Inflammatory pattern of the infrapatellar fat pad in dogs with canine cruciate ligament disease.

BACKGROUND: Despite the importance of inflammation during the pathogenesis of cranial cruciate ligament disease (CCLD) in dogs and despite the latest knowledge suggesting a significant role of adipose tissue in osteoarthritis, the infrapatellar fat pad (IFP) was up to now mostly disregarded in veterinary investigations. In the present study, the inflammatory activity of the IFP, the main adipose structure within the stifle joint, was thoroughly investigated to evaluate its potential impact in the pathogenesis of this common disease of our canine companions. Samples of IFP, subcutaneous adipose tissue (ScAT) of the thigh and synovial fluid in both diseased (n = 36) and healthy control (n = 23) dogs were tested for their immune cell composition but also for interleukins (IL-1ß, IL-6, IL-8, IL-10), degradative enzymes (MMP-1, MMP-3, MMP-13, TIMP-2, iNOS) and adipokines (leptin and adiponectin). Characterization of the immune cell composition was ascertained by fluorescence activated cell sorting. Gene expression and protein release of the inflammatory markers was determined by real RT-qPCR and ELISA. RESULTS: IFPs of dogs with CCLD had a significantly increased immune cell count with T cells (CD3) as the most abundant immune cells. T cells and macrophages (CD14) were significantly increased compared to healthy controls or corresponding ScAT. In addition, IFPs of dogs with CCLD demonstrated a significant increase on gene as well as protein level of multiple inflammatory indicators (IL-1ß, IL-6, MMP-1, MMP-13) compared to the other tissues. TNFα was only increased on gene expression. Adipokine analysis showed higher secretion of adiponectin and lower leptin secretion in IFP from dogs with CCLD than from controls. In the synovial fluid from dogs with CCLD concentrations of IL-1ß, MMP-1, MMP-13 as well as leptin were significantly increased compared to the synovial fluid from healthy control dogs. CONCLUSIONS: The present study indicates that the IFP is a potential contributory factor in the pathogenesis of CCLD, due to its inflammatory phenotype and the proximity within the stifle joint. To determine the extent of this possible inter-relationship, further studies need to be undertaken.

Inflammatory Processes Associated with Canine Intervertebral Disc Herniation.

Intervertebral disc herniation (IVDH) is an important pathology in humans and also in dogs. While the molecular disease mechanisms are well investigated in humans, little is known about the inflammatory mediators in naturally occurring canine IVDH. The objective of this study was to investigate whether the involved proinflammatory cytokines in human IVDH are also key cytokines in canine IVDH and thus to elucidate the suitability of the dog as a model for human trials. 59 samples from 25 dogs with surgically confirmed thoracolumbar IVDH were collected and classified in three subgroups: herniated (H), affected non-herniated (NH) disc, and adjacent non-affected (NA) disc. Discs from 11 healthy dogs acted as controls (C). Samples were analyzed for IL-1, IL-6, IL-8, and TNF-α expression (qPCR/ELISA) as well as cell infiltration and activation of the MAP kinase pathways (immunohistochemistry). Gene and protein expression of all key cytokines could be detected in IVDH affected dogs. Canine IVDH was significantly associated with a higher gene expression of IL-6 (H > C, NH > C) and TNF-α (H > C, NH > C, NA > C) and a significant down-regulation of IL-1ß (H < C). Dogs with spontaneous pain had significantly higher IL-6 mRNA compared to those with pain arising only upon palpation. An inter-donor comparison (H and HN relative to NA) revealed a significant increase of IL-6 gene expression (H > NA, NH > NA). IL-8 (H > C, NA > C) and TNF-α (NH > C) protein levels were significantly increased in diseased dogs while inversely, IL-6 protein levels were significantly higher in patients with better clinical outcome. Aside from resident IVD cells, mostly monocytes and macrophages were found in extruded material, with concomitant activation of extracellular signal-regulated kinase p38 in the majority of samples. Dogs with spontaneous IVDH might provide a useful model for human disc diseases. Although the expression of key cytokines found in human IVDH was also demonstrated in canine tissue, the inflammatory mechanisms accompanying canine IVDH diverges partially from humans, which will require further investigations in the future. In dogs, IL-6 seems to play an important pathological role and may represent a new potential therapeutic target for canine patients.

Evaluation of surface blood flow in intact and ruptured canine cruciate ligaments using laser Doppler flowmetry.

OBJECTIVE: To evaluate the usefulness of laser Doppler flowmetry (LDF) to measure surface blood flow in canine cruciate ligaments, compare measurements in different sites of intact and partially ruptured canine cranial cruciate ligaments (CrCL) and intact caudal cruciate ligaments (CaCL), and investigate any association between surface blood flow in partially ruptured CrCL and synovitis or duration of clinical signs. STUDY DESIGN: Case-controlled clinical study. ANIMALS: Sixteen dogs with partially ruptured CrCL and five dogs with intact CrCL. METHODS: Blood cell flux (BCF) readings during three measurement cycles using LDF at two sites in each ligament (mid-substance and the distal portion of the CrCL, and mid-substance and the proximal portion of the CaCL) were recorded. Synovial changes were graded grossly and histologically using the Osteoarthritis Research Society International histopathology scoring system. RESULTS: The within-run coefficients of variation (CV) for a single BCF measurement cycle were 12.2% and 12.7% in the ruptured and intact CrCL groups, respectively. The between-run CV for three measurement cycles was 20.8% and 14.8%, respectively. The intraclass correlation coefficient (ICC, absolute agreement) was 0.66 for a single measurement cycle and 0.86 for the average of three cycles. No difference in average BCF readings was found between any two sites in either group, but BCF readings in both CrCL sites were significantly higher in the ruptured CrCL group than the intact CrCL group. No associations between BCF and synovial grades or duration of lameness were identified. CONCLUSIONS: Laser Doppler flowmetry can be used to assess surface blood flow in intact and partially ruptured canine cruciate ligaments with acceptable precision. Using this method, surface blood flow appears greater in partially ruptured canine CrCL than intact CrCL. Further studies are required to determine if this is a sequela of trauma or synovitis.

Genotypes and antibiotic resistance of canine Campylobacter jejuni isolates.

Campylobacter jejuni is the most important cause of bacterial gastroenteritis in humans. It is a commensal in many wild and domestic animals, including dogs. Whereas genotypes of human and chicken C. jejuni isolates have been described in some detail, only little information on canine C. jejuni genotypes is available. To gain more information on genotypes of canine C. jejuni and their zoonotic potential, isolates from routine diagnostics of diarrheic dogs as well as isolates of a prevalence study in non-diarrheic dogs were analyzed. Prevalence of thermophilic Campylobacter among non-diarrheic dogs was 6.3% for C. jejuni, 5.9% for Campylobacter upsaliensis and 0.7% for Campylobacter coli. The C. jejuni isolates were genotyped by multi locus sequence typing (MLST) and flaB typing. Resistance to macrolides and quinolones was genetically determined in parallel. Within the 134 genotyped C. jejuni isolates 57 different sequence types (ST) were found. Five STs were previously unrecognized. The most common STs were ST-48 (11.2%), ST-45 (10.5%) and ST-21 (6.0%). Whereas no macrolide resistance was found, 28 isolates (20.9%) were resistant to quinolones. ST-45 was significantly more prevalent in diarrheic than in non-diarrheic dogs. Within the common time frame of isolation 94% of the canine isolates had a ST that was also found in human clinical isolates. In conclusion, prevalence of C. jejuni in Swiss dogs is low but there is a large genetic overlap between dog and human isolates. Given the close contact between human and dogs, the latter should not be ignored as a potential source of human campylobacteriosis.

Validation of stress magnetic resonance imaging of the canine stifle joint with and without an intact cranial cruciate ligament.

OBJECTIVE: To validate use of stress MRI for evaluation of stifle joints of dogs with an intact or deficient cranial cruciate ligament (CrCL). SAMPLE: 10 cadaveric stifle joints from 10 dogs. PROCEDURES: A custom-made limb-holding device and a pulley system linked to a paw plate were used to apply axial compression across the stifle joint and induce cranial tibial translation with the joint in various degrees of flexion. By use of sagittal proton density-weighted MRI, CrCL-intact and deficient stifle joints were evaluated under conditions of loading stress simulating the tibial compression test or the cranial drawer test. Medial and lateral femorotibial subluxation following CrCL transection measured under a simulated tibial compression test and a cranial drawer test were compared. RESULTS: By use of tibial compression test MRI, the mean ± SD cranial tibial translations in the medial and lateral compartments were 9.6 ± 3.7 mm and 10 ± 4.1 mm, respectively. By use of cranial drawer test MRI, the mean ± SD cranial tibial translations in the medial and lateral compartments were 8.3 ± 3.3 mm and 9.5 ± 3.5 mm, respectively. No significant difference in femorotibial subluxation was found between stress MRI techniques. Femorotibial subluxation elicited by use of the cranial drawer test was greater in the lateral than in the medial compartment. CONCLUSIONS AND CLINICAL RELEVANCE: Both stress techniques induced stifle joint subluxation following CrCL transection that was measurable by use of MRI, suggesting that both methods may be further evaluated for clinical use.

Effect of lateral meniscectomy and osteochondral grafting of a lateral femoral condylar defect on contact mechanics: a cadaveric study in dogs.

BACKGROUND: Osteochondral autograft transfer (OAT) aims at restoring normal articular cartilage surface geometry and articular contact mechanics. To date, no studies have evaluated the contact mechanics of the canine stifle following OAT. Additionally, there are no studies that evaluated the role of the meniscus in contact mechanics following OAT in human or canine femorotibial joints. The objective of this study was to measure the changes in femorotibial contact areas (CA), mean contact pressure (MCP) and peak contact pressure (PCP) before and after osteochondral autograft transplantation (OAT) of a simulated lateral femoral condylar cartilage defect with an intact lateral meniscus and following lateral meniscectomy. RESULTS: With an intact lateral meniscus, creation of an osteochondral defect caused a decrease in MCP and PCP by 11% and 30%, respectively, compared to the intact stifle (p < 0.01). With an intact meniscus, implanting an osteochondral graft restored MCP and PCP to 96% (p = 0.56) and 92% (p = 0.41) of the control values. Lateral meniscectomy with grafting decreased CA by 54% and increased PCP by 79% compared to the intact stifle (p < 0.01). CONCLUSIONS: OAT restored contact pressures in stifles with a simulated lateral condylar defect when the meniscus was intact. The lateral meniscus has a significant role in maintaining normal contact pressures in both stifles with a defect or following OAT. Meniscectomy should be avoided when a femoral condylar defect is present and when performing OAT.

In vitro cytoprotective effects of acetylsalicylic acid, carprofen, meloxicam, or robenacoxib against apoptosis induced by sodium nitroprusside in canine cruciate ligament cells.

OBJECTIVE: To determine whether incubation of cruciate ligament cells with acetylsalicylic acid, carprofen, meloxicam, or robenacoxib provides protection against apoptosis induced by sodium nitroprusside (SNP). SAMPLE: Explants of cranial (CCL) and caudal (CaCL) cruciate ligaments from eight 1-day-old Beagles. PROCEDURES: Primary cultures of CCL and CaCL cells were created via enzymatic dissociation of cruciate explants. Purified cell cultures were incubated for 2 hours without (controls) or with 1 of 3 concentrations of 1 of 4 NSAIDs (10, 100, or 200 µg of acetylsalicylic acid/mL; 0.1, 1, or 10 µg of carprofen/mL; 0.1, 1, or 10 µg of meloxicam/mL; or 0.1, 1, or 10 µg of robenacoxib/mL) and subsequently incubated for 18 hours with 1 of 3 concentrations of SNP in an attempt to induce mild, moderate, or severe cytotoxic effects. Cell viability and apoptosis were analyzed via a cell proliferation assay and flow cytometry, respectively. Prostaglandin E(2) concentrations were measured via an ELISA. RESULTS: Cytoprotective effects of NSAIDs were dependent on the extent of SNP-induced apoptosis and were greatest in CCL and CaCL cell cultures with moderate SNP-induced cytotoxic effects. Preincubation with an NSAID improved cell viability by 15% to 45% when CCL and CaCL cells were subsequently incubated with SNP. Carprofen (10 µg/mL) had the greatest cytoprotective effects for CCL and CaCL cells. Incubation with NSAIDs resulted in a nonsignificant decrease in PGE(2) production from SNP-damaged cells. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that carprofen, meloxicam, and robenacoxib may reduce apoptosis in cells originating from canine cruciate ligaments.

Nitric oxide induces cell death in canine cruciate ligament cells by activation of tyrosine kinase and reactive oxygen species.

BACKGROUND: There is increasing evidence suggesting that development of progressive canine cranial cruciate ligament (CCL) rupture involves a gradual degeneration of the CCL itself, initiated by a combination of factors, ranging from mechanical to biochemical. To date, knowledge is lacking to what extent cruciate disease results from abnormal biomechanics on a normal ligament or contrary how far preliminary alterations of the ligament due to biochemical factors provoke abnormal biomechanics. This study is focused on nitric oxide (NO), one of the potential biochemical factors. The NO-donor sodium nitroprusside (SNP) has been used to study NO-dependent cell death in canine cranial and caudal cruciate ligament cells and to characterize signaling mechanisms during NO-stimulation. RESULTS: Sodium nitroprusside increased apoptotic cell death dose- and time-dependently in cruciate ligamentocytes. Cells from the CCL were more susceptible to apoptosis than CaCL cells. Caspase-3 processing in response to SNP was not detected. Testing major upstream and signal transducing pathways, NO-induced cruciate ligament cell death seemed to be mediated on different levels. Specific inhibition of tyrosine kinase significantly decreased SNP-induced cell death. Mitogen activated protein kinase ERK1 and 2 are activated upon NO and provide anti-apoptotic signals whereas p38 kinase and protein kinase C are not involved. Moreover, data showed that the inhibition reactive oxygen species (ROS) significantly reduced the level of cruciate ligament cell death. CONCLUSIONS: Our data support the hypothesis that canine cruciate ligamentocytes, independently from their origin (CCL or CaCL) follow crucial signaling pathways involved in NO-induced cell death. However, the difference on susceptibility upon NO-mediated apoptosis seems to be dependent on other pathways than on these tested in the present study. In both, CCL and CaCL, the activation of the tyrosine kinase and the generation of ROS reveal important signaling pathways. In perspective, new efforts to prevent the development and progression of cruciate disease may include strategies aimed at reducing ROS.

Retrospective evaluation of postoperative nasotracheal tubes for oxygen supplementation in dogs following surgery for brachycephalic syndrome: 36 cases (2003-2007).

OBJECTIVE: To assess the utility of nasotracheal tubes in postoperative oxygen supplementation in dogs following corrective surgery for brachycephalic syndrome. DESIGN: Retrospective study 2003-2007. SETTING: University teaching hospital. ANIMALS: Thirty-six client-owned dogs that underwent corrective surgery for brachycephalic syndrome. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were reviewed for animals that underwent surgical interventions for brachycephalic syndrome including palatoplasty, ventriculectomy, and rhinoplasty. Data collected included signalment, presenting complaints, analgesic and surgical interventions, type of supplemental oxygen therapy, complications and mortality occurring during hospitalization. A nasotracheal tube (NTT) was placed in 20 dogs at the end of surgery; 16 dogs received other forms of oxygen supplementation (8) or no oxygen supplementation (8) during recovery. The total number of postoperative complications was similar in both groups (8/20 dogs with NTTs and 7/16 in those without NTTs). However, respiratory distress was observed in 5 dogs without NTTs but was not observed in any dog while an NTT was in place. One dog in each group died postoperatively. CONCLUSION: Placement of an NTT was found to be easy and may offer benefit in dogs with brachycephalic syndrome as a noninvasive means of delivering oxygen. The use of NTT may minimize severe postoperative morbidity, in particular by reducing postoperative respiratory distress.

Evaluation of respiratory parameters at presentation as clinical indicators of the respiratory localization in dogs and cats with respiratory distress.

OBJECTIVE: To describe clinical respiratory parameters in cats and dogs with respiratory distress and identify associations between respiratory signs at presentation and localization of the disease with particular evaluation between the synchrony of abdominal and chest wall movements as a clinical indicators for pleural space disease. Design - Prospective observational clinical study. SETTING: Emergency service in a university veterinary teaching hospital. ANIMALS: Cats and dogs with respiratory distress presented to the emergency service between April 2008 and July 2009. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The following parameters were systematically determined at time of admission: respiratory rate, heart rate, temperature, type of breathing, movement of the thoracic and abdominal wall during inspiration, presence of stridor, presence and type of dyspnea, and results of thoracic auscultation. Abdominal and chest wall movement was categorized as synchronous, asynchronous, or inverse. Diagnostic test results, diagnosis, and outcome were subsequently recorded. Based on the final diagnoses, animals were assigned to 1 or more of the following groups regarding the anatomical localization of the respiratory distress: upper airways, lower airways, lung parenchyma, pleural space, thoracic wall, nonrespiratory causes, and normal animals. One hundred and seventy-six animals (103 cats and 73 dogs) were evaluated. Inspiratory dyspnea was associated with upper airway disease in dogs and expiratory dyspnea with lower airway disease in cats. Respiratory noises were significantly associated and highly sensitive and specific for upper airway disease. An asynchronous or inverse breathing pattern and decreased lung auscultation results were significantly associated with pleural space disease in both dogs and cats (P<0.001). The combination is highly sensitive (99%) but not very specific (45%). Fast and shallow breathing was not associated with pleural space disease. Increased or moist pulmonary auscultation findings were associated with parenchymal lung disease. CONCLUSIONS: Cats and dogs with pleural space disease can be identified by an asynchronous or inverse breathing pattern in combination with decreased lung sounds on auscultation.

In vitro effect of different mediators of apoptosis on canine cranial and caudal cruciate ligament fibroblasts and its reversibility by pancaspase inhibitor zVAD.fmk.

Primary fibroblast cultures of canine cranial (CCL) and caudal (CaCL) cruciate ligaments were stimulated with different apoptosis inducers with or without preincubation of the pancaspase inhibitor zVAD.fmk. In contrast to CaCL fibroblasts, fibroblasts from CCL were significantly more susceptible to apoptosis inducers of the intrinsic pathway like doxorubicin, cisplatin and nitric oxide (NO)-donors and to Fas ligand (FasL), an apoptosis inducer of the death receptor pathway. Apoptotic response to staurosporine and the peroxynitrite donor GEA was similar in both ligament fibroblasts. Stimulation with dexamethasone or TNFα could not induce apoptosis in CCL and CaCL fibroblasts, in spite of present TNFR1 and TNFR2 receptors. zVAD.fmk was able to prevent apoptosis in up to 66% of CCL cells when treated with FasL, cisplatin or doxorubicin but it had no effect on NO or peroxynitrite induced apoptosis. In conclusion, differential susceptibility to apoptotic triggers like FasL or NO between cranial and caudal cruciate ligament fibroblasts in vitro may be a reflection of the different susceptibilities to degenerative rupture of the ligament. These findings indicate that a general caspase inhibition does not completely protect canine CCL cells from apoptosis.

Microfenestration using the CUSA Excel ultrasonic aspiration system in chondrodystrophic dogs with thoracolumbar disk extrusion: a descriptive cadaveric and clinical study.

OBJECTIVE: To describe an ultrasonic surgical aspirator assisted disk fenestration technique in dogs. STUDY DESIGN: Descriptive cadaveric and prospective clinical study. ANIMALS: Fresh Beagle cadavers (n=5) and 10 chondrodystrophic dogs with thoracolumbar disk extrusion. METHODS: Cadaveric study: Intervertebral disks T12-L2 were fenestrated with the CUSA Excel in 5 Beagle cadavers, and fenestration efficacy assessed by morphologic examination of the completeness of fenestration and size of annulotomy. Clinical study: the affected intervertebral disk was fenestrated in 10 chondrodystrophic dogs treated by hemilaminectomy for thoracolumbar disk disease. Efficacy of fenestration was evaluated. RESULTS: Mean time necessary to perform CUSA assisted fenestration was 8 minutes (range, 5-10 minutes) for each disk in cadavers and patients. In cadaver spines, removal of the nucleus pulposus was complete in 11/15 disks. In 4 disks, remnants of nucleus pulposus material were observed on the contralateral side. Nuclear material was normal in 9/15 disks and showed evidence of chondroid degeneration on histopathologic examination in the 6 disks. Median annulotomy size was 3 mm. Clinically, no signs of early recurrence were observed and all dogs recovered uneventfully. CONCLUSIONS: CUSA assisted fenestration is a safe and efficient method of fenestration for removal of most of the nucleus pulposus through a limited annulotomy.

Incidence of spinal compressive lesions in chondrodystrophic dogs with abnormal recovery after hemilaminectomy for treatment of thoracolumbar disc disease: a prospective magnetic resonance imaging study.

OBJECTIVE: To investigate causes of the lack of clinical improvement after thoracolumbar disc surgery. STUDY DESIGN: Case-control magnetic resonance imaging (MRI) study. ANIMALS: Chondrodystrophic dogs with acute thoracolumbar disc disease treated by hemilaminectomy: 10 that had no short-term clinical improvement and 12 with "normal" clinical improvement. METHODS: Dogs that had surgery for treatment of intervertebral disc extrusion (2003-2008) where thoracolumbar disc disease was confirmed by MRI were evaluated to identify dogs that had lack of clinical improvement after surgery. Ten dogs with delayed recovery or clinical deterioration were reexamined with MRI and compared with 12 dogs with normal recovery and MRI reexamination after 6 weeks (control group). RESULTS: Of 173 dogs, 10 (5.8%) had clinical deterioration within 1-10 days after surgery. In 8 dogs, residual spinal cord compression was identified on MRI. Bleeding was present in 1 dog. In 3 dogs, the cause was an incorrect approach and insufficient disc material removal. In 3 dogs, recurrence occurred at the surgical site. In 1 dog, the centrally located extruded material was shifted to the contralateral side during surgery. These 8 dogs had repeat surgery and recovery was uneventful. In 2 dogs, deterioration could not be associated with a compressive disc lesion. Hemorrhagic myelomalacia was confirmed by pathologic examination in 1 dog. The other dog recovered after 6 months of conservative management. CONCLUSION: Delayed postsurgical recovery or deterioration is commonly associated with newly developed and/or remaining compressive disc lesion. CLINICAL RELEVANCE: We recommend early MRI reexamination to assess the postsurgical spinal canal and cord, and to plan further therapeutic measures in chondrodystrophic dogs with delayed recovery after decompressive hemilaminectomy for thoracolumbar disc disease.

Right ventricular rupture after lateral thoracotomy for removal of rib-associated telangiectatic osteosarcoma in a dog.

OBJECTIVE: To describe a case of a focal right ventricular rupture following removal of a rib-associated telangiectatic osteosarcoma (TOS) in a dog. CASE SUMMARY: A 2-year-old spayed female mixed-breed dog, weighing 20 kg, was presented in compensated hypovolemic shock due to active bleeding into the thoracic cavity. The dog was stabilized with appropriate fluid administration. Subsequent computed tomographic examination revealed a large mineralized mass originating from the body of a rib and displacing the heart. Two days after surgical removal of this mass, focal right ventricular rupture occurred and the dog died. The mass was later identified as a TOS. NEW OR UNIQUE INFORMATION PROVIDED: Although hemothorax secondary to TOS has been described previously, this report describes for the first time, spontaneous focal right ventricular rupture as a rare complication of thoracotomy and rib resection for the removal of a rib-associated, intrathoracic TOS.

Laser-Doppler measurements of spinal cord blood flow changes during hemilaminectomy in chondrodystrophic dogs with disk extrusion.

OBJECTIVES: (1) To assess spinal cord blood flow (SCBF) during surgical treatment of disk extrusion in dogs and (2) to investigate associations between SCBF, clinical signs, presurgical MRI images, and 24-hour surgical outcome. STUDY DESIGN: Cohort study. ANIMALS: Chondrodystrophic dogs with thoracolumbar disk extrusion (n=12). METHODS: Diagnosis was based on clinical signs and MRI findings, and confirmed at surgery. Regional SCBF was measured intraoperatively by laser-Doppler flowmetry before, immediately after surgical spinal cord decompression, and after 15 minutes of lavaging the lesion. Care was taken to ensure a standardized surgical procedure to minimize factors that could influence measurement readings. RESULTS: A significant increase in intraoperative SCBF was found in all dogs (Wilcoxon's signed-rank test; P=.05) immediately after spinal cord decompression and after 15 minutes. Changes in SCBF were not associated with duration of clinical signs; initial or 24-hour neurologic status; or degree of spinal cord compression assessed by MRI. CONCLUSION: SCBF increases immediately after spinal cord decompression in dogs with disk herniation; however, increased SCBF was not associated with a diminished 24-hour neurologic status. CLINICAL RELEVANCE: An increase in SCBF does not appear to be either associated with the degree of spinal cord compression or of a magnitude sufficient to outweigh the benefit of surgical decompression by resulting in clinically relevant changes in 24-hour outcome.

Influence of intervertebral disc fenestration at the herniation site in association with hemilaminectomy on recurrence in chondrodystrophic dogs with thoracolumbar disc disease: a prospective MRI study.

OBJECTIVE: To describe the influence of fenestration at the disc herniation site on recurrence in thoracolumbar disc disease of chondrodystrophoid dogs. STUDY DESIGN: Prospective clinical study. ANIMALS: Chondrodystrophic dogs (n=19). METHODS: Dogs were divided into 2 groups: group 1 (9 dogs) had thoracolumbar disc extrusion (Hansen type I) treated by hemilaminectomy and concomitant fenestration of the affected intervertebral disc and group 2 (10 dogs) had hemilaminectomy without fenestration. All dogs had 3 magnetic resonance imaging (MRI) examinations: preoperatively, immediately postoperatively to assess removal of herniated disc material, and again 6 weeks after surgery. RESULTS: There were 13 male and 6 female dogs; mean age, 7.1 years. Thoracolumbar disc herniation was confirmed with MRI. Immediate post surgical MRI revealed that the herniated disc removal was complete in all but 1 dog and that fenestration did not lead to complete removal of nucleus pulposus within the intervertebral disc space. On the 3rd MRI examination, none of the group 1 dogs had further disc material herniation at the fenestrated site. Six of the 10 group 2 dogs had a recurrence of herniation leading to clinical signs in 3 dogs (pain in 2 dogs, paresis in 1 dog). CONCLUSION: In thoracolumbar disc herniation, fenestration of the affected intervertebral disc space prevents further extrusion of disc material. CLINICAL RELEVANCE: Fenestration reduces the risk of early recurrence of disc herniation and associated postoperative complications.

Apoptosis of ligamentous cells of the cranial cruciate ligament from stable stifle joints of dogs with partial cranial cruciate ligament rupture.

OBJECTIVE: To describe the presence and amount of apoptotic ligamentous cells in different areas of partially ruptured canine cranial cruciate ligaments (prCCLs) and to compare these findings with apoptosis of ligamentous cells in totally ruptured cranial cruciate ligaments (trCCLs). ANIMALS: 20 dogs with prCCLs and 14 dogs with trCCLs. PROCEDURES: Dogs with prCCLs or trCCLs were admitted to the veterinary hospital for stifle joint treatment. Biopsy specimens of the intact area of prCCLs (group A) and the ruptured area of prCCLs (group B) as well as specimens from trCCLs (group C) were harvested during arthroscopy. Caspase-3 and poly (ADP-ribose) polymerase (PARP) detection were used to detect apoptotic ligamentous cells by immunohistochemistry. RESULTS: No difference was found in the degree of synovitis or osteophytosis between prCCLs and trCCLs. No difference was found in degenerative changes in ligaments between groups A and B. A substantial amount of apoptotic cells could be found in > 90% of all stained slides. A correlation (r(s) = 0.71) was found between the number of caspase-3-and PARP-positive cells. No significant difference was found in the amount of apoptotic cells among the 3 groups. No significant correlation could be detected between the degree of synovitis and apoptotic cells or osteophyte production and apoptotic cells. CONCLUSIONS AND CLINICAL RELEVANCE: The lack of difference between the 3 groups indicates that apoptosis could be a factor in the internal disease process leading to CCL rupture and is not primarily a consequence of the acute rupture of the ligament.

Accuracy of the withdrawal reflex for localization of the site of cervical disk herniation in dogs: 35 cases (2004-2007).

OBJECTIVE: To evaluate the accuracy of neurologic examination versus magnetic resonance imaging (MRI) in localization of cervical disk herniation and evaluate the usefulness of withdrawal reflex testing in dogs. DESIGN: Retrospective case series. ANIMALS: 35 client-owned dogs with a single-level cervical disk herniation as determined via MRI. PROCEDURES: 1 of 2 board-certified neurologists performed a complete neurologic examination in each dog. Clinical signs of a cervical lesion included evidence of neck pain and tetraparesis. The withdrawal reflex was used for neuroanatomic localization (C1-C5 or C6-T2). Agreement between results of neurologic and MRI examinations was determined. RESULTS: Agreement between neurologic and MRI diagnoses was 65.8%. In 11 dogs in which the lesion was clinically localized to the C6-T2 segment on the basis of a decreased withdrawal reflex in the forelimbs, MRI revealed an isolated C1-C5 disk lesion. In 1 dog, in which the lesion was suspected to be at the C1-C5 level, MRI revealed a C6-T2 lesion. Cranial cervical lesions were significantly associated with an incorrect neurologic diagnosis regarding site of the lesion. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the withdrawal reflex in dogs with cervical disk herniation is not reliable for determining the affected site and that a decreased withdrawal reflex does not always indicate a lesion from C6 to T2.

Thoracolumbar dorsolateral laminectomy with osteotomy of the spinous process in fourteen dogs.

OBJECTIVE: To describe outcome after an alternative unilateral approach to the thoracolumbar spine for dorsal laminectomy. STUDY DESIGN: Retrospective clinical study. ANIMALS: Dogs (n=14) with thoracolumbar spinal cord compression. METHODS: Thoracolumbar spinal cord compression was lateral (6 dogs), dorsal (4), and dorsolateral (4) caused by subarachnoid (7) and synovial cysts (2) and intradural-extramedullary neoplasia (5). All dogs were treated by dorsal laminectomy with osteotomy of the spinous process using a unilateral paramedian approach. The contralateral paraspinal muscles were not stripped from the spinous process and the osteoligamentous complexes were preserved. Retraction of the spinous process and muscles to the contralateral side resulted in complete visualization of the dorsal vertebral arch thereby allowing dorsal laminectomy to be performed. RESULTS: No technique complications occurred. Approximately 75% exposure of the spinal cord (dorsal and lateral compartments) was achieved providing adequate visualization and treatment of the lesions. Transient deterioration of neurologic state occurred in 5 dogs because of extensive spinal cord manipulation. At long-term follow-up, 6 dogs were normal, 6 had clinical improvement, and 2 were unchanged. CONCLUSION: Dorsal laminectomy after osteotomy and retraction of the spinous process may be considered in canine patients with dorsal, dorsolateral, or lateral compression to facilitate adequate decompression of the spinal cord. CLINICAL SIGNIFICANCE: This surgical technique offers an alternative approach to the thoracolumbar spine and spinal cord by a modified dorsal laminectomy that preserves the paraspinal muscle integrity on the contralateral side.

Iatrogenic sciatic nerve injury in eighteen dogs and nine cats (1997-2006).

OBJECTIVE: To report clinical features associated with iatrogenic peripheral nerve injury in dogs and cats admitted (1997-2006) to a referral teaching hospital. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=18), 9 cats. METHODS: Patients had acute signs of monoparesis attributable to sciatic nerve dysfunction that developed after treatment. Neurologic examination and electrodiagnostic testing were performed. Surgical therapy was used for nerve entrapment and delayed reconstructive surgery used in other cases. RESULTS: Of 27 nerve injuries, 25 resulted from surgery (18 with treatment of pelvic injuries). Iliosacral luxation repair resulted in tibial (4 cats) and peroneal (3 dogs) nerve dysfunction. Other causes were intramedullary pinning of femoral fractures (3), other orthopedic surgery (cemented hip prosthesis [2] and tibial plateau-leveling osteotomy [1]), and perineal herniorrhaphy [1]. Nerve injury occurred after intramuscular injection (1 cat, 1 dog). Immediate surgical treatment was removal of intramedullary nails, extruded cement, or entrapping suture. Delayed nerve transplantation was performed in 2 dogs. Within 1 year, 13 patients recovered completely, clinical improvement occurred in 7, and there was no improvement in 7. Five of the 7 dogs that did not recover had acetabular or ilium fracture. CONCLUSION: Iatrogenic sciatic nerve injury occurred most commonly during treatment of pelvic orthopedic diseases and had a poor prognosis. Clinical variation in sciatic nerve dysfunction in dogs and cats can be explained by species anatomic differences. CLINICAL RELEVANCE: Iatrogenic sciatic nerve injury leads to severely debilitating locomotor dysfunction with an uncertain prognosis for full-functional recovery.