Spinal Cord Swelling as a Myelographic Indicator of Prognosis: A Retrospective Study in Dogs With Intervertebral Disc Disease and Loss of Deep Pain Perception

The association of myelographic spinal cord swelling with neurological outcome was examined in 46 dogs with intervertebral disc disease and absence of deep pain perception (DPP). Spinal cord swelling was measured by calculating a ratio of the length of the loss of the myelographic dye column to the length of the second lumbar vertebra (L2). A positive neurological outcome was defined as return of voluntary motor function. A cut-off value for swelling:L2 of 5.0 was established by the creation of a receiver operator characteristic curve. Using a swelling:L2 ratio of 5.0 as a cutoff for indication of neurological recovery yielded a sensitivity of 74% and a specificity of 61%. Overall neurological recovery rate was 43%. Dogs with spinal cord swelling: L2 ratios less than 5.0 had a recovery rate of 61%, whereas dogs with a ratio greater than or equal to 5.0 had a recovery rate of 26%. Evaluation of these data by chi square analysis confirmed that a ratio less than 5.0 was associated with a positive outcome, and a ratio greater than or equal to 5.0 was associated with a negative outcome, ( P <.05). Although other factors, such as duration of neurological signs, affect neurological outcome in dogs with no DPP, evaluation of myelographic spinal cord swelling can assist in establishing a prognosis.     

Clinical Characteristics of Dogs with Progressive Myelomalacia Following Acute Intervertebral Disc Extrusion

Background

Progressive myelomalacia (PMM) is a catastrophic disease associated with acute intervertebral disc extrusion (IVDE). Published data on the clinical characteristics of this disease are limited.

Objective

To describe the onset and progression of clinical signs of PMM in a large case cohort.

Animals

Fifty‐one dogs, 18 with histopathologically confirmed PMM, 33 presumptively diagnosed based on clinical signs and diagnostic imaging.

Methods

Retrospective study. Dogs with confirmed IVDE and either a histopathologic diagnosis of PMM or a high clinical suspicion were identified by medical record search. Data on nature and progression of signs were extracted.

Results

Twenty‐four of 51 dogs were Dachshunds. T12–T13 was the most common site of disc extrusion (12 of 56), and 18 of 55 of mid‐to‐caudal lumbar discs (between L3 and L6) were affected. Onset of PMM signs ranged from present at first evaluation (17/51) to 5 days after presentation, with 25 of 51 cases developing signs within 48 hours. Progression of signs from onset of PMM to euthanasia or death, excluding 7 cases euthanized at presentation, ranged from 1 to 13 days with 23 being euthanized within 3 days. Nonspecific systemic signs were documented in 30 of 51 dogs.

Conclusion and Clinical Importance

The majority of dogs developed PMM within 2 days of presentation and was euthanized within another 3 days. However, onset can be delayed up to 5 days after presentation with progression to euthanasia taking as long as 2 weeks. Mid‐to‐caudal lumbar discs might be associated with an increased risk of PMM.     

Prevalence of Urinary Tract Infection in Dogs after Surgery for Thoracolumbar Intervertebral Disc Extrusion

Background: Urinary tract infection (UTI) is a common complication in people with spinal cord injury (SCI). Dogs with acute intervertebral disc extrusion (IVDE) have similar risk factors for UTI when compared with human SCI patients and have a high perioperative prevalence of UTI. Objectives: Determine the prevalence of UTI in dogs for 3 months after surgery for thoracolumbar IVDE and identify risk factors for development of UTI. Animals: Twenty‐five dogs treated surgically for 26 acute disc extrusions. Methods: Prospective study. Urinalysis and urine culture were performed perioperatively. At home, owners monitored urine with dipsticks every 48 hours for 1 month then once a week until 3 months. Dogs returned for assessment of motor function, urinalysis, and urine culture at 1 and 3 months after surgery. Presence of UTI over the 3‐month period was correlated to potential risk factors. Results: Ten dogs (38%) developed 12 UTIs over the 3‐month period, with the majority occurring between weeks 1 and 6; 60% of the UTIs were occult. Hematuria in the absence of pyuria or UTI was a common finding in the perioperative period. Sex, breed, and ambulatory status influenced the risk of developing a UTI. Conclusions and Clinical Importance: There is a high prevalence of UTIs, many of which are occult, in the 3 months after surgery for thoracolumbar IVDE. These dogs should be routinely monitored for UTI with urine culture regardless of urinalysis results.     

Dorsal Decompressive Laminectomy for Treatment of Thoracolumbar Disc Disease in Dogs: A Retrospective Study of 98 Cases

This study reviews the records of all dogs that underwent dorsal decompressive laminectomy for thoracolumbar disc disease at the Angell Memorial Animal Hospital during a 2-year period. Findings as to age, breed, sex, and site of disc protrusion did not differ from those published by others. All dogs were operated on within 36 hours of the onset of inability to walk. The overall recovery rate was 80.6%. The recovery rate of dogs that had preoperative sensory perception was 89.5%, but was only 50.0% for those without sensory perception. The most important factor determining recovery rate was the presence or absence of preoperative sensory perception.     

Agreement between T2 and haste sequences in the evaluation of thoracolumbar intervertebral disc disease in dogs

The purpose of this study was to compare half-Fourier-acquisition single-shot turbo spin-echo (HASTE) and T2-weighted (T2-W) sequences in dogs with thoracolumbar disc extrusion. MRI studies in 60 dogs (767 individual intervertebral disc spaces) were evaluated. Agreement between T2-W and HASTE sequences was assessed for two criteria: presence of an extradural lesion and treatment recommendation. There was moderate agreement between T2-W and HASTE sequences as to presence of an extradural lesion (kappa = 0.575). HASTE was in agreement in 96.1% of the sites where no extradural lesion was identified on T2-W images, but only in 58.1% of the sites where extradural lesions were identified on T2-W images. There was also moderate agreement between T2-W and HASTE sequences as to treatment recommendations (kappa = 0.476). HASTE was in agreement in 98.4% of the sites where a lesion was considered nonsurgical on T2 but only 82.1% of sites a lesion was considered surgical on T2. In 1.0% of sites considered not surgical and in 9.8% of sites considered equivocal based on T2-W images, a surgical lesion was identified on HASTE. Acquisition of a HASTE sequence in addition to conventional sequences may be beneficial in determining the severity of spinal cord compression in some cases when evaluating the canine spine.     

针灸治疗犬椎间盘突出症90例(2000-2002)

对90例犬椎间盘突出症病例进行了总结性回顾，经针灸治疗有81例取得了很好的疗效，有效率为90％，但对于临床分级为四级的病例的疗效较低，仅为45．5％，但是针灸疗法对于提高患犬的食欲、精神状态和降低疼痛方面具有很好的作用。总之，采取中医针灸的治疗方法是一种有效的、经济的治疗方法。该种疗法是值得推广和发扬的中国中兽医的传统治疗方法。     

犬椎间盘病治疗中常用抗炎药物合理应用研究

犬椎间盘病（IVDD）继发性损伤中的炎症反应过程复杂,临床中如何选用相应药物成为了治疗难点。目前临床常用的两大类用于椎间盘病抗炎治疗的药物包括甾体类与非甾体类抗炎药（NSAIDs）,它们的使用一直以来存在很大的争议。因此,了解它们各自的药理特性十分重要,本文结合这两大类药物作用机制及疗效研究展开了对二者的合理用药分析,以期为临床IVDD抗炎药物的选用提供一定参考。     

Complications of Methylprednisolone Sodium Succinate Therapy in Dachshunds with Surgically Treated Intervertebral Disc Disease

Objective: To compare the incidence of clinically evident post-operative complications, financial cost and length of hospital stay for Dachshunds with acute intervertebral disc disease treated with decompressive surgery with and without the use of methylprednisolone sodium succinate (MPSS).
Design: Retrospective clinical study
Setting: Veterinary Teaching Hospital
Animals: Dachshunds that presented to the Veterinary Hospital of the University of Pennsylvania between January 1994 and December 1999 with acute intervertebral disc disease that were treated with decompressive surgery.
Intervention: None
Measurements and Main Results: Dogs were divided into 2 groups dependent upon whether they had received MPSS. Medical records were examined for evidence of post-operative complications. Other parameters recorded included details of drugs administered (principally corticosteroids and gastrointestinal protectant drugs), length and cost of hospital stay and neurological status at 24 hours post-operatively and at suture removal. Compared to other corticosteroids, dogs receiving MPSS had a significantly higher incidence of clinically evident post-operative gastrointestinal complications, an increased use of gastrointestinal protectant drugs, and an increased cost for hospital stay (p<0.01).
Conclusions: The use of MPSS inDachshunds with acute intervertebral disc disease is associated with an increased post-operative complication rate and an increased financial cost to the client. The use of MPSS should be carefully evaluated for each patient.     

MRI features can help to confirm a diagnosis of progressive myelomalacia,but may not be accurate in dogs lacking characteristic clinical signs at the time of imaging

Progressive myelomalacia (PMM) is a fatal sequela of acute thoracolumbar intervertebral disc extrusion in dogs, with unpredictable onset in the days after the inciting injury. No single reliable diagnostic test is currently available. Magnetic resonance imaging (MRI) features such as T2-weighted spinal cord hyperintensity and loss of subarachnoid signal in a half-Fourier single-shot turbo spin echo (HASTE) sequence have been associated with PMM, but are sometimes present in other dogs with severe deficits. Magnetic resonance imaging findings in 22 dogs with a clinical or histopathologic diagnosis of PMM and 38 deep pain-negative paraplegic dogs were compared in a retrospective case-control study. Length of T2-weighted hyperintense spinal cord change and HASTE signal loss were significantly associated with clinically evident PMM (P = .0019 and P = .0085), however, there were no significant differences between groups when analysis was restricted to dogs not yet showing clinical signs of PMM. The PMM group also had significantly shorter compressive lesions than the control group (P = 0.026), suggesting a possible role of more severe focal pressure at the extrusion site. A segment of total loss of contrast enhancement in the venous sinuses and meninges, a feature not previously described, was more common in the PMM group and the difference approached significance (P = 0.054). Findings show that MRI features can support the diagnosis in dogs with clinical evidence of PMM, and absence of these features supports absence of PMM at time of imaging. However, their absence does not reliably differentiate dogs with imminent progressive myelomalacia from other dogs with severe deficits following intervertebral disc extrusion.     

Investigations of the Therapeutig and Prophylactic Effects of Disc Evacuation in Cases of Thoraco-Lumbar Herniated Discs in Dogs

The author describes a method for the fenestration and evacuation of degenerated discs in the thoraco-lumbar region of the dog using a lateral approach. This lateral approach makes it possible to reach the entire area of the nucleus pulposus. With the method described, all of the discs in the region of T₉/T₁₀—L₅/L₆ can be evacuated at the same time. The author presents 88 operated cases which showed light or moderate signs of thoraco-lumbar disc herniation, i.e. dogs which displayed pain and/or varying grades of paresis, but retained the ability to walk on their hind legs. The author compares the results of this surgical treatment with the results of the conservative treatment of 128 cases. No significant difference in respect to the mean recovery time was seen between the 2 groups, but the progression of the attack into paraplegia did not occur in the surgically treated material, while such a progression was seen in 4 cases in the conservative material. The greatest value of the disc evacuation, according to the author''s investigations, seems to be its prophylactic effect against recurrence. If all of the radiologically degenerated discs in the affected area are evacuated, it appears that one achieves almost complete prophylaxis for some years.     

Correlation of Clinical, Radiographic, and Surgical Localization of Intervertebral Disc Extrusion in Small-Breed Dogs: A Prospective Study of 50 Cases

Objective —To compare prospectively clinical, radiographic, and surgical findings of intervertebral disc extrusion (IDE) localization in small-breed dogs and to determine the best means of lesion localization for the purpose of hemilaminectomy. Study Design —Clinical, radiographic, and surgical findings of small-breed dogs with thoracolumbar IDE were prospectively compared for agreement on lesion localization. Sample Population—50 small-breed dogs with IDE treated at the three participating veterinary hospitals were included in the study if no other confounding diseases were identified and if the owner gave permission for diagnostic tests and surgery. Methods —Clinical and surgical findings were recorded by the surgeon assigned to the case. Radiographic studies were evaluated independently by two radiologists blinded as to the clinical and surgical findings. values and 95% confidence intervals were calculated for agreement on lesion localization by clinical, radiographic, and surgical means and for agreement between radiologists. Results —K values for agreement of lesion localization were as follows: clinical versus surgical, 0.595; radiologist A versus radiologist B, 0.81; radiologist A versus surgical findings, 0.60; radiologist B versus surgical findings, 0.71. Both radiologists' interpretation of IDE localization agreed with surgical localization in 60% of cases. Conclusions —Clinical lateralization of IDE was found to be the least reliable factor of those studied for determining on which side the hemilaminectomy should be performed. Results of this study differ from those of previous studies examining the reliability of myelography to localize the site of IDE accurately. The results of this study further suggest that surgery may not be an absolute standard for determination of the localization of IDE in small-breed dogs. Clinical Relevance —Intervertebral disc extrusion in small-breed dogs frequently results in bilateral distribution of extruded material. Computed tomography or magnetic resonance imaging may be necessary to delineate completely the distribution of extruded disc material in IDE.     

Thoracolumbar lateral corpectomy for treatment of chronic disk herniation: technique description and use in 15 dogs

OBJECTIVE: To describe a technique for thoracolumbar lateral corpectomy and to evaluate its use for treatment of chronic thoracolumbar disk disease in dogs. STUDY DESIGN: Retrospective study. ANIMALS: Fifteen dogs with signs of chronic thoracolumbar disk herniation. METHODS: After a dorsal or lateral approach to the spine, a lateral slot was created in 2 adjacent vertebral bodies on either side of the herniated disk and extruded/protruded material was removed. Data collected included history, duration of clinical signs, presurgical assessment of neurologic status, postsurgical neurologic status, complications, and outcome. RESULTS: Ambulatory capacity was maintained or regained, and neurologic status improved by 1 grade (3 dogs), 2 grades (8), 3 grades (2), or 4 grades (2). Eleven dogs were considered free of disease. A seroma in 1 dog was the sole complication observed. CONCLUSIONS: Lateral corpectomy permits relatively easy removal of protruded-extruded disk material from within the vertebral canal in chronic disk disease without further iatrogenic injury to the spinal cord. CLINICAL RELEVANCE: Lateral corpectomy is an alternative to dorsal decompression for treatment of ventral and lateroventral thoracolumbar chronic disk disease in dogs.     

Transplantation of adipose derived mesenchymal stem cells for acute thoracolumbar disc disease with no deep pain perception in dogs

Thirty-four dogs with no deep pain perception due to acute thoracolumbar intervertebral disc disease underwent decompression surgery within 1 week of diagnosis. All dogs underwent hemilaminectomy. Adipose derived mesenchymal stem cells (AD-MSCs) were transplanted into the injured spinal cord parenchyma for the AD-MSCs transplant dogs. Long-term outcome was evaluated at the end of the follow-up period (> 6 months). AD-MSCs combination treatment showed better recovery outcomes compared to decompression surgery alone. These results indicate that this stem cell therapy is a potential therapeutic strategy to overcome the limitations of treatment for spinal cord injury in clinical medicine.