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Abstract
OBJECTIVE
To investigate the effects of intervertebral distraction screw (IDS) fixation of the lumbosacral joint (LSJ) on the intervertebral foraminal area (IFA) and intervertebral stabilization of the LSJ and adjacent lumbar segments in dogs.
ANIMALS
7 healthy Beagles.
PROCEDURES
Dorsal laminectomy was performed at the LSJ in each dog to expose the intervertebral disk. The IDS was then inserted into the L7-S1 disk. Computed tomography was performed before and after laminectomy and after IDS insertion (intact, laminectomy, and IDS conditions, respectively) to measure the intervertebral range of motion (ROM) and intervertebral distance (ID) at L7-S1, L6-7, and L5-6 with the LSJ in a flexed and extended position. The intervertebral foramina stenosis rate was calculated from the intervertebral foramina area in entrance, middle, and exit zones. Results were compared among conditions.
RESULTS
The ROM at L7-S1 after IDS insertion was lower than that observed before and after laminectomy; no other differences were identified among conditions. With the LSJ in the flexed position, the ID at L7-S1 was larger after IDS insertion than before and after laminectomy; no other differences in ID were identified. In all evaluated zones, the stenosis rate was lower after IDS insertion than before and after laminectomy. No differences in ROM, ID, and stenosis rate were identified among conditions at L6-7 or L5-6.
CONCLUSIONS AND CLINICAL RELEVANCE
Results suggested that IDS fixation of the LSJ restricted lumbosacral ROM and prevented decreases in lumbosacral ID and IFA in healthy dogs. There were no changes at L6-7 and L5-6.
Abstract
OBJECTIVE
To compare a ventral and a left lateral endoscopic approach to coelioscopy in bearded dragons (Pogona vitticeps).
ANIMALS
18 adult bearded dragons.
PROCEDURES
In a randomized crossover design involving 2 surgical approaches, anesthetized bearded dragons first underwent coelioscopy with a ventral approach (left lateral of midline next to the umbilicus; animal positioned in dorsal recumbency) or left lateral approach (intercostal; animal positioned in right lateral recumbency) and then with the alternate approach. A 2.7-mm × 18-cm, 30° oblique telescope with a 4.8-mm operating sheath and CO2 insufflation at 2 to 5 mm Hg were used. Ease of entry into the coelom and ease of visual examination of visceral structures were scored.
RESULTS
Both approaches were straightforward, with the left lateral approach requiring significantly more time than the ventral approach. Scores for ease of visual examination for the heart, lungs, liver, stomach, intestines, pancreas, gallbladder, left kidney, gonads, and fat body were good to excellent. Visual examination of the spleen and adrenal glands was difficult in most animals via either approach. The left kidney, testis, and vas deferens were easier to see with the left lateral approach, whereas the pancreas in females and gallbladder in both sexes were easier to see with the ventral approach. All bearded dragons recovered without complications from the procedures, except for one with nephritis, renal gout, and hepatic necrosis.
CONCLUSIONS AND CLINICAL RELEVANCE
Both coelioscopy approaches could be safely and effectively used in bearded dragons. Choice of approach should be based on the coelomic structures requiring evaluation.
Abstract
OBJECTIVE
To compare heat generation and mechanical bone damage achieved with 2 tapered and 1 cylindrical transfixation pin taps in third metacarpal bones from equine cadavers.
SAMPLE
18 pairs (36 specimens) of third metacarpal bones from euthanized horses with no known metacarpal disease.
PROCEDURES
In each bone, an investigator drilled 3 holes for placement of a 6.3-mm cylindrical transfixation pin, a 6.3-mm tapered pin using a prototype tapered tap, and a 6.3-mm tapered pin using a revised tapered tap. One bone of each pair was tapped by hand and the other with an electric drill. Temperatures of the drill bits, reamers, and taps were measured and used to compare heat generation among tap groups and tapping methods (hand vs power tapping). Macrodamage (all bone pairs) and microdamage (6 bone pairs) were assessed.
RESULTS
The revised tapered tap resulted in less heat generation and less total thread microdamage, compared with the prototype tapered and cylindrical taps. Power tapping created less bone damage but higher temperatures than did hand tapping for all bone groups.
CONCLUSIONS AND CLINICAL RELEVANCE
The revised tap design for tapered pin insertion was superior to the prototype tap design and yielded similar or less bone damage than achieved with cylindrical pin insertion in equine third metacarpal bone specimens. We recommend careful hand tapping for tapered pin insertion rather than power tapping, which generated greater heat. The revised tapered tap could be expected to perform better than a cylindrical pin tap in terms of thermal and mechanical microdamage and should be used for insertion of tapered transfixation pins.
Abstract
OBJECTIVE
To assess the effects of 3 intra-abdominal pressures (IAPs) on pneumoperitoneal (laparoscopic working space) volume in domestic rabbits (Oryctolagus cuniculus).
ANIMALS
6 female New Zealand White rabbits.
PROCEDURES
A Latin-square design was used to randomly allocate sequences of 3 IAPs (4, 8, and 12 mm Hg) to each rabbit in a crossover study. Rabbits were anesthetized, subumbilical cannulae were placed, and CT scans were performed to obtain baseline measurements. Each IAP was achieved with CO2 insufflation and maintained for ≥ 15 minutes; CT scans were performed with rabbits in dorsal, left lateral oblique, and right lateral oblique recumbency. The abdomen was desufflated for 5 minutes between treatments (the 3 IAPs). Pneumoperitoneal volumes were calculated from CT measurements with 3-D medical imaging software. Mixed linear regression models evaluated effects of IAP, rabbit position, and treatment order on working space volume.
RESULTS
Mean working space volume at an IAP of 8 mm Hg was significantly greater (a 19% increase) than that at 4 mm Hg, and was significantly greater (a 6.9% increase) at 12 mm Hg than that at 8 mm Hg. Treatment order, but not rabbit position, also had a significant effect on working space. Minor adverse effects reported in other species were observed in some rabbits.
CONCLUSIONS AND CLINICAL RELEVANCE
A nonlinear increase in abdominal working space was observed with increasing IAP. Depending on the type of procedure and visual access requirements, IAPs > 8 mm Hg may not provide a clinically important benefit for laparoscopy in rabbits.
Abstract
OBJECTIVE
To investigate in vitro effects of triclosan coating of suture materials on the growth of clinically relevant bacteria isolated from wounds in dogs.
SAMPLE
6 types of suture material and 10 isolates each of methicillin-susceptible Staphylococcus pseudintermedius, methicillin-resistant S pseudintermedius, Escherichia coli, and AmpC β-lactamase and extended-spectrum β-lactamase–producing E coli from clinical wound infections.
PROCEDURES
Isolates were cultured on Mueller-Hinton agar with 3 types of triclosan-coated suture, uncoated counterparts of the same suture types, and positive and negative controls. Zones of inhibition (ZOIs) were measured after overnight incubation. Sustained antimicrobial activity assays were performed with susceptible isolates. The ZOI measurements and durations of sustained antimicrobial activity were compared among suture types and isolates by statistical methods. Suture surface characteristics and bacterial adherence were evaluated qualitatively with scanning electron microscopy.
RESULTS
ZOIs were generated only by triclosan-coated materials; triclosan-coated suture had sustained antimicrobial activity (inhibition) for 3 to 29 days against all tested pathogens. The ZOIs around triclosan-coated suture were significantly greater for S pseudintermedius isolates than for E coli isolates. Bacterial adherence to uncoated polyglactin-910 was greatest, followed by triclosan-coated polyglactin-910, and then uncoated monofilament sutures, with least adherence to coated monofilament sutures.
CONCLUSIONS AND CLINICAL RELEVANCE
Surface characteristics of suture materials may be as important or more important than triclosan coating for microbial inhibition; however, triclosan coating appeared to affect bacterial adherence for multifilament sutures. Triclosan-coated, particularly monofilament, sutures inhibited pathogens commonly isolated from wounds of dogs, including multidrug-resistant bacteria. Further studies are required to assess clinical efficacy of triclosan-coated suture materials in vivo.
Abstract
OBJECTIVE
To compare laryngeal impedance, in terms of air flow and pressure, following arytenoid corniculectomy (COR) versus 3 other airway interventions (left-sided laryngoplasty with ipsilateral ventriculocordectomy [LLP], LLP combined with COR [LLPCOR], and partial arytenoidectomy [PA]) performed on cadaveric equine larynges with simulated left recurrent laryngeal neuropathy (RLN) and to determine whether relative laryngeal collapse correlated with the interventions performed.
SAMPLE
28 cadaveric equine larynges.
PROCEDURES
Each larynx in states of simulated left RLN alone and with airway interventions in the order LLP, LLPCOR, COR, and PA was evaluated in a box model construct that replicated upper airway flow mechanics consistent with peak exercise in horses. Results for impedance, calculated from airflow and pressure changes, were compared between states for each larynx. Multivariable mixed-effects analysis controlling for repeated measures within larynx was performed to calculate the predicted mean impedance for each state.
RESULTS
Results indicated that tracheal adapter diameter, individual larynx properties, airway intervention, and relative laryngeal collapse affected laryngeal impedance. The LLP and LLPCOR interventions had the lowest impedance, whereas the COR and PA interventions did not differ substantially from the simulated left RLN state. Residual intraclass correlation of the model was 27.6 %.
CONCLUSIONS AND CLINICAL RELEVANCE
Although impedance was higher for the simulated left RLN with the COR intervention state than with the LLP intervention state, given the clinical success of PA for treating RLN in horses and the similar results for the COR and PA intervention states in the present study, the use of COR warrants further investigation. The residual interclass correlation suggested that individual laryngeal variation affected impedance and may have a clinical effect.
Abstract
OBJECTIVE
To determine the optimal intercostal space (ICS) for thoracoscopic-assisted pulmonary surgery for lung lobectomy in cats.
SAMPLE
8 cat cadavers.
PROCEDURES
Cadavers were placed in lateral recumbency. A 5-cm minithoracotomy incision was made in the middle third of ICS 4 through 7 on the left side and 4 through 8 on the right side, and a wound retractor device was placed. A camera port was made in the middle third of ICS 9. Each lung lobe was sequentially exteriorized at each respective ICS. A thoracoabdominal stapler was placed to simulate a lung lobectomy, and distance from the stapler anvil to the hilus was measured.
RESULTS
For the left cranial lung lobe, there was no significant difference in median distance from the stapler anvil to the pulmonary hilus for ICS 4 through 6. Simulated lobectomy of the left caudal lung lobe performed at ICS 5 and 6 resulted in a significantly shorter distance, compared with lobectomy performed at ICS 4 and 7. Simulated lobectomy of the right cranial and right middle lung lobes performed at ICS 4 and 5 resulted in a significantly shorter distance, compared with lobectomy performed at ICS 7. Simulated lobectomy of the accessory and right caudal lung lobes at ICS 5 and 6 resulted in a significantly shorter distance than for lobectomy performed at ICS 8.
CONCLUSIONS AND CLINICAL RELEVANCE
An optimal ICS for a minithoracotomy incision was determined for thoracoscopic-assisted lung lobectomy in cats.
Abstract
OBJECTIVE
To determine effects of bite depth for placement of an epitendinous suture on the biomechanical strength and gap formation of repaired canine tendons.
SAMPLE
48 superficial digital flexor tendons (SDFTs) obtained from 24 canine cadavers.
PROCEDURES
Tendons were assigned to 3 groups (16 tendons/group). Each SDFT was transected and then repaired with a continuous epitendinous suture placed with a bite depth of 1, 2, or 3 mm for groups 1, 2, and 3, respectively. Specimens were loaded to failure. Failure mode, gap formation, yield force, peak force, and failure force were analyzed.
RESULTS
Yield, peak, and failure forces differed significantly between groups 1 and 3 and groups 2 and 3 but not between groups 1 and 2. Comparison of the force resisted at 1 and 3 mm of gapping revealed a significant difference between groups 1 and 3 and groups 2 and 3 but not between groups 1 and 2. Failure mode did not differ among groups; suture pull-through occurred in 43 of 48 (89.6%) specimens.
CONCLUSIONS AND CLINICAL RELEVANCE
Increasing bite depth of an epitendinous suture toward the center of the tendon substance increased repair site strength and decreased the incidence of gap formation. Repair of tendon injuries in dogs by use of an epitendinous suture with bites made deep into the tendon should result in a stronger repair, which potentially would allow loading and rehabilitation to begin sooner after surgery. Suture techniques should be investigated in vivo to determine effects on tendinous healing and blood supply before clinical implementation.
Abstract
OBJECTIVE
To evaluate effects of bite distance of an interlocking horizontal mattress epitendinous suture (IHMES) from the repair site on tensile strength of canine tendon repairs.
SAMPLE
72 canine cadaveric superficial digital flexor tendons (SDFTs).
PROCEDURES
Transverse tenotomy was performed, and SDFTs were repaired with a locking-loop construct (LL construct) or 3 LL constructs with IHMES suture bites placed 5 (LL + 5ES construct), 10 (LL + 10ES construct), or 15 (LL + 15ES construct) mm from the transection site (18 SDFTs/group). Constructs were loaded to failure. Load at 1− and 3-mm gapping, yield force, failure load, and failure mode were evaluated.
RESULTS
Mean ± SD yield force and failure load for LL constructs were significantly lower than for IHMES constructs. Load at 1− and 3-mm gapping was significantly higher for IHMES constructs. Increasing the bite distance significantly increased construct strength (134.4 ± 26.1 N, 151.0 ± 16.8 N, and 182.1 ± 23.6 N for LL + 5ES, LL + 10ES, and LL + 15ES constructs, respectively), compared with strength for the LL construct. Failure mode differed significantly among constructs when an IHMES was used.
CONCLUSIONS AND CLINICAL RELEVANCE
Addition of an IHMES to an LL construct led to increased ultimate tensile strength by 2.5 times and significantly reduced gap formation. Increasing the IHMES bite distance increased yield force by 2.1, 2.3, and 2.7 times for bites placed 5, 10, and 15 mm from the tenotomy, respectively. Positioning an IHMES at a greater distance from the repair site provided superior biomechanical strength for tendon repairs in dogs.
Abstract
OBJECTIVE
To evaluate accuracy of articular surfaces determined by use of 2 perpendicular CT orientations, micro-CT, and laser scanning.
SAMPLE
23 cat cadavers.
PROCEDURES
Images of antebrachia were obtained by use of CT (voxel size, 0.6 mm) in longitudinal orientation (CTLO images) and transverse orientation (CTTO images) and by use of micro-CT (voxel size, 0.024 mm) in a longitudinal orientation. Images were reconstructed. Craniocaudal and mediolateral length, radius of curvature, and deviation of the articular surface of the distal portion of the radius of 3-D renderings for CTLO, CTTO, and micro-CT images were compared with results of 3-D renderings acquired with a laser scanner (resolution, 0.025 mm).
RESULTS
Measurement of CTLO and CTTO images overestimated craniocaudal and mediolateral length of the articular surface by 4% to 10%. Measurement of micro-CT images underestimated craniocaudal and mediolateral length by 1%. Measurement of CTLO and CTTO images underestimated mediolateral radius of curvature by 15% and overestimated craniocaudal radius of curvature by > 100%; use of micro-CT images underestimated them by 3% and 5%, respectively. Mean ± SD surface deviation was 0.26 ± 0.09 mm for CTLO images, 0.30 ± 0.28 mm for CTTO images, and 0.04 ± 0.02 mm for micro-CT images.
CONCLUSIONS AND CLINICAL RELEVANCE
Articular surface models derived from CT images had dimensional errors that approximately matched the voxel size. Thus, CT cannot be used to plan conforming arthroplasties in small joints and could lack precision when used to plan the correction of a limb deformity or repair of a fracture.
