Comparison of 5 Surgical Techniques for Partial Liver Lobectomy in the Dog for Intraoperative Blood Loss and Surgical Time

Objective: To compare surgical time and intraoperative blood loss for 5 partial liver lobectomy techniques in the dog. Study Design: Experimental in vivo study. Animals: Dogs (n=10). Methods: Five surgical techniques (SurgiTie^?; LigaSure^?; Ultracision^® Harmonic Scalpel [UAS]; Suction+Clip; Suction+thoracoabdominal stapler [TA]) for partial liver lobectomy in dogs were evaluated and compared for total surgical time and intraoperative blood loss. Body weight, activated clotting time (ACT), heart rate, and intraoperative blood pressure (BP) were recorded. Blood loss was determined by adding the weight of the blood soaked sponges during surgery (1 g=1 mL) to the amount of suctioned blood (mL). Surgical time (in seconds) was determined from the start of the lobectomy until cessation of bleeding from the stump. Mean surgical time and mean blood loss for each technique were compared using a Tukey's multiple comparison test. Results: No significant differences were found between dogs for weight, ACT, heart rate, and intraoperative BP. No complications were seen with the SurgiTie^? technique in 9 of 10 cases. There was no significant difference in surgical time between techniques however there was a significant difference for blood loss; the Suction+Clip method had significantly more blood loss than the other techniques. Conclusions: Skeletonization of the lobar vessels before individually clipping them (Suction+Clip) resulted in a higher blood loss than using Suction+TA, UAS, SurgiTie^? or the LigaSure^? device. The SurgiTie^? appears to be an acceptable method for partial liver lobectomy. Clinical Relevance: Although skeletonization and individually clipping the vessels had the highest blood loss, it still was <7.5% of total blood volume. All 5 techniques should be safe for clinical use in small to medium sized dogs up to 26 kg.     

Relationships of Body Weight,Body Size,Subject Velocity,and Vertical Ground Reaction Forces in Trotting Dogs

Objective: To evaluate the relationship of body weight (BW) and size, dog velocity, and vertical ground reaction forces (GRF) from a large number of dogs of various sizes. Study Design: Clinical research. Animals: Orthopedically healthy dogs (n=129) Methods: BW and dog size, represented as height at the withers (WH), were obtained. Stance times (ST), vertical impulses (VI), and peak vertical forces (PVF) of thoracic and pelvic limbs were measured on a force plate at controlled trotting speed. They were evaluated against BW and WH using linear regression analysis in absolute (nonnormalized) values, and when normalized to BW and/or body size according to the theory of dynamic similarity. Relative velocities were calculated for each dog. Results: Absolute ST, VI, and PVF showed strong positive correlations with BW and/or body size. When GRFs were normalized to BW, correlations with body size were markedly reduced, but remained positive for VI, and turned negative for PVF. Normalizing the time‐dependent variables (ST and VI) also to WH eliminated most size influence. A small dependency of fully normalized GRF on body size remained that was because of differences in relative velocity between dogs of different sizes. Reference values for the fully normalized data are given. Conclusions: The inherent relationship between BW, body size, dog velocity, and vertical GRF was demonstrated. Clinical Relevance: BW, body size, and relative dog velocity must be accounted for when wanting to obtain GRF variables that are comparable between different dogs.     

Ex Vivo Comparison of Three Surgical Techniques to Stabilize Canine Cranial Cruciate Ligament Deficient Stifles

Objective— To quantify and compare canine stifle stability after 3 stabilization techniques. Study Design— Randomized controlled study. Sample Population— Adult canine cadaveric pelvic limbs. Methods— Total craniocaudal (CrCa) tibial translation quantified in stifles with the cranial cruciate ligament (CrCL) intact, transected, and stabilized with 1 of 3 techniques: (1) hamstring graft (HG); (2) modified retinacular imbrication (MRIT); (3) anatometric fascia lata translocation (AFLT). Tibial translation was quantified from radiographs generated during application of cranial and caudal forces to the tibia. After removal of all soft tissues except periarticular ligaments and fixation, CrCa tibial translation, as before, and medial–lateral rotation, via torsional loading, was quantified with an active motion analysis system. Total tibial translation was evaluated for effect of technique and cruciate status using mixed effect linear model with significance considered at P‐value <.05. Results— CrCa translation was not significantly different across stabilization techniques with CrCLs intact, transected, or after stabilization. Poststabilization translation was significantly less than posttransection for all techniques. Compared with the intact CrCL, CrCa translation poststabilization after HG was significantly greater whereas poststabilization after MRIT and AFLT was not significantly different. Tibial rotation exceeded instrumentation limits in 62.5% HG limbs, 20% MRIT limbs, and 60% AFLT limbs. Conclusions— All 3 stifle stabilization techniques confer comparable CrCa translational stability after CrCL disruption with that provided by the MRIT and AFLT techniques comparable to the intact CrCL. Clinical Relevance— The extra‐ and intracapsular techniques evaluated in this study reduced CrCa tibial translation in CrCL deficient stifles to varying amounts.     

Bending Characteristics of Polymethylmethacrylate Columns,Connecting Bars of Carbon Fiber,Titanium, and Stainless Steel Used in External Skeletal Fixation and an Acrylic Interface

Objective: To (1) mechanically evaluate polymethylmethacrylate (PMMA) columns of various sizes and compare them to connecting bar materials (carbon fiber composite, titanium, stainless steel) and (2) compare the properties of an intact PMMA column to those of an acrylic interface. Study Design: Experimental mechanical study. Sample Population: Experiment 1: 6 groups of 6 specimens each; experiment 2: 2 groups of 12 specimens each. Methods: All specimens were tested in 3‐point bending. Stiffness, yield strength, and ultimate strength values were calculated for each specimen. Results: PMMA 1 columns (23.25 mm) compared favorably to titanium or stainless‐steel bars. PMMA 3 columns (30.15 mm) and carbon fiber bars had similar yield strength but PMMA 3 columns were less stiff than carbon fiber bars. PMMA 3 columns had lower bending modulus and a higher variability in their mechanical properties than PMMA 1 or PMMA 2 (25.64 mm) columns. Acrylic interface specimens were less strong but as stiff as intact specimens. Conclusion: An acrylic interface was easily created and had acceptable biomechanical characteristics. Clinical Relevance: PMMA 2 and PMMA 3 columns are not recommended for clinical use at this time. Further tests are needed to analyze an acrylic patch in a more clinically relevant loading model.     

Continuous versus intermittent delivery of nutrition via nasoenteric feeding tubes in hospitalized canine and feline patients: 91 patients (2002–2007)

Objective – To compare continuous to intermittent feeding at delivering prescribed nutrition in hospitalized canine and feline patients. Design – Retrospective clinical study. Setting – University teaching hospital. Animals – Fifty‐four cats and 37 dogs. Measurements and Main Results – Twenty‐four‐hour periods of prescribed and delivered nutrition (kcal) were recorded, and the percentage of prescribed nutrition delivered (PPND) was calculated. If the patient received nasoenteric feeding for >1 day, then the average PPND per day was calculated. Frequency of gastrointestinal complications (vomiting, diarrhea, and regurgitation) was calculated per patient for each group. The PPND was not significantly different between patients fed continuously (99.0%) and patients fed intermittently (92.9%). Vomiting affected 29% of patients (26/91), diarrhea affected 26% of patients (24/91), and regurgitation affected 5% of patients (5/91). There was no significant difference in incidence of gastrointestinal complications between the patients fed continuously and the patients fed intermittently. There was a significantly higher incidence of diarrhea and regurgitation in dogs than in cats. Conclusions – PPND was not significantly different for continuous versus intermittent feeding via nasoenteric tubes. Frequencies of gastrointestinal complications were not significantly different between patients fed continuously and patients fed intermittently. Enterally fed dogs had a significantly higher frequency of regurgitation and diarrhea than enterally fed cats. Prospective studies are warranted to investigate causes for these potential inter‐species differences.     

Thyroxine concentrations are elevated in mares which continue to exhibit estrous cycles during the nonbreeding season

In two successive years, the pattern of secretion of thyroxine was compared in seasonally anestrous mares and a subpopulation of mares that exhibited estrous cycles during the nonbreeding season. Blood samples were collected two or three times per week between October and April from a total of 15 mares that exhibited estrous cycles during the nonbreeding season and 21 anestrous mares. Monthly mean concentrations of thyroxine during the period from October through April were greater (p<0.05) in cycling versus anestrous mares. However, it remains to be determined whether continuation of estrous cycles during the nonbreeding season and elevated concentrations of thyroxine are causally related.