Saline Volume Necessary to Achieve Predetermined Intraluminal Pressures during Leak Testing of Small Intestinal Biopsy Sites in the Dog

Objective: To determine the volume of saline needed to achieve targeted intraluminal pressures during leak testing of closed jejunal biopsy sites in the dog. Study Design: Experimental. Animals: Dogs (n=38). Methods: Jejunal biopsies in dogs were performed and closed using 3–4 full thickness simple interrupted sutures. Saline volumes needed to achieve 2 predetermined intraluminal pressures (20 and 34 cm water [15 and 25 mmHg]) in a 10 cm canine jejunal segment containing a closed biopsy site using 2 methods of luminal occlusion were recorded. Results: The 95% confidence intervals for the volume of saline needed to achieve 20 and 34 cm water intraluminal pressure were 10.9–13.6 and 16.3–19.0 mL, respectively with digital occlusion and 8.5–11.1 and 12.1–14.8 mL, respectively with Doyen occlusion. Correlation between volume of saline instilled and the pressure achieved was 0.76 for digital occlusion and 0.86 for Doyen occlusion. Conclusion: Correlation between volume of saline instilled and pressure achieved was greater with Doyen than digital occlusion. Clinical Relevance: For canine jejunum, saline volumes of 16.3–19 mL (digital occlusion) and 12.1–14.8 mL (Doyen occlusion) can be used to achieve intraluminal pressures of 34 cm water during leak testing of a 10 cm segment containing a closed biopsy site.     

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.     

Juvenile Pubic Symphysiodesis and Juvenile Pubic Symphysiodesis Associated with Pectineus Myotomy: Short‐Term Outcome in 56 Dysplastic Puppies

Objectives— (1) To compare short‐term outcome of juvenile pubic symphysiodesis (JPS) in puppies aged 12–17 weeks with lax hips (group JPS1), in puppies aged 18–22 weeks (group JPS2), and control (group C) puppies; and (2) to document outcome of bilateral pectineus myotomy (PM) associated with JPS in 18–22‐week‐old puppies (group JPS–PM). Study Design— Prospective study. Methods— Puppies (12–22 weeks) from large and giant breed dogs with a combination of a positive Ortolani sign, poor acetabular coverage (Norberg angle [NA]≤100°), and a subluxation index (SI) >0.5 for one or both hips were selected. Puppies aged <18 weeks were randomly assigned to group JPS1 or C. Puppies aged 18–22 weeks were randomly assigned to group JPS2, JPS–PM, or C. Three to 4 months later, surgery was considered successful in pain‐free dogs with negative Ortolani sign, normalized acetabular coverage (NA≥105°), and SI>0.5. Success rates were compared using Fisher's exact tests: JPS1 versus JPS2 versus C; JPS2 versus JPS–PM. Significance was set at P<.05. Results— All dysplastic hips from nonoperated (C) groups were dysplastic at follow‐up, meaning that our criteria for case selection were accurate. JPS1 had significantly better success rate than JPS2 (85 versus 17.8%, respectively). JPS–PM dysplastic hips failed to demonstrate a better outcome than JPS2 hips. Clinical Relevance— This study confirms, on a large series of dysplastic hips, the age‐dependent effects of JPS, with better results if performed before 18 weeks of age. There is no benefit of adding PM to the procedure in candidates >18 weeks at surgery.     

The Effect of Six Knotting Methods on the Biomechanical Properties of Three Large Diameter Absorbable Suture Materials

Objective— To evaluate the effect of 6 different knotting methods on the mechanical properties of 3 large absorbable suture materials used in large animal surgery. Study Design— In vitro mechanical study. Sample Population— Knotted suture loops (n=15 per group). Methods— Suture loops were created between two low‐friction pulleys with either 2 polydioxanone, 2 polyglactin 910 or 3 polyglactin 910. Strands were tied using 1 of 6 knotting technique: square knot, surgeon knot, clamped surgeon's knot, sliding half‐hitch knot (HH), Delimar knot and self‐locking knot (SLK). A single cycle to failure test was performed on each suture loop with a distraction rate of 100 mm/min. Failure modes were evaluated and breaking strength, elongation to failure and stiffness were compared. Results— All loops except two HH failed at the knot by acute breaking. The double‐stranded SLK was both stronger and stiffer than all other knots for each suture material. Clamping the first throw of the surgeon knot decreased load to failure significantly (143.11 ± 8.64 N) compared with not clamping (159.21 ± 6.14 N) for polydioxanone. Stiffness and elongation to failure were respectively lower and increased for 2 polydioxanone compared with both polyglactin 910 materials for all knotting techniques. Conclusions— Knotting techniques do influence structural properties of suture loops. The double strand loop conferred stiffer and stronger properties to the SLK Clinical Relevance— Clamping the first throw of polydioxanone should be avoided when tying a suture under tension even using large diameter suture materials. Using a SLK might be considered as a useful alternative when excessive tension is present.     

Mechanical Evaluation of Hydrogen Peroxide Gas Plasma Sterilization of Nylon Lines Used for Extra-Articular Stabilization of the Canine Stifle Joint

Objective— To compare the effects of hydrogen peroxide gas plasma (HPGP) and ethylene oxide (EO) sterilizations on the mechanical properties of nylon lines used for stabilization of the canine stifle. Secondarily, to compare the performance of crimped and knotted lines.
Study Design— In vitro mechanical evaluation.
Sample Population— Nonsterilized, EO- and HPGP-sterilized specimens of 36.3 kg test nylon leader line (NLL) and 57.8 kg test nylon fishing line (NFL).
Methods— Single strands and looped specimens of NLL or NFL were positioned on a material testing machine. To create looped specimens, NLL were crimped using the Securos system, and NFL were knotted, as used clinically. Elongation (%) and ultimate load (N) variables were studied.
Results— Elongation and ultimate load of NLL groups were not significantly different between EO and HPGP. For NFL, HPGP sterilization led to slightly greater elongation than EO in loops only. Ultimate load of NFL single strands was not significantly different between EO and HPGP, but was higher after HPGP compared with EO in NFL loops. All NLL groups had less elongation and ultimate load than NFL.
Conclusion— The effects of HPGP on NLL compared positively to EO, making HPGP an attractive alternative. As HPGP led to a slightly greater elongation of NFL than EO, the latter could be favored to sterilize NFL. Crimped NLL minimized elongation better than knotted NFL.
Clinical Relevance— Sterilization with HPGP seems a good alternative to EO for NLL. EO may be a better choice for NFL; however, it is difficult to judge the clinical relevance of this result. Crimped NLL minimizes elongation and may help reducing the recurrence of stifle instability postoperatively.     

Arthrodesis of the Equine Proximal Interphalangeal Joint: A Biomechanical Comparison of Two 7-Hole 3.5-mm Broad and Two 5-hole 4.5-mm Narrow Dynamic Compression Plates

OBJECTIVE: To compare the biomechanical characteristics and mode of failure of two different dynamic compression plate (DCP) techniques for proximal interphalangeal joint (PIPJ) arthrodesis in horses. STUDY DESIGN: Randomized block-design blocking on horse (1-5), method of fixation (two 7-hole, 3.5-mm broad DCP vs two 5-hole, 4.5-mm narrow DCP), side (left, right), and end (front, hind). Constructs were loaded to failure in 3-point bending in a dorsal-to-palmar (plantar) direction. SAMPLE POPULATION: Ten paired limbs from 5 equine cadavers. METHODS: Two 7-hole, 3.5-mm broad dynamic compression plates (bDCP) were used in 1 limb of a pair, and two 5-hole 4.5-mm narrow dynamic compression plates (nDCP) were used on the contralateral limb. Plates were positioned abaxially across the dorsomedial and dorsolateral aspect of the PIPJ. Arthrodesis constructs were loaded (19 mm/s) in 3-point bending in a dorsal-to-palmar (plantar) direction using a materials-testing machine. Composite stiffness, yield point, and maximal bending moment at failure were obtained from bending moment-angular deformation curves. Data were analyzed using ANOVA, X(2) analysis, and Fisher's exact tests; the power of the test was calculated when differences were not significant. RESULTS: There were no significant differences in composite stiffness (P >.05; power = 0.8 @ delta = 21.9%), yield point (P >.05; power = 0.8 @ delta = 34.4%), or maximal bending moment (P >.05; power = 0.8 @ delta = 17.8%) between the two fixation techniques. For bDCP constructs, 11% (15 of 140) of the 3.5-mm screws were damaged; 7 of the screw heads pulled through plates where the plates bent, 1 screw head broke off, and 7 screws were bent or pulled out of the phalanx. For nDCP constructs, 8% (8 of 100) of the 4.5-mm screws were damaged; 1 screw head pulled through a plate, 1 screw head broke off, and 6 screws were bent or pulled out of the phalanx. CONCLUSIONS: There were no biomechanical or failure differences between bDCP and nDCP fixation of the PIPJ in horses when evaluated in single-cycle 3-point bending to failure. CLINICAL RELEVANCE: There is no biomechanical advantage to the use of two 7-hole, 3.5-mm bDCP in equine proximal interphalangeal arthrodesis compared with two 5-hole, 4.5-mm nDCP. Two 5-hole, 4.5-mm nDCP may be easier to place, whereas two 7-hole, 3.5-mm bDCP may provide more versatility in fracture repair.     

Butorphanol Tartrate for Partial Reversal of Oxymorphone-Induced Postoperative Respiratory Depression in the Dog

A randomized, blinded, crossover study was designed to evaluate the respiratory, cardiovascular, and behavioral effects of butorphanol given postoperatively to oxymorphone-premedicated and surgically stimulated dogs. Nine healthy adult dogs were premedicated intramuscularly with atropine (0.04 mg/kg), acepromazine (0.10 mg/kg), and oxymorphone (0.2 mg/kg). Anesthesia was induced with thiamylal (12 mg/kg) and maintained with halothane in oxygen. According to the protocol of a concurrent study, all dogs had percutaneous endoscopic gastrostomy (PEG) feeding tubes placed during the first anesthetic episode and removed during the second anesthetic episode. All dogs received postoperatively either butorphanol tartrate (0.2 mg/kg) or an isovol-umetric dose of saline placebo, both given intravenously. Respiratory rate (RR), tidal volume (TV), minute ventilation (MV), end-tidal CO₂ concentration (ET_CO2). heart rate (HR), and indirect diastolic (DP), systolic (SP) and mean arterial (MAP) blood pressures were measured at times 0, 2, 5, 10, 20, 40, 80, and 120 minutes after injection. The time from injection of the test drug until extubation was recorded. RR, MV, HR, and DP were significantly ( P < .05) increased, while ET_co2 was significantly decreased, for a minimum of 30 minutes in butorphanol-treated dogs compared with saline controls. TV, SP, and MAP were transiently (≤15 minutes) increased in butorphanol-treated dogs compared with saline controls. There was no significant difference between the times to extubation in the butorphanol-treated dogs versus the saline control dogs.