332 - Single Level Posterior Lumbar Fusion and Decompression for Degenerativ...

#332 Single Level Posterior Lumbar Fusion and Decompression for Degenerative Spondylolisthesis-comparison between Pedicle Screws and Spinous Process Fixation - Up to Two Year Follow-up

Oral Posters: Lumbar

Presented by: R. Tatsumi

Author(s):

R. Tatsumi (1)

(1) Northwest Spine Foundation, Tualatin, OR, USA

Abstract

Aims: Lumbar decompression with an instrumented posterior fusion is an accepted surgical procedure for patients with symptomatic degenerative spondylolisthesis with stenosis. Numerous studies have evaluated the use of pedicle screw (PS) fixation for this diagnosis. However, no long term studies have evaluated the clinical, radiological, and cost differences between spinous process (SP) and PS hardware fixation for this condition.

Methods: 75 consecutive patients underwent a posterior fusion with PS (15) or SP (60) fixation at a single center by a single surgeon. Independent review of demographic, intraoperative and post-operative data was performed. Oswestry disability index (ODI) and SF-36 values were prospectively collected pre-operatively and up to 2 years post-operatively. Flexion/Extension/AP radiographs were obtained at 1 and 2 years to evaluate for a posterior lumbar fusion and were independently read by a blinded radiologist. Clinical measures were prospectively collected and evaluated to assess surgical details and complications.

Results: The SP group significantly differed (p< 0.01) from the pedicle screw group for mean age of (SP 73.36; PS 62.74), operating room time (SP 113.28 min; PS 232.67 min) and length of hospital stay (SP 27.89 hrs; PS 71.53 hrs). The changes in the ODI scores were statistically significant for improvement in the SP group compared with the PS group at 6 weeks and three months post-operatively. There was no statistically significant difference between the two groups for SF-36. Radiographs demonstrated no motion at the affected segment with 73% bridging bone in the PS group and 82% in the PS group. There was 1 intraoperative dural tear in the PS group and 2 intraoperative dural tears in the SP group, all were repaired intraoperatively. Re-operations in the PS group were due to pedicle screw removal (2) and adjacent level stenosis (1). No re-operations in the SP occurred and there were no spinous process fractures. In terms of costs, the spinous process group had lower hardware/biologic costs, (SP $11449; PS $13546), lower hospital costs (SP $30,415; PS $45458), with no significant difference in insurance payment (SP $23,015; PS $25,059). The hospital collected a higher percentage of their charges with the SP group versus the PS group (SP 75.6%; PS 55.1%). In terms of costs, the SP group had lower hardware/biologic costs, (SP $11449; PS $13546), lower hospital costs (SP $30,415; PS $45458), with no significant difference in insurance payment (SP $23,015; PS $25,059). The hospital collected a higher percentage of their charges with the SP group versus the PS group (SP 75.6%; PS 55.1%).

Conclusions: The use of spinous process fixation compared with pedicle screws for posterior lumbar fusion for spondylolisthesis and stenosis reduces operative time and shortens the hospital stay. The SP group demonstrated earlier improvement in ODI scores at 6 weeks and 3 months. There was no motion in either group however there was a higher rate of bridging bone in the SP group. SP fixation had a lower revision rate with no need for hadware removal and less adjacent level stenosis. In regards to cost, the SP group had a lower hardware/biologic, lower hospital charges with a higher collection percentage for the hospital.