Dog Cadavers Research Articles

Aberrant arrangement of the musculocutaneous and median nerves in the thoracic limbs of a mixed-breed dog cadaver.

In the left thoracic limb of a male cadaver (adult mixed-breed dog), the median nerve (MN) after departing from the common median/ulnar nerve (UN) trunk received two branches. One from the lateral thoracic nerve (LTN) and the other from the musculocutaneous nerve (MCN). These both passed cranial to the axillary artery at the level of the lateral thoracic artery and joined the median nerve. Thus, in the proximal brachium, the axillary artery was cradled by this union, similar to the ansa axillaris of large animals and similar formations reported in human and non-human primates. In the distal brachium, the communicating branch ran unusually from the MN to the MCN on the left, and in both directions on the right. Awareness of such anatomical variations of the terminal branches of the brachial plexus (BP) in addition to the embryonic and evolutionary aspects can be useful in explaining neuroarterial signs with unknown origin, as those reported in human medicine.

Robot-assisted radical prostatectomy training: Description of a canine cadaveric model.

Assess the relevance of a canine model in robot-assisted radical prostatectomy (RARP) training. Step-by-step RARP was performed in five dog cadavers using a Da Vinci Si® Surgical Robot (Intuitive Surgical, Inc.). The steps were defined according to the RARP score, a validated training tool describing 17 key steps and four levels of difficulty; each step was scored to reflect the anatomical and technical similarities, realism of dissection, and face validity of the canine model compared to the human procedure. Fourteen steps were performed during each procedure. Face validity was scored as high or very high for five of the nine steps of difficulty levels 1 and 2 as well as five of the eight steps of difficulty levels 3 and 4, especially nerve preservation, vesicourethral anastomosis and lymph node dissection. The cadaveric canine model seems to be a realistic and relevant training model for key steps of RARP.

Age estimation in young dogs by radiographic assessment of the canine pulp cavity/tooth width ratio.

Age estimation in adult dogs can be performed by the radiographic measurement of the tooth pulp cavity, but the technique has hardly been described. In this study, the application of measuring pulp/tooth width ratios (P/T ratios) of the maxillary canine teeth was investigated. Pulp and tooth widths were measured at two locations on 166maxillary canine teeth of the heads of 84 dog cadavers, using digital extraoral lateral oblique open mouth radiographs. The dogs belonged to different breeds and sexes and had a known age between 194 and 1907days (approximately 6months - 5years). Both at the cemento-enamel junction (CE) and the half-height of the tooth, a comparable non-linear regression with age was demonstrated. Measuring at the CE location was less hindered by wear or superimposition. No statistically significant difference according to sex and breed size and no clinically significant difference according to skull type was found. The highest predictable capacity was found in the youngest dogs until the age of 448days, of which 84.4% of the canine teeth had a P/T ratio above 0.39. Our results demonstrate that measuring P/T ratios of canine teeth can be used in practice to assign dogs to age categories, with the highest accuracy in young adult dogs.

Novel surgical approach to neoplastic lesions in the distal part of the urethra: A pilot cadaver study comparing open and hybrid techniques.

Tumours of the distal urethra in female dogs are often difficult to treat, and the surgical methods described thus far have technical limitations. This study aimed to present a novel approach to the surgical treatment of distal urethral tumours. This study used dog cadavers to evaluate the technical feasibility of surgically removing neoplastic lesions in the distal urethra and compared surgical outcomes of open surgery with those of hybrid surgery (combination of laparoscopy and open surgery). Open intact, open spayed, hybrid intact, and hybrid spayed dog cadaver groups underwent surgery (n = 6 per group). The novel surgical method was based on vulvovaginectomy (ovariohysterectomy in intact dogs), resection of the distal part of the urethra, and pre‐pubic urethrostomy. Outcomes of interest included technical feasibility of each procedure, using both surgical techniques, wound length, time required to complete the procedure, and the incidence of intraoperative ureter and rectum injuries. Surgical technique and reproductive status affected operating time. Technique choice affected wound length; the surgical wound was longer in the open group than in the hybrid group. Macroscopic evaluation of the rectum did not reveal any damage to the wall. There was no evidence of ureter leakage or obstruction in any case. The present findings suggest that both open and hybrid surgery can be used to treat distal urethral tumours.

An anatomical training model for cerebrospinal liquid collection and myelography in embalmed dog cadavers

An anatomical training model for cerebrospinal liquid collection and myelography in embalmed dog cadavers

Evaluation of minimally invasive surgical reduction of sacroiliac luxation in toy breed dogs: a cadaver study

BackgroundMinimally invasive surgery (MIS) technique of sacroiliac luxation in toy breed dogs using cannulated screws has not been described.ObjectivesThe purpose of this study was to evaluate the effectiveness of pelvic canal recovery, the reproducibility of successful surgery outcomes, and the acceptable difficulty of the procedure in MIS of sacroiliac luxation in toy breed dogs.MethodsMIS using 2.3-mm cannulated screws was demonstrated in 12 toy breed dog cadavers with sacroiliac luxation artificially induced. Pre and postoperative radiographs were used to evaluate the pelvic canal diameter ratio (PCDR), hemipelvic canal width ratio (HCWR), and reduction rate. Dorsoventral angle (DVA) and craniocaudal angle (CCA) of the inserted screw were obtained postoperative computed tomographic scan.ResultsThe statistically significant difference between the mean pre and postoperative PCDR was found (1.10 ± 0.12 and 1.26 ± 0.11, respectively; p = 0.002), and the mean HCWR close to 1.0 meaning symmetric pelvis also was obtained (0.97 ± 0.07). The mean DVA and CCA were 2.26° ± 1.33° and 2.60° ± 1.86°, respectively.ConclusionsMIS of sacroiliac luxation using 2.3-mm cannulated screws is applicable to toy breed dogs with acceptable difficulty.

An anatomical training model for cerebrospinal liquid collection and myelography in embalmed dog cadavers

An anatomical training model for cerebrospinal liquid collection and myelography in embalmed dog cadavers

Specific VOC-Profile of Decomposed Sasquatch Remains

A method using a thermal desorber combined with a gas chromatograph coupled to a mass spectrometer was proposed to identify the volatile organic compounds (VOCs) released in decomposed Sasquatch remains. It is known that specific VOCs are generated during the decomposition of Sasquatch and animal corpses that allow us to determine to which species the remains correspond, and the time elapsed since their dead. We found a combination of 8 compounds (ethyl propionate, propyl propionate, propyl butyrate, ethyl pentanoate, pyridine, diethyl disulfide, methyl (methylthio) ethyl disulfide and 3-methylthio1-propanol) that led to the distinction of Sasquatch remains from another animal remains. These markers would allow a more efficiently training of cadaver dogs or portable detection devices could be developed.

Iatrogenic Iliopsoas Tendon Injury May Occur during Femoral Head and Neck Ostectomy—An Ex-Vivo Study in Dogs

AbstractObjective The aim of this study was to determine if inadvertent iatrogenic damage to the iliopsoas tendon can occur during routine femoral head and neck ostectomy (FHO), using a cadaveric dog model.Study Design Four cadaveric specimens (eight hindlimbs total) of dogs that were humanely euthanatized for reasons unrelated to this study. Pre-experimental radiography confirmed absence of pelvic or femoral comorbidities. Each limb of each paired sample was randomly assigned as either dissection-only control or FHO. The simulated FHO procedures were performed by an American College of Veterinary Surgeons diplomate, and post-procedure radiography confirmed appropriate ostectomy. The FHO limbs underwent pre- and postoperative ultrasonographic investigation by an American College of Veterinary Radiology diplomate. Finally, the FHO limbs were grossly dissected, and abnormalities were documented.Results Gross visual damage was seen on all postoperative FHO limbs. The damage was most apparent in extreme external rotation of the limb at dissection. Yet, ultrasound investigation did not reveal changes associated with these gross lesions.Conclusion Iatrogenic inadvertent damage to the iliopsoas tendon may occur during routine FHO, as demonstrated in this ex vivo model; however, this result is not evidence for clinical relevance. A prospective clinical study is needed to assess if iliopsoas injury secondary to FHO has any clinical impact on recovery and limb function.

Use of a new device for gasless endosurgery in a laparoscopic diaphragmatic hernia repair ex vivo canine model: A pre-clinical study.

ObjectivesTo test the feasibility of a new device for gasless laparoscopy in providing working space for diaphragmatic hernia repair in an ex vivo canine model as a pre‐clinical study.Study designTechnical feasibility study.AnimalEight beagles and two greyhound cadavers (not client‐owned).MethodsThe new device was used for abdominal traction in gasless laparoscopic reconstruction of diaphragmatic hernias produced in dog cadavers. It consists of three main parts (vertical and horizontal rods, a three‐piece structure, and a 3D‐printed unit that incorporates slots for haemostatic forceps). Composite hernias (two incisions of about 4 cm) were closed by an intra‐corporeal suture [suture group (GS), n = 5] or by a central suture and a polypropylene mesh [mesh group (GM), n = 5]. Surgical steps were T1 (primary port access up to third port placement), T2 (defect development), and T3 (diaphragmatic reconstruction). Total surgical time (TT) was also recorded.ResultsThe defect was successfully developed and reconstructed in all cadavers. To close the defect, 7.0 ± 0.7 crossed mattress sutures were required in the GS, and 15.2 ± 1.9 hernia staples and one intra‐corporal suture were used in the GM. T3 was longer (p = 0.0076) in GS (50.00 ± 16.46 min) than in GM (23.24 ± 5.25 min). TT was 87.22 ± 19.23 min in GS and 66.45 ± 6.38 min in GM (p = 0.0547).ConclusionsGasless laparoscopic diaphragmatic hernia repair using the developed device is feasible in the canine cadaver model. Both suture and mesh graft techniques for experimental diaphragmatic herniorrhaphy can be performed using this new device in this pre‐clinical model.Clinical significanceThis new device for gasless laparoscopy allows diaphragmatic herniorrhaphy by intra‐corporeal suture or mesh implantation in ex vivo canine model. The device demonstrates potential for future use in clinical cases.

Mathematical Models for the Skin to Lumbosacral Epidural Distance in Dogs: A Cadaveric Computed-Tomography Study

Simple SummaryEpidural anaesthesia is readily performed in the lumbosacral area in dogs that are undergoing surgery of the hindlimbs or the abdomen. Common techniques that are used to identify the epidural space rely on subtle changes in tactile and audible sensations which are challenging for less experienced clinicians. Research in humans suggest that mathematical equations that are derived from body surface parameters may improve the success of epidural space identification. In a previous study by this research group, we developed two mathematical equations from computed tomography (CT) measurements using dog surface parameters and a body condition score to predict the skin to lumbosacral epidural space. In this study, we aimed to validate the equations in dog cadavers against a gold standard technique (epidurography). For one equation, the use of the occipital-coccygeal length and body condition score resulted in a high degree of correlation and agreement with the skin to lumbosacral epidural space of the cadavers. Future studies will determine whether the knowledge of the skin to lumbosacral epidural space distance prior to needle placement improves the success of epidural space identification.This study aimed to validate previously published computed tomography (CT) derived mathematical equations with the true skin to lumbosacral epidural distance (SLED) in dog cadavers. Phase 1: The lumbar region of 11 dog cadavers were scanned in sternal recumbency to determine the effect of cranial, neutral, and caudal pelvic limb positioning on the CT derived lumbosacral epidural distance (CLED). Phase 2: The epidural space was determined using contrast epidurography, and the SLED was analysed against the mathematical equations using a body condition score (BCS) and either the cadaveric occipital-coccygeal length (OCL) (Equation (1): = 7.3 + 0.05*OCL + 16.45*BCS) or the ilium wing distance (IWD) (Equation (2): = 3.5 + 0.56*IWD + 16.6*BCS). There were no differences detected between the pelvic limb positions and the CLED. Both equations demonstrated strong correlations (Equation (1): r = 0.7196; Equation (2): r = 0.7590) with the SLED. The level of agreement was greater for Equation (1) than with Equation (2) (concordance coefficient 0.6061 and 0.3752, respectively). Equation (1) also demonstrated a closer fit to the concordance line compared with Equation (2) (bias correction factor 0.8422 and 0.4960, respectively). Further studies in live anaesthetised dogs will help to determine the usefulness of the pre-procedural knowledge when performing lumbosacral epidurals.

Tibial Tuberosity Transposition Fixation with a Locking Plate during Medial Patellar Luxation Surgery: An Ex Vivo Mechanical Study.

The purpose of this study was to compare the load at failure, stiffness and mode of failure between three types of tibial tuberosity transposition fixation techniques: (a) pin and figure-8 tension band wire (Pin-TBW), (b) locking plate with pin and a tension band wire (Plate-Pin-TBW) and (c) locking plate with a pin (Plate-Pin). Six pairs of raccoon dog cadaveric tibiae were tested in Phase I Pin-TBW versus Plate-Pin-TBW and seven pairs in Phase II Plate-Pin-TBW versus Plate-Pin. One limb of each pair was randomly assigned to one of two groups for each phase. A tensile force was applied to the patellar ligament until construct failure. Pin-TBW (342N ± 54.7N) failed at a lower load than Plate-Pin-TBW (469N ± 77.3N), p = 0.00748, with all Pin-TBW failing by fracture and the majority of Plate-Pin-TBW failing by rupture of patellar ligament. Pin-TBW group Phase I, normalized with Plate-Pin-TBW Phase I, failed at a lower load than Plate-Pin group Phase II, normalized with Plate-Pin-TBW Phase II, p = 0.00467. There was no significant difference in mean load at failure, stiffness or mode at failure between the groups in the Phase II study. Although ex vivo mechanical testing does not replicate the postoperative live dog or cat, these results demonstrate lower construct strength of the Pin-TBW construct compared with the Plate-Pin construct in the raccoon dog cadaver model.

Prehospital Emergency Cricothyrotomy in Dogs Part 1: Experiences With Commercial Cricothyrotomy Kits

The surgical cricothyrotomy (CTT) has been recommended for emergency front of neck airway access (eFONA) during a cannot intubate, cannot oxygenate scenario for military working dogs (MWD) and civilian law enforcement working dogs (operational K9s). In prehospital and austere environments, combat medics and emergency medical service providers are expected to administer emergency medical care to working dogs and may only have emergency airway kits designed for humans at their disposal. The objective of this article is to provide a detailed description of the application of such devices in cadaver dogs and highlight potential alterations to manufacturer guidelines required for successful tube placement. The kits evaluated included the Portex® PCK, Melker universal cricothyrotomy kit and H&H® emergency cricothyrotomy kit. A novel technique for awake cricothyrotomy in the dog is also described, which can also be considered for in-hospital use, together with the open surgical method described for the H&H® kit. To the authors' knowledge, this is the first publication documenting and providing instruction on the application of commercial cricothyrotomy kits in dogs.

The feasibility and image quality of using soft embalming cadaver dogs and cats for radiographic and ultrasonographic training

The feasibility and image quality of using soft embalming cadaver dogs and cats for radiographic and ultrasonographic training

Patient‐specific 3D‐printed shelf implant for the treatment of hip dysplasia: Anatomical and biomechanical outcomes in a canine model

A solution for challenging hip dysplasia surgery could be a patient‐specific 3D‐printed shelf implant that is positioned extra‐articular and restores the dysplastic acetabular rim to normal anatomical dimensions. The anatomical correction and biomechanical stability of this concept were tested in a canine model that, like humans, also suffers from hip dysplasia. Using 3D reconstructed computed tomography images the 3D shelf implant was designed to restore the radiological dysplastic hip parameters to healthy parameters. It was tested ex vivo on three dog cadavers (six hips) with hip dysplasia. Each hip was subjected to a biomechanical subluxation test, first without and then with the 3D shelf implant in place. Subsequently, an implant failure test was performed to test the primary implant fixation. At baseline, the dysplastic hips had an average Norberg angle of 88 ± 3° and acetabular coverage of 47 ± 2% and subluxated at an average of 83 ± 2° of femoral adduction. After adding the patient‐specific shelf implants the dysplastic hips had an average Norberg angle of 122 ± 2° and acetabular coverage of 67 ± 3% and subluxated at an average of 117 ± 2° of femoral adduction. Implant failure after primary implant fixation occurred at an average of 1330 ± 320 Newton. This showed that the patient‐specific shelf implants significantly improved the coverage and stability of dysplastic hips in a canine model with naturally occurring hip dysplasia. The 3D shelf is a promising concept for treating residual hip dysplasia with a straightforward technology‐driven approach; however, the clinical safety needs to be further investigated in an experimental proof‐of‐concept animal study.

Influence of the Head Neck Position on Imaging Measurements Used to Assess the Craniovertebral Junction in Small Breed Dogs: A Cadaveric Study.

The study aimed to determine the influence of head neck position on imaging measurements used to assess the craniovertebral junction (CVJ) and to recommend the most appropriate position for the evaluation of the CVJ. A cross-sectional sample of adult dogs' cadavers was subjected to a computed tomography scan of the cranium and the cranial cervical region in three standardized head positions. Imaging measurements often used to assess the CVJ were measured. The influence of the head neck position, breed, weight and gender on imaging measurements was tested using repeated measures analysis of variance. Twenty-eight cadavers of small breed dogs were enrolled in the study. All cadavers examined had occipital dysplasia. All transarticular imaging measurements were dependent on the head neck position. In addition, the breed, weight and gender had an influence on several measurements. We recommend a standardized head neck position of 50 degrees flexion if quantitative imaging measurements of the CVJ are used to diagnose pathologies in this region. Future studies should focus on the definition of cut-off values for quantitative imaging measurements of the CVJ to differentiate between healthy and diseased small breed dogs. Regarding atlantoaxial instability, a combination of six parameters (C1-C2 angle, C1-C2 overlap, atlantoaxial distance, dens-to-axis length ratio, ventral compression index and clivus canal angle) is promising for its diagnosis.

Biomechanical Comparison of Three Stabilization Methods for Tibial Tuberosity Fractures in Dogs: A Cadaveric Study.

The aim of this study was to compare the biomechanical properties of a hybrid external skeletal fixator (HESF) construct to the placement of paired interfragmentary Kirschner wires alone, and pin and tension band wire (PTBW) fixation for the stabilization of simulated tibial tuberosity fractures in dogs. Tibias were harvested from 12 skeletally mature dog cadavers weighing 20 to 30 kg. An osteotomy was made through the base of the tibial tuberosity, which was subsequently repaired with either paired Kirschner wires, PTBW fixation or a HESF. A tensile load was applied to the tibial tuberosity until failure occurred. Mode of failure was described and biomechanical parameters obtained were compared between fixation groups. The PTBW fixation and HESF construct afforded greater stiffness and load at 3 mm of axial displacement compared with fixation with Kirschner wires alone. There was no significant difference in stiffness and load at 3 mm displacement between PTBW and HESF fixation. Failure occurred by bending and pullout of the Kirschner wires for all fixation groups, preceded by untwisting of the knot in PTBW specimens. The HESF may provide a favourable alternative to PTBW fixation for tibial tuberosity avulsion fracture stabilization in dogs with substantial remaining growth potential.

Feasibility and accuracy of 3D printed patient-specific skull contoured brain biopsy guides.

ObjectiveDesign 3D printed skull contoured brain biopsy guides (3D‐SCGs) from computed tomography (CT) or T1‐weighted magnetic resonance imaging (T1W MRI).Study DesignFeasibility study.Sample PopulationFive beagle dog cadavers and two client‐owned dogs with brain tumors.MethodsHelical CT and T1W MRI were performed on cadavers. Planned target point was the head of the caudate nucleus. Three‐dimensional‐SCGs were created from CT and MRI using commercially available open‐source software. Using 3D‐SCGs, biopsy needles were placed into the caudate nucleus in cadavers, and CT was performed to assess needle placement accuracy, followed by histopathology. Three‐dimensional‐SCGs were then created and used to perform in vivo brain tumor biopsies.ResultsNo statistical difference was found between the planned target point and needle placement. Median needle placement error for all planned target points was 2.7 mm (range: 0.86–4.5 mm). No difference in accuracy was detected between MRI and CT‐designed 3D‐SCGs. Median needle placement error for the CT was 2.8 mm (range: 0.86–4.5 mm), and 2.2 mm (range: 1.7–2.7 mm) for MRI. Biopsy needles were successfully placed into the target in the two dogs with brain tumors and biopsy was successfully acquired in one dog.ConclusionThree‐dimensional‐SCGs designed from CT or T1W MRI allowed needle placement within 4.5 mm of the intended target in all procedures, resulting in successful biopsy in one of two live dogs.Clinical SignificanceThis feasibility study justifies further evaluation of 3D‐SCGs as alternatives in facilities that do not have access to stereotactic brain biopsy.

Optimization and assessment of a novel gastric electrode anchoring system designed to be implanted by minimally invasive surgery

A novel electrode anchoring design and its implantation procedure, aiming for a minimally invasive solution for gastric electrical stimulation, are presented. The system comprises an anchor made of a flexible body embedding two needle-shaped electrodes. The electrodes can easily switch from a parallel position – to pierce the stomach – to a diverging position – enabling them to remain firmly anchored into the muscular layer of the stomach. Key device parameters governing anchoring stability were assessed on a traction test bench, and optimal values were derived. The device was then implanted in six dogs by open surgery to assess its anchoring durability in vivo. Computed tomography images showed that the electrodes remained well placed within the dogs’ gastric wall over the entire assessment period (more than one year). Finally, a prototype of a surgical tool for the minimally invasive device placement was manufactured, and the anchoring procedure was tested on a dog cadaver, providing the proof of concept of the minimally invasive implantation procedure. The use of our electrode anchoring system in long-term gastric electrical stimulation is promising in terms of implantation stability (the anchor withstands a force up to 0.81 N), durability (the anchor remains onto the stomach over one year) and minimal invasiveness of the procedure (the diameter of the percutaneous access is smaller than 12 mm). Moreover, the proposed design could have clinical applications in other hollow organs, such as the urinary bladder.

Measurement of the Femoral Anteversion Angle in Medium and Large Dog Breeds Using Computed Tomography.

To promote the development of an optimally functional total hip prosthesis for medium and large dog breeds, accurate measurements of the normal anatomy of the proximal femur and acetabular retroversion are essential. The aim of the current study was to obtain precise normal values of the femoral anteversion angle using computed tomography on cadavers of mature dogs with normal hip joints of both medium and large breeds. Based on the length of their femora 58 dogs were allocated either to group I: ≤195 mm or group II: >195 mm. In the study the femoral anteversion angle (FAA) was measured on each femur using multi-slice spiral computed tomography (CT). The data were processed as multi-planar and three-dimensional reconstructions using Advantage Workstation software. The CT measurements showed that the mean ± standard deviation (SD) FAA of group I was 31.34 ± 5.47° and in group II it was 31.02 ± 4.95°. There were no significant mean difference associations between the length of the femur and the femoral neck angle in either group (P > 0.05). The data suggest that a prosthesis FAA of 31 degrees would be suitable for a wide range of dog sizes.