Fully Implanted Prostheses for Musculoskeletal Limb Reconstruction After Amputation: An In Vivo Feasibility Study.

Previous prostheses for replacing a missing limb following amputation must be worn externally on the body. This limits the extent to which prostheses could physically interface with biological tissues, such as muscles, to enhance functional recovery. The objectives of our study were to (1) test the feasibility of implanting a limb prosthesis, or endoprosthesis, entirely within living skin at the distal end of a residual limb, and (2) identify effective surgical and post-surgical care approaches for implanting endoprostheses in a rabbit model of hindlimb amputation. We iteratively designed, fabricated, and implanted unjointed endoprosthesis prototypes in six New Zealand White rabbits following amputation. In the first three rabbits, the skin failed to heal due to ishemia and dehiscence along the sutured incision. The skin of the final three subsequent rabbits successfully healed over the endoprotheses. Factors that contributed to successful outcomes included modifying the surgical incision to preserve vasculature; increasing the radii size on the endoprostheses to reduce skin stress; collecting radiographs pre-surgery to match the bone pin size to the medullary canal size; and ensuring post-operative bandage integrity. These results will support future work to test jointed endoprostheses that can be attached to muscles.

A Phyllodes-like Mammary Tumor in a Breeding Galago (Otolemur garnettii).

In humans, phyllodes tumors of the breast are rare fibroepithelial tumors that are further characterized as benign, borderline, or malignant according to their histomorphologic features. Phyllodes tumors are poorly responsive to treatment other than excision. NHP have a much lower frequency of mammary neoplasia than do humans, and none of the lesions reported previously in NHP are consistent with phyllodes tumors. Here we present the case of a mammary tumor in a northern greater galago (Otolemur garnettii) that was histologically characteristic of a malignant phyllodes tumor. An 11-y-old, multiparous, pregnant galago presented with a mass in the right middle mammary gland. A fine-needle aspirate yielded neoplastic epithelial cells. Because the animal was pregnant and showed no signs of skin ulceration, pain, or distress, she was allowed to deliver and nurse the infant. At 20 wk after initial presentation, the infant was weaned and the mother was euthanized. At necropsy, the mammary mass measured 3.5 × 2.5 × 1.5 cm, a 13-fold increase in volume since initial presentation. There was no evidence of metastasis in draining lymph nodes, lungs, or any other tissue examined. The tumor was composed of neoplastic stromal, glandular, and adipose tissues and was diagnosed as a malignant phyllodes tumor in light of its high stromal cellularity, high mitotic rate, and marked atypia. This tumor also exhibited liposarcomatous differentiation, which occurs frequently in malignant phyllodes tumors. To our knowledge, this report represents the first described case involving an NHP of a mammary tumor with characteristics consistent with human phyllodes tumors.

Isolation of Trueperella pyogenes in a case of thoracic and abdominal abscess in a galago (Otolemur garnettii).

BACKGROUND: An adult male galago (Otolemur garnettii) presented for fight wounds following pairing for breeding. Treatment was symptomatic with recovery. Following resolution, the animal re-presented and died, despite additional treatment. METHODS: Necropsy, histopathology, bacterial cultures, and 16S RNA sequencing. RESULTS: A large intrathoracic/intra-abdominal abscess due to Trueperella pyogenes was found at necropsy. CONCLUSIONS: T. pyogenes should be considered in abscesses/wounds of galagos.