Characteristics of Spinopelvic Sagittal Alignment in Lumbar Degenerative Disease

Sagittal Alignment in the Degenerative Lumbar Spine: Surgical Planning

➤ Sagittal alignment of the spine has gained attention in the field of spinal deformity surgery for decades. However, emerging data support the importance of restoring segmental lumbar lordosis and lumbar spinal shape according to the pelvic morphology when surgically addressing degenerative lumbar pathologies such as degenerative disc disease and spondylolisthesis.➤ The distribution of caudal lordosis (L4-S1) and cranial lordosis (L1-L4) as a percentage of global lordosis varies by pelvic incidence (PI), with cephalad lordosis increasing its contribution to total lordosis as PI increases.➤ Spinal fusion may lead to iatrogenic deformity if performed without attention to lordosis magnitude and location in the lumbar spine.➤ A solid foundation of knowledge with regard to optimal spinal sagittal alignment is beneficial when performing lumbar spinal surgery, and thoughtful planning and execution of lumbar fusions with a focus on alignment may improve patient outcomes.

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.

Failed Back Surgery Syndrome: No Longer a Surgeon's Defeat-A Narrative Review

The introduction of the term Persistent Spinal Pain Syndrome (PSPS-T1/2), replacing the older term Failed Back Surgery Syndrome (FBSS), has significantly influenced our approach to diagnosing and treating post-surgical spinal pain. This comprehensive review discusses this change and its effects on patient care. Various diagnostic methods are employed to elucidate the underlying causes of back pain, and this information is critical in guiding treatment decisions. The management of PSPS-T1/2 involves both causative treatments, which directly address the root cause of pain, and symptomatic treatments, which focus on managing the symptoms of pain and improving overall function. The importance of a multidisciplinary and holistic approach is emphasized in the treatment of PSPS-T1/2. This approach is patient-centered and treatment plans are customized to individual patient needs and circumstances. The review concludes with a reflection on the impact of the new PSPS nomenclature on the perception and management of post-surgical spinal pain.

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.

Comparison of sagittal spinal alignment on standing plain x-rays and supine MRI in degenerative lumbar disease

Background

The purpose of the present study is to examine the possible correlation between standing plain x-rays and supine magnetic resonance imaging (MRI) for evaluating spinal sagittal alignment in degenerative lumbar disease (DLD).

Methods

The characteristics and images of 64 patients with DLD were reviewed retrospectively. The thoracolumbar junction kyphosis (TJK), lumbar lordosis (LL) and sacral slope (SS) were measured on lateral plain x-rays and by MRI. Inter- and intra-observer reliability was tested using intra-class correlation coefficients.

Results

The results suggested that TJK measurements obtained from MRI tended to underestimate the radiographic measures by 2°, whereas SS measurements obtained from MRI tended to overestimate the radiographic measures by 2°. The LL measurements obtained from MRI were approximately equal to the radiographic measures, and the x-ray and MRI measurements were linearly related.

Conclusions

In conclusion, supine MRI can be directly translated into sagittal alignment angle measurements obtained from standing x-rays with an acceptable degree of accuracy. This can avoid the impaired view caused by the overlapping ilium, while reducing the patient's exposure to radiation.

Association between Roussouly classification and characteristics of lumbar degeneration

OBJECTIVE

Different sagittal morphologies are associated with various lumbar degenerative diseases. In this paper, we aim to investigate the association between Roussouly classification and the characteristics of lumbar degeneration.

METHODS

A total of 273 patients with lumbar degeneration diseases were included in this cross-sectional study. The patients were divided into four groups according to the Roussouly classification. The degeneration of intervertebral disc (IVD) and facet joint was evaluated by Pfirrmann and Pathria grading scales, respectively. To elucidate the degenerative characteristics of diverse lumbar sagittal morphologies by comparing the degeneration degree of IVDs and facet joints between four groups.

RESULTS

The differences in sacral slope (SS) and lumbar lordosis (LL) were significant between the four groups (P < 0.05). Type 2 lumbar spine had the highest proportion of high-grade disc degeneration compared with other subtypes (P < 0.05), types 1 and 2 had a higher proportion of high-grade degeneration than types 3 and 4 (P < 0.05). However, type 4 lumbar spine had the highest proportion of high-grade facet joint degeneration compared with other subtypes (P < 0.05), types 3 and 4 had a higher proportion of high-grade degeneration than types 1 and 2 (P < 0.05).

CONCLUSIONS

Risks of advanced disc degeneration are higher for subjects with lumbar spine morphologies of Roussouly type 1 or type 2, especially for subjects with type 2 lumbar spine. Whereas, high-grade degeneration of facet joint tends to occur in type 3 and type 4 lumbar spine, especially for subjects with type 4 lumbar spine.

Early results of full-endoscopic decompression of lumbar central canal stenosis by outside-in technique: A clinical and radiographic study

Retrospective cohort study.Full-endoscopic decompression of lumbar spinal canal stenosis is being performed by endoscopic surgeons as an alternative to micro-lumbar decompression in the recent years. The outcomes of the procedure are reported by few authors only. The aim of this paper is to report the clinical and radiographic outcomes of full endoscopic lumbar decompression of central canal stenosis by outside-in technique at 1-year follow-up.We reviewed patients operated for lumbar central canal stenosis by full endoscopic decompression from May 2018 to November 2018. We analyzed the visual analogue scale scores for back and leg pain and Oswestry disability index at pre-op, post-op, and 1-year follow-up. At the same periods, we also evaluated disc height, segmental lordosis, whole lumbar lordosis on standing X-rays and canal cross sectional area at the affected level and at the adjacent levels on magnetic resonance imaging and the facet length and facet cross-sectional area on computed tomography scans. The degree of stenosis was judged by Schizas grading and the outcome at final follow-up was evaluated by MacNab criteria.We analyzed 32 patients with 43 levels (M:F = 14:18) with an average age of 63 (±11) years. The visual analogue scale back and leg improved from 5.4 (±1.3) and 7.8 (±2.3) to 1.6 (±0.5) and 1.4 (±1.2), respectively, and Oswestry disability index improved from 58.9 (±11.2) to 28 (±5.4) at 1-year follow-up. The average operative time per level was 50 (±16.2) minutes. The canal cross sectional area, on magnetic resonance imaging, improved from 85.78 mm2 (±28.45) to 150.5 mm2 (±38.66). The lumbar lordosis and segmental lordosis also improved significantly. The disc height was maintained in the postoperative period. All the radiographic improvements were maintained at 1-year follow-up. The MacNab criteria was excellent in 18 (56%), good in 11 (34%), and fair in 3 (9%) patients. None of the patients required conversion to open surgery or a revision surgery at follow-up. There was 1 patient with dural tear that was sealed with fibrin sealant patch endoscopically. There were 10 patients who had grade I stable listhesis preoperatively that did not progress at follow-up. No other complications like infection, hematoma formations etc. were observed in any patient.Full endoscopic outside-in decompression method is a safe and effective option for lumbar central canal stenosis with advantages of minimal invasive technique.

Characteristics of the sagittal spinal balance in the asymptomatic elderly Chinese population

PURPOSE

To investigate the normal values of the sagittal spinal parameters and analyze the distribution of the global spinal profiles in a Chinese population with age over 75.

METHODS

Two hundred and twelve sets of the whole spine lateral radiographs were obtained from a database of an asymptomatic elderly population. Global and regional spinal parameters were measured. Sagittal profiles were determined according to the Roussouly classification compared with previous studies involving different populations.

RESULTS

A total of 102 elderly subjects (≥ 75 years) were enrolled with an average age of 79.24 ± 3.53 years. The mean values of the spinopelvic parameters were 42.89 ± 11.64° for TK, 13.84 ± 10.78° for TLK, 44.48 ± 12.88° for LL, 44.76 ± 9.84° for PI, 17.19 ± 8.08° for PT, 28.35 ± 7.94° for SS, 3.47 ± 3.56 cm for SVA, 14.75 ± 7.85° for TPA, -0.27 ± 11.95° for PI-LL, respectively. Subjects ≥ 75 years were found to have significantly smaller LL and SS, but greater TLK, PT, SVA, TPA, and PI-LL than those 60-74 years (p < 0.05). Significant age- and sex-dependent differences were found in the Roussouly classification's distribution between the two subgroups.

CONCLUSIONS

The normal values of the sagittal parameters were presented in the elderly Chinese asymptomatic population (≥ 75 years). Ethnic, age, and sex displayed significant effects on the behaviors of the sagittal spinal balance and profiles. These results could be served as physiological references for the planning of surgical strategies in elderly Chinese patients over 75 years.

Correlation between thoracolumbar disc degeneration and anatomical spinopelvic parameters in supine position on MRI

Objective

This study aims to investigate the correlation between spinopelvic parameters in supine position (pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL)), disc degeneration and herniation of the thoracolumbar spine, as well as cardiovascular risk factors and back pain in a southern German cohort from the general population.

Methods

This study is a cross-sectional, case–control study drawn from a prospective cohort of the “Cooperative Health Research in the Region of Augsburg/Kooperative Gesundheitsforschung in der Region Augsburg” study (KORA). In total, 374 participants (mean age 56.4 ± 9.2 years; 57.8% male) from the whole-body MRI cohort (FF4) were included. All participants underwent a standardized whole-body MRI on which disc degeneration of the thoracic and lumbar spine was evaluated using a sequence adapted Pfirrmann score. PI, PT, SS and LL were measured according to the description in the literature, using sagittal imaging. Furthermore, disc bulging and protrusion were assessed. Correlations were estimated by logistic regression models providing odds ratios.

Results

Mean PI was 54.0° ± 11.1°, PT 13.0° ± 5.8°, SS 40.2° ± 8.8° and LL 36.2° ± 9.6°. SS was greater in men (p<0.05) and lumbar lordosis in women (p<0.001). PT increased by 0.09° per age-year with rising age. Age was not associated with PI, SS and LL. Neither BMI, hypertension, cholesterol, lipid levels, nor physical activity were associated with PI, PT, SS or LL. Diabetes mellitus negatively correlated with SS (β = -4.19; 95%CI -7.31–1.06, p<0.01). Smaller spinopelvic parameters (PI, SS and LL) where significantly (p<0.05) correlated with an increased frequency of disc bulging, as well as a local clustering in the lumbar, but not the thoracic spine.

Conclusion

In conclusion, spinopelvic parameters, measured in supine position, are significantly correlated with disc bulging alone; there is no significant correlation between supine spinopelvic parameters and disc degeneration, back pain or cardiovascular risk factors.

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.

Association between fatty infiltration of paraspinal muscle, sagittal spinopelvic alignment and stenosis grade in patients with degenerative lumbar spinal stenosis

Introduction

Sagittal balance and fatty infiltration of paraspinal muscle are important factors in patients with lumbar spinal stenosis (LSS) that may affect patients’ quality of life. Sagittal spinopelvic parameters and fatty infiltration may be associated with the severity of LSS. The purpose of this study was to test the hypothesis that severity of fatty infiltration correlates with severity of LSS and with sagittal pelvic alignment independent of age.

Methods

Age and body mass index (BMI) were extracted. Fatty infiltration was rated according to Goutallier classification and the severity of LSS was graded according to Schizas at five intervertebral disc levels. Overall fatty infiltration was computed as average fatty infiltration (aFI) and severity of LSS was defined as the highest severity of LSS of all segments. The sagittal spinopelvic parameters pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL) and PI-LL were measured. Associations among parameters were assessed using Spearman correlation coefficients adjusted for age (α = 0.05).

Results

165 LSS patients with a median age of 69 years were included. All parameters correlated with age (R>0.162, P<0.05) except BMI and LL (R<0.007, P>0.05). aFI correlated with PI, PT and PI-LL before (R>0.371, P<0.05) and after (R>0.180, P<0.05) adjusting for age. Severity of LSS correlated with PI, PT and PI-LL before (R>0.187, P<0.05) but not after (R<0.130, P>0.05) adjusting for age. aFI correlated with severity of LSS before (R=0.349, P<0.05) but not (R=0.114, P>0.05) after adjusting for age.

Conclusions

The correlation of aFI with sagittal spinopelvic parameters indicates that there might be a relationship between muscle characteristics and the sagittal alignment. Sagittal spinopelvic parameters and fatty infiltration of paraspinal muscles are not associated with radiological severity of LSS. Whether they are associated with clinical manifestation of LSS remains to be investigated.

Analysis of sagittal profile and radiographic parameters in symptomatic thoracolumbar disc herniation patients

BACKGROUND

Few studies describe thoracolumbar disc herniation (TLDH) as an isolated category, it is frequently classified as the lower thoracic spine or upper lumbar spine. Thus, less is known about the morphology and aetiology of TLDH compared to lumbar disc herniation (LDH). The aim of study is to investigate sagittal alignment in TLDH and analyze sagittal profile with radiographic parameters.

METHODS

Data from 70 patients diagnosed with TLDH were retrospectively reviewed. The thoracic-lumbar alignment was depicted by description of curvatures (the apex of lumbar curvature, the apex of thoracic curvature, and inflexion point of the two curvatures) and radiographic parameters from complete standing long-cassette spine radiographs. The rank sum test was utilised to compare radiographic parameter values in each subtype.

RESULTS

We found two subtypes differentiated by the apex of thoracic kyphotic curves. The sagittal profile was similar to that of the normal population in type I, presenting the apex of the thoracic kyphotic curve located in the middle thoracic spine. The well aligned thoracic-lumbar curve was disrupted in type II, presenting the apex of the thoracic kyphotic curve located in the thoracolumbar region in type II patients. Thirty-six patients were classified as type I, and 34 patients were classified as type II. The mean sagittal vertical axis, T1 pelvic angle and L1 pelvic angle were 27.9 ± 24.8°, 8.2 ± 7.3° and 6.2 ± 4.9°, respectively. There was significant difference (p < 0.001) of thoracolumbar angle between type I (14.9 ± 7.9°) and type II patients (29.1 ± 13.7°).

CONCLUSIONS

We presented two distinctive sagittal profiles in TLDH patients, and a regional kyphotic deformity with a balanced spine was validated in both subtypes. In type I patients, disc degeneration was accelerated by regional kyphosis in the thoracolumbar junction and eventually caused disc herniation. In type II patients, excessive mechanical stress was directly loaded at the top of the curve (thoracolumbar apex region) rather than being diverted by an arc as in a normal population or type I patients. Mismatch between shape and sacral slope value was observed, and better agreement was found in Type II patients.

Revision Surgery Rates After Minimally Invasive Adult Spinal Deformity Surgery: Correlation with Roussouly Spine Type at 2-Year Follow-Up?

BACKGROUND

Spinopelvic parameters have hitherto dictated much of adult spinal deformity (ASD) correction. The Roussouly classification is used for the normal adult spine. We evaluated whether a correlation would be found between the Roussouly type and the rate of revision surgery in patients with ASD undergoing circumferential minimally invasive spinal (cMIS) correction.

METHODS

A multicenter retrospective review of patients who had undergone cMIS surgery for ASD was performed. The inclusion criteria were age ≥18 years and 1 of the following: coronal Cobb angle >20°, sagittal vertical axis >5 cm, pelvic tilt >20°, pelvic incidence (PI) to lumbar lordosis (LL) mismatch >10°, cMIS surgery, and a minimum of 2 years of follow-up data available. The patients were classified by Roussouly type, and the clinical and radiographic outcomes were evaluated.

RESULTS

A total of 104 patients were included in the present analysis. Of the 104 patients, 41 had Roussouly type 1, 32 had type 2, 23 had type 3, and 8 had type 4. Preoperatively, the patients with type 4 had the highest PI (P = 0.002) and LL (P < 0.001). Postoperatively, the PI-LL mismatch, Cobb angle, and sagittal vertical axis were not different among the 4 groups. However, the patients with type 2 had had the highest rate of complications (type 1, 29.3%; type 2, 61.3%; type 3, 34.8%; type 4, 25.0%; P = 0.031). The reoperation rates were comparable (type 1, 19.5%; type 2, 38.7%; type 3, 13.0%; type 4, 12.5%; P = 0.097). The reoperation rates for adjacent segment degeneration or proximal junctional kyphosis were also comparable (P = 0.204 and P = 0.060, respectively).

CONCLUSIONS

We did not find a clear correlation between Roussouly type and the rate of revision surgery for adjacent segment disease or proximal junctional kyphosis in patients who had undergone cMIS surgery for ASD.

Lumbar degenerative disease after oblique lateral interbody fusion: sagittal spinopelvic alignment and its impact on low back pain

Background

We determined the incidence and risk factors of low back pain (LBP) in patients with lumbar degenerative disease after single-level oblique lateral interbody fusion (OLIF).

Methods

We retrospectively reviewed 120 lumbar degenerative disease patients who underwent single-level OLIF. We compared preoperative and postoperative radiographic parameters, including segmental lordosis (SL), lumbar lordosis (LL), disk height (DH), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), thoracic kyphosis (TK), and C7-sagittal vertical axis (SVA). Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) scores and visual analog scale (VAS) scores for back and leg pain. All patients were followed up for at least 2 years.

Results

Thirty-eight patients had postoperative LBP (VAS score for back pain ≥3; LBP group); the remaining 82 patients were in the non-LBP group. Age (P = 0.082), gender (P = 0.425), body mass index (P = 0.138), diagnosis (degenerative spondylolisthesis vs. lumbar spinal stenosis; P = 0.529), surgical level (P = 0.651), blood loss (P = 0.889), and operative time (P = 0.731) did not differ between the groups. In both groups, the ODI and VAS scores for back pain and leg pain significantly improved at the final follow-up compared with the preoperative scores (P = 0.003). Except for the VAS score for back pain (P = 0.000), none of the scores significantly differed between the two groups at the final follow-up (P > 0.05). In the non-LBP group, LL, SL, DH, TK, and SS significantly improved, while PT and C7-SVA significantly decreased at the final follow-up as compared with the preoperative values. In both groups, DH significantly improved postoperatively, with no significant between-group difference (P = 0.325). At the final follow-up, LL, PI-LL mismatch, PT, and C7-SVA showed significantly greater improvement in the non-LBP group than in the LBP group (P < 0.05). Multivariate analysis identified PT, PI-LL mismatch, and C7-SVA as significant risk factors for LBP after OLIF.

Conclusion

OLIF for single-level lumbar degenerative disease had satisfactory clinical outcomes. PT, PI-LL mismatch, and C7-SVA were significant risk factors for postoperative LBP. Patients with appropriately decreased PT, improved C7-SVA, and PI-LL match experienced less LBP.

Straighter low lumbar curvature in isthmic spondylolisthesis at L4

BACKGROUND

This study was conducted to compare differences in imaging features and clinical symptoms between patients with single-level isthmic spondylolisthesis (IS) at L4 and at L5 and to investigate the correlation between imaging and clinical parameters.

METHODS

This cross-sectional study evaluated patients with single-level IS who were enrolled between June 2011 and June 2018. A total of 139 patients, 44 in the L4 IS group and 95 in the L5 IS group, met the study criteria and were included. Imaging and clinical parameters obtained from the two groups were compared and analyzed.

RESULTS

Patients in the L4 IS group had smaller lower lumbar lordosis (LLL) (27.1 ± 8.2 vs. 30.9 ± 9.3, P = 0.021) and were of older age (58.5 ± 8.7 vs. 52.8 ± 10.1, P < 0.01) than those in the L5 IS group. As per the Roussouly classification system, most patients with L4 IS were classified as Type 2 (43.2%), whereas most patients with L5 IS fell under Type 3 (44.2%). In the L5 IS group, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), and L5 incidence (L5I) were positively associated with slippage rate (SR), but the lumbosacral angle (LSA) was negatively associated with SR (P < 0.01). In the L4 IS group, only L5I showed a positive association with SR (P < 0.01). More significant associations were found among sagittal lumbo-pelvic parameters in the L5 IS group, but none were found between SR and Oswestry Disability Index (ODI) in either group.

CONCLUSIONS

When compared with patients with L5 IS, patients with L4 IS were of older age and had straighter low lumbar curvature when they were obviously symptomatic. PI was an important parameter for patients with L5 IS while for those with L4 IS, L5I deserved more attention for its significantly positive correlation with the degree of slippage.