Posterior lumbar interbody fusion for grade II spondylolisthesis

Radiographic Analysis of Pedicle Screw Retractor-Assisted Transforaminal Lumbar Interbody Fusion for Single-Segment Spondylolisthesis in Adults: A Retrospective Study and Technical Note

Objectives

The objective of this study was to introduce a retractor that can be temporarily installed on unilateral pedicle screws to achieve distraction‐reduction and nerve root protection, and to analyze the efficacy and safety of retractor‐assisted transforaminal lumbar interbody fusion (TLIF) in the treatment of lumbar spondylolisthesis.

Methods

This was a retrospective study of 125 patients who underwent retractor‐assisted TLIF for single‐segment spondylolisthesis from November 2017 to February 2021. Based on morphology, patients were divided into degenerative (N = 66) and isthmic groups (N = 59). Differences in demographics and preoperative characteristics between the groups were analyzed using the independent samples t‐test and χ² test. Changes in radiographic parameters (disc height, foramen height, spondylolisthesis degree, slippage length, and segmental lordosis) before and after surgery were compared using the paired samples t‐test. Logistic regression analysis was performed to analyze the relationship between facet joint angle (FJA) and degenerative lumbar spondylolisthesis (DLS).

Results

Unilateral screw retractor‐assisted TLIF significantly corrected spondylolisthesis and improved disc height and segmental lordosis (p < 0.05). There was no significant difference in foramen height between the two sides before and after operation (pre: 15.81 ± 3.58 mm vs 15.69 ± 3.68 mm, p = 0.599; post: 18.65 ± 2.31 mm vs 18.74 ± 2.26 mm, p = 0.516). The degree of spondylolisthesis in the DLS group before surgery was significantly lower than that in the isthmic spondylolisthesis group (17.70 ± 5.62% vs 25.18 ± 9.73%, p < 0.001), whereas a similar degree of correction could be achieved after surgery (5.91 ± 3.12% vs 7.16 ± 5.69%, p = 0.135). FJAs from L3/4 to L5/S1 were significantly smaller in patients with DLS than those in with isthmic spondylolisthesis (p < 0.05). Patients with facet sagittalization were more likely to have DLS (β: −0.101, odds ratio [OR]:0.904, 95% confidence interval [CI]: 0.874–0.934, p < 0.001), while the cut‐off FJA of L4/5 for predicting L4 spondylolisthesis was 53.19.

Conclusions

Pedicle screw retractor‐assisted TLIF is effective and safe in treating both degenerative and isthmic lumbar spondylolisthesis. The unilateral retractor has the capacity to maintain the disc height achieved by paddle distractors, which optimizes the nerve protection and distractor placement. Patients with an FJA on L4/5 <53.19 were more likely to have DLS.

Factors associated with using an interbody fusion device for low-grade lumbar degenerative versus isthmic spondylolisthesis: a retrospective cohort study

OBJECTIVE

Many studies have utilized a combined cohort of patients with degenerative spondylolisthesis (DS) and isthmic spondylolisthesis (IS) to evaluate indications and outcomes. Intuitively, these are very different populations, and rates, indications, and outcomes may differ. The goal of this study was to compare specific patient characteristics associated with the utilization of a posterior lumbar interbody device between cohorts of patients with DS and IS, as well as to compare rates of interbody device use and patient-rated outcomes at 1 year after surgical treatment.

METHODS

The authors included patients who underwent posterior lumbar interbody fusion or instrumented posterolateral fusion for grade I or II DS or IS and had been enrolled in the Canadian Spine Outcomes and Research Network registry from 2009 to 2016. The outcome measures were score on the Oswestry Disability Index, scores for back pain and leg pain on the numeric rating scale, and mental component summary (MCS) score and physical component summary score on the 12-Item Short-Form Health Survey. Descriptive statistics were used to compare spondylolisthesis groups, logistic regression was used to compare interbody device use, and the chi-square test was used to compare the proportions of patients who achieved a minimal clinically important difference (MCID) at 1 year after surgery.

RESULTS

In total, 119 patients had IS and 339 had DS. Patients with DS were more commonly women, older, less likely to smoke, and more likely to have neurogenic claudication and comorbidities, whereas patients with IS more commonly had radicular pain, neurological deficits, and worse back pain. Spondylolisthesis was more common at the L4-5 level in patients with DS and at the L5-S1 level in patients with IS. Similar proportions of patients had an interbody device (78.6% of patients with DS vs 82.4% of patients with IS, p = 0.429). Among patients with IS, factors associated with interbody device utilization were BMI ≥ 30 kg/m2 and increased baseline leg pain intensity. Factors associated with interbody device utilization in patients with DS were younger age, increased number of total comorbidities, and lower baseline MCS score. For each outcome measure, similar proportions of patients in the surgical treatment and spondylolisthesis groups achieved the MCID at 1 year after surgery.

CONCLUSIONS

Although the demographic and patient characteristics associated with interbody device utilization differed between cohorts, similar proportions of patients attained clinically meaningful improvement at 1 year after surgery.