SPINE - disc herniation Flashcards
Recovery of ambulation in small, nonbrachycephalic dogs after conservative management of acute thoracolumbar disk extrusion is associated with MRI degre resolution of the compression
No
What are the 3 MRI signs suggestive of PMM?
Length of T2-weighted hyperintense spinal cord change
HASTE signal loss
Shorter compressive lesions (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 was more common in the PMM group and the difference approached significance
retrogene responsible for IVD degeneration?
FGF4L2, chromosome 12
The presence of 1 or 2 FGF4L2 copies in the absence of the FGF4L1 retrogene has an additive effect on the number of calcified IVD and a minor effect on vertebral geometry in NSDTR dogs. Data support the use of FGF4L2 phenotyping to reduce clinical disease in segregating breeds and to monitor the introduction of wild-type alleles into fixed breed populations.
hydromyelia is
1. cranial/caudal to IVDE
2. associated with
mostly cranial, acute lesions
Describe what are cervical jerks? What is the most common location of IVDE associated with cervical jerks?
Cervical jerk associated with cervical pain or myelopathy may represent myoclonus
Exclusively secondary to cranial cervical IVDE (50%: C2-C3)
How many dogs develop spinal walking after IVDH treated surgically without nociception > 96h? Median time for recovery?
Spinal walking: 14%
Median time for recovery: 30d
The longer the time taken to regain pain perception, the longer the recovery time.
What are the 2 factors associated with development of spinal walking in dogs with irreversible thoracolumbar spinal cord lesion?
Younger age (≤5y)
Lightweight (≤7.8 kg)
French bulldogs with scoliosis appear to be at higher risk to develop thoracolumbar intervertebral disc extrusion: true or false?
False
Only FB with kyphosis appear to be at higher risk to develop thoracolumbar IVDE
Give the 4 intra/postoperative pain therapies for IVDE surgery in dogs.
Which complementary approaches have been proposed?
Pain therapy
Epidural morphine
Erector spinae block
Fentanyl patch
Adjunctive pregabalin
Gabapentin: no benefit over placebo
Complementary approaches
Preoperative acupuncture
Postoperative electroacupuncture: no benefit
Pulsed electromagnetic fields
Harmonic blade for surgical approach
Minimally invasive surgery
What are the clinical risk factors for PMM in TL-IVDE?
IVDE of lumbar intumescence that progress to DPN paraplegic status
French Bulldog
Delayed surgery in DPN
What are the 7 clinical features suggestive of an antemortem diagnosis of progressive myelomalacia in paraplegic DPN dogs with TL-IVDE?
CTR cut-off ≥1–2 spinal cord segments cranial to the site of IVDE
Progressive CTR cut-off advancement
Weak to absent patellar reflexes with a disc extrusion located cranial to the lumbar intumescence
Weak to absent anal tone and perineal reflex with a disc extrusion located cranial to the lumbar intumescence
Loss of abdominal tone
Difficulty retaining sternal recumbency
Thoracic limbs paresis or proprioceptive deficits in the absence of an explanatory lesion
What are the 6 biomarkers suggestive of an antemortem diagnosis of progressive myelomalacia in paraplegic DPN dogs with TL-IVDE?
Serum GFAP (Se 75%, Sp 98%)
Serum pNfH (PMM: elevation at 24h)
Myelography with diffuse intraparenchymal contrast (typical)
T2 hyperintensity length > 4.57 * T2
T2 hyperintensity length > 6 * L2 (Se 45%)
SSTSE CSF:L2 length ratio > 7.4 (Se 85-100%, Sp 75%)
Length of cerebrospinal fluid attenuation
What are the positive and negative prognostic factors in paraplegic medium to large breed dogs with extensive epidural hemorrhage secondary to thoracolumbar disc extrusion?
Negative factors
Loss of pain perception
Increased number of vertebrae with HASTE interruption
Positive factors
More extensive decompression improves outcome
Overall, paraplegic medium to large breed dogs with DEEH have a less favorable outcome after surgical decompression than paraplegic dogs with TL-IVDE.
ATTENTION: not the case for French Bulldog!!!
What are the risk factors for adverse events during ventral slot decompression for cervical IVDD in dogs?
AE occurred in 9.9% of dogs that had VSD, and were significantly associated with perioperative hypotension, C7–T1 disc extrusions, surgeon experience, and NSAID usage.
Identification of a major postoperative AE is an indication for immediate diagnostic imaging studies, as 50% of dogs experiencing major AE required reoperation.
The presence of multiple GE signal void in spinal cord in stage 5 IVDE dogs is associated with:
No regain of nociception
The number of patients that regained ambulation was significantly reduced to 33.3% when multiple gradient echo signal voids were present.
There was no significant difference in the rate of developing progressive myelomalacia between groups.
At which step of IVDD surgery can see modification of SSEP? What are theses modifications?
Removal of multifidus muscle: decreased amplitude, increased latency
Removing disc material: increased amplitude
Spinal cord conduction is impaired by retraction of the multifidus muscles and improved by removal of disk materials.
Maintaining intraoperative SEP amplitudes above 50% of control may help avoid additional spinal cord injury during surgery.
What features are associated with paraspinal muscles changes in MRI in dogs with IVDE? What histopathological changes can be seen?
Intervertebral disk extrusion caudal to L1 and a higher neurological grade was associated with the presence of muscle changes.
No association with the degree of compression or epidural hemorrhage
Histopathology revealed mild to moderate acute muscle fiber degeneration with edema and necrosis in three of five samples.
What is the reextrusion rate in adjacent intervertebral spaces after multiple vs. single site fenestration?
Multiple site fenestration: 7.5%
Single site fenestration: 18%
What MRI finding has been found to be a positive predictive factor for absence of development of progressive myelomalacia in thoracolumbar myelopathy with absence of deep pain?
1.Ratio of length of CSF attenuation : length of L2 in sagittal T2 images.
2.Ratio of length of CSF attenuation : length of L2 in sagittal single shot turbo spin echo pulse sequence images.
3.Ratio of length of intramedullary intensity : length of L2 in sagittal T2 images.
4.Ratio of length of intramedullary intensity : length of L2 in sagittal single shot turbo spin echo pulse sequence images
2.
What are the 2 most common location of foraminal and far lateral TLS-IVDE? What are the 2 most represented breeds?
97%: L5-6 & L6-7
Dachshund & mixed-breed
From the following statements, choose the TRUE.
- The presence of intercapital ligament connecting rib heads T2-T10, running dorsal to the annulus fibrosus and ventral to the dorsal longitudinal ligament, results in extremely low prevalence of IVD herniations in the cranial thoracic region in all breeds.
- German shepherds are less likely than other large breed dogs to have spinal cord compression due to cranial thoracic disc herniation
- T3T4 disc space has an increased risk for compression and herniation in German shepherd dogs
- German shepherd dogs are more likely to have higher scores for disc degeneration in cranial thoracic region than other large breeds of dogs.
3.
Is IVDD recurrence more frequent in cervical or TL spine in surgically treated French Bulldog? In young or old ones?
Recurrence of IVDD can be expected in more than half of French Bulldogs affected by IVDD. Especially young (≤ 3 years) French Bulldogs are prone for recurrence in cervical spine. Almost every fourth patient with IVDD suffers from a recurrence within 12 months. Future dog owners should be informed about the risk of IVDD and the early onset of recurrences in French Bulldogs.
What are risk factors for slower recovery of ambulation in non-ambulatory with deep pain perception in IVDH dogs?
Duration of surgery
Neurological (Frankel) grade at presentation
What are the factors that increase the odd of spinal shock in dogs?
Decreasing weight
Decreasing duration
Increasing PL tone
Paraplegia
In dogs with acute TL-sCI, reflexes are normal or improved in all dogs by 1 month: true or false?
False
14/15 (93%) dogs had improved or normal reflexes by 60 days post injury.
Which spinal cord segment is associated with spinal shock in dogs? What is the most commonly diagnosed aetiology?
Thoracic
“Thoracic lesions were significantly more likely to result in spinal shock when compared to lumbar lesions.”
Fibrocartilaginous embolism (41%)
“Fibrocartilaginous embolism was the most commonly diagnosed etiology (7 of 17 dogs), and was more common in the thoracic spine compared to in the lumbar spine. Six of 17 dogs (35%) were diagnosed with intervertebral disk herniation; 4 of 17 dogs (24%) with suspected acute noncompressive nucleus pulposus extrusion.”
Presence of spinal gradient echo signal void in dog with stage 5 IVDE is associated with:
Developpement of myelomalacia
Regain of nociception
Regain of nociception
59.8% of patients regained nociception within the study period. This number was significantly reduced to 33.3% when multiple gradient echo signal voids were present (compared to 67.3% of dogs without signal voids)
Risk factor for paraspinal muscle alteration on MRI in dog with IVDE
Caudal to L1 IVDE, higher neurological grade
No association with degree of compression or epidural hemorrhage
Muscle fiber degeneration with edema and necrosis.
When are somatosensory evoked potentials are modified during IVD surgery
Amplitude decreased + latency increase with removal of multifidus muscle
Amplitude increase after removing disc material
risk factor for HNPE compared to others cervical affection, IVDE
other myelopathy
HNPE were more likely to be:
- older and of lower weight
- nonambulatory
- have signs of central cord syndrome
- nonlateralizing signs
compared to dogs with IVDE,
- lower pain scores
- require mechanical ventilation
