Postoperative bone re-growth in lumbar spinal stenosis. A multivariate analysis of 48 patients.
METHODS
Forty-eight patients who underwent posterior decompressive surgery for lumbar spinal stenosis were studied. The effect of bone re-growth after posterior decompression in lumbar spinal stenosis on clinical outcome and the factors promoting the bone re-growth were investigated with a multivariate analysis model.


METHODS
Bone re-growth at the sites operated upon was evaluated as a percentage of re-growth of the original laminectomy site based upon plain radiographs. The degree of bone re-growth was classified into four groups: 1) no significant re-growth (Group I, bone regrowth rate 10% or less); mild (Group II, 11% to 40%), moderate (Group III, 41% to 70%), and marked (Group IV, 71% to 100%). The average follow-up period was 4.5 years (range, 2 to 7 years).


RESULTS
No significant bone re-growth was shown in 6% of the patients. Mild re-growth was shown in 50%, moderate re-growth in 29%, and marked re-growth in 15%. A multivariate analysis indicated that a total block in the preoperative myelogram, a follow-up period of more than 5 years, decompression at more than three spinal levels, and age under 60 years were associated with moderate or marked bone re-growth. Spinal instability accelerated the bone re-growth mainly in the mid and later follow-up intervals. Spinal levels adjacent to a fusion showed more bone re-growth. Patients with moderate and marked bone re-growth had poorer clinical outcomes than those with no significant and mild bone re-growth.


CONCLUSIONS
Bone re-growth in a surgical defect will occur in most patients after posterior decompression. Moderate and marked postoperative bone re-growth are possibly related to recurrence of neurologic symptoms in the middle of and later on in follow-up periods.
Chen
Q
Q
Department of Orthopaedic Surgery, Fukui Medical School, Japan.
Baba
H
H
Kamitani
K
K
Furusawa
N
N
Imura
S
S
D000368:Aged; D001861:Bone Regeneration; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007796:Laminectomy; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D008297:Male; D015233:Models, Statistical; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000453:epidemiology; D011859:Radiography; D013123:Spinal Fusion; D013130:Spinal Stenosis / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D017211:Treatment Failure