Pelvic Incidence-lumbar Lordosis Mismatch Research Articles

Head and pelvis are the key segments recruited by adult spinal deformity patients during daily life activities

Functional assessment is a key element in evaluating adult spinal deformity (ASD) patients. The multitude of 3D kinematic parameters provided by movement analysis can be confusing for spine surgeons. The aim was to investigate movement patterns of ASD based on key kinematic parameters. 115 primary ASD and 36 controls underwent biplanar radiographs and 3D movement analysis during walking, sit-to-stand and stair ascent to calculate joint and segment kinematics. Principal component analysis was applied to identify the most relevant kinematic parameters that define movement strategies adopted by ASD. Pelvis and head relative to pelvis kinematics were the most relevant parameters. ASD patients adopted four different movement strategies. Class 1: normative head and pelvis kinematics. Class 2: persistent pelvic backward tilt. Class 3: persistent forward shift of the head. Class 4: both pelvic backward tilt and forward shift of the head. Patients in class 3 and 4 presented sagittal malalignment on static radiographs with increased pelvic tilt, pelvic incidence-lumbar lordosis mismatch and sagittal vertical axis. Surprisingly, patients in class 3 had normal pelvic kinematics during movement, showing the importance of functional evaluation. In addition to being key segments in maintaining static global posture, head and pelvis were found to define movement patterns.

Mismatch Between Pelvic Incidence and Lumbar Lordosis After Personalized Interbody Fusion: The Importance of Preoperative Planning and Alignment in Degenerative Spine Diseases.

Emerging data have highlighted the significance of planning and aligning total and segmental lumbar lordosis with pelvic morphology when performing short-segment fusion with the goal of reducing the risk of adjacent segment disease while also decreasing spine-related disability. This study evaluates the impact of personalized interbody implants in restoring pelvic incidence-lumbar lordosis (PI-LL) mismatch compared with a similar study using stock interbody implants. This multicenter retrospective analysis assessed radiographic pre- and postoperative spinopelvic alignment (PI-LL) in patients who underwent 1- or 2-level lumbar fusions with personalized interbody implants for degenerative (nondeformity) indications. The aim was to assess the incidence of malalignment (PI-LL ≥ 10°) both before and after fusion surgery and to determine the rate of alignment preservation and/or correction in this population. There were 135 patients included in this study. Of 83 patients who were aligned preoperatively, alignment was preserved in 76 (91.6%) and worsened in 7 (8.4%). Among the 52 preoperatively malaligned patients, alignment was restored in 23 (44.2%), and 29 (55.8%) were not fully corrected. Among patients who were preoperatively aligned, there was no statistically significant difference in either the "preserved" or "worsened" groups between stock devices and personalized interbody devices. In contrast, among patients who were preoperatively malaligned, there was a statistically significant increase in the "restored" group (P = 0.046) and a statistically significant decrease in the "worsened" groups in patients with personalized interbodies compared with historical stock device data (P < 0.05). Compared with a historical cohort with stock implants, personalized interbody implants in short-segment fusions have shown a statistically significant improvement in restoring patients to normative PI-LL. Using 3-dimensional preoperative planning combined with personalized implants provides an important tool for planning and achieving improvement in spinopelvic parameters.

Durability of substantial clinical benefit leading to optimal outcomes in adult spinal deformity corrective surgery: a minimum 5-year analysis.

The objective was to evaluate factors associated with the long-term durability of outcomes in adult spinal deformity (ASD) patients. Operative ASD patients fused from at least L1 to the sacrum with baseline (BL) to 5-year (5Y) follow-up were included. Substantial clinical benefit (SCB) in Oswestry Disability Index (ODI), numeric rating scale (NRS)-back, NRS-leg, and Scoliosis Research Society (SRS)-22r scores and physical component score were assessed on the basis of previously published values. Factors were evaluated on the basis of meeting optimal outcomes (OO) at 2 years (2+) and 5 years (5+). Furthermore, 2+ patients were isolated and evaluated on the basis of meeting OO at 5 years (2+5+) or not at 5 years (2+5-). OO were defined as follows: no reoperation, major mechanical failure, proximal junctional failure, and meeting either 1) SCB in terms of ODI score (decrease > 18.8) or 2) ODI < 15 and SRS-22r total > 4.5. In total, 330 ASD patients met the inclusion criteria, with 45.5% meeting SCB for ODI at 2 years, while 46.0% met SCB at 5 years; 79% of those who achieved 2-year (2Y) SCB went on to achieve 5Y SCB. This rate was lower for OO, with 41% achieving 2Y OO (2+), while 37% met 5Y OO (5+) and 80% of 2+ patients had durable outcomes until 5+ (32% of the total cohort). Of the patient factors, frailty was significantly different among groups at 2 years, while comorbidity burden was significantly different at 5 years and the combination thereof differed in those with durable outcomes. Those who regained their level of activity postoperatively had 4 times higher odds of maintaining OO from 2 years to 5 years (p < 0.05). Osteoporosis rates, although equivocal at BL, were higher at the last follow-up in those who met 2Y OO but failed to meet 5Y OO. The odds of achieving OO at 5 years in 2+ patients decreased by 47% for each additional comorbidity and decreased by 74% in those who had lower-extremity paresthesias at BL (both p < 0.05). Controlling for patient factors and BL disability found fewer levels fused, decreased correction of sagittal vertical axis, and increased correction of pelvic incidence-lumbar lordosis mismatch to be predictive of maintaining 2Y OO until 5 years (p < 0.05). SCB was met in 46% of ASD patients at 5 years. The durability of OO was seen in a third of patients until 5 years postoperatively. Higher rates of medical complications were seen in those who failed to achieve and maintain OO until 5 years. Frailty and comorbidity burden were significant factors associated with the achievement and durability of OO until 5 years.

Pelvic Incidence–Lumbar Lordosis Mismatch Is Not Associated with Early Reoperation for Adjacent Segment Disease After Lumbar Fusion

Study DesignRetrospective Cohort Study ObjectivesTo compare the 2-year reoperation rates for adjacent segment disease between patients with pelvic incidence-lumbar lordosis (PI-LL) mismatch postoperatively and patients with normal PI-LL measurements. MethodsPatients undergoing elective 1-to-2 level lumbar fusion for degenerative conditions between 2016-2018 were retrospectively reviewed. Spinopelvic radiographic parameters immediately post-operation were measured and PI-LL mismatch was determined using the age-adjusted thresholds defined in Lafage et al. Following propensity score matching, early reoperation rates were compared between the PI-LL mismatch and normal PI-LL cohorts. Early reoperation was defined as symptomatic adjacent segment disease (ASD) requiring reoperation within 2 years of the index surgery. ResultsA total of 219 patients were identified. The average age was 59 years old with 59.8% female. The PI-LL mismatch cohort (N=148) were younger (57.5 vs. 63.5, p<0.001) and had a higher proportion of black patients (31.8% vs. 11.3%, p=0.001) compared to the normal PI-LL cohort. A total of 100 patients in the PI-LL mismatch cohort were propensity score matched to 66 patients in the normal PI-LL cohort, resulting in no difference in age (p=0.177), sex (p=0.302), race (p=0.727), or BMI (p=0.892). Using these matched cohorts, the rate of early reoperation for ASD was 8.0 % in the PI-LL mismatch cohort and 9.1% in the normal PI-LL cohort (p=0.805) with a mean time to reoperation of 1.28 and 1.33 years, respectively. ConclusionsAfter propensity score matching, PI-LL mismatch was not associated with early reoperation for ASD in patients undergoing 1-to-2 level lumbar fusions for degenerative conditions.

Does global spinal alignment affect the use of walking aids after multi-segment spinal fixation for patients with ASD? A multicenter retrospective study.

This study aimed to clarify the relation between global spinal alignment and the necessity of walking aid use in patients with adult spinal deformity (ASD) and to investigate the impact of spinal fixation on mobility status after surgery. In total, 456 older patients with ASD who had multi-segment spinal fixation surgery and were registered in a multi-center database were investigated. Patients under 60years of age and those unable to walk preoperatively were excluded. Patients were classified by their mobility status into the independent, cane, and walker groups. Comparison analysis was conducted using radiographic spinopelvic parameters and the previously reported global spine balance (GSB) classification. In addition, preoperative and 2years postoperative mobility statuses were investigated. Of 261 patients analyzed, 66 used walking aids (canes, 46; walkers, 20). Analysis of preoperative radiographical parameters showed increased pelvic incidence and pelvic incidence-lumbar lordosis mismatch in the walker group and increased sagittal vertebral axis in the cane and walker groups versus the independent group. Analysis of GSB classification showed a higher percentage of walker use in those with severe imbalance (grade 3) in the sagittal classification but not in the coronal classification. While postoperative radiographical improvements were noted, there was no significant difference in the use of walking aids before and 2years after surgery (P = 0.085). A significant correlation was found between "sagittal" spinal imbalance and increased reliance on walking aids, particularly walkers. However, the limitation of improvement in postoperative mobility status suggested that multiple factors influence the mobility ability of elderly patients with ASD.

The Role of L1PA in Patient-reported Outcomes in Patients Undergoing Single-level Lumbar Fusion for Degenerative Spondylolisthesis.

Retrospective cohort study. To determine whether the L1 pelvic angle (L1PA) can be used to predict quality of life outcomes for adults one year after L4-L5 fusion to treat degenerative spondylolisthesis. L1PA is beneficial in the evaluation of preoperative and postoperative quality of life outcomes in patients undergoing surgery for spinal deformity. No studies have examined its utility in surgical patients with degenerative spinal disease. Patients undergoing L4-L5 posterolateral decompression and fusion or transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis were grouped by preoperative and postoperative L1PA, and further stratified by cut offs of >7.2° and <7.2° based on previous literature. We also stratified patients by presence of an ideal calculated L1PA, defined as (0.5×Pelvic incidence) -21 +/-5°, as proposed by prior literature. Preoperative, one-year postoperative and Δ (postoperative minus preoperative) patient-reported outcome measures (PROMs) and radiographic measurements were collected. Twenty-four patients were identified with preoperative L1PAs <7.2° and 132 with L1PAs >7.2°. Eighteen patients were identified with postoperative L1PAs <7.2° and 138 with L1PAs>7.2°. Sixty-five and fifty-seven patients were identified as having ideal calculated preoperative and postoperative L1PAs, respectively. When using absolute cutoffs, L1PA correlated with pelvic tilt, pelvic incidence, and pelvic incidence-lumbar lordosis mismatch (PI-LL). When using calculated L1PAs, L1PA correlated with lumbar lordosis, PI-LL, pelvic tilt and sacral slope. With respect to PROMs, no statistically significant differences existed between cohorts both preoperatively and at one-year postoperatively on either univariate and multivariate analyses. L1PA may be a helpful radiographic consideration that translates to clinically relevant outcomes in spinal deformity. However, it does not appear as predictive of patient outcomes after single-level fusion for patients with L4-L5 degenerative spondylolisthesis. Further studies are warranted to investigate the role of L1PA in degenerative spine patients.

The Incremental Clinical Benefit of Adding Layers of Complexity to the Planning and Execution of Adult Spinal Deformity Corrective Surgery.

For patients with surgical adult spinal deformity (ASD), our understanding of alignment has evolved, especially in the last 20 years. Determination of optimal restoration of alignment and spinal shape has been increasingly studied, yet the assessment of how these alignment schematics have incrementally added benefit to outcomes remains to be evaluated. Patients with ASD with baseline and 2-year were included, classified by 4 alignment measures: Scoliosis Research Society (SRS)-Schwab, Age-Adjusted, Roussouly, and Global Alignment and Proportion (GAP). The incremental benefits of alignment schemas were assessed in chronological order as our understanding of optimal alignment progressed. Alignment was considered improved from baseline based on SRS-Schwab 0 or decrease in severity, Age-Adjusted ideal match, Roussouly current (based on sacral slope) matching theoretical (pelvic incidence-based), and decrease in proportion. Patients separated into 4 first improving in SRS-Schwab at 2-year, second Schwab improvement and matching Age-Adjusted, third two prior with Roussouly, and fourth improvement in all four. Comparison was accomplished with means comparison tests and χ2 analyses. Sevenhundredthirty-two. patients met inclusion. SRS-Schwab BL: pelvic incidence-lumbar lordosis mismatch (++:32.9%), sagittal vertical axis (++: 23%), pelvic tilt (++:24.6%). 640 (87.4%) met criteria for first, 517 (70.6%) second, 176 (24%) third, and 55 (7.5%) fourth. The addition of Roussouly (third) resulted in lower rates of mechanical complications and proximal junctional kyphosis (48.3%) and higher rates of meeting minimal clinically important difference (MCID) for physical component summary and SRS-Mental (P < .05) compared with the second. Fourth compared with the third had higher rates of MCID for ODI (44.2% vs third: 28.3%, P = .011) and SRS-Appearance (70.6% vs 44.8%, P < .001). Mechanical complications and proximal junctional kyphosis were lower with the addition of Roussouly (P = .024), while the addition of GAP had higher rates of meeting MCID for SRS-22 Appearance (P = .002) and Oswestry Disability Index (P = .085). Our evaluation of the incremental benefit that alignment schemas have provided in ASD corrective surgery suggests that the addition of Roussouly provided the greatest reduction in mechanical complications, while the incorporation of GAP provided the most significant improvement in patient-reported outcomes.

L1 slope: an overlooked spinal parameter.

Lumbar lordosis can be divided into two parts by a horizontal line, creating the L1 slope and the sacral slope. Despite being a major spinopelvic parameter, the L1slope (L1S) is rarely reported. However, there is some evidence that L1S is a relatively constant parameter. This study aimed to analyze the L1 slope and its relationships with other spinopelvic parameters. Standing lateral lumbosacral x-ray radiographies of 76 patients with low back pain and CT scans of 116 asymptomatic subjects were evaluated for spinal and spinopelvic parameters including L1 slope (L1S). The x-ray and CT groups were divided into subgroups according to mean sacral slope (SS) or pelvic incidence (PI) values. The mean values of the spinopelvic parameters and the correlations between them were investigated and compared. L1S was 19.70 and 18.15 in low SS and high SS subgroups of x-ray respectively. L1S was 7.95 and 9.36 in low and high PI subgroups of CT, respectively, and the differences were insignificant statistically. L1S was the only spinal parameter that did not change as SS or PI increased in standing and supine positions. L1S was correlated with lumbar lordosis (LL) proximal lumbar lordosis (PLL) and distal lumbar lordosis (DLL) in both x-ray and CT groups. L1S was also the strongest correlated parameter with pelvic incidence lumbar lordosis mismatch (PI-LL) mismatch in supine position. L1S is a relatively constant parameter and is around 16°-18° and 8°-9° in the standing and supine positions, respectively. It was significantly correlated with LL, PLL, DLL, and PI-LL. In the standing position it was nearly equal to PLL while this equality was present in low PI subgroups of CT. There is strong evidence that L1S is significantly correlated with health-related quality of life scores.

Sagittal spinopelvic alignment in ambulatory persons with cerebral palsy.

This study aimed to describe the spinopelvic alignment of a cohort of young ambulatory individuals with cerebral palsy (CP) and compare it to published spinopelvic alignment data for the typically developing adolescents. Thirty-seven adolescents (18 females) with CP at GMFCS I-III were included in this retrospective case series. Lumbar lordosis and pelvic incidence were measured, and their mismatch was calculated. A model that calculates predicted lumbar lordosis based on pelvic incidence in normative data was utilized to calculate a predicted lumbar lordosis in this cohort with cerebral palsy. At imaging, ages were mean and standard deviation 13.5 ± 3.0years. Pelvic incidence was 46.2° ± 12.9°, pelvic tilt was 2.8° ± 9.4°, sacral slope was 43.6° ± 10.8°, and measured lumbar lordosis was 59.4° ± 11.6°. There were no differences in pelvic incidence or lumbar lordosis among the GMFCS levels; however, pelvic incidence was higher in females. Pelvic incidence-lumbar lordosis mismatch greater than 10° was found in 67% of the cohort. Mean predicted lumbar lordosis based on the model was 54.7° ± 8.5°, averaging 8° less than measured lordosis. PI-LL mismatch was identified in 67% of this cohort of ambulatory adolescents with CP, in part due to greater lordosis than predicted by a model based on data from adolescents without CP. The implications of this finding, such as the correlation between sagittal spinopelvic alignment and quality of life in this population, should be assessed further in ambulatory patients with cerebral palsy. Level IV-retrospective cohort study and literature comparison.

287 What is the Velocity of Return-to-work After Circumferential Minimally-Invasive Surgery Versus Open Correction for Adult Spinal Deformity?

INTRODUCTION: While faster recovery is a touted benefit of minimally-invasive spinal operations, these differences have been poorly described for return-to-work after larger fusion constructs for adult spinal deformity. METHODS: Adult spinal deformity (ASD) patients =18 yr were queried from a multicenter, prospective database across the USA. To ensure equal cohorts for comparing the impact of MIS vs. open correction technique, propensity score matched gender, age, BMI, pelvic incidence-lumbar lordosis mismatch, and sagittal vertical axis. Of 190 patients with baseline surveys, 173 respondents (91.0%) had both baseline employment and 2-year follow-up. The open and cMIS cohorts were compared with a chi-squared test. The rate of return-to-work was calculated via discrete-time proportional hazards model—reporting an adjusted odds ratio (ORadj)—at three follow-up intervals: 6 weeks, 1-year, and 2-years. RESULTS: Of 173 patients, baseline employment status was nearly equal between open (n = 85) vs cMIS (n = 88) cohorts: employed (20.0% vs 21.5%), unemployed (3.5% vs 4.5%), disabled (4.7% vs 6.8%), and retired (71.7% vs 67.0%) (p = 0.888). The number of employed patients between the open vs cMIS cohort statistically significantly differed at 1-year (10.5% vs 21.5%, p = 0.049), but not at 6 weeks (14.1% vs 15.9%, p = 0.741) or 2-years (14.1% vs 19.3%, p = 0.277). The velocity of return-to-work did not differ (OR = 1.2, p = 0.549). In a sub-analysis of 36 patients who were employed at baseline, the number of employed patients between the open vs cMIS cohort statistically significantly differed at 1-year (47.0% vs 89.4%, p = 0.006), but not at 6 weeks (70.5% vs 73.6%, p = 0.636) or 2-years (58.8% vs 78.9%, p = 0.191). The velocity of return-to-work was also similar (ORadj = 1.57, p = 0.481). CONCLUSIONS: Despite an equivalent baseline employment status, more patients in the cMIS cohort were employed at 1-year; however, there was no difference at 2-years. Similar trends were appreciated in a sub-analysis of patients who were employed at baseline.

Sagittal Profi le of the Spine in Patients after Lumbar Stabilisation Surgeries

Spine stabilization surgery is nowadays one of the most common spinal surgical procedures. Spinopelvic alignment is considered to be an important factor impacting the patients' preoperative diffi culties as well as the outcome of surgery. In our study, the outcomes of stabilization surgeries in patients with lumbar spine disorders were evaluated - especially in those with stenosis and spondylolisthesis, in whom the importance of sagittal parameters were assessed with respect to the patients' clinical outcomes and diffi culties. The study included 50 patients with lumbar spine disorders who had undergone a spine stabilization surgery for a degenerative disease - lumbar spinal stenosis, spondylolisthesis between 2015 and 2017. Spino-pelvic radiological parameters and clinical parameters were evaluated using the nonparametric Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests. In 38 of 50 patients, who at the end of the follow-up period did not have the PI-LL (pelvic incidence-lumbar lordosis) mismatch, i.e. PI-LL was ≤10°, a statistically signifi cant difference in pelvic tilt (p=0.049) and sagittal vertical axis (p<0.001) was reported, which was not the case in the remaining patients of the study population. Claudication and OSWESTRY (ODI) showed no statistically signifi cant difference. We have also compared the differences in the number of fused vertebrae and type of stabilization. A signifi cant change was seen in the claudication parameter at 12 and 24 months after surgery (p=0.007, p=0.005), with better outcomes achieved by 360° lumbar fusion compared to posterior lumbar fusion. The improvement of VAS and ODI scores in both the groups over time (from 6.1 to 3.6 or from 6.3 to 3.5 in VAS and from 62 to 32, or from 62 to 30 in ODI) was also statistically signifi cant (p<0.001 in both groups), while when comparing the groups against each other it was statistically insignifi cant. The authors confi rmed signifi cant improvement in the studied clinical parameters in all groups of patients (VAS, ODI, claudication), which is consistent with the results of recently published papers. The authors also established the correlation between different radiological parameters in the studied groups. The results do not confi rm the importance of the length or type of instrumentation for the clinical outcomes. This is consistent with the fi ndings of other published manuscripts. The authors failed to confi rm a signifi cant change in clinical parameters in dependence on the matching relationship between the pelvic incidence and lumbar lordosis. Proper spinopelvic balance in patients after spinal surgery is a very important indicator of postoperative development and condition, but our cohort showed no statistically signifi cant difference in the clinical outcomes of patients whose postoperative sagittal parameters were unsatisfactory. sagittal profi le, spine stabilization, pelvic tilt, pelvic incidence, sagittal vertical axis, SVA.

Effectiveness of a two-stage posterior-anterior–posterior surgery using subcutaneously preserved autologous bone grafts for adult spinal deformity: a retrospective observational study

BackgroundTo achieve optimal correction of rigid kyphoscoliosis, we developed a novel two-stage posterior-anterior–posterior (PAP) surgery using subcutaneously preserved autologous bone grafts. This study aimed to investigate the effectiveness of two-stage PAP surgery versus single-stage anterior–posterior (AP) surgery.MethodsThis was a retrospective analysis of patients undergoing combined anterior–posterior long-level fusion for adult spinal deformity (ASD) with a minimum 2-year follow-up. The indications for two-stage PAP surgery were rigid thoracolumbar deformity associated with hypertrophic facet arthritis and/or a large pelvic incidence–lumbar lordosis mismatch of > 25°. In the first stage of PAP surgery, pedicle screw insertion and multilevel Ponte osteotomies were performed. The resected local bone was embedded under sutured fascia. One week later, the embedded bone was retrieved in the right lateral position and used as an autograft for lateral lumbar interbody fusion. Final deformity correction was performed in the prone position.ResultsFrom January 2018 to April 2021, 12 and 16 patients with ASD underwent two-stage PAP surgery (PAP group) and single-stage AP surgery (AP group), respectively. Although PAP surgery was associated with a significantly longer operation time, the total blood loss volume was significantly less in the PAP group than the AP group. Compared with the AP group, the PAP group showed significantly larger postoperative changes in radiological parameters in the sagittal and coronal planes. The overall complication rate did not differ significantly between the two groups.ConclusionTwo-stage PAP surgery provided effective correction of rigid kyphoscoliosis without increasing blood loss and postoperative complication rates.

Three-column osteotomy in long constructs has lower rates of proximal junctional kyphosis and better restoration of lumbar lordosis than anterior column realignment.

Three-column osteotomies (TCOs) and minimally invasive techniques such as anterior column realignment (ACR) are powerful tools used to restore lumbar lordosis and sagittal alignment. We aimed to appraise the differences in construct and global spinal stability between TCOs and ACRs in long constructs. We identified consecutive patients who underwent a long construct lumbar or thoracolumbar fusion between January 2016 and November 2021. "Long construct" was any construct where the uppermost instrumented vertebra (UIV) was L2 or higher and the lowermost instrumented vertebra (LIV) was in the sacrum or ileum. We identified 69 patients; 14 (20.3%) developed PJK throughout follow-up (mean 838days). Female patients were less likely to suffer PJK (p = 0.009). TCO was more associated with open (versus minimally invasive) screw/rod placement, greater number of levels, higher UIV, greater rate of instrumentation to the ilium, and posterior (versus anterior) L5-S1 interbody placement versus the ACR cohort (p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.005, respectively). Patients who developed PJK were more likely to have undergone ACR (12 (32.4%) versus 2 (6.3%, p = 0.007)). The TCO cohort had better improvement of lumbar lordosis despite similar preoperative measurements (ACR: 16.8 ± 3.78°, TCO: 23.0 ± 5.02°, p = 0.046). Pelvic incidence-lumbar lordosis mismatch had greater improvement after TCO (ACR: 14.8 ± 4.02°, TCO: 21.5 ± 5.10°, p = 0.042). By multivariate analysis, ACR increased odds of PJK by 6.1-times (95% confidence interval: 1.20-31.2, p = 0.29). In patients with long constructs who undergo ACR or TCO, we experienced a 20% rate of PJK. TCO decreased PJK 6.1-times compared to ACR. TCO demonstrated greater improvement of some spinopelvic parameters.

Exploring the impact of mild-to-moderate foraminal stenosis at L5−S1 on clinical outcomes following L4−5 posterior lumbar interbody fusion

BACKGROUND CONTEXTPatients scheduled for L4−5 PLIF often have FS at L5-S1. However, data on the clinical and radiographic outcomes of cases with mild-to-moderate L5−S1 FS are lacking, which may affect clinical outcomes or require additional surgery after L4−5 fusion. PURPOSETo evaluate the clinical and radiographic outcomes of L4−5 PLIF in patients with and without mild-to-moderate L5−S1 FS, with a primary focus on the association between L5−S1 FS and postoperative clinical outcomes including back pain, leg pain, and scores on the oswestry disability index (ODI) and EuroQol 5-dimension (EQ-5D). STUDY DESIGNRetrospective comparative study. PATIENT SAMPLEA retrospective review of patients who underwent L4−5 PLIF from 2014 to 2018. The patients were divided according to the presence of mild-to-moderate FS at L5−S1. OUTCOME MEASURESClinical assessment included the pain visual analog scale (VAS), ODI, and EQ-5D score. Radiographic assessments included spinopelvic parameters and grades for central and foraminal stenosis. METHODSClinical outcomes were assessed using validated outcome measures at preoperative, 6-month, 12-month, and 36-month follow-up visits. Radiographic evaluations were performed using preoperative and postoperative radiographs. Foraminal stenosis was assessed qualitatively using MRI with a grading system from none to severe and quantitatively by measuring changes in the foraminal area on CT. RESULTSAmong 186 patients, 55 were categorized as the FS group and 131 as the non-FS group. The FS group was older (p=0.039) and had more severe central stenosis at L5−S1 (p=0.007) as well as more severe FS at both L4−5 and L5−S1 (both p<0.001). Preoperative disc height (p<0.001), C7-S1 sagittal vertical axis (p=0.003), lumbar lordosis (p=0.005), and pelvic incidence–lumbar lordosis mismatch (p=0.026) were more aggravated in the FS group. The FS group showed inferior clinical outcomes at the final follow-up in terms of back pain (p=.010) and ODI score (p=.003). CONCLUSIONThe presence of mild-to-moderate FS at L5–S1 was associated with more aggravated sagittal balance in terms of smaller preoperative disc height, larger sagittal vertical axis, smaller lumbar lordosis, and larger pelvic incidence–lumbar lordosis mismatch. Patients with L5−S1 FS also had poorer clinical outcomes including back pain and ODI score after L4−5 PLIF. Patients with L5−S1 FS need to be carefully examined before L4−5 fusion considering their adverse outcomes due to underlying degenerative changes.

Influence of Spinopelvic Alignment on the Clinical Outcomes Following Decompression Surgery for Lumbar Stenosis.

Introduction The role of sagittal spinopelvic alignment in lumbar spinal stenosis (LSS) patients and its potential influence on post-decompression surgery outcomes is a topic of growing interest. Lumbar spinal stenosis is a prevalent degenerative condition, and with an aging population, the frequency of surgical interventions for LSS has risen. While decompression surgery aims to relieve symptoms, the potential impact of preoperative spinopelvic alignment on postoperative results remains controversial. This study examined the correlation between sagittal spinopelvic parameters and clinical outcomes in LSS patients undergoing decompression surgery. Methods This study included 100 patients with LSS who underwent decompression surgery between 2021 and 2023 and 100 healthy individuals as a control group. The LSS group comprised 50 men and 50 women, with a mean age of 55.8±12.41 years, while the control group consisted of 50 men and 50 women, with a mean age of 55.17±13.39 years. Sagittal spinopelvic alignment parameters, including pelvic tilt (PT), pelvic incidence-lumbar lordosis mismatch, and sagittal vertical axis, were assessed preoperatively. Postoperative clinical outcomes were evaluated using the visual analog scale (VAS) and Oswestry disability index (ODI) scores. Results In the cohort of 200 participants, 100 were diagnosed with lumbar spinal stenosis (LSS), and 100 were healthy controls. Both groups had an equal gender distribution (50 males and 50 females). The mean age was 55.8 (±12.4) years for the LSS group and 55.2 (±13.4) years for the control group. Among the analyzed radiographic parameters, only lumbar lordosis (LL) levels showed a significant difference between groups, notably lower in the LSS group (p=0.020). Preoperative VAS scores in LSS patients averaged 7.58±1.32, which postoperatively dropped to 2.22±1.95 (p<0.001). Similarly, ODI (%) declined from a preoperative average of 55.76±11.65 to 18.62±18.17 postoperatively (p<0.001). Patients with postoperative ODI levels exceeding 20% had higher preoperative scores and significantly altered radiographic measurements. The receiver operating characteristic (ROC) analysis indicated PT as the most predictive radiographic parameter, with an area under the curve (AUC) of 0.945. Multivariate logistic regression pinpointed PT and LL as key predictors associated with increased risks for postoperative Oswestry disability levels exceeding 20%. Conclusion Our study suggests that sagittal spinopelvic alignment plays an important role in the development and progression of LSS. Addressing sagittal alignment may be crucial for achieving optimal clinical outcomes afterdecompression surgery. Further research is needed to elucidate the mechanisms underlying the relationship between sagittal alignment and LSS.

L1-pelvic angle: a convenient measurement to attain optimal deformity correction.

(1) Evaluate the associations between L1-pelvic angle (L1PA) and both sagittal vertical axis (SVA) and T1-pelvic angle (T1PA), and (2) assess the clinical impact of L1PA. A single-institution retrospective cohort study was undertaken for patients undergoing adult spinal deformity (ASD) surgery from 2013 to 2017. Ideal L1PA was defined as (0.5xPelvic Incidence)-21. Pearson correlation was performed to compare L1PA, SVA, and T1PA. Univariate/multivariate regression was performed to assess the effect of L1PA on mechanical complications, controlling for age, BMI, and postoperative pelvic incidence-lumbar lordosis mismatch (PI/LL). Due to the overlapping nature of patients with pseudarthrosis and rod fracture, these patients were analyzed together. A total of 145 patients were included. Mean preoperative L1PA, SVA, and T1PA were 15.5 ± 8.9°, 90.7 ± 66.8mm, and 27.1 ± 13.0°, respectively. Mean postoperative L1PA, SVA, and T1PA were 15.0 ± 8.9°, 66.7 ± 52.8mm, and 22.3 ± 11.1°, respectively. Thirty-six (24.8%) patients achieved ideal L1PA. Though the correlation was modest, preoperative L1PA was linearly correlated with preoperative SVA (r2 = 0.16, r = 0.40, 95%CI = 0.22-0.60, p < 0.001) and T1PA (r2 = 0.41, r = 0.62, 95%CI = 0.46-0.76, p < 0.001). Postoperative L1PA was linearly correlated with postoperative SVA (r2 = 0.12, r = 0.37, 95%CI = 0.18-0.56, p < 0.001) and T1PA (r2 = 0.40, r = 0.62, 95%CI = 0.45-0.74, p < 0.001). Achieving ideal L1PA ± 5° was associated with a decreased risk of rod fracture/pseudarthrosis on univariate and multivariate regression (OR = 0.33, 95%CI = 0.12-0.86, p = 0.024). No association between achieving ideal L1PA and patient-reported outcomes was observed. L1PA was modestly correlated with SVA and T1PA, and achieving ideal L1PA was associated with lower rates of rod fracture/pseudarthrosis. Future studies are warranted to better define the clinical implications of achieving a normal L1PA. III.

Surgical technique of combined minimally invasive anterior column realignment at L1-L2 with open extension of prior fusion.

Surgical correction of fixed kyphotic deformity or severe sagittal imbalance traditionally involves three column osteotomies, which are associated with high morbidity rates. Anterior column realignment (ACR) has emerged as a minimally invasive alternative for restoring segmental lordosis. This technique involves a lateral approach and release of the anterior longitudinal ligament (ALL), followed by placement of a hyperlordotic interbody cage. In this study, we present a successful case of minimally invasive ACR for the treatment of flatback deformity and adjacent segment disease in a patient with prior L2-S1 fusion. Imaging revealed a flatback deformity, sagittal vertical axis elevation, and spinopelvic disharmony. The patient underwent a multistage procedure involving a lateral retropleural approach for ACR and interbody fusion, followed by open posterior instrumented fusion and vertebroplasties. Postoperatively, the patient experienced significant pain relief and improvement in lumbar lordosis, pelvic tilt, and pelvic incidence-lumbar lordosis mismatch. ACR combined with posterior release allows for manipulation of all three spinal columns, leading to spine reconstruction and improved spinopelvic harmony. We discuss the advantages of ACR, including its minimally invasive nature and potential benefits for patients with sagittal deformities. The presented surgical technique demonstrates the feasibility and efficacy of minimally invasive ACR in addressing flatback deformity and adjacent segment disease.

Economic burden of nonoperative treatment of adult spinal deformity.

The purpose of this study was to investigate the cost utility of nonoperative treatment for adult spinal deformity (ASD). Nonoperatively and operatively treated patients who met database criteria for ASD and in whom complete radiographic and health-related quality of life data at baseline and at 2 years were available were included. A cost analysis was completed on the PearlDiver database assessing the average cost of nonoperative treatment prior to surgical intervention based on previously published treatments (NSAIDs, narcotics, muscle relaxants, epidural steroid injections, physical therapy, and chiropractor). Utility data were calculated using the Oswestry Disability Index (ODI) converted to SF-6D with published conversion methods. Quality-adjusted life years (QALYs) used a 3% discount rate to account for residual decline in life expectancy (78.7 years). Minor and major comorbidities and complications were assessed according to the CMS.gov manual's definitions. Successful nonoperative treatment was defined as a gain in the minimum clinically importance difference (MCID) in both ODI and Scoliosis Research Society (SRS)-pain scores, and failure was defined as a loss in MCID or conversion to operative treatment. Patients with baseline ODI ≤ 20 and continued ODI of ≤ 20 at 2 years were considered nonoperative successful maintenance. The average utilization of nonoperative treatment and cost were applied to the ASD cohort. A total of 824 patients were included (mean age 58.24 years, 81% female, mean body mass index 27.2 kg/m2). Overall, 75.5% of patients were in the operative and 24.5% were in the nonoperative cohort. At baseline patients in the operative cohort were significantly older, had a greater body mass index, increased pelvic tilt, and increased pelvic incidence-lumbar lordosis mismatch (all p < 0.05). With respect to deformity, patients in the operative group had higher rates of severe (i.e., ++) sagittal deformity according to SRS-Schwab modifiers for pelvic tilt, sagittal vertical axis, and pelvic incidence-lumbar lordosis mismatch (p < 0.05). At 2 years, patients in the operative cohort showed significantly increased rates of a gain in MCID for physical component summary of SF-36, ODI, and SRS-activity, SRS-pain, SRS-appearance, and SRS-mental scores. Cost analysis showed the average cost of nonoperative treatment 2 years prior to surgical intervention to be $2041. Overall, at 2 years patients in the nonoperative cohort had again in ODI of 0.36, did not show a gain in QALYs, and nonoperative treatment was determined to be cost-ineffective. However, a subset of patients in this cohort underwent successful maintenance treatment and had a decrease in ODI of 1.1 and a gain in utility of 0.006 at 2 years. If utility gained for this cohort was sustained to full life expectancy, patients' cost per QALY was $18,934 compared to a cost per QALY gained of $70,690.79 for posterior-only and $48,273.49 for combined approach in patients in the operative cohort. Patients with ASD undergoing operative treatment at baseline had greater sagittal deformity and greater improvement in health-related quality of life postoperatively compared to patients treated nonoperatively. Additionally, patients in the nonoperative cohort overall had an increase in ODI and did not show improvement in utility gained. Patients in the nonoperative cohort who had low disability and sagittal deformity underwent successful maintenance and cost-effective treatment.

Assessing Alignment Using GAP Score and Complications for Pedicle Subtraction Osteotomy Revision Surgeries for Sagittal Deformity in Previously Fused Spines Using a Satellite Rod Technique

Pedicle subtraction osteotomy (PSO) is a surgical technique to restore lumbar lordosis in patients with rigid sagittal deformity. Herein, we report on outcomes of a surgical technique utilizing a 4-rod PSO with satellite rods. A retrospective study was performed for a cohort of patients who underwent 4-rod PSO revision surgery for sagittal deformity. Procedures were performed by one surgeon at 2 different academic centers between 2004-2018. Alignment outcomes and complications specifically for revision surgeries in previously fused spines were assessed. 40 patients underwent PSO with the satellite rod technique (n= 29 at L3, 72.5%; n= 7 at L4, 17.5%). Mean PSO angle was 28.7 ± 7.6°. Two patients (5%) had rod fracture necessitating revision surgery at 32 and 34months. Three patients (7.5%) developed proximal junctional kyphosis (PJK), but none required revision. No patients developed pseudoarthrosis. Mean preoperative sagittal vertical axis (SVA) was 13.5 ± 7.3cm, which decreased to 4.8 ± 7.3cm (P= 0.002) postoperatively. Mean preoperative pelvic incidence-lumbar lordosis (PI-LL) mismatch improved from 35.9 ± 16.6° preoperatively to 11.8 ± 14.6° postoperatively (P < 0.001). Mean preoperative pelvic tilt (PT) improved from 34.7 ± 9.8° preoperatively to 30.1 ± 9.0° (P= 0.026) postoperatively. Mean global alignment and proportion (GAP) score improved from 10 ± 2 preoperatively to 8 ± 2 postoperatively (P < 0.001), which was still considered severely disproportioned. Rod failure rate after PSO with the 4-rod satellite configuration was low. SVA, PI-LL mismatch, and PT significantly improved for these previously-fused patients. Mean GAP score also improved, but was still considered severely disproportioned, likely due to the inability of PSO to correct low LL or PT in previously-fused spines.

Findings from a pilot randomized trial of spinal decompression alone or spinal decompression plus instrumented fusion.

Symptomatic spinal stenosis is a very common problem, and decompression surgery has been shown to be superior to nonoperative treatment in selected patient groups. However, performing an instrumented fusion in addition to decompression may avoid revision and improve outcomes. The aim of the SpInOuT feasibility study was to establish whether a definitive randomized controlled trial (RCT) that accounted for the spectrum of pathology contributing to spinal stenosis, including pelvic incidence-lumbar lordosis (PI-LL) mismatch and mobile spondylolisthesis, could be conducted. As part of the SpInOuT-F study, a pilot randomized trial was carried out across five NHS hospitals. Patients were randomized to either spinal decompression alone or spinal decompression plus instrumented fusion. Patient-reported outcome measures were collected at baseline and three months. The intended sample size was 60 patients. Of the 90 patients screened, 77 passed the initial screening criteria. A total of 27 patients had a PI-LL mismatch and 23 had a dynamic spondylolisthesis. Following secondary inclusion and exclusion criteria, 31 patients were eligible for the study. Six patients were randomized and one underwent surgery during the study period. Given the low number of patients recruited and randomized, it was not possible to assess completion rates, quality of life, imaging, or health economic outcomes as intended. This study provides a unique insight into the prevalence of dynamic spondylolisthesis and PI-LL mismatch in patients with symptomatic spinal stenosis, and demonstrates that there is a need for a definitive RCT which stratifies for these groups in order to inform surgical decision-making. Nonetheless a definitive study would need further refinement in design and implementation in order to be feasible.