bluuebunny/crossref_metadata_2025 huggingface dataset:
Repair and Function of Synovium After Arthroscopic Synovectomy of the Dorsal Compartment of the Equine Antebrachiocarpal Joint
Authors: THEORET CHRISTINE L. , BARBER SPENCER M. , MOYANA TERENCE , TOWNSEND HUGH G.G. , ARCHER JOY F.
Published: February 2008

The reparative ability of equine synovium was determined by gross, histological, and ultrastructural examination. The functional potential of the synovium was estimated by examination of synovial cell organelles with transmission electron microscopy. Results from rested and exercised horses were compared to determine the effect of exercise on synovial healing. The response of the synovectomized joint to exercise was evaluated with a standardized lameness examination and by gross, histological, and histochemical observations of the articular cartilage. A 7‐mm diameter motorized synovial resector was used to perform a subtotal synovectomy in 1 antebrachiocarpal joint of each of 8 horses; the contralateral joint served as a control. After 2 months rest, four randomly selected horses were rigorously exercised for the remainder of the study; the other four horses continued paddock rest. Lameness examinations and synovial fluid analyses were conducted at 0, 2, 30, 60, and 120 days. Synovium and articular cartilage from all horses were examined at necropsy at 120 days. None of the horses were lame during the study, and a transient synovitis occurred in the synovectomized joints. The hyaluronan concentration of treated joints decreased at 2 days but returned to normal by 60 days. Synovial fluid composition, including hyaluronan concentration, was unchanged by exercise. Significant cartilage damage was not observed in any of the joints. At 120 days, the healing synovium was devoid of villi and its subintima was fibrotic, however transmission electron microscopy confirmed that an intimal layer was present within the repair tissue. The cells within the repair tissue appeared actively engaged in both synthesis and phagocytosis. Exercise did not modify any of these findings. The results of this study suggest that 120 days after subtotal synovectomy, the joint environment was maintained and the resected synovium had evidence of restoration and increased metabolic potential. Synovectomized joints withstood exercise but synovial repair was not accelerated by exercise.
Open Peritoneal Drainage in Horses With Experimentally Induced Peritonitis
Authors: CHASE JAMES P. , BEARD WARREN L. , BERTONE ALICIA L. , GOLTZ KAREN
Published: February 2008

Peritonitis was induced in 12 horses by median celiotomy and 1 hour of small intestinal ischemia. Six horses had primary closure of the incision, whereas six horses had a plastic mesh sutured to the ventral abdominal wall leaving the abdomen open for ventral drainage. The mesh was removed after 5 days and the abdominal wall was closed by apposition of the linea alba and subcutaneous tissues and approximation of the skin edges. Peritoneal fluid was collected and analyzed for nucleated cell count and total protein concentration on days 0 and 5. Serum biochemical profiles, serum electrolyte concentrations, and complete blood counts were performed on days 0, 1, 2, 5, 6, 10, and 14. Body weight, rectal temperature, and physical examination findings were recorded daily for 30 days, then horses were euthanatized and the abdominal cavity was examined for the presence of adhesions. Histological examination was performed to assess the inflammatory response of the healing body wall; inflammation scores were significantly lower in horses that had primary closure of the incision. The mesh was well tolerated by all horses and allowed egress of peritoneal fluid for 5 days. Adhesions were present in four control horses and in two horses that had open peritoneal drainage. All horses that had open drainage developed incisional infections after mesh removal. Abdominal wall herniation did not occur in any of the horses. The mild peritonitis induced in this study was insufficient to establish the efficacy of open peritoneal drainage for an established peritonitis in horses; however, the results of this study indicate that open peritoneal drainage is feasible in horses.
Metacarpophalangeal Joint Synovial Pad Fibrotic Proliferation in 63 Horses
Authors: DABAREINER ROBIN M. , WHITE NATHANIEL A. , SULLINS KENNETH E.
Published: February 2008

Medical records, radiographs, and sonograms of 63 horses with metacarpophalangeal joint synovial pad proliferation were examined retrospectively. All horses had lameness, joint effusion, or both signs associated with one or both metacarpophalangeal joints. Bony remodeling and concavity of the distodorsal aspect of the third metacarpal bone (Mc3) just proximal to the metacarpal condyles was identified by radiography in 71 joints (93%); 24 joints (32%) had radiographic evidence of a chip fracture located at the proximal dorsal aspect of the proximal phalanx. Fifty‐four joints (71%) were examined by ultrasound. The mean ± SD sagittal thickness of the synovial pad was 11.3 ± 2.8 mm. Seventy‐nine percent of the horses had single joint involvement with equal distribution between the right and left forelimbs. Sixty‐eight joints in 55 horses were treated by arthroscopic surgery. Sixty joints (88%) had debridement of chondral or osteochondral fragmentation from the dorsal surface of Mc3 beneath the synovial pad and 30 joints (44%) had a bone chip fracture removed from the medial or lateral proximal dorsal eminence of the proximal phalanx. Complete or partial excision of both medial and lateral synovial pads was completed in 42 joints. Only the medial synovial pad was excised or trimmed in 21 joints, and 5 joints had only the lateral pad removed. Eight joints in eight horses were treated by stall rest, administration of intra‐articular medication and systemic nonsteroidal anti‐inflammatory drugs. Follow‐up information was obtained for 50 horses treated surgically and for eight horses treated medically. Forty‐three (86%) that had surgery returned to racing; 34 (68%) raced at an equivalent or better level than before surgery. Three (38%) of the medically treated horses returned to racing; only one horse raced better than the preinjury level. Horses that returned to racing at a similar or equal level of performance were significantly younger in age than horses returning at a lower level or not racing (P≤.05). Overall, horses with synovial pad proliferation treated by arthroscopic surgery had a good prognosis for return to racing at a level equal or better than before injury.
Postcaval Thrombosis and Delayed Shunt Migration After Pleuro‐Peritoneal Venous Shunting for Concurrent Chylothorax and Chylous Ascites in a Dog
Authors: PETERSON STEVEN L.
Published: February 2008

Simultaneous chylothorax and chylous ascites related to intestinal lymphangiectasia was diagnosed in a 4‐year‐old spayed female dog. Palliative pleural and peritoneal drainage was accomplished by placement of fenestrated silastic sheeting into surgically created diaphragmatic defects, and implantation of a pleuro‐peritoneal venous shunt. The immediate postoperative period was complicated by acute renal failure secondary to postcaval thrombosis originating at the site of placement of the efferent pump catheter and extending to the level of the renal veins. Rapid resolution of this complication was accomplished with systemic anticoagulation. Clinical signs related to fluid accumulation resolved for 10 weeks after which acute decompensation occurred and the dog was euthanatized. Postmortem examination showed that reaccumulation of fluid was associated with migration of the efferent limb of the shunt from the caudal vena cava.
Comparisons of Sevoflurane, Isoflurane, and Halothane Anesthesia in Spontaneously Breathing Cats
Authors: HIKASA YOSHIAKI , KAWANABE HISAHIRO , TAKASE KATSUAKI , OGASAWARA SHIGEO
Published: February 2008

The clinical effects of sevoflurane, isoflurane, and halothane anesthesia with or without nitrous oxide, were compared in healthy, premedicated cats breathing spontaneously during 90 minutes of anesthesia. The effect of nitrous oxide in accelerating the induction of and recovery from anesthesia was more evident for halothane than for sevoflurane or isoflurane. The cats recovered more rapidly from sevoflurane‐oxygen than from either halothane‐ or isoflurane‐oxygen. Heart rates did not significantly change during anesthesia with any of the anesthetics. Arterial blood pressures during sevoflurane‐oxygen anesthesia were somewhat higher than those with either isoflurane‐ or halothane‐oxygen. There were no significant differences in arterial blood pressures among sevoflurane, isoflurane, and halothane anesthesia when combined with nitrous oxide. The respiration rate during sevoflurane‐oxygen was similar to that during halothane‐oxygen. There were no significant differences in respiration rate among sevoflurane, isoflurane, and halothane anesthesia when combined with nitrous oxide. The degree of hypercapnia and acidosis during sevoflurane anesthesia was similar to that observed during isoflurane anesthesia and less than during halothane anesthesia. The three anesthetic regimens, with or without nitrous oxide, induced a similar degree of hyperglycemia and hemodilution during anesthesia. Serum biochemical examination did not reveal any hepatic or renal injuries after each anesthesia.
Transportal Approach for Attenuating Intrahepatic Portosystemic Shunts in Dogs
Authors: HUNT G.B. , BELLENGER C.R. , BVSc M.R.B. PEARSON
Published: February 2008

A novel surgical approach, using portal venotomy during total hepatic vascular occlusion, was used to locate and attenuate congenital intrahepatic portosystemic shunts in nine dogs. Shunt location was consistent with a persistent ductus venosus in only two dogs. In the remaining seven dogs the shunts were window‐like orifices arising from either the left (two dogs) or right portal vein branch (five dogs) and communicating with the ipsilateral hepatic vein or caudal vena cava. The transportal approach using total hepatic vascular occlusion consistently provided good access to the portosystemic shunts, including those with window‐like communications. A 7 to 16 minute period of total vascular occlusion was well‐tolerated hemodynamically, with few intraoperative complications. Intrahepatic shunts were successfully attenuated in eight dogs, while one dog with portal atresia was euthanatized. The postoperative course was complicated by high protein pulmonary edema (one dog), an encapsulated biliary pseudocyst (one dog) and uncontrollable hemorrhage caused by an uncharacterized coagulopathy (one dog). Three dogs required a second operation to further attenuate their shunts. The clinical condition of all seven surviving dogs was improved after surgery.
In Vitro Biomechanical and Histological Assessment of Pilot Hole Diameter for Positive‐Profile External Skeletal Fixation Pins in Canine Tibiae
Authors: CLARY ERIK M. , ROE SIMON C.
Published: February 2008

This study was conducted to evaluate the effect of pilot hole (PH) diameter (0, 1.5, 2.0, 2.7, 3.1, 3.3, 3.5, and 3.7 mm) on the biomechanical and microstructural performance of positive‐profile threaded external skeletal fixation pins (3.18 mm inner diameter, 3.97 mm outer diameter) using cadaveric canine tibiae. Eight pins per pilot hole diameter (four pins per bone) were used to assess differences in end‐insertional torque and pin pull‐out strength. Histological evaluation of eight bicortical pin tracts per pilot hole diameter was accomplished using computer‐interfaced videomicroscopy on specimens processed using a bulk‐staining technique. Compared with no predrill, use of 2.7 mm PH increased end‐insertional torque and pull‐out strength by 25% and 13.5%, respectively. No significant differences were observed in biomechanical variables for the PH diameter range of 2.0 to 3.1 mm. Compared with no predrill, use of a 3.1 mm PH increased thread area by 18%. Microfracturing around the threads decreased as PH diameter increased. Damage to the interface at the entry and exit sites of both near and far cortices also decreased as PH diameter increased. It was concluded that predrilling a PH whose diameter approximates, but does not exceed the inner diameter of the positive profile pin will not only improve initial pin stability compared with no predrilling, but it will also reduce microstructural damage that may lead to excessive bone resorption and premature pin loosening.
Myoperitoneal Microvascular Free Flaps in Dogs: An Anatomical Study and a Clinical Case Report
Authors: DEGNER DANIEL A. , LANZ OTTO I. , WALSHAW RICHARD
Published: February 2008

The purpose of the anatomical study was to identify potential myoperitoneal microvascular free flaps, in dogs, that are based on a single artery and vein. The angiosomes of the right deep circumflex iliac artery and left phrenicoabdominal (cranial abdominal) artery were evaluated in six medium‐sized canine cadavers. The right deep circumflex iliac artery and left phrenicoabdominal (cranial abdominal) artery were injected with a mixture of barium and latex (equal parts). The entire right and left transversus abdominis muscles were dissected from the abdominal wall and radiographed. The angiograms of the deep circumflex iliac artery showed poor arborization of the vessels within the transversus abdominis muscle in all six cadavers. The angiograms of the phrenicoabdominal (cranial abdominal) artery showed consistent filling of the vascular bed of the cranial half of the transversus abdominis muscle flap in all six dogs. The vascular pedicle lengths and the diameter of the arteries and veins of both the deep circumflex iliac and phrenicoabdominal (cranial abdominal) myoperitoneal free flaps were found to be acceptable for microvascular anastomosis. The deep circumflex iliac flap was unacceptable because of inadequate vascular perfusion. The cranial abdominal artery had a consistent, large branch that supplied the cranial half of the transversus abdominis muscle, thereby making a myoperitoneal flap supplied by this vessel a potentially useful free flap. An 8‐year‐old male, neutered, mixed‐breed dog was evaluated for possible repair of a large defect of the hard palate. Previous operations, using local tissue flaps, had been unsuccessful. A myoperitoneal free flap, based on the right cranial abdominal artery, and consisting of the cranial portion of the transversus abdominis muscle, was used successfully to reconstruct the hard palate. Migrating epithelium from the edges of the wound covered the myoperitoneal flap by 10 weeks after surgery. Therefore, the cranial abdominal myoperitoneal free flap can be considered for reconstruction of intra‐oral defects that cannot be repaired using conventional local flap techniques.
Efficacy of an Epidural Combination of Morphine and Detomidine in Alleviating Experimentally Induced Hindlimb Lameness in Horses
Authors: SYSEL ANNETTE M. , PLEASANT R. SCOTT , JACOBSON JOHN D. , MOLL H. DAVID , MODRANSKY PAULA D. , WARNICK LORIN D. , SPONENBERG D. PHILLIP , EYRE PETER
Published: February 2008

Amphotericin B‐induced synovitis of the left tarsocrural joint was used to create a grade 3 of 4 lameness in 11 horses. Caudal epidural catheters were placed and advanced to the lumbosacral region. Baseline heart and respiratory rates were recorded and horses were videotaped at a walk and trot. Morphine sulphate (0.2 mg/kg) and detomidine hydrochloride (30 μg/kg) were administered to treated horses (n = 8) through the epidural catheter; an equivalent volume of physiologic saline solution was administered to control horses (n = 3) through the catheter. At hourly intervals after epidural injection for a total of 6 hours, heart and respiratory rates were recorded, and horses were videotaped walking and trotting. At the end of the observation period, video recordings were scrambled onto a master videotape. Lamenesses were scored by three investigators unaware of group assignment or treatment time. Lameness scores, heart rates, and respiratory rates were compared between groups using repeated measures analysis of variance. There was a significant decrease in lameness score after treatment with epidural morphine and detomidine (P=.0003); average lameness scores of treated horses were less than grade 1 at each hourly observation for 6 hours after drug administration. Early in the observation period, heart rates significantly increased in control horses and decreased in treated horses (P=.03). A similar trend occurred for respiratory rates (P=.07). Results of this study demonstrate that epidural administration of a combination of morphine and detomidine is capable of providing profound hindlimb analgesia in horses.
The Effects of Wound Lavage Solutions on Canine Fibroblasts: An In Vitro Study
Authors: BUFFA EUGENE A. , LUBBE ANTON M. , VERSTRAETE FRANK J. M. , SWAIM STEVEN F.
Published: February 2008

Objective—The purpose of this study was to determine the effects of phosphate‐buffered saline (PBS), sterile tap water, normal saline, and Ringer's lactate on wound healing in an in vitro model.

Study Design—The effects of PBS, sterile tap water, normal saline, and Ringer's lactate on a primary line of canine embryonic fibroblasts were determined.

Animals or Sample Population—A primary line of canine embryonic fibroblasts.

Methods—The effects of the various lavage solutions were determined by (1) vital staining of the treated cells with a 0.5% trypan blue solution, (2) evaluation of the amount of lactate dehydrogenase released by the treated cells, and (3) cytopathologic evaluation of hematoxylin and eosin‐stained monolayers of treated canine fibroblasts. The cells were exposed to the lavage treatments for the following time intervals: 0.5 minute, 1 minute, 2.5 minutes, 5 minutes, and 10 minutes. PBS was used as the control.

Results—Sterile tap water significantly damaged canine fibroblasts at all time intervals (P= .05). This was attributed to the alkaline pH, hypotonicity, and presence of numerous cytotoxic trace elements in the tap water used. Cytotoxic effects were noted in fibroblasts after 10 minutes' exposure to normal saline; this may be because of the acidic pH of normal saline and lack of a buffering system. Ringer's lactate did not induce any significant fibroblast injury.

Conclusions—PBS and Ringer's lactate do not induce any significant fibroblast injury, whereas normal saline and sterile tap water cause mild and severe cytotoxic effects in vitro.

Clinical Relevance—Further clinical investigation is indicated to establish whether Ringer's lactate is the wound lavage solution of choice compared with normal saline. Sterile tap water may cause considerable fibroblast injury.
Paralumbar Fossa Laparoscopic Ovariectomy in Horses With Use of Endoloop Ligatures
Authors: BOURÉ LUDOVIC , MARCOUX MARCEL , LAVERTY SHEILA
Published: February 2008

Objective—The purposes of this study were to develop a technique of paralumbar fossa laparoscopic ovariectomy using Endoloop ligatures and to avoid a laparotomy incision for ovary removal by using a 33–mm diameter muscle spreader trocar‐cannula unit.

Animals or Sample Population—Seven mares.

Methods—Bilateral laparoscopic ovariectomy was performed under general anesthesia in two horses and under neuroleptanalgesia and local anesthesia in five standing mares. Ovaries were approached from the ipsilateral paralumbar fossa through two portal sites located in the paralumbar fossa and a third between the 17th and 18th ribs. Insufflation of the abdominal cavity was achieved using an automatic carbon dioxide insufflator. Two Endoloop ligatures were placed on the mesovarium. The cannula, located in the center of the paralumbar fossa, was removed, and a 33‐mm diameter trocar‐cannula unit, with a cone‐shaped muscle spreader extremity, was inserted through the same portal. The mesovarium was transected between the ovary and the ligatures. The ovaries were removed from the abdomen through the 33‐mm diameter cannula. The abdominal wall was closed in a routine manner.

Results—No major complications occurred during or after surgery.

Conclusion—Paralumbar fossa laparoscopic ovariectomy in mares using Endoloop ligatures and the 33‐mm diameter trocar‐cannula unit was an effective technique for ovariectomy of normal ovaries in this study.

Clinical Relevance—Endoloop ligatures provide a viable alternative for laparoscopic ligation of ovarian pedicles in mares.
Evaluation of the Palmaz Stent in the Trachea and Mainstem Bronchi of Normal Dogs
Authors: RADLINSKY MARYANN G. , FOSSUM THERESA W. , WALKER MICHAEL A. , AUFDEMORTE THOMAS B. , THOMPSON JAMES A.
Published: February 2008

Objective— This study evaluates the efficacy of the Palmaz balloon expandable intraluminal stent in the trachea and mainstem bronchi of normal dogs.

Study Design— Effects of the stent were evaluated by physical examination, thoracic radiography, respiratory tract fluoroscopy and endoscopy, tracheal diameter measurement, postmortem examination, and airway histomorphometry.

Animals or Sample Population— Ten normal beagle dogs.

Methods— Stent size was estimated from thoracic radiographs in awake dogs. Group I dogs (n = 4) had two stents placed: one in the thoracic trachea (TT) plus a randomly chosen mainstem bronchus (MB). Group II dogs (n = 3) had stents placed in the MB (one stent), TT (one stent), and mid‐ or proximal cervical trachea (CT) (one or two stents). Three dogs were used as sham‐operated controls (group III). Temperature, pulse, respiration, and cough were measured twice daily. Dogs were evaluated at 21 and 49 to 56 days after stent placement, euthanatized, and tissues were collected for histomorphometric analysis of stent integration and epithelial pathology. Results— Mean tracheal diameters of awake (10.5 ±1.7 mm) and anesthetized dogs before stent implantation (13.9 ± 2.0 mm) were significantly different (P <.01). Complications associated with stent placement included acute pulmonary edema (n = 2), stent migration (n = 7), stent collapse (n = 4 CT, 2 TT, and 1 MB), and positive tracheal culture (n = 10). Group II dogs coughed more at rest, exercise, and with tracheal palpation than dogs in other groups (P <.01). Group I dogs coughed more at rest than group III dogs (P <.01). Stent integration ranged from 0 to 91.3%. Squamous metaplasia and epithelial ulceration associated with stents ranged from 0 to 57.5% and 0 to 32.7%, respectively.

Conclusions— Determination of stent size should be based on measurements taken on anesthetized dogs because use of inappropriately sized stents may promote stent migration, squamous metaplasia, and/or ulceration. Epithelialization over stent struts may occur if the stent is closely associated with tracheal epithelium.

Clinical Relevance— Palmaz stents do not appear to be appropriate for placement in the CT of dogs; however, with technical modifications, application in the TT and MB may be feasible.
Evaluation of Skin Bacterial Flora Before and After Aseptic Preparation of Clipped and Nonclipped Arthrocentesis Sites in Horses
Authors: HAGUE BRENT A. , HONNAS CLIFFORD M. , SIMPSON R. BRUCE , PELOSO JOHN G.
Published: February 2008

Objective—This study evaluates skin bacterial flora before and after aseptic preparation of clipped and nonclipped arthrocentesis sites in horses.

Study Design—The hair over one midcarpal joint and one distal interphalangeal joint on each horse was clipped. The contralateral joint served as the nonclipped comparison.

Animals or Sample Population—Twelve adult horses.

Methods—A prescrub sample for microbial culture was taken from the dorsal surface of all four joints for each horse. Each site was aseptically prepared with povidone iodine and 70% alcohol, followed by postscrub sampling for microbial culture. Colony forming units (CFUs) were determined for each sample, 24 hours after inoculation of blood agar plates.

Results—There was no significant difference (P >.05) in number of postscrub CFUs between clipped and nonclipped skin over the midcarpal or distal interphalangeal joints. Percent bacterial reduction (mean ± SD%) after aseptic preparation differed significantly (P=.02) between clipped (99.8 ±.003%) and nonclipped (96.2 ±.05%) skin at the midcarpal joint, but not at the distal interphalangeal joint (clipped, 98.5 ±.03% and nonclipped, 97.8 ± 0.21%). There was a significant difference (P=.009) in number of prescrub CFUs obtained from clipped and nonclipped skin for the midcarpal joint. There was no significant difference in number of prescrub CFUs between clipped and nonclipped skin at the distal interphalangeal joint. Bacteria isolated from both clipped and nonclipped skin sampled postscrub includedBacillussp, nonhemolyticStaphylococcussp, andMicrococcussp.

Conclusions—The presence of hair over the midcarpal and distal interphalangeal joints does not appear to inhibit the ability of antiseptics to effectively reduce bacterial flora to an acceptable level for arthrocentesis.

Clinical Relevance—Aseptic preparation of the skin over the midcarpal and distal interphalangeal joints can be accomplished without hair removal in horses.
Intra‐articular Anesthesia of the Distal Interphalangeal Joint Alleviates Lameness Associated With the Navicular Bursa in Horses
Authors: PLEASANT R. SCOTT , MOLL H. DAVID , LEY WILLIAM B. , LESSARD PIERRE , WARNICK LORIN D.
Published: February 2008

Objective— To determine if intra‐articular anesthesia of the distal interphalangeal joint could alleviate lameness associated with the navicular bursa in horses.

Study Design— Experimental investigation.

Animals— Six clinically normal horses.

Methods— Lameness was induced in each horse by injecting either the left or right front navicular bursa with 5 mg of amphotericin‐B. Forty‐eight hours later each horse was videotaped walking and trotting before, and 5, 30, and 60 minutes after injecting the distal interphalangeal joint of the treated limb with 5 mL of 2% mepivacaine hydrochloride. All video recordings were then rerecorded onto master tapes in a random sequence. Four clinicians, unaware of the animal identity related to observation time or limb treated, independently viewed these tapes and graded the lamenesses.

Results— There was a significant reduction in lameness 5 and 30 minutes after anesthetic was injected into the distal interphalangeal joint. Lameness scores 60 minutes after anesthetic administration were not significantly different than baseline values. Gross pathological examination confirmed marked inflammation of the treated navicular bursae and normal appearance of the distal interphalangeal joints.

Conclusions— Intra‐articular anesthesia of the distal interphalangeal joint can alleviate lameness associated with the navicular bursa.

Clinical Relevance— Intra‐articular anesthesia of the distal interphalangeal joint is not specific only for lameness originating in the distal interphalangeal joint.
Comparison of Three Methods of Ulnar Fixation in Horses
Authors: HANSON PETER D. , HARTWIG HEATHER , MARKEL MARK D.
Published: February 2008

Objective‐This study compares the mechanical properties of three methods of equine ulnar fixation: dynamic compression plating, pins and wires tension band, and a prototype grip system.

Study Design‐The mechanical properties of dynamic compression plating, pins and wires tension band, and a prototype grip system repair of equine ulnar fractures were evaluated in a cadaveric osteotomy model.

Animals or Sample Population‐Fifteen pairs of the radius and ulna from equine cadavers.

Methods‐The three repair techniques were evaluated to mimic the pull of the triceps brachii muscle in single cycle to failure and in cyclic fatigue loading. Single cycle results were evaluated as the axial and angular displacement. Cyclic fatigue results were evaluated as the number of cycles to failure.

Results‐Dynamic compression plate fixation and pins and wires tension band had significantly less axial displacement of the proximal fragment than the grip system (P<.05). No significant difference in angular rotation of the proximal fragment was present between the three techniques. Dynamic compression plating had significantly greater fatigue resistance than the grip system (P<.05). Cyclic failure was characterized by screw loosening or breakage and wire breakage.

Conclusions‐Dynamic compression plates were better than the other techniques at maintaining compression of a transverse ulnar osteotomy at the level of the anconeal process just proximal to the trochlear notch.

Clinical Relevance‐Knowledge of fixation technique mechanical properties is essential for surgeons to select the proper method of fracture repair.
The Effects of Ischemia and Reperfusion on Mucosal Respiratory Function, Adenosine Triphosphate, Electrolyte, and Water Content in the Ascending Colon of Ponies
Authors: McANULTY J.F. , STONE W.C. , DVM B.J. DARIEN
Published: February 2008

Objective‐The purpose of this study was to examine the effects of ischemia and reperfusion on the biochemical integrity of equine colonic mucosa to assess the relative roles of ischemic‐ and reperfusion‐induced damage.

Study Design‐Two hours of no‐flow ischemia experimentally induced by 720° counterclockwise ascending colon volvulus followed by 2 hours reperfusion after derotation.

Animals‐Ten ponies.

Methods‐Ascending colon biopsies were obtained every hour for measurement of mucosal adenosine triphosphate (ATP), water, sodium, and potassium content. Additional samples were homogenized for assay of mitochondrial respiratory function.

Results‐ATP content diminished 92% after ischemia and recovered to only 44% of control levels (P<.001 versus controls) after 2 hours reperfusion. Reperfusion increased mucosal water and decreased sodium and potassium content for the duration of the experiment. Both NADH‐ (pyruvate) and FADH‐linked (succinate) respiration decreased after ischemia and did not recover during reperfusion indicating electron transport chain dysfunction.

Conclusions‐Two hours ischemia induced severe metabolic dysfunction in equine colon mucosa which persisted throughout reperfusion. Unequivocal evidence of injury specific to reperfusion was not observed in this study suggesting that much of the damage observed during reperfusion may be a continuation of injury induced during the ischemic period and not specific to reperfusion per se.

Clinical Relevance‐This study suggests that greater efforts to metabolically support ischemically injured mucosa may be an important aspect of obtaining improved survival of horses affected by ascending colon volvulus (ACV).
Clinical and Radiographic Evaluation of Intertrochanteric Osteotomy in Dogs: A Retrospective Study of 18 Dogs
Authors: EVERS PETRA , KRAMEK BETTY A. , WALLACE LARRY J. , JOHNSTON GARY R. , KING VICKIE
Published: February 2008

Objective‐To determine whether intertrochanteric osteotomy (ITO) can prevent the progression of degenerative joint disease (DJD) in dysplastic hip joints.

Study Design‐The results of ITO were assessed retrospectively by using owner questionnaires, physical examination, and radiographic evaluation.

Animals‐Eighteen client‐owned dogs (29 coxofemoral joints were evaluated).

Methods‐Lameness was scored according to a grading system. A scoring system was also developed to assess radiographically evident osteoarthritis on a ventrodorsal projection of the coxofemoral joints in extension.

Results‐Twenty‐nine ITO were performed in 18 dogs with varying degrees of hip dysplasia. The dogs were lame on 19 of 29 rear limbs on physical examination before surgery. In 22 of the 29 hip joints, palpation caused signs of pain. The median age at the first and second surgical procedure was 14.5 months and 18 months, respectively. Follow‐up evaluation was performed on average at 9.77 (FU I), 22.52 (FU II), and 47.50 months (FU in) after surgery. Based on the owners' evaluation, there was a tendency toward improvement after surgery. The results of the physical examination at the preoperative examination and at the three follow‐up examinations did not differ significantly. The follow‐up radiographic scores showed significantly worse DJD than the preoperative scores.

Conclusions‐ITO does not prevent progression of DJD in the dysplastic hip.

Clinical Relevance‐Knowledge of the long‐term effects of ITO is essential for surgeons trying to achieve improvement in dogs with hip dysplasia.
Deep Hypothermic Low Flow Cardiopulmonary Bypass in Small Dogs
Authors: LEW LINDA J. , EGGER CHRISTINE M. , THOMSON DOROTHY J. , ROSIN MARK W. , PHARR JOHN W.
Published: February 2008

Objective— To evaluate the feasibility of and morbidity and mortality associated with cardiopulmonary bypass (CPB) using deep hypothermia and low flow perfusion in adult dogs weighing less than 10 kg.

Study Design— Prospective, descriptive study.

Animals— Two groups of three dogs underwent CPB. Group 1 dogs underwent deep hypothermia (15 to 18°C), 45 minutes of low perfusion flow (20 mL/kg/min) and 1 hour of aortic cross clamp time. In group 2, ultrafiltration of perfusate before discontinuation of bypass was added to the standard treatment. Complete blood counts, serum biochemistry, urine output, ejection fraction, and cardiac output were monitored before and for 7 days after surgery.

Results— All dogs were successfully weaned from bypass. Four of six dogs survived, three without major complications. One dog developed and recovered from septic pleuritis. Two dogs died or were eudianatized after surgery because of respiratory or gastrointestinal complications. Minor complications included anemia, hypoproteinemia, and electrolyte disturbances. Transfusion requirements and edema formation were reduced by ultrafiltration.

Conclusions— The observations in this study support the feasibility of low flow hypothermic CPB. Meticulous tissue handling, precise equipment, ultrafiltration, and aggressive postoperative potassium supplementation are recommended for smaller patients.

Clinical Relevance— Increased sensitivity to adverse sequelae of CPB may be associated with small patient size. Further evaluation is necessary before routine clinical application of low flow hypothermic CPB in tMs patient population.
Dissipation of Heat During Polymerization of Acrylics Used for External Skeletal Fixator Connecting Bars
Authors: MARTINEZ STEVEN A. , ARNOCZKY STEVEN P. , FLO GRETCHEN L. , BRINKER WADE O.
Published: February 2008

Objective— To determine the amount of heat conducted by transfixation intramedullary pins (IP) and Kirschner wires (KW) during polymerization of acrylics used for external skeletal fixator (ESF) connecting bars.

Study Design— Thermal conduction was measured using thermistors applied to IP and KW surfaces during the polymerization phase of acrylics.

Methods— Type II ESF were created from IP or KW placed into wooden dowels and plastic tubing used to create connecting bars filled with one of two types of acrylic (Acrylic Pin External Fixation System or Technovit, Jorgensen Laboratories, Loveland, CO). Thermistors were positioned on the acrylic column surface and on IP or KW surfaces 5 or 10 mm from the acrylic column. Five ESF test groups were created. The maximum temperature (Tmax) of the acrylic column (Tmax‐A), IP (Tmax‐IP), KW (Tmax‐KW), and duration that Tmax‐IP or Tmax‐KW remained greater than or equal to 55°C were calculated.

Results— All IP and KW thermistors placed 5 mm from acrylic columns reached mean temperatures greater than 50°C and had peak temperature ranges greater than 55°C compared with all IP and KW thermistors placed 10 mm from the acrylic columns in all groups. Thermistors placed 5 mm from the acrylic column in two groups maintained temperatures greater than 55°C for greater than or equal to 0.5 minutes.

Conclusions— Acrylic columns positioned 5 mm from a thermistor on a IP or KW had the potential to reach or exceed temperatures that have been reported to cause thermal necrosis of tissues.

Clinical Relevance— Acrylic Pin External Fixation System or Technovit acrylic connecting bars used in ESF designs have the potential to cause thermal injury to soft and bony tissue by thermal conduction along transfixation pins or wires.
Transsphenoidal Hypophysectomy in Beagle Dogs: Evaluation of a Microsurgical Technique
Authors: MEIJ BJÖRN P. , VOORHOUT GEORGE , INGH TED S.G.A.M. VAN DEN , HAZEWINKEL HERMAN A.W. , VERLAAT JOHANNA W. VAN ‘T
Published: February 2008

Objective— Assessment of a microsurgical technique for transsphenoidal hypophysectomy in dogs.

Study Design— Prospective study using physical examination, pituitary function testing, computed tomography (CT), and histological examination at autopsy.

Animals or Sample Population— Eight laboratory beagle dogs.

Methods— Pituitary function was assessed before and at 10 weeks after hypophysectomy by combined administration of four releasing hormones (anterior pituitary), administration of haloperidol (pars intermedia), and infusion of hypertonic saline (posterior pituitary).

Results— CT imaging enabled accurate preoperative localization of the pituitary. Appropriate positioning and surgical technique facilitated exposure of the pituitary and its extraction without hemorrhage. Postoperative recovery was generally uncomplicated. None of die eight dogs had somatotropic, gonadotropic, lactotropic, melanotropic, or posterior pituitary responses to stimulation at 10 weeks after hypophysectomy. Four dogs (ACTH nonresponders) also had no cortico‐tropic response and four (ACTH responders) had small but significant responses in the combined anterior pituitary function test. Adrenocortical atrophy was more pronounced in the ACTH nonresponders man in the responders. No residual pituitary tissue was found along the ventral hypothalamic diencephalon but nests of pituitary cells were found embedded in fibrous tissue in the sella turcica.

Conclusions— The surgical technique proved to be safe and effective. Microscopic nests of pituitary cells in the sella turcica may be responsible for residual corticotropic response to hypophysiotropic stimulation after hypophysectomy.

Clinical Relevance— The surgical technique may be used in the treatment of dogs with pituitary‐dependent hyperadrenocorticism. The corticotropic response is the most sensitive criterion in assessing completeness of hypophysectomy in dogs.
A Modified Teniotomy Technique for Facilitated Removal of Descending Colon Enteroliths in Horses
Authors: HASSEL DIANA M. , YARBROUGH TOM B.
Published: February 2008

Objective—To describe a method for facilitating movement of enteroliths obstructing the proximal portion of the descending colon.

Study Design—Prospective report. Sample Population—15 horses.

Methods—A seromuscular incision through the antimesenteric taenia of the proximal portion of the descending colon was used to facilitate movement of enteroliths.

Results—Teniotomy allowed proximal descending colon enteroliths located within the abdomen or close to the abdominal wall to be advanced 4 to 15 cm in an aboral direction so that they could be exteriorized for safe removal.

Conclusions and Clinical Relevance

Teniotomy is a feasible method for mobilizing enteroliths in the proximal descending colon in locations that cannot otherwise be exteriorized.
Osteochondral Dowel Transplantation for Repair of Focal Defects in the Knee: An Outcome Study Using an Ovine Model
Authors: HURTIG MARK B , NOVAK KELLI , McPHERSON ROGER , McFADDEN SEAN , McGANN LOCKSLEY E. , MULDREW KEN , SCHACHAR NORMAN S.
Published: February 2008

Objective—A model system was developed to objectively assess the quality of articular cartilage after surgical reconstruction of focal defects in the medial femoral condyle using osteochondral dowel grafts.

Study Design—The surgical technique was developed and customized to reproducibly minimize surgical trauma and graft instability in order to improve the survival of the transplanted cartilage and the long‐term integrity of the joint surfaces.

Animals or Sample Population—24 adult female Suffolk‐Romanoff crossbred sheep.

Methods—Biomechanical creep testing, paravital staining for chondrocyte viability, histological analysis, and gross morphological analysis were performed at 3, 6, and 12 months postoperatively to compare fresh autografted osteochondral dowels with allografts that had been subject to a freezing protocol known to kill chondrocytes. The latter was used to investigate the time course of cartilage degeneration after injury. These two groups were also compared with normal unoperated control tissue.

Results—Biomechanical behavior, chondrocyte survival, and cartilage histology differed significantly between fresh grafts and those that had been frozen.

Conclusions—Indentation testing and paravital staining were able to identify degenerative changes earlier than other methods of assessment. The technique developed here reproducibly and reliably transplanted osteochondral dowel grafts while minimizing the confounding effects of surgical trauma and graft instability.

Clinical Relevance—The technique provides both a promising surgical technique for the repair of focal defects of the medial femoral condyle and a sensitive model for the future study of cryopreservation strategies for articular cartilage.
In Vivo Evaluation of Intramedullary Interlocking Nail Fixation of Transverse Femoral Osteotomies in Foals
Authors: McCLURE S.R. , ACVS Dipiomate , WATKINS J.P. , ACVS Diplomate , ASHMAN R.B.
Published: February 2008

Objective—To evaluate an intramedullary interlocking nail for stabilization of transverse femoral osteotomies in foals.

Study Design—A transverse osteotomy and restabilization with an intramedullary interlocking nail was performed on the right femur in three foals and the left femur in three foals. Animals—Six foals weighing 149 to 207 kg.

Methods—The femur was destabilized with a transverse middiaphyseal osteotomy and repaired with a 0.5‐in (12.7 mm) interlocking nail. The implanted femurs were radiographed monthly until completion of the study 6 months after surgery. At the completion of the study, all foals were observed for evidence of lameness, gluteal thickness was determined by ultrasonographic measurement, and a necropsy was performed.

Results—Healing was satisfactory in all foals. Five of the six had osseous bridging of the osteotomy apparent radiographically by 3 to 4 months. The sixth foal had postoperative infection but was healed radiographically in 5 months. There was a mean decrease in gluteal muscle thickness of 6.6 mm (P= .04) in the operated limb of the five foals that healed without complication. Two foals were lame at the completion of the project; one foal with varus deformities of the contralateral limb was mechanically lame, and another was grade 2/5 lame on the operated limb. On necropsy, there was circumferential enlargement of the diaphysis of all operated limbs with the majority of the callus at the cranial and medial aspects of the cortex. All nails were solid within the medullary cavity.

Conclusions—The intramedullary interlocking nail provided adequate stabilization for repair of the transverse osteotomy.

Clinical Relevance—Further investigation is warranted before use for stabilization of spontaneously occurring fracture configurations.
Determination of Proximal Femoral Epiphyseal Depth for Repair of Physeal Fractures in Immature Dogs
Authors: LORINSON DRAGAN , MILLIS DARRYL L. , BRIGHT RONALD M.
Published: February 2008

Objective—To determine the depth that implants may be safely placed for repair of proximal femoral physeal fractures.

Study Design—Relationships were determined between the depth of the proximal femoral epiphysis (PFE) and the contralateral PFE, and the PFE and pubic bone width.

Animals or Sample Population—20 immature dog cadavers.

Methods—Actual PFE depths were determined at the center of the physeal surface and at four other eccentric points. The contralateral intact PFE depth and the width of the cranial aspect of the pubic bone were measured from radiographs.

Results—Mean ratios of actual central PFE depth to radiographically measured (1) contralateral PFE depth and (2) pubic bone width were 1.04:1 and 1.09:1, and ratios of actual eccentric PFE depths were 0.89:1 and 0.93:1. Body weight was not useful in estimating depth of the PFE.

Conclusions—For the central epiphysis, pins may safely be placed a distance equal to 75% to 80% of the contralateral intact PFE depth or pubic bone width, measured from a ventrodorsal radiograph, with minimal risk of penetration through the articular surface. Pins placed eccentrically may be safely driven a depth equal to 65% of the radiographically measured contralateral intact PFE depth or pubic bone width.

Clinical Relevance—Estimating the safe depth of implant placement into the PFE avoids penetration of the articular surface.
Radiographic, Densitometric, and Biomechanical Effects of Recombinant Canine Somatotropin in an Unstable Ostectomy Gap Model of Bone Healing in Dogs
Authors: MILLIS DARRYL L. , WTLKENS BRENT E. , DANIEL GREGORY B. , HUBNER KARL , MATHEWS ARCHIE , BUONOMO FRANCES C. , PATELL KANAIYALA R. , WEIGEL JOSEPH P.
Published: February 2008

Objective—To determine the effect of recombinant canine somatotropin (STH) on radiographic, densitometric, and biomechanical aspects of bone healing using an unstable ostectomy gap model.

Study Design—After an ostectomy of the midshaft radius, bone healing was evaluated over an 8–week period in control dogs (n = 4) and dogs receiving recombinant canine STH (n = 4).

Animals or Sample Population—Eight sexually intact female Beagle dogs, 4 to 5 years old. Methods—Bone healing was evaluated by qualitative and quantitative evaluation of serial radiographs every 2 weeks. Terminal dual‐energy x‐ray absorptiometry and three‐point bending biomechanical testing were also performed.

Results—Dogs receiving STH had more advanced radiographic healing of ostectomy sites. Bone area, bone mineral content, and bone density were two to five times greater at the ostectomy sites of treated dogs. Ultimate load at failure and stiffness were three and five times greater in dogs receiving STH.

Conclusions—Using the ostectomy gap model, recombinant canine STH enhanced the radiographic, densitometric, and biomechanical aspects of bone healing in dogs. Clinical Relevance—Dogs at risk for delayed healing of fractures may benefit from treatment with recombinant canine STH.