CERVICAL+THORACOLUMBAR COLUMN: 31, 32 Flashcards
5 SIGNS of animal with spinal cord disease
(1) reduction or loss of voluntary movement
(2) spinal reflex abnormalities
(3) alterations in muscle tone
(4) muscle atrophy
(5) sensory dysfunction
describe a “two engine gait”
difference in stride length between thoracic and pelvic limb (C6-T2 lesion)
a cervical lesion will always determine a worst motor disfunction in the thoracic limbs compared to pelvic limb. T or F
F, descending upper motor neuron tracts to the pelvic limbs are more peripherally located in the spinal cord; animal presents with ambulatory paresis that apparently affects only the pelvic limbs, could represent mild cervical spinal cord dysfunction
What is a central spinal cord syndrome?
Animal will present with more profound motor dysfunction in the thoracic limbs than in the pelvic limbs:
The disparity is often due to a lesion affecting the central aspect of the spinal cord, which would affect the white matter deeper in the spinal cord
reduced flexor withdrawal (thoracic limb) reflex always indicate a lesion between C6 and T2. T or F
F: can be in up to 34 % of dogs C1-C5 lesion.
Spinal location associated with Horner Syndrome
C6-T2 (more commonly T1-T3)
describe briefly the paramedial approach to the cervical column
1) right sternocephalicus muscle is spearated to right sternohyoideus
2) exposure longus colli muscles and longus capitis muscle
Name in sequence the muscles encountered during lateral approach to the cervical column:
1) cutis
2) platysma
3) expose brachiocephalicus and trapezius
4) incision parallel to brach. fibers
5) exposure in the cranial cervical region of splenius and serratus ventral
6) blunt division and ventral retraction serratus ventralis
7) exposure longissumus crevicis
8) ventral retraction longissimus cervicis
during a C1 C2 ventral approach a ventral incision is performed in the median line between the ………… muscle and …………muscle.
-trachea retracted to left
-Muscle retraction + carotid artery + internal jugular vein + vagosympathetic trunk right side
sternohyoideus muscle
sternothyroideus
the main movement between the occipital bone and the atlas is later-lateral. T or F
F, flexion and extension (yes joint)
the main movement between the atlas and the axis is rotational. T or F
T
Name the 4 legaments that attacches the ATLAS to occipital bone and axis
1) apical ligament (basioccipital)
2) alar ligamenys (occipital)
3) dorsal atlantoaxial (spine axis)
4) transverse ligament (dens axis)
agle beween atas and axis predictive of instability
< 162°
when DORSAL surgical approach for ATL-AX instability is contraindicated?
dorsal deviation of the dens
angle and length of ideal transarticular corridor between atlas and axis
40° mediolateral
20° ventrodorsal
7 mm median
Failure rate ventral vs dorsal techniques for ATL-AX stabilization
ventral: 44%
dorsal: 48%
does C5 contribute to brachial plexus?
Usually no (just C6-T2), however 24% dogs also C5
partial lesions to brachial plexus are more commonly cranial. T or F
F: more commonly caudal.
name in order the 6 types of injury to nerves
1) neuroapraxia
2) axonotmesi
3)neurotmesi (disruption axons+endoneurium)
4) neurotmesi (previous + perineurium)
5) neurotmesi, complete severed nerve
6) nerve avulsion
3 types of brachial plexus injuries
1) cranial portion (C6-C7, some times also C5)
2) caudal portion (T1-T2)
3) all brachial plexus
clinical signs associated with cranial brachial plexus injury
1) atrophy supraspinatus
2) atrophy infraspinatus
-loss shoulder movement
-loss elbow FLEXION
clinical signs associated with caudal brachial plexus injury
involves RADIAL NERVE! (92% of cases)
1) paralisys triceps
2) loss cutaneous trunci reflex)
3) Horner
-loss extend elbow
-loss extend carpus
common site for cervical vertebral disc extrusion
C2-C4 80%
C2-C3 44-59%
protrusion are more common in cervical column than thoracolumbar column. T or F
F. more common extrusions!
prevalence of nerve root signature in cervical extrusions
22-50%. really common. Uncommon tetraplegia.
the degree of spinal cord compression evident on MRI is undependent to both clinical signs and prognosis in cervical Hansen Type 1 extrusions. T or F
F. dependent to clinical signs, undependent to prognosis.
conservative treatement is recommended for:
a) neck pain only
b) recurrent neck pain
c) neck pain+concurrent neuro deficits
a only
ideal ventral slot dimensions
33% vertebral bodies length, 50% width (preferrably and 33%)
hypoventilation will occur more commonly in dogs with lesions between C…. and C…., especially undergoing. ……….decompressive laminectomy
2 and 4
dorsal
risk of recurrence in cases of cervical extrusion treated conservatively
36+%
name the two major patophisiological categories of cervical spondylomielopathy
osseous associated
disc associated
most commonly involved IVD spaces in wobbler syndrome
C5-C6, C6-C7
signalment and patogenesis of osseous associated wobbler
Young, large breed dogs.
-combination of vertebral malformation + osteoarthritic changes to zygoapophyseal joint
what is the difference between vertebral instability and dinamic compression?
a) instability: abnormal displacement secondary to normal load
b) dynamic lesion: lesion that worsten or improve depending on column position
differences between large breed and giant breed wobbler
GIANT: 3.8 years mean, 80% multiple sites compression. most common C6-C7, then C5-C6 (90%)
LARGE: 6.8 years mean, 50% multiple compression . most common C6-C7, C5-C6, C4-C5 (80%)
the use of distraction-stabilization for osseous compression in wobbler syndrome allows for regression of osseous and ligamentous lesions over time. T or F
F. 6 m and 2 y PO vertebral canal measurement remain unchanged.
probably just eliminate dynamic component of spinal cord compression
common surgical procedures for disc associated and osseous associated wobbler
DISC:
-static: ventral slot
-dynamic: distraction-stabilization
OSSEOUS (primarily static!)
-dorsal laminectomy
-cervical hemilaminectomy
width (to cranial vertebral body) of most ventral part of the slot in inverted cone technique
20%
postoperative neurologic deterioration in wobbler syndrome percentages:
-70 % worsened after surgery with dorsal laminectomy
-42% with ventral slot
what is the domino effect?
late postoperative complication after distraction-stabilization techniques (ventral slot appear to reduce indicence)
commonly 1 disc cranial or caudal to site, sometimes even more.
name two distractors used in spinal surgery
caspar distractor
modified gelpi retractor
how much disc should be left in place when a PMMA plug is used for distraction? if ventral slot is performed simultaneously?
a) 3-5 mm of intact dorsal annulus
b) gelatin sponge between spinal cord and PMMA
improvement and recurrence rate following surgical or medical therapy for wobbler syndrome
70 to 90% improve surgical
38 to 54% improve medical
overall recurrence surgical 24% (both direct and indirect techniques)
anatomy of extradural synovial cysts?
cysts originates from zygoapophyseal joint, are extradural
-synovial when have synovium like cells lining
-ganglion when no lining, result of mucinous degeneration of articular cartilage
Name the 3 long and 3 short ligaments of the vertebral column
Long:
1) supraspinous
2) dorsal longitudinal
3) ventral longitudinal
Short:
1) interspinous
2) intertransverse
3) yellow
Intercapital ligament from T2 to T11
What is usually the anticlinal vertebra?
T11
Surgical approach to cranial thoracic column
1) incision in dorsal tendinous raphe
2) retraction trapezius and rhomboideus
3) incise median line splenius (cr) and serratus dorsalis (cd
4) exposure nuchal ligament (cr), longissumus cervicis, longissimus thoracis and lomborum muscles
5) elevation epaxial musculature from spinal processes and articular processes
What differences are encountered between caudal and cranial approach to thoracic column?
caudal less muscolature
-> dorsal thoracolumbar fascia
-> expose multifidus muscolature
longissimus lomborum attach to accessory process from t11 to L7
where should spinal nerve, artery and vein be retracted during lateral approach to spine?
cranially.
what should be the more appropriate term when describing hemilaminectomy?
hemiarchectomy (lamina+pedicle)
Differences between Funkquist A, B, and modified dorsal laminectomy
A)
spinous process
laminae
articular processes
half of the dorsal portion of the pedicles
B)
spinous process
laminae
modified dorsal laminectomy)
laminae
spinous process
caudal articular processes
what is vacuum fenomenon on XRAY
gas radiolocency within intervertebral disk due to degeneration Rare nut highly specific
commonly encountered myelographic pattern
extradural
factors associated with mielograpy related seizures
1) large body size
2) cisternal myelography
Following intravenous administration of gadolinium-based contrast medium to dogs, herniated intervertebral disc material may enhance on ……..
T1W and T1W fat saturated images
dogs lacking T2W signal changes within the spinal cord recovered voluntary ambulation. T or F
T
only …….% of dogs with T2W hyperintensity > 3 times the length of the L2 returned to voluntary ambulatory status
20%
Name 3 potential advantages of routine CFS collection
1) abnormalities identified on imaging studies may not always be indicative of clinically significant disease.
2) some abnormalities observed with imaging are not pathognomonic; several disease processes may share similar imaging features
3) subarachnoid delivery of iodinated contrast medium for myelography is contraindicated in dogs with inflammatory central nervous system disease
4) biomarkers within the cerebrospinal fluid can provide information that is prognostic or diagnostic across several causes, including intervertebral disc herniation
success rate for medical management of IVDH
82-88% ambulatory
43-51% non-ambulatory
can partial lateral corpectomy lead to instability?
yes:
1) increase in ROM
2) neutral zone in flex7ext
3) lateral bending
4) further instability when combined with hemilaminectomy
mean time from surgery to ambulation in nonambulatory dogs
12.9 days
timing for surgery after loss of nociception is a good indicator as to or to not operate. T or F
F. no correlation, even after 48H loss nociception should be done diagnostics
prognostic indicators after surgery in dogs with absent nociception
recover nociception within 2 weeks good prognosis / contrary poor prognosis
Overall success rate (return to ambulation) for dogs operated with absent nociception
43 to 62%
common breed associated with cranial thoracic (T1-T9) intervertebral disc herniation
German shepherd
name some techinques used to prevent hemilaminectomy membrane formation
(hyaluronic acid sheet) > autologous free fat > gelatin foam
possible complications associated with disc fenestration
1) discospondylitis
2) pneumothorax
3) iatrogenic spinal cord/nerve roots or spinal nerves damage
4) vertebral instability
overall long-term recurrence rate in IVDH
20% (Mayhew), 3 years
dachsund>other breed
meaning of opacified IVD
at the time of surgery, each increase risk of recurrence 1.4 times. (if one dog has 5-6 opacified disks, 50% chances recurrence)
alternatives to fenestration for recurrence prophylaxis
1) laser disc ablation
2) chemonucleolisis
signalment of cats with IVDH
middle aged cats, no sex predilection
common site of extrusion in cats
2/3 in overall literature caudal lumbar.
(those in thoracic-lumbar region appear to be lighter in weight)
name the three nerves to the bladder
1) hypogastric
2) pelvic
3) pudendal
pelvic nerve anatomy
parasympathetic+sensory
detrusor.
preganglionic neurons in sacral spinal cord segment
pudendal nerve anatomy
somatic+sensory
ext urehtral sphincter, perineal musculature, anal sphincter, skin perineum
sacral spinal cord
hypogastric nerve anatomy
sympathetic
internal urtheral sphincter, pelvic (para) ganglia, detrusor
L1 to L4
damage to upper motor neurons bladder
URINARY INCONTINENCE:
Increased detrusors and ext urethral sphincter tone. large firm bladder
phenoxybenzamine or prazosin
lower motor neuron bladder
decreased detrusor muscle and external urethral sphincter tone, presenting as a large, soft bladder that is easy to express and overflows with minimal intraluminal pressure
predisposing factors to urinary tract infection in dog with spinal cord injury
1) sex
2) incomplete voiding
3) elevated intravesical pressure
4) prior dexamethasone administration
5) mucosal damage associated with catheter
6) contamination of the catheter
7) close proximity of the urethra to sources of potentially virulent microorganisms
8) retrograde flow of urine from the collection system to the urinary bladder
9) normal to alkaline urine pH
10) low urine osmolality
11) preexisting medical conditions
antibiotic for urine infection in dogs with spinal damage should be performed as in normal dogs. T or F
F: longer period (3-6 we), recultured after 2-3 days stop
Name 2 neurologic scores able to predict ambulatory status at discharge
1) Frankel score
2) Texas spinal cord injury score
What breed can have an inherited form of thoracic hemivertebra
German shorthaired pointer
breeds predisposed to spina bifida
manx cats
screw tail dog
spina bifida classification
occulta
aperta
cystica (when associated with meningocele, meningomyocele, myeloschisis)
breed predisposed to dermoid cyst (pilonidal)
dogs: rhodesian
cat: burmese cats
common sites for subarachnoid diverticula
cranial cervical, caudal thoracic
signalment of dogs with subarachnoid diverticula
younger adults (<18 m). pugs and Rottweilers
-thoracolumbar -> older, smal breed
-cranial cervical -> younger, large breed
breed predisposed to myelodysplasia (dysraphism)
Weimaraners. Young (1, 2 m) , non painful T3 L3 myelopathy