Limited Unilateral Decompression and Pedicle Screw Fixation with Fusion for Lumbar Spinal Stenosis with Unilateral Radiculopathy: A Retrospective Analysis of 25 Cases

Abstract

Objective: Lumbar spinal stenosis is conventionally treated with surgical decompression. However, bilateral decompression and laminectomy is more invasive and may not be necessary for lumbar stenosis patients with unilateral radiculopathy. We aimed to report the outcomes of unilateral laminectomy and bilateral pedicle screw fixation with fusion for patients with lumbar spinal stenosis and unilateral radiculopathy.

Methods: Patients with lumbar spinal stenosis with unilateral lower extremity radiculopathy who received limited unilateral decompression and bilateral pedicle screw fixation were included and evaluated using visual analog scale (VAS) pain and the Oswestry Disability Index (ODI) scores preoperatively and at follow-up visits. Ligamentum flavum thickness of the involved segments was measured on axial magnetic resonance images.

Results: Twenty-five patients were included. The mean preoperative VAS score was 6.6±1.6 and 4.6±3.1 for leg and back pain, respectively. Ligamentum flavum thickness was comparable between the symptomatic and asymptomatic side (p=0.554). The mean follow-up duration was 29.2 months. The pain in the symptomatic side lower extremity (VAS score, 1.32±1.2) and the back (VAS score, 1.75±1.73) significantly improved (p=0.000 vs. baseline for both). The ODI improved significantly postoperatively (6.60±6.5; p=0.000 vs. baseline). Significant improvement in VAS pain and ODI scores were observed in patients receiving single or multi-segment decompression fusion with fixation (p<0.01).

Conclusion: Limited laminectomy and unilateral spinal decompression followed by bilateral pedicle screw fixation with fusion achieves satisfactory outcomes in patients with spinal stenosis and unilateral radiculopathy. This procedure is less damaging to structures that are important for maintaining posterior stability of the spine.

Keywords: Lumbar spinal stenosis; Pedicle screw instrumentation; Unilateral decompression; Unilateral radiculopathy.

Fig. 1. Schematic drawing of ligamentum flavum thickness measurement. Solid arrow indicates the ligamentum flavum and double white arrow indicates the thickest portion of the ligamentum flavum where measurement was made.

Fig. 2. A 42-year-old female with spinal stenosis accompanied by unilateral radiculopathy of the left lower extremity for 1 year. A : Preoperative MRI revealed thickening of the ligamentum flavum (by white arrow). The symptomatic (L)/asymptomatic (R) ratio of bilateral ligamentum thickness at L4/5=1.24. B : Bilateral L4/5 pedicle screw fixation, left decompression TLIF were performed. C : Postoperative MRI. The white triangle points to L4/L5 with left hemilaminectomy and excision of the ligamentum flavum. White arrow shows the intact right side. D : Postoperative CT showed left hemilaminectomy (arrow).

Fig. 3. A 61-year-old female with intermittent back pain for more than 10 years, accompanied by posterolateral radiating pain of the left lower leg with intermittent claudication for more than 2 years. A : Preoperative MRI revealed bilateral L3-4 ligamentum flavum thickening. White arrow indicates thickness on the left side was greater than the right side. B : Preoperative MRI revealed bilateral L4-5 ligamentum flavum thickening. White arrow indicates thickness on the right side was greater than on the left side. C : Bilateral pedicle screw fixation was performed at L3 to L5, and the right laminae and facet joints at L3 to L5 received morselized bone graft. L3-5 left lamina and ligamentum flavum were partially excised, and transforaminal lumbar interbody fusion was performed. D : Postoperative MRI. The white triangle points to L4/5 with left hemilaminectomy and excision of the ligamentum flavum. White arrow shows the normal right side. E : Postoperative MRI. The white triangle points to L3/4 with left hemilaminectomy and excision of the ligamentum flavum. F : Postoperative MRI of L4/5 intervertebral space. The pointed white triangle indicates the left (symptomatic) vertebral plate and the excised ligamentum flavum. Dural sac decompression and bulging are satisfactory. White arrow indicates the right (asymptomatic) vertebral plate and ligamentum flavum. G : Postoperative CT scan of L4/5 intervertebral space. The pointed white triangle indicates left (symptomatic) vertebral plate and the excised ligamentum flavum. Dural sac decompression and bulging are satisfactory.