Radiologically documented adjacent-segment degeneration after cervical arthroplasty: characteristics and review of cases.
BACKGROUND
The authors retrospectively studied the incidence and characteristics of radiologically documented adjacent-segment degeneration after single-level diskectomy and subsequent cervical arthroplasty using the Bryan (Medtronic Sofamor Danek; Memphis, TN) disk prosthesis.


METHODS
Seventy-two patients with single-level arthroplasty using the Bryan cervical disk prosthesis were evaluated. Radiological evidence of adjacent-disk disease included new formation or enlargement of anterior osteophyte, new or increasing ALL calcification, or narrowing of disk space documented on serial plain radiographs. We reported the characteristics of adjacent-segment degeneration and reviewed all of the cases.


RESULTS
Among the 72 patients, 9 patients (12.5%) showed radiological evidence of adjacent-segment degeneration. The mean age was 43.3 years old, with a male-female ratio 1:3. The mean follow-up period was 24.2 (12.1-35.9) months. The mean period of onset was 16.3 months. Upper-segment degeneration was documented in 4 cases (3 new osteophyte, 1 enlargement of osteophyte), whereas lower-segment degeneration was noted in 5 cases (1 new osteophyte, 3 enlargement of osteophyte, 1 decreased disk height). Among the degenerated cases, 4 cases (44.4%) also showed various degrees of HO.


CONCLUSIONS
The rate of adjacent-segment degeneration was higher than that observed in previous studies. Adjacent-segment degeneration documented a tendency toward HO. A longer follow-up period is necessary to investigate and document the different types of degeneration seen at levels adjacent to artificial Bryan cervical disk prostheses.
Yi
Seong
S
Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University, College of Medicine, Seoul 120-752, Korea.
Lee
Dong Yeob
DY
Ahn
Poong Gee
PG
Kim
Keung Nyun
KN
Yoon
Do Heum
DH
Shin
Hyun Chul
HC
D000328:Adult; D001178:Arthroplasty / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D017586:Diskectomy / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D019736:Prostheses and Implants / Q000009:adverse effects; D012189:Retrospective Studies; D055502:Secondary Prevention; D013128:Spinal Osteophytosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D055009:Spondylosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed