Evaluation of the in vitro performance of the double forwarder knot, compared to square and surgeon's knots using large gauge suture.

OBJECTIVE: The aim of the study was to evaluate the strength and size of the double forwarder (DF) knot in 2 and 3 USP polyglactin 910 when used to form a ligature and to compare the knot holding capacity (KHC), size and weight of the DF knot to surgeon's (SU) and square (SQ) knots with varying numbers of throws. STUDY DESIGN: Laboratory study. STUDY POPULATION: Knotted suture. METHODS: Knots were tied using 2 and 3 USP polyglactin 910 and tested on a universal testing machine under linear tension. Mode of failure and (KHC) were recorded. Knot volume and weight were determined by digital micrometer and balance. KHC, size, and weight between knot type, number of throws, and suture type and size were compared using ANOVA testing, with p < .05 as significant. RESULTS: In both suture types, DF knots had a higher KHC than SQ/SU knots (p < .004), with the exception of SU knots with 6-8 throws in 3 USP polyglactin 910 (p > .42). All DF knots failed by suture breakage at the knot, as did all SQ/SU knots with >6 throws. DF knots in 2 and 3 USP polyglactin 910 were larger and heavier than SQ and SU knots when the same number of throws was applied (p < .003). CONCLUSION: Self-locking DF knots provided increased strength compared to SU/SQ in large gauge suture but only when fewer than six throws are applied to SU/SQ knots. CLINICAL RELEVANCE: The new DF knot could be an alternative for a secure ligature.

Concurrent versus delayed exposure to corticosteroids in equine articular tissues cultured with local anesthetic.

OBJECTIVE: To determine the effect of concurrent versus delayed treatment with corticosteroid on equine articular tissues also treated with local anesthetic in vitro in the presence of inflammatory mediators. STUDY DESIGN: Controlled laboratory study. ANIMALS: Five geldings, one mare (aged 3-18 years). METHODS: From each horse, 24 synovial and 12 osteochondral explants were cultured in a 12-well plate (2 wells/group, 2 synovial and 1 osteochondral explant/well, total 216 explants in the study). Explants were stimulated in culture medium with 10 µg/ml recombinant equine interleukin-1ß and 10 µg/ml tumor necrosis factor-α for 48 hours, then randomly assigned to six treatments: unstimulated control, stimulated control, triamcinolone acetonide (TA, 10-6  M), mepivacaine hydrochloride (MH, 4.4 mg/ml), MH + TA (concurrent) and MH + TA (delayed). The delayed group was treated with MH and, 6 days later, treated with TA. Every 3 days for 9 days total, medium levels of lactate dehydrogenase (LDH), prostaglandin E2 (PGE2 ), matrix metalloproteinase 13 (MMP-13) and glycosaminoglycan (GAG) were quantified via ELISA. Data were analyzed with mixed-effects models with Tukey's multiple comparisons. RESULTS: Stimulation increased medium PGE2 and MMP-13 and had no effect on LDH or GAG. Treatment with MH increased LDH and decreased PGE2 and MMP-13. Treatment with TA decreased PGE2 and MMP-13. CONCLUSION: There were no differences in cytotoxicity, inflammation or matrix degradation for delayed or concurrent MH and TA treatment groups up to 9 days in culture. CLINICAL SIGNIFICANCE: The lack of an effect of concurrent versus delayed treatment might indicate that concurrent therapy is acceptable.

The Effect of Inhaled Albuterol on PaO2 in Anesthetized Horses Receiving a FiO2 of 0.5 or >0.95.

Impairment of oxygen uptake can occur during general anesthesia in horses resulting in hypoxemia. Multiple treatments have been investigated for correction of hypoxemia with varying levels of success. In clinical trials, albuterol, a short-acting ß2 adrenergic agonist, improved arterial oxygen partial pressure (PaO2) in anesthetized horses unresponsive to adjustments in mechanical ventilation and administration of positive inotropic drugs. However, controlled studies comparing the magnitude of change and duration of effect of albuterol on PaO2 in healthy, nonhypoxemic anesthetized horses are lacking. In a prospective study, 14 horses were anesthetized and received a FiO2 of 0.5 (n = 7) or > 0.95 (n = 7). Horses were maintained on isoflurane and mechanically ventilated. After 15 minutes, baseline PaO2 was determined. Within each FiO2 group, five horses were administered inhaled albuterol (2 µg/kg) and two horses received no treatment. At 10, 20, 30, and 40 minutes after baseline, PaO2 was measured. Data for horses that received albuterol were analyzed with repeated measures analysis of variance with significance at P < .05. Horses that received albuterol had an increase in PaO2 for at least 40 minutes after baseline. Albuterol administered via inhalation, was associated with an increased PaO2 of at least 40 minutes compared to baseline in healthy, nonhypoxemic horses undergoing anesthesia at similar depth, using a FiO2 of 0.5 and > 0.95. Side effects were mild and consisted of increased heart rate and sweating. Albuterol administered at 2 µg/kg via inhalation may be useful for increasing PaO2 in anesthetized horses.

Hybrid natural orifice transluminal endoscopy surgery (NOTES) to perform bilateral ovariectomy in mares.

OBJECTIVES: To combine laparoscopic techniques with natural orifice transluminal endoscopic surgery (hybrid NOTES) to minimize number and enlargement of paralumbar laparoscopic portals for bilateral ovariectomy in standing, sedated mares. STUDY DESIGN: Case series. ANIMALS: Six horses. MATERIALS AND METHODS: Six mares with palpably normal ovaries were restrained in stocks, sedated, and had caudal epidural anesthesia performed. A 7.5 MHz ultrasound probe was used transvaginally to select placement of vaginotomy. An attempt was made to remove both ovaries with 70 cm esophageal forceps through the vaginotomy, while visualized and transected via ipsilateral paralumbar fossa laparoscopic portals. Surgical time, intraoperative, and postoperative complications were recorded. Vaginoscopy was performed at days 0, 3, 7, and 14 postoperatively. After 14 days, mares were euthanized and necropsied. RESULTS: Hybrid NOTES allowed successful bilateral ovariectomy in all six mares, with a mean surgical time of 70 ± 25 min. In two mares, one ovary was dislodged from the forceps during vaginotomy extraction. Abdominal retrieval of the ovary was successful with reapplication of forceps or a surgeon's hand via vaginotomy. At necropsy, five mares had no adhesions within the abdominal cavity or at the vaginotomy site. One mare in which hand retrieval of the ovary was necessary, developed an adhesion between the bladder and the vaginotomy. CONCLUSIONS: This technique appears to offer a safe alternative for bilateral ovariectomy with minimal postoperative complications. CLINICAL SIGNIFICANCE: Decreased number and size of paralumbar laparoscopic incisions could decrease complications associated with exteriorization of ovaries through the flank.

Ex vivo comparison of the bursting strength of an equine ventral midline celiotomy covered by two standard abdominal bandages.

OBJECTIVE: To determine the compressive effect of abdominal bandages after ventral midline celiotomy closure in horses. STUDY DESIGN: Ex vivo, experimental study. ANIMALS: Equine cadavers (n = 18), six per group. METHODS: A 20-cm ventral midline celiotomy was created in each of 18 equine cadavers. A 200-L inflatable bladder was placed in the abdomen, and the linea alba was apposed. Horses were randomly assigned to no bandage (C), elastic (E), or Velcro inelastic (I) bandage groups for testing. Circumferential bandages were placed with a subbandage pressure monitoring system over the incision. The bladder was insufflated until construct failure, which was determined by a decrease in pressure reading. Bursting pressure, location of body wall or bandage failure, and subbandage pressures were recorded. RESULTS: Maximum bursting pressure was different between groups E and C (P = .004), with no difference between groups E and I (P = .146) or I and C (P = .085). Group I achieved higher subbandage pressure compared with group E (P = .036). Abdominal compliance was not different between groups (P = .099). Location of failure differed between groups (P = .011), with failure at the diaphragm more common in group I (6/6, 100%) compared with groups E (3/6 [50%]) and C (1/6 [16.7%]). CONCLUSION: Elastic abdominal bandages had higher abdominal bursting pressures compared with unbandaged incisions.

Evaluation of the effects of medial saphenous venous pressures as an indirect method of measurement of intra-abdominal pressures in the horse.

OBJECTIVE: To evaluate the effect of changes in intra-abdominal pressure (IAP) on medial saphenous venous pressure (MSVP) and hemodynamics in normal horses. DESIGN: Experimental, in-vivo study. SETTING: University Teaching Hospital. ANIMALS: Convenience sample of 7 mixed breed horses; 5 geldings, and 2 mares. INTERVENTIONS: Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20 mm Hg over 30 minutes, and maintained at that pressure for 30 minutes to evaluate the effect of sustained intra-abdominal hypertension. The MSVP and vital parameters were recorded, along with direct arterial blood pressure from the transverse facial artery. MEASUREMENTS AND MAIN RESULTS: As IAP increased, MSVP increased in a stepwise manner, in concert with changes in IAP. The consistency in measurement between MSVP and IAP was high (intraclass correlation coefficient = 0.92; P < 0.001) and repeated measures correlation was excellent (r = 0.98; P < 0.001). Heart rate was unchanged over the course of the experiment (P = 0.09), however, respiratory rate increased with increasing IAP (P < 0.001). Arterial blood pressure also increased with insufflation (P < 0.001), with a significant difference at an IAP of 15 mm Hg (P = 0.04). CONCLUSIONS: This report provides preliminary data demonstrating a strong correlation between equine MSVP and changes in IAP, similar to that observed in other species. Further investigations are needed to evaluate this relationship, and to confirm these results in clinical patients.

In vitro evaluation of the modified forwarder knot used to end a continuous suture pattern in large-gauge suture.

OBJECTIVE: To evaluate the strength and size of forwarder end (FE) knots modified to end continuous suture lines compared with Aberdeen (AB), square (SQ), and surgeon's (SU) knots. STUDY DESIGN: In vitro mechanical study. STUDY POPULATION: Knotted suture. METHODS: Knots were tied with 2 USP (United States Pharmacopeia) polydioxanone, 2 USP, and 3 USP polyglactin 910 and tested on a universal testing machine under linear tension. Mode of failure and knot holding capacity (KHC) were recorded, and relative knot security (RKS) was calculated. Knot volume and weight were determined by digital micrometer and balance. Knot holding capacity, RKS, size, and weight between knot type, number of throws, and suture type and size were compared by using analysis of variance testing, with P < .05 considered significant. RESULTS: In all suture types and number of throws, FE knot KHC/RKS was 28% to 66.99% (1.2-1.6 fold) stronger compared with SQ/SU knots (P < .001). For 2 USP polydioxanone, FE knots had 10% (1.1 fold) higher KHC/RKS compared with AB knots (P < .042). However, in 2 and 3 USP polyglactin 910, FE knot KHC/RKS values were not different from those of AB knots (P > .080). Forwarder end/AB knots failed by suture breakage at the knot, whereas some SQ/SU knots unraveled. Forwarder end knots in 2 and 3 USP polyglactin 910 were 21.1% to 44.4% (1.2-1.4 fold) smaller compared with SQ/SU knots (P < .028). Forwarder end knots in 2 and 3 USP polyglactin 910 were 40% to 99% (1.4-2.0 fold) larger compared with AB knots (P < .001). CONCLUSION: Forwarder end knots provided increased KHC/RKS compared with SQ/SU knots. CLINICAL RELEVANCE: Forwarder end knots should be considered for closures when suture is placed under tension.

Evaluation of the effects of intraabdominal hypertension on equine central venous pressure.

OBJECTIVE: To evaluate the effect of changes in intraabdominal pressure (IAP) on central venous pressure (CVP) in normal horses. DESIGN: Experimental, in vivo study. SETTING: University Teaching Hospital. ANIMALS: Convenience sample of 7 mixed breed horses-5 geldings and 2 mares. INTERVENTIONS: Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20 mm Hg over 30 minutes, and maintained at that pressure for 30 minutes to evaluate the effect of sustained intraabdominal hypertension. CVP was obtained from the cranial vena cava, concurrent with pressure obtained from the peritoneal cavity. MEASUREMENTS AND MAIN RESULTS: CVP increased as IAP increased up to 12 mm Hg, and declined as IAP increased further. The changes in CVP over time were significantly different (P < 0.03). Repeated measures correlation was positive, and highest, for mean CVP as IAP increased from 0 to 12 mm Hg (r = .70; 95% CI, .43-.85; P < 0.0001). Correlation of mean CVP with insufflation pressure became negative as IAP increased further from 15 to 20 mm Hg (r = -.47; 95% CI, -.66 to -.21; P = 0.0006). CONCLUSIONS: This report provides preliminary data demonstrating a biphasic trend in equine CVP caused by changes in IAP, similar to that observed in other species. Further investigations are needed to evaluate this trend and to confirm these results in clinical patients.

Tensile strength and early healing of self-locking and surgeon's knots.

OBJECTIVE: To compare the biomechanical properties and healing of ventral midline celiotomies (VMC) closed with a self-locking knot combination and forwarder start and Aberdeen end (F-A) vs a traditional knot combination and surgeon's start and end (S-S). STUDY DESIGN: In vivo, experimental. ANIMALS: Twenty-one horses. METHODS: Fourteen horses underwent VMC, which was closed with either an F-A (n = 7) or an S-S (n = 7) knot combination. Incisions were subjectively graded by masked evaluators for dehiscence, edema, and drainage. Biomechanical testing was performed on three abdominal segments, and histology was performed on one segment from each animal after humane euthanasia 10 days post-VMC. The abdominal wall of control horses (n = 7, no celiotomy) was collected for biomechanical testing. RESULTS: Forwarder start and Aberdeen end and S-S horses had less tensile strength compared with control horses (P ≤ .001). No differences were detected between treatment groups for any variable evaluated, including tensile strength (P = .975), location of failure (P = .240), and histologic healing at the knot (P = .600). CONCLUSION: Closure of VMC with self-locking knots resulted in biomechanical and healing features similar to those with a traditional closure technique, with neither restoring the tensile strength of the linea alba. CLINICAL SIGNIFICANCE: Results of this study provide evidence to support a clinical trial to evaluate long-term performance of the F-A self-locking knot closure in horses.

Comparison Between the Hyperelastic Behavior of Fresh and Frozen Equine Articular Cartilage in Various Joints.

Fresh and frozen cartilage samples of the fetlock, carpus, and stifle were collected from 12 deceased horses. Half were measured immediately following extraction, and half were frozen for seven days and then measured. Seven indentations (various normalized displacements) were implemented with an indention rate of 0.1 mm/s. Solid phase aggregate modulus (Es), hyperelastic material constant (α), and fluid load fraction (F') of equine articular cartilage were assessed using the Ogden hyperelastic model. The properties were statistically compared in various joints (fetlock, carpus, and stifle), and between fresh and frozen samples using various statistical models. There was no statistical difference between the fetlock and carpus in the aggregate modulus (p = 0.5084), while both were significantly different from the stifle (fetlock: p = 0.0017 and carpus: p = 0.0406). For the hyperelastic material constant, no statistical differences between joints were observed (p = 0.3310). For the fluid load fraction, the fetlock and stifle comparison showed a difference (p = 0.0333), while the carpus was not different from the fetlock (p = 0.1563) or stifle (p = 0.3862). Comparison between the fresh and frozen articular cartilage demonstrated no significant difference among the joints in the three material properties: p = 0.9418, p = 0.7031, and p = 0.9313 for the aggregate modulus, the hyperelastic material constant, and the fluid load fraction, respectively.

Phaeohyphomycotic Rhinitis Caused by Bipolaris hawaiiensis in a Horse.

This case represents the first reported case of Bipolaris hawaiiensis infection in an equid, and its aggressive clinical course. This case provides important descriptive and prognostic information for horses diagnosed with phaeohyphomycotic rhinitis. A 19-year-old American Quarter Horse mare was presented for second opinion of stertor and exercise intolerance of four-month duration. Endoscopy revealed generalized, proximal nasal edema, and computed tomography identified a soft tissue mass eroded through the rostral nasal bone. Biopsy of the mass was identified as a fungal granuloma caused by B. hawaiiensis resulting in chronic invasive fungal rhinitis. Treatment options were limited because of invasive infection, financial constraints, fungal sensitivity results, and published accounts of in vivo behavior of the organism. The infection progressed, resulting in euthanasia. In this case of equine phaeohyphomycosis, B. hawaiiensis was likely traumatically introduced into the patient's nasal cavity. Its aggressive nature in an apparently immunocompetent patient is noteworthy, in the face of surgical debridement and attempted medical therapy. Therapeutic decisions were challenging in this case based on limited in vivo efficacy data in equids, pharmacokinetic challenges with available antifungal agents, and client-driven limitations regarding management of airway restriction.

In vitro evaluation of the knot-holding capacity and security, weight, and volume of forwarder knots tied with size-3 polyglactin 910 suture exposed to air, balanced electrolyte solution, or equine abdominal fat.

OBJECTIVE: To evaluate the effect of exposure to a balanced electrolyte solution (BES), or equine abdominal fat on the knot-holding capacity (KHC), relative knot security (RKS), weight, and volume of forwarder knots versus surgeon's knots. SAMPLE: 315 knots tied and tested in vitro. PROCEDURES: United States Pharmacopeia size-3 polyglactin 910 suture exposed to air (dry [control]), equine abdominal fat (fat-exposed), or BES (BES-exposed) was used to tie forwarder knots with 2, 3, and 4 throws and surgeon's knots with 5, 6, 7, and 8 throws. A universal materials testing machine was used to test the tensile strength of suture and knots to failure, and the KHC, RKS, weight, and volume of knots were determined. RESULTS: Forwarder knots had significantly higher KHC and RKS and lower volume, compared with surgeons' knots. Forwarder knots tied with fat-exposed suture had greater weight, but not volume, than did forwarder knots tied with dry or BES-exposed suture with the same number of throws. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that forwarder knots were superior to surgeon's knots when configured as start knots intended for continuous lines of suture. Exposure to media did not negatively affect mechanical or physical properties of forwarder knots and may improve specific biomechanical functions, including KHC and RKS.

Bursting strength of surgeon's and self-locking knots for closure of ventral midline celiotomy in horses.

OBJECTIVE: To compare the bursting strength and failure mode of ventral midline celiotomy closed with a simple continuous suture pattern with 1 of 2 knot combinations, a novel self-locking knot combination of a forwarder start with an Aberdeen end knot (F-A) and a traditional combination of a surgeon's start with a surgeon's end knot (S-S). STUDY DESIGN: Ex vivo experimental. SAMPLE POPULATION: Equine cadavers (n = 14). METHODS: A 20-cm ventral midline celiotomy was created in 14 equine cadavers. Horses were assigned to celiotomy closure with an F-A or S-S knot combination. Prior to closure, a 200-L inflatable bladder was placed in the abdomen and then insufflated until failure of the celiotomy closure. The horses' signalment, weight, breed, and age, as well as knot combination type, mode of failure, closure time, and bursting strength (mm Hg) were recorded. RESULTS: The median bursting strength was significantly greater when incisions were closed with the F-A knot combination (388 mm Hg) compared with the S-S knot combination (290 mm Hg) (P = .035). Most incisions failed along the fascia when closed with F-A combinations and at the knot when closed with S-S combinations. CONCLUSION: The bursting strength of ventral midline incisions in equine cadavers was increased by an average of 25% when closed with the self-locking F-A knot combination. CLINICAL SIGNIFICANCE: Closing ventral midline celiotomies with an F-A knot combination may provide a more secure closure than the traditional S-S knot combination. Additional in vivo investigation is required prior to recommending this closure in clinical cases.

Medical Therapy in Equine Wound Management.

Suitable use of prophylactic antimicrobial drugs for wounds depends on the accurate selection of appropriate antibiotics, dosing regimen, and duration of use. Regional intravenous delivery and intraosseous infusion of antibiotics are pivotal to a successful outcome for deep-rooted infections, inadequately perfused tissue, and infected wounds containing biofilm. Antibiotic-impregnated polymethylmethacrylate beads are predominantly helpful for wounds that have a poor blood supply and for those containing surgical implants that must remain in place.

In vitro evaluation of square and surgeon's knots in large gauge suture.

OBJECTIVE: To investigate the strength and size of surgeon's and square knots for starting and ending continuous suture lines using large gauge suture. STUDY DESIGN: In vitro mechanical study. STUDY POPULATION: Knotted suture. METHODS: Surgeon's and square knots were tested using 2 and 3 USP polyglactin 910 and 2 USP polydioxanone under linear tension on a universal testing machine. Failure mode and knot holding capacity (KHC) were recorded, and relative knot security (RKS) was calculated as a percentage of KHC. Comparisons were made between number of throws, suture size, suture type, and knot types. Knot volume and weight were assessed by a digital micrometer and balance, respectively. RESULTS: There were no significant differences in KHC (P = .295), RKS (P = .307), volume (P = .128), or weight (P = .310) between square and surgeon's knots at the start or end of suture lines with the same number of throws and suture type. A minimum of 6 throws were required for start knots and 7 throws at end knots to prevent unraveling. Knots tied with 3 polyglactin 910 were strongest (P < .001) and 2 polyglactin 910 produced knots with higher KHC and RKS than 2 polydioxanone (P < .001). CONCLUSION: No consistent differences were detected between knots types tied with the same suture material; however, number of throws affected KHC and RKS up to 6 throws in start or 7 throws in end knots. The configuration of square and surgeon's knots performed at the end of a continuous line alters their KHC, supporting the use of additional throws for knot security.

Effect of fluid media on the mechanical properties of continuous pattern-ending surgeon's, square, and Aberdeen knots in vitro.

OBJECTIVE: To investigate the knot holding capacity (KHC) of pattern-ending square, surgeon's and Aberdeen knots each tied in 4 throw combinations using large gauge suture after exposure to media commonly found in equine abdominal surgery. STUDY DESIGN: In vitro mechanical study. SAMPLE POPULATION: Knotted suture strands (n = 10/group). METHODS: Strands of 2 polydioxanone or 3 polyglactin 910 were exposed to 1 of 4 media for 15 minutes. Control suture strands remained dry. Media used included balanced electrolyte solution, 1% sodium carboxymethylcellulose, equine serum, or equine fat. Pattern-ending knots for the 3 knot configurations were loaded to failure in a linear fashion on a materials testing machine to determine KHC. RESULTS: Surgeon's knots tied using media-exposed 3 polyglactin 910 had a significantly higher KHC than the same dry knots with 5 and 6 throws. Square knots tied using media-exposed to 3 polyglactin 910 had a significantly higher KHC than the same dry knots at 5 throws. Aberdeen knots tied with either media-exposed 2 polydioxanone or 3 polyglactin 910 had a significantly higher KHC than their equivalent dry knots. Aberdeen knots had a superior KHC, while requiring less suture than both surgeon's and square knots. CONCLUSION: Media exposure either had no effect on KHC or significantly improved the KHC of all knots investigated. Based on KHC and knot volume, Aberdeen knots tied using media-exposed 3 polyglactin 910 with 3 throws and 1 turn are recommended to end a continuous suture pattern.

In Vitro Evaluation of the Size, Knot Holding Capacity, and Knot Security of the Forwarder Knot Compared to Square and Surgeon's Knots Using Large Gauge Suture.

OBJECTIVE: To investigate the strength, size, and holding capacity of the self-locking forwarder knot compared to surgeon's and square knots using large gauge suture. STUDY DESIGN: In vitro mechanical study. STUDY POPULATION: Knotted suture. METHODS: Forwarder, surgeon's, and square knots were tested on a universal testing machine under linear tension using 2 and 3 USP polyglactin 910 and 2 USP polydioxanone. Knot holding capacity (KHC) and mode of failure were recorded and relative knot security (RKS) was calculated as a percentage of KHC. Knot volume and weight were assessed by digital micrometer and balance, respectively. ANOVA and post hoc testing were used tocompare strength between number of throws, suture, suture size, and knot type. P<.05 was considered significant. RESULTS: Forwarder knots had a higher KHC and RKS than surgeon's or square knots for all suture types and number of throws. No forwarder knots unraveled, but a proportion of square and surgeon's knots with <6 throws did unravel. Forwarder knots had a smaller volume and weight than surgeon's and square knots with equal number of throws. The forwarder knot of 4 throws using 3 USP polyglactin 910 had the highest KHC, RKS, and the smallest size and weight. CONCLUSION: Forwarder knots may be an alternative for commencing continuous patterns in large gauge suture, without sacrificing knot integrity, but further in vivo and ex vivo testing is required to assess the effects of this sliding knot on tissue perfusion before clinical application.

Use of a Barbed Knotless Suture for Laparoscopic Ablation of the Nephrosplenic Space in 8 Horses.

OBJECTIVE: To evaluate use of a knotless suture for laparoscopic closure of the equine nephrosplenic space. STUDY DESIGN: Experimental in vivo study. ANIMALS: Normal horses without previous history of abdominal surgery (n=8). METHODS: The nephrosplenic space was closed under laparoscopic visualization using a unidirectional, barbed 0 metric absorbable suture (copolymer of glycolic acid and trimethylene carbonate). Intracorporeal suturing of the nephrosplenic space was performed in a cranial-to-caudal direction in a simple continuous fashion. Repeat evaluation was performed laparoscopically in 2 horses and by necropsy in 6 horses. The length of closure was measured and nature of the healed tissue was evaluate grossly. RESULTS: Total surgery time was 65-167 minutes (mean ± SD, 89.6 ± 22.6). Suturing time was 30-65 minutes (40.4 ± 16.3). Second laparoscopy in 2 horses was performed at days 198 and 227. Necropsy was performed at day 69-229 postoperatively (132.7 ± 63.0) in 6 horses. The closure measured 12-14 cm in length (13 ± 1) and consisted of mature fibrous tissue bridging the splenic capsule and the nephrosplenic ligament. No residual suture material was identified grossly in any horses. The procedure was easily performed; extracorporeal suture management to hold it taut was unnecessary since the barbs had excellent purchase in the apposed tissues, and intracorporeal knot tying was not required. CONCLUSION: The barbed knotless suture appears to be a valid alternative to facilitate laparoscopic closure of the nephrosplenic space in normal horses; however, further work is necessary to investigate its suitability in clinically affected horses.

Ex-Vivo Evaluation of a Modified Teno Fix(®) Device Repair Pattern Versus a 3-Loop Pulley for Repair of Equine Flexor Tendons.

OBJECTIVE: To compare the load to ultimate failure, load to a 2 mm gap, mode of failure, and gap at failure (mm) of the Teno Fix(®) (TF) to the 3-loop pulley (3LP) for repair of equine tendon lacerations. The use of 4TF devices versus 5TF devices on load to ultimate failure and load to a 2 mm gap was also compared. STUDY DESIGN: Ex vivo biomechanical study; unbalanced incomplete block (horse) design. SAMPLES: Cadaveric equine forelimb superficial digital flexor tendon (n = 20 paired tendons). METHODS: Ten tendon pairs were selected randomly and repaired with a 3LP and 4TF pattern, and 10 tendon pairs repaired with a 3LP and 5TF pattern. Load to ultimate failure, load to a 2 mm gap, mode of failure, and gap at failure were obtained using materials testing. RESULTS: The 3LP had a significantly greater ultimate load to failure (P < .001, respectively) and a significantly higher load to a 2 mm gap than both TF repairs (P < .001, respectively). The most frequent mode of failure was suture pull-out for the 3LP and anchor pull-out for the TF. Gap at failure was significantly larger in the 3LP than both TF repairs (P < .001). The ultimate load to failure was significantly higher for the 5TF than the 4TF (P = .004) but there was no significant difference in load to a 2 mm gap, or gap at failure between both TF repairs (P = .11, P = .15, respectively). CONCLUSIONS: Neither TF repair was stronger than the 3LP in load to ultimate failure and load to a 2 mm gap. Addition of a fifth TF device significantly increased the load to ultimate failure but did effect the load to a 2 mm gap over the 4TF.

Comparison of equine articular cartilage thickness in various joints.

PURPOSE: Thicknesses of fresh equine articular cartilage surfaces from the fetlock, carpal and stifle joints were measured employing a needle probe test. MATERIALS AND METHODS: Eighty-seven samples used in measurement were cultivated from fetlock, carpal and stifle joints of 12 deceased within 4 h of death. After approximately three minutes of exposure to air during dissection, all cartilage samples were preserved in a saline solution to keep the articular cartilage hydrated for testing. The thickness was measured on five different spots on the same sample. The thicknesses of the fetlock, carpus and stifle were compared. RESULTS: The articular cartilage of the stifle was thicker than the fetlock and carpus, while the fetlock and the carpus had similar thickness values. The average thickness of the fetlock, carpal and stifle joint are 0.86, 0.87 and 2.1 mm, respectively. They were statistically compared using the Student t-test. The differences on the articular cartilage thicknesses between the fetlock and stifle, and carpus and stifle were "very highly significant" (p < 0.001). This indicates that the articular cartilage thickness of the stifle is significantly different from that of the fetlock and carpus. Four different surfaces in the fetlock and four in the carpal joint were also compared. Significant differences between each set of the four surfaces were not observed. In the carpus, the difference in thickness between the distal radius and proximal third carpal bone articular cartilage surfaces as well as the proximal radial carpal bone and distal radial carpal bone articular cartilage surfaces were statistically significant.