5-T6, and L2-L3 spinal motion segments were excised and prepared. Vertebral tissues were imaged using backscatter electron (BSE) imaging, histology, and tetracycline labeling was used to assess bone remodeling within different tissue layers. It was determined that the hypermineralized tissue layer was calcified fibrocartilage (CFC). No tetracycline labels were identified in the CFC layer, in contrast to single and double labels that were present in the underlying bone, indicating the CFC present on the cortical endplate was not being actively remodeled. The average thickness of the CFC layer was 146.3 6 70.53 mm in the cervical region, 98.2 6 40.29 mm in the thoracic region, and 150.89 6 69.25 mm in the lumbar region. This difference in thickness may be attributed to the regional biomechanical properties of the spine. Results from this investigation indicate the presence of a nonremodeling tissue on the cortical endplate of the vertebral body in sheep spines, which attaches the intervertebral disc to the vertebrae. This tissue, if not removed, would likely prevent successful bony attachment to an intervertebral device in spinal fusion studies and total disc replacement surgeries. Anat Rec,
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