Perioperative analgesic effects of the erector spinae plane block with bupivacaine or bupivacaine-dexmedetomidine in dogs undergoing hemilaminectomy: A randomized controlled trial.

Objective: To compare the perioperative opioid requirements among dogs receiving an erector spinae plane (ESP) block with bupivacaine, with or without dexmedetomidine, and a control group. Animals and procedure: Thirty client-owned, healthy adult dogs undergoing hemilaminectomy were included in this randomized, prospective, blinded clinical study. Dogs were randomly assigned to 1 of 3 treatment groups: Group B, ESP block with bupivacaine; Group BD, ESP block with bupivacaine and dexmedetomidine; and Group C, control. Rescue intra- and postoperative analgesia consisted of fentanyl and methadone, respectively. Postoperative pain was evaluated using the short form of the Glasgow Composite Measure Pain Scale (CMPS-SF). Results: In Group BD, 0/10 dogs required intraoperative fentanyl, compared to 9/10 in Group C (P < 0.001), whereas 1/10 required postoperative methadone, compared to 9/10 in Group B (P = 0.003) and 10/10 in Group C (P < 0.001). The total amount of intraoperative fentanyl (µg/kg) was 0 (0 to 4) in Group B and 0 (0 to 0) in BD, compared to 6 (0 to 8) in C (P = 0.004 and P < 0.001, respectively). Postoperative methadone (mg/kg) required during the first 12 h was 0.5 (0 to 1.4) in Group B (P = 0.003) and 0 (0 to 0) in BD (P < 0.001), compared to C (P = 0.003 and P < 0.001, respectively). Conclusion: An ESP block with bupivacaine, with or without dexmedetomidine, was associated with a reduction in perioperative opioid consumption and provided effective acute pain control.

Effets analgésiques périopératoires du bloc des érecteurs du rachis avec de la bupivacaïne ou de la bupivacaïne-dexmédétomidine chez les chiens subissant une hémilaminectomie: un essai contrôlé randomisé. Objectif: Comparer les besoins périopératoires en opioïdes chez les chiens recevant un bloc des érecteurs de la colonne vertébrale (ESP) avec de la bupivacaïne, avec ou sans dexmédétomidine, et un groupe témoin. Animaux et procédure: Trente chiens adultes en bonne santé appartenant à des clients subissant une hémilaminectomie ont été inclus dans cette étude clinique randomisée, prospective et en aveugle. Les chiens ont été répartis au hasard dans 1 des 3 groupes de traitement: groupe B, bloc ESP avec bupivacaïne; groupe BD, bloc ESP avec bupivacaïne et dexmédétomidine; et groupe C, témoin. L'analgésie de secours peropératoire et postopératoire consistait respectivement en fentanyl et en méthadone. La douleur postopératoire a été évaluée à l'aide du formulaire abrégé de l'échelle de mesure de la douleur de Glasgow (CMPS-SF). Résultats: Dans le groupe BD, 0/10 chiens ont eu besoin de fentanyl peropératoire, contre 9/10 dans le groupe C (P < 0,001), tandis que 1/10 ont eu besoin de méthadone postopératoire, contre 9/10 dans le groupe B (P = 0,003) et 10/10 dans le groupe C (P < 0,001). La quantité totale de fentanyl peropératoire (µg/kg) était de 0 (0 à 4) dans le groupe B et de 0 (0 à 0) dans le groupe BD, contre 6 (0 à 8) dans le groupe C (P = 0,004 et P < 0,001, respectivement). La méthadone postopératoire (mg/kg) nécessaire au cours des 12 premières heures était de 0,5 (0 à 1,4) dans le groupe B (P = 0,003) et de 0 (0 à 0) dans le groupe BD (P < 0,001), par rapport au groupe C (P = 0,003). et P < 0,001, respectivement). Conclusion: Un bloc ESP avec de la bupivacaïne, avec ou sans dexmédétomidine, a été associé à une réduction de la consommation peropératoire d'opioïdes et a permis un contrôle efficace de la douleur aiguë.(Traduit par Dr Serge Messier).

Erector spinae plane block in dogs undergoing hemilaminectomy: A prospective randomized clinical trial.

OBJECTIVE: To compare the perioperative cumulative opioid consumption and the incidence of cardiovascular complications in dogs undergoing hemilaminectomy in which either an erector spinae plane (ESP) block or systemic opioids were administered. STUDY DESIGN: Prospective randomized clinical trial. ANIMALS: A total of 60 client-owned dogs. METHODS: Dogs were randomized to one of three groups: an ESP block (group ESP), a constant rate infusion of fentanyl (group FNT, positive control) or a single dose of methadone as premedication (group MTD, negative control). Intraoperative nociceptive response was treated with fentanyl [1 µg kg-1, intravenously (IV)] boli. Before closure of the surgical site, morphine (0.1 mg kg-1) was applied to the dura mater. The cumulative dose of opioids was recorded and compared between groups. The incidence of intraoperative bradycardia and/or hypotension and the time to extubation were compared between groups. The short form of the Glasgow Composite Pain Scale (SF-GCPS) was used to score nociception before anaesthetic induction and 1, 2, 6, 12,18 and 24 hours postoperatively. Methadone 0.2 mg kg-1 was administered IV if the SF-GCPS score was ≥ 5. RESULTS: Group MTD required more intraoperative rescue analgesia than groups ESP (p = 0.008) and FNT (p = 0.001). The total cumulative intraoperative dose of fentanyl was higher in groups FNT (p < 0.0001) and MTD (p = 0.002) than in group ESP. The incidence of cardiovascular complications was similar between groups. Extubation time was longer in group MTD (p = 0.03). Postoperatively, the time to first rescue analgesia was longer in group ESP than in group MTD (p = 0.03). The cumulative postoperative opioid consumption and pain scores were similar between groups. CONCLUSIONS AND CLINICAL RELEVANCE: The ESP block resulted in a reduced intraoperative opioid consumption compared with the control positive and negative groups.

Thoracic Vertebral Canal Stenosis and Vertebral Instability in a Young Minuet Cat.

This report describes a unique case of thoracic vertebral canal stenosis and vertebral instability in a 1 yr old Minuet cat. The cat presented with a history of chronic progressive nonambulatory paraparesis. Myelography with neutral and stress positions revealed dynamic compression at T1-4. Computed tomography and MRI revealed multiple sites of vertebral endplate osteolysis, adjacent bone sclerosis, intervertebral disk space narrowing, and spondylotic bridging within the cervical and cranial thoracic vertebral bodies and pedicles, particularly at C6-T4. The cat underwent a right-sided T1-4 hemilaminectomy and C7-T4 vertebral stabilization using positively threaded profile pins and polymethylmethacrylate. The cat fully recovered without any complication. The case highlights the potential for young cats, especially those with a chondrodysplastic condition, to develop vertebral canal stenosis and vertebral instability. The surgical treatment described herein resulted in an excellent outcome.

Clinical features of early recurrence of type I thoracolumbar intervertebral disk herniation in Miniature Dachshunds.

Some reports have been published on clinical features in dogs with early recurrence of type I thoracolumbar intervertebral disk herniation (TL-IVDH), but there is little understanding of the changes involved. This retrospective study describes the clinical features, including radiographic image results at the time of recurrence, of dogs with type I TL-IVDH that had undergone hemilaminectomy but then suffered early recurrence. Our medical records were searched between June 2007 and December 2022. Nine dogs showed deterioration in neurological signs within 4 to 6 weeks after surgery. All nine were Miniature Dachshunds. Radiographic images at initial onset showed calcification at the affected intervertebral disk space in all 9 dogs. Disk herniations at the initial onset were located between T11-12 and L1-2. After the first surgery, neurological function improved in all dogs. Recurrence occurred at the same site as at initial onset in all dogs. No calcification was observed at the affected intervertebral disk space on images at the time of recurrence. The extruded disk materials were surgically removed, and neurological function improved after the second surgery. In conclusion, calcification at the affected disk space at the time of initial onset is indicative of residual nucleus materials not yet fully extruded, and is a risk factor for early recurrence of type I TL-IVDH.

Scapular Osteotomy for Lateral Access to a T1-2 Foraminal Disc Extrusion, Treated by Mini-Hemilaminectomy in a Dog.

A 4-year-old female spayed French bulldog was presented with a 2-day history of neck pain and left thoracic limb lameness with no neurological deficits. A computed tomography (CT) examination showed a left foraminal T1-2 disc extrusion. Surgical management was performed using a left lateral approach to the vertebral column with a scapular osteotomy. A T1-2 mini-hemilaminectomy was performed. The scapular osteotomy was stabilized with two 2.4-mm locking compression plates. The postoperative CT and radiographic examinations showed adequate decompression of the T1-2 foramen and good reduction in the scapular osteotomy. The dog was able to walk the following day. At the 1-month follow-up, the dog had no neck pain but persistent slight left thoracic limb lameness. Ten months postoperatively, a CT scan showed no abnormalities at the surgical site, and the dog had no neurological deficits nor lameness. The aim of this case report was to describe a new lateral approach to T1-2 intervertebral space.

A feline spinal dermoid cyst treated with surgical intervention.

A 5-year-old neutered female mixed cat presented with reduced activity and ataxia of the hind limbs. Computed tomography and magnetic resonance imaging revealed an extradural mass compressing the spinal cord on the dorsal aspects from the 7th to 8th thoracic vertebra. Dorsal laminectomy was performed on the 7-8th thoracic vertebra and the cyst was totally removed, giving full resolution of the clinical signs. The cyst was diagnosed as a dermoid cyst. To our knowledge, this is the first report of feline dermoid cyst compressing the spinal cord that was diagnosed antemortem. The prognosis is favorable when the cyst is completely resected.

IV Versus Myelography Computed Tomography for Thoracolumbar Intervertebral Disc Extrusion Surgical Planning in French Bulldogs.

Accurate diagnostic imaging is required for surgical planning of acute thoracolumbar intervertebral disc extrusion. However, data comparing the accuracy of conventional IV contrast-injected computed tomography (CT) and myelography CT for hemilaminectomy localization and size assessment are sparse. In this study, IV contrast-injected CT and myelography CT were performed in 48 French bulldogs presenting with acute disc herniation and compared with postsurgical CT. CT images were evaluated by three raters. IV contrast-injected CT erroneously identified the compressive lesion site significantly more often than myelography CT. The length of the compressive lesion was significantly higher using myelography CT compared with conventional CT, but this did not lead to relevant consequences on the surgical opening site length. Myelography CT should therefore be recommended when thoracolumbar disc disease is suspected and multiple compressive lesions are visualized on IV-injected CT in French bulldogs.

Tridimensional models and radiographic study of dorsal laminectomy and thoracolumbar hemilaminectomy in dogs.

PURPOSE: To create three-dimensional anatomical models of the thoracic and lumbar portions of the canine spine that reproduce the vertebral surgical approaches of dorsal laminectomy and hemilaminectomy, and to perform the respective radiographic evaluations of each approach. METHODS: In a digital archive of the canine spine, digitally replicate the dorsal laminectomy and hemilaminectomy in the thoracic and lumbar portions and, then, make tridimensional prints of the vertebral models and obtain radiographs in three dorsoventral, ventrodorsal and laterolateral projections. RESULTS: The anatomical models of the surgical spinal canal accesses of the thoracic and lumbar portions showed great fidelity to the natural bones. The created accesses have the proper shape, location and size, and their radiographic images showed similar radiodensities. CONCLUSIONS: The replicas of the dorsal laminectomy and hemilaminectomy developed in the anatomical models in the thoracic and lumbar portions are able to represent the technical recommendations of the specialized literature, as well as their respective radiographic images, which have certain radiological properties that allow to make a deep radiological study. Therefore, the models are useful for neurosurgical training.

Decompressive laminectomy with vertebral stabilization allows neurologic improvement of most Pekingese dogs with thoracolumbar vertebral instability.

OBJECTIVE: To describe the diagnostic findings, surgical techniques, and outcomes of thoracolumbar vertebral instability associated with or without articular process (AP) anomalies in Pekingese dogs. ANIMALS: 11 client-owned Pekingese dogs. PROCEDURES: Medical records (2007 to 2022) were reviewed. Inclusion criteria were Pekingese dogs with thoracolumbar vertebral instability that underwent decompressive laminectomy and vertebral stabilization. Dynamic myelographic study and/or intraoperative spinal manipulation were used to diagnose vertebral instability. Data on preoperative and postoperative neurologic status, diagnostic findings, surgical techniques, and outcomes were retrieved. RESULTS: The dogs presented with paraparesis (n = 9) or paraplegia (2). Five dogs had caudal AP anomalies. Dynamic myelographic study demonstrated single (n = 7) or multiple (4) dynamic compressions with poststress spinal cord height reduction (median, 12.5%; IQR, 6.8% to 21.2%). Of the 17 dynamic compression lesions, 5 lesions were at the disc spaces with caudal AP abnormalities. All dogs had vertebral instability confirmed by intraoperative spinal manipulation and underwent hemilaminectomy and unilateral vertebral stabilization. One dog had adjacent segment vertebral instability and underwent vertebral stabilization 3 months after the initial operation. All but 1 dog showed successful outcomes at the last follow-up (median, 16 months; IQR, 3 to 32 months). CLINICAL RELEVANCE: Vertebral instability associated with or without AP abnormalities is a potential cause of thoracolumbar spinal cord injury in Pekingese dogs. Dynamic myelographic studies and/or intraoperative spinal manipulation demonstrated vertebral instability. Spinal cord decompression and vertebral stabilization are effective, resulting in neurologic improvements in most dogs.

Unique cytologic and imaging features of a lumbosacral oligodendroglioma in a cat.

A 12-y-old castrated male domestic longhaired cat had progressive paraparesis and neurolocalization of L4-S3. MRI revealed a circumscribed intradural-extraparenchymal mass from L5 to S1 that was T2 and short tau inversion recovery hyperintense and strongly contrast-enhancing. Cytologic interpretation of a blind fine-needle aspirate obtained through the L5-L6 space was a tumor of probable mesenchymal origin. A pair of suspect neoplastic cells was seen on a cytocentrifuged preparation of the atlanto-occipital CSF sample, despite a normal nucleated cell count (0 × 106/L) and total protein (0.11 g/L) with only 3 RBCs × 106/L. Clinical signs progressed despite increasing doses of prednisolone and cytarabine arabinoside. Repeat MRI on day 162 demonstrated tumor progression from L4 to Cd2 vertebral segments with intraparenchymal extension. Surgical tumor debulking was attempted, but an L4-S1 dorsal laminectomy revealed diffusely abnormal neuroparenchyma. Intraoperative cryosection favored lymphoma, and the cat was euthanized intraoperatively 163 d following presentation. Postmortem examination was performed, and the final diagnosis was a high-grade oligodendroglioma. This case illustrates the cytologic, cryosection, and MRI features of a unique clinical presentation of oligodendroglioma.

An extradural cyst in a French Bulldog.

CASE HISTORY: A 7-year-old, male neutered French Bulldog was referred to a specialist veterinary hospital for evaluation of progressive paraparesis of 6-months' duration. The owners reported both faecal and urinary incontinence at home. CLINICAL FINDINGS: The dog presented with ambulatory paraparesis and pelvic limb ataxia that was more pronounced in the right pelvic limb. The pelvic limb withdrawal response and sciatic myotatic response were reduced bilaterally. Postural reaction responses were delayed in both pelvic limbs, and this was more obvious in the right pelvic limb. The anal tone and perineal sensation were normal at the time of examination.An L4-S3 myelopathy was suspected. CT of the spine revealed a compressive, bilobed, extramedullary, cyst-like structure within the vertebral canal, between L7 and S3. Surgical removal of the cyst via a L7-S1 dorsal laminectomy was performed. Histopathological examination and additional immunohistochemistry of the excised structure indicated a probable ependymal cyst with a ciliated lining. The dog recovered well post-operatively, and at follow-up 3 weeks later had some improvement of his neurological signs. The paraparesis and pelvic limb ataxia had improved; however, the remaining neurological examination was similar to the pre-surgical examination. DIAGNOSIS: Extradural cyst. CLINICAL RELEVANCE: Spinal cysts can contribute to clinical signs that resemble other common chronic spinal cord diseases, such as intervertebral disc disease. Therefore, this disease should be considered as a differential when dealing with cases of progressive paraparesis and pelvic limb ataxia. This case report may potentially provide opportunities in the future for further understanding of the pathogenesis, behaviour, outcomes and subclassification of spinal cysts in dogs.

Continuous hemilaminectomy of nine vertebrae can be performed safely in large breed dogs: A case report of a German Shepherd Dog with intervertebral disc extrusion and extensive extradural hemorrhage.

Background: Extended, continuous hemilaminectomy has only been reported in small to medium-sized dogs so far. It remains unclear whether excessive continuous hemilaminectomy can also be performed safely in large breed dogs. Case Description: We describe the surgical treatment and clinical outcome of a 5-year-old German Shepherd Dog that presented with paraplegia and deep pain perception following a short episode of bilateral hind-limb lameness, secondary to jumping off of a car. Computed tomography-myelography revealed that the paraplegia originated from extensive extradural spinal cord compression (Th6-L1), due to intervertebral disc extrusion and associated epidural hemorrhage. The dog was treated with a continuous hemilaminectomy involving nine vertebrae (Th6-L1) and recovered completely with no remaining neurological deficits, within 6 months. Conclusion: The rapid, uncomplicated, and complete functional recovery in the presented case emphasizes the practicability of extensive, continuous hemilaminectomies, also in large breed dogs.

Postoperative outcomes of combined surgery comprising dorsal laminectomy, transarticular screws, pedicle screws and polymethylmethacrylate for dorsal fixation in 21 dogs with degenerative lumbosacral stenosis.

OBJECTIVE: To retrospectively review the efficacy of combined surgery comprising dorsal laminectomy and dorsal fixation using screws and polymethylmethacrylate as treatment for dogs with degenerative lumbosacral stenosis (DLSS). ANIMALS: 21 client owned dogs diagnosed with DLSS and treated surgically. PROCEDURES: Based on clinical records, signalments, clinical signs, findings from orthopedic and neurological examinations, imaging findings, and postoperative complications were evaluated at the following time points: preoperatively, postoperatively, and 3, 6, 12, 24, and 36 months after surgery. RESULTS: In all 21 cases, clinical signs were alleviated, proprioceptive deficits were improved from 3 months after surgery, and no recurrence of clinical signs was observed during the observation period. Minor complications were observed in 6 cases (28.6%), including implant failure in 2 (9.5%), delayed healing of surgical wounds in 2 (9.5%), seroma in 1 (4.8%), and swelling of the affected area in 1 (4.8%). There was no case with major complications. CLINICAL RELEVANCE: Combined surgery comprising dorsal laminectomy and dorsal fixation using screws and polymethylmethacrylate is a useful treatment that can improve long-term clinical signs in dogs with DLSS.

Spinal epidural arteriovenous fistula in 3 cats.

Three young adult cats with intermittent spinal hyperesthesia and paraparesis and diagnosed with spinal epidural arteriovenous fistula are described. In all 3 cases, magnetic resonance imaging (MRI) showed focal dilatation of the veins in the epidural space of the thoracic spinal cord, whereas computed tomography angiography (CTA) showed dilatation and enhancement from the intercostal vein to the azygos vein at the same site in the arterial phase. Dorsal laminectomy and occlusion of the interarcuate branches running across the dorsal aspect of the spinal cord were performed in all 3 cats to decompress the spinal cord, which resulted in a remission of clinical signs and no recurrence during 14 to 40 months of follow-up after surgery in all cases.

Spinal epidural empyema concurrent with sequestrum in a cat: a case report.

A 5-month-old intact female mixed cat presented with repetitive paraplegia and drainage of pus from the back despite continuous antibiotic medication. Neurologic examination was consistent with below T3-L3 myelopathy. Computed tomography and magnetic resonance imaging revealed a contrast-enhanced mass in the L1-3 spinal canal, and bone fragments in the T13 and L1 spinal canal. Spinal epidural empyema was suspected, and hemilaminectomy was performed for T12-L2 on the right side and T11-12 on the left side. Bone fragments were diagnosed as sequestrum infected with Bacteroides sp. The cat recovered enough to ambulate next day. One month after surgery, there was no deficit in neurological function. This is the first report of spinal epidural empyema concurrent with sequestrum in a cat.

[Kinetic and kinematic gait analysis of the back movement in chondrodystrophic breeds following hemilaminectomy in comparison to a healthy control population]. / Kinetische und Kinematische Gangbildanalyse der Rückenbewegung chondrodystropher Rassen nach Hemilaminektomie im Vergleich zu einer gesunden Population.

OBJECTIVE: To collect kinetic and kinematic data on the back movement in healthy dogs in comparison to chondrodystrophic dogs following hemilaminectomy while walking and trotting. MATERIAL AND METHODS: Gait analysis on the back movement was obtained from 19 healthy dogs and 21 chondrodystrophic dogs following hemilaminectomy procedure in consequence to disc herniation in the thoracic or lumbar region. RESULTS: In transverse and sagittal planes the group of surgically treated dogs showed a higher range of motion (ROM) throughout the spine while walking and trotting. The difference in back movement depended on the region of the hemilaminectomy (thoracic, thoracolumbar, or lumbar). Operated dogs showed a significantly higher weight distribution towards their front limbs. When comparing the weight distribution among the hind limbs, there was a decreased Peak Vertical Force (PVF) and Vertical Impulse (VI) on the side corresponding to the hemilaminectomy. CONCLUSIONS: Following hemilaminectomy, dogs displayed increased instability within their spine, which - depending on the region and side of the hemilaminectomy - affected the back movement in different ways. Weight bearing was generally shifted away from the hind limb of the affected side, and towards the front limbs. CLINICAL RELEVANCE: Even though hemilaminectomy has an effect on the back movement of dogs, it seems not to have relevant influence of quality of life.

Diagnosis and Treatment of a Spinal Intraosseous Keratinized Cyst of L1 in a Dog.

An 8 yr old female spayed golden retriever presented for a 3 wk history of progressive pelvic limb ataxia. MRI revealed a well-circumscribed T2-weighted hyperintense, T1-weighted poorly contrast-enhancing extradural mass to the right of the spinal cord at the level of L1 causing severe spinal cord compression. A right-sided hemilaminectomy was performed to remove the mass, and histopathology revealed an intraosseous keratinized cyst. A complete neurologic recovery was made within 2 wk following the surgery. This case illustrates a rare diagnosis and the first case report describing MRI findings and favorable clinical outcome after surgical management of a spinal intraosseous keratinized cyst.

A long survival case of spinal nephroblastoma in a dog.

Background: Dogs' nephroblastoma of the spinal cord is a rare neoplastic disease, with few reports of long-term survival after surgery. We experienced that surgical treatment with postoperative radiation therapy for spinal nephroblastoma in a dog resulted in the long-term survival of 11 years. Case Description: The patient presented to our veterinary hospital because of progressive hindlimb paralysis. Based on diagnostic imaging, she was diagnosed with a thoracolumbar spinal cord tumor and was treated with surgery. The gross tumor tissue was removed after laminectomy, followed by postoperative radiation therapy using orthovoltage equipment. The histopathological features of the surgical specimen were consistent with those of previously reported spinal nephroblastoma, although infrequent mitotic figures were observed. The dog recovered well after treatment and resumed her normal walking condition. No tumor recurrence was observed on periodic follow-up magnetic resonance imaging performed 10 and 21 months after surgery. Imaging evaluation for the gradual development of hindlimb weakness was performed 9 years after surgery; however, no recurrence of tumor tissue was observed, and spondylosis deformans, probably induced after laminectomy, were identified as a possible cause. The dog died of aspiration pneumonia 11 years after surgery, independent of spinal nephroblastoma. Conclusion: To date, no clinical cases of canine spinal cord primary nephroblastoma that survived for 11 years after surgery have been reported. This case strongly suggests that providing intensive treatment for canine spinal nephroblastoma is very important.

Association of hydromyelia and acute compressive myelopathy caused by intervertebral disc extrusion in dogs.

BACKGROUND: Hydromyelia is a common magnetic resonance imaging (MRI) finding associated with compressive myelopathy caused by intervertebral disc extrusion (IVDE). OBJECTIVES: To describe the MRI features of hydromyelia and explore its relationship to clinical history, neurological severity, and the duration of cord compression. ANIMALS: Ninety-one client-owned dogs with a focal compressive myelopathy secondary to thoracolumbar IVDE. METHODS: A retrospective observational study was conducted in which MRIs were blindly evaluated to grade and localize hydromyelia and measure the degree of spinal cord compression. Duration and severity of clinical signs were recorded. Differences between hydromyelia grades in these variables were statistically assessed using a Wilcoxon and Kruskal Wallis test. Receiver operator curve analysis was used to determine the sensitivity and specificity for duration of clinical signs to predict the presence of hydromyelia. RESULTS: Hydromyelia was identified at sites of IVDE in 84 of 91 dogs. An absence of hydromyelia was associated a with statistically longer duration of clinical signs (mean 73.1, IQR 76 days) when compared to cases with mild (mean 17.7, IQR 7.25 days, P = .006) or severe (mean 17.9, IQR 10.25 days, P = .006) hydromyelia. Duration of clinical signs <14 days was 78.6% sensitive and 85.7% specific for predicting the presence of hydromyelia. CONCLUSIONS AND CLINICAL IMPORTANCE: The MRI finding of hydromyelia might be a predictor of lesion chronicity in focal IVDE, helping to guide planning of hemilaminectomy surgery.

Uncommon Atlantoocciptal Localization of Tumoral Calcinosis in a Dog.

A 5-month-old male Rottweiler dog presented with an acute upper motor neuron tetraparesis. A computed tomography study of the cervical spine revealed amorphous mineralization of the soft tissues dorsal to the articular surface of the occipital bone and atlas. The calcification extended into the vertebral canal, causing significant dorsal compression of the spinal cord. Suboccipital craniectomy and partial dorsal atlas laminectomy were performed to remove the extradural calcification. Histopathology was compatible with tumoral calcinosis. Significant clinical improvement was noted in the immediate postoperative period, and there was complete recovery with no recurrence at the last clinical follow-up 15 months postoperatively. Suboccipital craniectomy and partial dorsal atlas laminectomy allowed successful surgical resection of a dorsal craniooccipital tumoral calcinosis in this dog. The decompression resulted in resolution of clinical signs and recurrence is unlikely since there is no underlying disease.