Posterior Interspinous Fusion Device for One-Level Fusion in Degenerative Lumbar Spine Disease : Comparison with Pedicle Screw Fixation - Preliminary Report of at Least One Year Follow Up

OBJECTIVE: Transpedicular screw fixation has some disadvantages such as postoperative back pain through wide muscle dissection, long operative time, and cephalad adjacent segmental degeneration (ASD). The purposes of this study are investigation and comparison of radiological and clinical results between interspinous fusion device (IFD) and pedicle screw. METHODS: From Jan. 2008 to Aug. 2009, 40 patients underwent spinal fusion with IFD combined with posterior lumbar interbody fusion (PLIF). In same study period, 36 patients underwent spinal fusion with pedicle screw fixation as control group. Dynamic lateral radiographs, visual analogue scale (VAS), and Korean version of the Oswestry disability index (K-ODI) scores were evaluated in both groups. RESULTS: The lumbar spine diseases in the IFD group were as followings; spinal stenosis in 26, degenerative spondylolisthesis in 12, and intervertebral disc herniation in 2. The mean follow up period was 14.24 months (range; 12 to 22 months) in the IFD group and 18.3 months (range; 12 to 28 months) in pedicle screw group. The mean VAS scores was preoperatively 7.16+/-2.1 and 8.03+/-2.3 in the IFD and pedicle screw groups, respectively, and improved postoperatively to 1.3+/-2.9 and 1.2+/-3.2 in 1-year follow ups (p<0.05). The K-ODI was decreased significantly in an equal amount in both groups one year postoperatively (p<0.05). The statistics revealed a higher incidence of ASD in pedicle screw group than the IFD group (p=0.029). CONCLUSION: Posterior IFD has several advantages over the pedicle screw fixation in terms of skin incision, muscle dissection and short operative time and less intraoperative estimated blood loss. The IFD with PLIF may be a favorable technique to replace the pedicle screw fixation in selective case.

The Revision Operation Rate for Adjacent Segmental Degeneration by Survival Analysis in Mono-segment Lumbar Fusion / 대한정형외과학회잡지

PURPOSE: To analyze survival rates of patients after mono-segmental lumbar or lumbosacral fusion and to evaluate factors affecting the revision operation due to adjacent segmental degeneration. MATERIALS AND METHODS: This study enrolled 1,206 patients who had mono-segmental lumbar or lumbosacral fusion between March 1997 and December 2006 at the Seoul Spine Institute. The survival rates for the revision operation due to adjacent segmental degeneration were analyzed retrospectively. The age at index operation, sex, etiologic diagnosis, fusion method, fusion level, substance of bone graft, operator, body mass index (BMI), and smoking were considered as risk factors for the revision operation. RESULTS: There were 27 patients with a revision operation for adjacent segmental degeneration (2.24%). The average follow-up period was 39.0 months (6 months to 12 years 6 months) and the average age at operation was 47.0 years (13 to 85 years). The survival rate at 5 years was 97.3%, and at 10 years it was 89.4%. Patients less than 50 years old had a significantly lower revision operation rate than those aged 50 or more (p=0.002). When fusion between the 4th lumbar and the 5th lumbar spinal vertebrae was done, the revision operation rate was significantly higher than for other levels (p=0.003). Obese patients with BMI> or =25 had a significantly higher revision rate than did patients with BMI0.05). In multivariate analysis, age alone was a significant risk factor (p=0.048, Hazard ratio=2.50). CONCLUSION: The most important factor for survival without revision surgery for adjacent segmental degeneration following instrumented mono-segment lumbar or lumbosacral fusion is the age at index operation. Patients 50 year-old or older should be informed of the possibility of adjacent segmental disease after instrumented mono-segment lumbar or lumbosacral fusion.

Correlation Between Clinical Result and Adjacent Segment Degeneration After Lumbar Spinal Fusion / 대한척추외과학회지

STUDY DESIGN: Retrospective study OBJECTIVES: To determine the relationship between clinical outcome and adjacent segment degeneration (ASD) after lumbar fusion. SUMMARY OF LITERATURE REVIEW: Few studies have analyzed the correlation between clinical outcomes and ASD. MATERIALS AND METHODS: Between January 2000 and December 2004, 217 patients who underwent lumbar spinal fusion (>2 years of follow-up) were evaluated. The patients were divided into 2 groups: one-segment (A) and two-segment (B). The UCLA grading scale was used to evaluate the prevalence of ASD on radiography. The association between clinical outcome and ASD was evaluated by Spearman's correlation. RESULTS: ASD occurred in 11.6% (13/112) of patients in group A and 15.2% (16/105) of patients in group B. The number of cases which progressed to more than 2 levels of the degenerative grade were 0 cases in group A and 13 cases (81.3%) in group B. In A, 5 out of 13 ASD cases downgraded one level in their clinical outcomes. In B, all 16 ASD cases downgraded more than one level in their clinical outcomes. Worsening in degenerative grade, was correlated with worse clinical outcome (Spearman's rho = 0.829, P <0.05). CONCLUSIONS: The association of clinical outcomes with ASD after fusion showed a significant correlation, especially association with ASD after multiple segment fusion.