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Abstract
OBJECTIVE
To compare intraoperative and short-term postoperative variables pertaining to laparoscopic ovariectomy (LapOVE) and open ovariectomy (OVE) in rabbits (Oryctolagus cuniculus).
ANIMALS
Twelve 4− to 5-month-old female New Zealand White rabbits.
PROCEDURES
Rabbits were randomly assigned to undergo LapOVE (n = 6) or OVE (6), with a vessel-sealing device used to seal and transect the ovarian pedicles. Laparoscopic ovariectomy was performed with a 3-port approach. Variables were measured during surgery (surgery and anesthesia times and incision lengths) and for up to 7 days after surgery (food consumption, feces production, body weight, vital parameters, blood glucose and cortisol concentrations, abdominal palpation findings, facial grimace scale scores, and ethograms).
RESULTS
Mean surgery (43.2 vs 21.7 minutes) and anesthesia (76.2 vs 48.8 minutes) times were longer and mean incision length was shorter (24.0 vs 41.5 mm) for LapOVE versus OVE. No significant differences in postoperative variables were identified between groups. During LapOVE, small intestinal perforation occurred in 1 rabbit, which was then euthanized. Postoperative complications for the remaining rabbits included superficial incisional dehiscence (LapOVE, 1/5; OVE, 2/6), subcutaneous emphysema (LapOVE, 1/5; OVE, 0/6), and seroma formation (LapOVE, 1/5; OVE, 0/6).
CONCLUSIONS AND CLINICAL RELEVANCE
Surgery time for LapOVE was twice that of OVE, and LapOVE resulted in unique complications in rabbits. No evidence of a reduction in pain or faster return to baseline physiologic status was found for LapOVE. Further evaluation of LapOVE in rabbits is warranted, with modification to techniques used in this study or a larger sample size.
Abstract
OBJECTIVE
To determine whether jejunal serosal patches could securely seal large, open defects in duodenal segments harvested from canine cadavers and to compare intraluminal pressures at which leakage first occurred and maximal intraluminal pressures for repaired duodenal segments between 2 suture patterns.
SAMPLE
Duodenal and jejunal segments from 9 canine cadavers.
PROCEDURES
20 constructs were created through repair of large, open duodenal defects with circumferential suturing of an intact jejunal segment (jejunal serosal patch). Constructs were randomly assigned to have the serosal patch anastomosed to the duodenal segment by a simple continuous or simple interrupted suture pattern. The pressure at which the first leakage was observed and the maximum pressure obtained during testing were recorded and compared between suture patterns.
RESULTS
Initial leakage pressure was significantly higher with the simple interrupted pattern (mean ± SD, 68.89 ± 5.62 mm Hg), compared with the simple continuous pattern (59.8 ± 20.03 mm Hg). Maximum intraluminal pressures did not significantly differ between the simple interrupted (91 ± 8.27 mm Hg) and simple continuous patterns (90.7 ± 16.91 mm Hg). All constructs, regardless of suture pattern, withstood supraphysiologic pressures.
CONCLUSIONS AND CLINICAL RELEVANCE
Jejunal serosal patches adequately sealed large, open duodenal defects and prevented leakage in these constructs. Constructs with simple continuous or simple interrupted suture patterns withstood physiologic and supraphysiologic intraluminal pressures, although constructs with a simple interrupted suture pattern initially leaked at higher pressures. (Am J Vet Res 2020;81:985–991)
Abstract
OBJECTIVE
To determine the degree of histomorphometric damage in dorsal colon and pelvic flexure biopsy specimens (DCBSs and PFBSs, respectively) obtained from horses with large colon volvulus (LCV) and assess the accuracy of predicting short-term outcome for those horses on the basis of DCBS or PFBS characteristics.
ANIMALS
18 horses with ≥ 360° LCV that underwent large colon resection.
PROCEDURES
During surgery, biopsy specimens from the dorsal colon resection site and the pelvic flexure (when available) were collected from each horse. Interstitial-to-crypt (I:C) ratio (ratio of the lamina propria space occupied by the interstitium to that occupied by crypts), hemorrhage within the lamina propria (mucosal hemorrhage score [MHS] from 0 to 4), and percentage losses of glandular and luminal epithelium were determined in paired biopsy specimens and compared to determine optimal cutoff values for calculating the accuracy of DCBS and PFBS characteristics to predict short-term outcome (survival or nonsurvival after recovery from surgery).
RESULTS
Paired biopsy specimens were obtained from 17 of the 18 horses. The I:C ratio and percentage glandular epithelial loss differed between DCBSs and PFBSs. For DCBSs, an I:C ratio ≥ 0.9 and MHS ≥ 3 each predicted patient nonsurvival with 77.8% accuracy. For PFBSs, an I:C ratio ≥ I and MHS ≥ 3 predicted patient nonsurvival with 70.6% and 82.4% accuracy, respectively.
CONCLUSIONS AND CLINICAL RELEVANCE
Although different, histomorphometric measurements for either DCBSs or PFBSs could be used to accurately predict short-term outcome for horses with LCV that underwent large colon resection, and arguably PFBSs are easier to collect.
Abstract
OBJECTIVE
To compare initial leak pressure (ILP) between cadaveric canine and synthetic small intestinal segments that did and did not undergo enterotomy.
SAMPLE
Eight 8-cm grossly normal jejunal segments from 1 canine cadaver and eight 8-cm synthetic small intestinal segments.
PROCEDURES
Intestinal segments were randomly assigned to undergo enterotomy (6 cadaveric and 6 synthetic segments) or serve as untreated controls (2 cadaveric and 2 synthetic segments). For segments designated for enterotomy, a 2-cm full-thickness incision was created along the antimesenteric border. The incision was closed in a single layer with 4-0 suture in a simple continuous pattern. Leak testing was performed with intestinal segments occluded at both ends and infused with dilute dye solution (999 mL/h) until the solution was observed leaking from the suture line or serosal tearing occurred. Intraluminal pressure was continuously monitored. The ILP at construct failure was compared between cadaveric and synthetic control segments and between cadaveric and synthetic enterotomy segments.
RESULTS
Mean ± SD ILP did not differ significantly between cadaveric (345.11 ± 2.15 mm Hg) and synthetic (329.04 ± 24.69 mm Hg) control segments but was significantly greater for cadaveric enterotomy segments (60.77 ± 15.81 mm Hg), compared with synthetic enterotomy segments (15.03 ± 6.41 mm Hg).
CONCLUSIONS AND CLINICAL RELEVANCE
Leak testing should not be used to assess the accuracy or security of enterotomy suture lines in synthetic intestinal tissue. Synthetic intestinal tissue is best used for students to gain confidence and proficiency in performing enterotomies before performing the procedure on live animals.
Abstract
OBJECTIVE
To evaluate holding security of 4 friction knots created with various monofilament and multifilament sutures in a vascular ligation model.
SAMPLE
280 friction knot constructs.
PROCEDURES
10 friction knots of 4 types (surgeon's throw, Miller knot, Ashley modification of the Miller knot, and strangle knot) created with 2-0 monofilament (polyglyconate, polydioxanone, poliglecaprone-25, and glycomer-631) and braided multifilament (silk, lactomer, and polyglactin-910) sutures were separately tied on a mock pedicle and pressure tested to the point of leakage. Linear regression analysis was performed to compare leakage pressures among suture materials (within friction knot type) and among knot types (within suture material).
RESULTS
Mean leakage pressure of surgeon's throws was significantly lower than that of all other knots tested, regardless of the suture material used. All the other knots had mean leakage pressures considered supraphysiological. Significant differences in mean leakage pressure were detected between various friction knots tied with the same type of suture and various suture types used to create a given knot. Variability in leakage pressure among knots other than the surgeon's throw was greatest for poliglecaprone-25 and lowest for polydioxanone.
CONCLUSIONS AND CLINICAL RELEVANCE
Most differences in knot security, although statistically significant, may not have been clinically relevant. However, results of these in vitro tests suggested the surgeon's throw should be avoided as a first throw for pedicle ligation and that poliglecaprone-25 may be more prone to friction knot slippage than the other suture materials evaluated.
Abstract
OBJECTIVE
To compare the bursting strength of the uterine horns (UHs) and cervical-vestibule junction (CVJs) of rabbits following sealing with a vessel-sealing device (VSD) or encircling ligatures.
SAMPLE
UHs and CVJs collected from 30 rabbit (Oryctolagus cuniculus) cadavers.
PROCEDURES
UHs and CVJs were randomly assigned to sealing with encircling Miller knot ligatures (LIG; n = 10 CVJs and 20 UHs) or a VSD (12 CVJs and 24 UHs). Lumens were infused with saline (0.9% NaCl) solution under pressure until seals burst or to a maximum pressure of 300 mm Hg.
RESULTS
For CVJs, median (range) bursting pressure of the LIG and VSD groups was > 300 mm Hg (224 to > 300 mm Hg) and 35 mm Hg (0 to 60 mm Hg), respectively. Five of 12 CVJs in the VSD group failed at pressures < 33 mm Hg. For UHs, median (range) bursting pressure of the LIG and VSD groups was 255 mm Hg (120 to > 300 mm Hg) and 154 mm Hg (range, 44 to 202 mm Hg), respectively.
CONCLUSIONS AND CLINICAL RELEVANCE
The evaluated VSD was effective in sealing UHs at bursting pressures well in excess of expected physiologic pressures, indicating that the VSD may be useful for ovariectomy procedures in rabbits. However, CVJ seals created with the VSD were ineffective and could potentially burst at low pressures, which could predispose to urine entering the abdomen. Given these results, we do not recommend sealing of the CVJ with a VSD for ovariohysterectomy in rabbits.
Abstract
OBJECTIVE
To determine the optimal energy profile for and to assess the feasibility and efficacy of ultrasonographic and laparoscopic guidance for microwave ablation (MWA) of clinically normal canine ovaries.
SAMPLE
44 extirpated ovaries from 22 healthy dogs.
PROCEDURES
In the first of 2 trials, 13 dogs underwent oophorectomy by routine laparotomy. Extirpated ovaries underwent MWA at 45 W for 60 (n = 11) or 90 (12) seconds; 3 ovaries did not undergo MWA and served as histologic controls. Ovaries were histologically evaluated for cell viability. Ovaries without viable cells were categorized as completely ablated. Histologic results were used to identify the optimal MWA protocol for use in the subsequent trial. In the second trial, the ovaries of 9 dogs underwent MWA at 45 W for 90 seconds in situ. Ultrasonographic guidance for MWA was deemed unfeasible after evaluation of 1 ovary. The remaining 17 ovaries underwent MWA with laparoscopic guidance, after which routine laparoscopic oophorectomy was performed. Completeness of ablation was histologically assessed for all ovaries.
RESULTS
2 ovaries were excluded from the trial 1 analysis because of equivocal cell viability. Six of 11 ovaries and 10 of 10 ovaries that underwent MWA for 60 and 90 seconds, respectively, were completely ablated. In trial 2, laparoscopic-guided MWA resulted in complete ablation for 12 of 17 ovaries. Dissection of the ovarian bursa for MWA probe placement facilitated complete ablation.
CONCLUSIONS AND CLINICAL RELEVANCE
Laparoscopic-guided MWA at 45 W for 90 seconds was feasible, safe, and effective for complete ablation of clinically normal ovaries in dogs.
Abstract
OBJECTIVE
To compare the biomechanical strength and incidence of gap formation among canine superficial digital flexor tendon (SDFT) constructs that underwent core tenorrhaphy only and those in which the core tenorrhaphy was augmented with skin staples or a continuous Silfverskiold cross-stitch (SXS) suture pattern.
SAMPLE
42 cadaveric forelimb SDFTs from 21 musculoskeletally normal dogs.
PROCEDURES
Tendons were randomly assigned to 3 groups (14 SDTFs/group), sharply transected, and repaired with a core locking-loop suture alone (group 1) or augmented with circumferential placement of skin staples (group 2) or a continuous SXS suture pattern (group 3) in the epitenon. All constructs underwent a single load-to-failure test. Yield, peak, and failure loads, incidence of gap formation, and mode of failure were compared among the 3 groups.
RESULTS
Mean yield, peak, and failure loads differed significantly among experimental groups and were greatest for group 3 and lowest for group 1 constructs. The incidence of gap formation differed among the tested groups and was lowest for group 3 and highest for group 1. The most common mode of construct failure was the suture pulling through the tendon for group 1, staple deformation for group 2, and epitendinous suture breakage for group 3.
CONCLUSIONS AND CLINICAL RELEVANCE
Results indicated epitendinous placement of skin staples around a core SDFT tenorrhaphy site improved the biomechanical strength and resistance to gap formation for the repair but was inferior to epitendinous placement of SXS sutures. Further research is necessary before skin staples are used for tenorrhaphy augmentation in clinical patients.
Abstract
OBJECTIVE
To compare load-to-failure results for laparoscopic absorbable fixation straps (AFSs) deployed at various angles and for AFSs versus absorbable knotless (barbed) suture when used in simulated total laparoscopic gastropexy (TLG) in specimens from cadaveric dogs.
SAMPLE
30 stomach and abdominal body wall specimens.
PROCEDURES
Specimens were assigned to 1 of 3 groups for use in simulated TLG constructs for comparisons of load-to-failure results for single AFSs deployed at 30°, 60°, or 90° (AFS-angle group; n = 10) or for a gastropexy span of 4 to 5 cm achieved with 3-0 absorbable knotless (barbed) monofilament suture applied in a simple continuous pattern (TLG-1; 10) versus 8 AFSs applied with a deployment angle > 30° (TLG-2; 10). A 1-way ANOVA was used to compare results among AFS deployment angles (30°, 60°, or 90°) and between TLG-1 and TLG-2.
RESULTS
Mean ± SD load to failure for the AFS-angle group was significantly higher for the AFS deployment angles of 60° (8.00 ± 3.90 N) and 90° (12.71 ± 8.00 N), compared with 30° (5.17 ± 1.90 N). However, no substantial difference was detected in the mean ± SD load to failure for TLG-1 (39.18 ± 7.1 N) versus TLG-2 (31.43 ± 10.86 N).
CONCLUSIONS AND CLINICAL RELEVANCE
Results of the present study supported the potential use of AFSs in gastropexy in dogs; however, prospective clinical research with adequate long-term follow-up is warranted before recommendations can be made.
Abstract
OBJECTIVE
To evaluate the time and number of laser beam passes required to make full-thickness skin incisions and extent of laser-induced tissue artifacts following use of a CO2 laser at various settings.
SAMPLE
24 skin specimens from six 5-month-old porcine carcasses.
PROCEDURES
4 full-thickness skin specimens were harvested from the flank regions of each carcass within 30 minutes after euthanasia and randomly assigned to 4 treatment groups. Three 5-cm-long incisions were made in each specimen with a CO2 laser (beam diameter, 0.4 mm) set to deliver a continuous wave of energy alone (groups 1 and 2) or in superpulse mode (groups 3 and 4) at 10 (groups 1 and 3) or 20 (groups 2 and 4) W of power. The time and number of passes required to achieve a full-thickness incision were recorded, and extent of laser-induced tissue artifact (as determined by histologic evaluation) was compared among the 4 groups.
RESULTS
Mean time required to make a full-thickness skin incision for groups 2 and 4 (power, 20 W) was significantly less than that for groups 1 and 3 (power, 10 W). Mean number of passes was lowest for group 2 (continuous wave at 20 W). Extent of laser-induced tissue artifact was greatest for group 4 (superpulse mode at 20 W).
CONCLUSIONS AND CLINICAL RELEVANCE
Results provided preliminary information regarding use of CO2 lasers to make skin incisions in veterinary patients. In vivo studies are necessary to evaluate the effect of various CO2 laser settings on tissue healing and patient outcome.
