ECVS 24 th Symposium July 4 th 2015 - Berlin, Germany, Europe Cervical Arthroplasty: A Non-Fusion Technique for Disc Associated Wobbler Syndrome in dogs Copy of this presentation: Wobblersyndrome.com under the menu’ tab: “For Veterinarians” Filippo Adamo, DVM, Dipl. ECVN East Bay Veterinary Specialists – Walnut Creek, CA
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ECVS 24th Symposium July 4th 2015 - Berlin, Germany, Europe
Cervical Arthroplasty: A Non-Fusion Technique for Disc Associated
Wobbler Syndrome in dogs
Copy of this presentation: Wobblersyndrome.com
under the menu’ tab: “For Veterinarians”
Filippo Adamo, DVM, Dipl. ECVN East Bay Veterinary Specialists – Walnut Creek, CA
ECVS Surgery Symposium July 2-4, 2015
Disclosure
I designed and developed the medical device included in this presentation.
Currently involved in the distribution trough Applied Veterinary Technology, LLC
Goals:
Preserve motion after neural decompression while providing distraction and stability
Potentials:
May prevent “domino lesions”
Advantages:
Treatment of multiples adjacent & not adjacent spaces
Cervical Disc Arthroplasty (CDA)
Indications:
Disc Associated Wobbler Syndrome
Phase 1.DESIGN
Madison, WI 2003
Phase 2.IN VITRO BIOMECHANICAL STUDY Adamo, Kobayashi et al. Vet Surgery 2007
4 Groups of 6 cervical spines (C5-C6)a) Arthroplasty,
b) Ventral Slot,
c) Pins+PMMA fixation,
d) and normal spine
The artificial disc was better ableto mimic the behavior of intactspine compared with ventral slotand Pin+PMMA groups.
History
Phase 3. Pilot clinical study in 2 client-owned dogs with
DAWS
Titanium alloy
Results Follow up to 3½ years post-op
Both dogs died for unrelated neurological diseases
MRI re-check 2 years post-op No evidence of compression at the treated
and adjacent sites
Conclusions
Cervical arthroplasty was well tolerated and provided excellent outcome in both dogs
Warranted further study: Large number of patients
Longer follow-up
Adamo JAVMA, 239(6), 2011
Cervical Disc Arthroplasty using the Adamo Spinal Disc™ in 33 dogs
affected by Disc Associated Wobbler Syndrome
at Single and Multiple Levels.
In preparation to be Submitted to JAVMA
Study Authors
F Adamo, DECVN
East Bay Vet Specialists – CA
R Da Costa, DACVIM (Neurology)
The Ohio State University – OH
R Kroll, DACVIM (Neurology)
VCA Northwest Vet Specialists – OR
C Giovannella, DACVIM (Neurology)
Gulf Cost Vet Neurology/Neurosurgery – TX
M Podell, DACVIM (Neurology)
Chicago Vet Specialty Group – IL
P Brofman, DACVIM (Neurology)
Veterinary Specialty Care, SC
A Multi-Center Prospective Study
To evaluate:a) the immediate post-operative recoveryb) the short-, intermediate- and long term follow-up
of dogs with one level and multi-level disc-associated-wobbler-syndrome (DAWS) treatedwith cervical disc arthroplasty (CDA).
Objectives
Material & Methods
Implant: Similar to that in the pilot study but with several modifications
1st generation- Ball Titanium
- Dual Ac Etch
2nd generation- Ball in PEEK
- Thinner size
- Dual Ac. Etch
3rd generation- Hydroxyapatite Coating
Calcium Phosphate complex
Porosity
Osteoconduction
8.5 mm
Spinal Disc 2nd & 3rd Gen.
Internal surfaces
Convexity is PEEK
(PolyEther Ether Ketone)
Thermoplastic polymer
Decreases friction
Prevent metallic debris
from a metal to metal joint
Concavity is titanium
Ball and socket
Patent: US 8,496,707 B2
External surface
Convex To resemble natural
concavity of vertebral end plates
Spinal Disc 2nd & 3rd Gen.
Concentric grooves + Central notch To provide “grip” & to prevent implant migration
Implant Design Modification
7 different disc sizes
Set of dedicated tools
Threaded pins
• to hold the assembled prosthesis
Dedicated tools
Thick end
Parallel channels to hold the assembled prosthesis during implantation
Thin end
Slotted to remove the pins after implantation
Barrel Holder – Double function
Dedicated tools
Sizing Probes
• Resemble at each end the shape of either mthe S, M, or W disc size
•To probe/test the disc space during nburring, before final disc implantation
Dedicated tools
Small burr
• To clean end-plates and begin creating concavity
Large burr
• matches the external disc convexity
• To facilitate implant accommodation by the disc space
Large burrSmall burr
Two dedicated burrs
Dedicated tools
20 degree angle attachment for the Surgairtome
To facilitate working at an angle parallel to the disc space during burring
Particularly useful at C6-C7 (and C7-T1 !!)
Dedicated tools
Caspar Cervical Distractor
• To maintain vertebral distraction during implantation
• To allow visualization through the disc space to the dorsal longitudinal ligament
Dedicated tools
Disc space prepared for the implant
Vertebral end plate
Dorsal Long. Lig.
CDA video clip – Implant Placement
Sample population: First 33 clients-owned dogs w/ over 2
mo. history of DAWS
Diagnosed by MRI or CT myelo
Weight over 23 kg, but one (12.2 Kg)
Neurologically and radiologically evaluated
Prior to surgery
Shortly after surgery
within 24 hrs
At 2 wks & 3, 6, 12 & 24 mo. after surgery
Including Criteria
Total = 50 disc sites treated
Single, two and three level lesions
Neurological Assessment
Grade 0 to 6
De Decker, et al. JAVMA 2012; 240:848–857
C3C4
C5C6
Material and Methods
0: No apparent neurological deficits
1: Cervical hyperesthesia w/o deficits
2:: Hind limb ataxia w/o visible paresis
3: Hind limb ataxia with paresis &
no appreciable forelimb ataxia
4:: Ambulatory tetraparesis: broad-
based ataxia hind limbs & choppy
gait forelimbs (“two engine gait”)
5:: Non-ambulatory tetraparesis: able
to stand/walk few steps before collapse
6: Tetraplegia
Optimal
Implant well centered in the disc space on lateral & VD views
Sub-optimal
Off midline on VD
Inadequate
Not seated in center of the disc space on lateral view
Inadequate position
Implant Position
Relative Distraction ratio (RDR): Ratio between post-op and pre-op
width at the treated space
Adequate / Ideal*
RDR > 1.7 and < 2
* Equivalent to a
distraction of 2-3 mm
Under distraction
RDR < 1.7
Over-distraction
RDR > 2
Distraction
C7C6
C5
C7C6
C5
Pre-op
Post-op
Ventro-flexion
Dorsi-flexion
Neutral
Mobility
Distance between dorsal and ventral edge of the 2 faces of the implant in neutral and stressed views
Present
Not detectable
2 years post-op when possible
As needed, in the event of recurrence of clinical signs
MRI re-evaluation
Results
Breeds: 17 Doberman Pinchers (50%)
3 Dalmatians
2 Labrador
2 Bernese Mountain dog
1 Standard Poodle
1 Weimeraner
1 Boxer
1 Greyhound
5 Mix
Sex: 21 M; 12 F
Age: 4 - 13 y; Mean 8.3 y
27% over 10 y old
Single level: 19 dogs
C6-C7 (13 dogs)
C5-C6 (5 dogs)
C3–C4 (1 dog)
Two levels: 10 dogs
C5-C6 & C6-C7 (8 dogs)
C4-C5 & C5-C6 (1 dog)
C3-C4 & C5-C6 (1 dog)
Lesion Localization
Three levels: 3 dogs
C3-C4, C5-C6 & C6-C7 (2 dogs)
C2-C3, C5-C6 & C6-C7 (1 dog)
TOTAL: 50 Spaces treated
C6C7
C3 C4
C5C6
C3C4
C5
C6
Inadequate position
Immediate Post-op Radiographs
Implant position:
• Optimal (42 sites)
• Sub-optimal (7 sites)• Off midline on VD
• Inadequate (1 sites)• Improper technique Excessive burring of caudal
endplate immediate subsidence
Caudal subsidence
Distraction:
• Over-distraction (15 sites)• Mostly with 1st generation (thicker)