Cardiovascular images: pacemaker-lead fracture and excessive coiling in a dog.

A seven-year-old male castrated Labrador Retriever presented emergently due to concern for pacemaker malfunction five years after successful transvenous pacemaker implantation to treat partial atrial standstill. On presentation, the dog's pulse rate was 30-50 beats per minute. An electrocardiogram showed no spontaneous atrial activity or paced ventricular activity. Pacemaker interrogation revealed an increased impedance of 7557 ohms, indicating a lead malfunction. Thoracic radiographs confirmed the lead was fractured and had excessive coiling. The transvenous pacing system was turned off, left in place, and an epicardial pacing system was implanted the following day. The dog was discharged with no perioperative complications. The dog eventually required escalated medical therapy for progressive cardiac disease and was euthanized two years after implantation of the replacement pacemaker. This manuscript illustrates a complete lead fracture and excessive lead coiling, which has not previously been detailed in veterinary medicine.

[Unilateral mandibular fracture in horse - Treatment with fixateur externe, a complication during implant removal and procedure for removal of implant fragments]. / Unilaterale Mandibulafraktur bei einem Pferd.

The first part of this case report describes the surgical treatment of a unilateral mandibular fracture in the standing horse by using a fixateur type I. By the time of implant removal, the fracture had completely healed. However, during implant removal, an implant failure of 2 of the 4 implants occurred with fragments remaining in the bone. The second part of the report focuses on the development of a special surgical instrument that was designed for removal of the implant fragments. Furthermore, the surgical method allowing the entire extirpation of the fragments within a second surgery is described.According to the authors' knowledge, this is the first case report showing the use of the presented surgical technique for the treatment of a mandibular fracture in the standing horse. Additionally, this report also provides an approach for removing implant fragments from the depth of the bone which may occur in case of implant breakage as a potential complication of the described surgery.

Analysis of results from 21 years of milking system inspections in Japanese dairy farms.

To prevent mastitis caused by inappropriate milking systems, inspection of the system, and maintenance of optimal function are crucial. This study aimed to clarify the problems with milking systems in Japan by analyzing the results of milking system inspections over the past 21 years. A total of 190 dairy farms (358 systems; 153 high-line systems, 205 low-line systems) were inspected for the checkpoints of problems originating from installation (PI) or problems originating from insufficient maintenance (PIM). Results were divided into initial and periodic inspections, then analyzed by year of inspection or years elapsed since equipment installation. With increasing years, inadequacy of milk piping and regulator maintenance tended to increase for high-line systems. On the other hand, defects in milking units tended to increase for low-line systems. This difference was attributed to the structures of these milking systems. The present study revealed potential problem areas in high- and low-line milking systems from recent years. To maintain normal functioning in milking systems, the frequency and content of inspections as currently being conducted need to be reviewed.

Assessing the sharpness of hypodermic needles after repeated use.

Four gauges (14G, 16G, 18G, 20G) of single use hypodermic needles were evaluated for sharpness by measuring the force required to puncture rehydrated bovine leather. The needles began to dull after 1 use with maximum bluntness occurring within 4 to 5 uses.

Évaluation du tranchant des aiguilles hypodermiques après un usage répété. Quatre gabarits (14G, 16G, 18G, 20G) d'aiguilles hypodermiques à usage unique ont été évalués pour le tranchant en mesurant la force requise pour percer du cuir bovin réhydraté. Les aiguilles ont commencé à s'émousser après 1 usage et la capacité de tranchant maximale se produisait durant les 4 ou 5 premières utilisations.(Traduit par Isabelle Vallières).

Frequency of Undetected Glove Perforation and Associated Risk Factors in Equine Surgery.

OBJECTIVE: To estimate the frequency of undetected perforations in surgical gloves during equine surgery and to identify risk factors associated with occurrence. STUDY DESIGN: Observational cohort study. SAMPLE POPULATION: Surgical gloves-292 pairs. METHODS: Water leak tests were performed on gloves after equine surgery to detect perforations. Fifty pairs of unused gloves were also tested. Potential risk factors were recorded. Logistic regression was used to explore associations between putative risk factors and perforation. RESULTS: No perforations were detected in the unused gloves. Of 292 pairs of used gloves tested, 80 (27%) had at least one glove perforation per pair. The frequency of perforations was not different between surgery diplomates and residents (P=.69). The length and type of surgery were significantly associated with the likelihood of undetected glove perforation with surgeries longer than 60 minutes approximately 2.5 times more likely to result in glove perforation (P=.005). Surgery classified as soft tissue, orthopedic or exploratory celiotomy was 3 times more likely to result in glove perforation than minimally invasive surgery. The perforations occurred significantly more frequently in the nondominant hand (19%) than the dominant hand (11%) (P=.009). CONCLUSION: There is a high occurrence of undetected glove perforation in equine surgery. Precautions can be suggested based on this study although further investigation is required to assess whether glove perforations are associated with surgical site infections.

Iatrogenic embolization and transcatheter retrieval of a ventricular septal defect occluder in a dog.

A 7-month-old Irish Setter underwent transcatheter therapy of a muscular ventricular septal defect (VSD) and pulmonary valve stenosis. Standard devices for muscular VSD closure could not span the interventricular septum due to right ventricular hypertrophy, and an Amplatzer post-infarction muscular VSD occluder with a wider waist was successfully implanted. Following VSD closure, inflation of the balloon dilation catheter during balloon pulmonary valvuloplasty resulted in iatrogenic embolization of the VSD occluder to the left ventricular outflow tract. Retrieval and reimplantation of the device was achieved using a snare catheter. This report describes a potential complication and management during intracardiac device implantation in a dog. Additionally, the case illustrates that the Amplatzer post-infarction muscular VSD occluder holds potential value in animals with a hypertrophied interventricular septum that cannot be spanned using a conventional device.

Limited efficacy of Fever Tag(®) temperature sensing ear tags in calves with naturally occurring bovine respiratory disease or induced bovine viral diarrhea virus infection.

Temperature sensing ear tags were tested in 1) auction-derived calves with 50% incidence of bovine respiratory disease, and 2) specific pathogen-free calves infected with bovine virus diarrhea virus. There were no false positives, but tag placement, probe displacement, and a high threshold for activation all contributed to failure to reliably detect sick calves.

Efficacité limitée des étiquettes d'oreille Fever TagMDpour mesurer la température chez les veaux atteints de maladies respiratoires d'origine naturelle ou d'une infection induite par le virus de la diarrhée virale des bovins. Les étiquettes d'oreille pour mesurer la température ont été testées chez 1) des veaux provenant d'encans ayant 50 % d'incidence de maladies respiratoires et 2) des veaux exempts d'agents pathogènes spécifiques infectés par le virus de la diarrhée virale bovine. Il n'y avait aucun faux positif, mais le placement des étiquettes, le déplacement de la sonde et un seuil d'activation élevé ont tous contribué à l'échec de la détection fiable des veaux malades.(Traduit par Isabelle Vallières).

In vitro biomechanical comparison of 3.5 string of pearl plate fixation to 3.5 locking compression plate fixation in a canine fracture gap model.

OBJECTIVE: To compare the 3.5 string of pearls (SOP) plate with a 3.5 mm locking compression plate (LCP) using a fracture model in static loading and cyclic fatigue testing. STUDY DESIGN: In vitro biomechanical testing of paired tibias with a mid-diaphyseal ostectomy, stabilized by 1 of 2 locking systems. SAMPLE POPULATION: Cadaveric canine tibiae (n = 24 pairs). METHODS: Tibias were randomly divided into 4 equal groups: (1) 4-point bending single cycle to failure, (2) 4-point bending cyclic fatigue, (3) torsion single cycle to failure, and (4) torsion cyclic fatigue. Randomly assigned SOP and LCP bridged a 20 mm mid-diaphyseal ostectomy. Mean test variables values for each method were compared using a paired t-test within each group with significance set at P < .05. RESULTS: The SOP construct had significantly greater mean yield load, mean yield displacement, mean yield bending moment, mean composite rigidity and mean failure bending moment under static 4-point bending to failure than the LCP construct. Mean number of cycles to failure under 4-point bending was significantly greater for the SOP constructs but the mean number of cycles to failure in torsion was significantly greater for the LCP constructs. The LCP construct had significantly greater mean composite stiffness and significantly lesser mean displacement to yield and to failure in static torsion testing. CONCLUSION: The SOP construct was superior under bending static and cycling testing but the LCP construct was superior in static and cycling torsion testing.

Knot security and tensile strength of suture materials.

OBJECTIVE: To evaluate knot security and tensile failure load of suture tied in simple interrupted, beginning continuous, and ending continuous patterns for 11 suture materials commonly used in small animal surgery. STUDY DESIGN: Mechanical study. METHODS: For each of 11 suture material types, and 5 knot sizes (2, 3, 4, 5, and 6 throws) 2 surgeons each tied 6 knots (n = 12 for each knot size in 11 suture materials). Three types of patterns were evaluated: a simple interrupted square knot, a square knot beginning a simple continuous pattern, and the knot ending a simple continuous pattern. All knots were incubated in healthy canine donor plasma at 40°C for a minimum of 24 hours. Sutures were evaluated for knot security (knots untied, suture failed by breaking, suture slipped from the clamps, or suture untied before testing) and maximum load carried before knot slippage or knot failure (termed tensile failure load). RESULTS: Significant differences were found in knot security and tensile failure load among suture types. There was no significant difference between the simple interrupted knots and the knots at the beginning of a simple continuous pattern; however, both were significantly less likely to fail than the knots tied at the end of a simple continuous pattern. The number of throws per knot had a significant effect for knot security and tensile failure load. Surgeon experience had a significant effect on failure mode and tensile failure load. CONCLUSIONS: Suture type, number of throws per knot (knot size), suture pattern, and surgeon experience play an important role in knot security and should be considered when performing surgery.

In vitro evaluation of the torsional strength reduction of neonate calf metatarsal bones with Bicortical defects resulting from the removal of external fixation implants.

OBJECTIVE: To compare the torsional strength of calf metatarsal bones with defects produced by removal of 2 different implants. STUDY DESIGN: In vitro mechanical comparison of paired bones with bicortical defects resulting from the implantation of 2 different external fixation systems: the transfixation pin (TP) and the pin sleeve system (PS). SAMPLE POPULATION: Neonatal calf metatarsal bones (n = 6 pairs). METHODS: From each pair, 1 bone was surgically instrumented with 2 PS implants and the contralateral bone with 2 TP implants. Implants were removed immediately leaving bicortical defects at identical locations between paired metatarsi. Each bone was tested in torque until failure. The mechanical variables statistically compared were the torsional stiffness, the torque and angle at failure, and work to failure. RESULTS: For TP and PS constructs, respectively, there were no significant differences between construct types for any of the variables tested. Mean ± SD torsional stiffness: 5.50 ± 2.68 and 5.35 ± 1.79 (Nm/°), P = .75; torque: 57.42 ± 14.84 and 53.43 ± 10.16 (Nm); P = .34; angle at failure: 14.76 ± 4.33 and 15.45 ± 4.84 (°), P = .69; and work to failure 7.45 ± 3.19 and 8.89 ± 3.79 (J), P = .17). CONCLUSIONS: Bicortical defects resulting from the removal of PS and TP implants equally affect the investigated mechanical properties of neonate calf metatarsal bones.

Pacemaker malfunction due to mechanical failure of the lead-header interface.

An 8 year old female spayed Boxer dog, diagnosed with concurrent vasovagal syncope and arrhythmogenic right ventricular cardiomyopathy, presented for routine evaluation approximately three months following epicardial pacemaker implantation. Routine device interrogation revealed intermittent loss of ventricular capture and intermittent failure to appropriately sense. Following evaluation of chronic impedance data, failure of the pacemaker lead-header interface or lead conductor fracture was suspected. Radiographic and pacemaker interrogator findings suggested incomplete lead insertion into the device header with intermittent loss of ventricular capture and variable pacemaker sensing. We hypothesize that either the presence of a loose or cross-threaded set screw or operator error at the time of device implantation may have caused this complication. This report details the diagnosis of mechanical failure of the lead-header interface, a complication not previously reported in a veterinary patient.

Comparison of noncontact infrared thermometry and 3 commercial subcutaneous temperature transponding microchips with rectal thermometry in rhesus macaques (Macaca mulatta).

This study compared a noncontact infrared laser thermometer and 3 different brands of subcutaneous temperature transponding microchips with rectal thermometry in 50 rhesus macaques (Macaca mulatta). The data were analyzed by using intraclass correlation coefficients and limits of agreement. In addition, the technical capabilities and practicality of the thermometers in the clinical setting were reviewed. None of the alternative techniques investigated was equivalent to rectal thermometry in rhesus macaques. Temperatures obtained by using microchips had higher correlation and agreed more closely with rectal temperatures than did those obtained by the noncontact infrared method. However, transponding microchips did not yield consistent results. Due to difficulty in positioning nonsedated macaques in their homecage, subcutaneous microchips were not practical in the clinical setting. Furthermore, pair-housed macaques may be able to break or remove microchips from their cagemates.