Summary This report describes a case of osteochondritis dissecans in a 3‐year‐old, female, neutered labrador retriever, where the osteochondritis dissecans lesion affected the seventh lumbar vertebra (L7), resulting in lumbosacral degenerative stenosis with marked asymmetric radiculitis of the L7 nerve root. Advanced imaging revealed an osteochondritis dissecans lesion of the right caudodorsal endplate of L7, alongside an elevated fibro‐osseous flap causing marked right‐sided foraminal stenosis and compressive radiculitis of the right L7 nerve root. Conservative treatment failure alongside a progressive radiculopathy resulted in surgical intervention. The surgery involved removal of the protrusive portion of the L7–S1 intervertebral disc, followed by distraction and fusion of the vertebrae in a flexed position, thus indirectly decompressing the right L7 nerve root. Long‐term follow‐up revealed dorsal columnar fusion and a positive clinical outcome with normal gait and exercise ability. At 15 months, a mild relapse of signs, including difficulty sitting, was reported. Follow‐up computed tomography revealed sacroiliitis, which was deemed to be an example of adjacent segment disease, with advanced imaging and the subsequent disease course not consistent with an infectious or other cause.

Far-lateral intervertebral disc extrusions (IVDE) represent an uncommon subset of intervertebral disc disease in dogs, in which disc material is herniated dorsolaterally or laterally to compress the exiting nerve root in an extraforaminal location. While minimally invasive spinal surgery techniques have been described in dogs, to the authors knowledge, full-endoscopic discectomy has not previously been reported for extraforaminal IVDE. This case report describes the clinical presentation, surgical technique, and short-term outcomes of extraforaminal endoscopic lumbar discectomy (EELD) in two dogs. Two middle-aged crossbreed dogs were presented with subacute onset of vocalization, pelvic limb lameness presumed to be a nerve root signature, and marked lumbar hyperaesthesia without other abnormalities on neurological examination. MRI or CT confirmed L5-6 extraforaminal disc extrusion with L5 spinal nerve root compression in both cases. Medical management failed to resolve clinical signs. Using a uniportal approach, a 6.3 mm diameter working-channel endoscope was fluoroscopically docked onto the transverse process of the vertebra caudal to the affected disc, creating a muscle-sparing lateral corridor. Extruded disc material was visualized, released from its fibrous capsule, and removed piecemeal without the need for osteotomy. Surgical times were 25 and 30 min. Post-operative CT confirmed effective decompression in both dogs. Post-operative recovery was rapid, with low pain scores and no requirement for opioid analgesia. Dogs were discharged within 24 h, and by 3 weeks both were free of lameness and spinal pain. At 12 weeks, caregiver-reported outcomes demonstrated sustained improvement, including a substantial reduction in Canine Brief Pain Inventory scores. EELD provided effective decompression through a minimally invasive corridor with excellent early outcomes. This first description in dogs supports further investigation of EELD as an alternative to conventional open surgical approaches for extraforaminal IVDE.

ObjectiveTo develop and report the accuracy and safety of a technique for percutaneous pedicle screw-rod fixation of the thoracolumbar and lumbosacral regions using fluoroscopic guidance in dog cadavers, comparing two levels of surgical experience.Study designCadaveric methods comparative study.AnimalsCadaveric vertebral columns of dogs (n = 3).MethodsPre-operative computed tomography (CT) scans facilitated in-silico surgical planning. Ideal implant insertion points and trajectory were recorded, and the image was subsequently reconstructed to mimic the appearance of intra-operative fluoroscopy. After surgical preparation from T8 to S2, the study was divided in two parts: part one to evaluate safety and accuracy of percutaneous “end-on” fluoroscopic drill hole position technique (EOFG); and part two to determinate the feasibility of thoracolumbar (T13-L1) and lumbosacral (L7-S1) percutaneous cannulated pedicle screw and rod fixation (PC-PSRF). The procedures were performed by one of two experienced ECVN diplomates, and one ECVN neurology resident (inexperienced in spinal fixation surgery). Following post-operative CT imaging, drill-hole safety was established using a modified Zdichavsky classification and optimal placement was compared between surgeons. Drill-hole accuracy was calculated based on the deviation from planned angle and bone purchase, between the two levels of surgeon experience. Data sets were analysed at both univariable and multivariable levels with logistic regression analysis.ResultsNo unsafe holes (0/34) were drilled by experienced surgeons, whereas the inexperienced surgeon drilled 4/34 (11.8%) unsafe holes. Optimal drill-hole placement was significantly associated with surgeon experience (p < 0.001, OR = 9.66), whereas cadaver number and spinal region did not reach significance. Drill-hole angle and bone depth deviations were significantly different between experienced and inexperienced surgeons (p = 0.04 and p < 0.001, respectively). Angle deviations were not significantly different between experience levels by region, whereas mean bone purchase deviations were significantly lower for experienced surgeons in the thoracic region (p = 0.002), but differences were not significant in the lumbar and sacral regions. The mean time taken to drill the hole was significantly longer for the inexperienced surgeon (p < 0.001). PC-PSRF using EOFG was successfully demonstrated at T13-L1 and L7-S1.ConclusionThe technique was feasible and allowed for percutaneous fixation of the thoracolumbar and lumbosacral segments. Previous experience in open instrumented spinal surgery is beneficial for safe and accurate application.Clinical significanceThe PC-PSRF technique using EOFG guidance warrants future clinical studies to investigation a potential role in reducing pain, hospitalisation length, muscle injury and need for surgical revision.

IntroductionDegenerative lumbosacral stenosis (DLSS) is a common cause of pain in dogs, with lumbosacral foraminal stenosis (LSFS) frequently contributing to clinical signs through spinal nerve root compression. Conventional surgical approaches for foraminal decompression can be invasive and technically challenging. This study aimed to develop a lateral full-endoscopic lumbosacral foraminotomy (LELF) technique and evaluate its feasibility, safety, and effectiveness in dogs.MethodsLELF was first established in two large-breed dog cadavers, followed by clinical assessment in three dogs diagnosed with LSFS with cross-sectional imaging. Pre- and post-operative assessments included standardized DLSS scoring, owner-reported pain inventory (CBPI), and CT-based neuroforaminal volume measurements. Intra-operative parameters including incision length, surgical time, and visualization quality were recorded.ResultsLELF was successfully performed on nine foramina (four cadaveric, five clinical) without conversion to open surgery. Incision length was < 10 mm, median surgical time was 95 min per foramen. All key anatomical landmarks were visualized, and no iatrogenic nerve root injuries occurred. Post-operative CT demonstrated significant enlargement of the lumbosacral foramina (median pre-operative volume: 315.2 mm3; post-operative: 605.6 mm3; P = 0.004). Clinical outcomes improved markedly at 6-month follow-up, with DLSS and CBPI scores indicating substantial pain reduction and restoration of excellent quality of life.ConclusionLELF is a feasible and minimally invasive technique for LSFS in dogs, achieving effective foraminal decompression and favorable medium-term clinical outcomes. Further studies are warranted to assess long-term efficacy and to compare LELF with open and bi-portal endoscopic approaches.

ObjectiveThis study aimed to evaluate the medium-term outcome following spinal cord decompression and instrumented fixation of single-level congenital thoracolumbar vertebral malformations, characterized by combined failures of segmentation and formation, causing thoracolumbar myelopathy in three large-breed dogs.Study designThis was a retrospective clinical study.AnimalsThe animals involved in the study were three large-breed dogs.MethodsElectronic patient records were retrospectively reviewed for adult large-breed dogs (>1 year) (>25 kg) with thoracolumbar myelopathy and a radiologic diagnosis of spinal cord compression associated with thoracolumbar vertebral malformation. The examination, diagnostic imaging, surgical management, and outcomes are described. The medium-term outcome was determined based on the neurological examination and follow-up imaging studies conducted up to 12 months post-operation.ResultsThree large-breed dogs were identified, presenting with progressive, non-painful T3–L3 spinal cord segment disease. Diagnosis was made using MRI and CT, which revealed single-level complex congenital vertebral malformation with combined failures of segmentation and formation in the T8–L1 region. Surgical management consisted of ventral cord decompression by bilateral mini-hemilaminectomy and partial corpectomy and vertebral fixation. Temporary postoperative neurological deterioration was observed in two cases. Follow-up was conducted at 6 weeks (examination) and 3 (examination), 6, and 12 months (examination and CT) postoperatively, and improved neurological function was confirmed, with all cases being ambulatory with persistent, mild paraparesis.ConclusionThis retrospective study demonstrates the successful medium-term outcome following surgical management of complex thoracolumbar vertebral malformations in large-breed dogs.

Pug dogs are predisposed to thoracolumbar myelopathy associated with vertebral articular process dysplasia, suggesting a biomechanical etiology. While surgery is commonly pursued, long-term outcomes remain poorly defined. This retrospective descriptive case series reports on seven Pug dogs that underwent surgical treatment for thoracolumbar myelopathy and were followed up for at least 7 years postoperatively. All dogs were part of a previously published cohort treated at the same institution and were included in this follow-up based on caregiver consent. Dogs were classified into three groups—intervertebral disc protrusion (IVDP), spinal arachnoid diverticulum (SAD), or pia-arachnoid fibrosis (PAF)—based on imaging and intraoperative findings. All dogs underwent vertebral stabilization, with decompression performed in the IVDP and SAD groups. Follow-up data were collected via caregiver questionnaire and review of clinical records. Temporary clinical improvement or stabilization was achieved in five of seven Pug dogs (71%), particularly in the IVDP and SAD groups. Recurrence of neurological signs was noted in four of these five dogs (80%), with a median time to recurrence of 8.9 months. The median survival time following surgery across all seven dogs was 3.2 years. Dogs with PAF demonstrated the poorest outcomes. Favorable outcomes were associated with younger age, shorter lesion extension, and milder T2-weighted hyperintensity. Urinary and/or fecal incontinence and recurrent urinary tract infections were common comorbidities. Surgery was considered beneficial by caregivers in four (57%) of seven cases. In conclusion, vertebral stabilization with decompression may provide temporary clinical benefit in Pug dogs with thoracolumbar myelopathy. However, recurrence is common, and PAF may predict a less favorable prognosis. Larger-scale studies are warranted to explore potential associations between intrathecal inflammation, the necrotizing meningoencephalitis (NME) risk haplotype, and response to adjunctive therapies such as corticosteroids or cerebrospinal fluid diversion techniques. Urinary incontinence should be closely monitored to minimize complications.

Objective To determine whether dogs with magnetic resonance imaging (MRI)-determined intracranial space occupying lesions (MRI-iSOLs) or intracranial hypertension (MRI-ICH) had greater sedation scores and quicker onset of recumbency following premedication with intravenous (IV) butorphanol in comparison with dogs which had normal MRI findings. Study design Prospective, observational study. Animals A total of 53 dogs presenting for brain MRI were included. Methods Each dog was sedated with 0.2 mg kge1 butorphanol IV, and the quality of sedation and the onset of recumbency were scored before drug administration and every 5 minutes after IV butorphanol administration for 15 minutes using a modified sedation scale. The maximum sedation score was 18, and onset of recumbency was recorded when a dog lay down without the ability to stand. Each MRI was assessed for the presence or absence of MRI-iSOL and MRI-ICH using T2-weighted sequences. Data were analysed using the Wilcoxon rank sum test or the chi-square test. Results Dogs with MRI-iSOL had significantly higher median sedation scores than dogs without MRI-iSOL (12 versus 5, respectively) 15 minutes after butorphanol administration (T15, p < 0.01). A greater number of dogs with MRI-ICH achieved recumbency (n = 9/10; 90%) than those without MRI-ICH (n = 20/43; 46.5%; p = 0.01). Conclusions and clinical relevance When intracranial disease is suspected, the administration of butorphanol as a premedicant for anaesthesia could be used to predict the presence of MRI-iSOL and MRI-ICH. If a dog becomes recumbent or has a sedation score > 10 within 15 minutes of butorphanol administration, the animal should be treated with an anaesthesia protocol adapted to the presence of ICH.

Abstract Background Traditionally, 6‐month courses of prednisolone are used to treat steroid‐responsive meningitis‐arteritis (SRMA), but this medication is associated with adverse effects that can lead to poor quality of life. Hypothesis/Objectives Resolution of clinical signs and rate of relapse of SRMA would not be significantly different between a 6‐month prednisolone protocol and a 6‐week protocol. Animals Forty‐four hospital cases from multiple referral centers in the United Kingdom (2015‐2019). Twenty of 44 were treated with the 6‐month protocol and 24/44 with the 6‐week protocol. Methods Prospective, randomized trial with 12‐month follow‐up. The same prednisolone protocol reinitiated in the event of relapse. Analysis of relapses with binary logistic and Poisson regression modeling. Results All cases responded to their treatment protocol. Relapses occurred in 6/20 (30%) of the 6‐month protocol and 9/24 (38%) of the 6‐week protocol. There was no statistical difference in the incidence risk of at least 1 relapse between the 2 groups (odds ratio = 1.40; 95% confidence interval [CI], 0.40‐4.96, P = 0.60). Among the 15 dogs that relapsed, 10/15 (67%) relapsed once, 3/15 (20%) relapsed twice, and 2/15 (13%) relapsed 3 times. No statistical difference was detected in the incidence rate ratio (IRR) of total relapse events between the 2 groups (IRR = 1.46; 95% CI, 0.61‐3.48; P = 0.40). Conclusions and Clinical Importance “Short” 6‐week prednisolone protocols could be used to treat SRMA, thereby presumably reducing the duration and severity of prednisolone's adverse effects.

ObjectiveTo develop and evaluate the safety and accuracy of an open, end-on fluoroscopic guided (EOFG) drill hole position technique in canine cadaveric spinal surgery, in comparison to a traditional free-hand (FH) drilling technique.Study designCadaveric comparison study.AnimalsCanine cadaveric vertebral columns (n = 4).MethodsComputed tomography (CT) scans were performed for in-silico planning. Ideal implant purchase depth and angulations were determined from previously published data. Plans for end-on fluoroscopic guided drill holes included angled reconstructions in thick slab mode to mimic fluoroscopic images. Following surgical preparation of T8 to S2, holes were drilled by one of two experienced surgeons randomized evenly by operated side, surgeon, and technique. C-arm fluoroscopy was utilized for the end-on technique. CT was repeated after the procedures. Safety was determined categorically using a modified Zdichavsky classification and “optimal” placement was compared between techniques. Continuous data for drill-hole accuracy was calculated as angle and depth deviations from the planned trajectories. Data sets were analyzed at both univariable and multivariable levels with logistic regression analysis.ResultsDrill hole safety was categorized as optimal (modified Zdichavsky classification 1) in 51/60 (85%) of drill holes using EOFG and 33/60 (55%) using FH (P < 0.001) techniques. There were no “unsafe” holes (modified Zdichavsky classification 3a). Optimal drill hole placement was significantly associated with the EOFG technique and use of the largest cadaver, and was significantly less likely within the thoracic region. Mean angle and depth deviations were significantly lower with the EOFG technique. Angle deviations were significantly lower for EOFG in the lumbar region, whereas bone purchase deviations were significantly lower for EOFG in both the thoracic and lumbar regions. The mean time taken to drill the hole was significantly longer for the EOFG technique.ConclusionOptimal drill hole placement was significantly more likely with the EOFG technique and improved the accuracy of bone purchase in the thoracic region.Clinical significanceThe EOFG technique shows promise for translation into a clinically setting, potentially improving implant purchase and therefore stabilizing construct strength, whilst potentially reducing the likelihood of neurovascular injury and need for surgical revision.

This report describes a chronic case of discospondylitis and sublumbar abscessation managed with a combination of omentalisation and vertebral stabilisation. Although there are previous reports of omentalisation in patients presenting with sublumbar abscesses, there are no documented cases of these surgeries being combined with stabilisation of a vertebral body fracture secondary to discospondylitis. This case specifically discusses an initial conservative approach and subsequent surgical intervention. A 5-year-old, female, neutered, cocker spaniel presented with a 2-month history of lethargy, non-localised pain, reluctance to move and pyrexia. Diagnostic investigations revealed a fracture of the third lumbar vertebrae, associated discospondylitis and sublumbar abscessation due to suspected foreign material. Conservative management with rest and antimicrobial therapy was initiated; however, after worsening of clinical signs, surgery was subsequently carried out. We report post-operative follow-up of 4 years, which revealed an overall positive outcome, with no long-term recurrence of clinical signs or adverse effects.

The study described the clinical and imaging findings, treatment and outcome for a British bulldog with cranial thoracic vertebral canal stenosis and thoracolumbar kyphoscoliosis. Data on clinical presentation, diagnostic imaging, surgical procedure, complications and outcome were evaluated. Multiple thoracic vertebral body and dorsal arch malformations were detected by computed tomography and magnetic resonance imaging, resulting in spinal cord compression due to vertebral canal stenosis at T5-T6 and T9-T10, as well as kyphoscoliosis. Surgical vertebral stabilisation between T2 and T10 was performed by using a novel design of unilateral three-dimensional printed patient-specific drill guides, to preserve the dorsal spinous processes. Neurological signs had completely resolved 2 months after surgery. Follow-up examination and computed tomography scan 15 months postoperatively revealed normal neurological status, implant stability and no progression of kyphoscoliosis. This novel design of unilateral three-dimensional printed patient-specific drill guides allowed dorsal thoracic vertebral stabilisation without resection of dorsal spinous processes and multiple-level stabilisation.

IntroductionA retrospective study to compare the classification, as normal, hypoplastic or aplastic, of thoracic (T10-T13) caudal articular process (CAP) morphology in Pug dogs with a thoracolumbar myelopathy as normal, hypoplastic or aplastic, between T2 weighted Turbo Spin Echo (T2W-TSE), in sagittal and transverse planes, and Volumetric Interpolated Breath-hold Examination (VIBE) Magnetic Resonance Imaging (MRI) sequences, in comparison to Computed Tomography (CT). We hypothesized a stronger agreement for VIBE in comparison to T2W-TSE.ResultsDiagnostic accuracy of T2W-TSE was inferior to VIBE for aplastic (60%, 95% CI 0.561–0.639 vs. 78%, 95%CI 0.744–0.815) hypoplastic (44%, 95%CI 0.427–0.452 vs. 62.5%, 95%CI 0.595–0.655) and normal CAP (70%, 95%CI 0.655–0.744 vs. 87%, 95%CI 0.848–0.892). Superior accuracy of classification using VIBE vs. T2W-TSE sequences using the McNemar Chi squared test was significant for aplastic (p = 0.0002) and normal CAP (p = 0.004). VIBE sequences had a sensitivity of 96% and specificity of 75% to detect CAP abnormality and with T2W-TSE imaging sensitivity 81% and specificity of 75%.DiscussionThree-dimensionally reconstructable VIBE sequences were significantly more accurate than traditional T2W-TSE MRI sequences in classifying CAP morphology, which should reduce the need for CT for pre-operative assessment.

Objective:To report the medium and long-term outcome of nine dogs with disk-associated cervical spondylomyelopathy (DA-CSM), treated by instrumented interbody fusion using patient specific end-plate conforming device that features a micro-porous structure to facilitate bone in-growth.Study design:A retrospective clinical study.Animals:Nine medium and large breed dogs.Methods:Medical records at two institutions were reviewed between January 2020 and 2023. Following magnetic resonance imaging (MRI) diagnosis of DA-CSM, pre-operative computed tomography (CT) scans were exported to computer software for in-silico surgical planning. Interbody devices were 3D-manufactured by selecting laser melting in titanium alloy. These were surgically implanted at 13 segments alongside mono-or bi-cortical vertebral stabilization systems. Follow-up included neurologic scoring and CT scans post-operative, at medium-term follow up and at long-term follow-up where possible. Interbody fusion and implant subsidence were evaluated from follow-up CT scans.Results:Nine dogs were diagnosed with DA-CSM between C5-C7 at a total of 13 operated segments. Medium-term follow up was obtained between 2 and 8 months post-operative (3.00 ± 1.82 months). Neurologic scoring improved (p = 0.009) in eight of nine dogs. Distraction was significant (p < 0.001) at all segments. Fusion was evident at 12/13 segments. Subsidence was evident at 3/13 operated segments but was only considered clinically relevant in one dog that did not improve; as clinical signs were mild, revision surgery was not recommended. Long-term follow up was obtained between 9 and 33 months (14.23 ± 8.24 months); improvement was sustained in 8 dogs. The dog that suffered worsened thoracic limb paresis at medium-term follow up was also diagnosed with immune-mediated polyarthropathy (IMPA) and was euthanased 9 months post-operative due to unacceptable side-effects of corticosteroid therapy.Conclusion:End-plate conforming interbody devices with a micro-porous structure were designed, manufactured, and successfully implanted in dog with DA-CSM. This resulted in CT-determined fusion with minimal subsidence in the majority of operated segments.Clinical significance:The technique described can be used to distract and fuse cervical vertebrae in dogs with DA-CSM, with favorable medium-and long-term outcomes.

Abstract Vertebral malformations in dogs: Clinical signs and diagnosis Describe the characteristic clinical signs associated with vertebral malformations in brachycephalic dogs and common breeds affected Recognise the typical diagnostic imaging findings of common vertebral malformations in dogs and how to determine if they are clinically relevant Discuss the possibility of vertebral malformations being associated with other vertebral column disease (e.g. intervertebral disc disease, kyphosis) Vertebral malformations in dogs: Can anything be done? List the treatment options available (medical and surgical) for the management of common vertebral malformations in dogs Describe some of the common surgical options for management of vertebral malformations and possible future directions Recognise possible complications of surgical management and requirements for post-operative care

Brain tumours in dogs: is chemotherapy and radiation the answer? Describe the common brain tumours for which chemotherapy or radiation therapy is a key treatment option Briefly compare the outcomes associated with different brain tumours treated with chemotherapy or radiation therapy Discuss the advantages and disadvantages of chemotherapy and radiation therapy for the brain - including complications Brain tumours in dogs: is surgery the answer? Describe the common brain tumours for which surgical management is a key treatment option Briefly compare the outcomes associated with different brain tumours treated surgically Discuss the advantages and disadvantages of surgical management - including complications

Spinal tumours in dogs: is chemotherapy and radiation the answer? Describe the common spinal cord and vertebral tumours for which chemotherapy or radiation therapy is a key treatment option Briefly compare the outcomes associated with different spinal cord and vertebral tumours treated with chemotherapy or radiation therapy Discuss the advantages and disadvantages of chemotherapy and radiation therapy for the spinal cord and vertebral column - including complications Spinal tumours in dogs: is surgery the answer? Describe the common spinal cord and vertebral tumours for which surgical management is a key treatment option Briefly compare the outcomes associated with different spinal cord and vertebral tumours treated surgically Discuss the advantages and disadvantages of surgical management - including complications

Case summary A 10-year-old male neutered Russian Blue cat was presented with a 2-month history of progressive non-ambulatory paraparesis. Spinal MRI revealed a well-demarcated, compressive intradural extramedullary mass at the level of T1 vertebra. The mass had subtle hyperintensity on T2-weighted images, was isointense on T1-weighted images and had diffuse, marked enhancement following gadolinium administration. Neuroaxis MRI, including limited brain sequences, excluded other visible lesions. Thoracic and abdominal radiographs were unremarkable. The mass was resected via a dorsal C7–T2 laminectomy and durotomy. Histopathology revealed a neoplasm composed of columnar-to-polygonal cells forming bilayered palisading patterns with a few apical cilia. Three mitoses were noted in 10 high-power fields. This was consistent with an epithelial neoplasm and initially a metastatic adenocarcinoma was considered most likely. Full-body CT with contrast and including the brain found rhinitis but did not identify any additional neoplastic foci. Biopsies of the nasal cavity and fine-needle aspiration of the spleen and liver were unremarkable. On immunohistochemical evaluation, pan-cytokeratin and E-cadherin immunolabelling was observed; however, synaptophysin, thyroglobulin, chromogranin A and glial fibrillary acidic protein was not detected. This, along with the histological morphology and absence of a primary tumour, was compatible with an ectopic choroid plexus neoplasm. Follow-up performed at 3, 14 and 24 months postoperatively revealed neurological improvement without recurrence. Relevance and novel information We describe the presentation, histopathological and immunohistochemical features and outcome of a case of a rare ectopic choroid plexus neoplasm in the spinal cord of a cat.

Case series summary We describe here the surgical management of two pure breed cats with traumatic atlantoaxial subluxation. One cat was ambulatory tetraparetic on presentation and the second was tetraplegic, both with cervical spinal pain and acute onset of paresis with subsequent deterioration. MRI was performed in both cases, demonstrating spinal cord injury. Flexed lateral cervical radiographs were needed to confirm atlantoaxial subluxation in one case. CT was performed for surgical planning and surgical stabilisation was achieved with threaded pins and polymethyl methacrylate (PMMA) cement; odontoidectomy was required in one case. Both cats showed improvement postoperatively, with no complications or deterioration seen. Following surgery, one cat made a complete recovery; however, the second cat retained significant deficits. Relevance and novel information We present the first report of surgically managed atlantoaxial subluxation of traumatic aetiology in cats, and report its occurrence in two novel breeds for this disease, Ragdoll and Persian. One case required odontoidectomy due to previous fracture and malunion of the odontoid process of the axis; both cases underwent surgical stabilisation of the atlantoaxial joint utilising multiple threaded pins and PMMA cement without transarticular implants – a technique that has not been previously reported in cats.

We describe a 3-year-old English Springer Spaniel presented with peracute and traumatic onset of cervical spinal cord signs of non-ambulatory tetraparesis and bilateral Horner's syndrome. MRI and CT revealed aplasia of the odontoid process, dramatic dorsal displacement of the axis and marked compression of the spinal cord with changes consistent with oedema and inflammation. Surgical reduction of the vertebrae and atlantoaxial arthrodesis was successful, with recovery of ambulation over 6 weeks. A follow-up CT 6 weeks later confirmed stability of the implants. The dog is clinically stable 19 months on. Traumatic atlantoaxial subluxation associated with congenital dysplasia of the odontoid process is rarely reported in medium breed dogs.

Case series summary The aim of this case series was to describe the clinical presentation, imaging findings and histopathology of three cats with limited dorsal myeloschisis (LDM). The history, examination and MRI sequences were reviewed in three cases presented to a single referral hospital. The surgery report and histopathology were described in two cases. All cats were young (10 weeks old, 5 months old, 4 years old), presenting with varying degrees of progressive paraparesis. All had a midline skin defect overlying the spinal column that was either sunken or saccular, containing fluid thought to be cerebrospinal fluid. MRI sequences demonstrated tissue extending from the dura through an overlying bifid spinous process and attached to the dermis, with associated spinal cord tethering, atrophy and syringomyelia. Lesions were located at L2–L3, T8–T9 and L4. Histopathology described a fibroneural stalk with a glio-ependymal lining, surrounded by glial nests and nerve fibres. The youngest and most severely affected was euthanased, while the other two underwent surgery. Both regained independent ambulation with persistent paraparesis; however, one required ongoing management of urinary incontinence. Relevance and novel information LDM is a primary neural tube defect that may result in neurological deficits, including bladder dysfunction, and is characterised by a fibroneural stalk between the dermis and the spinal cord. Distinct MRI features, such as a visible intrathecal tract, dorsally tethered cord and syringomyelia, help distinguish this condition from the clinically similar dermoid sinus. The presence of progressive neurological signs, with a palpable midline defect overlying the affected spinal cord segment, may raise suspicion for this clinical entity in veterinary patients.