Insertional characteristics of three types of transfixation pin taps in third metacarpal bones from equine cadavers.

OBJECTIVE: To compare heat generation and mechanical bone damage achieved with 2 tapered and 1 cylindrical transfixation pin taps in third metacarpal bones from equine cadavers. SAMPLE: 18 pairs (36 specimens) of third metacarpal bones from euthanized horses with no known metacarpal disease. PROCEDURES: In each bone, an investigator drilled 3 holes for placement of a 6.3-mm cylindrical transfixation pin, a 6.3-mm tapered pin using a prototype tapered tap, and a 6.3-mm tapered pin using a revised tapered tap. One bone of each pair was tapped by hand and the other with an electric drill. Temperatures of the drill bits, reamers, and taps were measured and used to compare heat generation among tap groups and tapping methods (hand vs power tapping). Macrodamage (all bone pairs) and microdamage (6 bone pairs) were assessed. RESULTS: The revised tapered tap resulted in less heat generation and less total thread microdamage, compared with the prototype tapered and cylindrical taps. Power tapping created less bone damage but higher temperatures than did hand tapping for all bone groups. CONCLUSIONS AND CLINICAL RELEVANCE: The revised tap design for tapered pin insertion was superior to the prototype tap design and yielded similar or less bone damage than achieved with cylindrical pin insertion in equine third metacarpal bone specimens. We recommend careful hand tapping for tapered pin insertion rather than power tapping, which generated greater heat. The revised tapered tap could be expected to perform better than a cylindrical pin tap in terms of thermal and mechanical microdamage and should be used for insertion of tapered transfixation pins.

Silent aspiration: Who is at risk?

OBJECTIVE: To determine the prevalence of silent aspiration in pediatric patients and identify which diagnoses may be associated with this finding. METHODS: An institutional review board-approved retrospective review was conducted for all patients under the age of 18 who underwent modified barium swallow (MBS) studies at a tertiary children's hospital in 2015. Speech-language pathologists reviewed MBS studies to identify aspiration/silent aspiration on each fluid consistency tested. Charts were reviewed to collect demographic information and the otolaryngologic, neurologic, genetic, and syndromic diagnoses of each patient. RESULTS: Among 1,286 patients who underwent MBS, 440 (34%) demonstrated aspiration. Within the aspiration group, 393 (89%) specifically demonstrated silent aspiration. Thin fluids were silently aspirated in 81% of these patients. Of children aged <6 months, 41% were found to aspirate and, of those, 95% silently aspirated. Median age at which patients demonstrated silent aspiration was 1.1 years. Silent aspiration was documented in 41% of patients with laryngeal cleft, 41% of patients with laryngomalacia, and 54% of patients with unilateral vocal fold paralysis. Laryngeal cleft, laryngomalacia, unilateral vocal fold paralysis, developmental delay, epilepsy/seizures, syndrome, and congenital heart disease were all associated with silent aspiration. CONCLUSION: Silent aspiration may be associated with a number of underlying conditions and is more common than previously described. Caregivers and clinicians should be aware that the absence of cough does not eliminate the possibility of aspiration. Modified barium swallow studies can reveal silent aspiration, which is difficult to detect on clinical feeding evaluation. Modified barium swallow findings can guide feeding therapy and the overall management of aspiration. LEVEL OF EVIDENCE: 4. Laryngoscope, 1952-1957, 2018.

Evaluation of the ability of a gravitational filtration system to enhance recovery of equine bone marrow elements.

OBJECTIVE: To assess efficiency of gravity filtration to enhance recovery of equine bone marrow elements including stem and progenitor cells. ANIMALS: 12 healthy adult horses. PROCEDURES: Bone marrow aspirates were collected from the fifth sternebral body and filtered by gravitational flow to obtain bone marrow elements. Raw and harvested bone marrow and marrow effluent were evaluated for WBC and platelet counts, automated and cytomorphologic cell differential counts, mesenchymal stem cell CFUs, cell viability, and differentiation capacity. Isolated cells were analyzed for CD90 and major histocompatibility complex (MHC) class I and II antigens. RESULTS: Mean cell viability of harvested bone marrow was 95.9%. Total WBCs and platelets were efficiently captured on the filter (> 95%), and mean recovery in harvested bone marrow was 30%. Cytologic cell differential counts indicated that the percentage of neutrophils was significantly less and the progenitor cell population was significantly higher and concentrated 1.56-fold in harvested bone marrow, compared with results for raw bone marrow. Flow cytometry and cell culture were used to characterize harvested bone marrow cells as positive for expression of CD90 and negative for MHCI and MHCII, which indicated stem cells with a multipotent phenotype that differentiated into chondrocytes, osteocytes, adipocytes, and tenocytes. CONCLUSIONS AND CLINICAL RELEVANCE: Gravitational filtration of bone marrow efficiently yielded platelets and cells and produced a progenitor-enriched, leukocyte-reduced product, compared with raw bone marrow.