Chapter 53 - Vertebral column part 1 Flashcards
1
Q
what the new studies of imaging revealed concerning the angulation and subluxation of C3 and C4 on radiographs?
A
such as angulation or subluxation at C3 to C4 that suggest cervical spinal cord compression on plain radiographs, are not always confirmed as the site of compression on myelography
2
Q
Are changes in the articular processes of C5, C6, C7 a common findin and always responsible for neurologic problems?
A
No, changes seen in the articular processes of C5,
C6, and C7 may be associated with spinal cord compression
but they are also a common finding in horses without neurologic
problems and may be present in horses with ataxia attributable
to another cause or to compression at another site
3
Q
is there association btw OA of the caudolateral aspects of the caudal cervical facet joints and clinical symptoms?
A
In fact, there is no clear association between osteoarthritis of the caudal cervical facet joints and clinical symptoms. Recent postmortem study showed 18% with craniolat OA and caudal articular process in 52%
4
Q
what is the ideal surgical patient for spinal cord lesions?
A
young horse showing mild neurologic signs as a result of CVSM for a short period of time or a trauma patient exhibiting no or only minimal neurologic deficits
5
Q
what are the 2 materials most used for vertebral interbody fusion?
A
Kerf-Cut cylinder (KCC) or a LCP
6
Q
A
7
Q
What are the surgical approachs to the cervical vertebrae?
A
ventral, lateral, dorsal, lateral and dorsal
8
Q
Pateint position is crucial for vertebral sx, Describe how to position the horse for ventral approach
A
DR
extended neck and head held in position by foam cushion or custom made wedge pads that stabilize the neck in a vertical position
FL tied in flexed position and pulled caudally
Fluoroscopy or radio previous, during sx
9
Q
why is important that the markers, staples, are placed the closest to the x-ray cassete?
A
to prevent excessive distortion as a result of parallax, and they should be placed over the affected articulation as well as ventrally at the level of the incision
10
Q
What are the 2 recumbencies for the dorsal approach?
A
sternal recumbency with all four limbs flexed on a padded table and the head extended
positioning the horse in lateral recumbency with the neck in full flexion
11
Q
After aseptic preparation and imaging the incision in either dorsal and ventral will have to abaxially deviate the muscles. What instrument will you use?
A
Weitlaner retractors can be used to maintain access to the vertebrae
12
Q
In the ventral approach after skin incision centered over affected vertebrae what muscles were incised?
A
cutaneous muscle is incised, and the sternohyoid and** sternothyroid muscles** are separated on the midline to the level of the trachea, which is** retracted to the left** side
13
Q
In the ventral appraoch after cutaneous muscle, sternohyoid, stenothyroid muscles are separated how is the dissection continued?
A
blunt dissection is continued dorsad down to the** right side of the trachea, separating it from the carotid artery and vagosympathetic trunk**. The trachea and other structures are protected with moistened gauze pads. Weitlaner retractor is inserted and longus colli muscle accessed.
14
Q
longi colli can be mistaken with
A
esophagus
15
Q
which vessel you have to be careful in the caudal cervical region?
A
Before the fascia of the longus colli muscle is incised, all important vessels must be cauterized or ligated. An important branch of the carotid artery is located in the caudal cervical region. The fascia and longus colli muscle are subsequently incised to gain access to the cervical vertebrae
16
Q
describe the ventral access to the vertebra
A
DR
Incision of skin
Incision of cutaneous muscle, sternothyroid and sternohyoid muscles, ID trachea + separate vagosympathetic trunk and carotid artery
Moistened gauze to the trachea
Weitlaner retractor positioned at the cranial and caudal aspect of the incision
Cauterize important vessls - branch of carotid artery
incise longus colli muscle and gain acess to cervical vertebrae
*C3 be careful that esophagus can b mistaken with longi colli
17
Q
At what level is the esophagus in the midline?
A
At C3 level
18
Q
Describe the dorsal approach to the cervical vertebrae
A
20 to 30 cm incision through skin on dorsal midline
Incise subcutaneous tissue and fat overlying the funicular part of the nuchal ligament and expose the fibrous tissue of the ligament
Once you incised dorsal nuchal ligament place a self-retaining Finochietto or Balfour retractor
19
Q
Describe the lateral approach to the cranial recess cervical vertebrae Tucker 2021 Vs
A
slightly curved, 6 cm skin incision was made in a cranioventral to caudodorsal direction centered over the craniodorsal margin of the APJ, as identified using ultrasound.
The incision was continued through
-m. brachiocephalicus*
-*/m. omotransversarius,
- m. longissimus cervicis, dissection was directed toward the
palpable craniodorsal rim of the APJ
19 gauge needle was placed through the incision into the palpable joint space and the joint was distended with approximately 5 ml sterile polyionic fluid
stab incision was made with a number 11 scalpel
blade through m. intertransversarii** and the joint
capsule, to enter the cranial outpouching of the joint
Introduction of conical obturator and arthroscope sleeve craniodorsal to caudoventral angled 60º with 4 mm 30º endoscope
Fluid distension 60mmHg
created approximately 20 mm cranial and 20 mm ventral
to the arthroscope portal
20
Q
For which condition do you go for lateral approach?
A
treatment of cervical articular process joint osteochondrosis,
21
Q
describe the surgical approach to the caudodorsal recess according to Tucker et al 2021
A
5 cm skin incision was created in a slight craniodorsalto-
caudoventral plane at the level of the caudodorsal border
of the **APJ, as identified by intraoperative ultrasound
imaging
The joint was distended with fluid and a stab
incision created through m multifidus cervicis and the
joint capsule, similar to the approach to the cranial
recess.
arthroscope was inserted into the joint, angled in a caudodorsal to cranioventral direction,
An instrument portal** was
created **caudoventral to the arthroscope portal **but its
close proximity to the arthroscope invariably resulted in
the creation of a single mini-arthrotomy
22
Q
Tucker et al 2021 how were retrieved the osteochondral fragments?
A
Smaller fragments were retrieved with 4-6 mm Ferris-
Smith rongeurs. Larger fragments were removed with a
curved hemostat
23
Q
description and diagnosis
A
FIGURE 3 Orthogonal
transverse (A) and sagittal
(B) multiplanar reconstructed CT
images centered on the right C5/C6
articular process joint of the same
horse (Table 1, case 4). Circular,
mineral-attenuating loose bodies are
situated in a cranioventral location
within the joint
24
Q
For the dorsal approach to the cervical vertebrae, what is often profuse initially?
A
Hemorrhage
25
What aids retraction in the dorsal approach to the cervical vertebrae?
Finochietto or Balfour retractors
26
What is the lateral an dorsal approach to the thoracolumbar vertebrae?
skin incision located** 6 cm lateral to the midline** with the **dorsal spines** exposed by dissecting the s**upraspinous ligament off its dorsal edge**
modification of this technique uses a **midline approach** for the skin incision and the dorsal spines are exposed by **splitting the supraspinous ligament**
The** supraspinous ligament **is split longitudinally and the ligament and longissimus dorsi muscle attachments are sharply dissected off the affected processes and partly off the adjacent processes beyond the impingement lesions
27
what is the dorsal approach to the sacrum and the coccygeal vertebrae plate fixation? how do you close it?
longitudinal and along the midline
For the** dorsal sacral and coccygeal approach,** only the subcutaneous tissue is **sutured in a simple continuous pattern** and the skin is apposed using a continuous intradermal pattern.
28
what instrument is used in the dorsal approach to the coccygeal vert and sacrum?
pointed reduction forceps
29
how do you close the ventral cervical approach
the **longus colli muscle** is apposed followed by the ventral cervical muscles, the **cutaneous muscle** together with the subcutaneous tissues, and finally the skin.
When **closing the dorsal cervical approach**, the **laminar portions of the nuchal ligament** come together and need to be apposed only along the most superficial aspect of the ligament using absorbable monofilament suture material in a simple continuous suture pattern.
30
how do you close the dorsal cervical approach
The funicular portion of the nuchal ligament, the subcutaneous tissues, and the skin are all apposed using absorbable suture material in a simple continuous suture pattern in each layer. When
31
how do you close the lateral cervical approach?
When finishing the lateral cervical approach, the **joint capsule** is closed in a **simple interrupted pattern** and the **muscle layers** are closed in **two layers**. A **sterile stent bandage** is sutured over the incision for protection of the incision during recovery and replaced with a sterile dressing when the horse has returned to its stall. **Placement of a suction drain **is an option to prevent seroma formation, and a neck bandage can be applied but is not mandatory
32
How do you close the lateral and dorsal thoracolumbar approach?
the** supraspinous ligament** is sutured in a **simple continuous pattern** and the skin is apposed using a continuous intradermal pattern
33
how should be performed the recovery of horses after cervical intervention?
Hand recovery of horses with tail and head ropes is preferred by many surgeons
34
Steroids can be administered when the grade of ataxia is greater than
3 (out of 5 according to Mayhew’s grading system15)
35
Sling recoveries are sometimes necessary, especially in horses with
severe ataxia (grade >3).
36
what are the postoperative care following cervical sx?
Hay and feed should be offered at shoulder level
4-6 w stall rest After this time, hand-walking can be initiated
After 60 to 90 days the horse should be turned out for at least 6 months or until clinical signs resolve
37
How much time can take the cervicals to fuse following surgery?
1 year
The owner and trainer should be warned that it may take at least 1 year before the clinical signs resolve and that a carefully executed rehabilitation program is of utmost importance for a good result.
38
cervical fractures are common in young or adult horses?
foals and young
possible explanation: exuberant nature of most foals and young horses and their smaller muscle mass compared with mature horses; the musculature has a considerable protective and stabilizing effect on the vertebral column.
39
Which type of vertebral fractures is more common in adult horses? Where?thoracolumbar fractures common in young or adult?
Thoracolumbar fractures
The most common sites of vertebral body fracture are the first three thoracic vertebrae, followed by the thoracic vertebrae in the T12 area = greatest lateral bending and axial rotation
40
A vertebral fracture may involve the
vertebral body
vertebral arch
facet joints
spinous process
41
describe image and diagnosis
Figure 53-6. Transverse computed tomography image of a fracture of the axis, which was missed with radiographic examination. The black arrow shows the fracture line of the vertebral body.
42
Projection and diagnosis
Figure 53-5. Oblique radiographic view showing a fracture of the atlas with ventral displacement of the fragments (arrow).
43
projection and diagnosis
Figure 53-7. (A) Laterolateral radiographic view showing fracture (arrow) of the dens. (B) Laterolateral radiographic view showing fracture of the dens (arrows) with severe displacement of the articulation between the atlas and the axis. ([
44
what are the different traumatic injuries to the cervical spine
1) fracture to the atlas and axis
2) Atlantoaxial subluxation and luxation
3) Cervical vertebral fractures (C3 to C7)
4) Fractures involving one or 3 vertebra
5) Fractures of the articular process
45
Which surgical approach involves the separation of the sternohyoid and sternothyroid muscles on the midline?
Ventral approach to the cervical vertebrae
46
Which vertebrae differ greatly from the remaining cervical vertebrae?
Atlas and axis
47
What is the recommended course of action for horses with severe disruption of the thoracolumbar spinal cord?
Euthanasia
48
What is a common cause of vertebral fractures in horses?
Trauma
49
How can vertebral fractures without trauma occur?
such as lymphosarcoma, spinal abscess, or septicemia, or occur after failure of surgical intervertebral stabilization
50
What is a common surgical technique for repairing fractures of the dens?
A) Dorsal laminectomy
B) Ventral atlantoaxial fusion (plate LCP or screws)
C) External fixation with Steinmann pins
51
At what age does the physis of the dens or odontoid process close in horses?
8 to 12 months
52
How do you diagnose fractures of axis and atlas?
These injuries cause **neck pain and stiffness.**
Some patients exhibit **no neurologic deficits**
Radiographs a (lateral, oblique, and ventrodorsal projections) Myelography, and if available, CT scanning (Figure 53-6) or MRI
53
what is the goal of surgery to the atlas or axis fracture?
The goal of surgery is to provide decompression at the fracture site by realigning the vertebrae and providing stability through some form of fixation
54
what are the ligaments that attach axis to the atlas?
**Apical
Transverse
Alar ligaments**
55
Neurologic deficits from axis and atlas trauma
range from a stiff gait and splinted neck to total tetraparesis or even sudden death
56
The prognosis for recovery from atlas and axis injury is correlated to
severity to spinal cord damage
with only paresis having favorable survival prognosis
57
Nonsurgical management of atlas/axis fracture can be attempted?
yes with **stall rest** and **AINS** and with time f**ibrous union** btw the dens and axis may develop and enuro deficits decrease. late-developing neurologic deterioration indicates that proliferative bony callus or **soft tissue hypertrophy can cause cord compression**
58
Which approach is NOT described for the surgical repair of a fractured axis?
Lateral approach, only dorsal and ventral are described
59
Dorsal laminectomy of the caudal half two-thirds of the dorsal arch of atlas is done why?
to relieve the spinal cord compression created by a fracture callus and may result in a long-term improvement in the neurologic status of the horse
60
Describe the placement of LCP plate by ventral approach to correct atlas or axis fracture
**30-cm midline ventral** skin incision centered on the vertebra with radio guidance
**Flattened the ventral spinous process** with rongeur or curved osteotome
**Align the ventral vertebr**a is corrected and maintained with **bone-holding forceps**
Depending on size of patient: broad or narrow 3.5/4.0-mm ir **4.5/5.0-mm LCP** is contoured to the shape of vertebra to the ventral aspect of C2
**One cortex screw** inserted into each **fragment in load fashion**
Length of screws estimated with fluoro and remaining holes filled with **LHS screws**
**extremly important to avoid spinal cord damage when inserting the screws**
61
what other tx for atlantoaxial stabilization beside ventral LCP has been described?
Ventral stabilization of the atlantoaxial junction by **inserting two 6.5-mm cancellous screws** across the articulation after removal of cartilage from the articular surfaces - risk vertebral
arteries and first cervical nerves abaxially
**dorsal plate inserted in the dorsal spinous process** in case of **fractures of the body of C2**
62
# cerv
projection and diagnosis
(A) Laterolateral radiographic view showing a complete transverse fracture (arrow) of the second cervical vertebra. (B) Dorsoventral radiographic view.
63
treatment
(C) Laterolateral radiographic view of the axis after fixation of the fracture with a narrow 7-hole 4.5-mm dynamic compression plate.
64
projection and diagnosis
Figure 53-10. (A) Laterolateral radiographic view showing subluxation of the atlantoaxial joint (arrow). (B) Laterolateral radiographic view showing complete luxation of the atlantoaxial joint
65
what are the pathologies common in atlas and axis region?
1) vertebral fracture (body, arch), spinous process, articular process,
2) subluxation and luxation
66
What complication can occur from drilling screw holes in the vertebral arches of the atlas?
Penetration of the spinal canal
67
What age range is most commonly affected by subluxation of the atlantoaxial articulation in horses?
Up to 3 years of age
68
What indicates a complete luxation of the atlantoaxial articulation?
Displacement of the dens ventral to the atlas
69
what are the clinical signs of atlas or axial subluxation?
The neurologic signs can be **acute or chronic** and can vary in severity from **mild ataxia to recumbency.**
The horse ma**y have abnormal head** and **neck carriage** and r**esent manipulation **of the neck, and there may be **local swelling at the site of acute injurie**s
70
when is the nonsurgical treatment is an option?
Nonsurgical treatment is indicated for acute complete luxations of **C1 to C2**, when closed reduction is **possible under GA **in **acute injuries**
71
what is the surgical option for horses that show neuro deterioration or persistance of neuro deficits in C1 or C2 subluxation?
Horses with atlantoaxial subluxation can be successfully treated with **subtotal dorsal laminectomy**. Removal of the **caudal two-thirds** of the dorsal arch of the atlas relieves spinal cord compression and allows preservation of the normal range of motion of the atlantoaxial articulation. A portion of the dorsal atlantoaxial ligament is left intact
**NO SX TX for complete atlantoaxial luxation**(AUER but Schulze 2019 describes VS)
Arthrodesis with human disal femural plate -** chronic cases**
72
diagnosis and projection
Figure 53-12. Laterolateral radiographic view showing subluxation between C2 and C3 (arrow).
73
Figure 53-13. Laterolateral radiographic view showing chronic fracture of the cranial articular process of the fourth cervical vertebra. The sclerotic and cystic changes are signs of nonunion, which are depicted by the black arrows.
74
Figure 53-8. Laterolateral radiographic view showing fixation of the subluxation of the atlantoaxial joint with a human distal femur locking compression plate. This is the same patient as shown in 53-7, B. (B) Slightly oblique radiographic view showing fixation of the subluxation 15 months postoperatively of the patient shown in 53-7, B. Bone bridging between the atlas and the axis can be observed (black arrow). Bone lysis around many screws and the plate are clearly evident (white arrows).
75
Figure 53-15. Postmortem specimen of a comminuted fracture of C4 with severe spinal cord damage. The white arrow shows the fracture of the fourth vertebra and the black arrow shows the severe damage to the spine at the location of the vertebral fracture.
76
what happened?
Figure 40.3 Chronic fracture of the atlas with secondary spinal cord compression in a two‐year‐old Quarter Horse. The horse was injured
during a training incident as a yearling. (A) Lateral myelographic image shows multiple bony densities in the ventral arch of the atlas
(white arrows), massive thickening of the dorsal arch of the atlas, and compression of the spinal cord (arrowheads). (B) Intraoperative view
shows laminectomy of the caudal two‐thirds of the dorsal lamina of the atlas. (C) Completed laminectomy prior to insertion of nuchal fat.
77
Cranial cervical congenital subluxations name them and recommended tx
1. **occipitoatlantoaxial malformation (OAAM**) - arabian horses
2. **atlantoaxial subluxation (AAS)** - absence or separation of dens from axis
3. and **atlantoaxial instability (AI)**
congenital absence of the dens
Tx: **standard LCP** or** dstal femur LCP** for OAAM
subtotal dorsal laminectomy of the impinging dorsal arch for AAS
No tx for AI
78
Figure 40.2 Fracture of the atlas in an adult horse with upper neck stiffness but no neurologic deficit. (A) Lateral radiograph identifies
non‐destabilizing fractures (arrows) in the lateral arches of the atlas. (B) Oblique radiograph indicates that the fracture extends to the
cranial foramen of the atlas (arrows).
79
Figure 40.2 Fracture of the atlas in an adult horse with upper neck stiffness but no neurologic deficit. (A) Lateral radiograph identifies
non‐destabilizing fractures (arrows) in the lateral arches of the atlas. (B) Oblique radiograph indicates that the fracture extends to the
cranial foramen of the atlas (arrows).
80
What is a necessary condition for atlantoaxial luxation to develop?
Complete disruption of the ligamentous attachments of the dens
81
Total luxation of the C1 and C2 was corrected with placement of TLACP plate describe the surgical procedure by Schulze
**20-cm skin incision** was made on ventral midline, **centered over the atlas and axis**
The **musculus cutaneous colli**was bluntly dissected, and the **sternohyoid and sternothyroid muscles** were separated in midline.
After the **trachea was identified**, it was **retracted to the left** with **Langenbeck retractors**
blunt dissection was continued in a **dorsal direction,** to the **right side of the trachea.** The **carotid artery and vagosympathetic trunk** were identified and carefully retracted by using a **Penrose**
drain. The aponeurosis of the **longus colli muscles** was incised, and the muscles were retracted with **Hohmann retractors** to
gain access to the **ventral aspect of the atlas** and to expose the
luxated dens of the axis**(Figure 2).
With the aid of the **pulley system**, traction was applied to
the **occipital area** of the head of the horse in an attempt to perform **open reduction of the luxation**. Reduction was supported by **placing a Hohmann retracto **between the caudal aspect of
the atlas and the dens by using it as a lever to gently walk the
dens back to its physiological position. **The reduction of the
luxation was unsuccessful despite the application of strong
traction**, and the **dens axis was subsequently excised with an
oscillating saw** . The alignment of
the atlas and the axis was achieved after removal of the
dens axis. The v**entral spinous process of the body of the axis** was flattened by using a **curved osteotome** and **bone rongeurs**. The** cartilage
of the caudal articular joint surface **of the** atlas**, and the cranial articular surface of the axis was removed with a curette.
The alignment of the atlas and axis was finally optimized under
fluoroscopic guidance and maintained with bone reduction forceps (Figure 3). A **4.5-mm six-hole T-locking compression
plate (T-LCP) was contoured** and fixed to the caudal aspect of the atlas with a **5-mm locking head screw** (36 mm) that was
inserted in the **central screw hole at the T end of the plate**. The **correct length of the screws** was determined
with **fluoroscopic guidance.** The s**econd screw was a 4.5-mm cortical screw (28 mm) **placed in **load position** in the cranial
aspect of the axis (fourth screw hole). **Four 5.5-mm cortical screws** (68 mm) were placed in **lagfashion**
across the **atlantoaxial articulation** to
provide additional stability. The m**edial and lateral cortical
screws were tightened simultaneously to maintain axial alignment.**
The r**emaining screw holes of the T-LCP** were filled with
**locking head screws** with the e**xception of the second screw
hole of the plate, which was positioned over the atlantoaxial
articulation** (Figure 4a,b).
Prior to closure, the wound was **flushed** with sterile polyionic
fluids. Th**e longus colli muscles** (USP 2 polyglactin
910), **ventral cervical muscles** (USP 2 polyglactin 910),
**cutaneous muscle together with subcutaneous tissue** (USP
2-0 polyglyconate), and** skin** (USP 2-0 polypropylene)
were apposed in simple continuous fashion. The surgical
site was protected with a stent
82
diagosis and projection
FIGURE 1 Left-lateral radiograph of a complete luxation of the
dens axis in an American quarter horse yearling. The dens axis can be
identified ventral to the ventral arch of the atlas. A, C1 (atlas); B, C2
(axis); a, dens axis; b, cranial aspect of the vertebral body of C2; c,
caudal aspect of the vertebral body of C2; d, vertebral canal of C2; e,
articular process joint C2/C3; f, concavity of atlas where the dens
should be located; g, dorsal spinous process of C2
83
what is happening?
FIGURE 2 Ventral intraoperative photograph of the luxated
dens of the axis. The aponeurosis of the longus colli muscles was incised, and the muscles were retracted laterally with Hohmann retractors to gain access to ventral aspect of the atlas and the axis. a, cranial; b, caudal; c, Hohmann retractor; *, luxated dens of the axis
FIGURE 3 Ventral intraoperative photograph of the bone
reduction forceps keeping the alignment of atlas and axis after removal of the dens axis. The ventral spinous process of the body of the axis has been flattened, and the 4.5-mm six-hole T-locking compression plate is in position. a, cranial; b, caudal; c, bone reduction forceps; *, removed dens of the axis with T-plate positioned over the atlantoaxial
articulation. Schulze
84
What was the surgical technique used to stabilize the atlantoaxial articulation in the case report?
A) Manual reduction
B) 4.5-mm T-locking compression plate (T-LCP)
C) Spinal fusion
D) External fixation
B) 4.5-mm T-locking compression plate (T-LCP)
85
What complication is commonly associated with complete atlantoaxial luxation in horses?
A) Fracture of C4 and C5
B) Poor prognosis for survival
C) Respiratory distress
D) Increased instability of the neck
B) Poor prognosis for survival
86
What percentage of vertebral fractures in horses involve the cervical vertebrae?
Approximately 50%
87
What are the most common types of cervical vertebral fractures?
Compression fractures of the vertebral body and articular process fractures
88
What typically causes cervical vertebral fractures in horses?
Head-on collisions or falls over jumps or obstacles
89
At what age do the caudal cervical vertebral body physes close in horses?
4 to 5 years old
90
What is a possible consequence of severe trauma to the cervical vertebrae?
Fracture and elevation of the pedicles of the caudal articular process
91
How do the neurologic effects of cervical vertebral fractures manifest?
Range from mild ataxia to quadriplegia or sudden death
92
Why is obtaining radiographs in standing horses preferred?
To avoid anesthesia and the risk of displacing fracture fragments
93
What condition can develop in horses with articular facet fracture treated conservatively?
Torticollis
94
What issue can arise after fusion of affected intervertebral articulation in horses with cervical fractures?
Development of a domino effect
95
What is a challenge when performing screw fixation in vertebral bone, especially in foals?
Gaining secure screw purchase
96
What is an advantage of using an LCP for ventral fusion compared to a DCP?
It does not need to be tightly contoured to the bone along the entire length of the plate
97
In cases of pedicle fractures with bony callus impinging on the spinal canal, what is the indicated surgical intervention?
Dorsal laminectomy or ventral stabilization
98
What is the risk associated with dorsal laminectomy for decompressing the spinal canal in horses?
Risk of refracture and worsening neurologic signs due to surgical trauma
99
What tool is used for reducing a fracture involving only one vertebra?
Pointed reduction forceps and strong digital pressure
100
What type of plate is recommended for fracture fixation in a single vertebra fracture?
Either an LCP or a DCP
101
What is the aim of treatment for fractures involving two vertebrae?
Fusion of the fractured vertebrae and possibly the next adjacent caudal vertebra
102
What is the preferred treatment approach for articular process fractures?
Intervertebral fusion with plates applied to the ventral aspect of the involved vertebrae
103
Accordingle to Tucker et al Surgical removal of intra-articular loose bodiesfrom the cervical articular process joints in 5 horses, the most difficult and most common recess affected was:
A. cranial recess of articular process joint
B. caudal recess of articular process joint
B. caudal recess of articular process joint
104
What is typically involved in the treatment of fractures over two vertebrae?
Partial removal of the ventral spine of each affected vertebrae and drilling holes
105
what complementary exams are useful when cervical fractures are suspected?
conventional radiography, ultrasonography, nuclear scintigraphy, and fluoroscopy using a novel C-arm were used to successfully diagnose a cervical articular process
High-quality radiographs, including oblique and ventrodorsal views, and CT scans are necessary to appreciate the fracture configuration, particularly in vertebral body fractures where there can be multiple fracture lines and minimal displacement
In horses that have more than one vertebra fractured, a myelogram may be useful to determine the site or sites of spinal cord compression
106
name the instrument
Langenbeck
107
Figure 53-16. Laterolateral myelographic view showing static compression of the spinal cord at C7 in a horse that sustained a fracture of C7 2 years previously. The black arrows indicate the ventral compression of the spine at the location of the callus formation.
108
Diagnosis and projection
Figure 53-17. (A) Preoperative laterolateral radiographic view showing an oblique displaced fracture of the caudal part of the C4 involving the disc (black arrow). (B) Laterolateral radiographic view taken 3 years after surgical fixation with a narrow 5-hole 4.5/5.0-mm locking compression plate.
109
treatment?
Figure 53-17. (A) Preoperative laterolateral radiographic view showing an oblique displaced fracture of the caudal part of the C4 involving the disc (black arrow). (B) Laterolateral radiographic view taken 3 years after surgical fixation with a narrow 5-hole 4.5/5.0-mm locking compression plate.
110
There are several reports of successful repair of displaced cervical fractures. How?
With ventral LCP along with intervertebral fusion
111
advantage of LCP over DCP in the treatment of cervical fractures
LCP only needs to be with minimal contou to the bone which mean less bone need to ve rremoved from ventral spine
luting with polymethyl methacrylate (PMMA) is not required to achieve plate contact, which is usually necessary with a DCP
112
which parts of LCP have to be in contact with the bone?
The cranial and caudal end of the LCP however should be well apposed to the bone to prevent dorsal implant migration with subsequent spinal cord damage
113
How to correct a fracture involving 1 vertebra?
manipulation using pointed reduction forceps and strong digital pressure. An LCP or a DCP is used for fracture fixation, and depending on the size of the patient, a narrow or broad 3.5- to 4.5-mm DCP or a 3.5/4.0- or 4.5/5.0-mm LCP is used.
The plate should be as long as possible to achieve optimal stabilization
Cortex screws are used in lag fashion at the level of the fracture to compress the fragments
114
How to correct a fracture with 2 vertebrae involved?
In fractures that involve two vertebrae (see Figures 53-17 and 53-18), fusion of the fractured vertebrae and possibly the next adjacent caudal vertebra is attempted.
Following partial removal of the ventral spine of the body of each affected vertebrae, the disc material must be removed, at least partially, by drilling multiple holes with a 5.5-mm drill bit under radiographic guidance or using curettes. In fractures that extend over two vertebrae, transarticular cortex screws are inserted in lag fashion through the plate.
The remaining holes are filled with locking screws
115
How do you approach fractures of articular procesS?
Access to the articular processes is extremely difficult, and therefore fixation or fragment removal is not recommended. Intervertebral fusion with plates applied to the ventral aspect of the involved vertebrae should be attempted if deterioration of neurologic signs occurs.
116
Describe the placement of LCP fixation in the cervical fractures
Disc removal is important
bone graft in the ventral intervertebral space can be good
s**tandard 4.5/5.0-mm narrow **or **broad 8-hole LCP** is used with **5.0-mm self-tapping locking head screw**s under radiographic control.
**Self-drilling and self-tapping screws should not be used**, because a considerable amount of threaded screw length is lost because of the drilling device at the tip of the screw.
Most **plate holes are filled with 5.0-mm locking head screw**s, but if a nonperpendicular angulation is necessary, 4.5- or 5.5-mm cortex screws are inserted as position screws (Figure 53-20). It is important to use the longest screws possible and to place the central cortex screw across the intervertebral articulation as a position or lag screw (Figure 53-21).
117
does the application of the plate ventral goes accordingly to AOVET principles?
The application of a plate to the ventral aspect of the bone violates the principle of applying the plate to the tension side of a bone. As a result, flexion of the neck predisposes the fixation to failure by causing screw retraction from the bone. The permanent cyclic stress to the plate might contribute to breaking of the plate and screws (Figure 53-23).
118
what happened?
Figure 53-22. Inadvertent penetration of the spinal canal and spinal cord during drilling (arrow).
119
what happen?
Figure 53-23. Five months postoperative laterolateral radiographic view of the cervical spine with a narrow 14-hole 4.5/5.0 locking compression plate applied to the ventral aspect of C3 to C5. The plate broke at two sites (black arrows) and one 4.5-mm cortex screw is broken as well (white arrow). In addition, the locking head screw broke through the combi plate hole (grey arrow). Some remodeling callus is present.
120
Hohmann retractor
121
Why in Schulze et al 2020 it was placed four 5.5-mm cortical screws?
73% of total axial rotation of cervical spine occurs btw first and second cervical vertebrae.
Four 5.5-mm cortical screws were placed in lag
fashion across the articular surface of the axis and the atlas - to provide additional rotational and also dorsal stability
122
describe the image
(A) Bone phase gamma scintigraphic lateral
images of the cervical vertebrae showing increased
radiopharmaceutical uptake of the right C4/C5 and C5/6 APJs. Tucker at al
123
projection and diagnosis
124
describe image and diagnosis
FIGURE 3 Orthogonal
transverse (A) and sagittal
(B) multiplanar reconstructed CT
images centered on the right C5/C6
articular process joint of the same
horse (Table 1, case 4). Circular,
mineral-attenuating loose bodies are
situated in a cranioventral location
within the joint Tucker et al 2020
125
diagnosis
126
describe according to Tucker et al 2021 where is performed the skin incision and instrument portals to the cranial articular process joint
LR - affected APJ uppermost and neck in neutral position
5L fluid bag placed beneath the neck to open the joint space
slightly curved, **6 cm skin**
incision was made in a **cranioventral to caudodorsal direction**
centered over the craniodorsal margin of the APJ, as
identified using ultrasound
127
which muscles are incised in the arthroscopy of the cranial recess of the APJ
through **m. brachiocephalicus/**
**m. omotransversariu**s, and **m. longissimus cervicis**, dividing muscle fibers where possible.
once you reach the joint distend with 5 mL of lfuid and a stab incision #11 is made through **m. intertransversarii** and joint capsule
128
how much of pressure is maintained in the APJ according to Tucker et al 2021?
60 mmHg
129
what is the ideal candidate for arthroscopy of APJ?
horses that show signs of neck pain without evidence of spinal cord compression and with minimal additional cervical pathology
130
are articular loose bodies accessible in C7/T1?
No, C7/T1 APJs were considered surgically inaccessible
131
which articular process is more challenging?
caudodorsal recess is more challenging owing the narrow and oblique angle joint space
132
3-year-old Warmblood mare was presented with spinal ataxia of 3 months’ duration METER RADIO DO CASE REPORT Brunisholz
133
Subtotal dorsal decompression laminectomy of the cervical vertebrae complications postoperatively
significant postop complications: which include **articular facet fractures**, **compressive hematomas**, and **suppurative meningitis**
134
describe dorsal laminectomy
LR or sternal
30 cm inciison caudal to occipital protuberance
the nuchal fat is divided, and the funicular portion of the nuchal ligament is incised, bluntly separated along the midline and
then retracted laterally
**semispinalis capitis **and **rectus capitis dorsalis** muscles are divided along the midline and folded back from the bone using periosteal elevators.
The** dorsal atlantoaxial ligament **and **interspinous ligament** are partially and sharply separated from their attachments to the dorsal arch of the atlas with scissors. A high-speed burr is used to remove an oval shape from the caudal two-thirds of the** dorsal arch of the atlas**. As soon as the inner cortical layer of bone becomes apparent, r**everse-cutting
rongeurs** can be used to **remove the dorsal arch** while protecting the cord This should relieve spinal cord compression and maintain the range of motion of the **atlantoaxial articulation.**
Part of the dorsal arch (1–1.5 cm) is left in place cranially
as well as part of the atlantoaxial membrane. The
dural sac protrudes into the laminectomy defect, but durotomy
is not necessary. A 5 mm thick autogenous fat graft is
harvested from the adjacent nuchal fat and placed in the
bony defect to prevent laminectomy scar formation. The
surgical wound is closed in four layers, and a stent is placed
over the skin sutures. Neurological signs are slow to
improve.
135
what happened?
Figure 34.4 Anatomic specimen demonstrating
dorsal laminectomy of the atlas. Cranial is to the
left. A high-speed
burr is used to remove an oval
shape from the caudal two-thirds
of the dorsal
arch of the atlas (white arrows). The dorsal
atlantoaxial ligament (AtAxL) and interspinous
ligament are separated from their attachments
to the dorsal arch of the atlas. SC: spinal cord;
DS: dural sac just dorsal to the defect. The dural
sac and the atlantoaxial membrane have been
removed at the level of the atlantoaxial joint.
136
137
How would you manage a horse referred to with acute fracture of cervical and minimal neuro signs
Horses with minimally displaced fractures, with no or minimal
neurologic signs, can be managed medically with a **NSAID
(phenylbutazone: 4.4 mg/kg IV s.i.d.)**, corticosteroids (**dexamethasone:
0.1 mg/kg IV q12h)** and **DMSO (1 g/kg q24h)** in an
intravenous perfusion of lacted Ringers solution. Corticoids
are helpful to reduce oedema but should be used with care and
only for a short period in adult horses as they may induce laminitis and, if surgery is elected, may impact bone and soft tissue healing. The risk of further displacement of the fracture, which may occur during intense neck movement when the horse
stands up after lying down, can be reduced by keeping the
horse in a sling. The above treatment protocol can be continued
and adapted according to the clinical signs.
138
Figure 34.12 (a) Custom-made
V-shaped block used to stabilize the neck in a strictly vertical position and hold a radiographic cassette. (b) Horse positioned for surgery: neck in the block (white arrows), head square and secured. Skin staples (black arrows) mark the affected vertebra. A mobile X-ray machine (large white arrow) is mounted on an arm at an appropriate fixed angle to ensure
accurate intra-operative
imaging.
139
Figure 34.13 Instruments for efficient exposure of the ventral
aspect of the vertebrae. Left to right: curved osteotomes,
self-retaining
Inge retractors (x2) and Beckman–Adson retractor.
Upper left: bone gouge forceps (rougeurs
140
Figure 34.19 Anatomic specimen demonstrating dorsal laminectomy. Cranial is to the left. (a) A peripherical rectangular channel is burred,
outlining the lamina to be removed from each vertebra. Care is taken not to damage the spinal cord when reaching the thin inner cortex.
(b) The free lamina of the cranial and the caudal vertebra are removed avoiding excessive lateral excavation. Following decompression, a fat
graft is placed in the defect, covering the dural sac (the latter has been removed in the photograph). SC: spinal cord.
141
Occipitoatlantoaxial Malformation (OAAM) occurs typically in which breed?
Arabian horses, it is inherited in an autosomal recessive manner
142
Occipitoatlantoaxial Malformation (OAAM) has sex predilection?
no
143
Occipitoatlantoaxial Malformation (OAAM) occurs in which phase of developmental?
developmental error occurs during embryogenesis, before the end of the sixth week of gestation
144
OAAM consistis in what?
consist of an asymmetric fusion of the atlas to the occiput and frequently involves ventral luxation of the dens of the axis
145
diagnosis
Lateromedial radiographic view of a 3.5-year-old Swiss Warmblood mare with occipitoatlantoaxial malformation
146
OAA clinical signs
obvious at birth or detected within the first few weeks up to 3 years old
Affected animals demonstrate marked weakness and ataxia when walking and may have an extended head and neck position. A clicking sound may be elicited by manipulation of the head, resulting from the dens slipping under the body of the atlas
147
Pathologic changes of the nervous system associated with OAAM
1) dorsoventral flattening of the medulla oblongata
2) dorsoventral flatening of the cranial cervical spinal cord
148
what is hemivertebrae?
Hemivertebrae are wedge-shaped vertebral bodies in which the vertebral body apex may point dorsally, ventrally, or medially, resulting in kyphosis, lordosis, or scoliosis
149
what happened?
Figure 53-44. Laterolateral radiographic view of the cervical spine with a distal femoral locking compression plate applied to the ventral aspect of C1 and C2 of a horse, which was presented for an atlantoaxial subluxation. The implant pulled out of C2 because the screws inserted were too short (arrows).
150
What type of plate is recommended for fracture fixation in a single vertebra fracture?
Either an LCP or a DCP
151
What is the aim of treatment for fractures involving two vertebrae?
Fusion of the fractured vertebrae and possibly the next adjacent caudal vertebra
152
What is the preferred treatment approach for articular process fractures?
Intervertebral fusion with plates applied to the ventral aspect of the involved vertebrae
153
How to prepare for the surgery?
154
What are the pathologies of the articular process joints?
1. OCD
2. Fracture
3. OA
155
Schulze et al 2021 Vs Arthroscopic removal of osteochondral fragments in cervical articular process joints in 3 horses is also presented but instead of US she uses:
A. CT
B. constrat myelogram
C. Radiographs
D. Just US
C. Radiographs
right-45º-dorsal left ventral oblique
156
What are the clinical signs of the horses presented for percutaneous full endoscopic foraminotomy for treatment of cervical spinal nerve compression in horses using uniportal approach?
-lameness
-stumbling
-local pain
-unrideable
- restricted neck movement
-reduced protraction
symptoms may vary with neck position
156
# cer
157
what is the goal of foraminotomy?
To decompress cervical spinal nerves. Bone specimen(A) showing the middle third of the ventralaspect of the cranial articular process (reddashed circle), representing the optimal region of the needle position.
158
FIGURE 5 Bone specimen(A) showing the middle third of the ventralaspect of the cranial articular process (reddashed circle), representing the optimalregion of the needle position. Cadavercervical spine (B) showing the needlepositioning. The yellow needle representsthe optimal needle position. Note the flowof the cerebral spine fluid from the greenneedle hub (indicating an iatrogenic injuryof the spinal canal), which is positionedonly a couple of millimetres ventral to theyellow. (C) Transverse CT image ofanother cadaver showing the optimal(A) and suboptimal (B) needle position.
159
FIGURE 1 Endoscope structure
including working channel, optical and
light system, and irrigation canal.
160
FIGURE 1 Endoscope structure
including working channel, optical and
light system, and irrigation canal.
161
Under fluoroscopy guidance a K wire 0.5 is placed through a 20 G 20 cm spinal needle. What is the size of the endoscope?
Dilator 5.9 mm
Endoscope 6.9 mm, diameter, 207 mm length and 25º angle of vision
162
describe the foraminotomy surgical procedure
******Spinal needle** used to access the operation site
**K-wire** introduced through the needle followed** by a dilator** (5.9 mm diameter) placed over the k-wire, and then a **working sleeve **placed** over the dilator,** through which the** endoscop**e can be inserted.
**207 mm long endosope used in this study has an outer diameterof 6.9 mm** and consists of an eccentrically located lens with a viewing direction of 25, a 4.1 mm diameter working channel and twoirrigation channels for in- and outflow
A range of different instruments is available with outside diameters from 2 to 4 mm topass through the working channel, such as a micro-rongeur (290 mmlength, 2.5 mm diameter), a micro-punch (290 mm length, 2.5 mmdiameter), and a micro-bone punch (290 mm length, 2.5 mm diameter).
**Electrocautery was used to minimise haemorrhag**e and allow for a clear viewthrough the endoscope.
After the AP bone was freed of the surrounding muscle and fascial attachments **the sleeve was rotated 180**, shielding the IVF soft tissues from the working instruments, thereby minimising the risk of iatrogenic injury to the nerve and adjacent structures.
Different burrs connected with a Combi drive were used for drilling. Then aprotected burr was advanced (Figure 3C).
A **pre-drilling fluoroscopic projection** was made to ensure the correct positioning of the burr.
**Drilling** was continued and **controlled fluoroscopically** until the interface between the trabecular bone and the medial aspect of the medial (inner)cortex of the cranial AP was exposed and removed by a micro-punch,until the spinal canal and nerve root were visualised
163
What is the plan for postop recovery foraminotomy?
2 d box rest, 5 days walk, 3 w lunging, 2 w draw reins lunge, normal riding
164
What are the surgical techniques in the cervical
1. Ventral interbody fusion with kerf cut cylinders (KCC)
2. Dorsallaminectomy - for wobblers
3. LCP plate
4. Polyaxial pedicle screw and rod constructs and ventrally placed locking compression
5) 3D printed cervical plate and spacer
165
Where are the most common lesions for OA and CVM?
Lindgren et al 2021 90% of the lesions are caudal to C5, so C6-C7 and C5-C7
Jan Hein majority are caudal to C6-T2
166
Cervical vertebra stenosis has to go accordingly to a Mayhew grading neurologic grading. Describe the grading
167
What is CVSM
Cervical Vertebral stenotic myelopathy is a developmental disorder characterized by deformation of cervical vertebral leading to stenosis of vertebral canal and spinal cord compression
167
which breed are predisposed to CVSM?
Thoroughbreds, Quarter Horses, and Warmblood breeds
168
what are the two forms of CVSM described?
*Type 1 CVSM =vertebral malformation & malarticulation = dynamic instability of vertebralcanal (YOUNG horses)
*Type 2 CVSM =cervical osteoarthopathy = static cord compression (MATURE - image)
169
Onset age for CVSM
The age of onset is typically 6 months to 3 years
although mature horses (4–20 years) are identified with acute onset of spinal cord compression because of cervical stenosis from arthropathy
170
typical clinical signs CVSM
demonstrate upper motor neuron deficits to all four limbs, characterized by symmetric weakness, ataxia, and spasticity
At a walk, weakness is manifested by stumbling and toe dragging; horses with prolonged clinical signs of CVSM may have hooves or shoes that are chipped, worn
171
The CVSM is more in females or males?
Males
172
How do you diagnosee CVSM?
accurate history,
thorough physical
neurologic examinations,
radiographic evaluation of the cervical vertebrae,
CT or MRI (CT with myelography is the most useful)
Cerebrospinal fluid analysis (to differentiate from equine protozoal myeloencephalitis
173
differential diagnosis of CVSM
equine protozoal myeloencephalitis (EPM), equine degenerative myeloencephalopathy (EDM), equine herpesvirus myelitis, OAAM, spinal cord trauma, vertebral fracture, tumors including melanoma, and vertebral abscess
174
The five radiographic features characteristic for deformations of the cervical vertebrae in horses with CVSM
1. subluxation of adjacent vertebrae,
2. flare of the caudal epiphysis of the vertebral body,
3. extension of the dorsal laminae,
4. abnormal ossification of the articular processes,
5. osteoarthritis of the articular facets --> ++ common dx in the caudal cervical vertebrae
175
what is the intravertebral sagittal ratio measurement?
intravertebral sagittal ratio measurement was developed to objectively determine the cervical vertebral sagittal diameter in horses
176
how do you calculate the minimum sagittal diameter?
vertebral body width?
**MSD:** by determining the narrowest diameter measured from the dorsal aspect of the vertebral body to the ventral border of the dorsal laminae at any point along the vertebral canal (b)
**vertebral body width:** vertebral body width is measured perpendicular to the vertebral canal at the widest point of the cranial aspect of the vertebral body (a)
The **sagittal ratio ** is calculated by dividing the MSD of the vertebral canal by the maximal height of the vertebral body.
**MSD ratio** (c) is determined by measuring the shortest distance from the caudal dorsal lamina of the more cranial vertebra to the dorsal aspect of the cranial physis scar of the next caudal vertebra, and the shortest distance from the dorsal aspect of the caudal epiphysis of the more cranial vertebra to the cranial dorsal lamina of the next caudal vertebra; then the smallest value is used.
177
Figure 53-35. (A) Illustration showing the intra- and intervertebral sagittal ratio measurement. a, Longest distance of the cranial aspect of the vertebral body, measured perpendicular to the vertebral canal; b, shortest distance measured from the dorsal aspect of the vertebral body to the ventral border of the dorsal laminae; c, shortest distance from the dorsal aspect of the physeal scar of the more cranial vertebra to the cranial dorsal lamina of the more caudal vertebra; c1, shortest distance from the caudal dorsal lamina of the more cranial vertebra to the dorsal aspect of the cranial physeal scar of the more caudal vertebra. (B) Laterolateral radiographic view showing lines of measurement for determination of the intra- and intervertebral sagittal ratio.
178
specificity and sensitivity of radiography for detection of CVSM
specificity 50% and sensitivity 70% of radiography for detection of CVSM
179
Figure 53-36. (A) Laterolateral myelographic view for the measurement of the dorsal myelographic column (DMC). A diagnosis of spinal cord compression is made when there is a 50% or greater decrease in the sagittal diameter of the dorsal column; the intervertebral DMC is compared with the intravertebral DMC of the next cranial site. (B) Laterolateral myelographic view for the measurement of the entire dural diameter (DD). Spinal cord compression is suspected when there is a 20% height reduction of the DD at the intervertebral site compared to the intravertebral site.
180
Figure 53-37. Laterolateral myelographic view showing a compression (arrow) at the articulation of C5 to C6. (Courtesy F. Rossignol, Paris, France.)
181
Spinal cord compression can be evaluated myelographically using three criteria based on reduced height of the myelographic column (Figures 53-36 and 53-37): (1) the entire dural diameter (DD)—the DD reduction rule implies that compression can be suspected when the minimal intervertebral DD is at least 20% reduced compared to the maximal intravertebral DD; (2) the dorsal myelographic column (DMC)—the DMC rule diagnosis spinal cord compression when there is as 50% or greater height reduction of the intervertebral DMC compared to the maximal intravertebral DMC at the level of the vertebral body just cranial to it; and (3) the 2-mm rule—this rule indicates compression when the DMC is less than 2 mm in height
182
An intravertebral ratio of less than _______ was reported to increase the likelihood of diagnosis of cervical cord compression by myelography at the site
An intravertebral ratio of less than 0.5 was reported to increase the likelihood of diagnosis of cervical cord compression by myelography at the site
183
CT provides information about the spinal cord?
No, Although spinal cord compression can be identified with CT, it provides no information regarding the integrity of the spinal cord
184
What horses are candidates to surgery?
Not all horses are candidates, horse NOT RECUMBENT and is importante accurate diagnoss like CT which is the gold standard
185
For which condition is a horse considered an ideal patient for surgery?
Young horses showing mild neurologic signs due to CVSM
186
What questions have to be answered before surgery?
Nº site of cord compression
Cheter the cord compression is static or dynamic
Severity of clinical signs
Duration of clinical signs
Temperament of the horse and age
187
hat is the reported agreement percentage between myelography findings and necropsy results?
50-80%
188
Which criteria is NOT recommended for evaluating cord compression myelographically due to unacceptable specificity?
2mm rule – compression when DMC is less than 2mm in height
189
What does myelography help differentiate in spinal cord compression?
Dynamic (type 1) vs. static (type 2) compression
190
How many sites of compression are preferable for a better prognosis in spinal cord compression?
Less than 3
191
Which type of spinal cord lesions often have a better prognosis according to the text?
Dynamic lesions (most commonly at C3 to C4)
192
Which approach is used for surgery on the caudal cervical vertebrae?
DR with extended neck
Muscles that insert on vertebrae must be retracted abaxially and acess to the ventral aspect
Carefull to avoid arteries and veins
Forelimbs tied flexed and pulled somewhat caudally to allow acessto the caudal portion of the neck by imaging (C-arm) and surgeon
193
What are the most common types of developmental vertebral anomalies?
1) cervical vertebral stenotic myelopathy (CVSM) Wobller syndrome
2) Occipitoatlantoaxial malformation (OAAM)
194
What is required for vertebral interbody fusion?
The Kerf-Cut cylinder (KCC) or a LCP
195
Describe the next step once the ventral surface of the intervertebral canal is exposed for kerf cut
After exposing the ventral surfaces of the affected vertebrae, the alignment is corrected and maintained with bone-holding forceps.
A **25mm diameter drill guide** is placed on the ventral surface of the** intervertebral oint space **using radiographic control.
The aim is to equally best ride the articulation at the **depth of 25 mm.**
The **drilling depth should be 25 to 30 mm.**
A **shelf of 10 mm** of bone should be leftbetween the drill and the bottom of the spinal canal
196
**How deep should the drilling be according to the surgical guidelines?**
25 to 30 mm
197
What is the minimum amount of bone that should be left between the drill and the bottom of the spinal canal?
10 mm
198
Figure 53-42. (A) Illustration showing positioning of the K-wire and the large centering pin. (B) Illustration showing the K-wire, the large centering pin, and the four-pronged drill guide hammered into the vertebrae. (C) Illustration of the the drill bit. (D) Illustration of the Kerf cutter. (E) Illustration of the partially threaded Kerf-cut cylinder. (F) Illustration of the fully threaded Kerf-cut cylinder.
199
Figure 53-42. (A) Illustration showing positioning of the K-wire and the large centering pin. (B) Illustration showing the K-wire, the large centering pin, and the four-pronged drill guide hammered into the vertebrae. (C) Illustration of the the drill bit. (D) Illustration of the Kerf cutter. (E) Illustration of the partially threaded Kerf-cut cylinder. (F) Illustration of the fully threaded Kerf-cut cylinder.
200
201
what is this procedure?
Tap procedure during kerf cut cylinder insertion
202
Once you did the drilling of 25-30 mm deep n the ventral surface of the intervertebral joint was is the next step?
Once the correct depth has been reached, the drill guide is removed and the implant site is widened by a number 1 Kerf-Cutter and later with a number 2.
The implant is inserted until firm resistance is encountered.
Bone graft is collected from the bony cylinder removed during drilling from the ventral spine
The bone graft is impacted firmly inside the hollow implant.
cancellous bone grafts, sampled from the sternebrae, or calcium phosphate are placed inside the intervertebral disk space to stimulate their fusion within this space.
203
What was the overall success rate mentioned by Auer for surgical intervention in cervical vertebral malformation (CVM)?
Approximately 60%
204
What is the after care required after kerf cut cylinder?
AB and NSAIDs 3 days
Postoperative radiographs immediately postop and 2+ months post surtery
205
what is the rest required following surgery
2 months stall rest, 1 month hand walking, 2 m progressive
206
Why is a partially threaded titanium KCC preferred over a fully threaded option?
It is less likely to cross-thread and drill a separate channel
207
What is a limitation of the KCC for cervical stabilization?
It relies entirely on compression but offers no stability in tension
208
How does the technique involving the KCC promote faster fusion?
By leaving an isthmus bone in the center of the cylinder
209
What is the new technique described useful for the type of static compression (Type 2) ?
Percutaneous full endoscopic foraminotomy for treatment of cervical spinal nerve compression in horses Jan Hein 2021
210
What is the state of art for cervical stabilization?
LCP plate
211
What is the surgical approach once you reach the vertebra?
Ventral midline approach (same as KCC)
Top L– Prep bone: ventral spinous process of affected vertebrae flattened withcurved osteotome + bone rongeur
Lmiddle – Disc material removed, multiple parallel drill lines (5.5mm drill bit) under rx guidance Bottom
L – expose ventral surface affected vertebrae, alignment is corrected andmaintained with bone holding forceps
212
What is the surgical approach once you placed the holding forceps?
Top R– appropriately sized plate applied – SMALL or BROAD 3.5/4.0 or 4.5/5.0mm LCP used MINIMALPLATE BENDING NEEDED
Rmiddle – 1 cortex screw inserted In EACH vertebra in LOAD position – correct length determined with fluoroscopic guidance (DO NOT DAMAGE CORD)
BottomR – Remaining holes – locking head screws Similar closure to KCC
Postop management SAME as KCC implant
213
LCP placement with good results. What is the surgical technique?
The ventral spine of the CV was flattened using an **oscillating saw or osteotome.**
The** intervertebral disc **was partially **removed** using a **Ruskin Rongeur**, spoon curette or 3.2 to 4.5 mm drills depending on surgeon’s preference.
A **stainless-steel LCP** was applied to the **ventral surface** of the affected vertebrae under fluoroscopic control. Length and type of the plate depended on the location and extent of the cervical instability.
The plate was carefully contoured to the surface of the vertebrae.
Whenever possible, **5.0-mm locking head screws** were inserted into the plate holes; **4.5- or 5.5-mm cortical screws ** were only used if angulation of a screw wasrequired or the threaded part of the combi-hole was damaged. All plate holes were filled with screws
214
what is this tex?
Titanium polyaxial pedicle screw kit, consisting of pedicle screws, connecting rod and set screws. (A) Porous metal interbodyfusion device measuring 15 x 15 x 35 mm. (B) Drawing of polyaxial pedicle screw and rod construct with screws placed on right and leftside of ventral keel and placement of a porous metal interbody fusion device in situ. The connecting rod is placed within the tulip heads ofthe pedicle screws. Set screws are then placed on top of the connecting rods and locked in place using a torque-limited driver, resulting inangulation capacity of 50 degrees of the shaft of each pedicle screw.
215
What are the advantages of LCP
Good to excelent results
Effectively provides compression
Easily accessible Biomechanical superior
216
Disadvantages of LCP
The flexion of the neck predisposes the fixation to failure by causing screw retraction from the bone
- Permanent cyclic stress to te plate might contribute to breaking of the plate and screws
- Pronounced contouring of the plateweakens it and makes breakage more likely
- Application of the plate to the ventral aspect --> violates the principle of applying the plate to the tension side of a bone
-New bone formation can be seen on radio in ventral aspect 2 mont after -> stable callus at 10 months
217
What was the size and type of plate used in Schulze 2019 VS?
Six hole 4.5 mm T-locking compression plate
218
describe which tx this instruments are used?
Pedicle screw and Rod constructs was state of art in lumbar spine fusion of humans.
219
What are the surgical landmarks for pedicle screws?
Same as for Kurf and LCP ventral acess in DR with extended neck
220
describe the surgical placement of polyaxial titanium self-tapping pedicle
Needle (18-gauge) was placed into the disc space intended for fusion
**Threaded K-wire **was placed in the **ventral body of the cranial vertebra** at the most cranial extent of the intended **intervertebral defect, approximately 8mm cranial** to the cranial end plate in order to centre the defect in the disk, determined fluoroscopically.
**High-speed surgical drill** and **6-mm cylindrical diamond** burr were used to **create a rectangular intervertebral defect **in the intervertebral space. Approximately **5 mm of the cranial and caudal adjacent vertebral end plates** were removed under saline irrigation to create a centrally located defect approximately 3**5-mm long × 15-mm wide × 15-mm deep to accommodate placement of the metal IFD** (Figure 1).
Using an i**nserter tool and mallet**, the IFD was placed in the defect and placement confirmed fluoroscopically.
Next, four **4.5-mm diameter × 30-mm long polyaxial titanium self-tapping pedicle screws **with dual core bodies were placed in the **cranial and caudal vertebrae**,1-cm from the defect on either side of midline and 1-cm cranial or caudal to the edge of the disk space.
Two **5.5-mm diameter precut titanium rods** approximately **80-mm long** were placed through the heads of the pedicle screws, spanning the disk on both sides of midline.
A pedicle screw compression tool was applied to reduce dead space on the cranialand caudal edges of the IFD.
Set screws were inserted into the **tulip heads** of the **pedicle screws to lock the rods in place.**
Position was confirmed fluoroscopically intraoperatively prior to closure.
221
WHERE DO YOU PLACE 2 POLYAXIALPEDICLE SCREWS?
Cranial vertebra 1 cm cranial to the defect 1 to the L and1 to the R of midline
Caudal vertebra 1 cm caudal to the ventral edge of thedisk space - 1 to the L and 1 to the R of midline
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Two 5.5-mm diameter precut titanium rods (orange) were placed through the heads ofthe pedicle screws pediclescrew compression tool (blue)wasmoderately applied to the screws R and L of midline to minimize any dead spaceon the CR or CD edges of the IFD (blue) Set screws were inserted into the tulip heads (green arrow) of the pedicle screws to lock the rods in place with compression applied acrossthe IFD and disk space
