In vitro evaluation of a hybrid negative pressure system for wound therapy.

OBJECTIVE: The objective of this study was to assess whether negative pressure could be maintained accurately and repeatably with a wall-suction-based hybrid negative pressure wound therapy (h-NPWT) system by comparing it with a commercial negative pressure wound therapy (NPWT) device. STUDY DESIGN: In vitro experimental study. METHODS: A commercial NPWT device (control) and three h-NPWT devices, with 0, 3, and 6 meters of additional tubing using the hospital-wall suction (groups 1, 2, and 3 respectively), were applied sequentially to a commercial NPWT dressing on a silicone skin substrate and set to run at a continuous pressure of -125 mmHg. The pressure within the wound space was monitored at 10 second intervals for 24 h. The process was repeated five times for each group. RESULTS: The commercial NPWT device produced an average pressure variance of 3.02 mmHg, and the h-NPWT produced average variances of 4.38, 4.24 and 4.20 mmHg for groups 1, 2 and 3, respectively. All groups produced an average pressure within 0.15 mmHg of -125 mmHg over the 24-hour period, and the h-NPWT systems produced the smallest range with all values remaining within a ±5% variation from -125 mmHg. CONCLUSION: The h-NPWT system achieved negative pressures that were comparable to those of a commercial control NPWT device. The addition of tubing between the skin substrate and the canister did not affect the pressure applied at the wound site. CLINICAL SIGNIFICANCE: The h-NPWT device tested in this study can be considered as an alternative for negative wound therapy when a commercial device cannot be used.

Safety evaluation of the Guardian device on the common carotid artery in sheep.

Background: Pulse pressure intensity in middle-aged adults is a risk factor for dementia. The Guardian device (The Brain Protection Company, Sydney, Australia) has been developed to reduce pulse pressure, as a potential therapy. Objectives: The aim of this study was to evaluate the safety of the Guardian, a novel pulse modulation device designed to reduce the intensity of the pulse pressure that penetrates into the cerebral small vessels. The Guardian is a helix that gently wraps around the common carotid artery (CCA) to slightly change its shape, to absorb pulsatility, without lowering flow. Methods: The Guardian was implanted bilaterally on the CCAs of 10 mature sheep for chronic implant periods of 3, 6 or 8 months. The ratio of internal device diameter to outer diameter of the CCA varied from 63% to 92% (n = 20). The implant position on the vessel was marked surgically at implant. Gross pathology and histopathology of the CCA were examined at 3- and 6-months post explant. Most devices were explanted using open surgery, however minimally invasive surgical explant techniques were examined in 2 animals to assess the potential of this approach for explant in humans if required. Results: The Guardian was successfully implanted with no adverse events, and minimally invasive explant appeared to be viable for removal. Following implant, the device was surrounded by a thin fibrous capsule, with similar pathology at 3- and 6-months. Minimal or no movement was observed. CCA sections appeared histologically normal, with no evidence of thrombosis, stenosis, fibrosis, chronic inflammatory response, or vessel degeneration. Conclusions: The feasibility of surgical implantation and biomaterial safety of the Guardian was confirmed over 8 months. Minimally invasive explant of the Guardian has the potential to be viable. Further work is required to demonstrate efficacy in vitro and/or in vivo before evaluation in humans.

The development of a systematic ultrasound protocol facilitates the visualization of foreign bodies within the canine distal limb.

Ultrasonography is an excellent investigative tool that can assist with the diagnosis of soft tissue conditions. In human medicine, ultrasonography is a fundamental diagnostic tool for the investigation of suspected vegetal foreign bodies (VFB), with protocol-based ultrasonography providing increased accuracy compared to lesion-focused examinations. Protocol-based ultrasonography is an emerging tool within the veterinary field, however, compared to human medicine is not routinely employed. The objective of this study was to develop a systematic ultrasound protocol to examine the distal limb for the visualization of vegetal foreign bodies (SUEDVEG). A 12 MHz linear and an 18 MHz high-frequency small-footprint linear array transducer was used on cadaver forelimbs (n = 6) and hindlimbs (n = 6) with images obtained from three common foreign body locations within the distal limb; 1; the interdigital webbing, 2; the palmar/plantar aspect of the phalanges and metacarpus and 3; the dorsal region of the phalanges and metacarpus. From these images, a 13-step systematic musculoskeletal protocol was developed and utilized on eight clinical cases or 10 limbs that had signs typical of distal limb VFB to preliminarily validate the proposed method. Vegetal foreign bodies were successfully identified and retrieved in seven (n = 8) clinical cases with method steps 9 and 11 (orthogonal views) identifying the majority of VFBs. The described ultrasound method appears highly useful for visualizing soft tissue locations of the canine distal limb known for tracking foreign bodies. Further studies are required to validate the described systematic examination method as the preferred clinical protocol over currently used lesion-focused exploration techniques.

Retrospective Comparison of Titanium Hybrid Locking Plate with Stainless Steel Hybrid Dynamic Compression Plate for Pancarpal Arthrodesis: 23 Dogs.

OBJECTIVE: The aim of this study was to evaluate outcomes and complications of dogs that had pancarpal arthrodesis (PCA) using a titanium hybrid advanced locking plate system (ALPS) and stainless steel hybrid dynamic compression plate (HDCP). STUDY DESIGN: Retrospective observational study. METHODS: Medical records (2007-2020) were reviewed for cases that had PCA performed using ALPS or HDCP. Implant characteristics including metacarpal coverage (MCov), metacarpal width occupied by screw diameter percentage and carpal arthrodesis angle (CAA), complications and outcomes were recorded. RESULTS: Pancarpal arthrodesis was performed with ALPS on 15 limbs from 12 dogs, and HDCP on 14 limbs from 11dogs. Median follow-up time was 1,157 days (range: 62-1,902 days) for ALPS group and 340 days (range: 43-1,465 days) for HDCP. Median MCov for ALPS group was 74% (range: 60-87.5%) compared with 56.5% (range: 49.7-91.3%) for HDCP (p = 0.001). There was no difference in CAA and metacarpal width to screw diameter percentage between ALPS and HDCP group. Major and minor complications and surgical site infection rates were not statistically different between the two groups. Plate fracture occurred in 2/15 ALPS PCA and screw loosening occurred in 4/14 HDCP PCA. Full function was achieved in 8/12 and 8/11 of ALPS and HDCP cases, respectively, which was not statistically different (p = 0.76). CONCLUSION: The use of ALPS offers comparable performance to HDCP for PCA.

Single Pedicle Advancement Flap Models for Teaching Veterinary Reconstructive Surgical Techniques.

Reconstructive surgical techniques are used in both general and referral veterinary practice to facilitate closure of challenging wound defects. During veterinary studies, there are often limited opportunities for students to practice these techniques on live patients or cadavers. Surgical models, including suture pads and ovariohysterectomy models, have been successfully incorporated into veterinary teaching, providing students with additional practice. Models to simulate veterinary reconstructive surgical techniques are lacking. In the current study, a single pedicle advancement flap model was designed. The design consisted of a silicone model secured by a plate, providing tension. Fifth-year veterinary science students (n = 34) were surveyed to assess the model's impact on surgical technique and confidence. Students were also assessed to determine surgical technique using the models. It was hypothesized that students who had two additional practice sessions using the models (Trial group, n = 17) would show greater improvement in technique than students who had no practice sessions between assessments (Control group, n = 17). Students strongly agreed (median score 5/5) that using the model helped to reinforce the subdermal plexus flap technique and improved their confidence in performing a subdermal plexus flap. Students from both groups performed significantly better in the follow-up assessment compared to the initial assessment. No significantly greater improvement was observed in technique between the control and the trial groups. Results suggest that the students' reconstructive surgical technique improved after a single practice session and that the single pedicle advancement flap model can be used synergistically with other teaching methods.

Ex vivo comparison of standing and recumbent repair of incomplete parasagittal fractures of the first phalanx in horses.

OBJECTIVE: To assess suspensory ligament extensor branch location and fracture gap reduction with simulation of standing and recumbent cortical bone screw repair of experimental incomplete parasagittal proximal phalanx (P1) fractures. STUDY DESIGN: Controlled laboratory study. SAMPLE POPULATION: Twenty equine cadaver forelimbs. METHODS: Simulated fractures were repaired twice in random order. A proximal cortical bone screw was placed in lag fashion with the limb unloaded (simulated recumbent repair) and loaded to 38% of body weight (range, 375-568 kg; simulated standing repair). Changes in fracture gap width were assessed on computed tomography (CT) images and with intraplanar force-sensitive resistors measuring voltage ratios (V△ ) between loaded recumbent (R-1) and standing repair simulations (R-2). Extensor branch borders were determined relative to implant position and sagittal P1 width on transverse CT images. P ≤ .05 was considered significant. RESULTS: Standing repair simulation-associated fracture gaps were not wider than in R-1 while controlling for confounding factors (loading weight, implant position, or animal age; P > .7, repeated-measures analysis of variance). Voltage ratio data associated with R-2 were not smaller than with R-1 (mean difference, 0.002 ± 0.052; one-sided Wilcoxon signed-rank test, P = .27). More of P1 width was approachable palmar to extensor branches when limbs were loaded (0.804 ± 0.314 cm) vs unloaded (0.651 ± 0.31 cm; paired Student's t test, P < .001). CONCLUSION: Simulated standing repair was not associated with inferior fracture reduction compared with loaded simulations of recumbent repairs. Limb loading affected extensor branch location relevant to implant positioning. CLINICAL SIGNIFICANCE: Unloading during standing repair of incomplete parasagittal proximal P1 fractures may not be required to optimize fracture reduction.

The common carotid artery provides significant pressure wave dampening in the young adult sheep.

BACKGROUND: It has been established that the central elastic arteries of the mammalian circulation dampen the high pulse pressure emanating from the left ventricle, so that the pulsations in distal arterioles, such as in the cerebral circulation, are of lower amplitude than more centrally. However, the contribution of the common carotid artery (CCA) to protection of the cerebral microvasculature from high pulse pressure is not known, specifically to what extent viscoelastic energy dissipation in the arterial wall might contribute to the shock absorbing function of the large conduit arteries. METHODS: Young adult sheep (n = 6) were anaesthetised and their CCAs (n = 7) exposed. Pressure catheters were inserted 10-15 cm apart, proximally and distally in the CCA; a flow probe was placed proximally on the vessel. RESULTS: The median dp/dtmax on the pressure rise of the arterial wave upstroke for the proximal CCA was 619 mm Hg/s and for the distal CCA it was significantly lower, at 197 mm Hg/s (p = 0.0156; n = 7). The median pulse pressure of the proximal CCA was 24 mm Hg/s; distal pulse pressure was significantly lower, at 18 mm Hg/s (p = 0.0156; n = 7). The median flow rate was 0.97 L/min with an interquartile range from 0.51 to 1.15 L/min. CONCLUSIONS: The native CCA in the young adult sheep is an effective "pressure dampener" in the arterial circulation, reducing both pressure slope and pulse pressure, most likely via viscous dampening in the arterial wall.

In vitro comparison of linear vs triangular screw configuration to stabilize complete uniarticular parasagittal fractures of the proximal phalanx in horses.

OBJECTIVE: To assess fracture gap reduction and stability of linear vs triangular 4.5-mm lag screw repair of experimental, uniarticular, and complete forelimb proximal phalanx (P1) fractures. STUDY DESIGN: Experimental. SAMPLE POPULATION: Fourteen equine cadaver limbs/horses. METHODS: Simulated fractures were repaired with 2 lag screws under 4-Nm insertion torque (linear repair). Computed tomography (CT) imaging was performed with the leg unloaded and loaded to forces generated while walking. The fracture repair was revised to include 3 lag screws placed with the same insertion torque (triangular repair) prior to CT. The width of the fracture gap was assessed qualitatively by 2 observers and graded on the basis of gap measurements relative to the average voxel size at dorsal, mid, and palmar P1 sites. Interobserver agreement was assessed with Cohen's κ. The effect of repair type, loading condition, and measurement site on fracture gap grades was evaluated by using Kendall's τ-b correlation coefficients and paired nonparametric tests. Significance was set at P ≤ .05. RESULTS: Agreement between loading and fracture gap widening was fair in triangular (κ = 0.53) and excellent in linear (κ = 0.81) repairs. Loading resulted in fracture gap distraction in linear repairs (Plinear = .008). Triangular repairs reduced fractures better irrespective of loading (Punloaded = .003; Ploaded < .001). The type of repair was not correlated with fracture gap grades at unloaded mid and loaded dorsal P1 sites. CONCLUSION: Repair of uniarticular complete parasagittal fractures with a triangular screw configuration improved in vitro fracture gap reduction and stability. CLINICAL SIGNIFICANCE: Triangular lag screw repair likely improves biomechanical conditions during postoperative weight bearing.

Effect of Metoclopramide on the Incidence of Early Postoperative Aspiration Pneumonia in Dogs with Acquired Idiopathic Laryngeal Paralysis.

OBJECTIVE: Evaluate the effect of a perioperative intravenous continuous rate infusion (CRI) of metoclopramide on the incidence of aspiration pneumonia in the short term postoperative period in dogs undergoing unilateral arytenoid lateralization. STUDY DESIGN: Prospective, randomized, multi-center clinical trial. ANIMALS: 61 client-owned dogs with idiopathic laryngeal paralysis and normal preoperative thoracic radiographs. METHODS: All dogs underwent unilateral arytenoid lateralization with a uniform anesthetic, analgesic, and management protocol. Dogs in the treatment group received an intravenous CRI of metoclopramide for 24 hours perioperative. All dogs were assessed for clinical signs of aspiration pneumonia based on the results of physical examination and owner interview up to the point of suture removal (10-14 days postoperative). Any dog with suspected aspiration pneumonia had thoracic radiographs performed. RESULTS: Six dogs developed aspiration pneumonia in the short term postoperative period (2/28 control dogs and 4/33 treated dogs), accounting for an overall frequency of 10% with no significant difference between control and treated dogs. No variables measured in the study were significantly different between control and treated dogs. CONCLUSIONS: Perioperative metoclopramide, at the doses used in this study, did not affect the incidence of aspiration pneumonia in the short term postoperative period in dogs with idiopathic laryngeal paralysis undergoing unilateral arytenoid lateralization.

Management of bilateral idiopathic renal hematuria in a dog with silver nitrate.

Renal hematuria has limited treatment options. This report describes management of bilateral idiopathic renal hematuria in a dog with surgically assisted installation of 0.5% silver nitrate solution. Initial treatment resulted in freedom from clinical signs or recurrent anemia for 10 months; however, recurrence of bleeding following a nephrectomy resulted in euthanasia.

Gestion de l'hématurie rénale idiopathique bilatérale chez un chien à l'aide du nitrate d'argent. L'hématurie rénale offre des options de traitement limitées. Ce rapport décrit la gestion de l'hématurie rénale idiopathique bilatérale chez un chien à l'aide de l'installation assistée par chirurgie d'une solution de nitrate d'argent de 0,5 %. Le traitement initial a produit une disparition des signes cliniques ou de l'anémie récurrente pendant 10 mois. Cependant, la récurrence des saignements après une néphrectomie se sont traduits par l'euthanasie.(Traduit par Isabelle Vallières).

Evaluation of postceliotomy peritoneal drain fluid volume, cytology, and blood-to-peritoneal fluid lactate and glucose differences in normal dogs.

OBJECTIVE: To describe peritoneal drain fluid volume, fluid cytology, and blood-to-peritoneal fluid lactate and glucose concentration differences after exploratory celiotomy in normal dogs. STUDY DESIGN: Prospective study. ANIMALS: Healthy Beagle dogs (n=10). METHODS: After exploratory celiotomy, a peritoneal drain was placed, and peritoneal fluid was recorded every 6 hours for 7 days. Fluid was submitted for cytologic examination, and fluid and blood glucose and lactate concentrations were recorded every 12 hours. On day 7, drains were removed and drain tips submitted for aerobic bacterial culture. RESULTS: Mean peritoneal fluid volume decreased from 2.8 mL/kg/day (day 1) to 0.6 mL/kg/day (day 7). All dogs had degenerate neutrophils in peritoneal fluid throughout the 7 days. Four dogs developed contaminated drains. Blood-to-peritoneal glucose concentration differences > 20 mg/dL occurred after day 4. By day 7, 5 of 7 dogs with patent drains had blood-to-peritoneal lactate concentration differences < -2 mmol/L. CONCLUSION: After day 4, blood-to-peritoneal glucose concentration differences were consistent with septic effusion based on previously reported values used to diagnose septic peritonitis in dogs. Blood-to-peritoneal lactate concentration differences varied but after day 4, >70% of dogs had differences consistent with septic peritonitis each day. Postoperative blood-to-peritoneal fluid glucose and lactate difference may not be reliable indicators of septic peritonitis when evaluating abdominal fluid collected with closed suction drains.