4:48 Degenerative lumbar spondylolisthesis: a retrospective outcomes study comparing noninstrumented and instrumented fusion with preoperative disc height

Abstract

Purpose of study: The surgical management of lumbar degenerative spondylolisthesis (DLS) often includes decompression and fusion. The addition of transpedicular instrumentation to improve upon fusion rate and outcome remains controversial. Some advocate the use of instrumentation when excessive segmental motion or translation is present. In the absence of radiographic motion, or “stable” spondylolisthesis, the use of fixation becomes less clear. The purpose of this study is to assess the impact of preoperative disc height on the outcome of surgery for DLS with and without instrumentation.Methods used: The outcomes of 65 patients with DLS treated with surgery were retrospectively reviewed. Thirty patients (24 women, 6 men; 59.3±10.4 years of age) underwent transpedicular instrumented posterolateral fusion (INST). Thirty-five patients (22 women, 13 men; 68.6±7.0 years of age) underwent in situ posterolateral fusion (ISF). Average follow-up was 36.7 months. Clinical evaluation at long-term follow-up included chart reviews and telephone questionnaires including back and leg pain visual analog scale (VAS), functional assessment and overall patient satisfaction. Radiographic analysis included preoperative measurements of central disc height. Analysis included all patients treated with or without fixation and subgrouped by preoperative disc height less than or equal to 8 mm or greater than 8 mm (Table 1)Table 1Degenerative spondylolisthesis outcomesDisc height (mm)Back pain*Leg painSittingLiftingWalkingActivitySatisfactionRepeat surgical decisionIn situ fusion (all)8.32 ± 3.81.89 ± 1.22.5 ± 1.41.93 ± 1.22.89 ± 1.673.17 ± 1.12.03 ± 0.731.38 ± 0.861.38 ± 1.08>9 mm11.05 ± 2.52.07 ± 1.492.67 ± 1.441.87 ± 1.362.87 ± 1.883.27 ± 1.092.13 ± 0.631.4 ± 0.911.53 ± 1.41<8 mm5.20 ± 2.11.88 ± 1.32.5 ± 1.451.87 ± 1.083.19 ± 1.63.19 ± 1.22.0 ± 0.631.50 ± 1.031.43 ± 1.09Instrumented fusion (all)7.62 ± 3.541.72 ± 1.072.39 ± 1.52.65 ± 1.563.78 ± 1.563.04 ± 1.232.08 ± 0.831.50 ± 0.831.65 ± 1.33>9 mm10.58 ± 1.671.78 ± 0.972.56 ± 1.741.89 ± 1.363.78 ± 1.093.0 ± 1.242.0 ± 0.821.5 ± 0.972.1 ± 1.79<8 mm5.26 ± 2.61.69 ± 1.22.28 ± 1.43.14 ± 1.53.78 ± 1.82.93 ± 1.32.06 ± 0.881.47 ± 0.741.28 ± 0.72*Back pain scale: 1 = improved, 5 = worse.. No patient had evidence of dynamic translation or significant angulation on initial radiographs. DLS was treated at L4–L5 in 83%, L3–L4 in 12% and L5–S1 in 4%.of findings: The findings are summarized in Table 1. VAS and functional assessments are based on a 1 to 5 scale (1 = improved, 5 = worsened).Relationship between findings and existing knowledge: The literature is replete with various studies assessing the role of instrumentation in lumbar degenerative conditions. The current study is in agreement with numerous studies suggesting that instrumentation may not be especially beneficial in terms of functional outcome in “stable” degenerative spondylolisthesis.Overall significance of findings: The results suggest no significant advantage in the use of instrumentation in DLS in the absence of significant radiographic motion regardless of preoperative disc height, although there was a trend toward less back pain with fixation.Disclosures: Device of drug: pedicle screw instrumentation. Status: approved.Conflict of interest: Louis Jenis, grant research support.