Microendoscopic Dorsal Laminectomy for Multi-Level Cervical Intervertebral Disc Protrusions in Dogs.

The objective of this study was to evaluate the feasibility and clinical outcomes of microendoscopic dorsal laminectomy for multi-level cervical intervertebral disc protrusions in dogs. Eight client-owned dogs diagnosed with multi-level cervical intervertebral disc protrusions using computed tomography (CT) and magnetic resonance imaging (MRI) were included in this retrospective case series. Microendoscopic dorsal laminectomies (MEL) were performed with an integrated endoscopic system to the cranial and caudal vertebrae of the affected intervertebral joints. Pre- and post-operative neurological status, operation time, intra-operative complications, and postoperative complications were reviewed. Post-operative CT images were obtained to measure the dimensions of laminectomy and compared to those of planned laminectomy. Full endoscopic procedures were feasible in 7 dogs (87.5%) and the laminectomy dimensions were in agreement with pre-operative planning. In all dogs, major intra- and postoperative complications did not occur. Conversion to open surgery was required in one case. Short-term postoperative clinical deterioration was found in two dogs. Long-term clinical outcomes were good and comparable to those reported in previous studies of open dorsal laminectomies. MEL is a promising minimally invasive approach to multi-level cervical dorsal laminectomy for intervertebral disc protrusions. This technique may improve postoperative discomfort compared to the open approach. Further studies are needed to directly compare outcomes between these two approaches.

Case Report: Spinal Stabilization Surgery Using a Novel Custom-Made Titanium Fixation System for the Spinal Instability Caused by Vertebral Malformation in a Dog.

A 2-year-old Maltese was presented with wobbly gait of the pelvic limbs. Based on imaging examinations, a diagnosis of congenital malformation at T5-T8 and severe kyphosis causing spinal cord compression at T6-T7 was made. Dorsal laminectomy and stabilization of T6 and T7 vertebrae were performed. As the size of the vertebrae was small and they were severely deformed, novel custom-made titanium implants were used for spinal stabilization. Clinical signs were resolved 2 weeks after surgery. Although radiographic examination 373 days after surgery showed slight loosening of implants, post-operative course remained uneventful. This report describes the use of novel custom-made titanium implants for spinal fixation surgery in a dog.

Minimally invasive spinal surgery in a young cat with vertebral hypertrophy.

CASE SUMMARY: A 2-year-old neutered female Scottish Fold cat was presented with an 8-week history of progressive back pain, paraparesis and decrease of postural reactions in both pelvic limbs. MRI showed spinal cord compression from both ventral sides, which originated from the T4 vertebral body and pedicle. The lesion compressing the spinal cord had a bone-like density on CT, and endoscopic surgery was performed to excise it. Histopathological examination of the resected tissue showed no evidence of malignancy and the lesion was diagnosed as vertebral hypertrophy. After surgery, the neurological status of the cat gradually improved. The cat was ambulant at the follow-up evaluation 2 weeks after surgery. Six months later, hindlimb paresis had improved considerably, and no recurrence was observed on CT. RELEVANCE AND NOVEL INFORMATION: This is the first description of thoracic vertebral canal stenosis due to hypertrophy of a single vertebra in a young cat. Excision of the hypertrophic vertebra by endoscopic surgery is less invasive than open surgery and may give a good prognosis.

Microendoscopic Mini-Hemilaminectomy and Discectomy in Acute Thoracolumbar Disc Extrusion Dogs: A Pilot Study.

The objective of this study was to evaluate the clinical outcomes and complications of a microendoscopic laminectomy and discectomy (MED) for acute thoracolumbar intervertebral disc extrusions in dogs. Eleven client-owned dogs with acute thoracolumbar intervertebral disc extrusions were included in this retrospective case-series. Dogs were diagnosed with acute thoracolumbar intervertebral disc extrusions using computed tomography (CT) and magnetic resonance imaging (MRI). MED was performed with an integrated endoscopic system to the affected intervertebral disc. Surgery time, intra-operative complications, causes of conversion to microscopic surgery if necessary, post-operative complications, and neurological status on presentation at discharge, as well as any further evaluations in hospital, and long-term concerns via owner contact, were recorded. Post-operative CT images were obtained to compare the extent of laminectomy performed to the planned region of laminectomy. The fully endoscopic procedure was completed in eight dogs without major complications. Three cases were converted to an open surgery due to difficulty removing extruded disc material and controlling hemorrhage. The clinical outcome was good in all cases and equivalent to previously reported prognoses after open surgery. MED is an effective and safe alternative to conventional open procedures in dogs with acute thoracolumbar intervertebral disc extrusion.

Changes of Dorsal Root Ganglion Volume in Dogs with Clinical Signs of Degenerative Myelopathy Detected by Water-Excitation Magnetic Resonance Imaging.

Canine degenerative myelopathy (DM) is a progressive and fatal neurodegenerative disease. However, a definitive diagnosis of DM can only be achieved by postmortem histopathological examination of the spinal cord. The purpose of this study was to investigate whether the volumetry of DRG using the ability of water-excitation magnetic resonance imaging (MRI) to visualize the DRG in dogs has premortem diagnostic value for DM. Eight dogs with DM, twenty-four dogs with intervertebral disc herniation (IVDH), and eight control dogs were scanned using a 3.0-tesla MRI system, and water-excitation images were obtained to visualize and measure the volume of DRG, normalized by body surface area. The normalized mean DRG volume between each spinal cord segment and mean volume of all DRG between T8 and L2 in the DM group was significantly lower than that in the control and the IVDH groups (P = 0.011, P = 0.002, respectively). There were no correlations within the normalized mean DRG volume between DM stage 1 and stage 4 (rs = 0.312, P = 0.128, respectively). In conclusion, DRG volumetry by the water-excitation MRI provides a non-invasive and quantitative assessment of neurodegeneration in DRG and may have diagnostic potential for DM.

Case Report: Surgical Treatment for Intranasal Meningoencephalocele in a Cat.

A 4-month-old cat with epileptic seizures and nasal discharge was presented, and diagnosed with intranasal meningoencephalocele based on the clinical symptoms and findings of CT and MRI. As liquorrhea was suspected, the meningoencephalocele was surgically excised and the postoperative course was favorable. For cribriform plate reconstruction, the autologous tunica vaginalis was used. Rhinorrhea of the cerebrospinal fluid and seizures disappeared after surgery. On CT and MRI at 7 months after surgery, septum formation between the cranial and nasal cavities was confirmed. Currently, no seizures have occurred even though no oral antiepileptic agent was administered. There are few reports of surgical treatment for meningoencephalitis, and there are no reports of reconstruction of the cribriform plate using tunica vaginalis, so we reported the details.

Case Report: Transoral Penetrating Medullocervical Injury by a Chopstick in Three Cats.

This case series describes transoral penetrating or contusive medullocervical injury by a wooden chopstick in three young cats presenting with acute tetraparesis. CT revealed that remnant fragments of a wooden chopstick penetrated the atlantooccipital space in cases 1 and 2. The remnant fragments were visualized clearly on CT under the bone window setting. MRI revealed a hyper-intense lesion in the spinal cord parenchyma at the level of C1 on T2-weighted images in case 3. Tetraparesis improved after surgical removal of the remnant fragment in case 2 and with supportive care in case 3.

Accuracy and Efficacy of a Patient-Specific Drill Guide Template System for Lumbosacral Junction Fixation in Medium and Small Dogs: Cadaveric Study and Clinical Cases.

Objectives: To develop drill guide templates as an intraoperative guide, and to evaluate the accuracy and safety of screw placement in the lumbosacral junction. Samples: Canine cadaveric specimens of the lumbosacral junction (n = 6), and clinical cases of lumbosacral instability (n = 3). Procedures: Computed tomography data of the lumbosacral region of cadaveric specimens and clinical cases were obtained. The optimum screw trajectories were determined and drill guide templates were fabricated using a three-dimensional printing system. Drill holes were made using the templates in cadaveric specimens and clinical cases, and lumbosacral fixation was performed in clinical cases. Computed tomography images were obtained to compare the planned and postoperative drill hole trajectories, and the accuracy and safety of drilling and screw placement in the lumbosacral junction were evaluated. Results: Thirty-six drill holes were made in cadaveric specimens. The overall mean drill hole deviation was 2.05 ± 1.32 mm. A total of 12 screws were placed in the lumbosacral junctions of three clinical cases. The overall mean drill hole deviation was 2.43 ± 1.09 mm. Clinical signs improved within 2 weeks in the clinical cases. All drill holes were completely located within the bone in cadaveric specimens and clinical cases. Conclusion and Clinical Relevance: The surgical procedures using the drill guide templates were performed safely with good clinical outcomes. The drill guide template system provided useful surgical guidance to safely and precisely perform screw placement for lumbosacral fixation surgery in small dogs.