Prevalence, clinical presentation and MRI of intervertebral disc herniations in cats

Retrospective study of partial lateral corpectomy to treat thoracic and lumbar intervertebral disc herniation in 12 cats

OBJECTIVES

The aim of this study was to describe the safety and effectiveness of thoracic or lumbar partial lateral corpectomy (PLC) in cats with spinal cord compression due to intervertebral disc herniation (IVH).

METHODS

A retrospective study was conducted of 12 client-owned cats from two academic and one private referral veterinary centres. Cross-sectional imaging was available in 12 cats for evaluation of disc herniation. Nine cats had postoperative imaging for evaluation of slot creation and decompression. Neurological examination was performed for assessment of pre- and postoperative status. Complications were evaluated.

RESULTS

Seven cats had severe (>50%), four moderate (>20 to <50%) and one mild (<20%) spinal cord compression on cross-sectional imaging. IVH occurred at Th12-13 in five cases, at L1-2 in two cases and at Th3-4, Th13-L1, L4-5 and L5-6 in one case each. After PLC, two cats had insufficient decompression (>20% remaining spinal cord compression), five had good decompression (<20% remaining spinal cord compression) and complete decompression (normal shape of the spinal cord) was achieved in two cats. Outcomes included five cats with an excellent result, three with significant improvement, one with mild improvement and three cats that died intra- or postoperatively due to extensive intraoperative bleeding. One cat was euthanased as a result of neurological deterioration 5 months postoperatively. The median follow-up period was 13.2 months (range 0 days to 84 months).

CONCLUSIONS AND RELEVANCE

PLC in cats offers a potential treatment option for IVH to decompress the spinal cord. Fatal haemorrhage associated with this surgery is a significant risk, as occurred in 25% of the cats in this study. Surgeons should especially be aware of the potential for intraoperative haemorrhage and the need for sufficient slot creation to achieve sufficient spinal cord decompression and avoid complications.

Evaluation of Radiological and Anatomical Features of Cervical Vertebrae in Adult Persian Cat

BACKGROUND

Radiographic studies of Persian cat's cervical vertebrae can provide us with valuable information used in identifying its anatomical features, investigating various species of Persian cats and evaluating their cervical pathologies.

OBJECTIVES

The present study aimed to investigate the anatomical and radiological features of cervical vertebrae in Persian cats to create a comprehensive and accurate reference for the normal range of cervical bones and joints that can be used for clinical decision-making and interpretation of radiographic findings in these cats.

METHODS

The present descriptive-cross-sectional study included 10 adult Persian cats, including 5 males and 5 females. All cats underwent radiography in the dorsoventral, ventrodorsal, left lateral and right lateral recumbency. Then, anatomical investigations were performed.

RESULTS

According to our findings, Persian cats were different from other cat species in some cervical vertebral characteristics, which can be suggested as comparative anatomy in these species. The most important differences were as follows: the C3 and C7 had the lowest and highest spinous process height (SPH), respectively. The atlas had the highest transverse process width (TPW), which was significantly different with other cervical vertebrae (p ≤ 0.05). Moreover, the cervical vertebrae were not significantly different in vertical diameter of cranial vertebral foramen (VDCrVF) and transverse diameter of cranial vertebral foramen (TDCrVF) (p ≤ 0.05). The caudal surface of the atlantic vertebral arch had two dorsal and ventral tubercles. Also, the ventral crest of the axis was quite indistinct in the cranial part while becoming prominent in the caudal part. The C3 spinous process was a wide, small tubercle, while the C7 spinous process was extended vertically. Finally, the C6 transverse processes had a large ventrocranial tubercle forming a sagittal plate with cranial and caudal parts separated by a notch.

CONCLUSION

The accurate and comprehensive standard ranges obtained from the present study can be used for the interpretation of imaging results, clinical decision-making, and finding the normal and abnormal sizes of the cervical vertebrae and their processes in Persian cats.

Cervical Disc Extrusion with Dorsal Migration in a Pet Rabbit

An 8-year-old rabbit presented with a 5-day history of acute difficulty in walking. Neurological examination revealed tetraparesis, proprioceptive deficits in both pelvic limbs and the right thoracic limb, decreased withdrawal reflex on the right thoracic limb and hyperreflexia in the pelvic limbs. A cervico-thoracic (C6-T2) localization was suspected. Computer tomography (CT) and magnetic resonance imaging (MRI) scans were performed, revealing a right dorsolateral extradural lesion at the C6-C7 intervertebral disc space. Additionally, meningeal and paravertebral contrast enhancement was observed on MRI, while periosteal reaction was evident at the right C6-C7 facet joint on CT. The findings were primarily consistent with spinal cord compression due to the presence of extruded disc material. Following conservative treatment failure, a right-sided C6-C7 hemilaminectomy was performed to remove the compression and sample the extradural material. Histological examination confirmed the presence of degenerated and partially mineralized disc material mixed with granulation tissue. This is the first reported case of cervical disc extrusion in a rabbit, confirmed by histological examination.

Surgical management of a lumbar far lateral intervertebral disc extrusion in a cat

Case summary

A 9-year-old male castrated domestic shorthair cat was presented with a 2-week history of acute, progressive left pelvic limb lameness. Gait evaluation revealed a grade 3/5 left pelvic limb lameness with no apparent orthopedic cause for the lameness based on orthopedic examination or radiographs. The neurological examination was otherwise normal. MRI revealed a left-sided L6-7 far lateral intervertebral disc extrusion with possible secondary neuritis of the L6 spinal nerve. A left-sided L6-7 foraminotomy was performed to remove the extruded disc material and provide additional space for the significantly enlarged nerve root. An L6-7 fenestration was also performed. The patient made an excellent recovery with near-complete resolution of lameness at 26 days postoperatively.

Relevance and novel information

This case report contributes to the growing body of literature on lateral intervertebral disc extrusion as an etiological factor in pelvic limb lameness in cats, particularly when neurological deficits are absent. Furthermore, the case report highlights the diagnostic utility of cross-sectional advanced imaging for cats with lameness for which an orthopedic or radiographic cause cannot be identified. Finally, this case underscores the efficacy of surgical intervention as a treatment option for cats with lumbar far lateral intervertebral disc extrusions that do not improve with medical management alone. This finding could have implications for future surgical approaches in cats with similar findings.

Outcomes of surgically and conservatively managed thoracolumbar and lumbosacral intervertebral disc herniations in cats

BACKGROUND

Limited information is available regarding intervertebral disc herniation (IVDH) and its treatment in cats.

OBJECTIVES

Describe outcomes after surgical or conservative treatment of cats with thoracolumbar and lumbosacral IVDH.

ANIMALS

Ninety-two cats from 2 referral populations (2012-2022) with compressive IVDH between the T3 and S1 vertebrae.

METHODS

Retrospective cohort study evaluating outcomes of surgical (49 cats) and conservative (36 cats) management of IVDH; 7 cats were euthanized at diagnosis. Outcome was assessed using hospital and referring veterinarian records and client questionnaires. Successful outcome was defined as regained or improved ambulation, urinary and fecal continence, and no requirement for analgesic medication.

RESULTS

Incidence of IVDH during the study period was 0.44% (92/20849). Surgical treatment resulted in 62% (6 weeks) and 74% success (6 months). Conservative treatment resulted in 54% (6 weeks) and 65% success (6 months). Neurological grade at presentation was higher in cats treated surgically (median, 2; range, 1-5) than in those treated conservatively (median, 2; range, 0-4; P = .001). Regardless of treatment type, cats suffering trauma were more likely to have a successful outcome 6 weeks after treatment compared with those without history of trauma (odds ratio, 5.3; 95% confidence interval, 1.05-26.78; P = .04). Neurological deficits remained in the majority of cats for both treatment types (92%, conservative; 86%, surgical at 6 weeks). Acute-on-chronic IVDH with characteristics of both extrusion and protrusion were identified in 10% of cats.

CONCLUSIONS AND CLINICAL IMPORTANCE

Conservative treatment could be as effective as surgical decompression in cats with thoracolumbar or lumbosacral IVDH.

Demographics, clinical findings and diagnoses of cranial thoracic myelopathies (T1-T6 vertebrae) in cats

OBJECTIVES

The aim of the study was to describe the patient demographics, clinicopathological features and presumptive or final diagnoses in cats with myelopathies between the T1 and T6 vertebrae.

METHODS

This retrospective multicentre case study enrolled cases between 2015 and 2022 that were diagnosed with myelopathies between the T1 and T6 vertebrae as the primary cause for the presenting clinical signs.

RESULTS

A total of 21 cases matched the inclusion criteria, 13 males (11 castrated and 2 entire) and 8 spayed females (median age 93 months; range 5-192). Most of the cases presented with a chronic and progressive history (76% and 86%, respectively), with a median duration of 29 days (range 1-2880). At the time of presentation, 90% of the cases were localised to the T3-L3 spinal cord segments based on neurological examination. The most common underlying pathology was neoplasia (42.9%), followed by inflammatory (24%), anomalous (19%), degenerative (9.5%) and vascular (4.8%) disorders. The most common location was T3-T4 (29%), followed by T2-T3 and T5-T6 (19% each). The cutaneous trunci reflex was normal in 86% of the cases and most of the cases (71%) did not show spinal discomfort upon admission.

CONCLUSIONS AND RELEVANCE

Neoplasia was the most common cause of cranial thoracic myelopathy in this study. The lack of pathognomonic clinical signs for this specific region highlights the importance of assessing the entire thoracolumbar region up to and including at least the T1 vertebra when investigating cases with signs consistent with a T3-L3 myelopathy.