Does restoration of focal lumbar lordosis for single level degenerative spondylolisthesis result in better patient-reported clinical outcomes? A systematic literature review

Functional outcomes correlate with sagittal spinal balance in degenerative lumbar spondylolisthesis surgery

BACKGROUND CONTEXT

Degenerative lumbar spondylolisthesis (DLS) is a debilitating condition associated with poor preoperative functional status. Surgical intervention has been shown to improve functional outcomes in this population though the optimal surgical procedure remains controversial. The importance of maintaining and/or improving sagittal and pelvic spinal balance parameters has received increasing interest in the recent DLS literature. However, little is known about the radiographic parameters most associated with improved functional outcomes among patients undergoing surgery for DLS.

PURPOSE

To identify the effect of postoperative sagittal spinal alignment on functional outcome after DLS surgery.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Two-hundred forty-three patients in the Canadian Spine Outcomes and Research Network (CSORN) prospective DLS study database.

OUTCOME MEASURES

Baseline and 1-year postoperative leg and back pain on the 10-point Numeric Rating Scale and baseline and 1-year postoperative disability on the Oswestry Disability Index (ODI).

METHODS

All enrolled study patients had a DLS diagnosis and underwent decompression in isolation or with posterolateral or interbody fusion. Global and regional radiographic alignment parameters were measured at baseline and 1-year postoperatively including sagittal vertical axis (SVA), pelvic incidence and lumbar lordosis (LL). Both univariate and multiple linear regression was used to assess for the association between radiographic parameters and patient-reported functional outcomes with adjustment for possible confounding baseline patient factors.

RESULTS

Two-hundred forty-three patients were available for analysis. Among participants, the mean age was 66 with 63% (153/243) female with the primary surgical indication of neurogenic claudication in 197/243 (81%) of patients. Worse pelvic incidence-LL mismatch was correlated with more severe disability [ODI, 0.134, p<.05), worse leg pain (0.143, p<.05) and worse back pain (0.189, p<.001) 1-year postoperatively. These associations were maintained after adjusting for age, BMI, gender, and preoperative presence of depression (ODI, R2 0.179, β, 0.25, 95% CI 0.08, 0.42, p=.004; back pain R2 0.152 (β, 0.05, 95% CI 0.022, 0.07, p<.001; leg pain score R2 0.059, β, 0.04, 95% CI 0.008, 0.07, p=.014). Likewise, reduction of LL was associated with worse disability (ODI, R2 0.168, β, 0.04, 95% CI -0.39, -0.02, p=.027) and worse back pain (R2 0.135, β, -0.04, 95% CI -0.06, -0.01, p=.007). Worsened SVA correlated with worse patient reported functional outcomes (ODI, R2 0.236, β, 0.12, 95% CI 0.05, 0.20, p=.001). Similarly, an increase (worsening) in SVA resulted in a worse NRS back pain (R2 0.136, β, 0.01, 95% CI .001, 0.02, p=.029) and worse NRS leg pain (R2 0.065, β, 0.02, 95% CI 0.002, 0.02, p=.018) scores regardless of surgery type.

CONCLUSIONS

Preoperative emphasis on regional and global spinal alignment parameters should be considered in order to optimize functional outcome in lumbar degenerative spondylolisthesis treatment.

Surgical treatment of degenerative lumbar spondylolisthesis: Effect of TLIF and slip reduction on sagittal alignment

INTRODUCTION

The surgical treatment of lumbar degenerative spondylolisthesis (LDS) remains controversial. The aim of this study was to determine the effect of adding transforaminal lumbar interbody fusion (TLIF) to posterolateral fusion (PLF) on the local lordosis, sagittal alignment and potential complications. The second aim was to evaluate the effect of slip reduction on the same parameters.

HYPOTHESIS

The initial hypothesis was that TLIF provides better correction of the local lordosis and that reducing the slip improves the global sagittal balance.

METHODS

In this retrospective, single-center study, patients who had been operated on for LSD at one or two levels by laminectomy and PLF, with or without a TLIF cage, were included. Data collected consisted of age, sex, number of levels fused and whether or not a TLIF cage was used. Fusion was defined as the absence of indirect nonunion signs on radiographs at 2 years postoperative. The occurrence and time frame of any complications and the need for reoperation were documented. Lateral radiographs of the entire spine were analyzed preoperatively, in the early postoperative period (3 to 6 months) and at a minimum follow-up of 2 years. The following parameters were measured: pelvic parameters, C7 sagittal tilt (C7ST), spinosacral angle (SSA), maximum lumbar lordosis (LL), lordosis at slipped level (LS), slip percentage. The analysis compared patients treated by PLF and TLIF and determined the impact of slip reduction.

RESULTS

One hundred and three patients were included in the study (71% women). The mean follow-up was 38 months. The mean age was 69 years. Seventy-seven patients (75%) underwent PLF. Comparing the preoperative and early postoperative data identified 5.4% better spondylolisthesis reduction in the TLIF group than the PLF group (-8.9±9.5% vs -3.5±7.6%; p=0.04) that was not maintained at the final follow-up. The fusion rate was comparable between groups: 94% in APL and 89% in TLIF (p=0.7). The overall complication rate was 46% in the TLIF group versus 33% in the PLF group (p=0.35). A comparison based on whether or not the slip was reduced found significant improvement in the reduction group of the SSA by more than 6° (6.8°±6° vs 0.5°±7.4°; p=0.04). The fusion rate was 91% in the reduced group and 95% in the non-reduced group (p=0.81); the complication rate was 44% versus 28% in the non-reduced group (p=0.10).

CONCLUSION

This study shows that slip reduction helps to improve the sagittal alignment by increasing the SSA when treating LDS. Posterolateral fusion and TLIF produce comparable radiographic outcomes at 2 years postoperative in the segmental lordosis, slip reduction, global sagittal alignment and fusion rate.

LEVEL OF EVIDENCE

IV.

Relationship between lumbar lordosis, pelvic parameters, PI-LL mismatch and outcome after short fusion surgery for lumbar degenerative disease. Literature review, rational and presentation of public study protocol: RELApSE study (registry for evaluation of lumbar artrodesis sagittal alignEment)

Background

Vertebral arthrodesis for degenerative pathology of the lumbar spine still remains burdened by clinical problems with significant negative results. The introduction of the sagittal balance assessment with the evaluation of the meaning of pelvic parameters and spinopelvic (PI-LL) mismatch offered new evaluation criteria for this widespread pathology, but there is a lack of consistent evidence on long-term outcome.

Methods

The authors performed an extensive systematic review of literature, with the aim to identify all potentially relevant studies about the role and usefulness of the restoration or the assessment of Sagittal balance in lumbar degenerative disease. They present the study protocol RELApSE (NCT05448092 ID) and discuss the rationale through a comprehensive literature review.

Results

From the 237 papers on this topic, a total of 176 articles were selected in this review. The analysis of these literature data shows sparse and variable evidence. There are no observations or guidelines about the value of lordosis restoration or PI-LL mismatch. Most of the works in the literature are retrospective, monocentric, based on small populations, and often address the topic evaluation partially.

Conclusions

The RELApSE study is based on the possibility of comparing a heterogeneous population by pathology and different surgical technical options on some homogeneous clinical and anatomic-radiological measures aiming to understanding the value that global lumbar and segmental lordosis, distribution of lordosis, pelvic tilt, and PI-LL mismatch may have on clinical outcome in lumbar degenerative pathology and on the occurrence of adjacent segment disease.

Examining Clinical Opinion and Experience Regarding Utilization of Plain Radiography of the Spine: Evidence from Surveying the Chiropractic Profession

Plain Radiography of the spine (PROTS) is utilized in many forms of healthcare including the chiropractic profession; however, the literature reflects conflicting opinions regarding utilization and value. Despite being an essential part of Evidence-Based Practice (EBP), few studies assess Doctors of Chiropractic (DCs) clinical opinions and experience regarding the utilization of (PROTS) in practice. In this study, DCs were surveyed regarding utilization of PROTS in practice. The survey was administered to an estimated 50,000 licensed DCs by email. A total of 4301 surveys were completed, of which 3641 were United States (US) DCs. The Clinician Opinion and Experience on Chiropractic Radiography (COECR) scale was designed to analyze survey responses. This valid and reliable scale demonstrated good internal consistency using confirmatory factor analysis and the Rasch model. Survey responses show that 73.3% of respondents utilize PROTS in practice and 26.7% refer patients out for PROTS. Survey responses show that, among US DCs, 91.9% indicate PROTS has value beyond identification of pathology, 86.7% indicate that PROTS is important regarding biomechanical analysis of the spine, 82.9% indicate that PROTS is vital to practice, 67.4% indicate that PROTS aids in measuring outcomes, 98.6% indicate the opinion that PROTS presents very low to no risk to patients, and 93.0% indicate that sharing clinical findings from PROTS studies with patients is beneficial to clinical outcomes. The results of the study indicated that based on clinical experience, the majority of DCs find PROTS to be vital to practice and valuable beyond the identification of red flags.

Long-term Radiological and Clinical Outcome after Lumbar Spinal Fusion Surgery in Patients with Degenerative Spondylolisthesis: A Prospective 6-Year Follow-up Study

Objective

To assess which radiological alignment parameters are associated with a satisfactory long‐term clinical outcome after performing lumbar spinal fusion for treating degenerative spondylolisthesis.

Methods

This single‐center prospective study assessed the relation between radiological alignment parameters measured on standing lateral lumbar spine radiographs and the patient‐reported outcome using four different questionnaires (COMI, EQ‐5D, ODI and VAS) as primary outcome measures (level of evidence: II). The following spinopelvic alignment parameters were used: gliding angle, sacral inclination, anterior displacement, sagittal rotation, lumbar lordosis, sacral slope, pelvic tilt and pelvic incidence. Furthermore, the length of stay and perioperative complications were documented. Only cases from 2013 to 2015 of low‐grade degenerative lumbar spondylolisthesis (Meyerding grades I and II) were considered. The patients underwent open posterior lumbar fusion surgery by pedicle screw instrumentation and cage insertion. The operative technique was either a posterior lumbar interbody fusion (PLIF) or a transforaminal lumbar interbody fusion (TLIF) performed by three different senior orthopedic surgeons. Exclusion criteria were spine fractures, minimally invasive techniques, underlying malignant diseases or acute infections, previous or multisegmental spine surgery as well as preoperative neurologic impairment. Of 89 initially contacted patients, 17 patients were included for data analysis (11 males, six females).

Results

The data of 17 patients after mono‐ or bisegmental lumbar fusion surgery to treat low‐grade lumbar spondylolisthesis and with a follow‐up time of least 72 months were analyzed. The mean age was 66.7 ± 11.3 years. In terms of complications two dural tears and one intraoperative bleeding occurred. The average body mass index (BMI) was 27.6 ± 4.4 kg/m² and the average inpatient length of stay was 12.9 ± 3.8 days (range: 8–21). The long‐term clinical outcome correlated significantly with the change of the pelvic tilt (r_s = −0.515, P < 0.05) and the sagittal rotation (r_s = −0.545, P < 0.05). The sacral slope was significantly associated with the sacral inclination (r_s = 0.637, P < 0.01) and the pelvic incidence (r_s = 0.500, P < 0.05). In addition, the pelvic incidence showed a significant correlation with the pelvic tilt (r_s = 0.709, P < 0.01). The change of the different clinical scores over time also correlated significantly between the different questionnaires.

Conclusions

The surgical modification of the pelvic tilt and the sagittal rotation are the two radiological alignment parameters that can most accurately predict the long‐term clinical outcome after lumbar interbody fusion surgery.

Clinical outcome after lumbar spinal fusion surgery in degenerative spondylolisthesis: a 3-year follow-up

INTRODUCTION

Lumbar spinal fusion surgery is a widely accepted surgical treatment in degenerative causes of lumbar spondylolisthesis. The benefit of reduction of anterior displacement and restoration of sagittal parameters is still controversially debated. Purpose of the underlying publication was to analyze the influence of radiographic sagittal parameters of the spine in aspects of changes in postoperative clinical outcome.

MATERIALS AND METHODS

By prospective analysis, we included patients with low-grade degenerative lumbar spondylolisthesis (Meyerding grades I and II) with mono- or bisegmental fusion surgery with a minimum follow-up data of 3 years. For clinical outcome measures, COMI, ODI and EQ-5D were used. Spinopelvic parameters (sacral inclination, pelvic tilt, sacral slope and pelvic incidence, lumbar lordosis and lumbar index as well as anterior displacement and sagittal rotation) were measured on plain radiographs.

RESULTS

We could observe a significant benefit in clinical outcome after lumbar fusion surgery in low-grade spondylolisthesis in our mid-term follow-up data including 32 patients. By surgical reduction, we could see significant restoration of anterior displacement and sagittal rotation. Interestingly, a significant correlation between restoration of both sagittal rotation and sacral inclination and clinical outcome score was observed in the 3-year follow-up.

CONCLUSION

In low-grade spondylolisthesis, spinal fusion surgery is a well-established surgical procedure; however, the impact of sagittal parameters and reduction of anterior displacement remains controversial. Within our findings, restoration of sagittal parameters showed significant correlation to improvement in clinical outcome in our mid-term follow-up data.

Does change in focal lordosis after spinal fusion affect clinical outcomes in degenerative spondylolisthesis?

Study Design:

Retrospective cohort study.

Objective:

The objective of this study is to determine the effect of focal lordosis and global alignment and proportion (GAP) scores on patient reported outcome measures (PROMs) after posterior lumbar fusion for patients with 1- or 2-level lumbar degenerative spondylolisthesis (DS).

Summary of Background Data:

In patients with DS, improvements in spinopelvic parameters are believed to improve clinical outcomes. However, the effect of changing focal lordosis in patients with 1-or 2-level degenerative lumbar spondylolisthesis is unclear.

Materials and Methods:

Postoperative spinopelvic parameters and perioperative focal lordosis changes were measured for 162 patients at a single academic center from January 2013 to December 2017. Patients were divided into three groups: >2° (lordotic group), between 2° and −2° (neutral group), and −2°° (kyphotic group). Patients were then reclassified based on GAP scores. Recovery ratios (RR) and the number of patients achieving the minimal clinically important difference (MCID) were calculated for PROMs. Standard descriptive statistics were reported for patient demographics and outcomes data. Multiple linear regression analysis controlled for confounders. Alpha was set at P < 0.05.

Results:

There was no significant association between change in focal lordosis and surgical complications including adjacent segment disease (P = 0.282), instrumentation failure (P = 0.196), pseudarthrosis (P = 0.623), or revision surgery (P = 0.424). In addition, the only PROM affected by change in focal lordosis was Mental Component Scores (ΔMCS-12) (lordotic = 2.5, neutral = 8.54, and kyphotic = 5.96, P = 0.017) and RR for MCS-12 (lordotic = 0.02, neutral = 0.14, kyphotic 0.10, P = 0.008). Linear regression analysis demonstrated focal lordosis was a predictor of decreased improvement in MCS-12 (β = −6.45 [−11.03- −1.83], P = 0.007). GAP scores suggested patients who were correctly proportioned had worse MCID compared to moderately disproportioned and severely disproportioned patients (P = 0.024).

Conclusions:

The change in focal lordosis not a significant predictor of change in PROMs for disability, pain, or physical function. Proportioned patients based on the GAP score had worse MCID for Oswestry Disability Index.

Level of Evidence:

III

PEEK Versus Titanium Static Interbody Cages: A Comparison of 1-Year Clinical and Radiographic Outcomes for 1-Level TLIFs

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

This study evaluates the patient-reported Health Related Quality of Life outcomes and radiographic parameters of patients who underwent a single level transforaminal lumbar interbody fusion with either a polyetheretherketone (PEEK) or titanium interbody cage.

SUMMARY OF BACKGROUND DATA

Spinal stenosis with instability is a common diagnosis that is often treated with interbody fusion, in particular transforaminal lumbar interbody fusion. Titanium and PEEK interbody cage properties have been extensively studied to understand their effect on fusion rates and subsidence.

MATERIALS AND METHODS

A retrospective cohort study was conducted from a single, high volume, academic hospital. Health Related Quality of Life outcomes were obtained from Outcomes Based Electronic Research Database and electronic medical record chart review. Subsidence was defined as a loss of 2 mm or more in the anterior or posterior disk height. Spinopelvic alignment parameters measured were sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, segmental lordosis, and pelvic incidence-lumbar lordosis mismatch. Fusion rates were assessed by the Brantigan-Steffee criteria.

RESULTS

The study included a total of 137 patients (108 PEEK, 29 titanium). Overall, no significant changes were noted between the 2 groups at 3 month or 1-year follow-up. Perioperatively, patients did report improvement in all outcome parameters within the PEEK and titanium groups. No significant difference was noted in subsidence rate between the 2 groups. Segmental lordosis significantly increased within the PEEK (+4.8 degrees; P<0.001) and titanium (+4.6 degrees; P=0.003) cage groups, however no difference was noted between groups. No significant difference was noted in fusion between the PEEK and titanium cage cohorts (92.6% vs. 86.2%; P=0.36).

CONCLUSION

Overall, while PEEK and titanium cages exhibit unique biomaterial properties, our study shows that there were no significant differences with respect to patient-reported outcomes or radiographic outcomes between the 2 groups at the 1-year follow-up time point.

LEVEL OF EVIDENCE

Level III.

Preliminary Results of Expandable Transforaminal Lumbar Interbody Fusion Cages

Background:

Compared with static cages, expandable cages for Transforaminal Lumbar Interbody Fusion (TLIF), are thought to require less posterior bony removal and nerve root retraction. They may allow the creation of a greater lordotic angle and lordosis restoration.

Objective:

This study investigated whether TLIF using an expandable lordotic interbody cage facilitates an improvement in both segmental lordosis and the restoration of intradiscal height.

Methods:

A total of 32 patients with 40 operated segments underwent TLIF surgery for lumbar degenerative disc disease and were consecutively included in this prospective observational study. Of those patients, 25 received monosegmental treatment, six were treated bisegmentally, and one was treated trisegmentally. All patients were assessed clinically and radiographically preoperatively, as well as one week, six months, and two years postoperatively.

Results:

Two patients required revision for screw loosening and pseudarthrosis. In four patients, the endplate was violated intraoperatively due to cage placement. Postoperatively, cage subsidence was observed in four patients. Significant improvement in the mean degree of spondylolisthesis was noted at the two-year mark. Mean segmental lordosis improved postoperatively. A significant increase in mean disc height of the treated segment was also found. Overall, with the exception of pain, no significant clinical or radiographic changes were reported between the first postoperative week and the two-year year follow-up mark. The mean pain, functional, and quality of life outcomes improved significantly from the preoperative to postoperative period, with no deterioration between six months and two years.

Conclusion:

This study demonstrates that favorable outcomes can be achieved by using an expandable titanium cage in TLIF procedures.

Effect of lumbar laminectomy on spinal sagittal alignment: a systematic review

PURPOSE

Positive spinal sagittal alignment is known to correlate with pain and disability. The association between lumbar spinal stenosis and spinal sagittal alignment is less known, as is the effect of lumbar decompressive surgery on the change in that alignment. The objective was to study the evidence on the effect of lumbar decompressive surgery on sagittal spinopelvic alignment.

METHODS

The Cochrane Controlled Trials Register (CENTRAL), Medline, Embase, Scopus and Web of Science databases were searched in October 2019, unrestricted by date of publication. The study selection was performed by two independent reviewers. The risk of systematic bias was assessed according to the NIH Quality Assessment Tool. The data were extracted using a pre-defined standardized form.

RESULTS

The search resulted in 807 records. Of these, 18 were considered relevant for the qualitative analysis and 15 for the meta-synthesis. The sample size varied from 21 to 89 and the average age was around 70 years. Decompression was mostly performed on one or two levels and the surgical techniques varied widely. The pooled effect sizes were most statistically significant but small. For lumbar lordosis, the effect size was 3.0 (95% CI 2.2 to 3.7) degrees. Respectively, for pelvic tilt and sagittal vertical axis, the effect sizes were - 1.6 (95% CI .2.6 to - 0.5) degrees and - 9.6 (95% CI - 16.0 to - 3.3) mm.

CONCLUSIONS

It appears that decompression may have a small, statistically significant but probably clinically insignificant effect on lumbar lordosis, sagittal vertical axis and pelvic tilt.

Preoperative lordosis in L4/5 predicts segmental lordosis correction achievable by transforaminal lumbar interbody fusion

PURPOSE

The mean potential of lordosis restoration by transforaminal lumbar interbody fusion (TLIF) is supposed to be low in general. In contrast, clinical experience shows a wide range of segmental lordosis correction. In this study, the predictability of lordosis correction should be investigated.

METHODS

Prospectively collected register data were analyzed retrospectively. One hundred twenty-one consecutive patients (2014-2016) operated with single-level TLIF L4/5 (10°-lordotic cage). Segmental lordosis (L4/5) and overall lordosis (L1-S1) were measured on lumbar X-rays: preoperatively (pre), after 3-5 days (post), at least 24 months postoperatively (2yFU). Outcome and satisfaction of patients were assessed. Parameters were statistically compared by students t-tests (a = 0.05). In addition, predictors of correction were analyzed.

RESULTS

Age was 60.7 years, rate of 2yFU 41.3% (n = 50). Lordosis correction L4/5 was statistically significant with (post-pre) 4.9 ± 5.7° (p < 0.01), but not significant for L1-S1 (post-pre) 1.6 ± 8.0° (p = 0.3). A strong-moderate correlation of lordosis L4/5 (pre) and lordosis correction L4/5 (post-pre) was shown (r =  - 0.6, p < 0,01). In a rising range of preoperative lordosis L4/5 from 15-30° the likelihood of lordosis loss increased. In 2yFU correction, L4/5 was significant with (post-pre) 5.4 ± 5.4° (p < 0.01), no significant long-term change (2yFU-postop)  - 1.5 ± 4.9° (p = 0.2). No correlation (r =  - 0.1) of correction and ODI. VAS-B improved by means of 2.9, VAS-L by 2.5, ODI by 19.1% (pre vs. 2yFU), each statistically significant (p < 0.01).

CONCLUSION

Significant segmental relordosation can be performed by TLIF L4/5. The potential of correction strongly correlates with preoperative lordosis. Therefore, TLIF technique should be considered carefully in cases with a preoperative segmental lordosis of more than 15° and additional need of lordosation.

Transfacet Minimally Invasive Transforaminal Lumbar Interbody Fusion With an Expandable Interbody Device-Part II: Consecutive Case Series

BACKGROUND

Advances in operative techniques and instrumentation technology have evolved to maximize patient outcomes following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). The transfacet MIS-TLIF is a modified approach to the standard MIS-TLIF that leverages a bony working corridor to access the disc space for discectomy and interbody device placement.

OBJECTIVE

To evaluate clinical and radiographic results following transfacet MIS-TLIF using an expandable interbody device.

METHODS

We performed a retrospective review of consecutive patients who underwent transfacet MIS-TLIF for degenerative lumbar spondylolisthesis. Patient-reported outcome measures for pain and disability were assessed. Sagittal lumbar segmental parameters and regional lumbopelvic parameters were assessed on upright lateral radiographs obtained preoperatively and during follow-up.

RESULTS

A total of 68 patients (61.8% male) underwent transfacet MIS-TLIF at 74 levels. The mean age was 63.4 yr and the mean follow-up 15.2 mo. Patients experienced significant short- and long-term postoperative improvements on the numeric rating scale for low back pain (-2.3/10) and Oswestry Disability Index (-12.0/50). Transfacet MIS-TLIF was associated with an immediate and sustained reduction of spondylolisthesis, and an increase in index-level disc height (+0.71 cm), foraminal height (+0.28 cm), and segmental lordosis (+6.83°). Patients with preoperative hypolordosis (<40°) experienced significant increases in segmental (+9.10°) and overall lumbar lordosis (+8.65°). Pelvic parameters were not significantly changed, regardless of preoperative alignment. Device subsidence was observed in 6/74 (8.1%) levels, and fusion in 50/53 (94.3%) levels after 12 mo.

CONCLUSION

Transfacet MIS-TLIF was associated with clinical improvements and restoration of radiographic sagittal segmental parameters. Regional alignment correction was observed among patients with hypolordosis at baseline.

Lumbar spinal fusion of low-grade degenerative spondylolisthesis (Meyerding grade I and II): Do reduction and correction of the radiological sagittal parameters correlate with better clinical outcome?

INTRODUCTION

Lumbar and lumbosacral spinal fusion is an established procedure for the treatment of degenerative spondylolisthesis. However, the impact of reduction in the affected segment and of improvement in the radiological sagittal parameters on the clinical outcome remains unclear. Purpose of the study is to analyze the correlation between the radiological sagittal parameters and clinical outcome after lumbar spinal fusion in low-grade degenerative spondylolisthesis.

MATERIALS AND METHODS

In a monocentric prospective, clinical study, patients with low-grade degenerative spondylolisthesis of a single lumbar segment have been included. All patients received a lumbar spinal fusion according to the pathology of the treated segment. Patients attended clinical and radiological follow-up examination 1 and 2 years postoperatively. Clinical outcome was assessed using the Core Outcome Measurement Index (COMI), the Oswestry Disability Index (ODI) and the EuroQol 5D. The sagittal spinopelvic radiological parameters, sagittal rotation and anterior displacement of the affected segment and lumbar lordosis were assessed. The correlation between the sagittal radiological parameters and clinical outcome was analyzed using Spearman-Rho bi-serial test.

RESULTS

Sixty-two patients (35 female and 27 male) with an average age of 59.3 years were included in the study. All patients completed the follow-up examinations. Significant improvement in COMI, ODI and EuroQol 5D scores was shown in all follow-up examinations. Significant reduction in the anterior displacement was measured postoperatively, which was preserved during the follow-up. However, no correlation could be demonstrated between reduction in anterior displacement and improvement in clinical outcome. Nonetheless, correlation between correction of sagittal rotation and clinical outcome was shown.

CONCLUSIONS

Reduction in anterior displacement of the affected segment in the surgical treatment of low-grade degenerative spondylolisthesis does not have an impact on the clinical outcome.

Assessment of radiographic and clinical outcomes of an articulating expandable interbody cage in minimally invasive transforaminal lumbar interbody fusion for spondylolisthesis

OBJECTIVE The inability to significantly improve sagittal parameters has been a limitation of minimally invasive surgery for transforaminal lumbar interbody fusion (MIS TLIF). Traditional cages have a limited capacity to restore lordosis. This study evaluates the use of a crescent-shaped articulating expandable cage (Altera) for MIS TLIF. METHODS This is a retrospective review of 1- and 2-level MIS TLIF. Radiographic outcomes included differences in segmental and lumbar lordosis, disc height, evidence of fusion, and any endplate violations. Clinical outcomes included the numeric rating scale for leg and back pain and the Oswestry Disability Index (ODI) for low-back pain. RESULTS Thirty-nine patients underwent single-level MIS TLIF, and 5 underwent 2-level MIS TLIF. The mean age was 63.1 years, with 64% women. On average, spondylolisthesis was corrected by 4.3 mm (preoperative = 6.69 mm, postoperative = 2.39 mm, p < 0.001), the segmental angle was improved by 4.94° (preoperative = 5.63°, postoperative = 10.58°, p < 0.001), and segmental height increased by 3.1 mm (preoperative = 5.09 mm, postoperative = 8.19 mm, p < 0.001). At 90 days after surgery the authors observed the following: a smaller postoperative sagittal vertical axis was associated with larger changes in back pain at 90 days (r = -0.558, p = 0.013); a larger decrease in spondylolisthesis was associated with greater improvements in ODI and back pain scores (r = -0.425, p = 0.043, and r = -0.43, p = 0.031, respectively); and a larger decrease in pelvic tilt (PT) was associated with greater improvements in back pain (r = -0.548, p = 0.043). For the 1-year PROs, the relationship between the change in PT and changes in ODI and numeric rating scale back pain were significant (r = 0.612, p = 0.009, and r = -0.803, p = 0.001, respectively) with larger decreases in PT associated with larger improvements in ODI and back pain. Overall for this study there was a 96% fusion rate. Fourteen patients were noted to have endplate violation on intraoperative fluoroscopy during placement of the cage. Only 3 of these had progression of their subsidence, with an overall subsidence rate of 6% (3 of 49) visible on postoperative CT. CONCLUSIONS The use of this expandable, articulating, lordotic, or hyperlordotic interbody cage for MIS TLIF provides a significant restoration of segmental height and segmental lordosis, with associated improvements in sagittal balance parameters. Patients treated with this technique had acceptable levels of fusion and significant reductions in pain and disability.

Comparison of Segmental Lordosis and Global Spinopelvic Alignment After Single-Level Lateral Lumbar Interbody Fusion or Transforaminal Lumbar Interbody Fusion

BACKGROUND

Lateral lumbar interbody fusion (LLIF) has steadily increased in popularity. Compared with the traditional transforaminal lumbar interbody fusion (TLIF), LLIF is thought to allow for greater improvement in lordosis. However, there are limited direct comparison data on the degree of regional and global alignment change after single-level LLIF and TLIF procedures. This study compared the changes in spinal sagittal alignment in patients who underwent either procedure.

METHODS

A retrospective analysis of patients who underwent LLIF or TLIF for lumbar degenerative disease at a single institution was performed. Twenty patients who underwent single-level LLIF were matched to 20 patients who underwent single-level TLIF by gender and level of interbody fusion. All included patients had preoperative and postoperative standing scoliosis radiographs. Changes in segmental lordosis (SL) at the fused level, lumbar lordosis (LL), sagittal vertical axis, and pelvic incidence-LL mismatch (PI-LL) were measured. Statistical analysis was performed using paired and unpaired Student's t-tests. Means were reported with standard error.

RESULTS

Within each group, 2, 4, and 14 patients had cages placed at L2-3, L3-4, and L4-5, respectively. The LLIF group demonstrated significantly increased SL compared with the TLIF group (+4.9° ± 3.0 vs. +2.6° ± 1.7, P = 0.01). LL, sagittal vertical axis, and PI-LL changes did not differ significantly between groups.

CONCLUSIONS

LLIF achieved greater improvements in SL than TLIF. However, regionally and globally, there were no significant differences with either procedure after a single-level intervention. The increased lordosis from LLIF compared with TLIF may be more impactful globally in multilevel fusions.

Short Lumbosacral Decompression Plus Fixation Does Not Change the Spinopelvic Balance on Patients With Moderate Degenerative Spondylolisthesis and Associated Spinal Stenosis

STUDY DESIGN

A retrospective cohort study.

OBJECTIVES

To investigate whether decompression plus short segment lumbosacral fixation changes the sagittal baseline spinopelvic parameters in patients with moderate degenerative spondylolisthesis (DS) and associated degenerative lumbar spinal stenosis (DLSS).

SUMMARY OF BACKGROUND DATA

Spinal decompression and fusion are commonly performed in DS with associated DLSS. Spinopelvic alignment after surgery for DS is an important research topic. The effect of short lumbosacral instrumented fusion on the global sagittal spinal balance has not been sufficiently studied.

METHODS

Thirty-four consecutive adult patients (21 women, 13 men) aged 62 ± 11 years with balanced spines [sagittal vertical axis (SVA) ≤ 40 mm] received decompression and two to three vertebrae fixation plus fusion for DS grades I and II, associated with symptomatic DLSS. Age, gender, number of segments fused, posterolateral fusion (PLF) versus PLF plus posterior lumbar interbody fusion (PLIF) and segmental lordosis (SL) in the free segment above instrumentation were studied for a minimum follow-up of 60 months. The roentgenographic variables measured are T12-S1 lumbar lordosis (LL), SVA, sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), SL, and anterior (ADH) and posterior disc height (PDH) in the suprajacent free lumbar segment. Clinical outcomes were assessed with visual analog scale and Oswestry Disability Index.

RESULTS

SVA significantly (p = .05) decreased postoperatively but returned to the baseline value at the final observation. Younger individuals (≤59 years) stood with greater SS (p = .036) 6 months postoperatively and with less SVA in all 3 periods of observation (p = .013, .046, and .024) than their older (>59 years) counterparts. Patients with monosegmental stenosis showed on baseline less SVA (p = .028), PT (p = .031), and PI (p = .004) than their two-segmental stenosis counterparts. PI preoperatively to the last evaluation was significantly smaller in the patients who received 360° fusion (p<.016).

CONCLUSIONS

Short lumbosacral fixation does not significantly change the preoperative sagittal spinopelvic balance in adult patients with preoperatively balanced spines who have DS and DLSS.

LEVEL OF EVIDENCE

Level III.