Development of a simple method to measure static body weight distribution in 1 neurologically normal small breed dogs

24 Background: Objective outcome measures capable of tracking different aspects of 25 functional recovery in dogs with acute intervertebral disc herniation are needed to 26 optimize physical rehabilitation protocols. Normal, pre-injury distribution of body weight 27 in this population is unknown. The aims of this study were to quantify static weight 28 distribution (SWD) using digital scales and to establish the feasibility of different scale 29 methods in neurologically normal, chondrodystrophic small breed dogs predisposed to 30 intervertebral disc herniation. 31 32 Results: Twenty-five healthy dogs were enrolled with a mean age of 4.6 years (SD 2.7) 33 and a mean total body weight of 11.5 kg (SD 3.6). SWD for the thoracic and pelvic limbs 34 and between individual limbs was acquired in triplicate and expressed as a percentage 35 of total body weight using commercially available digital scales in four combinations: two 36 bathroom, two kitchen (with thoracic and pelvic limbs combined), four bathroom and 37 four kitchen (with limbs measured individually). SWD was also obtained using a 38 pressure sensing walkway for comparison to scale data. Feasibility for each method 39 was determined and coefficients of variation were used to calculate inter-trial variability. 40 Mean SWD values were compared between methods using an ANOVA. The two 41 bathroom scales method had the highest feasibility and lowest inter-trial variability and 42 resulted in mean thoracic and pelvic limb SWD of 63% (SD 3%) and 37% (SD 3%), 43 respectively. Thoracic limb mean SWD was higher for the PSW compared to any of the 44 scale methods (p<0.0001). 45 Conclusions: SWD in a population of healthy chondrodystrophic dogs was simple to 47 obtain using inexpensive and readily available digital scales. This study generated SWD 48 data for subsequent comparison to dogs recovering from acute intervertebral disc herniation. We developed a simple, objective method to quantify SWD in neurologically normal 300 chrondrodystrophic small breed dogs. Using readily available and inexpensive digital 301 scales, we demonstrated that measurement of thoracic to pelvic limb SWD is feasible, 302 practical and can be easily implemented in any clinical setting. These results provide 303 the foundation to compare to neurologically abnormal dogs recovering from acute 304 thoracolumbar IVDH and to continue to develop this technique as an objective outcome 305 measure for use in dogs rehabilitating from SCI.

prevented acquiring data. Using the B4 method was not possible in smaller dogs (< 8.4 155 kg) due to values not registering for individual limbs (below the 1.4kg limit of detection).

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The K2 and K4 methods were not possible in larger dogs (> 8.6kg, > 13.1kg, 157 respectively) due to exceeding the upper weight range reported for these scales (5kg).

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Variability across trials for each scale method is presented in Table 2. The B2 and K2 159 methods were more reliable compared to B4 and K4 methods. Using the two scale methods, coefficients of variation for thoracic and pelvic limb measurements between 161 trials were less than 10%. With the four scale methods, inter-trial variability in 162 measurements for each individual limb was greater and ranged from 9 to 21%. Mean thoracic to pelvic limb SWD for each method is depicted in Figure 1. Across the 166 scale methods, the mean SWD for the thoracic limbs ranged from 59-63% (SD 3.0-167 4.0%) and the pelvic limbs ranged from 37-41% (SD 3.0-4.5%). Mean thoracic and 168 pelvic limb SWD for the PSW were 68% (SD 4.0%) and 32% (SD 4.0%), respectively.

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The thoracic limb SWD was significantly higher for values obtained on the PSW Our results demonstrate that SWD was feasible to obtain using commercially available 186 digital scales in a population of neurologically normal dogs ranging from 5 to 20 187 kilograms in BW. Using two digital bathroom scales (B2) was the simplest and most 188 reliable technique, and resulted in a thoracic limb to pelvic limb SWD of 63% to 37%.

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The other scale methods might be useful in specific scenarios such as using the kitchen

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We recruited dogs that were amenable to handling and, therefore, encountered only a 206 single dog in which measurements were limited by a behavioral issue (measurements were initially obtained easily but the dog tired of the handling and became aggressive).

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To facilitate cooperation and tolerance, we allowed all dogs several minutes to 209 acclimate to the procedures and to having their limbs manipulated before starting to 210 collect measurements and took breaks as needed. It is possible that behavioral issues 211 will be more apparent in dogs that might be painful secondary to IVDH or surgery.

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The SWD data obtained in this population of normal dogs will allow for subsequent 274 comparison to dogs recovering from IVDH, the most common cause of acute thoracolumbar SCI in dogs. 25 While it has been reported that more than half of

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Feasibility scores were generated for each stance trial for each combination of scales.

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A feasibility score of 1 was defined as standing appropriately for at least three seconds 358 during data acquisition. A feasibility score of 0 was designated for dogs unable or 359 unwilling to stand squarely for three seconds or when the scale was unable to register a 360 numeric value. If a feasibility score of 1 was obtained for three trials, the method was 361 considered feasible in that dog. If a feasibility score of 1 was not obtained in three 362 separate trials, data from that scale combination was excluded from further analysis for