Evaluation of the internal vertebral venous plexus, vertebral canal, dural sac, and vertebral body via nonselective computed tomographic venography in the cervical vertebral column in healthy dogs.

OBJECTIVE: To evaluate nonselective computed tomographic (CT) venography for evaluating the cervical internal vertebral venous plexus (IVVP), define the diameter and area dimensions of the IVVP, and determine the relationship between dimensions of the cervical IVVP and other vertebral components in medium-sized dogs. Animals-6 healthy dogs that weighed 18 to 27 kg. Procedure-Helical CT scans were performed from C1 to C7 before and after IV injection of contrast medium (480 mg of iodine/kg) and a continuous infusion (240 mg of iodine/kg). Image data were transferred to a CT workstation, and measurements were performed on displayed transverse images. Diameter and area measurements of the vertebral canal, dural sac, IVVP, and vertebral body were obtained at C3 to C7. RESULTS: Opacification of vertebral venous structures was achieved in all dogs with no adverse reactions. Sagittal diameters of the IVVP for C3 to C7 ranged from 0.6 to 3.2 mm. Transverse diameters ranged from 2.32 to 5.74 mm. The IVVP area represented 12.4% of the mean vertebral canal transverse area and 30.61% of the mean vertebral epidural space area. Area measurements of the IVVP were significantly correlated with vertebral canal area and dural sac area. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that nonselective CT venography is a safe, sensitive method for performing morphometric assessments of the cervical IVVP in dogs. Findings support the theory that there may be a physiologic or developmental relationship between cervical vertebral canal components.

Comparison of postoperative pain after ovariohysterectomy by harmonic scalpel-assisted laparoscopy compared with median celiotomy and ligation in dogs.

OBJECTIVE: To compare the effects of postoperative pain after ovariohysterectomy by harmonic scalpel-assisted laparoscopy (HALO) and traditional ovariohysterectomy (OVH) in dogs. STUDY DESIGN: A randomized, blinded, prospective study. SAMPLE POPULATION: Sixteen, purpose-bred, intact female, Beagle dogs. METHODS: Dogs were divided into 2 groups: Group 1 (8 dogs), which had OVH by HALO, and Group 2 (8 dogs), which had traditional OVH. Physiologic data, abdominal nociceptive threshold scores, and University of Melbourne pain scores (UMPS) were recorded at 2, 6, 12, 24, 48, and 72 hours after surgery. Blood samples for measurement of plasma cortisol, glucose, and creatine phosphokinase (CPK) concentrations were collected at the time of the incision, and 2, 6, 12, 24, 48, and 72 hours after surgery. RESULTS: No significant surgical complications occurred. The HALO mean surgical time was significantly longer (55.7 minutes) than traditional OVH (31.7 minutes). No significant differences were observed between groups for the pain measures of heart rate, respiratory rate, temperature, CPK, and glucose concentrations. The OVH group had significantly higher mean plasma cortisol levels at hour 2 after surgery than the HALO group (P=.0001). The mean UMPS were significantly higher in OVH than the HALO group at all postoperative times (P=.0001). The mean nociceptive threshold measurements revealed significantly higher tolerated palpation pressures in HALO than OVH at all postoperative times, except hour 72 (P=.0002). CONCLUSIONS: Dogs appeared to be in less pain with HALO than OVH. The harmonic scalpel coagulated ovarian and uterine vessels completely with minimal collateral damage to surrounding tissues. CLINICAL RELEVANCE: HALO is a safe alternative to OVH and offers a minimally invasive and less painful method of surgery.

Hemodynamic effects of orally administered carvedilol in healthy conscious dogs.

OBJECTIVE: To evaluate the hemodynamic effects of orally administered carvedilol in healthy dogs with doses that might be used to initiate treatment in dogs with congestive heart failure. ANIMALS: 24 healthy dogs. PROCEDURE: Dogs were randomly allocated to receive carvedilol PO at a dose of 1.56, 3.125, or 12.5 mg, twice daily for 7 to 10 days; 6 dogs served as controls. Investigators were blinded to group assignment. Hemodynamic variables were recorded prior to administration of the drug on day 1 and then 2, 4, and 6 hours after the morning dose on day 1 and days 7 to 10. Change in heart rate after IV administration of 1microg of isoproterenol/kg and change in systemic arterial blood pressure after IV administration of 8 microg of phenylephrine/kg were recorded 2 and 6 hours after administration of carvedilol. RESULTS: Administration of carvedilol did not significantly affect resting hemodynamic variables or response to phenylephrine. The interaction of day and carvedilol dose had a significant effect on resting heart rate, but a significant main effect of carvedilol dose on resting heart rate was not detected. Increasing carvedilol dose resulted in a significant linear decrease in heart rate response to isoproterenol. CONCLUSIONS AND CLINICAL RELEVANCE: In healthy conscious dogs, orally administered carvedilol at mean doses from 0.08 to 0.54 mg/kg given twice daily did not affect resting hemodynamics. Over the dose range evaluated, there was a dose-dependent attenuation of the response to isoproterenol, which provided evidence of beta-adrenergic receptor antagonism.

Evaluation of analgesia provided by the administration of epidural ketamine in dogs with a chemically induced synovitis.

OBJECTIVE: To determine if epidural ketamine provides analgesia in dogs with a chemically induced synovitis. STUDY DESIGN: Prospective randomized experimental trial. ANIMALS: Thirty-two healthy, adult mongrel dogs (13-30 kg). METHODS: (Part I) Synovitis was induced in the right stifle of 16 dogs and allowed to develop for 12 hours. Epidural injection at the lumbosacral space of either ketamine (2 mg kg(-1); n = 8) or placebo (n = 8) was performed. Limb use and pain were measured using a force platform and numerical rating scale (NRS). Assessments were performed before and at 12, 14, 16, 18, 20, and 24 hours after the induction of synovitis. (Part II) Epidural injection of either ketamine (n = 8) or placebo (n = 8) was performed immediately before the induction of synovitis. Analgesia was assessed as in Part I. Assessments occurred before and at 2, 4, 6, 8, and 12 hours after the induction of synovitis. RESULTS: (Part I) Vertical ground reaction forces (VGRF) significantly decreased and NRS scores of total pain significantly increased after the induction of synovitis in all dogs (p < 0.05). No significant differences in VGRF or NRS scores were measured between treatment groups at any assessment period. (Part II) Dogs that received ketamine had significantly lower NRS scores 2 hours after treatment (p < 0.05). NRS scores did not differ between groups at any other evaluation. VGRF did not differ significantly between treatment groups at any assessment period. CONCLUSION: Epidural ketamine at a dose of 2 mg kg(-1) administered after the development of synovitis does not provide significant levels of analgesia. Administration of ketamine before the induction of synovitis significantly decreased the NRS score 2 hours post-induction. CLINICAL RELEVANCE: Administration of epidural ketamine before tissue injury may provide analgesia of short duration in dogs.

Laparoscopic ovariohysterectomy in nine dogs.

Minimally invasive surgery has been found in humans to reduce pain, incidence of infections, and duration of hospitalization. Minimally invasive procedures are also being described in veterinary medicine. Laparoscopic ovariohysterectomy (OHE) was performed on nine, healthy, intact female dogs using a Harmonic scalpel. Creatine kinase values were determined both before and 12 hours following the laparoscopic OHE; the magnitude of the difference between preoperative and postoperative creatine kinase values did not correlate with length of operative time, length of incisions, or amount of hemorrhage. Complications included one dog that had an omental herniation that was primarily repaired and one dog with seroma formation. Median surgical time for all dogs was 60 minutes (range, 35 to 100 minutes).

Microvascular free tissue transfer of the rectus abdominis muscle in dogs.

OBJECTIVE: To assess donor-site morbidity and survival of the rectus abdominis muscle with an overlying skin graft after free tissue transfer to a medial femorotibial defect in dogs. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Phase 1: 6 canine cadavers; phase 2: 7 adult mixed-breed dogs. METHODS: Phase 1: The rectus abdominis muscle was removed from canine cadavers, muscular and vascular dimensions were recorded, and angiography was performed. Phase 2: Muscular transfer was performed through anastomosis of the caudal epigastric artery and vein to the saphenous artery and medial saphenous vein. Transferred tissues were evaluated on postoperative days 3, 6, 10, and 13. Animals were examined daily until euthanasia between postoperative days 31 and 42. Postmortem angiograms were performed and tissues collected for histopathologic evaluation. RESULTS: Phase 1: Appropriate vascular dimensions for microvascular anastomosis were confirmed and surgical technique perfected. Phase 2: Muscular excision produced minimal donor-site morbidity. All muscles survived after microvascular transfer and angiography confirmed vascular patency. All of the skin grafts survived, with one graft undergoing partial necrosis. CONCLUSIONS: The rectus abdominis muscle can be successfully transferred to a medial femorotibial defect and can serve as a bed for acute skin grafting. No significant donor-site morbidity is associated with its removal. CLINICAL RELEVANCE: Microvascular free tissue transfer of the canine rectus abdominis muscle has not been previously described. This technique provides a new alternative for repair of appropriate wounds. Additional studies are needed to define its utility in clinical patients.

Evaluation of lameness associated with arthroscopy and arthrotomy of the normal canine cubital joint.

OBJECTIVE: To evaluate gait, range of motion (ROM), and lameness in normal dogs after arthroscopy or arthrotomy of the cubital joint. STUDY DESIGN: Experimental study. ANIMALS: Fourteen mature, healthy dogs. METHODS: Dogs were randomly assigned to treatment groups. Seven underwent arthrotomy and 7 underwent arthroscopy of the left cubital joint. Dogs were evaluated using kinetic gait assessment, subjective evaluation scores, and cubital joint ROM. Evaluations were performed before and on days 2, 4, 7, 15, 22, and 29 after surgery. Radiographs made before and after the surgical procedures were evaluated. RESULTS: Significant differences in peak vertical force and vertical impulse force were not observed between surgery groups (P =.88 and.49, respectively). Joint ROM was not significantly different between groups (P =.09 for flexion and.91 for extension). For all dogs, joint ROM and radiographic evaluations remained normal throughout the study period. Significant differences in subjective lameness scores, weight bearing, or pain were not observed between groups (P >/ or =.19 for all variables). CONCLUSIONS: In this study population, significant differences between dogs undergoing arthroscopy or arthrotomy of the cubital joint with respect to postoperative pain, weight bearing, joint ROM, or temporal improvement of ground reaction forces were not observed. CLINICAL RELEVANCE: The results of this study suggest that postoperative morbidity should not be a factor when making a decision to perform either arthroscopy or arthrotomy for exploration of the medial compartment of the canine cubital joint.