Predicting surgical site infections following laparoscopic bariatric surgery: development of the BariWound tool using the MBSAQIP database.

BACKGROUND: Although bariatric surgery is a safe procedure for severe obesity, incisional surgical site infections (SSI) remain a significant cause of morbidity. Bariatric surgery patients are at high risk due to obesity and diabetes. The objective of this study was to develop a predictive tool for incisional SSI within 30 days of bariatric surgery. METHODS: Data were retrieved from the 2015 and 2016 MBSAQIP databases. This study included patients who underwent primary laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG). The primary outcome of interest was incisional SSI occurring within 30 days. Surgeries performed in 2015 were used in a derivation cohort and the predictive tool was validated against the 2016 cohort. A forward selection algorithm was used to build a logistic regression model predicting probability of SSI. RESULTS: A total of 274,187 patients were included with 71.7% being LSG and 28.3% LRYGB. 0.7% of patients had a SSI in which 71.0% had an incisional SSI, and 29.9% had an organ/space SSI. Of patients who had an incisional SSI, 88.7% were superficial, 10.9% were deep, and 0.4% were both. A prediction model to assess for risk of incisional SSI, BariWound, was derived and validated. BariWound consists of procedure type, chronic steroid or immunosuppressant use, gastroesophageal reflux disease, obstructive sleep apnea, sex, type 2 diabetes, hypertension, operative time, and body mass index. It stratifies individuals into very high (> 10%), high (5-10%), medium (1-5%), and low risk (< 1%) groups. This model accurately predicted events in the validation cohort with an area under the receiver operating characteristic curve of 0.73. CONCLUSIONS: BariWound accurately predicted the risk of 30-day incisional SSI in individuals undergoing bariatric surgery. Stratifying low- and high-risk groups allows for customized SSI prophylactic measures for patients in various risk categories and potentially enables future research targeted at high-risk patients.

Litter box preference in domestic cats: covered versus uncovered.

Feline inappropriate elimination (periuria and/or perichezia) remains a very common behavioral complaint of cat owners. Treatment recommendations often include improving the attractiveness of the litter boxes available to the cat. One frequent recommendation is to avoid covered litter boxes, although this has not previously been tested experimentally. The goal of this study was to assess whether, all else being equal, cats preferentially used uncovered litter boxes over covered litter boxes. Twenty-eight cats were enrolled in the study and offered the choice of a covered or uncovered box. Waste was scooped daily from each box, and the weight of waste in the different box styles was compared and evaluated using paired t-tests and χ(2) analyses. Overall, there was no significant difference between use of the two box styles. Eight individual cats did exhibit a preference (four for covered, four for uncovered), but individual preference results are not evenly distributed, with more cats than expected showing no preference between litter box types. We postulate that, if boxes are kept sufficiently clean (ie, once daily minimum cleaning), most cats will not show a preference for either box type. The observation that a minority of cats in the study exhibited a preference supports the recommendation of providing individual cats with a 'cafeteria' of litter box styles, including a covered box, to determine whether such a preference exists. These findings add to existing literature on the topic of feline inappropriate elimination and provide additional information for clinicians recommending treatment options for cats exhibiting this behavior.

The activity of primary motor cortex corticospinal neurons during tool use by macaque monkeys.

It has been suggested that the distinctive capacity of some nonhuman primates to use tools may reflect a well-developed corticospinal system and, in particular, direct cortico-motoneuronal (CM) connections to hand muscles. We investigated the activity of corticospinal neurons in the primary motor cortex hand area during the use of a tool by two adult macaque monkeys. They used a light rake to retrieve food rewards placed in their extrapersonal space. An analysis of EMG activity showed that the rake task involved a complex interaction of muscles acting on the digits, hand, and arm. Sixty-nine corticospinal neurons were identified antidromically as pyramidal tract neurons (PTNs). When tested on the rake task, most (64 of 69; 93%) showed a significant modulation of their discharge during at least one of three task periods: grasping the rake, projecting it beyond the food reward, and then pulling it back to retrieve the reward. Discharge patterns were heterogeneous, and many PTNs showed significant suppression of discharge during raking. Seventeen of the 69 PTNs recorded during the rake task were further identified as CM cells, exerting clear postspike facilitation on digit muscles, demonstrating that the CM system contributes to the skilled use of tools. We compared the activity of each PTN on the rake task with that during precision grip. Most PTNs (90%) modulated their activity significantly for both tasks, demonstrating that PTNs activated by a task involving fractionated movements of the digits are also recruited during rake use, although there were often contrasting patterns of PTN recruitment and muscle activity for the two tasks.

The effects of visual magnification and physical movement scale on the manipulation of a tool with indirect vision.

Modern tools often separate the visual and physical aspects of operation, requiring users to manipulate an instrument while viewing the results indirectly on a display. This can pose usability challenges particularly in applications, such as laparoscopic surgery, that require a high degree of movement precision. Magnification used to augment the view and, theoretically, enable finer movements, may introduce other visual-motor disruptions due to the apparent speed of the visual motion on screen (i.e., motion scaling). In this research, we sought to better understand the effects of visual magnification on human movement performance and control in operating a tool via indirect vision. Ten adult participants manipulated a computer mouse to direct a pointer to targets on a display. Results (Experiment 1) showed that, despite increased motion scaling, magnification of the view on screen enabled higher precision control of the mouse pointer. However, the relative effectiveness of visual magnification ultimately depended on the scale of the physical movement, and more specifically the precision limits of the whole-hand grip afforded by the mouse. When the physical scale of the hand/mouse movement was reduced (Experiment 2), fine-precision control began to reach its limits, even at full magnification. The role of magnification can thus be understood as "amplifying" the particular skill level afforded by the effecting limb. These findings suggest a fruitful area for future research is the optimization of hand-control interfaces of tools to maximize movement precision.

Effect of an odor eliminator on feline litter box behavior.

Decreasing litter box odor may be an important treatment component in addressing feline inappropriate elimination. A three-phase study was conducted to determine if the use of Zero Odor litter box spray increases the preference of litter boxes to cats, presumably by its odor-eliminating quality. In the first phase, cats were given a litter box preference test between a litter box sprayed with Zero Odor and one without. In the second phase, the number of occurrences of behaviors indicative of a cat's dissatisfaction with the litter box (scratching at the sides of the box, floor or wall, hesitating when entering the litter box, balancing on the side of the box and eliminating outside of the litter box) was compared before and after the use of Zero Odor. Last, the frequency of eliminations that occurred outside the litter box was measured during a baseline phase and a test phase, in which Zero Odor was sprayed into all litter boxes in the home. Significantly fewer behaviors associated with feline litter box dissatisfaction and fewer undesirable eliminations were observed in phases 2 and 3, respectively. These findings suggest that use of Zero Odor litter box spray appears to decrease litter box odor and increases the attractiveness of litter box to cats.