Two-year fusion and clinical outcomes in 224 patients treated with a single-level instrumented posterolateral fusion with iliac crest bone graft.
BACKGROUND
Reported fusion rates for spine fusions using iliac crest bone graft (ICBG) vary between 40% and 100% because of different fusion techniques, patient comorbidity, diagnosis and assessment criteria.


OBJECTIVE
We report two-year results of single-level instrumented posterolateral fusions evaluated with radiographs, fine-cut computed tomography (CT) scans with reconstructions and outcome measures. STUDY DESIGN/ SETTING: Retrospective analysis of data from a prospective multicenter randomized clinical controlled trial.


METHODS
Patients with various degenerative diagnoses enrolled in the control arm of a Food and Drug Administration (FDA)-regulated, multicenter trial of single-level decompression and posterolateral fusion for degenerative lumbar disease.


METHODS
Short Form-36 (SF-36), Oswestry Disability Index (ODI), Numeric Rating Scales (0-20) for back, leg, and graft site pain, CT scans, anteroposterior and lateral flexion/extension radiographs.


METHODS
Patients enrolled in an FDA-regulated, multicenter trial at 29 sites with degenerative lumbar disease treated with single-level instrumented posterolateral fusion with ICBG were included in the analysis. Demographic and surgical data were collected. Clinical outcomes were followed using standard metrics. Fusion was assessed by independent radiologists at 6, 12, and 24 months postoperatively. Two fusion criteria were compared: anteroposterior and flexion/extension radiographs to assess motion and bridging bone, with CT scans as needed to confirm bridging bone; and CT scan assessment for bridging bone only.


RESULTS
One hundred ninety-four of 224 subjects (86.6%) completed the study. The mean operative time was 2.9 hours with a blood loss of 448.6 mL. The average graft volume was 36.3 mL. There were 21 (9.4%) wound infections, 18 (8.0%) incidental durotomies, 3 (1.3%) implant displacements, 2 (0.9%) malpositioned implants, and 17 (7.6%) graft-related complications. Twenty-seven patients (13.9%) required reoperation, the majority for nonunions. Fusion rates based on radiographs with selective CTs at 6, 12, and 24 months were 65.3%, 82.5%, and 89.3%, respectively. Fusion rates based on bridging bone on CT scans were 56.1%, 71.5%, 83.9%, respectively. Two-year improvement for all outcome measures was significant (p<.001)-ODI 25.3, SF-36 Physical Component Score (PCS) 12.2, back pain 7.9, and leg pain 7.1. Two years postoperatively, 60% of patients complained of graft site pain (mean pain score=8.5).


CONCLUSIONS
In a large series of patients who had primary single-level instrumented posterolateral fusion with ICBG, evidence of bridging bone on fine-cut CT scans improved with time to 83.9% at 24 months. Significant improvement from baseline was noted in all clinical outcome measures at all time intervals with 75% achieving minimum clinically important difference (MCID) for ODI and 66% achieving MCID for SF-36 PCS.
Dimar
John R
JR
Kenton D. Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202, USA.
Glassman
Steven D
SD
Burkus
J Kenneth
JK
Pryor
Philip W
PW
Hardacker
James W
JW
Carreon
Leah Y
LY
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016025:Bone Transplantation / Q000000981:diagnostic imaging*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007085:Ilium / Q000601:surgery / Q000637:transplantation; D008161:Lumbosacral Region / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011859:Radiography; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D055815:Young Adult