Investigation of neutering status and age of neutering in female Dachshunds with thoracolumbar intervertebral disc extrusion.

OBJECTIVES: To evaluate neutering status and age of neutering in female Dachshunds with thoracolumbar intervertebral disc extrusion. We hypothesised that neutered Dachshunds presented with intervertebral disc extrusion at an earlier age, with a higher grade of neurological deficits and with more extensive extrusion of disc material compared with intact females. MATERIALS AND METHODS: Retrospective multi-centre study of client-owned female Dachshunds with surgically confirmed thoracolumbar intervertebral disc extrusion. Dogs were classified as early, late or not neutered (intact). Age, body condition score, duration of clinical signs before presentation, modified Frankel score at presentation, length of extruded disc material, maximum spinal cord compression and whether dogs presented for a subsequent intervertebral disc extrusion were recorded. RESULTS: One hundred and fifty-four dogs were included: 36 early neutered, 69 late neutered and 49 intact. No significant difference was found between early neutered, late neutered and entire female Dachshunds in any of the variables studied. CLINICAL SIGNIFICANCE: In this cohort of female dogs, neuter status and age of neutering were not found to affect age at onset nor severity of thoracolumbar intervertebral disc extrusion.

Postoperative outcome of ambulatory dogs with intervertebral disc extrusion causing incontinence and/or tail dysfunction: 18 cases (2010-2020).

OBJECTIVES: To assess the recovery of urinary continence, faecal continence and tail function in ambulatory dogs with caudal lumbar intervertebral disc extrusion and to explore clinical factors that may be associated with recovery. MATERIALS AND METHODS: Medical records from January 2010 to December 2020 were searched to identify ambulatory dogs undergoing surgical treatment for a caudal lumbar intervertebral disc extrusion causing urinary incontinence, faecal incontinence and/or tail dysfunction. Signalment, history, presenting clinical signs, neurological examination findings, diagnostic test results, treatment and outcome were recorded for all dogs. RESULTS: Eighteen dogs with caudal lumbar intervertebral disc extrusion causing tail dysfunction, urinary and/or faecal incontinence were included. Urinary continence was recovered in 12 (86%) of 14 affected dogs, faecal continence recovered in nine (90%) of 10 affected dogs and tail function recovered in 13 (87%) of 15 affected dogs. Loss of tail nociception was recorded in three dogs on presentation; two made a full recovery and one showed mild persistent tail paresis. CLINICAL SIGNIFICANCE: The prognosis for functional recovery of urinary continence, faecal continence and tail function in ambulatory dogs with caudal lumbar intervertebral disc extrusion following surgical treatment is good. Larger studies are needed to identify prognostic factors associated with failure of recovery.

Late onset recurrence of clinical signs after surgery for intervertebral disc extrusion in French bulldogs.

OBJECTIVES: To identify the prevalence of recurrence of clinical signs after initial successful decompressive surgery for intervertebral disc extrusion in French bulldogs. MATERIALS AND METHODS: A medical record search was performed to identify French bulldogs that experienced an initial successful outcome after surgery for thoracolumbar or cervical intervertebral disc extrusion. Collected information included signalment, neurological examination findings, intervertebral disc extrusion location, presence of vertebral malformations, kyphosis, type and extent of surgery. Decompressive surgery was not followed by extensive prophylactic fenestrations. Follow-up information was retrieved from medical records and telephone interviews with referring veterinary surgeons. RESULTS: Eighty-four French bulldogs with thoracolumbar (n=55) or cervical (n=29) intervertebral disc extrusion were included. Forty-three (51%) dogs that had decompressive surgery for thoracolumbar (n=29) or cervical (n=14) intervertebral disc extrusion suffered recurrence of signs. The median time between decompressive surgery and recurrence of clinical signs was 9 months and 21 days. Of the 29 dogs suffering recurrence of clinical signs following surgery for thoracolumbar intervertebral disc extrusion, 24 returned for recurrence of clinical signs localised to the thoracolumbar segments, while five returned for recurrence of signs localised to the cervical region. Of the 14 dogs who suffered recurrence of signs following surgery for cervical intervertebral disc extrusion, nine returned for signs localised to the cervical region, while five returned for clinical signs localised to the thoracolumbar region. CLINICAL SIGNIFICANCE: This study suggests a high rate of late onset recurrence of clinical signs after decompressive surgery for intervertebral disc extrusion in French bulldogs. This information can aid in the management of owner expectations.

Is there a link between bacteriuria and a reversible encephalopathy in dogs and cats?

Bacteriuria has been associated with abnormal neurological status in humans, especially geriatric patients. In this report, we review 11 cases (seven dogs and four cats) that suggest an association between bacteriuria and abnormal neurological status in veterinary medicine. These cases showed diffuse forebrain signs with or without brainstem signs, but primary brain disease was excluded by MRI and cerebrospinal fluid analysis. Bacteriological culture of urine was positive in each animal and neurological deficits improved or resolved with initiation of antibiosis ± fluid therapy and levetiracetam. While further studies are needed to definitively confirm or refute the link between bacteriuria and a reversible encephalopathy, urine bacteriological culture should be considered in veterinary patients presented with acute onset forebrain neuro-anatomical localisation, even in the absence of clinical signs of lower urinary tract inflammation.

Clinicopathologic Features and Magnetic Resonance Imaging Findings in 24 Cats With Histopathologically Confirmed Neurologic Feline Infectious Peritonitis.

BACKGROUND: Feline infectious peritonitis (FIP) is the most common infectious central nervous system (CNS) disease in the cat and is invariably fatal. Improved means of antemortem diagnosis is required to facilitate clinical decision making. Information regarding the magnetic resonance imaging (MRI) findings of neurologic FIP currently is limited, resulting in the need for better descriptions to optimize its use as a diagnostic tool. OBJECTIVE: To describe the clinicopathologic features and MRI findings in cases of confirmed neurologic FIP. ANIMALS: Twenty-four client-owned cats with histopathologic confirmation of neurologic FIP. METHODS: Archived records from 5 institutions were retrospectively reviewed to identify cases with confirmed neurologic FIP that had undergone antemortem MRI of the CNS. Signalment, clinicopathologic, MRI, and histopathologic findings were evaluated. RESULTS: Three distinct clinical syndromes were identified: T3-L3 myelopathy (3), central vestibular syndrome (7), and multifocal CNS disease (14). Magnetic resonance imaging abnormalities were detected in all cases, including meningeal contrast enhancement (22), ependymal contrast enhancement (20), ventriculomegaly (20), syringomyelia (17), and foramen magnum herniation (14). Cerebrospinal fluid was analysed in 11 cases; all demonstrated a marked increase in total protein concentration and total nucleated cell count. All 24 cats were euthanized with a median survival time of 14 days (range, 2-115) from onset of clinical signs. Histopathologic analysis identified perivascular pyogranulomatous infiltrates, lymphoplasmacytic infiltrates, or both affecting the leptomeninges (16), choroid plexuses (16), and periventricular parenchyma (13). CONCLUSIONS AND CLINICAL IMPORTANCE: Magnetic resonance imaging is a sensitive means of detecting neurologic FIP, particularly in combination with a compatible signalment, clinical presentation, and CSF analysis.

Clinical presentation and outcome of dogs treated medically or surgically for thoracolumbar intervertebral disc protrusion.

To date, few studies have investigated the clinical characteristics of thoracolumbar intervertebral disc protrusion (IVDP). The aim of this retrospective study was to evaluate the presentation and outcome of dogs receiving medical or surgical treatment for thoracolumbar IVDP. Eighty-four dogs were included, with a median age of 9.4 years. German shepherd dogs and Staffordshire bull terriers were the most common breeds. Significantly more surgically treated dogs (n=53) had neurological deficits and were non-ambulatory, compared with medically treated (n=31). Outcome data were available for 27 of 31 medically managed dogs; 11 initially improved, 7 remained stable and 9 deteriorated. Of 18 dogs that initially improved or stabilised, 10 (55.6 per cent) demonstrated recurrence of clinical signs within 12 months of diagnosis. Outcome data were available for 45 of 50 surgically treated dogs that survived to hospital discharge; 34 improved, 9 remained stable and 2 deteriorated following surgery. Of 43 dogs that improved or stabilised with surgical treatment, 11 (25.6 per cent) demonstrated recurrence of clinical signs within 12 months of surgery. Overall, significantly more surgically treated dogs (71.1 per cent) had a successful outcome, consisting of sustained clinical improvement of more than 12 months duration, compared with medically treated dogs (29.6 per cent).

Oligodendrocyte progenitors: adult stem cells of the central nervous system?

Oligodendrocyte progenitors (OPs) are a major proliferating cell population within the adult CNS. In response to myelin loss or increasing demand, OPs have the capacity to differentiate into mature, myelinating oligodendrocytes. The name 'oligodendrocyte progenitor' suggests restriction to the oligodendrocyte cell lineage. However, with growing evidence of the lineage plasticity of OPs both in vitro and in vivo, we discuss whether they have potential beyond that expected of dedicated progenitor cells, and hence may justify categorization as adult stem cells.

Remyelination: the true regeneration of the central nervous system.

The myelin sheath, generated by oligodendrocytes in the central nervous system (CNS), is crucial to neuronal function, enabling rapid propagation of nerve impulses and providing trophic support to the axon. Remyelination is the default response to myelin damage. Oligodendrocyte precursor cells, distributed throughout both the grey and white matter of the CNS, are activated in response to myelin injury, undergoing proliferation, migration to the site of damage and differentiation into mature myelinating oligodendrocytes. The end result is complete reconstruction of the area of myelin loss. However, this remarkable regenerative capacity of the CNS becomes less efficient with age and can show clinically significant failure in diseases such as multiple sclerosis. Without the myelin sheath, neuronal function and survival is compromised, leading to axonal degeneration and progressive deterioration in neurological function. Therapies to enhance remyelination could offer a means to prevent the neurological decline of chronic demyelinating disease. In order to develop such therapies, a detailed understanding of the process of remyelination, the major cellular players involved and the mechanisms of remyelination failure is needed. As the intricacies of remyelination continue to be unravelled, effective remyelination therapies are ever closer to becoming a reality.

Spinal hemiepiphysiodesis correlates with physeal histomorphometric gradients.

Compression of a growth plate is known to correlate with changes to growth plate structure. The purpose of this study was to determine if the height of the physeal hypertrophic zones and chondrocyte size were directly related to the distance from a spine implant. The implant was designed with the goal of slowing spine growth asymmetrically. For stapled vertebrae, hypertrophic zone height, cell height and cell width were decreased across the coronal plane of the growth plate, with the lowest values under the staple, 8 weeks postoperatively.

Bilateral intra-annular spinal compressive stresses in vivo.

The purpose of this pilot study was to determine if compressive stresses in the annulus of the intervertebral disc vary with activity in a quadruped and are affected by treatment with an implant. Pilot in vivo tests were conducted on skeletally immature domestic pigs (approved by IACUC). One pair of sensors was implanted within the annulus of T10-11, and the second pair at T8-9. A staple was them implanted across the right side of T8-9. Wires were routed subcutaneously and exited at the dorsal cervical region. Sensor signals were acquired before and after staple implantation, post-operatively during normal activities, and biweekly under anesthesia. After 8 weeks, spines were harvested and imaged. Early results from 2 sensors during walking and sitting, post-op day 5, clearly showed cyclic stresses during gait. Stresses were attenuated at the stapled vertebra compared to the unstapled vertebra.

Growth plate forces in the adolescent human knee: a radiographic and mechanical study of epiphyseal staples.

The purpose of this study was to quantify the forces produced by the growth plates of the adolescent human proximal tibia and distal femur. The postoperative deformations of staples used to treat genu valgum were correlated with similar staple deformations produced by mechanical testing. Staple deformation was measured in sequential radiographs of 35 knees in 20 patients. Mechanical tests were performed on new staples to determine the force necessary to bend the staples to the observed displacements. Based on deformation at final examination, the static equivalent loads exerted at the joint centerline by the growth plates of the proximal tibia and distal femur were 0.5 kN per physis. The estimated corresponding stress was 1 MPa. These results indicated that successful lower limb hemiepiphysiodesis suppressed a longitudinally directed, centrally applied compressive force on the order of body weight.

Endoscopic pelvic osteotomy for the treatment of hip dysplasia.

Adolescent and adult hip dysplasia can be surgically treated by rotating the acetabulum into a better weight-supporting position; however, open pelvic osteotomies are among the most invasive of all pediatric orthopaedic procedures. Endoscopic pelvic osteotomy offers the theoretical advantages of magnified visualization of the bone cuts, minimized surgical dissection, and rapid postoperative recovery. The technique of endoscopically assisted triple innominate osteotomy requires the combination of endoscopic skills and facility with more standard surgical approaches.

The effect of surgical timing on the perioperative complications of treatment of supracondylar humeral fractures in children.

BACKGROUND: The purpose of this study was to evaluate the perioperative complication rates associated with early surgical treatment (eight hours or less following injury) and delayed surgical treatment (more than eight hours following injury) of displaced supracondylar humeral fractures in children. METHODS: Fifty-two patients had early surgical treatment and 146 patients had delayed surgical treatment of a displaced supracondylar humeral fracture. The perioperative complication rates of the two groups were compared with the use of bivariate and multivariate statistical methods. RESULTS: There was no significant difference between the two groups with respect to the need for conversion to formal open reduction and internal fixation (p = 0.56), pin-track infection (p = 0.12), or iatrogenic nerve injury (p = 0.72). No compartment syndromes occurred in either group. Power analysis revealed that our study had an 86% power to detect a 20% difference between the two groups if one existed. CONCLUSIONS: We were unable to identify any significant difference, with regard to perioperative complication rates, between early and delayed treatment of displaced supracondylar humeral fractures. Within the parameters outlined in our study, we think that the timing of surgical intervention can be either early or delayed as deemed appropriate by the surgeon.

Two cases of osteochondroma recurrence after surgical resection.

Osteochondromas are the most common bone tumor found in children. A review of 114 resected osteochondromas over a 10-year period revealed recurrence in 2 cases. The overall recurrence rate of these lesions is less than 2% and was found to be 1.8% in this review.

Tension pneumothorax as a complication of video-assisted thorascopic surgery for anterior correction of idiopathic scoliosis in an adolescent female.

STUDY DESIGN: This case report illustrates the occurrence of intraoperative tension pneumothorax, a previously unreported complication occurring during anterior instrumentation for correction of scoliosis by video-assisted surgery. OBJECTIVES: To demonstrate a consequence of overadvancement of a Steinmann pin (guide wire). SUMMARY OF BACKGROUND DATA: Although intraoperative tension pneumothorax is admitted to be a theoretical complication of video-assisted surgery for anterior correction of idiopathic scoliosis, there has yet to be a case reported in the literature. This report presents the first case of this complication. METHODS: A 13-year-old girl who had right thoracic scoliosis with a curve measuring 54 degrees underwent video-assisted surgery discectomy and anterior spinal fusion with instrumentation of T5 through T11. Single-lung ventilation had been achieved with a double-lumen tube and the right lung was deflated. After approximately 4.5 hours of complication-free surgery, intraoperative fluoroscopy showed an approximately 2-cm overadvancement of a guide wire into the opposite hemithorax. Approximately 5 minutes after the overadvancement was corrected, the patient experienced a gradual increase in heart rate and a corresponding gradual decrease in oxygen saturation and both systolic and diastolic blood pressures. Approximately 35 minutes later, it was determined that the patient had sustained a tension pneumothorax of the left hemithorax. RESULTS: The patient underwent urgent partial reinflation of the right lung and a tube thoracostomy of the left thoracic cavity. Vital signs quickly returned to stable levels, and the left lung easily reinflated with the chest tube suction. The patient remained stable after the procedure was resumed (by right lung deflation). The remainder of the surgery and the postoperative course were uneventful. CONCLUSIONS: Although video-assisted surgery continues to gain popularity in the management of spinal deformities, the surgical team must be certain to pay meticulous attention to detail throughout the procedure. The early detection and treatment of complications can be life-preserving.

Traumatic hip dislocation in children. Long-term followup of 42 patients.

To assess the impact of traumatic hip dislocations in the skeletally immature patient, 42 children younger than 16 years of age (average age, 9 years 10 months) who were treated at the authors' institution were studied. Data were collected from charts and radiographs and by completion of questionnaires. The average followup after injury was 10 years 1 month. The majority of dislocations (64%) were attributable to low energy injuries. Ipsilateral fractures about the hip occurred in 17% of patients. Avascular necrosis of the femoral head developed in 12% of patients, with the amount of time spent dislocated being the only statistically proven risk factor. Patients whose reduction was delayed greater than 6 hours had a 20 times higher risk of having avascular necrosis develop compared with patients whose hips were reduced in 6 hours or less. The use of computed tomography for joint asymmetry of 3 mm or greater and omission of bone scan screening were supported by this study. Functional outcomes were very good in this series with 95% of patients suffering mild (usually weather related) or no pain and 95% of patients suffering mild pain (intermittently noticeable) or no limp. A large percentage of the patients (78%) continued to participate in high demand activities such as football, soccer, and basketball.

Modulation of spinal deformities in patients with neurofibromatosis type 1.

STUDY DESIGN: A consecutive case retrospective chart and radiographic review. OBJECTIVES: To determine the incidence of nine radiographic dystrophic features acquired during the process of modulation, and to analyze the statistical correlation of these acquired dystrophic features with clinical progression of a spinal deformity. SUMMARY OF BACKGROUND DATA: In patients with neurofibromatosis, spinal deformities with seemingly few initial dystrophic features have shown a tendency to acquire dystrophic changes during long-term follow-up periods. Similarly, deformities with dystrophic changes can acquire further dystrophic features. This phenomenon is termed "modulation," a feature unique to spinal deformities in neurofibromatosis. These dystrophic changes may evolve slowly or aggressively, and may spread to other regions as well. METHODS: A review was done of the clinical records, photographs, radiographs, and other imaging studies of 457 patients referred between 1982 and 1995 with the diagnosis of neurofibromatosis Type 1. One hundred twenty-eight patients were diagnosed with a spinal deformity. Ninety-one patients who had a complete set of clinical and radiographic data were included in the study. Location and type of curve as well as the extent of spinal deformity were studied for their effect on the tendency for modulation. Initial spinal radiographs were analyzed for nine radiographic dystrophic features: rib penciling, vertebral rotation, posterior vertebral scalloping, anterior vertebral scalloping, lateral vertebral scalloping, vertebral wedging, spindling of the transverse process, widened interpedicular distance, and enlarged intervertebral foramina. Subsequent radiographs were analyzed critically for evolution, progression, or spread of these features. Correlation of acquisition in these dystrophic features with clinical progression in the spinal deformity, as measured in increments of scoliosis and kyphosis, was analyzed. RESULTS: In 81% of patients with spinal deformity diagnosed before 7 years of age and in 25% of patients with such a diagnosis after 7 years of age, evidence of modulation was observed. Location, side, and extent of the deformity and patient gender did not influence the propensity of the deformity to modulate. Correlation of modulation with clinical progression of the deformity showed rib penciling to be the only singular factor statistically influencing risk of progression. Of the deformities that acquired three or more penciled ribs, 87% showed significant clinical progression. No other radiographic dystrophic feature individually influenced progression. However, when three or more of the dystrophic skeletal features were acquired, the risk of progression reached statistical significance in 85% of patients. CONCLUSIONS: Spinal deformities in patients with neurofibromatosis 1 should be regarded as deformities in evolution. One should resist assigning these evolving deformities to either the dystrophic or nondystrophic end of the spectrum without considering the possibility of modulation across the spectrum. A spinal deformity that develops before 7 years of age should be followed closely for evolving dystrophic features (i.e., modulation). When a curve acquires either three penciled ribs or a combination of three dystrophic features, clinical progression is almost a certainty.