This study compared outcomes of 103 patients who received the Bryan artificial cervical disc replacement to 158 patients who received cervical fusion with the Affinity cervical cage system. Patients were examined at 24 months post-operation. The study found higher rates of new osteophyte formation, disc narrowing, and symptomatic adjacent segment disease in patients who received cervical fusion compared to those who received the artificial disc. Specifically, cervical fusion was associated with a 34.6% rate of new radiographic changes compared to 17.5% for artificial discs. The study concludes that preserving motion with an artificial disc may delay or prevent symptomatic adjacent segment disease compared to fusion.

1. ASSESSMENT OF ADJACENT-
SEGMENT DISEASE IN PATIENTS
TREATED WITH CERVICAL FUSION
OR ARTHROPLASTY: A PROSPECTIVE
2-YEAR STUDY
C A S E S T U D Y – C O R Y J E N S E N

2. ADJACENT-SEGMENT DISEASE
Name: Assessment of Adjacent-segment disease in patients
treated with cervical fusion or arthroplasty: a prospective
2-year study
James T. Robertson – Dept. of Neurosurgery, Univ. of Tennessee
Health Science Center
Stephen M. Papadopoulos – Barrow Neurological Inst., Phoenix, AZ
Vincent C. Traynelis – Dept. of Neurosurgery, Univ. of Iowa, Iowa
City, Iowa

3. GOAL/PURPOSE OF STUDY
To compare evidence
of radiologically
documented changes
in adjacent-level
cervical disc disease
after a single level
discectomy and
cervical fusion.

4. STUDY PARAMETERS
The goal of both was to treat the symptoms of DDD in the
Cervical region. The majority of patients were single level
herniated disk or spondylosis (degeneration of body).
Post-Op evidence that they were looking
for:
 New anterior osteophytes
 Enlargement of existing osteophytes
 Narrowing of adjacent disc space >30%

5. HOW WAS THE STUDY (OSTEO)CONDUCTED?
Compared the outcomes of patients using the Affinity
Cervical Cage system, and the Bryan Artificial Cervical
disc.
Examined Radiography for signs of
Adjacent-Level Disk disease
 New anterior osteophyte formation, increased narrowing of an
interspace, new DDD, and calcification of the anterior
longitudinal ligament.

6. HOW WAS THE STUDY (OSTEO)CONDUCTED?
• Affinity Cage study started 2/15/97, and the last
patient was treated 11/15/98.
• The Bryan Study started January 2000, and the last
patient follow up review was June 2004.
• The patients were examined 24 months post-op to
examine results

7. COMPARATIVE X-RAYS
Bryan Artificial Cervical disc. Normal Anterior Single-Level Fusion

8. WHAT DID THEY DO?
Single-level Cervical Discectomy for patients with
single level herniated disk or spondylosis producing
radiculopathy and/or myelopathy from c2-3 to c7-t1.
103 patients used the Bryan Artificial Cervical Disk
 103 patients ranging from 28-97 yrs old. Mean age of 55.9
 61 women 41 men
158 patients used the Affinity Cervical Cage system
 78 men, mean 45.5
 80 women, mean 44

9. AFFINITY CERVICAL CAGE SYSTEM
• The AFFINITY® system uses a simple, easy-to-
implant threaded cage, indicated for single-level
ACDF’s
• Its tapered design provides for optimal restoration
of normal cervical Lordosis

10. BRYAN ARTIFICIAL CERVICAL DISC
• Designed to closely act as a
Vertebral disk
• Not intended for fusion
• Created to keep natural motion
of the spine
Video: https://www.youtube.com/watch?v=8N7PB12Xefg

11. BRYAN ARTIFICIAL CERVICAL DISC

12. COMPARISON/OUTCOME
• Radiological review demonstrated new anterior osteophyte
formation in 17.8% of Affinity cage, and 10.8% of Bryan
Disc.
• Osteophyte enlargement was documented in 8.9% of
Affinity patients, 0% for Bryan System
• Increase in DDD was present in 3.8% of Affinity, 4% Bryan
• New DDD was 1.9% Affinity, 1.3% Bryan
• DDD is based off >30% increase in disc narrowing
• New radiographic changes – 34.6% Affinity, 17.5% Bryan

13. COMPARISON/OUTCOME
• For Affinity 85% of new osteophytes appeared in superior
space, 15% inferior
• For Bryan, only 1 inferior osteophyte was produced
• Symptomatic DDD occurred in 7% using the Affinity system, 0
for Bryan
• 11 Adjacent herniated discs happened with Affinity, 1 for Bryan
System
• Medical treatment was needed in 33% of Affinity cases for
neck, shoulder, and/or arm pain. 1.3% for Bryan.
• For Bryan, only 1 patient required adjacent-level surgery for
symptomatic disc disease.

14. CONCLUSION OF STUDY
• Advocates of procedures in which an anterior discectomy is
followed by a moveable prosthesis has found that preserving
motion will eliminate or diminish the prevalence of adjacent-level
DD.
• This study shows that arthrodesis is very commonly followed by
radiographic changes of adjacent-level disease.
• Based on the radiographic and clinical evidence, it appears that
maintaining motion (Bryan) after a single level anterior
discectomy will delay or prevent symptomatic disc disease, and
will decrease to a significant degree the adjacent-level DD.

15. CONCLUSION OF STUDY
• Also, fusion is associated with a morbidity rate of 6.4%
from non-union. Repeat operation needed.
• Based on the radiographic and clinical evidence, it
appears that maintaining motion (Bryan) after a single
level anterior discectomy will delay or prevent
symptomatic disc disease, and will decrease to a
significant degree the adjacent-level DD.

16. THINGS TO CONSIDER
Disclosure:
 Dr. Robertson is the Medical Director of the Cervical Division of Medtronic
Sofamor Danek.
 Drs. Papadopoulos and Traynelis are Consultants of Medtronic Sofamor
Danek.
Was the Study well done?
 Yes
 Strict qualifications to join the study created an even playing field
 Bryan – Started at 103, ended at 74
 Affinity Cage – Started at 202 ended at 158
 Eliminated for pre-existing conditions and prior spine surgeries