RESUMO
Background: To evaluate if Hounsfield units (HU) measured on preoperative computed tomography (CT) scans at the anatomic neck of the proximal humerus correlates with intraoperative findings of the "thumb test" in assessment of bone quality in shoulder arthroplasty patients. Methods: Primary anatomic total shoulder and reverse total shoulder arthroplasty patients from 2019-2022 with an available preoperative CT scan of the operative shoulder were prospectively enrolled at a single center with 3 surgeons who perform shoulder arthroplasty. The "thumb test" was performed intraoperatively; a positive test signified "good bone." Demographic information, including prior dual x-ray absorptiometry scans, was extracted from the medical record. HU at the cut surface of the proximal humerus were calculated, as was cortical bone thickness on preoperative CT. Fracture risk assessment tool (FRAX) scores were calculated for 10-year risk of osteoporotic fracture. Results: A total of 149 patients were enrolled. Mean age was 67.6 ± 8.5 years with 69 (46.3%) being males. Patients with a negative thumb test were significantly older (72.3 ± 6.6 vs. 66.5 ± 8.6 years; P < .001) than those with a positive thumb test. Males were more likely to have a positive thumb test than females (P = .014). Patients with a negative thumb test had significantly lower HUs on preoperative CT (16.3 ± 29.7 vs. 51.9 ± 35.2; P < .001). Patients with a negative thumb test had a higher mean FRAX score (14.1 ± 7.9 vs. 8.0 ± 4.8; P < .001). Receiver operator curve analysis was performed to identify a cut-off value for CT HU of 36.67, above which the thumb test is likely to be positive. Furthermore, receiver operator curve analysis also identified optimal cut-off values for 10-year risk of fracture by FRAX score of 7.75 HU, below which the thumb test is likely to be positive. Fifty patients were at high risk based on FRAX and HU; surgeons classified 21 (42%) as having "poor bone" quality through a negative thumb test. High-risk patients had a negative thumb test 33.8% (23/68) and 37.1% (26/71) of the time for HU and FRAX, respectively. Conclusions: Surgeons are poor at identifying suboptimal bone quality at the anatomic neck of the proximal humerus based on intraoperative thumb test when referencing against CT HU and FRAX scores. The objective measures of CT HU and FRAX scoring may be useful metrics to incorporate into surgeons' preoperative plans for humeral stem fixation using readily available imaging and demographic data.
RESUMO
OBJECTIVES/HYPOTHESIS: Resonance tubes are commonly used in voice therapy. These devices modify supraglottal impedance, potentially decreasing the aerodynamic power necessary for phonation. We modeled phonation with resonance tubes in excised larynges and evaluated the effects of varying tube width, tube length, and flow input on phonation threshold pressure (PTP) and phonation threshold flow (PTF). We hypothesized that the increased vocal economy observed in human subjects and several other models would be observed in excised larynges. STUDY DESIGN: Repeated measures excised canine larynx bench experiment with each larynx serving as own control. METHODS: Nine conditions were evaluated, namely control, two tube diameters (17.5 and 6.5mm), three tube lengths (7.8, 15.0, and 30.0cm), and three levels of flow input (80, 114, and 200mL/s). Aerodynamic data were collected for 11 excised canine larynges attached to an artificial vocal tract, and results from each experimental configuration were compared with control. RESULTS: A significant decrease in average PTP occurred compared with control for the 114- and 200-mL/s flow inputs, 30-cm extension, and 17.5- and 6.5-mm constrictions. Average PTF decreased compared with control for every configuration, although statistically significant changes were only observed for 200-mL/s flow and 6.5-mm constriction. CONCLUSIONS: Knowledge regarding the effect of vocal tract alterations could be clinically useful in determining the optimal "straw" configuration for voice therapy. Further exploration of the relationships among width, length, and flow input could provide theoretical support for the development of new therapies and resonance tube devices.
