85SProceedings of the NASS 23rd Annual Meeting / The Spine Journal 8 (2008) 1S–191S

STUDY DESIGN/ SETTING: The study is based on data from a single

investigative site of a United States Food and Drug Administration con-

trolled, randomized, prospective device study of the Bryan artificial cervi-

cal disc. Patients were assessed immediately following implantation and at

12 and 24 weeks and at 12, 24, 48 and 60 months with clinical evaluation

and radiographs. Osteolysis was suspected if loss of bone adjacent to the

device was identified on any follow up film compared to the initial postop-

erative lateral cervical spine view.

PATIENT SAMPLE: There were 32 patients who underwent Bryan cer-

vical artificial disc implantation. Of these patients, 28 were randomized to

device treatment during the clinical study. Continued access following

study closure added three patients and compassionate use was granted

for one patient not meeting study criteria.

OUTCOME MEASURES: Outcome assessment tools included the Neck

disability Index (NDI), Patient Global assessment (Odom’s criteria), Short

Form 36 (SF-36) and Neurological Examination Report Form.

METHODS: Radiographs including AP, lateral and flexion extension

views were reviewed for each patient. It was determined that the lateral ra-

diograph was most informative. Each patient’s lateral films were reviewed

in chronologic order. In addition to demographic data, the earliest onset of

osteolysis, progression of bone loss and clinical symptoms were recorded.

RESULTS: Of the 32 Bryan artificial cervical disc patients, three showed

bone loss rated as moderate in two and severe in one. The initial xray ev-

idence of bone loss was noted as early as six and as late as 48 months in

these patients. One patient was asymptomatic while the other two noted

neck pain. There was no difference in age, symptom presentation, cigarette

smoking or surgical treatment in these three patients compared to the other

29 patients without osteolysis. All three patients were female.

CONCLUSIONS: The etiology of bone loss with cervical arthroplasty in

this study remains unknown. No patient has yet consented to device ex-

plantation, thus the question; "is the loss of bone due to osteolysis?" can’t

be answered. However, the time course and progression in two of our cases

makes osteolysis a strong consideration. Device dislodgement is a concern

in view of the progressive bone loss in those cases. Hence, our recommen-

dation for device explantation. Our experience, though limited, suggests

that annual cervical radiographs after cervical disc arthroplasty should

be performed during the first 3 to 5 years following implantation.

FDA DEVICE/DRUG STATUS: Bryan artificial cervical disc: Investiga-

tional/Not approved.

doi:10.1016/j.spinee.2008.06.201

167. Odontoid Fractures in the Elderly: A Retrospective View of

Complications and Outcomes

Eddie Powell, MD1, Dina Jones, PT, PhD1, Sanford Emery, MD, MBA2,

John France, MD1; 1West Virginia University, Morgantown, WV, USA;2Morgantown, WV, USA

BACKGROUND CONTEXT: Odontoid fractures are particularly diffi-

cult to treat in the elderly. While recommendations range from collar im-

mobilization to surgical fusion, few studies have examined outcomes in the

elderly population.

PURPOSE: The purpose of this study was to determine the overall mor-

tality and morbidity associated with different treatment strategies for odon-

toid fractures in the elderly.

STUDY DESIGN/ SETTING: Retrospective medical record review.

PATIENT SAMPLE: 59 patients, aged 65 years or older, who were diag-

nosed with Type II or III odontoid fractures between 1994 and 2004.

OUTCOME MEASURES: The primary outcome measure was the prev-

alence of surgical and medical complications, including death.

METHODS: Medical records were reviewed for mechanism of injury,

type of odontoid fracture (II versus III), direction of displacement, the

presence of associated cervical or other injuries, treatment (collar, halo, an-

terior screw, or posterior fusion), complications, length of inpatient stay,

and duration of follow-up. Comorbid conditions were assessed using the

Charlson Index. Exclusion criteria included pathological fractures and

deaths prior to the initiation of treatment. Continuous data were analyzed

using the Independent t-Test or Mann-Whitney test, as appropriate.

Nominal and ordinal data were analyzed with Chi-Square or Fisher Exact

tests.

RESULTS: Fifty-six patients (24 males, 32 females) with a mean age of

80.767.3 years (range 65 to 94) met the inclusion criteria. Over three-

quarters (78.6%) of the injuries were due to a fall. Type II fractures were

more prevalent than Type III fractures [37 (66.1%) versus 19 (33.9%)].

Halo [26 (46.4%)] and collar [17 (30.4%)] immobilization were more com-

monly used treatments than anterior screws [7 (12.5%)] or posterior fusion

[6 (10.7%)]. Those patients with initial surgical procedures had higher,

though non-significant, rates of death (23.1%) as compared with those with

non-surgical procedures (6.9%). Complications from any treatment were

present in one-half of the population [29 (51.8%)], with the highest prev-

alence of orthopaedic complications in those patients with anterior screw

or halo as the initial procedure [6 (85.7%) and 14 (53.8%)]. Patients with

Type II fractures were more likely to have complications than those with

Type III (p50.03), and more severe comorbidities were marginally related

to the occurrence of complications (p50.05).

CONCLUSIONS: Elderly patients present with many medical comorbid-

ities and complications can be expected regardless of treatment choice.

Mortality rates were higher in the surgical patients without reaching statis-

tical significance. Of interest is that collar treatment for these fractures did

not result in increased morbidity or mortality in this lower demand patient

population.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

doi:10.1016/j.spinee.2008.06.202

168. Cervical Sagittal Plane Decompensation After Pediatric AIS

Surgery

Darryl Antonacci, MD, FACS1, Patrick Cahill, MD1, Jason Nydick2,

Jahangir Asghar, MD1, Mark Tantorski2, David Clements3, Randal Betz,

MD1, Amer Samdani1; 1Shriners Hospital for Children, Philadelphia, PA,

USA; 2Philadelphia College of Osteopathic Medicine, Philadelphia, PA,

USA; 3Cooper Bone & Joint Institute, Camden, NJ, USA

BACKGROUND CONTEXT: There have been several attempts to char-

acterize the relationship between thoracic kyphosis, lumbar lordosis, and

pelvic alignment in sagittal balance but none to correlate the effect of post-

operative thoracic kyphosis on the cervical spine.

PURPOSE: To correlate the effect of postoprative thoracic kyphosis on

the cervical spine.

STUDY DESIGN/ SETTING: Retrospective analysis.

PATIENT SAMPLE: 22 patients met the inclusion criteria.

OUTCOME MEASURES: Analysis of pre- and post-op radiographs.

METHODS: Radiographic parameters were evaluated on patients under-

going pedicle screw posterior spinal instrumentation and fusion (PSIF) for

Lenke Type 1 and 2 curves with two year follow-up and adequate C-spine

visualization. Parameters included: fusion levels, cervical sagittal balance

(C2-C7), thoracic sagittal balance (T2-T12, T5-T12), lumbar sagittal bal-

ance, C2 & C7 plumb lines, Risser, Cobb angles, sacral slope, pelvic inci-

dence, tilt, and obliquity.

RESULTS: Pre-op, 6 of 22 (Group A) had frank cervical kyphosis (mean

þ10.5 �) and mean pre-op T2-T12 kyphosis of 26.2 �. Post-op, Group A re-

mained in cervical kyphosis with mean thoracic kyphosis:19.5 (p!.05).

Pre-op, 16 of 22 had neutral to lordotic cervical spines (mean �13.75 �)with thoracic kyphosis (mean: 45 �). Post-op, 8/16 (Group B) developed

cervical sagittal decompensation (O5 �) with 6 developing frank cervical

kyphosis (mean þ10.5 �, p!.006). In Group B, post-op thoracic kyphosis

was 25.6 �, p!.004. The other 8 of 16 (Group C) did not decompensate

cervically and had a post-op thoracic kyphosis of 37.5 � (vs. Group B.,

p!.05). Of the remaining parameters, only sacral slope demonstrated