Ex vivo evaluation of novel core tenorrhaphy patterns in dogs.

OBJECTIVE: To compare the biomechanical properties and gapping characteristics of four novel tenorrhaphy patterns in a canine flexor tendon model. STUDY DESIGN: Ex vivo, randomized, biomechanical study. SAMPLE POPULATION: Superficial digital flexor tendons of 60 forelimbs (30 dogs). METHODS: Each tendon was transected 25 mm distal to its musculotendinous junction prior to tenorrhaphy with 2-0 polypropylene. Repair patterns included the three-loop pulley (3LP, control), exposed double-cross-lock (ExDCrL), embedded double-cross-lock (EmDCrL), triple-circle-lock (TCiL), and Modified-Tang patterns (MTang) were randomly assigned to each experimental group (n = 12/group). Yield, peak, and failure loads, gap formation and failure modes were compared. RESULTS: Tendons repaired with ExDCrL (p < .0001), EmDCrL (p < .0001), and MTang (p < .0001) sustained yield, peak, and failure loads ~2.2x, ~2.0x, and ~1.9x, respectively, greater than those repaired with 3LP. Loads to 1 and 3 mm gapping were also higher for ExDCrL (p < .0001), EmDCrL (p < .0004), and MTang constructs (p < .0017) compared to 3LP. Although TCiL constructs sustained higher loads, their resistance to gap formation did not differ from that of 3LP repairs. Failure mode differed between groups (p < .0001), EmDCrL, ExDCrL, MTang, and TCiL constructs failing predominantly by suture breakage compared to 3LP repairs that failed by suture pull-through. CONCLUSION: Use of novel patterns ExDCrL, EmDCrL, and MTang improved resistance to loads and gap formation and were biomechanically superior compared to 3LP in healthy canine tendon repairs. CLINICAL SIGNIFICANCE: These results justify in vivo evaluation of ExDCrL, EmDCrL, or MTang pattern for tenorrhaphy in dogs.

Serum artemin is not correlated with sensitivity within dogs with naturally occurring osteoarthritis pain.

Osteoarthritis (OA) pain is associated with peripheral and central sensitization in humans and results in widespread increased sensitivity across the body. Sensitization contributes to the OA-associated pain (OAP) state. We recently identified increased levels of an endogenous neurotrophic factor, artemin (ARTN), in dogs with OAP compared to healthy pain-free controls. Circulating ARTN released from damaged tissues in OA, may play a central role in widespread sensitivity and pain. However, the relationship between ARTN and somatosensory sensitivity remains unknown. The study aimed to assess the relationship between serum ARTN concentrations and measures of sensitivity in dogs with OAP using quantitative sensory testing. We hypothesized that there would be a positive association between circulating ARTN and increased sensitivity to mechanical and thermal stimuli in dogs with OAP. We used linear and logistic regression models to assess the relationship between ARTN, sensitization, and pain within a cohort of 43 dogs with spontaneous OAP. Serum ARTN was not associated with the degree of sensitization within dogs with OAP. Further, across dogs with varying OAP severity, we did not find any association between ARTN, and clinical measures of joint pain and disability. Although a relationship between ARTN and joint pain was not ruled out.

A randomized, prospective, comparative trial of a variable-angle versus fixed-angle endoscope for exploratory thoracoscopy in canine cadavers.

OBJECTIVE: To compare the efficacy of a variable-angle endoscope (VAE) for canine thoracoscopic exploration to a traditional fixed-angle endoscope (FAE). STUDY DESIGN: Randomized, prospective, comparative study. SAMPLE POPULATION: Five fresh canine cadavers. METHODS: Twelve predetermined anatomical locations were labeled after median sternotomy in each cadaveric thorax. Two board-certified veterinary surgeons performed thoracoscopic evaluation of each thorax using a fixed-angle (30°) and a variable-angle (0°-120°) endoscope with and without lungs mechanically ventilated. The order of surgeon, lung ventilation, and endoscope were determined using a randomized block design. Time to visualize each anatomical location was compared for surgeon, endoscope, and lung ventilation status. Primary outcome measures were time to individual anatomical location, total simulated thoracoscopic exploration time, and ability to identify anatomical location within the designated time period. RESULTS: Lung ventilation (difference = 184 seconds, P = .015, 95% CI = 45-342 seconds) and endoscope type (difference = 112 seconds, P = .029; 95% CI = 10-213 seconds) had an effect on the cumulative time for complete thoracoscopic exploration. The VAE shortened the time to identify three of the 12 anatomical locations when controlling for the effects of lung ventilation. Use of the VAE did not improve time to identification for any locations compared to the FAE when lungs were not ventilated. The VAE facilitated significantly shorter cumulative thoracoscopic exploration time compared with the FAE. Failure to identify predetermined locations was more common with the FAE than with the VAE. CONCLUSION: Use of a rigid VAE decreased cumulative thoracoscopic exploration time and provided an alternative to one-lung ventilation for circumventing the visual impediments of lung ventilation. CLINICAL SIGNIFICANCE: This cadaveric study provides evidence that one-lung ventilation and use of a VAE may improve surgeon efficiency during exploratory thoracoscopy.

The effect of spontaneous osteoarthritis on conditioned pain modulation in the canine model.

Endogenous Pain Modulation (EPM) impairment is a significant contributor to chronic pain. Conditioned pain modulation (CPM) testing assesses EPM function. Osteoarthritic (OA) dogs are good translational models, but CPM has not been explored. Our aim was to assess EPM impairment in OA dogs compared to controls using CPM. We hypothesized that CPM testing would demonstrate EPM impairment in OA dogs compared to controls. Dogs with stifle/hip OA and demographically-matched controls were recruited. The pre-conditioning test stimulus, using mechanical/thermal quantitative sensory testing (MQST or TQST), were performed at the metatarsus. A 22N blunt probe (conditioning stimulus) was applied to the contralateral antebrachium for 2 minutes, followed by MQST or TQST (post-conditioning test stimulus). The threshold changes from pre to post-conditioning (∆MQST and ∆TQST) were compared between OA and control dogs. Twenty-four client-owned dogs (OA, n = 11; controls, n = 13) were recruited. The ∆MQST(p < 0.001) and ∆TQST(p < 0.001) increased in control dogs but not OA dogs (∆MQST p = 0.65; ∆TQST p = 0.76). Both ∆MQST(p < 0.001) and ∆TQST(p < 0.001) were different between the OA and control groups. These are the first data showing that EPM impairment is associated with canine OA pain. The spontaneous OA dog model may be used to test drugs that normalize EPM function.

Influence of fixation systems on complications after tibial plateau leveling osteotomy in dogs greater than 45.4 kilograms (100 lb).

OBJECTIVE: To determine the influence of 3 fixation systems on complications rate after tibial plateau leveling osteotomy (TPLO) in dogs >45.4 kg. STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Dogs (N = 287, 342 stifles) >45.4 kg with cranial cruciate ligament tear treated with TPLO. METHODS: The medical records of dogs treated with TPLO were reviewed for fixation and postoperative complications, with a follow-up of at least 6 weeks. A random effects logistic regression model was used to evaluate the association between the type of TPLO fixation system and complications. RESULTS: The fixation systems included a 3.5-mm broad TPLO plate alone (8P; 78.4%), a 3.5-mm broad TPLO plate with SOP (String of Pearls) plate (8AP; 14.9%), and a 3.5-mm standard TPLO plate (6P; 6.7%). Among the included stifles, 214 (62.6%) fixation systems were classified as locking, and 128 (37.4%) were classified as nonlocking. The fixation system was predictive of complications. The 8P had the lowest odds ratio for complication among the 3 fixation systems. Odds of developing complications were higher with the 8AP fixation system than with the 8P fixation system. Locking fixation eliminated the association between weight and complication rate. CONCLUSION: Fixation of a TPLO with the 8AP increased the risk of complications compared with the 8P in this population of large dogs. CLINICAL SIGNIFICANCE: Locking fixation of TPLO with a 3.5-mm broad TPLO plate alone should be considered in large dogs because it may reduce complications.