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ECVS 24th Symposium July 4th 2015 - Berlin, Germany, Europe
Cervical Arthroplasty:
A Non-Fusion Technique for Disc Associa...
ECVS Surgery Symposium
July 2-4, 2015
Disclosure
 I designed and developed the medical device included
in this presentati...
Goals:
Preserve motion after neural
decompression while providing
distraction and stability
Potentials:
May prevent “domin...
Phase 1.
DESIGN
 Madison, WI 2003
Phase 2.
IN VITRO BIOMECHANICAL STUDY
 Adamo, Kobayashi et al. Vet Surgery 2007
4 Gr...
 Phase 3.
Pilot clinical study in 2 client-owned dogs with
DAWS
Titanium alloy
 Results
 Follow up to 3½ years post-op
...
Cervical Disc Arthroplasty using
the Adamo Spinal Disc™ in 33 dogs
affected by Disc Associated
Wobbler Syndrome
at Single ...
Study Authors
 F Adamo, DECVN
 East Bay Vet Specialists – CA
 R Da Costa, DACVIM (Neurology)
 The Ohio State Universit...
To evaluate:
a) the immediate post-operative recovery
b) the short-, intermediate- and long term follow-up
of dogs with on...
Material & Methods
 Implant: Similar to that in the pilot study but with several modifications
1st generation
- Ball Tita...
Spinal Disc 2nd & 3rd Gen.
 Internal surfaces
 Convexity is PEEK
(PolyEther Ether Ketone)
 Thermoplastic polymer
 Decr...
 External surface
 Convex
 To resemble natural
concavity of vertebral end
plates
Spinal Disc 2nd & 3rd Gen.
 Concentri...
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 pi...
Sizing Probes
• Resemble at each end the shape of either
mthe S, M, or W disc size
•To probe/test the disc space during
nb...
Small burr
• To clean end-plates and begin
creating concavity
Large burr
• matches the external disc
convexity
• To facili...
20 degree angle attachment for the Surgairtome
 To facilitate working at an angle parallel to the disc
space during burri...
Caspar Cervical Distractor
• To maintain vertebral distraction during implantation
• To allow visualization through the di...
Disc space prepared for the implant
Vertebral end plate
Dorsal Long. Lig.
 Sample population:
 First 33 clients-owned dogs w/ over 2
mo. history of DAWS
 Diagnosed by MRI or CT myelo
 Weight o...
 Total = 50 disc sites treated
 Single, two and three level lesions
 Neurological Assessment
 Grade 0 to 6
 De Decker...
 Optimal
 Implant well centered in
the disc space on lateral
& VD views
 Sub-optimal
 Off midline on VD
 Inadequate
...
 Relative Distraction ratio (RDR):
 Ratio between post-op and pre-op
width at the treated space
 Adequate / Ideal*
 RD...
Ventro-flexion
Dorsi-flexion
Neutral
Mobility
 Distance between dorsal and ventral
edge of the 2 faces of the implant in
...
 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 Weimer...
 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)
...
Inadequate position
Immediate Post-op Radiographs
 Implant position:
• Optimal (42 sites)
• Sub-optimal (7 sites)
• Off m...
Caudal subsidence
 Distraction:
• Over-distraction (15 sites)
• Mostly with 1st generation (thicker)
implant
• Adequate d...
Distraction:
 Minor Subsidence: Distraction lost
compared to immediate post-op, but maintained
when compared to pre-op
 ...
 Mobility
 Decreased or not detectable over time in the
majority of patients.
 Maintained at 2 wks post-op in 88% of 24...
 3 dogs: 7-24 mo post-op
 Osteophites or Heterotopic Ossification.
 Didn’t affect the clinical status
 1st and 2nd gen...
 Post-op recovery time
 Immediate in all dogs
 Neurological status unchanged compared
to pre-op status in all dogs
 Po...
Follow-up: Mean 24 mo, (range 2 wks - 42 mo)
 21 dogs still alive
 12 dogs deceased
 9 for non-neurological diseases
 ...
Complications and
Poor Outcome
Complications
 Vertebral fissure fracture during distraction: 2 dogs
 Improper Caspar pins placement
 +/- excessive dis...
Complications
 Vertebral Axial Compression fracture: 1 dog
 Nikkie
 Sheltie Mix, F, 12.4 y old,
 29 lb = 12.2 kg
Histo...
Poor Outcome
2 dogs
 Chow Mix, F, 13.5 y old
 Doby, M, 12 y old
History
 8-14 months progressive non ambulatory tetrapa...
Advantages of CDA
 Less invasive than traditional surgeries
 Rapid post-surgical recovery
 Can be performed on a out-pa...
 Immediate relief of radicular pain
and vascular compression at the
intervertebral foramina
 Enable MRI re-assessment
 ...
Disadvantages – Limitations
 Concurrent Dorsal spinal compression
 The possible decrease of distraction may
exacerbate t...
Conclusions
 CDA using this prosthesis appears to be safe
and effective
 Suitable for medium and large breed dogs
 Rapi...
Currently in use
4th Generation Spinal Disc™
 Thinner implants: 8.3mm
  To avoid over-distraction
  To allow implant ...
 Two External Layers of Coating:
 Commercial Pure Titanium (CPTi):
 To create sponge porosity
 HA
 To promote bone/im...
3 mo. post-op
4th practical CDA Course
 November 5, 2015
 Las Vegas, Oquendo Center
Program: Wobblersyndrome.com
Event C...
Questions
Contact:
Filippo Adamo, DVM, DECVN
East Bay Veterinary Specialists
Walnut Creek – California
Phone: 925.937.5000...
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Cervical Disc Arthroplasty - a non fusion technique for Disc Associated Wobbler Syndrome in dogs - power point - august, 2015 - berlin - ecvs

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Cervical Disc Arthroplasty in dog with Disc Associated Wobbler Syndrome - A non fusion surgical technique.

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Cervical Disc Arthroplasty - a non fusion technique for Disc Associated Wobbler Syndrome in dogs - power point - august, 2015 - berlin - ecvs

  1. 1. 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
  2. 2. 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
  3. 3. 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
  4. 4. 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 able to mimic the behavior of intact spine compared with ventral slot and Pin+PMMA groups. History
  5. 5.  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
  6. 6. 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
  7. 7. 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
  8. 8. To evaluate: a) the immediate post-operative recovery b) the short-, intermediate- and long term follow-up of dogs with one level and multi-level disc- associated-wobbler-syndrome (DAWS) treated with cervical disc arthroplasty (CDA). Objectives
  9. 9. 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
  10. 10. 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
  11. 11.  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
  12. 12. Implant Design Modification  7 different disc sizes  Set of dedicated tools
  13. 13. Threaded pins • to hold the assembled prosthesis Dedicated tools
  14. 14.  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
  15. 15. 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
  16. 16. 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
  17. 17. 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
  18. 18. Caspar Cervical Distractor • To maintain vertebral distraction during implantation • To allow visualization through the disc space to the dorsal longitudinal ligament Dedicated tools
  19. 19. Disc space prepared for the implant Vertebral end plate Dorsal Long. Lig.
  20. 20.  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
  21. 21.  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 C3 C4 C5 C6 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
  22. 22.  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
  23. 23.  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 C7 C6 C5 Pre-op Post-op
  24. 24. 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
  25. 25.  2 years post-op when possible  As needed, in the event of recurrence of clinical signs MRI re-evaluation
  26. 26. Results
  27. 27.  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
  28. 28.  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 C6 C7 C3 C4 C5 C6 C3 C4 C5 C6
  29. 29. 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
  30. 30. Caudal subsidence  Distraction: • Over-distraction (15 sites) • Mostly with 1st generation (thicker) implant • Adequate distraction (34 sites) • Mostly with 2nd & 3rd generation (thinner) implant • Under-distraction: (1 site) • Improper technique  Excessive burring of caudal endplate – immediate subsidence Immediate Post-op Radiographs
  31. 31. Distraction:  Minor Subsidence: Distraction lost compared to immediate post-op, but maintained when compared to pre-op  All sites  More pronounced with 1st generation (thicker) implant  Less pronounced with 2nd and 3rd generation (thinner) implant  Severe Subsidence Distraction lost compared to pre-op  7/50 sites (14%) Serial Radiographic Assessment
  32. 32.  Mobility  Decreased or not detectable over time in the majority of patients.  Maintained at 2 wks post-op in 88% of 24 dogs examined  Maintained at 6 mo post-op in 23% of 14 dogs examined  Maintained at 9 mo post op in one dog  Maintained at 3 years post-op in one dog ♬ In 7 dogs where dynamic study was performed immediately after surgery: mobility although expected was not detectable in 5 out of 10 treated spaces in 3 dogs was later detectable on the serial follow-ups.  No Implant migration  No Implant infection Serial Radiographic Assessment Ventro-flexion Dorsi-flexion
  33. 33.  3 dogs: 7-24 mo post-op  Osteophites or Heterotopic Ossification.  Didn’t affect the clinical status  1st and 2nd generation implant  3 dogs: 24-36 mo post-op  No signs of disc degeneration or compression at treated and adjacent sites  1 dog: 6 wks post-op  Spinal compression secondary to immediate subsidence  Improper technique  Improved with single dorsal decompression MRI Re-assessment: 7 dogs C3-C4 C5-C6 C5 C6 C7 C5-C6 6 wks post – op C6 C7*  In all dogs the implant didn’t affect the spinal cord visibility
  34. 34.  Post-op recovery time  Immediate in all dogs  Neurological status unchanged compared to pre-op status in all dogs  Post-op hospitalization time *  5 dogs: Discharged same day  26 dogs: 1- 3 days  2 dogs: 4 - 5 days  Based on the severity of the neurological status pre-surgery Clinical Assessment
  35. 35. Follow-up: Mean 24 mo, (range 2 wks - 42 mo)  21 dogs still alive  12 dogs deceased  9 for non-neurological diseases  3 euthanasia: insufficient improvement or complications Patient Outcome  91% have shown improvement of at least 1+ neurological grade  Satisfactory to Excellent: 30 dogs  Unsatisfactory: 1 dog  Poor: 2 dogs  Better Outcome: mild and short duration of signs on presentation  Worse Outcome: chronic non-ambulatory tetraparesis + extensor rigidity of front legs not resolving under general anesthesia  No Domino lesions during the observation period
  36. 36. Complications and Poor Outcome
  37. 37. Complications  Vertebral fissure fracture during distraction: 2 dogs  Improper Caspar pins placement  +/- excessive distraction with Caspar Distractor   Did not affect the outcome  Immediate subsidence: 1 dog  Improper technique: over-burring.  Surgical revision with dorsal laminectomy   Regained improvement  Subsidence: 7/50 disc spaces  Too thick and too narrow discs   Except for 1 dog, did not affect the outcome Improper technique
  38. 38. Complications  Vertebral Axial Compression fracture: 1 dog  Nikkie  Sheltie Mix, F, 12.4 y old,  29 lb = 12.2 kg History: 4 years ambulatory ataxia, 6 month prior to referral non ambulatory tetraparesis with extensor rigidity all 4 legs, not resolving under anesthesia  Overdistraction  RDR 3.2 (normal > 1.7 and < 2)  2 weeks post-op: Declined to non-ambulatory tetraparesis; Intense cervical pain; Suspected Axial compression fracture C6 + Ventral implant migration Euthanasia - no histopathology 2 weeks post-op Pre-op Immediate Post-op C5 C6 C7 • What went wrong? • Dog’s size too small: 12.2 Kg • Over-distraction  Poor patient selection
  39. 39. Poor Outcome 2 dogs  Chow Mix, F, 13.5 y old  Doby, M, 12 y old History  8-14 months progressive non ambulatory tetraparesis  Severe extensor rigidity all 4 legs, not resolving under anesthesia Outcome:  Dog 1 (Chow): Euthanized 8 mo. after surgery d/t insufficient improvement  Dog 2 (Doby): Neuro score improved only from 6 to 5 • What went wrong? • Neurological signs too severe • Irreversible spinal cord damage  Poor patient selection Pierce Simon
  40. 40. Advantages of CDA  Less invasive than traditional surgeries  Rapid post-surgical recovery  Can be performed on a out-patient basis  Treatment of multiple lesions at adjacent or non-adjacent sites  Prophylactically for “Incipient lesions”  May prevent “Domino lesions”  Spinal cord decompression & “dynamic stabilization” C7 C6 C5
  41. 41.  Immediate relief of radicular pain and vascular compression at the intervertebral foramina  Enable MRI re-assessment  for complications  for long term re-assessment of domino lesions Other Benefits C6 C7*
  42. 42. Disadvantages – Limitations  Concurrent Dorsal spinal compression  The possible decrease of distraction may exacerbate the dorsal compression  It might be necessary to combine CDA with dorsal decompression at the affected site  Not good candidate for CDA  < 23 Kg  Too advanced neurological status  Severe front legs extensor rigidity not resolving under general anesthesia
  43. 43. Conclusions  CDA using this prosthesis appears to be safe and effective  Suitable for medium and large breed dogs  Rapid post-surgical recovery  Ideal for treating multiple levels  Not technically difficult and easy to master  May prevent “Domino Lesions” Case selection, Early Intervention and Correct execution of the surgical technique may be critical factors for the outcome “Case selection is King, …. technique is the Prince”  number 6 of the most commonly cited attributes of a “great” surgeon! Dr. Zelman column
  44. 44. Currently in use 4th Generation Spinal Disc™  Thinner implants: 8.3mm   To avoid over-distraction   To allow implant positioning along the natural angle of disc space  Additional wider & taller sizes  S1, M1, M2, WT1, WT2, + WL1 & WL2   To increase contact surface implant/vertebral endplate  To decrease subsidence
  45. 45.  Two External Layers of Coating:  Commercial Pure Titanium (CPTi):  To create sponge porosity  HA  To promote bone/implant incorporation CPTi + HA Future Directions 5th Generation Spinal Disc™
  46. 46. 3 mo. post-op 4th practical CDA Course  November 5, 2015  Las Vegas, Oquendo Center Program: Wobblersyndrome.com Event Coordinator: Nancy Kroll: nkroll@appliedvt.com
  47. 47. Questions Contact: Filippo Adamo, DVM, DECVN East Bay Veterinary Specialists Walnut Creek – California Phone: 925.937.5000 flppadamo@yahoo.com Wobblersyndrome.com

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