Infrared spectroscopy of serum as a potential diagnostic screening approach for naturally occurring canine osteoarthritis associated with cranial cruciate ligament rupture.

OBJECTIVE: To evaluate infrared (IR) spectroscopy of serum as a screening tool to differentiate dogs affected by naturally occurring osteoarthritis (OA) associated with cranial cruciate ligament rupture (CrCLR) and controls. METHOD: 104 adult dogs with CrCLR (affected group) and 50 adult control dogs were recruited for this prospective observational study. Serum samples were collected preoperatively from CrCLR dogs and from a subset of these dogs at 4-, and 12-week post-surgical intervention to stabilize the affected stifles. Serum was collected once from control dogs. Dry films were made from serum samples, and IR absorbance spectra acquired. Data preprocessing, principal component analysis and multivariate analysis of covariance were performed to separate samples from the two groups, and to evaluate temporal differences. Weighted logistic regression with L1 regularization method was used to develop a predictive model. Model performance based on an independent test set was evaluated. RESULTS: Spectral data analysis revealed significant separation between the sera of CrCLR and control dogs (P < 0.0001), but not amongst different time points in the OA group. The sensitivity, specificity, AUC and accuracy of the test set were 84.62%, 96.15%, 93.20% and 92.31% respectively. CONCLUSIONS: These findings confirm the potential of IR-spectroscopy of serum with chemometrics methods to differentiate controls from dogs with OA associated with CrCLR. This is the first step in development of an economic, and comparatively simple IR-based screening serum test for OA. Utility of this tool as a clinical screening and diagnostic test requires further investigation and validation.

The relevance of threaded external skeletal fixation pin insertion speed in canine bone with and without predrilling.

OBJECTIVES: The effects of insertion speed in revolutions per minute (RPM) and pilot hole predrilling for placement of threaded external skeletal fixation pins on temperature and morphological damage in cortical bone were evaluated. The null hypothesis states that insertion speed and predrilling will have no significant effect on temperature and morphological damage. METHODS: Fixation pins were inserted into cadaveric canine femurs at speeds of 700 RPM and 150 RPM, with and without pre-drilling. Temperature was measured at each cortex 0.5 mm and 3.0 mm from each insertion site. Samples were examined grossly and by scanning electron microscopy for evidence of morphological damage. Data were analysed for maximum temperature, temperature increase, sites above thermal necrosis thresholds, microcracks, thread quality and gross damage. RESULTS: Predrilling had a significant effect on maximum temperature, temperature increase, sites exceeding necrosis thresholds, microcracks, thread quality and gross damage. Speed of insertion had no significant effect on any of the measured parameters following predrilling, but had a significant effect on thread quality without predrilling. CLINICAL SIGNIFICANCE: Our results fail to reject the null hypothesis concerning insertion speed, which had no significant effect on thermal damage, and minimal effect on morphological damage, which was negated by predrilling. Our results reject the null hypothesis concerning predrilling and support the practice of predrilling fixation pin insertion sites.

Stiffness of modified Type 1a linear external skeletal fixators.

Modifications of a Type 1a external skeletal fixator (ESF) frame were evaluated by alternately placing transfixation pins on opposite sides of the connecting rod (Type 1a-MOD) or by placing additional connecting rods on either of the two inside (Type 1a-INSIDE) or two outside (Type 1a-OUTSIDE) transfixation pins. The objective of this study was to evaluate the stiffness of these modifications in terms of axial compression (AC), cranial-caudal bending (CCB), and medial-lateral bending (MLB). We hypothesized that these designs would allow significant increase in unilateral frame stiffness, over Type 1a, without proportional increase in frame complexity or technical difficulty of application. All of the ESF frames were constructed using large IMEX SKtrade mark clamps, 3.2 mm threaded fixation pins, 9.5 mm carbon fibre connecting rods and Delrin rods as bone models. Nine, eight pin frames of each design were constructed, and subjected to repetitive non-destructive loading forces (AC, CCB, MLB) using a materials testing machine. Frame construct stiffness for each force (AC, CCB, MLB) was derived from load-deformation curve analysis and displayed in N/mm. Data revealed the 1a-MOD and 1a-OUTSIDE constructs had significantly increased stiffness in CCB and AC as compared to the Type 1a constructs while all of the modified constructs were significantly stiffer in MLB than the Type 1a constructs.

Priapism: a review.

Priapism is persistent penile erection in the absence of sexual stimulation. The pattern of blood flow to the penis that occurs during normal erection is altered so that sustained priapism may result in edema, increased risk of abrasion, tissue drying and necrosis of the penis. Numerous causes have been reported in animals and humans. The prognosis depends on the type of priapism and the amount of time that passes before therapeutic intervention. Surgical methods, such as aspiration and shunting procedures, have traditionally been used to treat priapism but carry a risk of postsurgical complications. Use of alpha-agonists for treatment of priapism in humans is often successful and avoids the risks of impotence and other surgical complications. Investigation of the use of alpha-agonists for treatment of priapism in animals should be considered.

Arthroscopy.

Canine arthroscopy has made significant technological and scientific advancements in the last 10 years. The history of canine arthroscopy and currently available equipment required for performing diagnostic and therapeutic arthroscopy are discussed. Basic arthroscopic techniques are described in detail. Specific approaches to the major joints and associated disease processes treatable by arthroscopic methods are reviewed. The future of canine arthroscopy is bright and specific procedures for treating the joint diseases of dogs will undoubtedly be described as the collective arthroscopic expertise of veterinary surgeons increases.

Natural history of a hamstring tendon autograft used for anterior cruciate ligament reconstruction in a sheep model.

The purpose of this study was to describe the histologic structure of the intraarticular segment of a semitendinosus tendon autograft used for anterior cruciate ligament reconstruction over the first year after surgery. We performed an anterior cruciate ligament reconstruction in a single hindlimb of 11 sheep using a doubled semitendinosus tendon autograft secured to the femur with an endoscopic button and polyester tape and to the tibia with sutures tied around a screw. The histologic structure of the intraarticular segment of the graft at 4, 8, 12, 24, and 52 weeks after surgery was compared with that of the normal semitendinosus tendon and anterior cruciate ligament. The random collagen fiber orientation progressed to a longitudinal orientation from the peripheral to the central areas of the graft over the initial 12 weeks after surgery. A uniform sinusoidal crimp pattern similar to that seen in the normal anterior cruciate ligament was identified under polarized light in nearly one-half of each graft by 24 weeks. Further maturation was noted at 52 weeks. Graft necrosis was not evident at any time period. This study showed that semitendinosus tendon autografts transform into a histologic structure similar to that of the normal anterior cruciate ligament over the initial year after surgery, as has been described for patellar tendon grafts.

Tendon-to-bone healing of a semitendinosus tendon autograft used for ACL reconstruction in a sheep model.

Anterior cruciate ligament (ACL) reconstruction was performed in a single hind limb of 30 sheep using a doubled semitendinosus tendon graft. Three additional animals were used as controls. Histologic and biomechanical analysis was performed from 4-52 weeks postoperatively. Perpendicular collagen fibers were found connecting the tendon graft to the bone tunnels at 8 weeks. These fibers were seen circumferentially at 12 weeks. By 24 weeks, the bone tunnel was well-defined, and no further changes were observed at 52 weeks. Tendon incorporation within the femoral and tibial tunnels was similar at each interval. Although the small sample size did not permit statistical testing, the reconstruction strength was similar up to 12 weeks (15%-19% of controls). This increased at 24 (28%) and 52 (40%) weeks. The stiffness primarily increased from 4-8 weeks (18%-39%) and 24-52 weeks (52%-82%). Up to 12 weeks, failures occurred by graft pull-out from the bone tunnel. All 24- and 52-week specimens ruptured through the intra-articular portion of the graft, further indicating sufficient graft incorporation within the bone tunnels.

Strength of ACL reconstructions using semitendinosus tendon grafts.

PURPOSE: Patellar tendon autografts have been considered by many as the gold standard for intraarticular reconstruction of the anterior cruciate ligament (ACL). Hamstring tendon grafts are being used increasingly, however there are few studies focusing on their mechanical properties. The objectives of the present study are to determine the strength of a semitendinosus graft at various postoperative periods. METHODS: In Part I of the study, a looped semitendinosus graft was used to reconstruct the ACL in five frozen human cadaver knees with a simulated endoscopic technique. The immediate post-operative strength was determined by loading the knees of failure using a mechanical testing system. In Part II the effects of graft maturation and incorporation were considered. A similar graft was used to reconstruct the ACL in twelve ewe sheep. Their knees were harvested and tested at four, eight, and twelve weeks postoperatively. RESULTS: The mean maximum strength and stiffness of the cadaveric reconstructions were 352 N and 8.18 N/mm, respectively. All failures occurred at the fixation sites. The average strength of the sheep reconstructions was similar at four, eight, and twelve weeks (376 N. 415 N. and 323 N. respectively). The stiffness increased from 21.1 N/mm at four weeks to 46.7 N/mm at eight weeks and then remained the same. The failures occurred primarily by tendon pull-out of the femoral tunnel at four, eight and twelve weeks. CONCLUSIONS: Graft pull-out from the femoral tunnel implies incomplete tendon incorporation during the initial three months post-operatively. Activities which place high loads on the graft should be avoided during this period. Additionally, the mechanical properties of this hamstring graft reconstruction are similar to those reported for patellar tendon grafts in other animal models.

Sciatic perineal hernia in two dogs.

A sexually intact, male Chihuahua and a spayed female poodle were presented with left perineal masses. The masses were identified as perineal hernias by rectal palpation. Surgical exploration of the perineal region in each dog revealed retroperitoneal fat protruding between the sacrotuberous ligament and the coccygeus muscle (sciatic perineal hernia). The hernias were repaired using modifications of the standard or internal obturator flap herniorrhaphies. The levator ani muscle was grossly and histologically normal in the Chihuahua and grossly normal in the poodle. No short- or long-term complications were reported in either case. The management of sciatic perineal hernia is similar to the more common caudal perineal hernia.

Metatarsophalangeal arthrodesis in three dogs.

Metatarsophalangeal (MTP) arthrodesis was done in each of three dogs with end-stage degenerative joint disease resulting from trauma and osteomyelitis (n = 2) and immune-mediated disease (n = 1). In two cases, MTP arthrodesis proved to be a useful method of eliminating pain and salvaging limb function. In one case, concurrent injuries and obesity prevented full return to function. Arthrodesis was accomplished with autogenous cancellous bone grafts and bone plates (n = 2) and with transarticular K-wires (n = 1). External coaptation was a necessary adjunct to internal fixation in all cases.

Metastatic carcinoma presenting as hind-limb lameness: diagnosis by synovial fluid cytology.

A dog presented for evaluation of left hind-limb lameness and pain associated with manipulation of the tail. Synovial metastasis of a carcinoma was diagnosed by joint fluid examination. A primary bronchiolar-alveolar carcinoma with widespread (including synovial and skeletal) metastases was diagnosed on postmortem examination. Metastasis to synovial surfaces is uncommon, but when it occurs, the metastasis-induced arthritis may be the initial presenting complaint for which medical attention is sought. Although rarely reported, cytological examination of synovial fluid may be diagnostic. This paper presents an interesting clinical case and reviews the literature concerning metastatic disease of the synovium.

Comparison of the degree of abdominal adhesion formation associated with chromic catgut and polypropylene suture materials.

OBJECTIVE: To evaluate the histologic pattern and biomechanical properties of adhesions caused by chromic catgut and polypropylene sutures, using an enteropexy model. DESIGN: Enteropexies were created in dogs, using chromic catgut and polypropylene suture. The adhesions associated with the enteropexies were examined histologically and mechanically. ANIMALS: 6 mixed-breed dogs weighing 16 to 20 kg. PROCEDURE: 72 enteropexies were created between the jejunum and abdominal wall. 36 sites were sutured with chromic catgut and 36 were sutured with polypropylene. 3 dogs were euthanatized after 1 week. The remaining dogs were euthanatized after 1 month. Samples of the enteropexy sites were obtained for histologic examination. The remaining sites were mechanically distracted until failure of the enteropexy site or adjacent tissue occurred. RESULTS: Histologic examination of the enteropexy sites did not reveal substantial differences in the degree of inflammation between the 2 suture types at 1 week or 1 month. The degree of inflammation decreased and the maturity of fibrous tissue formed at the enteropexy sites increased for all specimens over time. No statistically significant difference in breaking strength was observed between suture types at 1 week or 1 month. CONCLUSION: In dogs, the formation and strength of intentionally created abdominal adhesions are not increased by use of chromic catgut. CLINICAL RELEVANCE: Selection of chromic catgut suture for use in surgical procedures where adhesions are desired is unwarranted.

Evaluation of a one-step surgical preparation technique in dogs.

The efficacy of a 1-step surgical preparation technique for skin of dogs prior to elective ovariohysterectomy was evaluated. Dogs randomly assigned to group 1 (n = 30) had their skin prepared for surgery by use of a 2-step method, whereas the skin of dogs in group 2 (n = 30) was prepared for surgery by use of a commercially available product for a 1-step technique. Culture plates for quantitative bacterial counts were applied to the proposed incision site on dogs under general anesthesia after hair at the site was clipped and vacuumed but before antiseptic was applied. A second quantitative bacterial culture plate was applied to the proposed incision site after completion of the surgical preparation technique. Surgeries were routinely completed, and dogs were evaluated by physical examination the next day and at the time of suture removal (7 to 10 days after surgery) for complications. Postoperative complications were minor and consisted primarily of subcutaneous swelling, which resolved with time. All cultures obtained prior to skin preparation included bacteria or yeast. Sixteen cultures obtained after skin preparation (group 1, n = 11; group 2, n = 5) included bacteria or yeast. The total number of colonies of potential pathogens (Staphylococcus sp and Enterobacteriaceae) on the preparation cultures was 9,339; 4 colonies were counted on the postpreparation cultures. Potential bacterial pathogens, ie Streptococcus intermedius and gram-negative bacteria, were isolated from dogs prepared with the 2-step technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcutaneous oxygen monitoring for predicting skin viability in dogs.

Transcutaneous oxygen (PO2-TC) monitoring is commonly used in human medicine for evaluating skin viability. The application of transcutaneous monitoring for evaluating skin viability in dogs was investigated. The changes in PO2-TC values were measured from 16 avascular skin flaps created along the lateral hemithoraces of 4 dogs. Transcutaneous oxygen values were serially recorded from the vascular base and avascular apex of each flap for 12 hours after surgery. A single transcutaneous measurement was obtained from each flap base and apex 24 hours after surgery. Serial arterial blood gas analyses were obtained to compare central oxygen values with PO2-TC values. Full-thickness skin biopsy specimens were harvested from the base and apex of each flap 24 hours after surgery. The flaps were observed for 4 days and then excised for histologic examination. A subjective grading scale was used to assess histologic changes. Throughout the 12-hour period and at 24 hours, a statistically significant difference was found between the PO2-TC values for apices and bases of the flaps. The mean PO2-TC for all bases was 90.9 mm of Hg +/- 3.3 SEM, and the mean PO2-TC for all apices was 21.2 mm of Hg +/- 1.8 SEM. The mean regional perfusion index (apex PO2-TC/base PO2-TC) was 0.23 +/- 0.02. The subjective numbers assigned to the biopsy specimens were statistically evaluated by using a paired Student's t test and a Wilcoxon signed-rank test. A significant difference was found between the numbers for the collective bases and apices with both tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of skin viability in dogs, using transcutaneous carbon dioxide and sensor current monitoring.

Transcutaneous oxygen monitoring is commonly used in human beings to assess skin viability. Little attention has been directed toward the use of transcutaneous carbon dioxide (PCO2-TC) monitoring for the same purpose. The application of PCO2-TC monitoring for evaluating skin viability in dogs was investigated. The changes in PCO2-TC and local power reference (LPR) values were measured from 16 skin flaps created along the lateral hemithoraces of 4 dogs. Transcutaneous PCO2 and LPR values were serially recorded from the base and apex of each flap for 12 hours. A single measurement was obtained from each flap base and apex 24 hours after surgery. Arterial blood gas analyses were obtained to compare central PCO2 values with peripheral skin PCO2 values. The flaps were observed for 4 days and then harvested for histologic examination. Full-thickness skin biopsy specimens were obtained 24 hours after surgery and when the flaps were harvested to evaluate the viability of the apex and base of the flaps. A subjective grade was assigned to all skin biopsy specimens during histologic examination. For all measurements, a significant difference was found between the PCO2-TC values for apices and bases of the flaps. The mean PCO2-TC for all bases was 52.66 mm of Hg +/- 2.24 (SEM), and the mean PCO2-TC for all apices was 106.4 mm of Hg +/- 2.44. The regional carbon dioxide index (apex PCO2-TC/base PCO2-TC) was 2.02. A significant difference was not found between the LPR values for bases and apices.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple cardiac anomalies in a cat.

A 7-week-old domestic shorthair cat was examined because of congestive heart failure. Echocardiography and angiography were used to identify multiple cardiac anomalies. Because of the uncorrectable nature of the defects, the cat was euthanatized. Necropsy revealed persistent left vena cava, patent foramen ovale, and a right atrial/left ventricular canal. The right atrioventricular valve was replaced by a small ostium, and no chordae tendinae or papillary muscles were observed around the ostium. The pulmonary trunk originated from the right atrium. The right ventricular free wall was approximately 1 mm thick.

Identification of surgical biopsy borders by use of india ink.

Separation of surgical biopsy borders from artifactual borders created during trimming of biopsy specimens is necessary to avoid misinterpretation of histologic borders. Misinterpretation of a contaminated trimming border as a surgical border may lead to additional surgery and excessive removal of normal tissue. Likewise, a neoplasm may regrow locally or metastasize if a surgical border infiltrated with neoplastic cells is falsely assumed to be an artifactual trimming border. The use of India ink for distinguishing between surgical biopsy borders and artifactual borders was evaluated. Ten normal tissue specimens from 8 types of tissue (skin, small intestine, urinary bladder, bone, muscle, lung, large intestine, and uterus) were obtained from freshly euthanatized dogs. The specimens were painted with India ink and examined for adherence of the ink to the cut surface of the specimen. Adherence of the ink was observed in all specimens with the exception of the cut surface of the lung. Twenty-five biopsy specimens from dogs with clinical cases of disease were similarly painted with India ink and evaluated. Twenty-two were identified as neoplastic and 3 as inflammatory lesions. Wedges of tissue were obtained from the center of the biopsy specimens to purposely create borders that contained neoplastic tissue. These positive controls were painted with India ink to evaluate the effect of the ink on the histologic appearance of the neoplastic cells. Distortion or alteration of the cellular architecture was not observed in any of the normal specimens, specimens from dogs with clinical cases, or positive controls. The use of India ink for delineation of biopsy borders is a simple technique that presents few technical difficulties.(ABSTRACT TRUNCATED AT 250 WORDS)